- \n
- This is not intended to show or imply superiority of any format over another. \u00a0At all. \u00a0I 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).\u00a0<\/em>
\n<\/em><\/li>\n- 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. \u00a0This is not an argument about using ‘equivalence’ as a point of reference.<\/em><\/li>\n
- 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.<\/em><\/li>\n
- I have made some minor edits to the text in order to clarify some of the above.<\/em><\/li>\n<\/ul>\n
What does “Full Frame Equivalent” mean?<\/h3>\n
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:<\/p>\n
- \n
- Full Frame: <\/strong>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.<\/li>\n
- Crop Sensor:<\/strong> 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.<\/li>\n
- APS-C: <\/strong>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.<\/li>\n
- Four-Thirds or 4\/3:<\/strong> 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<\/li>\n
- Field of View or Angle of View: <\/strong>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\u00b0. This is the angle between the upper left of what’s captured by the lens and sensor and the bottom right (or vice versa).<\/li>\n<\/ul>\n
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.<\/p>\n
![\"A](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/Angle_of_view-300x237.jpg\")
<\/a>A diagram showing angle of view and the effect a crop sensor has on a lens’ angle of view<\/figcaption><\/figure>\n Crop Factor<\/h4>\n
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.<\/p>\n
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.<\/p>\n
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.<\/p>\n
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.<\/p>\n
![\"Digital](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/Sensor_sizes_overlaid_inside_-_updated.svg_.png\")
Digital Sensor Sizes and their “Crop Factors” – image by MarcusGR, Wikimedia Commons<\/figcaption><\/figure>\n 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.<\/p>\n
Aperture ‘equivalence’<\/h4>\n
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:<\/p>\n
A few things regarding aperture:<\/p>\n
- \n
- 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.<\/strong> 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.)<\/li>\n
- The f-stop is one of the key components in exposure. The intensity<\/strong> 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.<\/li>\n
- 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).<\/li>\n
- 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.<\/li>\n
- Background Blur: The amount that the area behind your subject is blurred. Using really wide-aperture\n
![\"A](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/chloe_iphone-300x245.jpg\")
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.<\/figcaption><\/figure>\n 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.<\/strong> 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.<\/li>\n<\/ul>\n
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.<\/p>\n
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).<\/p>\n
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. <\/strong>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.<\/p>\n
Total Light<\/h4>\n
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<\/strong> 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.<\/p>\n
![\"Noise](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/dxo_iso.jpg\")
Noise comparison – OM-D E-M5, Canon 5D and 5D Mark II, Courtesy, DxO, Click to Visit DxO Labs Comparison Tool<\/figcaption><\/figure>\n 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. \u00a0You may be thinking ‘that’s close enough, but it speaks to the further point:<\/p>\n
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).<\/p>\n
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\u00a0for 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.<\/p>\n
Now, let me tell you why none of this matters: Next Page<\/a><\/h3>\n
<\/p>\n
Why Full Frame Equivalency Doesn’t Matter<\/h3>\n
Now, after that longwinded explanation of all this equivalency stuff…does it matter? What effect does it have on your photography? In my opinion,if you’ve selected your camera format based on your preferences, full frame equivalency doesn’t matter one iota.<\/p>\n
Full Frame is not a Magical Reference Format<\/h4>\n
![\"The](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/h4d60_mini-300x217.jpg\")
The Hasselblad H4D-60, a Medium Format Digital Camera<\/figcaption><\/figure>\n The biggest issue I have with all the equivalency talk is that it treats the 35mm size as some sort of magical reference format where lenses act their ‘true’ self. This is flat out not the case, and it comes mainly from the introduction of the ‘crop factor’ to help out 35mm photographers who transitioned to digital when APS-C was pretty much all there was. Before 35mm became popular, most photographers shot with a larger format. 35mm was the ‘mini’ format of its day. Ansel Adams predominantly used 8×10 and 4×5 view cameras, with a film size many, many times that of 35mm. In fact, if people used ‘crop factors’ back in that day, they would consider 4×5 to be a 2x crop factor of 8×10 and 35mm to have a crop factor of 7.5x!<\/p>\n
While there certainly was some snobbery about the size of 35mm film vs a large format or medium format film, the size differences there are many times what we are talking about between full frame and smaller format interchangeable lens cameras of today. The ‘normal’ lens on 645 medium format camera is 75mm. On 35mm it’s 50mm, on APS-C it’s 30-35mm, and on 4\/3 it’s 25mm. Why don’t we make 645 medium format the ‘reference’. Then ‘full frame’ would have a crop factor too? The whole point is, the use of 35mm as the ‘master format’ is arbitrary, and the use of crop factors to denote equivalent lenses is a modern invention that has little use except to help jog the memories of those used to one format and transitioning to another.<\/p>\n
If you don’t have tons of experience and mental ‘feel’ for what a specific focal length or aperture acts like on 35mm, forget the crop factor ENTIRELY. It is of absolutely ZERO use to you.<\/strong> Why reference a format of camera that you aren’t using?<\/p>\n
Full Frame Advantages<\/h3>\n
Now, before I tell you why worrying about ‘equivalence’ is irrelevant, you need to first understand that I am not saying that full frame cameras don’t have some very real advantages over smaller format cameras. They do, but only ONE <\/strong>of them relates to aperture. Full frame cameras have the following advantages over smaller format DSLRs and Compact System Cameras (CSCs):<\/p>\n
- \n
- Lower Noise. Full frame cameras of similar sensor technology to their smaller counterparts will yield lower noise images at its baseline, and continuing throughout the range. Generally, it’s about half to one stop advantage over APS-C and about 1-2\/3 stop advantage over 4\/3.<\/li>\n
- Richer tonality. Full frame cameras generally have higher color bit depth and therefore a little richer tonality and colors. This can give them a somewhat intangible look that gives that little extra something to an image.<\/li>\n
- The ability for shallower depth of field and extremely blurred backgrounds. While you can certainly acheive plenty of background separation and shallow depth of field with APS-C and 4\/3 sized sensors, you aren’t going to match the ability of a full frame camera with a hyper fast lens like an 85mm f\/1.2 or a 300mm f\/2.8 to obliterate the background.<\/li>\n<\/ul>\n
And, that’s pretty much it. It used to be that you could add Dynamic Range (the ability to capture a wider range of shadows and highlights in a single image) to the list above, but in recent times, this isn’t the case. While a full frame sensor of the same sensor technology will still generally have a little better dynamic range, this has much more to do with the individual sensor than the size any more. For instance, the Olympus OM-D E-M5 has better dynamic range than ANY Canon DSLR ever made, while the APS-C Nikon D5200 is within 1\/3 stop of matching the dynamic range of the Nikon D600.<\/p>\n
The Fallacy of Aperture Equivalence<\/h3>\n
While crop factor has a use simply to compare focal lengths between formats and such, the constant comparison of a smaller format lens to its full frame ‘equivalent’ aperture is largely unevenly applied and misunderstood. It’s often used to show that a smaller format is inferior or not capable of the same things as a larger format. In some cases, this usage is correct, but it is also nearly never used the other way.<\/p>\n
I’ve heard many times “Yeah, your 75mm f\/1.8 is crap – it’s like a 150mm f\/3.6.” No, it’s not, it’s a 75mm lens with an f\/1.8 aperture and a field of view that is the same as a 150mm lens on full frame.<\/p>\n
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 Sony Zeiss 135mm f\/1.8 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. If I’ve chosen a smaller format system, I’m already OK with the fact that it doesn’t equal a full frame camera in the noise department, so there is no ‘aperture advantage’ after the fact. Those who harp on aperture equivalence as it relates to shallow depth of field also IGNORE all the BENEFITS to having more depth of field for the same aperture:<\/p>\n
- \n
- Times you WANT a little more depth of field than your lens can provide wide open. (portraits where you want more than one eyelash in focus; indoor travel photos like shooting inside a cathedral, etc). Often these situations are situations where a tripod is not allowed or not practical.<\/li>\n
- 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.<\/li>\n
- Landscape photography when it’s windy, or you’re trying to stop motion – being able to shoot at f\/8 rather than f\/16 can be quite helpful.<\/li>\n
- Macro photography, where inherently deeper depth of field is most desirable, especially when lighting is problematic.<\/li>\n<\/ul>\n
These situations make up a LOT of shooting. Now, when light is limited in any way, these advantages come up. Now, sure, you can up the ISO two stops on the full frame camera to compensate (or 1-1\/3 stops when comparing to APS-C), but now, the full frame camera has just lost ALL of its image quality advantages, and you’re still stuck carrying the larger and more expensive gear.<\/p>\n
When do you need to stop down indoors? Group shots, any time you want to get two people at different depths in the image in focus, indoor architecture shooting when traveling (most European cathedrals won’t let you use a tripod), etc.<\/p>\n
Most advanced photographers using a smaller format understand the tradeoffs<\/span><\/p>\n
Here’s the big one. If you have chosen a smaller sensor camera, and are an advanced enough photographer to have mastered the relationship between aperture and focal length and such, and own several lenses and such, then you’ve made that choice understanding the tradeoffs, and ‘equivalence’ talk is useless. It’d be the same if every full frame photographer heard that their 24mm f\/1.4 was really ‘only’ equivalent to a 180mm f\/11 on an 8×10 view camera. Yes, that would be the ‘equivalent’ lens in focal length and aperture for the same depth of field, but who cares? It’s irrelevant to the discussion on the camera the person is actually using. Just like a 35mm format photographer has made the tradeoffs from large or medium format for a more responsive, smaller kit, so too have APS-C and 4\/3 format photographers made the choice to forgo a little noise performance and some ability to shoot at ultra shallow depth of field in exchange for smaller size or more affordability.<\/p>\n
Given that my lenses give me shallow enough depth of field for most anything I could ever want, and image quality is absolutely good enough for most any size print I make, I simply get to save 12 lbs of gear in my bag for the same apertures and field of view. I shot with APS-C DSLRs for four years before moving to full frame in 2009. I shot with a full frame Canon kit with a bag full of L lenses, so I know what a top flight full frame kit can do. I’ve made my decision that portability and light weight are more important to me as a photographer than the ability to do sliver thin depth of field. In fact, I think my photos from the past two years are far BETTER than those I got with my full frame kit, simply because I enjoy shooting more and I take a lot more photos as a result.<\/p>\n
So, those of you who keep hammering on this ‘equivalence talk’, please stop. We’ve already made the decision to forgo extremely shallow depth of field by our choice of cameras. The aperture equivalence talk when harping on crop lenses\u00a0is only relevant if you are somehow trying to gain back full frame levels of shallow depth of field, or you are somehow trying to get another system to exactly match the output of a full frame system, which is a fools errand. The formats are not equivalent. Why should discussions of lenses be framed in a way that assumes they should be?<\/p>\n","protected":false},"excerpt":{"rendered":"
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’. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"cybocfi_hide_featured_image":"","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"enabled":false},"version":2},"_links_to":"","_links_to_target":""},"categories":[21,22],"tags":[],"class_list":["post-1541","post","type-post","status-publish","format-standard","hentry","category-opinion","category-shop"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p28RGq-oR","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/posts\/1541","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/comments?post=1541"}],"version-history":[{"count":31,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/posts\/1541\/revisions"}],"predecessor-version":[{"id":1569,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/posts\/1541\/revisions\/1569"}],"wp:attachment":[{"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/media?parent=1541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/categories?post=1541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/admiringlight.com\/blog\/wp-json\/wp\/v2\/tags?post=1541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- The f-stop is one of the key components in exposure. The intensity<\/strong> 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.<\/li>\n
- Crop Sensor:<\/strong> 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.<\/li>\n
- 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. \u00a0This is not an argument about using ‘equivalence’ as a point of reference.<\/em><\/li>\n
![\"A](\"http:\/\/admiringlight.com\/blog\/wp-content\/uploads\/2013\/01\/Angle_of_view.jpg\")
<\/a>