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Jan 26

“Full Frame Equivalence” and Why It Doesn’t Matter

With smaller than 35mm sized sensors, you will often hear talk of a camera’s or lens’ “full frame equivalent” focal length or aperture. This can often be a source of great confusion among new shooters, and it can also be a point of disturbingly odd derision for other people, especially with regards to ‘aperture equivalence’. I’m going to try and give a clear view of what is truly meant when someone is talking about full frame equivalence, as well as dispel several myths about it, and ultimately tell you why, if you shoot with a smaller format, it mostly doesn’t matter.

Author’s Notes:  This article has been up for a while now, and from several comments I’m seeing with some regularity, I feel the need to make a few points.

  • This is not intended to show or imply superiority of any format over another.  At all.  I am not debating or arguing in any way that full frame cameras don’t have a better image quality baseline that crop cameras…they do as a general rule (same generation, etc). 
  • I fully believe that using ‘equivalence’ calculations makes perfect sense if you ‘think’ in 35mm terms, and thus it is useful in your mind to do the math to compare focal lengths, or even for depth of field calculations.  This is not an argument about using ‘equivalence’ as a point of reference.
  • This is about the use of full frame equivalence for people who have no reason to reference a format they don’t use, and against the far too often seen use of ‘aperture equivalence’ and how it relates to minimum depth of field as an absolute in determining the quality of a lens.
  • I have made some minor edits to the text in order to clarify some of the above.

What does “Full Frame Equivalent” mean?

First off, what does it mean when someone talks about a sensor or lens in terms of 35mm or ‘full frame’ equivalence? Well, quite simply, it is a way to compare angle of view, and more recently, the look you’ll get with respect to depth of field, between a full frame sensor and a ‘crop’ sensor. A few important terms to know:

  • Full Frame: A full frame camera has a sensor that is the same physical size as that of a frame of 35mm film. That is, 36mm wide x 24mm high.
  • Crop Sensor: A crop sensor camera, like on many DSLRs (which use the APS-C size) or the Four Thirds sensor (used in Four Thirds DSLRs and Micro 4/3 mirrorless cameras), is simply a sensor that is smaller in physical size than a full frame sensor.
  • APS-C: APS-C stands for “Advanced Photo System – Classic” (a reference to APS film), and means a sensor (or camera with that sensor) with a physical size between 22.2mm x 14.8mm and 23.6mm x 15.7mm.
  • Four-Thirds or 4/3: The sensor size used in Olympus and Panasonic DSLRs and mirrorless cameras (those of the 4/3 or Micro 4/3 system). The standard sensor size is in a 4:3 aspect ratio and is 17.3mm x 13mm
  • Field of View or Angle of View: The angle of view that the sensor will record for a specific camera and lens combination. For instance, a 24mm lens on Full Frame has a diagonal angle of view of 84°. This is the angle between the upper left of what’s captured by the lens and sensor and the bottom right (or vice versa).

See the diagram below. You’ll see arcs showing the diagonal, horizontal and vertical angles of view. In this diagram, the green rectangle represents the image captured by a full frame camera. If the same lens is used, the red rectangle represents the image captured by a crop sensor camera. It simply takes the center area of the image circle projected by the lens, resulting in a narrower angle of view.

A diagram showing angle of view and the effect a crop sensor has on a lens' angle of view

A diagram showing angle of view and the effect a crop sensor has on a lens’ angle of view

Crop Factor

One term that has been around since DSLRs made their entrance is ‘crop factor,’ which details the difference in focal length required for the same field of view between a smaller sensor camera and a full frame camera. This term was coined to help visualize that when you use lenses designed for full frame cameras on a crop sensor camera, the field of view is narrower…like cropping the photo in camera.

The first DSLRs used APS-C sized sensors because making viable full frame digital sensors at the time was cost prohibitive and very difficult. As the industry progressed, the APS-C sized sensors became somewhat of a sweet spot for high image quality with lower production cost.

The Crop Factor for an APS-C sensor is either 1.6x (Canon) or 1.5x (most others). What this means is that if you use a 50mm lens on an APS-C camera, it will have the same Field of View as a 75mm lens (50 x 1.5) on a full frame camera. The crop factor on 4/3 sensors is 2x, so a 25mm lens on a 4/3 or Micro 4/3 camera will have the same field of view as a 50mm lens will on a full frame sensor.

You will often hear people say “well, you have a crop sensor camera, so your 50mm lens becomes a 75mm lens on that camera.” This is WRONG. Focal length is a property of the LENS and the LENS ONLY, and it does not change in any way regardless of what camera you mount it on. What is true is that on an APS-C DSLR or CSC, a 50mm lens will have the same FIELD OF VIEW as a 75mm lens on a full frame camera. I’ll get more into this in a bit.

Digital Sensor Sizes and their "Crop Factors" - image by MarcusGR, Wikimedia Commons

Digital Sensor Sizes and their “Crop Factors” – image by MarcusGR, Wikimedia Commons

The key point to remember about crop factor is that it is ONLY a reference point. That is, if you are used to shooting 35mm film or a full frame DSLR, using the crop factor will help you select a lens focal length that will give you the same look that you expect from your experience with a full frame lens. If you know what a 50mm lens looks like through your camera, you now know you need about a 33mm lens on APS-C or a 25mm lens on 4/3 to get the same field of view. That’s IT. It serves no other purpose. More on that later.

Aperture ‘equivalence’

This is a new one. In the past few years, people have also been using the crop factor to relate so called ‘aperture equivalence.’ That is, they’ll multiply the F-stop of a lens by the crop factor to get the ‘equivalent aperture’ of a lens. This has some basis in reality, but it is a pretty major fallacy, in my opinion, and it really skews people’s perceptions. I’ve gotten angry and rude comments on this blog about how I’m delusional about Micro 4/3 because of aperture equivalence. Interestingly enough, this term really only started to be thrown around when Micro 4/3 started getting popular…it was almost never brought up with regards to APS-C DSLRs. There’s a little bit of fanboyism going on quite often with this. Anyway, let’s delve a little deeper:

A few things regarding aperture:

  • The maximum aperture of a lens is the size of the light opening of a lens when the blades of the aperture diaphram (the blades that open and close to let more or less light in) are wide open. More specifically, it’s the effective size of the opening that determines the cone angle of the light rays entering the lens. Aperture size is generally given as a ratio of the effective aperture size to a lens focal length. This is called the f-stop. If a 50mm lens has a maximum aperture of 25mm, it would be an f/2 lens. (Focal length/aperture = 50/25 = 2). The reason there is a division sign is because f/2 means the aperture size is the Focal Length / 2. (in this case, 25mm.)
  • The f-stop is one of the key components in exposure. The intensity of light hitting the film or sensor will be the same for the same f-stop, regardless of the focal length or actual physical aperture size. If you have a 200mm lens at f/2.8 and an 18mm lens at f/2.8, they both will have the exact same intensity of light hitting the sensor…the same number of photons per unit area. This, combined with ISO and shutter speed, helps determine how bright or dark your picture is. A larger number in f-stop means a smaller aperture (remember, it’s division: f/8 means the aperture is 1/8 the size of the focal length), which means less light hits the sensor.
  • A ‘full stop’ means the exposure is doubled or halved. With aperture and f-stops, a difference of the square root of 2 is one full stop. (1.4 is a good approximation to use). So, f/1.4 to f/2 is one full stop, as is f/5.6 to f/8 (5.6 x 1.4 = 7.9, or approx. 8).
  • Depth of Field: Depth of Field (DOF) is the depth of an image that appears to be in focus. Depth of field depends on three things: Focal Length, F-stop and Focus Distance (distance to your subject). These are all directly related. In fact, it is such that if you FRAME your subject the same way, all lenses will have the same depth of field for the same f-stop on the same format. To visualize this, consider a portrait where your subject is framed with the tops of the shoulders at the bottom of the frame, and the top of the head right at the top. If you frame your subject with a 50mm lens at f/2, then move BACK twice the distance you originally stood and use a 100mm lens at f/2, the depth of field, or amount that subject is in focus, will be the same.
  • Background Blur: The amount that the area behind your subject is blurred. Using really wide-aperture
    A candid with noticeable background blur due to a large aperture lens - in this case the Olympus 75mm f/1.8 on the OM-D E-M5.

    A candid with noticeable background blur due to a large aperture lens – in this case the Olympus 75mm f/1.8 on the OM-D E-M5.

    lenses, like f/1.4, can yield very blurry backgrounds, while your subject remains sharp. While background blur is related to depth of field, they are NOT the same thing. Background blur is dependent on the same three things as depth of field, but in a different way. While depth of field relations depend on focus distance, f-stop and focal length, background blur can be simplified from that: It is wholly dependent of focus distance and physical aperture size. The mathematicians here are having a field day saying that since physical aperture size can be determined via focal length and f-stop that they are they same…but the relationship is different. Let’s look at that example from the previous bullet point. While a 50mm shot at f/2 and a 100mm shot at f/2 that’s taken from double the distance as the 50mm shot will have the same depth of field, the 100mm shot will have a BLURRIER background. Why? While the f-stop is the same between a 50mm lens at f/2 and a 100mm lens at f/2, the 100mm lens has a physically larger aperture (50mm vs 25mm). We can get into the reasons why this works (mainly, you are enlarging the area behind the focus point more with the longer focal length), but the big rule of thumb is, for the same focus distance, lenses with the same physical aperture size will yield similar amounts of background blur.

So, after all that drivel, what’s this aperture equivalence speak? Well, it refers entirely to the comparison of depth of field for a given sensor/lens combination. That is…you can multiply the f-stop by the crop factor to determine the aperture on a full frame camera that will give you the same depth of field.

So, if I shoot a portrait with a Micro 4/3 camera and a 25mm f/1.4 lens, and I shoot it at f/1.4. The field of view, depth of field and amount of background blur will be the same as if I’d shot the image at the same spot with a full frame camera, and a 50mm lens at f/2.8. Since Micro 4/3 has a crop factor of 2: 25mm x 2 = 50mm lens for the same field of view, and f/(1.4 x 2)= f/2.8 for the same depth of field. Similarly, 25mm/1.4 = 17.9mm aperture size and 50mm/2.8 = 17.9mm aperture size (so same amount of background blur at the same focus distance).

This means that, all things being equal, a smaller format will generally have DEEPER depth of field and less background blur than a larger format. This makes sense because smaller format cameras use shorter focal lengths for the same field of view, and therefore similar f-stops mean a smaller physical aperture size: less blur.

Total Light

One final nitpick that people like to point out on aperture equivalence is that it also shows you the settings that not only yield a similar image, but also allow for the same total amount of light used to make an image. For instance, a full frame sensor is four times larger in area than a Micro 4/3 sensor. Therefore, if the f-stops are the same, and thus the intensity of the light is the same (and the exposure is the same), then the full frame camera will be using four times the total amount of light to make the image because it’s got four times the total area. For the smaller sensor to have the same total amount of light, they need two stops faster aperture or two stops lower ISO with a longer shutter speed. This is why, often, it’s said that full frame sensors will have two stops better ISO performance over a Micro 4/3 sensor.

Noise comparison - OM-D E-M5, Canon 5D and 5D Mark II, Courtesy, DxO, Click to Visit DxO Labs Comparison Tool

Noise comparison – OM-D E-M5, Canon 5D and 5D Mark II, Courtesy, DxO, Click to Visit DxO Labs Comparison Tool

However, this doesn’t work completely linearly in the real world, as smaller sensors are more light efficient than larger ones, and it is also dependent on sensor technology being identical. If you look at the DxO Mark sensor comparison, you will see that if you compare the Olympus OM-D E-M5 with the Nikon D600 and the Canon 5D Mark III (both of which are full frame sensors), they measure roughly 1 2/3 stops better in ISO performance. Not two like you’d expect.  You may be thinking ‘that’s close enough, but it speaks to the further point:

Compare different sensor generations and everything breaks down, though advocates of this equivalence never use the equivalence when comparing full frame sensors of different generations. The OM-D E-M5 is only about a half a stop behind the Canon 5D and just over one stop behind the 5D Mark II…a camera that was current only 9 months ago. (See chart above).

My whole point here is that the total light argument implies a direct 2x or 4x improvement in image quality with ISO. However, this is really only true for approximating how one sensor design may scale with size, but is terrible as a blanket equivalence based on sensor size alone due to the changing of technologies over time and differnent sensor construction even among cameras of the same generation.

Now, let me tell you why none of this matters: Next Page

About the author

Jordan Steele

Founder and Editor-in-Chief of Admiring Light; Photographer; Electrical Engineer and Dad

178 comments

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  1. Andreas Fougner

    Great article! It is getting tiresome to read about the 35mm equivalence on the internet. It seams like most people havent even tried full frame or m43. The common opinion seams to be that a bigger sensor is always better. Neglecting all the benefits of, for example, m43. Although I too fall for the shallow dof virus sometimes, I always tend to come back to affordable, light and quick. Another benefit of m43 is telephoto range in a small package. The system will be complete when we get fast long teles like 300mm f2.8 or f4.

  2. Tadej Trstenjak

    Excellent!
    Article which combines all in one. Thanks for this!
    I’m using m43 for more than 1:1 macro photography (really narrow DOF) and this system helps me a lot. I don’t need high ISO because I always shoot with base 100 ISO and flash.

    1. Maneesh

      Except that 1:1 on a smaller sensor implies smaller part of the image than it does on larger sensor. For example, a 36mm wide sensor will record 36mm image across at 1:1, but Micro-four thirds will record only half of it.

      1. jefkom

        That means 2x the magnification on the 4/3 sensor.

  3. Mandeno Moments

    I am basically in agreement with what you say here. I use four different sensor sizes and find that using the (arbitrary) 35mm-equivalent field-of-view number gives a commonality across the cameras that is essential for previsualisation. As you more or less say, this is just confusing and unnecessary for a beginner using one sensor size.

    Hypothetically you could use the ratio of focal length to sensor diagonal to give commonality across different sensor sizes (in regard to field of view): that would just cause more confusion for those used to 35mm-e, but otherwise it would be functionally equivalent. This demonstrates the arbitrary nature of any system used to compare fields of view across different sensor sizes.

    Has anyone looked into the effect, if any, of different focal lengths with equivalent FOV when recording the motion blur of off-axis subjects approaching the camera? E.g., does a 6mm lens with a 1/1.7″ sensor record more, less, or the same amount of motion blur as a 28mm lens on 24x36mm sensor and a 14mm lens on a 4/3 sensor?

  4. Greg Kelson

    Really valuable article Jordan. Excellent explanation of some poorly understood concepts.

    I guess this is why I keep coming back to your site.

    Thanks

  5. Oskar

    well said. the inconvenience of FF shallow dof is pretty easily overcome though: take a few steps back and crop in camera or in post. if the space doesn’t allow it – well you would have had that problem with a crop sensor to. change lens!

  6. Thomas

    Thanks! Very well written and very true! Also a very valuable article for people with GAS ;)

  7. Mike

    Great article. I really enjoyed he plain English description of the concepts behind the jargon, and the practical examples of their application.

  8. Maksim Images

    Being 4/3 shooter myself, I find I need deeper DOF most of the time. If I really really want super shallow DOF I use 30mm 1.4 Sigma and some pp in software, but that’s rarely so.
    My opinion is that shallow DOF is used mostly when you don’t have or don’t know how to compose the background into the picture so this is an easy way of covering it up.

    1. Eric Bogan

      And my opinion is that your opinion of shallow DOF shows you do not understand photography beyond what you shot and like and are rude. Having everything in focus in every picture regardless of subject to me is poor photography.

  9. Maksim Images

    I agree with all points. I have a question though. How would you compare Canon FF (mainly interested in 5D Classic) to OMD with regards to DR ISO and tonal range ?

    Im on a verge to diversify from E-5 and replace it with 5D and some primes (50/135/85 which will take long time to collect). I would leave my 4/3 lenses to use on EPL-5.
    Btw. for all naysayers about sensors and DOF I would share my flickr page to see what’s possible to be done with older generation of 2xCrop sensor:
    http://www.flickr.com/photos/maksimimages/

    1. Jordan Steele

      I have not used the 5D, but have extensive experience (and still own) a 1Ds Mark II. The Om-D is very slightly behind in noise to that (but not much…maybe half a stop in practical use), but I think it’s got better DR and I even like the skin tones better in formal portraiture.

      1. maksim images

        1Ds Mk2 came out at the same time as 5D (2005). It has a bit larger number of pixels which probably means its a bit behind 5D in noise department.

        If you believe 1D mk2 is ahead of OM-D noise wise then it’s safe to assume the 5D is as well ?

  10. Wassup

    You hit on my pet-peeve. 50mm is not “normal” on 35mm, it is “standard”. The misnomer of “normal” for 50mm lenses (and worse, for 55 and 58mm lense) came about because of some arbitrary choices 50+ years ago by manufacturers. 50mm lenses are easier to design and cheaper to build at high quality than any other focal length, especially back then, so they became the standard lens for 35mm cameras. But 50mm is definitively NOT normal. Normal is the diagonal of the film or sensor, so 43mm on 35mm, or something VERY close to that, like 40-45mm. Similarly, for APS-C normal is 28-30mm, and for 4/3rds normal is 20-23mm.

    1. Jordan Steele

      You can’t fight the English language! :) While you are correct that the formal definition is equivalent to the diagonal of the capture medium, the term has come, over the past 80 years, come to mean anything around that length, and, specifically, to 50mm in the 135 format, despite being longer than usual. Even the Wikipedia article, while relaying the mathematical definition, acknowledges the use of a 50mm lens on FF as normal: http://en.wikipedia.org/wiki/Normal_lens

    2. Paul C

      Actually, you’re both somewhat wrong about the “normal” lens. A lens of focal local length equal to the diagonal of the medium yields a perspective and angle of view close to that seen by the human eye. The “normal” designation refers to the perspective offered by the lens; normal as in “seeing normally”. For 35mm, it works out to about 46mm, which is one of the reasons that 45mm “normal” lenses were common on 35mm cameras. 50mm lens became popular for two reasons: one, a slight telephoto image was more attractive for compositional control, and the big reason, the bigger glass allowed more light and lower f-stop capability without unbearable distortion. It was also an easier size to make a multi-element lens for distortion control and keep the sweet spot of the lens within the low distortion circle of confusion.

  11. J Shin

    > Since Micro 4/3 has a crop factor of 2: 25mm x 2 = 50mm lens for the same field of view, and f/(1.4 x 2)= f/2.8 for the same depth of field. Similarly, 25mm/1.4 = 17.9mm aperture size and 50mm/2.8 = 17.9mm aperture size (so same amount of background blur at the same focus distance).

    Since the two scenarios would have the same field of view at the same focus distance, doesn’t this actually prove the “equivalence” between them?

    Where the difference really happens is shutter speed when hand-held. The 25/1.4 lens calls for the use of a shutter speed 4 times what would be used for 50/2.8. However, to prevent motion blur, the smaller sensor only needs to use shutter speed twice as fast. So, in a scene that the full-frame version would need f/2.8 1/30″, for example, can be shot with mFT at f/1.4 1/125″, producing the same field of view, depth of field, and background blur, but one-stop gain in motion blur. Or, we could do f/2.8 1/30″ ISO 400 in full-frame, vs. f/1.4 1/60″ ISO 200 in mFT, with the same motion blur and the same SNR. So, if mFT sensors can stay one stop behind full frame sensors in SNR (actually, your graph shows that it is a little less than 1.5 stop behind, not 1 stop), all things are basically equal. Unfortunately, E-M5 is actually two stops behind D800, so mFT remains one stop inferior in image quality to FF.

    1. J Shin

      Sorry. Didn’t see page 2. Oops.

      1. Robert Mark

        You’ve completely discounted the 5 axis IBIS that is a huge advantage of the OM-D bodies. I’m getting shots at ISO 1600 on my OM-D that used to require 6400 on my 5D3 (combination of faster lenses and slower shutter speed).

  12. Gavin Wilson

    Great article but it went right over my head when got to talking about the science of light and apertures….please keep it in simple terms.

    1. maksim images

      Some of us like technicalities, so please keep ‘em coming.

  13. Ricci

    Great article! Thank you.
    This article should be on the first 2 pages of every photo book published today.

  14. cosinaphile

    JMAN ….the best article on the topic anywhere on the web

  15. Woof

    THANK you! Much appreciated. This is one of those things you wish someone else would write so you can drop a URL in a discussion and be done with it. Well done, and very much appreciated.

  16. Sleeper

    I was going to come in here and call you delusional. Full frame IS better. FULL STOP. But…

    “The Fallacy of Aperture Equivalence” is so very true. Us who use FF stop down a lot. You are so very right in those points.

    However, there’s one point you can’t argue against. Full frame in the f/5.6 to f/11 (not diffraction limited) + tripod/enough light shot at its full prime in base ISO printed in A3 or A2 CANNOT be matched by anything smaller in terms of the quality. That’s why I’m sticking to FF. Yes we all are very well aware of the trade off.

    Nice article.

    1. kwilkins

      I beg to differ

      Take a 12MP 35mm sensor, shot of a model with everything but the background in focus. So lets say f/11
      Take a four thirds sensor, same shot, same MP count, at f/5.6 or f/8

      Crop both to be a 10MP image to the ratio for A2 and print.

      Same MP count, both base ISO so no noise, i would bet on you not noticing the difference.
      For fun, repeat the shot with a medium format, with higher MP and print at A2 and compare them at viewing distance. Again, viewing distance would mean for A2 no more than 200ppi image sent to a high quality printer. (for A3 you can use 200-250 without a problem and A4 you want 300-350)
      Again, I doubt the difference would be seen.

      Where FF does win out is the high pixel counts, yet higher pixel counts means the circle of diffusion (which is what the diffraction limit is based on) to get the best results from the sensor decrease, meaning the diffraction limit is no longer f/16 and could be f/8 in some cases (Nikon D800 springs to mind)

      The main point, you have a camera, you have lenses, you have your desire to take pictures. A pro shoots with his kit and worries about clients, amateur worries about his lenses and the beginner worries about his camera.

      1. arad85

        > yet higher pixel counts means the circle of diffusion (which is what the diffraction limit is based on) to get the best results from the sensor decrease

        No, no, no…. The CoC (actually, the circle of confusion diameter limit) has absolutely nothing to do with pixel size. It has everything to do with how much you are magnifying the image to get to a print, so is dependent solely on sensor size. It defines the amount of blur that is on the sensor that can be seen in a print – and typically CoC diameter limit is many pixels across.

        If Joredan is OK, here’s a link describing CoC in more detail: http://photo.andysheen.co.uk/technical/depth-of-field-and-what-affects-it-explained/

        1. Dr A Berke

          Hmmm – the Zeiss formula would differ (i.e. CoC = linear relationship between diagonal of media – sensor or film) Plus, a pixel is not a standard size – nor does either relate in film terms.

          On larger sensors – i.e. a mythical one pixel/one sensor camera – the CoC could be much less than the pixel …

          For all practical purposes, at point of CAPTURE, CoC is actually sensor/media dependent.

  17. tomas

    does have adapter(without glass) any affect what is mention about lens aperture vs. light gathering ? eg. OM/m43 adapter

  18. OptionalD

    I agree with you that equivalency is largely irrelevant. It was more important when people were moving into digital from film. Most photographers coming up now have never even shot on real film. However, I do have to take issue with the choice of 35mm as being arbitrary. If 90% of photographers coming from film shot 35mm then that makes it an obvious and most useful frame of reference. Yes medium or large format or even 110 could’ve been used but that wouldn’t really make sense for most photographers, would it? Standards will be based on the most widely used and understood measures. Or at least they should be.

  19. Jeremy

    I’d notice the full frame lens center sharpness always better than the lens of the smaller format sensor system. This is the another advantage of the full frame system but I don’t know how important it is related to the final image clarity if comparing between full frame and smaller sensor system.

    1. arad85

      You’re wrong about the FF being sharper in the centre than smaller formats. The micro 4/3rds lenses lead the pack on consumer lens sharpness. It’s just most people are used to seeing resolution quoted as line pairs/image height (which means how many lines you can project onto the sensor) whereas sharpness is really defined as line pairs/mm – in which case the micro 4/3rds win out….

      1. Jeremy

        I just read thru the “Perceptual Megapixels” and compare the lenses test result from the dxomark. It’s seem FF system lens sharper than 4/3 lens.

        1. arad85

          Well.. the numbers are bigger for FF over m4/3 but no, that doesn’t mean they are sharper. It doesn’t describe the resolving power of the lens – nor does it claim to. It only allows comparisons of lenses a particular camera – not even across different cameras with the same size sensor. It does mean that sensors with a high Mpixel count are able to score very highly with even mediocre lenses though….

    2. Robert Mark

      You’re mistaking corner softness of the 35mm lenses compared to the corner sharpness of the Micro Four Thirds lenses.

  20. lisandra

    RIght on the head Jman. I have no problem achieving thin DOF in m4/3s when I want it. Otherwise I was brought up with the thought that a thin DOF is more a problem than something you would want. Now the new ridiculous argument is that 4/3s lenses are more distorted because they have to be wider. Itll never end
    Jeremy the center is sharpness but the corners are poorer. Making a corner to corner sharp full frame lens is quite a task

  21. Mei

    Nice article. Once you shoot with equivalent depth-of-field and same shutter speed, you force larger sensor into higher ISO, and all the dynamic range and noise advantage of larger sensor disappears. There’s little advantage in full frame.

    I think there’s generally a lack of depth-of-field. Many photos out there simple needs to depth of field. In many videos shot with 5D, the subject drifts into and out of focus. Razor thin depth-of-field is just a fetish. Artistically, it’s pretty bland.

  22. Stupig

    The problem has never been with “equivalence” – it’s been about A) misleading marketing, B) denial of ignorance, and C) people who do not appreciate others’ choice.

    A) – saying m4/3 17/1.8 is a 34mm FOV equivalent lens with an aperture of F/1.8 is like Bill saying he didn’t have “sexual relationship” with Monica. Such a statement is technically valid but misleading nevertheless (Hey! They didn’t say it’s 34/1.8 equivalent).

    B) – someone reads of the 34mm FOV with F/1.8 aperture claim, and half wishfully and half unknowingly assembles these figures into “34/1.8 equivalent” in his head. And when the reality of equivalence struck, he goes into denial and gets defensive.

    C) – there are those who clearly understand what the equivalence works, and made the highly informed choice to forgo bokeh quantity for convenience and unobtrusiveness. However, not everybody appreciates such choice and keeps calling smaller formats “crap” simply because they give less bokeh for the same money per lens.

    Back to the linked article – Page 1 pretty much falls into B) category. The technical comparisons are not fairly made. For example, DxOMark’s ISO rating should be disregarded, and dynamic range should be compared instead of SNR 18%. Page 2 makes reference to A) with a voice pointed at C). However, more fundamentally, the author doesn’t understand equivalence at all.

    1. Bob

      There’s no such thing as “less bokeh”, or even “bokeh quantity.” Bokeh is NOT the same as DOF.

      DOF is the range of the image, in front of and behind the focus point, which appears to be in focus. (Technically, only the plane at the exact focus point is in focus, but because the human eye is forgiving, we see a wider range of the image as subjectively sharp enough to appear in focus.)

      Bokeh is the subjective character of the out of focus areas. To restate: DOF is the in-focus part of an image, bokeh deals with the out of focus areas.

      Bokeh can’t really be measured. It’s very subjective. Are the out of focus areas “creamy” or “harsh”? Do OOF highlights blend smoothly into the shadows, or are the edges harder, and more distracting? That’s bokeh, and you can’t have “more” or “deeper” bokeh. Bokeh is completely dependent on the lens and aperture used, and not remotely related to the format of the sensor. There are FF lenses with lousy bokeh, and m43 lenses with great bokeh. And vice-versa.

      At least learn the language of your hobby, and use it correctly. Write on the blackboard 100 times: Bokeh is not the same things as depth of field.

  23. Libby

    “Why don’t we make 645 medium format the ‘reference’. Then ‘full frame’ would have a crop factor too?”

    Oh could we start a movement and please do that? ;-)

    Brilliant article. When I started shooting back when I was 13 it was on 4×5 and 120, so 35mm film was a huge disappointment. when I started to use it. College budget was the reason – I could buy bulk rolls. Presently I use FF, APS-C, m4/3 and MF. Each has its own advantages and characteristics. For daily walk around general shooting, I choose m4/3. Fun shooting and good quality.

    1. Eric Bogan

      35 mm is the reference because we are talking about DSLR cameras and that is what film SLR cameras shot. Now we have DSLRs so we reference 35 mm which is where we came from and makes great sense. And crop factor to me only relates to DSLRs. And is only useful as a general FOV difference.

  24. McGillicuddy

    Brilliantly and very eloquently put… If people took more time in practicing core camera craft instead of becoming “gear entrenched” the photography world would be a far better place… Just my 2p’s worth

    Super article

  25. Mike

    Jordan, you’ve forgotten one extremely important aspect in the whole equivalency discussion. It is that (micro) four thirds lenses are tack sharp wide open at f/1.4 or f/1.8, while full frame lenses usually need to be stopped down to f/2.8 to become sharp. This brings the equivalence much closer…

    Also, if most pros consider f/2.8 zooms on full frame “good enough”, them tack sharp f/1.8 primes on micro four thirds are equally “good enough”. One gives you the zoom advantage in exchange for bulk, the other lets you carry way more lenses and a more discrete camera.

    I own both. I use the micro four thirds far more often because its more enjoyable to carry with you…

  26. Matt J

    Excellent article breaking it down! I went from Canon APS-C to an OM-D EM-5 and absolutely do not regret it. This article really enforces my opinion that I made a good choice!

  27. Sascha

    Two sides of an article:

    First, the article is right saying people shouldn’t worry about sensor size or equivalence unless they are actually using or going to use different formats, because there is no need for a reference point beyond your own world. I’m using different formats, but seldom at the same time, so there is no need to think about the equivalence of, let’s say, my 20mm f/1.7.

    Second, the article is wrong talkiing about the aperture, because it stops at the wrong point leaving a big part of equivalence untouched. With an 75mm f/1,8 on Micro-Four-Thirds you get the same relative amount of light as with an 150mm f/1,8 on Full Frame, thats correct. But you don’t get the same absolute amount of light. That is, of course, the answer of why full frame cameras have less noise, but it affects other points to. For example the wider range of usable apertures, or the higher level of details possible. Image a perfect lens and a sensor with infinite resolution: full frame will capture four times more details with the same aperture, just because the absolute amout of light is four times as high.
    And that’s also why your given examples are wrong, because you forgot the relative nature of ISO. There are no benefits of a larger depth of field with the same aperture, so there are no benefits of smaller sensor sizes within macro or studio photography.

    But it works also the other way around: as long as you want a fixed depth of field, you will get no advantage with larger sensors. You will neither have a better image quality with higher resolution or less noise, nor will it affect the photographic accesoires like strobes, tripods etc.

    Because of that i decided to use Micro-Four-Thirds as my main system. I’m composing the pictures in my head before taking them with my camera, so I know which field of view, depth of field and exposure i need, and most of the time MFT is working fine. Only when I’m reaching the borders I need to change equipment, for more depth of field or a higher resolution, meaning full frame or medium format. The rest is silence.

    1. swampwitch99

      I get the feeling you are the real artist here :)

    2. Bob

      Wrong. If you assume a sensor with infinite resolution, the “four times as much light” falling on a FF sensor won’t increase detail at all. At that point, detail will be dependent solely on lens resolution.

      The only advantage of the greater total light falling on a larger sensor is noise performance. (There are other advantages to a larger sensor, but not because gathers more total light.

      1. metapatterns

        I agree with Bob. In the thought experiment presented (perfect lens + sensor with infinite resolution) I can understand the argument that at the level of individual photons you would technically be collecting more information, but more information is not necessarily equal to more detail, which was stated as the expected outcome. Across some reasonable (and probably very tiny) threshold, the amount of light is sufficient to provide as much detail as is possible to record given the effects of air, heat, and other light-affecting phenomena.

        In any case it’s an academic experiment: we’re not anywhere near the limits where this thought experiment is useful when discussing actual optics and sensor technology.

  28. Bill Miller

    Good article and I agree with you all the way. I sometimes get comments on my website about the equivalence thing, but only if I mention a picture has been taken with a m43 camera. If I don’t say which camera, most people cannot tell at all – so I let the pictures do the talking now !

    1. Eric Bogan

      Right on! The equipment is rather meaningless. The end result is all that maters. The rest is drivel. Us what gets you the shot you want. This pixel peeping and poring over data and arguing quality, etc… ect… maybe fun(?) but is rather silly and meaning less.

  29. DrDave

    I prefer to say that the F stop is a ratio rather than “passing the same amount of light”. The problem as I see it is that people interpret this in different ways.

  30. flix

    Good article with a lot of truth in it, but I think your conclusion is wrong.
    – Why 35mm as a reference? Because 35mm was by far the most used format until the early/mid 2000’s and many people can imagine the effects of certain focal lengths in this format.
    – You arbitrarily pick cases where the equivalence does not matter/is in favor of MFT. One could easily pick other cases where it is actually important. MFT cannot compete with the low light performance of 35mm when there is no need of deep depth of field and/or the subject is moving, MFT cannot compete with the low ISO performance of 35mm (and 35mm cannot compete with the low ISO performance of medium format), etc.
    – The equivalence holds regarding FOV and depth of field. It more or less holds regarding ISO. That does not make it completely useless.

    The thing is that one should be aware of the limitations of a system when deciding which one to buy or which one to take with you on a trip. That is where the full-frame equivalence comes in handy.

    My conclusion is: full-frame equivalence matters – SOMETIMES ;)

    1. maksim images

      I actually think it can (compare with low light ability).

      Compare for example 5D and OM-D in low light scenario.

      I believe author did mention it all depends on sensor technologies and their generations. So old 4/3 Panasonic sensor from E-510 will not compare nicely with A99 FF of new generation same way as new 4/3 Sony sensor will be better then old Canon FF.

    2. Bob

      I’m willing to bet the vast majority of today’s DSLR shooters NEVER shot 35mm SLRs, but cut their teeth on APS-C cameras or even smaller sensor P&S cameras. To these photographers, 35mm equivalence has no meaning at all.

      APS-C would be a much more useful baseline for comparing formats for most people. But that wouldn’t let DSLR shooters criticize m43 as easily, because the differences in DOF, noise, and other areas of performance are much smaller.

  31. Sean

    Nice article. Sadly it will probably just add fuel to the flame wars. Prepare to have your article picked apart and criticized by those who enjoy spending so much time discussing such things that you wonder if they ever photograph anything beyond a test chart. I have used 35mm film, APS-C DSLR cameras, and m4/3. They all have their pros and cons, but when it comes down to the photography I do today m4/3 is just the best fit for my lifestyle. Personally I am satisfied with the amount of depth of field control I have as well.

    I really don’t get the total light thing. Why should I care? All that matters is that enough light is hitting my sensor to create a good exposure and a pleasing photograph. I am happy with the results I get using my OM-D… Even in very low light thanks to fast primes and the OM-D’s high ISO performance. I also use it on a tripod for landscapes and architecture. I see no point in discussing equivalency between different formats unless you are making a direct comparison. I really wish people would stop using 35mm equivalency on a m4/3 discussion board when they are simply trying to describe the focal length they used. Just say the actual focal length of the lens!

  32. acahaya

    Thanks for this article, imo you did very well when pointing out that equivalence is not about the question of which format is the better one but to show under which circumstances you will be able to shoot “(almost) the same image regarding FOV, DOF, Motion blur and noise”.
    Unfortunately equivalence is almost always misused as a rating system and very often confused with exposure.
    This is why people start telling us that mFT 75/1.8 is always just a 150/3.6 on FF and others will tell us that it is a 150/1.8 – both statements are wrong because they forget to mention the other parameters.

    Im actually waiting for someone to write down an extended equivalence theory that somehow adds weight into the equation ;-)

    Regards -Sabine

  33. Daniel

    FF anyway better than crop.

  34. FotografnuntaIasi

    This article is responding me to some tricky situation. thanks!

  35. Future MFT user

    Great article and beautiful daughter of yours, Jordan.

    IMHO (and many others, I can tell!), MFT represents the most balanced ratio for IQ/DOF/size/weight. Anything smaller and you begin compromising on IQ and DoF. Anything bigger and you begin compromising on size and weight. MFT sits down just in the middle, giving good enough IQ and DoF for the vast majority of usages, while having a nicely portable and lightweight system.

    Now, even if some day Canikon could make FF mirrorless cameras as small as today’s MFT cameras, then Olympus and Panasonic will be able to make even smaller MFT cameras, simply because the laws of physics. Therefore the perfect balance of IQ/DOF/size/weight will still be there.

    1. maksim images

      But lenses is what adds bulk to the system, even if the body is the size of an iPhone.

  36. stando

    Thanks, very good article. Clear, precise, clever, very detailed and well balanced. … I say as APSC owner, which is not attracted by 43.

  37. Florian

    Thank you for your useful, clear and well-written article! The statements about apertures, focal lengths and so on become even more confusing when people write about the new “speed booster” ….

    Florian.

  38. Paul Adams

    Excellent article. Thanks for taking the time to explain the concepts of F-stops and aperture equivalency for the photographic community. Even though I’ve been shooting for years, its always good to go back to the basics once in a while. Plus it gives me ammunition for those tiresome conversations about MFT versus “real cameras.” :-)

    Cheers,
    Paul, Vancouver.

  39. luca vascon

    Finally… finally someone that put in clear words the facts behind sensor sizes and focal lenghts meaning.
    Being an engeneer and a specialistic commercial photographer I always had the scientific approach to the matter. However it is a very hard battle against marketing claims and people ignorance. In the same way it is impossible to keep working without an heavy CakiKon camera with you. Unfortunately also Hasselblad is no more percieved as “a professional camera”from the medium customers. My own personal choice is for the Olympus m4/3 system, the professional one is D800E and 5Dmk2.
    Many of the “professional images” that are sold are.. done with an Olympus and chosen by customers themselves.

  40. June Hudson

    Thank you for posting this! Your explanation of the different kinds of sensors is clear and I feel more knowledgeable. I switched from a Canon Rebel XSi to a Canon 5d mark ii over a year ago and could see a difference, but couldn’t really explain the differences to other people. Thanks again!

  41. Victor Trasvina

    Outstanding writing ! Its a shame to see what marketing and misinformation has done to photographers in general, when the reality ITS ALL ABOUT THE QUALITY OF THE FINAL IMAGE REGARDLESS OF WHAT EQUIPMENT WAS USED ON THE PROCESS ” now days we seem more concern with bragging about the latest “specs” our gear has than understanding the capabilities MOST systems have to offer when used properly are simply mind-blowing . After many many years of walking around with full frame sensor DSLR’s and a bag full of heavy primes i recently bought a FujiFilm X Pro 1 (a decision purely based on ergonomics as the OM D ecosystem is just as great if not maybe even better) and i just couldn’t be happier with it, at least on my personal experience the trade off has not only has been minimal but well worth it since now i can walk around with a very competent set up ALL the time (i take it EVERYWHERE i go unlike my DSLR’s) so its very refreshing to see articles like yours helping people understand a little better not only some of the math behind it but to remind us that this is an industry always evolving and moving forward so might as well embrace it ! :)

  42. Peter Arbib

    Great Article with easy to understand explanations.
    I would like say that reversing the DOF difference in a Studio Session really shows that the smaller than FF sensors has an advantage in using brighter f/stops and still having better DOF. was a good idea to show WHY you should use a APS-C or m4/3 instead of a FF camera in a Studio, or Interior photo shoot. I don’t know many, if any people, that will pay for one eye being in focus in the business end of selling portraits.

  43. Cezar Popescu

    Depth of field depends on three things: Focal Length, F-stop and Focus Distance (distance to your subject).
    Im a bit confused: you forgot about disc of confusion :)

    1. Bob

      I think you mean “circle of confusion.” But that is dependent on the focal length and f-stop, so the author is correct.

  44. baphoto

    Great writeup. The best camera only makes it easier for the best photographer to do what he/she can do with any camera.

  45. Dexter Legaspi

    I am mostly in agreement with you, but you have to remember that 35mm is the “magic reference” that you speak of is the most common one, just like you said, in these times…and that would be the point of reference to most photographers today, so seeking an equivalence to the most common denominator is inevitable.

    so this second part of your article would rub the wrong way to a lot of folks because it sounded fanboyish…i personally don’t mind the bias and I think your candid/honest outlook on this touchy subject is refreshing.

    1. Milkiwei

      35mm is only the most common in consumer film photography, but not digital. It’s conventional, but not magical.

    2. Fri13

      What is most sold format in Canon cameras or Nikon cameras?

      35mm or APS-C? Or even smaller in pocket cameras?
      What is most common camera consumers have these days? A DSLR, pocket camera or Smart Phone?

      Exactly, 35mm is as rare as is medium format when compared to pocket cameras and especially smart phones.

      What should be the reference point? For consumers it should be a 1/1.8″ sensor and for professionals a APS-C.

  46. KFC

    I think full frame equivalence is incredibly useful. I use 35mm film, an APS-C camera, and 645 medium format. In the next couple of years I’ll probably have a full frame digital camera as well. Using the 35mm equivalence helps me ground all 3 of them and compare field of view in a sane way. It’s a lot less effort to multiply two numbers than it is to memorize focal length = number of degrees for 3 separate formats; then all you really need to know is one set of field of views, and a multiplier for each format. This article spent all of about 1 sentence on that subject.

    1. Bob

      Which is pretty much exactly what the author said equivalence was good for…..

  47. Bob Muenchen

    Thanks for the great article! I think you’ve got a typo on page 1: “If you have a 200mm lens at f/2.8 and an 18mm lens at f/2.8, they both will have the exact same intensity of light hitting the sensor…the same number of photos [photons?] per unit area.”

    1. Jordan Steele

      Thanks! Corrected.

  48. Eugene

    Wow, I really enjoyed this one Jordan. Amen!!! I have to say, made my day.
    Now I have to talk about this on my flickr post and share. I hope you don’t mind me sharing this post.
    Thank you very much!

  49. Mark Mason

    Excellent article, Jordan. Hit the nail on the head. I’m in the same stream as yourself I think: enjoying taking photographs again with a small, lightweight, high quality kit. And the work is good and printable much larger than anyone is interested in buying!

  50. Paul

    As we now live Ina multi format world (more every day) it is useful to have a baseline reference for perspective and DOF. As most people have experience from 35mm it is understandable to compare with this rather than other formats. I use 35mm FF, 1.5x crop, m43 and also 1/1.7″. Most of the shots I take are on the smaller sensor formats due to portability and convenience.

    “What IS true is that the 75mm f/1.8 is not capable of the same ultra shallow depth of field as, say, something like the Canon 135mm f/2L on full frame. However, this is essentially the ONLY way that it is inferior. It passes the same amount of light, and it exposes as an f/1.8 lens because it IS an f/1.8 lens”

    Need to be able to differentiate equivalence of light intensity and total light capture. The above is not true. At equivalent f-number the light intensity at the sensor will be equivalent, but the total size of the FF sensor is 4x the size of the M43. So the total light capture for FF is 4x. For the same MP count the light received by each photosensor, which correlates to SNR or dynamic range will be ~4 x in case of FF vs M43. Conversely for same photosensor size or SNR the resolution will be 4x number of pixels in case of FF. The reason a given shutter speed / f-number combination give the same pixel brightness betweeen formats in the image files is that the electrical gain is calibrated to do so. Or effectively the ISO is higher in the case of the smaller formats and the noise is greater. You only have to look at the size of front lens elements to see that FF 100mm f/2 gathers a lot more light that M43 50mm f/2.

    “Studio work, where apertures are typically f/8 to f/11 for full frame users to get a person’s face completely in focus. With the smaller format, you can use strobes at 1/4 the power as the full frame user can, allowing for flashguns instead of studio strobes, or faster recycle for the same strobes”

    Again, not an appropriate comparison. If the DOF is the same between formats, eg f/4 for M43 and f/8 for FF ( which the corresponds to the same physical aperture size), the total amount of light reaching each sensor will be the same. All else being equal this means the SNR will be the same at the same flash output. 2 stops lower flash output requires more electrical gain (ISO equivalent) for M43 which increases noise and lowers DR. So the appropriate comparison is the same flash output at 2 stops greater f-number (same physical aperture size) for M43 vs FF.

    What IS true and is correctly pointed out is that for same DOF, all else being equal, the intrinsic image quality can be the same between format sizes. Note this requires smaller f-numbers for the smaller formats and hense ISO setting to be correspondingly reduced. In the studio there is flexibility to achieve this, assuming the M43 lenses are large enough max f-number. For many outdoor shots such as landscapes, DOF is not such important considerations and FF will almost always then provide SNR and DR advantage.

    1. Jordan Steele

      Paul – I agree that if you are using crop factors to compare lenses between formats for your own use, that’s not an issue. This article speaks to using crop factors to define lenses made for smaller formats as if shallow depth of field control is the only meaningful metric.

      Anyway, to your points:

      “The above is not true. At equivalent f-number the light intensity at the sensor will be equivalent, but the total size of the FF sensor is 4x the size of the M43. So the total light capture for FF is 4x.”

      What I wrote IS true. I touch on the point you make following on Page 1. Yes…the total light capture is 4x…that does nothing to the f/stop. It doesn’t change a micro 4/3 lens or APS-C lens and make it have a slower f/stop. My whole point is that the differences in sensor noise are inherent in the format…there doesn’t need to be harping on the light gathering ability as an absolute, as it only applies when you want shallower depth of field than the smaller format lens can provide. When you want the same or greater depth of field than the smaller format lens can provide wide open, then the 4x light collection advantage of the full frame sensor disappears, as you must stop down two stops more (or 1.3 stops more with APS-C) to achieve the same depth.

      “Again, not an appropriate comparison. If the DOF is the same between formats, eg f/4 for M43 and f/8 for FF ( which the corresponds to the same physical aperture size), the total amount of light reaching each sensor will be the same.”

      Yes, though performance will not be the same unless the sensors are of the exact same design and with the same efficiency, which they are not, but ok…

      ” All else being equal this means the SNR will be the same at the same flash output. 2 stops lower flash output requires more electrical gain (ISO equivalent) for M43 which increases noise and lowers DR.”

      This, however, is incorrect. If you are using the same flash output with the same depth of field settings, then the full frame camera will need to have ISO set two stops HIGHER than the m4/3 camera in order to achieve the same exposure because it will be stopped down two stops further to match the depth of field of the Micro 4/3 kit. If you can shoot at base ISO with your strobes, and recycle time is sufficient, and you have enough power, yes…the full frame kit will still maintain its advantage, but Dynamic Range is not one of them. As mentioned, modern APS-C and m4/3 cameras can match MANY modern full frame cameras in dynamic range at base ISO. The OM-D, for instance, has wider DR at base ISO than the 5D Mark III or the 1Dx. And noise at base ISO, while certainly cleaner when pixel peeping on the full frame camera, will not be visible in a print until you start passing around 30-40″, so that advantage is essentially irrelevant in the studio. So, for all intents and purposes, you simply require more flash power and slower recycle times to shoot full frame in a studio…there is limited advantage except for those who print very large. If this is you, then that’s fine.

      “For many outdoor shots such as landscapes, DOF is not such important considerations and FF will almost always then provide SNR and DR advantage.”

      SNR yes, DR no (as mentioned above). But yes, I agree that for many situations, full frame is definitely the superior format. This article is not saying that smaller formats are equal to full frame in the image quality department in all ways…they are not (though the circumstances mentioned in the article present many situations where they can equal the output due to light limitations and the use of faster apertures for the same depth of field). This article was basically a response to many rude comments and e-mails I’ve received that present a very flawed argument: Lenses for smaller formats should be considered solely in terms of the aperture that gives the equivalent depth of field wide open on full frame.

      1. Sascha

        “What I wrote IS true. I touch on the point you make following on Page 1. Yes…the total light capture is 4x…that does nothing to the f/stop. It doesn’t change a micro 4/3 lens or APS-C lens and make it have a slower f/stop. My whole point is that the differences in sensor noise are inherent in the format…”

        That is tendentious. The smaller format doesn’t change the focal length, too, so why talking about 150mm of 75mm? The smaller field of view is inherent in the format… no need to talk about it. But then there is no need for an article at all, because in the end all the points made by you are “inherent in the format”.
        To give an equivalent F-Stop is the easiest way to understand why fullframe has a lower SNR. And it is necessary to understand other phenomena, such as diffraction.

        As I said before, you are right with your intention and your conclusion. But some of your arguments are just wrong. The quoted above is one of them.

        1. maksim images

          Yes, FF do collect 4x more light, no one is questioning it. But it is also dispersing this absolute quantity onto 4x more of area which then again is negating any absolute light collecting gain per sq.mm.

          SNR is smaller in FF because photosites are larger due to lower pixel count per sq.mm; or in another words, if you had 4/3 sensor of 10MP and FF sensor of 40MP their SNR would be identical for same f stop.

          That is exactly why 4/3 (actually a bit smaller) 4MP sized sensor of blackmagic cinema camera is destroying 5Dmk3 as seen on this review: http://vimeo.com/49875510

          1. AskB

            So, if FF collects 4x more light this should mean that I can use shorter shutter speeds on FF?

            I have problems with long tele where 1/125 * f/2.8 is not enough. I can’t afford a larger tele but I have considered getting a crop camera for more reach, but I might as well get a tele converter instead then?

  51. Guest

    You didn’t mention one important “equivalence” topic. )
    Let’s put 2 cameras of different size sensors in “equivalent” situation. For example, APS-C NEX-6 against m43 E-M5. Let’s say they are using same field of view lenses with same aperture – which means both sensors get same amount of light per 1 mm2.

    Now, coming to sensor size (info taken from dpreview specs).
    Camera: NEX-6 | E-M5
    Sensor photo detectors: 16.7M | 16.9M
    Sensor size: 23.5 x 15.6 mm | 17.3 x 13 mm
    Calculating sensor area: 367 mm2 | 225 mm2

    Let’s calculate sensor area ratio: 367 / 225 = 1.63
    So, since pixel count is similar, this means m43 sensor’s pixel density is much higher, and that normally means photo detectors on m43 are smaller, so 1 photo detector on m43 receive 1.63 times less lights then on APS-C.

    So, the question here is:
    1) Is Sony “stupid” that they don’t put 16.9 * 1.63 = 27.5 megapixels in it’s camera to match E-M5’s pixel density
    OR
    2) Is Olympus so “smart” that they put more than 16.7 / 1.63 = 10.2 megapixels in it’s camera that would match NEX-6 pixel density
    ?

    1. David

      You want a Nokia 808….
      One day we might have a 120MP full frame sensor with in-camera sub-sampling. Might cost a bit however and the lens won’t be good enough.

  52. Paul

    Jordan,

    I will stand by my comments which relate more to absolute comparisons between format sizes rather than specific camera comparisons which may have different generations of sensor technology. Your points are valid in that the FF advantage may be less significant in practice due to many other factors. And in other areas like the a ability to manufacture advanced lenses with smaller elements in non-retro focal designs is an area where the smaller formats have advantages over FF. So the SNR benefit may be fully or partially outweighed by other factors. Would like to see more M43 lenses of at least f/2 I order to get DOF control and light gathering comparable to FF f/4 or greater lenses. Also as we now see diffraction starting two stops lower f-number than FF ( I.e. at same physical aperture size) I will be looking for at least f/2 max in order to get a usable range of aperture in M43. And I will compare these with f/4 FF lenses for the reasons stated above.

    As mentioned, I take most shots as the smaller formats sizes but still use FF for critical work. With f/2 and above M43 lenses ( lower max f-number) the size / weight advantages and the real benefit of being able to review shots in a diopter corrrected EVF will lead me to using M43 more and more over my FF gear.

  53. Iris Cook

    What a great article – and relief. I almost got a real inferiority complex listening to all this people praising their fullformat cameras. Now I can shed that…..
    Thank’s a lot!

    1. maksim images

      All you need is to go for mountain hike/photo walk. You will loose that inferiority complex before first summit.

  54. John Leslie

    I’d like to make a couple of comments you might like to consider, just for the point of interesting debate. As a point of reference I shoot Canon FF and m43 (plus an RX100 until its accident yesterday, still gutted on that one). I like both, FF for picture quality (the big pixels really do add some nice intangible something to the photos) and m43 for portability (although the long lenses are still lacking if you want AF, the 100-300 is really not good away from the short end unless used to post down-sized pics in forums, but at 5″ long shows what is possible with the format).

    Firstly saying the E-M5 has better dynamic range than the Canons is misleading and probably worth a caveat. Canon have always worked on getting good high-ISO DR in their sensors (which everybody seems to ignore for some reason on non-Canon forums and just slag them off at base ISO). For example:
    http://www.dxomark.com/index.php/enяŸНТЏяŸНТŸяŸНТН/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/(appareil1)/836%7C0/(brand)/Canon/(appareil2)/793%7C0/(brand2)/Olympus/(appareil3)/753%7C0/(brand3)/Canon#tabs-2
    So if you chuck in two stops of extra light gathering the FF Canons would always be ahead. Although I’d say that is a little silly way to compare them and the small amount of extra DR at base ISO on an E-M5 is a good thing. BTW it’s also a slippery slope, my RX100 has more DR than the E-M5 at their lowest ISOs, so perhaps everybody should go to 1″ sensors instead… or perhaps not.
    http://www.dxomark.com/index.php/enяŸНТЏяŸНТŸяŸНТН/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/(appareil1)/836%7C0/(brand)/Canon/(appareil2)/812%7C0/(brand2)/Sony/(appareil3)/793%7C0/(brand3)/Olympus

    Secondly the reason 35mm film is the standard is that was what the world used. When I was young I knew one person who shot MF but all my friends who were into photography got 35mm film cameras. Try buying MF (or APS, etc.) film in a kiosk at a tourist spot today (or MF with use of a time-machine allowed). Even these days you have a good shot of getting 35mm film. Also I think it is a very handy comparison point because of compact and phone cameras with their endless selection of sensors. How else do you decode what an 8.8 mm lens on a 1/3.2″ sensor means? I do find it odd the way some m43 users seem set against a handy comparison method that really doesn’t intend to have “implications” about what’s good/bad tagged along with it.

    Also on depth of field the full-frame cameras can always stop down to get more, the smaller sensors can often not just go to a larger aperture lens to get less. Plus very wide aperture lenses sold at prices suitable for m43 users aren’t great wide open if you want sharpness (although you may not). The key differentiator is that and when diffraction starts, as FF can go to a lower f-stop due to bigger pixels (even a D800 has about half the pixel density of the EM-5). You get a bigger range of “nice” f-stops on FF (say f1.2-f16) over m43 (whether for DoF or light gathering). The m43 advantage is DoF for exposure at a particular ISO, which is handy, although the FF user can crank the ISO to make up for some of the lost exposure. (Also isn’t ISO an annoying number, as it’s just a measure of how much the camera maker has to amplify the sensor signal to make the exposure work out for a particular f-stop and shutter speed, rather than being any kind of absolute, hence is completely sensor-related.)

    Do note on light gathering it is again wrong to say the E-M5 is all that close to the FF Canons (really not a fan-boy of any camera system, e.g. just recommended Nikon to a friend as was best for what they wanted, just responding to what you wrote with things to consider). In low-light the last thing you are likely to do is shoot at base ISO.

    BTW I did like the strobe cycling point, although with decent strobes the difference is fractions of a second. For example less than half a second min-max for an Elinchrom BRX250, and the f-stop change for DoF equivalence won’t get you half that in difference so I doubt it would matter. Flashgun recycling is more interesting and again worth a mention, although at studio distances (usually really close) the Canon/Nikon GN > 50 flashes only need a small part of their energy to light a model so more relevant outside at distance.

    One last point, for most of its life m43 has had sensors that lagged behind most of the other players. Picking a point where it has finally made a leap forward (with the E-M5 and GH3) to compare it with others is maybe not that representative. Perhaps doing it over a period of time would be. It’s well-known that Canon is coming to the end of their current sensor manufacturing methodology and so are a bit behind at base ISO at this exact moment. This is unlikely to be the case in a year’s time so diving in just now and ignoring the history or future is perhaps non-ideal.

    That’s not to say I won’t get an E-M5, I am considering it… (I’d already have a GH3 if it was GH2-sized). I’ll still shoot FF for when it really matters though. But the best camera is the one you have with you…

    Having read the comments (mostly from m43 users, I might be unpopular, but really just writing stuff for people to think about) I’d add:

    P.S. CoC is related to pixel size if you crop (as is often the case shooting with prime lenses when you can’t move closer/further due to physical or time restrictions), as print size/sensor size ceases to be the limiting factor if you don’t print the whole image.

    P.S.S. I’d argue against lp/mm being a useful real-world sharpness indicator, as for the same-size print the (for example) centre part consists of more mm of sensor on a FF sensor. Hence per picture height is more useful, IMHO, for viewer perception.

    1. Jordan Steele

      Thanks for your comments. As to your RX100 comment – I’m working on my review of the RX100…I was very impressed. There becomes a point for every photographer where the tradeoffs in size start to matter…for some it’s at full frame, for some it’s at APS-C, some it’s 4/3, and for some it would be at 1″. 4/3 is a nice sweet spot for me, but I understand everyone is different. But for those who would just grab an E-PL5 or a Rebel with kit lens and not add any other lenses for further functionality? I’d recommend the RX100 to them without a second thought. In fact, I have already.

      1. John Leslie

        I have a tip for your RX100 review – recommend users don’t drop it from 1 m (or 1 yd, I didn’t measure it exactly) onto concrete, as it can lower the subsequent user experience, plus possibly lead to a short-term increase in alcohol consumption. As far as I can see the only issue is the zoom lever is very hard to move, so far everything else looks okay. I am leaving pulling it apart until I’m fully calmed down though… Really gutted… (I had the wrist loop around my wrist, but it got knocked away from me and so – I assume – it got pulled off my wrist before that annoying Mr I. Newton’s invention took over…)

        BTW the Fuji XE1 with the zoom is also nice, although I found the viewfinder isn’t as good as the E-M5 with camera motion (which I assume is down to the circuitry driving it, rather than the EVF itself). The video modes are a lot less good than those on the RX100 and the AF, while improved, can still go walkabout on occasion. For still pics when you don’t want a long lens option it is very nice though. (Though a 55-200, err 80-300?? is planned, if it’s as sharp as the current zoom they may be on to something.) I still think I’ll favour m43 as my smaller interchangeable lens camera system for now though.

    2. John Leslie

      For anyone else reading this, on the DXO links you need to go into the comparison and choose the Measurements -> Dynamic Range Tab. I just copied the links from the browser title bar and they don’t go far enough, sorry…

  55. Isis

    “The OM-D E-M5 is only about a half a stop behind the Canon 5D”

    What?! EM5 is half a stop behind prehistoric 5D??? Maybe in 100 years 4/3 can match the 5D LOOOOL

  56. Isis

    I have now read a lot of it.

    1. I want my time back.
    2. You’re a HUUUUUGE Micro FourThirds fanboy!

    1. Jordan Steele

      1. Whoosh
      2. Whoosh – if you honestly believe that, you didn’t read the article carefully. And while I use m4/3 as my primary system, I think it’s pretty crazy to think I’m a fanboy. For MY shooting, m4/3 fits me best, as it meets my image quality and capability requirements while remaining small, lightweight and compact. In no way do I think it’s right for everyone. What camera system you choose is a personal decision, based on your photographic needs, your ergonomic considerations, your budget and so on. I shot Canon APS-C DSLRs for five years. I shot Canon 1-series APS-H and full frame DSLRs for 3 years, along with a full complement of the very best Canon L lenses (I have owned at one time or another, the Canon 24 TS-E, the 17-40L, the 35/1.4L, the 50/1.2L, 85/1.2L, 100/2.8L Macro, 135/2L, 200/2.8L, 70-200/4L IS, 70-200/2.8L IS II, and 80-200/2.8L). I still have a 1Ds Mark II with a 50/1.4 for those few times I really want that look it can give me that I can’t get with Micro 4/3.

      I know EXACTLY what a top flight full frame kit can do. I know exactly where it has serious advantages, and I know exactly where it has serious DISadvantages (mostly in size and weight, but there are other things as well). I’ve now been shooting Micro 4/3 exclusively for about two years, and I love it, but I also understand its limitations as well. If a better system to fit my needs comes along in a few years, I may very well switch to that. I do not have a huge amount of brand loyalty, and I especially do not have loyalty to a format…I use what works best for me, as every photographer should.

      I’ve got a Fuji X100s on pre-order, and that will become my main ‘one camera/one lens’ solution when it is released. Will I be a Fuji fanboy then?

  57. Steve

    Really great article.When it is pointed out that a 45mm MFT lens has an equivalent field of view to a 90mm full frame, it is not saying that the two lenses have identical characteristics. More over, the depth of field of a lens is not tied exclusively to its focal length. Consider three different 45mm lenses.
    The Lumix 45mm macro has an extremely short DOF, at short ranges, but infinity focus at normal distances.
    The Olympus 45mm f1.8 has a shallow DOF at mid range (portrait) distances.
    The Lumix 35-100mm f2.8 zoom has a longer minimum focus distance, and produces nice bokeh in long images.
    If you know your lenses and how to use them, you can get superior images with the smaller sensor.

  58. Raymond Holt

    Many thanks for this interesting & informative analysis!

  59. Joe Ogiba

    The big advantage of full frame is with fast wide angle lenses for a shallow DOF . Here is a shot with a Canon 6D with 35mm F1.4 Sigma full frame wide angle :
    http://farm9.staticflickr.com/8505/8436850517_d31750c918_k.jpg

    1. Jordan Steele

      Quite true. Nothing native to get quite that shallow, but m4/3 does have the 17.5mm f/0.95, which gets pretty close. The first one is at f/1.2, though I was still able to shoot this at ISO 200 due to the IBIS in the OMD.

      http://admiringlight.com/blog/wp-content/uploads/2012/08/brent.jpg

      http://admiringlight.com/blog/wp-content/uploads/2012/08/chloe_mirror.jpg

      1. Joe Ogiba

        I have the 25mm F0.95 version for my GH2 and know how great that combo is but I still think it’s hard to beat a full frame with fast wide angles. Here are a few more examples of the 35mm F1.4 Sigma with full frame sensor:
        http://farm9.staticflickr.com/8367/8433229049_719d056499_o.jpg
        http://www.flickr.com/photos/m4thi3u/8438547103/sizes/k/in/pool-2064616@N24/
        http://farm9.staticflickr.com/8466/8390479864_2f5866653b_o.jpg

        1. C.

          Yes, but by the same reasoning then you should go to a medium format camera with a fast wide angle …. in my opinion different formats have different strength and weakness for different assignments. For example, the big advantage of APSC is with pictures of small birds at a distance: you have deeper DOF and greater magnification with the same focal length, so you have to carry a smaller weight with you and so on.

          Thanks a lot to Jordan.

  60. Xavier Paris

    I am glad I found this web site !
    I have recently switch from Nikon to Panasonic, for many reasons ! Three of the main reasons are weight, space and price ! I first tried with the 45 macro lens to play around while walking my dogs. I did not want to carry the big, bulky, heavy Nikon equipment. I am not an expert in macro shooting, just wanted to have fun and the results i obtain were more than satisfying. then Panasonic announced the 12-35 and the 35-100, zoom with an unique aperture of f/2.8. As you know all, the 36×24 equivalent of these lenses are 24-70 and 70-200… Lenses I was using all the time. Few things I want to point out. I do not care if my 12-35 is really the equivalent of a 24-70 but it is close enough and what I see is that the pictures I get from it, either on my GX1 or my brand new GH3 are way more than great. I do NOT regret the switch. I get what I want and I love it ! I have great pleasure of using the 35-100 with which I get even better quality pictures than with my Nikon (I am not a nerd in technology, I know what I want and am extremely satisfied with both my panasonic zooms)
    One thing I want to say: I had the chance to compare the amount of light coming into my GX1 & 12-35/2.8 and into the Nikon D700 and the 24-70/2.8. I had set both lenses at 2.8, at 200 ISO and I got the exact speed : 1/160 of a second. As for the blur, not much of a difference, maybe – I haven’t noticed any differences, but as I was getting the exact same amount of light, I am sure the DOP is about the same (which is very well explained in this web site.) A F/2.8 stays a f/2.8.
    Anyhow, I have a brand new camera gear that is way lighter, cheaper, smaller, that gives me what I need and I love it ! I was daily carrying only two cameras and two lenses, with one flash, now for less weight, I have three cameras, my two zoom, a macro lens and a 100-300 zoom and one flash (I am not fan of flashes, it is just in case!) plus extra batteries….
    For many years, when the Nikon D1 came out, I heard so many things that were – I say it – stupid and I was the only one to say that a 300/2.8 stayed a 300 but with the framing of a 450… Time gave me reason.
    One thing you all have to keep in mind, is that it is not the camera that makes a great picture (Henri Cartier-Bresson was using a small 24×36 when lots of photographers were using 6×6). I saw so many so called photographers, even to this day, carrying big stuff thinking they’ll become the new Erwitt, Doisneau or Cartier Bresson. I recently was mocked by colleagues looking down at my equipment, until I show them the pictures I was getting. They stopped laughing at me. I saw the french photographer Marc Riboud once using a disposable film camera.
    Enjoy taking pictures whatever the camera, we have this saying in France : “Qu’importe le flacon pourvu qu’on ait l’ivresse” Alfred de Musset. (translation : never mind the bottle, let’s just drink it ! – bad official translation) whatever you drink from, as long as you get drunk ! And whatever you shoot with as long as you get what you want !

    1. Xavier Paris

      Sorry for my poor english, I am french ! Sorry for that too

  61. David Foster

    Thank you for an article that is informative, sensible, reasoned and reasonable.

  62. norm

    very good article to clear up misconceptions. But really too bad that so many have to compare “this is better than that” or “mine is better than yours”. Each individual buys what works for them, be it size, price, or use, and that should just be respected. Should actually get away from “equivelant” anyway, and just know the wide or telephoto number for whatever you use (like my 9-18 seems very wide and who cares what that is on something I don’t own). A great number of these new photographers never grew up with 35mm SLR’s anyway. Mines’ good for me and I’m glad yours is good for you, now let’s go enjoy taking pictures. How many pros put down amateurs, comparing their medium format or 8X10 box…..

  63. David Cartagena

    Hi Jordan.

    Great article. I use a 35 mm Sony a900 and totally agree with you.
    I came from Film 35mm DSLR to APS-C and then back to what I call Full Frame. I must admit that I find there is more advantages to a FF camera than to an APS-C 4/3 or whatever smaller or larger format.

    1. Lower noise.
    2. Greater DR (mostly)
    3. Shorter DOF
    4. And a thing I did not see mentioned in your post, a larger viewfinder. It has to be said though that on the new Sony SLT’s a larger viewfinder cant be count as an advantage to a Full frame 35mm camera any more since they have an EVF and can implement a similar seized viewfinder on any camera regardless of sensor size. There is still one advantage and that is the lower noise of an FF sensor and because of that a better rendering of the scene when looking through the EVF in low light.

    Kind regards

    David Cartagena

  64. Peter Caulfield

    Hi Jordan,

    Great article. I use micro 4/3 but I also still use 35mm film. I sometimes use my Nikon and Olympus film camera lens on my Olympus pen via adapters, a 35x105mm gives me a angle of view of 70x210mm which makes it great fun to use these old lens.
    In 1961 my Grandmother gave me my first camera a 120 box camera, my Uncle who had his own darkroom showed me how to develop and print my film. He would not use 35mm he said the negatives where to small,
    But I remember he bought a 35mm range finder in the 1970s because he could carry it every were he went.
    I went digital in 2002 but kept some of my film gear because I like the feel of winding the film, taking the photo and waiting to see the results when I get the prints.
    But the 4/3 12.3 mp images are much better than my scans from slides and negatives.
    I am sure some people will argue about the merits of larger sensors as long as there are cameras, but for me its the joy I get from the hobby and unless you are a professional photographer and make a living from it,
    It is the best hobby there is

  65. Andrew Nowakowski

    this blog reminded me that i got into this system (m4/3) for particular reasons and that i wouldn’t be able to replace my camera’s purpose with a full frame dslr. thanks for the added knowledge and reality check .

  66. stano

    Thanks for the nice reading. I agree with most of presented info. I like OM-D and m43 lenses, I prefer it mostly for their lightweight and size. The equipment its much more portable. FF I prefer for low light, shallow DOF shooting, for high resolution studio or landscape images. Also for sport where short shutter, good tracking AF and often also high ISO is needed. I would be very glad to have lightweight FF equipment.

  67. Bumpy

    Terrific article, many thanks.

    Perhaps as a follow up to excellent image capture explanation you could cover sensor to print (pixel density/sharpness, apparent dof, compressed dr, etc.)?

    Few comments:

    The concepts are challenging, should be no surprise marketing leverages confusion and many lack patience to understand. Thanks for trying to enlighten the impatient.

    Still, comparison is valuable and “1” must be set by convention (in absence of a natural unit measure). That 35mm is conventional “1” should be no surprise to anyone who knows history of amateur (mass market) photography.

    Ultimately those who really want to understand get value from having comparative measure. Consider how much knowing EXIF can help in understanding (learning to emulate) images you like. If you don’t understand, can only emulate with same equipment (and only slavishly), if you understand and can convert you can learn a lot from images made by people who use systems you have never tried.

    You can add birds to list of cases where you want fast shutter but not too shallow dof, plus often using 500mm or longer. I had been craving mirrorless ff until reading your article made me realize losing dof for less noise at high iso may not really be the tradeoff I want. Funny how photography is all about managing tradeoffs, and yet so many seem to insist on absolute superiority (of their favored system). Perhaps ignoing the absolutists would give you peace of mind – after all an absolutist is missing the tradeoffs and therefore missing the thinking part of photography.

    Cheers,

    Bumpy.

  68. Jairus

    Fantastic article! Agree with the comment that it’s the gear on his topic anywhere I’ve seen on the web.
    Very well written.

  69. Kim

    While I agree with your points in general terms, I think there is a resurgence of the equivalence discussion coming (if not already here) because the FF prices are dropping quickly and it is already very reasonable to choose between a D600 and an OM-D with grip, with only a 33% price differential. That brings up the dramatic difference in potential with almost 2 stops of SNR difference and definitely two stops of subject isolation difference at the same aperture. There is a sacrifice to be made for miniaturization, and there is no stopping the debate by sweeping it away with comments like “why bother looking at a format you don’t use?” The answer is “because you just might choose to use it at current prices so it pays to know what you gain versus what you lose.”

  70. Bruce

    Thanks for the informative article. I’ve posted a similar thread on an established photography forum which pretty much branded me as a heretic! The use of “full-frame” equivalents (FFE) is simply a crutch to help those familiar with the 35mm form factor to understand and contrast camera specifications and capabilities – much like those who still need to convert from Celcius to Fahrenheit to understand temperature values.

    It’s time to modernize as the number camera users who have never used a 35mm camera is likely to soon surpass the number that have (if it hasn’t already). Using these unfamiliar equivalences based on an arbitrary, antiquated technology is, for many, simply more confusing than helpful. It’s really only meant to make life easier for us old farts who don’t like change.

    Personally, I’d like to see comparable specifications that can stand on their own adopted in addition to noting equivalences. Other lens-based systems (i.e. microscopes, binoculars, spotting scopes, etc.) have – why can’t cameras? There must be calculatable, comparable specifications that can be used without having to return to the analog age for reference. FFE will slowly fade, as has use of the35mm film cameras from which it was spawned.

    1. Ahem

      Ironic how you lament the use of FFE, yet in last paragraph you suggest the introduction of a new standard, which amounts to what FFE is. FFE is a useful way for everyone to compare different formats, and doesn’t require experience with 35mm cameras.

      Introducing yet another metric would just mean everyone already familiar with FFE would have to learn a new method. So it doesn’t bring any improvement to the table for those unfamiliar with 35mm cameras – they either have to learn FFE or the New Method -, and only serves to confuse you old farts.

  71. Kevin

    I like your point about the benefits of more depth of field to begin with, in that a lens for a smaller sensor could be shot wide open to allow enough light come in, and at the same time get what you want in focus.

    But at the end of the day a larger sensor is still better – it gives you more control. For example I shoot an indoor portrait with m4/3 and an FF camera using a 25mm f/1.4 and a 50mm f/1.4 lens, respectively. Say on m4/3 I shot at f/1.4 and ISO800, and on FF I need to shoot at f/2.8 to get what I want in focus, and to maintain the same shutter speed as m4/3 I’ll need to crank up the ISO to 1600. Well, given equally good sensors, I’d get the same amount of noise from m4/3 at ISO800 as I would from FF at ISO1600

    But having more control using FF comes at the cost in size and price. Then you now have APS-C mirrorless cameras like NEX or NX that cost similar to m4/3, same sized, and with more control!

    That’s exactly why the original 4/3 format never got popular; it was similar in size to APS-C DSLRs and cost the same too. m4/3 is going to do well for now because it basically pioneered the mirrorless concept, and is a year ahead in terms of lens line-up. However a couple years down the line when several APS-C mirrorless system lens line-up are complete, m4/3 will be as pointless as 4/3.

    That being said, with sufficient advertisements and marketing, your average joe will never know/understand the difference. That is how Nikon 1 somehow survived

    1. Kevin

      And if someday FF cameras can be offered at the same size and price as APS-C, then APS-C would be pointless too.

    2. Alan

      “That’s exactly why the original 4/3 format never got popular; it was similar in size to APS-C DSLRs and cost the same too. m4/3 is going to do well for now because it basically pioneered the mirrorless concept, and is a year ahead in terms of lens line-up. However a couple years down the line when several APS-C mirrorless system lens line-up are complete, m4/3 will be as pointless as 4/3.”

      I doubt if any camera company including the DSLR market leaders, Canon and Nikon, have the ability to catch up with the range of MFT lenses available in one year. That’d mean developing how many lenses? In a year? It’s beyond them all IMVHO, and in some cases, like Canon, they have other problems that they probably need to look at too, like focus performance.

  72. Ahem

    You say: “This is about the use of full frame equivalence for people who have no reason to reference a format they don’t use, and against the far too often seen use of ‘aperture equivalence’ and how it relates to minimum depth of field as an absolute in determining the quality of a lens.”

    35mm equivalence is a useful shorthand even for those who have never used 35mm cameras. With the 35mm-e everybody has the same frame of reference when talking about different formats, instead of having to do rather complex arithmetic to agree on a common ground, or memorize crop factors and f-stop tables.

    Can’t believe this is still a topic in 2013.

  73. David

    Well written! I taught photography for years back in the film days, used 4×5 view cameras and lenses as well as 35mm gear. Today, I shoot with M4/3rds gear and love it – the weight and the quality are stunning! The best photographic tool is the one you have with you when the shot is there to be taken. I have also shot with “full frame and L glass, but my images today are every bit as good. There are even times when a little more grain (noise) yields a more engaging image. Again, nicely written.

  74. Richard

    I would like to point out that although a 50mm lens on my APS-C Canon 350D gives roughly the same FOV as a 75mm lens on a FF camera, the “perspective” is different. If both systems are used to take the same portrait from the same distance, the FF camera will give a more pleasing portrait picture than the APS-C with a 1.5 crop factor as the subject will be less “barrel-shaped” and “flatter”. That is my issue as I continue to struggle with APS-C vs FF.!! Thanks to everyone here for all the input.

    1. Jordan Steele

      That is not true at all, Richard. Perspective is dependent wholly on distance to subject. If shooting with an 80mm lens on full frame and a 50mm lens on your 350D, the images will have the exact same perspective (now, if your 50mm has a lot of barrel distortion, that’s one thing, but that’s a property of the specific lens you’re using and not the camera, though most 50mm’s don’t have barrel distortion).

  75. Gerry

    Great article!

    I have comment regarding sensor size/aspect ration and “Total Light”

    “Total light “actually is an effective number depending upon the aspect ratio of the FINAL product. In some cases a 3/2 ratio will be closer to the end product, in others, a 4/3 ratio is closer. Effectively, post processing cropping “discards” much collected light!

    A second note, “sensor generation” is absolutely correct to include in this article. Very shortly APS-C and 4/3rds (not excluding others less than full frame)senors will have all the sensitivity, low noise and dynamic range 99% of photographers need and some of the 1 % (let’s not argue actual percentage, just it is small) may not make it with even full frame.

    Finally, it is far lower cost to make very high quality small format lenses that equal quality larger lenses. One issue not discussed but important to a few is diffraction .limitations of small systems. That get’s very complex but affects few photographers.

    I believe the next generation of sensors (late 2013-2014) will make full frame or larger all specialty products for those with unique requirements an a very thick wallet ;-)

    1. stando

      regarding abilities of current sensors:
      I can’t agree that current m43, APSC or even FF sensors are good and almost nobody needs better sensor. I think we just used to accept sensors limitations and found ways how to compensate them by some degree.

      I would be really satisfied with the sensor technology if it would match ability of the people eye. If we would not need to use flash for indoor scene shots at normal artificial light (with shutter speed 1/125 or faster ) and noise level would be cca like ISO800 using current best APSC camera. Even with f2.8 lens it is often even ISO6400 not sufficient at 1/125 speed. And at such high ISO IQ could be only acceptable at lower resolution.
      Dynamic range ability is also quite limiting for sunny days with strong shadows even at low iso100. With higher iso dynamic range is falling very match. …. By far not comparable with what your eye sees.

      At the current progress of sensor development I expect that also in 10 years APSC or even FF sensor will not be capable to match peoples eye performance and will limit photographers.

      1. Mike

        In many ways sensors surpass the human eye.

        The eye/brain can easily miss significant events and is incapable of stopping fast motion, with the clarity acheivable by just about any modern camera.
        In very low light levels cameras can use longer exposures to pick out differences the eye can’t manage. Try reading a page of 10 point lit only by a candel 10′ away. A camera can record that page even using a 5 year old sensor.

        Cameras probably will never match ‘the eye’, as the eye/brain system is dynamic – building up an image from a series of sections, refocusing & changing aperture as required…

        If I had a camera capable of producing a high resolution, noise free image, at iso10000000, with dynamic range of 2^24, there would probably still be times I’d want a bit more. Not that it stops me enjoying using what I’ve got:)

  76. Mike

    Thank you for the excellent article. I am new to photography and trying to learn about the art. I am “technical” by nature, not creative and have a very good ability to grasp complex subject matter quickly. For that reason most books bore me to tears before I can get five pages deep. Reading your article, irrespective of “equivalency” helped me understand the synergy between the several variables required to produce a photograph in almost any situation. I believe I am now armed with the knowledge I need to understand how to assess an opportunity. Hopefully over time I’ll learn the art of properly combining them, but for now I am very appreciative to have the understanding you provided.

  77. lee Harris

    Thank you thank you thank you. I shot on film 35mm and 6/7 in the old days and the crap that gets talked by the Fool frame gang to justify their overpriced bricks drives me up the wall, I recently got rid of my DSLR and got 2 EM5s and the weight/space savings is incredible and the quality amazing, I firmly believe DSLR will be curios in about 3 years time, mirror less in most formats will be the norm. Canikon are dragging their feet and I think knocking out much cheaper Fool Frame cameras to trap a whole new user base who then will be locked into the systems with expensive lens purchases etc., but eventually Canikon will shift their complacent asses into the mirror less camp.

    And as a pro I can tell you most work requires more DOF not less, shooting heads shots with the 45mm at f1.8 is bloody tricky, thank god for eye recognition!

    1. Subramoniam

      Hehehe… Fool Frame gang is the apt usage for FF fanboys

  78. Subramoniam

    Great article. It cleared many a cobwebs I had about going in for a 4/3rd. APSC is breaking my back (disc prolapse).

  79. Simen1

    Regarding total light and efficiency of different sensor sizes take a look at the size-normalized dxo-iso scores in figure 6 at luminous landscapes article. http://www.luminous-landscape.com/essays/dxomark_sensor_for_benchmarking_cameras2.shtml

  80. Jon

    Your main point is a good one, and one that’s occurred to me a lot when reading forums or speaking to experienced photographers: “Full frame equivalent” field of view means absolutely ZERO to someone who’s never used a full frame camera. If an amateur photographer who has a crop sensor camera is thinking about getting a 35mm lens and you tell them that 35mm is equivalent to 50mm on a full frame camera, this means nothing to them if they’ve never used a full frame camera as they have no idea what angle of view that will give them. The only way it would be of use to them would be if you also explained that 50mm on a full frame camera is a very common focal length because it is very close to the field of view of the human eye. But if you’re gonna tell them that you might as well leave out all the full frame references and just tell them that a 35mm lens on their crop sensor camera will give them a field of view similar to that of the human eye.

  81. ??????

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  82. Andrey

    Well illustrated article!

  83. StefanoM

    Dear Jordan, I have to thank you many times… With your blog you helped me to get rid of the “full frame legend”. So, instead of buying a EOS 6D, I have sold my Canon stuff and now I am a happy owner of a OM-D E-M5… It is stuck in my everyday bag… much less weight/size and many more photos!

    Keep going
    Cheers

    Stefano

  84. GerHer

    Great article. I for one use cameras with different sensor sizes, FF(film), 1.6x, 1.5x, 2x, and various compacts, some of different generations of technology and for different uses, and I use the equiv reference to help compare what should I expect in the angle of the frame, after that on everything else I think of each camera as its own, since every one of them has advantages and limitations towards the others (noise, iso, dr, size/portabilty, features, IQ, DoF, OoF, focal lenght available, etc)

  85. Flavio E.

    The amateurs are so happy to find that micro 4/3rds give great results and start making up a lot of arguments on why Full frame is outdated, and/or too big, or unnecessary, and they ramble on on how 4/3rds or APS-C gives “equal” quality.

    While the professionals are already well into Full frame and in fact the pro gear is likely to move to BIGGER sensor sizes in the future…

    Contrary to what many people think, one of the reasons pros use BIG sensors is not only lower noise or shallower depth of field. The reason is optical.

    You can shrink sensor sizes but a lens optical system hits a limit of precision. Contrary to popular thought, very good medium format, full frame, and 4/3rd lenses [primes, NOT zooms] exhibit similar absolute resolutions (in line pairs per milimeter) and similar MTF curves.

    The difference is that, for an equal megapixel count, the BIGGER the format, the less line-pairs per milimeter demanded from the lens. This means that the lens will be needed to work in the zone of the MTF curve where the modulation is near 100%, where as smaller formats will make the lens work in the MTF zone further away from 100%. Read that twice please.

    This is the reason why in the past, given very good lenses, large format (4×5″) gives far, far better detail than 35mm and this is the reason Full Frame sensors still have an edge over 4/3rds sensor.

    But there is another related item: This also means that, to reach an equivalent definition, the larger sensor demands LESS from the lens. This is why a so-so zoom lens on a Full Frame camera can achieve equal or better actual detail definition than an APS-C camera fitted with a better quality lens.

    1. Jordan Steele

      Flavio, your argument has some theoretical merit…the problem is that it doesn’t bear out in reality. The lenses that are designed for these smaller formats are getting that extra resolution required of the tighter pixel density. Take lenses like the Olympus 75mm f/1.8, or the Leica 25mm f/1.4 or the Fuji 14mm f/2.8…among MANY more…and these lenses are performing as well and in many cases superior to an equivalent full frame lens on a full frame body. The Olympus 75/1.8 I would put up against ANY lens on ANY format for pure resolution. The kit zooms on micro 4/3 are generally regarded as sharper than their DSLR equivalents.

      The fact is, the native glass for these smaller formats is easily delivering (and in many cases exceeding) the resolution that the full frame systems are getting with their lenses. And while a full frame camera may demand less of a lens than a smaller format in the center, on the edges, if you’re adapting, they have to deal with the corner issues that a smaller format avoids when using the same lens.

      So, it’s a nice thought, but it doesn’t hold up in practice.

    2. Fri13

      Most used format today for system cameras is APS-C what is known from film era as “Half-Frame”.

      Today most used sensor size is 1/1.8″ or similar.

      Who wants to call small format aka 35mm as standard are idiots. They dont have anything for what to backup the claim, not the popularity, not the quality, not the history etc…

    3. Fri13

      That isnt actually true. Now and then there comes these claims that it is easier to make a sharper lens for larger format. That isn’t true. We can even go and take extreme examples like a lens for observatories or satellites and then lens for smart phones. The other lens is by diameter about 50-200cm (or even 500cm) and other is 1-4mm.

      Now to make the larger lens, it takes lots of time for polishing and very high quality glass to be melted etc. But smaller lens requires as well high quality glass and polishing but much less.

      Example, let’s look a Nokia 808 the original Nokia preview. 41Mpix sensor behind a ~4mm lens. Much better resolution than most APS-C or even some 35mm sensors has and with much sharper lens than Canon L lenses has etc.

      But why it is so? The flange distance.

      The light needs to be slowed down via lens to bend it. And when we bend it more, more optical power we have. And more we have, more the light will distribute larger area. Think about example the prism. You get all light colors from it, but further the surface where light is projected is, more distribution light gets.

      Smaller sensors allows tele centric lens design where light isn’t distributed to larger area, it gets less optical power requirements than larger sensor. And the light hits more directly to pixel than in angle like with larger sensors.

      And we have flange distance shorter where the “prism” projection surface is much closer to prism than with larger sensors.

      To make a sharper lens for smaller format, it requires less polishing, less glass, less optical power designs, less high quality glass overall and it is faster and cheaper to make.

      But, when demand is small, prices are high. Production is short and it takes as much workers as to design a large batch of other lens.

      It is bs that larger lenses are giving sharper results, if you can’t bring them as close to imagine sensor, you have no benefits.
      That is by optical quality limit to distance.

  86. Fotognut

    I think you should add a section about t-stops (transmission stops). while they’re generally associated with video, it would be a good point of reference, and could help people understand f-stops better.

  87. Shamael

    Today, when ever I read about cameras, new digitals coming out, there are only two things that seems to be important to those new upcoming photo freaks, what is DOF and the ability to produce low noise at 12500 ISO.
    When I was young, we switched from 35mm to medium 6×7 gear and even to chambers with sheets, to get a sharpness all over the field. The main reason is the body, the distance that the lens is away from the film. If you make the distance longer and make lenses to match that distance, you get better sharpness all over. Now, the medium format had this advantage what is a disadvantage when you consider body size. Look at fast Leicas and the distance of the lens to the sensor, and look at the bokeh. Now, the question is always the same. What do you want, what is your goal. Want sharpness all over for the family album, stay with smaller sensor, want bokeh and nice portrait shots, go bigger. For sure, you can get good shallow DOF with a small sensor by using a fast lens, but, as you wrote it, you can never get the same bokeh as a FF with the same fast lens. But, there are spacers that can do that, and, there are adapters that have a tread and you can turn in and out and adjust this. I have seen god shots from just any size of sensor, I use 4 sizes myself, and all is about what size you use for what shot. The ideal camera that does all the way you would like it to do will never exist anyway.

    Some of all those newbies should step back in time, take a Mamyia C330, a light meter, a 400 ASA and try to do the same job they do today on their PC and a digital. I think they are a bit too spoiled and they criticize all. I have lived times with no TV, no cellphone, no PC, and bikes you worked on for 4 days to be able to drive 2. Then, suddenly I realized that I could have fun with a Kodak Instamatic that my father bought for my birthday. I will never say that ancient times where better, one can’t compare, but, if you gave me the choice and we could do it, I would like to go back 50 years right away, but with my NEX and my PC only.

  88. Milos

    I prayed someone would write an article like this. Although I’m not a pro photographer nor do I aspire/want to become one, being a long-time amateur astronomer I have a reasonably good knowledge of optics, signal processing and the tech involved. I find it irritating when people speak in terms of these ambivalent equivalences. I can imagine that “full frame” will always stand its own when it comes to certain way of artistic rendering or large-format prints but technically all cameras are “full frame”. If you are after particular blurry look then yes, bigger is better but I can imagine just as many situations where having a larger depth of field is beneficial. As the dynamic range and signal-to-noise ratio of sensors improves, we will very soon reach a threshold when having a large sensor or slightly more samples per “web pixel” brings diminishing returns in terms of definition. I’m not implying professionals don’t know their tools, in fact, I think the sales of system cameras depend partially on their adoption by pros but as a concept, I think mirrorless cameras are great. It’s only a matter of time until someone introduces a “full frame” compact system camera and once the genie is out of the bottle, there’s no coming back to DSLR.

  89. Mark

    …but APS-C & FF lenses will still be bigger than m43 ones. Miniaturization of bodies will continue, however lenses are tied to sensor size and lens size & weight will soon become the critical factor of a system. Given that m43 seems to have hit a sweet spot in terms of image quality vs. lens bulk I see it continuing. I’ve had an OMD for a month (my first ‘proper’ camera) and already my non-photo nerd friends are commenting on the image quality from a ‘small’ camera.

  90. HF

    IMHO DOF gets overstated, at least for the non-professional. I own several cameras and usually use my Nikon D7100 APS-C with primes, however, DOF is often so shallow, that you get a butterfly’s eye nicely sharp, but its wings blurry and need to change distance or change aperture. I did some calculations as to determine
    the DOF for different focal lengths and apertures (rounded):

    2m distance to object:
    4/3 | 45mm 24cm(4) 17cm(2.8) 12cm(2.0) 11cm(1.8) 9cm(1.4)
    APS-C | 60mm 18cm(4) 13cm(2.8) 9cm(2.0) 8cm(1.8)
    (Aperture in brackets). It’s not so dramatic, considering the fact, that you don’t want to have only the nose of a person in focus.

    APS-C, 40 cm distance:
    Aperture: 1.8 2.8 4.0
    ———————————————
    90mm 0.1 cm 0.2 cm 0.3 cm
    60mm 0.3 0.4 0.6
    50mm 0.4 0.7 0.9
    35mm 0.9 1.4 2.0
    30mm 1.2 1.9 2.8
    ———————————
    First column focal length, DOF in centimeters.

    Changing distance to object:
    Aperture 1.8 2.8 4.0
    20cm | 35mm 0.2 0.3 0.5
    30cm | 35mm 0.5 0.8 1.1
    40cm | 35mm 0.9 1.4 2.0

    Based on: http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

    So it shouldn’t be a problem to get nice DOF using APS-C mirror less or m43 cameras by just changing distance or focal length, together with nice primes (which may be expensive). YOu even have advantages doing macro shots using m43.
    For professionals it may be different, but for the amateur it’s more than enough.

  91. Luiz

    So DOF…what’s the problem with full frame? If DOF is too shallow, get more aperture. Want less time? Higher ISO will be better. “…but now, the full frame camera has just lost ALL of its image quality advantages”? But: “Lower Noise. Full frame cameras of similar sensor technology to their smaller counterparts will yield lower noise images at its baseline…..”. So..?

    Come on, don’t explain yourself why did you buy m4/3. It’s simply. m4/3 is smaller. That’s it. And maybe better for video. There are many situations where the m4/3 beats FF, especially travelling.

    For studio, professionals etc. FF will always be important and useful.

    My opinion :-)

  92. Mike

    Page 1 was excellent, but page 2 is rather flawed. Just because a concept has no use to you doesn’t mean it’s useless.

    35mm film was the obvious standard to use in defining a crop factor. Not only was it by far the most popular at the time but the other formats in use by photographers we’re themselves not a standard size.

    Medium format includes 6×4.5, 6×6, 6×7, 6×9 & 6×12… sizes even if the film is all 120 (or 220 which is respooled 120), digital MF now adds more sizes too.
    Large format has 5″x4″ and 10″x8″ in its common uses but includes many others.

    IMO 126, 110 disc & APS-c film were used by snapshooters rather than photographers.

    I currently use 3 formats in my everyday shooting APS-C, micro 4/3 & a compact. So find crop factors useful when switching systems and wanting more than just ‘roughly normal’ / ‘mild telephoto’ type distinctions. It’s also helpful when looking at others photos on-line where without knowing the camera used in detail I can access the field of view…

    I don’t understand why ‘full frame’ is considered the ideal by so many. All the arguments in it’s favour apply even more to 645D, it takes the disadvantages further too (heavy/expensive…)

    If 35mm is full frame is 10×8 overflowing?

  93. kit laughlin

    Very nice article, Jman. And you probably know from FM that I have recently moved back to Fuji’s APS-C sensor, and many of the aspects mentioned in the article were part of the decision process. I have been a pro. shooter for 30+ years, and in the “olden days” 35mm (135 format) was consider a toy format by all the 6×6, 6×7, 6×9 and sheet film people. Times, they do change.

    One decision I applaud Fuji for is to make their primes in focal lengths that mirror the full frame equivalents: 14 (21mm EFOV), 18 (27), 23 (35), may all-time fave the 27/2.8 pancake (41 mm, the “true” normal lens for FF), and the 35/1.4 (52mm). And we are all waiting for the 56/1.2—there’s the missing 85mm equivalent. The reason I think these are good decisions is simply the convenience of having a spread of prime that history has shown will cover most situations.

    I am keeping at least one GX-7 simply for video and macro (the OM 50/3.5 is sensational on the µ4/3rd’s sensor. Great work.

  94. Christian

    I’m not getting it.

    From a physical perspective a lens with a 71mm aperture diameter (200mm f / 2.8) surely collects more light than a lens with a 6.4mm diameter (18mm f /2.8): roughly 100 times more energy based on the aperture surface. Of course if you spread that over a larger sensor that’s 10 times larger you’ll get the same energy per pixel. But then you’d get 100 times as many (mega)pixels. Generally engineers trade that off to sharpen the image and reduce noise etc. So there is a difference in quality even though both lenses have an f/2.8 aperture. That doesn’t mean there’s a linear impact.

    Taking an idiots approach I get better results with most large format cameras than most smaller cameras. Of course it all depends on the guy behind the camera, but the idiot in question (me) being equal there must be a difference in the optics.

    1. Jordan Steele

      An f/2.8 lens passes the same intensity of light no matter the focal length. That’s why if you take a shot with a 14mm lens and a 300mm lens at f2.8 in the same light, you get the same shutter speed.

      Remember that a 14mm lens pulls in a significantly wider field of view (more area of light) through that hole, while the 300mm lens captures just a few degrees.

  95. Christian

    Of course – You’re right! Smaller field of view – less energy. Thanks!

  96. arno

    Very nice article. Thank you for sharing.

    So, only by dividing by 2 (or any other crop factor) I can find the equivalent background blur in m4/3 ?

    I.e. If I replace my 24mm f4 on my 5d with a 24mm f2 on m4/3, or the 50mm f8 with a 50mm f4 , etc the background blur will be exactly the same? Exactly? Simply as that?

    If this is true
    a) why doesn’t anyone else right about it?
    b) can someone post samples of that?

  97. Arthur

    well done article, thx !

  98. Robert Mark

    Words mean things, which is why I object to the terms “full frame” and “crop sensor” as commonly used.

    When referring to the 35mm sensor format, it is always more accurate and descriptive to simply say “35mm”.

    “Full frame” simply describes a sensor which captures the maximum possible size image from a given sensor size and lens combination. Of course, a Canon 5D Mark III with EF mount lens fits this description. But a Canon 7D with its APS-C size sensor is also a full frame camera when paired with an EF-S mount lens, because EF-S lenses (which are few) create an image circle that is optimized for the APS-C size sensor. There is no crop of the image circle in any way with this combination.

    However, since Canon chooses not to make a full line of EF-S lenses, and since it is physically possible to mount the larger EF lenses on APS-C sensor cameras (everything from Rebel to 7D), one only uses a portion of the image circle, hence the derisive term “crop sensor”. A more accurate term would be “oversize lens”, as there is no cropping of the APS-C size sensor in any way, but one loses about half the image-making power of a lens designed for the 35mm format.

    Micro 4/3 never fits the “crop sensor” designation, because every Micro Four Thirds lens has been specifically designed with an image circle that matches the sensor size. Micro Four Thirds is most definitely a “full frame” sensor.

    Fuji’s excellent cameras use the APS-C format, but because all their lenses are designed specifically for the format, it is as surely a “full frame” format as 35mm is.

    The same confusion exists in other sensor formats. Medium Format is both larger than so-called full frame yet also a crop sensor in the current vernacular. Medium format lenses are designed for the 60x60mm film format, yet the best current sensors measure 44x33mm — most definitely a “crop” sensor if we use the term as it’s been applied to the smaller-than-35mm-size-sensor cameras.

    Let’s stop the “full frame” and “crop sensor” nonsense. A camera is simply 35mm, APS-C, Micro Four Thirds, etc.

  99. Reader

    An f/stop is a ratio of the front element of a lens to the rear element of a lens. A T/stop is a measurement of the actual transmission of light through the entire lens. Cine lenses are described by a T/stop. It’s a shame that lenses for still cameras are still specified by the f/stop, a measurement less useful than the T/stop.

    1. Fri13

      T-stop doesn’t give you depth of field ratios, it gives you only amount of light what changes by used glass in lenses etc. Like we can take two 50mm f/1.8 objectives from canon and Nikon. Bot give same depth of field at same aperture, but bot give different T-stop. Other can give T/2.1 and other T/2.4. So you can get two different exposure values for same depth of field.

  100. James Conner

    The author makes good points. A few observations:

    Instead of focal length equivalences, I prefer using the horizontal angle of view (easily calculated) for lens comparisons between formats.

    The notion of aperture equivalence has always struck me as confusing and not helpful.

    I do think photographers should be careful not to use the word “aperture” as shorthand for “focal ratio,” and not to use “f-stop” as shorthand for “aperture.”

  101. BananaJoe

    I am sorry but there is a point where your logic comes tumbling down. If you need more depth of field, you can also achieve it with a larger sensor: just stop it down more. If you need the same exposure as with a smaller sensor, raise the ISO by the same amount.
    135 is 2 stops better than M43, noise-wise, so M43 will never have an edge over it, not even when “one wants more DOF”, because the same DOF will require stopping it down 2 stops extra.

    1. BananaJoe

      …2 stops extra, not 3 or 4.
      On top of this, there is the magnification advantage, of which you make no mention.
      As it is only logical, larger sensor have better or equal IQ, and this can be demonstrated on paper.

    2. Jordan Steele

      It seems you did not read the whole article (seems to be a common occurrance). I specifically address this in the article. Yes, the newest full frame cameras are about 2 stops better than the newest micro 4/3 sensors and about a stop better than the newest APS-C sensors.

      However, equivalence is often thrown about as if it is universal to the format, which it clearly is not, as there are many APS-C sensors that are on par or superior to older full frame sensors. There are m4/3 sensors on the market now that are as good as old full frame sensors. It’s not a hard and fast ‘rule’, and therefore even this argument, doesn’t quite work.

      Then there’s the fact that if you’re constantly stopping down and raising ISO to compensate in this manner, you are simply carrying larger and more expensive gear for absolutely ZERO image quality advantage in those situations.

      There is not one point where I say that smaller formats have better image quality than a new full frame camera. However, speaking as if wide open depth of field is the most important criteria of a camera is also folly.

      Also, the ‘magnification advantage’ is an imaginary concept. It manifests itself in the other image quality parameters (predominantly lower noise), but is nothing on its own. Modern lenses designed for smaller formats are correspondingly sharper with the smaller area captured and will very often result in similar resolution to a great lens on full frame. Magnification means very little if you have the same resolution and a lens that can resolve the same detail corresponding to that resolution.

    3. Fri13

      Not 2 stops, it depends from sensor technology.

      Place latest m4/3 head to head in real world against Canon 5D Mk3 and m4/3 wins in noise quality.
      Take example E-M1 and place it against Nikon D800e in real world tests and do large prints and you do not see difference in same ISO.

      It is already a myth that 35mm has better noise as it is only possible see in lab tests or pixel peeping 400% enlargements from computer screen. Do a 3x4m print and you don’t see difference.

  102. BananaJoe

    Jordan, this is not a debate, I am not debating with you, I am just pointing out some errors. Since you are writing in a public place, you are supposed to correct errors, or openly state who sponsored you. Well, at least in a perfect world.

    Here is an error-crammed sentence:
    “Then there’s the fact that if you’re constantly stopping down and raising ISO to compensate in this manner, you are simply carrying larger and more expensive gear for absolutely ZERO image quality advantage in those situations. ”

    Error 1) Equivalent lenses are mostly (not always!) the same size across systems
    Error 2) Equivalent 135 lenses are mostly cheaper than 43 and M43 lenses
    Error 3) There is a residual image quality advantage to a larger format, there always will be. Other posters have already corrected you on this. I have seen you made no amends though.

    1. Jordan Steele

      I had a huge reply that I realized was sort of rambling, so I’ll try and be concise.

      You are pointing out ‘errors’ that don’t exist. That statement is true…if you are stopping down for more depth of field and increasing ISO to compensate for the smaller aperture you need to use vs. the smaller format, you have just negated the image quality advantage of full frame.

      Note, that in my article, I have an entire section that talks about areas where full frame cameras are superior with regards to image quality. No one disputes this. The article, however, address the folly of using blanket ‘aperture equivalence’ to describe smaller format lenses. This calculation can be used when you are truly trying to figure out what f-stops will yield similar depth of field between formats, but as an overarching equivalence it’s seriously flawed (for the reasons I address).

      You bring up ‘equivalent lenses’ and that’s part of the issue. There are very few truly ‘equivalent’ lenses between formats. They vary by each individual lens, and often, the lenses with slower apertures on full frame are nowhere near as optically corrected as their faster crop sensor brethren. So it’s a false equivalency.

      For instance, let’s examine the Fuji 56mm f/1.2 and the Panasonic Leica 42.5mm f/1.2. The Fuji has the same depth of field at f/1.2 as an 85mm f/1.8 would have for the same framing at f/1.8. The PL 42.5mm has slightly more depth of field, at around f/2.2 on the 85mm f/1.8. That much we can agree on. However, calling these lenses ‘equivalent’ to all full-frame 85mm f/1.8s is flatly wrong. Both the Fuji at f/1.2 and the PL at f/1.2 are SIGNIFICANTLY sharper and have lower CA than the Canon 85mm f/1.8 at f/1.8 (or f/2.2) on full frame. And it’s not even close. These are not ‘equivalent’ images. To get this kind of optical quality at 85mm, you need to spend a lot more for the 85mm f/1.2L, which is over double the cost of the 56mm and still significantly more than the 42.5mm.

      Now, comparing to Nikon’s new 85mm f/1.8…things are a lot more comparable…and in this case, the Nikon is cheaper. The point is, it’s a lens by lens comparison, and does not hold in any way across lenses in general.

      In the mirrorless game, there’s not a lot of full frame goodness…but look at the fast normals. The Sony FE 55mm f/1.8 is optically phenomanal…better than the normals for Fuji or Micro 4/3. However, you pay for that in size (notably bigger than those lenses) and price…despite not having too large a depth of field advantage. The few ‘equivalent’ lenses that are generally optically on par with the high end mirrorless lenses are usually quite a bit larger, or quite a bit more expensive. There are exceptions (the Nikon 85/1.8 being one of them), but it is enough to show that you can’t use blanket equivalence. There is no real full frame equivalent for the Olympus 75mm f/1.8, which is simply astounding optically right from f/1.8. Anything that is optically similar in the 135-150mm range is going to be the high end optic in a lens lineup, and will come in at notably more expensive and definitely larger than the Olympus. Again, it’s a lens by lens thing, and not a blanket equivalence.

  103. Sebastien

    Article feels like a long-winded self-justification why small sensors are good too. Hey, whatever floats your boat. You’re correct that smaller sensors tend to have better performance-per-area, which somewhat alleviates their inherent flaw – their size. At some point 3-8 years down the road we’re going to reach an efficiency plateau, making performance-per-area similar for all sensor sizes. At this point, smaller sensors just won’t be able to compete in any metric. Do you want to sell all your stuff by then? Imho, it’s much more sensible to chose a future-proof system now.

    1. Jordan Steele

      Smaller sensors already don’t ‘compete’ in any metric (for the same sensor tech) if you are talking pure imaging characteristics of the sensor. However, especially nowadays, that’s a bit if a moot point, and it will become more so in the future.

      We are at a point of diminishing returns already. Sensors will get better and better, but the improvements will be harder and harder to see. Any large sensor camera (and by that I’m talking 1″ and up) can already produce outstanding image quality, good enough for 24″ prints and any web use. The larger you go sensor wise, the better larger prints will look and the cleaner the files will be, but how many people are regularly printing larger than 30″ or shooting in extremely dark conditions? There comes a point where these improvements become very subtle for most shooting. When an APS-C sensor can have 15 stops of DR and clean ISO 102,400, what tangible improvement will you actually see by going with something ‘better?’ Some will still want that little extra edge, and that’s fine, but the justification for carrying larger and heavier gear will come down purely to optical characteristics desired for most shooters.

      I think having the ‘right’ camera for how and what you shoot, whether that be a high quality compact or a medium format digital beast, is far more important to getting the most out of your photography than having the ‘best’ camera.

      I had a full stable of high end full frame glass and a full frame pro grade camera before switching to mirrorless (First m4/3 and then Fuji). It would have been far easier financially to simply continue to upgrade my camera body, but I found carrying the huge kit had a negative effect on my photography.

      For me, the Fuji lenses are really about as large as I want to carry anymore. If the Sony FE line gets fleshed out with small high quality lenses in addition to fast ones, it would be an option, but there is a ton to be said for interface and comfort as well. Obviously, everyone is different, and if full frame fits your needs better, then that’s absolutely the way you should go.

      My next article will actually delve into these a lot more in depth.

      1. Sebastien

        I tend to agree with you. You should buy the best camera in the size range that you’re willing to always take with you. Have you tried the Leica M? I’m *over the moon* happy with it! The lenses are really small and the results are amazing. Have you given it a try?

  104. ?????? ??

    Superb blog! Do you have any recommendations for aspiring writers?

    I’m hoping to start my own site soon but I’m a little lost on everything.
    Would you recommend starting with a free platform like WordPress or go for a paid option? There
    are so many options out there that I’m completely overwhelmed ..
    Any ideas? Thank you!

  105. Patrick

    Outstanding article. I now have a solid understanding of this. It has told me that I made the right decision to stick with my crop dslr. I love it. (Nikon D7100).

  106. Konstantin

    Great article Jordan! I have made a similar statement on my blog after I realised the confusion that exists with crop factors in relation to aperture.

    http://www.konstantinknoblich.com/blog/2014/5/the-crop-factor-controversy

    I recently have seen a popular youtube photographer trying to convince people using “maths” how a lens is not what it says it is when it is on a crop sensor body. He was changing the physical distance of the focal length to match the equivalent distance of the full frame to get the f-number. This seems rather dishonest to me when a lens has specific measurements that don’t change just because of the equivalency argument.

    Anyway, nice to read about the S/N ratio and how we should keep in mind the difference in sensor technology before blanketing everything with the crop factor argument.

  107. Daven

    Great read! It seems there is never a shortage of things to say on this topic, nor a shortage of opinions, but you really hit the nail on the head with the bit about photographers already know the compromises they made by choosing a smaller format and that’s that.

    One thing I might add, though, is that manufacturers often try to get consumers to believe that their smaller format, wide aperture lenses are equivalent to full frame lenses at the same aperture. Nikon’s 1-series 32mm f/1.2, for example, costs $900—rather cheap compared to an 85mm f/1.2, yes, but ridiculously expensive compared to Nikon’s own 85mm f/1.8 which is only $500 and offers greater DoF control and light-gathering ability on it’s intended format. When you take into account that larger-format lenses also require more materials, you really must wonder why that 32mm is so expensive. So, I think it is important that consumers understand aperture equivalence at some level, if for no other reason than to be able to see through the marketing BS when manufacturers falsely claim a lens is equivalent to something it’s not. I suppose you could argue that in compact systems part of what you pay for is the size, but I think a lack of consumer knowledge of this topic has let camera companies to get away with charging exorbitant prices just because their lens is an f/1.4 or f/1.2. Another example: I would love to have a “nifty fifty” equivalent for my M4/3 system, but the cheapest one is the Olympus 25mm f/1.8 for $400. Canon’s 50mm f/1.8, as much as I would never want to shoot that lens, is only $125. Maybe what we need more of is price equivalence…

    Wow, my apologies, I did not intend for that comment to turn into such a long rant haha. Again, great read!

    1. Li

      Haha! “Price equivalence” is right on the issue!

      I understand that business is business though. Not like Panny are really making a killing in their camera business for example, they have the right to charge what they want for their lenses. So my hope is for Sigma to come in to the mft market in a big way to really shake things up, in speed and price.

  108. Jonathan

    Thanks for the article. I agree that there are pros and cons for each format but camera / lens size, weight and cost are an important factor.

    Currently for me the Pentax K-5 (APS-C) is a pretty good compromise in size / weight / cost / performance and capability. Great thing about Pentax is that they make relatively compact but rugged cameras that fit nicely and are very nice to use. I accept that the ideal balance is different from one photographer to another and I don’t like format snobbery.

    Even so I can see that some day I might be tempted to acquire a full frame (if Pentax ever put a compact FF DSLR out) as part of my photographic journey (and photography is a journey in my view). The viewfinder in my old Pentax ME (film) is just wonderful and its a relatively compact camera too.

  109. kalle-bah

    Just a thought on DoF
    Aps-c vs 4/3, same focal lenght, same aperture that is…

    Because of the difference in aspect ratio between the sensors (assuming the “crop factor” is based on the total size of the sensor) the difference in Dof will be larger or smaller depending on if the object you are trying to frame is composed with the height or the width of the frame in mind. However if the object is framed in height the aps-c user could always tilt the camera to “portrait orientation”, take a few steps closer and get even shallower DoF. All depending of how you wish the photo to look like of course.

    On the other hand…

    In many photo occations like wildlife, street, sport etc…we don´t get to choose the distance we take the photo from. All about “catching the moment”.
    For example…
    Two best friends are out in the wild to catch some action with their diffrent systems. One beeing aps-c and the other one 4/3. Both using their beloved 300mm f4,0 lenses at f4,0.
    They hear a suspicious sound coming from behind. Both turning around at the same time only to see a scared deer running of.
    Snap!, snap! A deers behind is better then no deer at all right?
    Now both guys will have the same deer in the same DoF, only the aps-c guy will have more scenery around the deer in his frame. The 3/4 guy will have more deer´s behind in his.
    Of course none of the guys is satisfyed and wants to crop their photos.
    Then of course pixel density, sharpness of the lens used and iso managment comes to play.
    In some situations the larger sensor user benefits from beeing able to choose a shallower DoF, in many others we take what we get.
    I use aps-c myself but are looking into getting 4/3 instead.

    Just some thoughts and sorry if the English is incorrect.

  110. Carlos

    … and what about the “aperture equivalence” using FF lenses on crop sensors?
    For example, using a FF 50mm F1.8 lens on a APS-C camera will have an equivalence of a 75mm F1.8 or F1.2 lens?

    Regards,
    Carlos.

    1. Dude

      Read the article again…

  111. Li

    Great article. I think I understand the facts you are presenting, but disagree on the conclusions.

    I agree with other commentators that the fact that the 12-35 f1.4 for mft does not exist, and the very sharp Sony 28-70 f4-5.6 ff kit lens goes for under $300 new, means aperture equivalence does matter. “Most advanced photographers understand the trade offs” – fair enough. But everyone else? I certainly did not a few days ago.. I mean I understood the difference in dof thing, but the total light on the frame issue ( tricked by iso) I had no idea.

    The more 18-35 f1.8s and similar come out, and I guess third party lens makers have the most incentive to shake things up a bit, the more I will agree “equivalence doesn’t matter”.

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