{"id":11067,"date":"2022-03-03T13:30:00","date_gmt":"2022-03-03T18:30:00","guid":{"rendered":"https:\/\/admiringlight.com\/blog\/?p=11067"},"modified":"2022-03-03T13:49:30","modified_gmt":"2022-03-03T18:49:30","slug":"review-canon-rf-100-400mm-f-5-6-8-is-usm","status":"publish","type":"post","link":"https:\/\/admiringlight.com\/blog\/review-canon-rf-100-400mm-f-5-6-8-is-usm\/","title":{"rendered":"Review: Canon RF 100-400mm f\/5.6-8 IS USM"},"content":{"rendered":"\n

Canon has been busy churning out lenses for their full-frame RF mount, and this past fall released two interesting consumer-grade lenses. The first is the tiny ultra-wide 16mm f\/2.8, which I reviewed recently<\/a> and really enjoy. The second is the subject of today’s review, the Canon RF 100-400mm f\/5.6-8 IS USM. When this lens was first announced, I may have rolled my eyes. Sure, it’s a great focal range of 100-400mm, but the lens is also a full stop slower than the typical 100-400mm zoom lens, with a maximum aperture of f\/8 at the long end of the zoom range. But then I started seeing some samples and very positive first hand reports and I had to try it out. What I’ve found has surprised me. Read on to find out why. <\/p>\n\n\n\n

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The Canon RF 100-400mm f\/5.6-8 on the Canon EOS R5<\/figcaption><\/figure>\n\n\n\n

Construction and Handling<\/h3>\n\n\n\n

The first area where I was pleasantly surprised is in the construction of the lens. The RF 100-400mm is part of Canon’s consumer-grade line of lenses, but I was shocked to see how nicely built this lens is. The 100-400mm has the now standard RF matte black polycarbonate exterior and metal lens mount, but the tolerances of construction on the lens are very high. There are no creaks and everything is tightly assembled. <\/p>\n\n\n\n

The large zoom ring sits closest to the lens mount and features silky smooth zoom action. Indeed, the zoom feel on the 100-400mm is superior to that of both my RF 24-105mm f\/4L and RF 70-200mm f\/2.8L. The lens extends substantially when zooming to the long end of the zoom range, but the extending lens tube has no play in it at all. <\/p>\n\n\n\n

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The RF 100-400mm f\/5.6-8 at 100mm (left) and 400mm (right)<\/figcaption><\/figure><\/div>\n\n\n\n

The broad manual focus ring has a similarly nice feel, with extremely smooth rotation and excellent damping. The standard RF control ring at the end of the lens turns with a nice resistance with subtle but distinct clicks as you turn. The overall package is impressively taut for a lens that is very budget oriented given the focal range. I would assume that the internal construction of the lens is not quite as robust as the L-series lenses, and the RF 100-400mm lacks any weather sealing for inclement weather, but it is a well constructed lens. <\/p>\n\n\n\n

After using this lens for a while, it has been an absolute joy to have a full-frame long range telephoto zoom lens that is this lightweight and compact. Canon has been doing this with a lot of RF lenses, including both 70-200mm zoom lenses, which are impressively small for what they are. The RF 100-400mm f\/5.6-8 continues that trend with a lens that can easily fit in a typical shoulder bag, and even fits with the camera mounted in most bags. <\/p>\n\n\n\n

When you look at it compared to lenses of similar reach, and then then compare to other small telephoto zooms, it puts the small size of the 100-400mm into perspective:<\/p>\n\n\n\n

Lens<\/strong><\/td>Weight<\/strong><\/td>Length<\/strong><\/td>Diameter<\/strong><\/td><\/tr>
Canon RF 100-400mm f\/5.6-8<\/td>635g<\/td>164.7mm<\/td>79.5mm<\/td><\/tr>
Canon EF 100-400mm f\/4.5-5.6L II<\/td>1640g<\/td>193mm<\/td>94mm<\/td><\/tr>
Sigma 100-400mm f\/5-6.3 DN (Sony E)<\/td>1135g<\/td>197.2mm<\/td>86mm<\/td><\/tr>
Canon RF 100-500mm f\/5-7.1L<\/td>1365g<\/td>207.6mm<\/td>93.8mm<\/td><\/tr>
Canon EF 70-200mm f\/4L IS II<\/td>780g<\/td>176mm<\/td>80mm<\/td><\/tr><\/tbody><\/table>
Size and weight of selected telephoto zoom lenses<\/figcaption><\/figure>\n\n\n\n

Looking at the table above, it’s really astounding how compact this lens is. Yes, you pay for that compactness with a slower aperture, but the size benefits for that tradeoff are substantial. The 100-400mm f\/5.6-8 is over an inch shorter than all the other lenses that go to at least 400mm. The lens is nearly 1\/3 the weight of the EF 100-400mm, less than half the weight of the RF 100-500mm, and even nearly half the weight of Sigma’s mirrorless 100-400mm lens for Sony: a lens that many already considered extremely compact for a 100-400mm zoom. In fact, the lens is even smaller and lighter than Canon’s lightweight 70-200mm f\/4L II for EF mount. <\/p>\n\n\n\n

This sort of portability makes handling the 100-400mm a dream. It is a lens that can be carried for long hikes or even in the hand for long periods of time without any fatigue, and is easily thrown in the bag for some convenient reach. Ultimately, this is the sort of compact zoom that has been unheard of on full-frame cameras outside of mirror lenses. To go this compact in a lens with this much reach has previously required moving to smaller formats like APS-C and Micro 4\/3. <\/p>\n\n\n\n

One negative is Canon’s continued failure to provide lens hoods for non-L lenses. Canon continues to deny people hoods in the box and then charges outrageous prices to get them as an added accessory. The RF 100-400mm uses the ET-74B lens hood, for which Canon charges $45. I chose to go the route of third party here, and picked up Vello’s ET-74B clone, which can be had at B&H Photo for $15. Vello’s hood works well, and locks in place securely in both the in-use and stored positions, though a small plastic pin on the inside does very slightly brush the end of the lens barrel when reversing the hood for storage. I filed this little pin down to avoid the minor scraping.<\/p>\n\n\n\n

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The Canon RF 100-400mm f\/5.6-8 with Vello hood<\/figcaption><\/figure><\/div>\n\n\n\n

Autofocus and Image Stabilization<\/h3>\n\n\n\n

Most of Canon’s consumer-grade RF lenses come with their STM stepping motor for autofocus, but the RF 100-400mm is one of two that feature their latest Nano-USM focus motor (the other being the RF 24-240mm). That USM motor pays off big time, as the 100-400mm focuses extremely quickly and accurately. When mounted on my R5 in good light, the 100-400mm focuses nearly instantly. When shooting flying birds, the animal eye-detection works wonderfully in conjunction with the lens, with a very high rate of accuracy. As light levels drop, the dimmer maximum aperture causes the autofocus to slow down a bit. This will limit the lens’ use for sports in low light, but in sunny or bright conditions, it can track action very well. <\/p>\n\n\n\n

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Seagull flying – Canon EOS R5 with Canon RF 100-400mm f\/5.6-8 IS USM @ 400mm, f\/8, 1\/1250s, ISO 800<\/figcaption><\/figure>\n\n\n\n

The lens also comes with an optical Image Stabilizer, which can work in conjunction with the IBIS on the R5 and R6. When used on the R5, I found the stabilizer to allow for hand-holding at shutter speeds as low as 1\/15 second at 400mm with good technique, which is around 5 stops slower than I can hand-hold without the stabilizer on. When shooting on my EOS RP, which lacks in-body stabilization, I still was able to get sharp shots around 1\/20-1\/25s, yielding around 4.5 stops of stabilization in real-world use. This is an excellent performance, and a great thing to have in a long telephoto zoom lens. <\/p>\n\n\n\n

Continue: Image Quality<\/a><\/h4>\n\n\n\n\n\n\n\n

Image Quality<\/h3>\n\n\n\n

As we get to image quality, let’s remind ourselves that this is a consumer-grade 400mm telephoto zoom that costs $650. And that brings us to the next surprise: This lens is pretty darn good optically. <\/p>\n\n\n\n

Sharpness<\/h4>\n\n\n\n

The biggest knock on the RF 100-400mm is it’s fairly slow maximum aperture, which starts at f\/5.6 at 100mm, starts to close down to f\/6.3 by 120mm, f\/7.1 by around 160mm, and f\/8 from 260mm and longer. With these slower apertures, it is critical that the lens perform well at or very close to the maximum aperture, and I’m glad to report that it does. The RF 100-400mm shows very good to excellent sharpness across the majority of the frame at all focal lengths, right from the maximum aperture. There is some minor softening at the edges and corners, but even these maintain very good levels of resolution when shooting more distant subjects. The lens is softest at 400mm, but even at 400mm and f\/8, sharpness is on good to very good levels. Stopping down generally doesn’t do a whole lot to affect sharpness, save for the softening effects of diffraction at very small apertures. Click here <\/a>for a 100% crop of the top edge of the shot below, taken at 400mm and f\/8. <\/p>\n\n\n\n

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Leveque Tower – Canon EOS R5 with Canon RF 100-400mm f\/5.6-8 IS USM @ 400mm, f\/8, 1\/125s, ISO 100<\/figcaption><\/figure><\/div>\n\n\n\n

The lens can focus as close as 88cm, which produces a very useful 0.41x maximum magnification. This isn’t into true macro territory, but will provide plenty of magnification for larger insects like butterflies or other small objects. Sharpness near minimum focus distance is still good in the central part of the frame, though not quite as sharp as it is when focused further away. Also, the edges perform worse at these closer distances, and as such the edges and corners are soft when shooting very close subjects. Still, a decent performance here. If shooting closer up at 400mm, stopping down to f\/11 can give you a small boost in resolution and contrast.<\/p>\n\n\n\n

I do want to mention one thing as an advisory item. Like a lot of long lenses, the RF 100-400mm can be quite sensitive to filters, especially when shooting near 400mm. I was using a mid-range Hoya HMC polarizer that I’ve owned for years and used hundreds of times without issue, and I noticed that the lens was completely incapable of producing a sharp image at the long end. I thought something was wrong with the lens. Then I took the filter off and was greeted with beautifully sharp images. Putting on a different polarizer yielded some very minor softening, but was a significant improvement. So word to the wise: make sure you’re using high quality filters if you choose to use one with this lens. <\/p>\n\n\n\n

Bokeh<\/h4>\n\n\n\n

While the 100-400mm f\/5.6-8 is not exactly a fast lens, the long focal length means that it is capable of isolating subjects and blurring the background. Here too, the 100-400mm puts in a surprising performance. In most situations, I found the bokeh from the lens to be very pleasing, with soft falloff and a general lack of nervousness. There can be the slightest inner ring at the edge of specular highlights, but that’s about all I have to complain about. It’s not the creamiest bokeh of any lens, but consumer telezooms often perform quite poorly with regards to bokeh, so it’s very nice to see some attention paid to this part of the rendering. <\/p>\n\n\n\n

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Backlit Plant – Canon EOS R5 with Canon RF 100-400mm f\/5.6-8 IS USM @ 400mm, f\/8, 1\/500s, ISO 800<\/figcaption><\/figure><\/div>\n\n\n\n

Color, Contrast and Chromatic Aberration<\/h4>\n\n\n\n

The RF 100-400mm provides images with good color and contrast, but nothing out of the ordinary for modern Canon glass. Stopping down does little to contrast throughout the range, and it doesn’t really need to. <\/p>\n\n\n\n

The lens produces a moderate to high amount of lateral chromatic aberration throughout the focal range. Below is an example of the lateral CA that is present at the edges of the frame at 400mm. As with most lateral CA, modern RAW converters can easily correct for this. A crop of the corrected frame is shown on the right. <\/p>\n\n\n\n

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Lateral CA at 400mm. Uncorrected (left) and corrected (right)<\/figcaption><\/figure>\n\n\n\n

The 100-400mm shows a little longitudinal CA, with a green tinge on background objects and a purple tinge in the foreground, but it’s fairly well controlled. I found nothing really to worry about in that area. <\/p>\n\n\n\n

Distortion, Flare and Vignetting<\/h4>\n\n\n\n

The RF 100-400mm f\/5.6-8 shows a moderate amount of pincushion distortion that is present throughout the entire focal range. JPEG shooters or those using RAW converters with lens profiles won’t ever have to worry about it. The lens profiles in Adobe Lightroom and DxO PhotoLab correct this perfectly. As has been par for the course as of late, Capture One does not have a profile for the lens yet, and based on their track record on Canon RF lenses over the past year or two, I wouldn’t expect one until at least 2024. <\/p>\n\n\n\n

The 100-400mm performs rather well against bright light, and flare is not much of a concern. There is a mild loss of contrast when the sun is near the edge of the frame, but even with the sun in frame, there is minimal ghosting and contrast loss. Very well done here. <\/p>\n\n\n\n

The lens shows some vignetting throughout the focal range, which is worst at 400mm, but nothing too objectionable. RAW lens profiles or JPEG images can take care of it if you feel the need. <\/p>\n\n\n\n

Overall, I was quite impressed with the optical quality of the 100-400mm lens. It’s not going to go toe-to-toe with Canon’s top-flight L zoom lenses, but it really only a small step down from those lenses. Good sharpness, decent bokeh, good flare control and only generally mild aberrations make this a lens that really performs well in its price class. <\/p>\n\n\n\n

Continue: Conclusion and Image Samples<\/a><\/h4>\n\n\n\n\n\n\n\n

Conclusion<\/h3>\n\n\n\n

Pros<\/h4>\n\n\n\n