Thoughts About the Canon EF 100-400mm f/4.5-5.6L IS Lens

Posted on 30 August 2012

(This is another post based on something I wrote elsewhere as a response to a question about this lens – I’m re-sharing it here with minor editing.)

I’ve used the Canon 100-400mm f/4.5-5.6L IS lens  a lot – for things as varied as handheld shooting of bicycle races and tripod-based landscape photography. Over time I’ve developed a few thoughts about the performance of this lens and some of the comments that I frequently hear and read about it.

First, especially from my tripod-based work, I have found that the lens is capable of very good performance in terms of image quality – e.g. “resolution.” This is true at all focal lengths, but more so perhaps at some than at others. To give one example, I also own the f/4 IS 70-200mm lens. At one point I tended to always switch to the shorter lens when shooting in the range up to 200mm, concerned about a potential sharpness hit with the 100-400. Over time I figured out that while the 70-200 is probably a very tiny bit sharper here, in most cases the difference in many kinds of shooting is insignificant and invisible in real-world output – and in many cases where I would have switched lenses I now leave the 100-400 on the camera.

The performance at the long end is also an interesting topic about which experience has taught me a bit more. We often hear that the lens is “soft at 400mm.” However, when I shoot the lens in good conditions and am careful about what I do, it performs very well at 400mm. (I think that a very, very careful inspection at 400mm might reveal that 400mm is not the focal length at which its performance reaches its optimum level, but that is most certainly not to say that it is”soft” at 400mm or otherwise poor.)

So, what could explain the reports of poor or soft performance at 400mm? I suppose it is possible that I have a miraculous copy of the lens that doesn’t exhibit a problem that really does afflict lots of other users, but I’m convinced there are other explanations in at least quite a few cases. From using long focal lengths for critical work – again, I do a lot of landscape shooting – I have learned that there are a number of issues that become more acute when shooting at 400mm and which make it much harder to get a “sharp” image than might be the case with other lenses. Some are obvious, some les so:

  • People often shoot these long lenses handheld and neglect to fully apply what they know about shutter speed and camera shake. Although the “rule” is subject to a lot of variation, using the 1/focal length “rule” as a frame of reference, if you would shoot 50mm at a minimum of 1/50 second, you would shoot 400mm at 1/400 second. However, most often you would probably not shoot your 50mm focal length at 1/50 second unless you had no other choice – you would more likely use a higher shutter speed of perhaps 1/100 or 1/200 or even higher, further reducing the risk of blur. To translate that to the 400mm focal length you would shoot at 1/800 or 1/1600 second – and I think that it is quite rare for most folks to regularly do this. (This is one reason that I’m willing to sacrifice a bit of noise and shoot at ISO 400 or 800 regularly when using this long lens to shoot, for example, athletics or birds in flight.
  • Many people overlook the effect of shooting through the atmosphere with long lenses, and they shoot at 400mm and blame the lens for being soft when the “softness” is actually the result of atmospheric instability. I recall seeing this very clearly for the first time when I shot some long distance photographs of the Golden Gate bridge with this lens a few years ago, manually focusing in live view, and found that I could get very sharp pictures of… the very distorted and “wavy” effect of “heat waves” distorting the cables of the bridge. This effect is negligible when shooting nearby subjects, but when using the long focal lengths to shoot distant subjects it can be so significant that it renders some shots unusable.
  • In the same way, atmospheric haze is magnified when the long lens compresses distance. The subject appears closer, but you might be shooting through many times the amount of atmosphere and many times as much haze. This reduces dynamic range and contrast and creates an effect that many might read as “softness,” especially when combined with the “heat wave” effect and even more so when obsessively pixel-peeping at 100% magnification.
  • There are some important skill issues when shooting with such long focal lengths, as well, especially when it comes to some of the subjects that people often use them for. Two of the most common subjects are wildlife (especially birds and birds in flight) and sports. In both cases, the issues of the long lens compound the problems of handling a camera that is in motion to track such subjects. It took me a lot of practice to get to the point that I can, with reasonable accuracy and expectation of success, track, frame, and focus on fast-moving subjects like birds in flight or bicycle racers with such long lenses and not end up with all sorts of problems. This is not a lens issue – it is a human issue and the solution is more about practice than about getting a better lens.


If this article helped you make a purchase decision, please considering purchasing your Canon 100-400mm f/4.5-5.6L IS lens from B&H Photo though this link and helping support this blog. Thanks!

© Copyright 2012 G Dan Mitchell – all rights reserved.

G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
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11 comments to Thoughts About the Canon EF 100-400mm f/4.5-5.6L IS Lens

  • AlanNo Gravatar says:

    Right on. Accords with my experience.

  • QT LuongNo Gravatar says:

    The copy of the 70-200/2.8 IS (not II) that I have (and which I did not handpick) is no better than my 100-400.

    • Seems like a lot of people who have actually used the lens have found it to be a fine performer. I had the same experience as QT, though in my case the comparison was to both the IS and non-IS versions of the 70-200mm f/4 lens. In a lot of cases, if I carry the 100-400mm lens, I may leave the 70-200mm at home. The 70-200mm has advantages of size and weight in some cases where I don’t think I’ll need the longer reach, and it is also a very fine lens.


      • RonNo Gravatar says:

        I wanted to thank you for this info in the article (Thoughts about the Canon EF 100-400mm f/4.5-5.6L IS Lens)
        I shoot the 100-400 lens with a tripod only and was having problems with the long side (soft). I could not figure out what was wrong. I asked other 100-400 shooters about this and no one could tell me what was wrong. They had the same problem. I even sent my 60D and lens back to Canon for calibration. They could not explain what was going on. Your article makes a lot of sense. I never thought of the atmosphere as a problem. In shooting long range rifles one has to figure in the atmosphere. It only makes sense when it comes to the lens. I am going to adjust for this and see how things improve. I will let you know. Again thank you. I hope you saved the rest of the hair on my head.

        • Ron:

          Thanks for writing, and I’m glad to hear that you found the article useful. Realizing that there are additional challenges to getting a sharp image with a long lens is very important, and a lot of people overlook things like the effect of atmospheric distortion, the effect of compressing atmospheric haze and humidity, and the more obvious factors such as camera stability.


  • Dan:

    Interesting comments on the 100-400, and all helpful and valid observations.

    I did a direct comparison a while back of the 100-400 vs. 300mm f/2.8 vs. 135f/2 on both a Canon 40D and 5D bodies – just out of curiosity. Of course, they all perform well, and resolution is pretty terrific no matter which lens is used. I’ll see if I still have all of the comparison shots somewhere. Not surprisingly, the 300f/2.8 is the sharpest at 300mm, and it has great edge/corner sharpness that surpasses the 100-400. It is also sharper in the center, and at wider apertures. The 100-400 is best around f/11 – f/14 from my experience, and softer (of course) wide-open.

    On the other hand, it is hugely convenient to have a zoom, and the 100-400 is a lot lighter and smaller than the 300 f/2.8, and with the 100-400, I may get shots I’d miss with the 300, just because I’d otherwise be fiddling with teleconverters or camera bodies. The 100-400 also has great contrast vs. the consumer line of lenses, and that is very noticeable.

    Again however, the 100-400 has been a terrific lens for me and its versatility has helped in a lot of situations (and it is still “hikeable”!).

    A few comments on the 300 f/2.8 – I’ve found that the combination of that lens with the 1.4x and 2x and even stacked 1.4x + 2x (Canon … with the accepted loss of effective aperture f2.8 becoming f/8) teleconverters produces remarkable results. On the 5D (full frame sensor) – this gives 300mm, 420, 600, and 840mm (won’t autofocus) as possible focal lengths, on the 1DMarkIV which WILL autofocus at f/8, this gives effective focal lengths of 390mm (f2.8), 546mm (f4), 780mm (f5.6), and 1092mm (f8), and if you’re really nuts, you can mount all of this on a 7D for 480, 672, 960, and 1344mm effective focal lengths. This actually makes for a pretty versatile long end telephoto.

  • [...] G. Dan Mitchell: Thoughts About the Canon EF 100-400mm f/4.5-5.6L IS Lens: [...]

  • JohnNo Gravatar says:

    Hi Dan,

    I bought the 100-400 in early 2012. Prior to that, for many years, I used my 70-200 f/2.8L IS, or 300 f/4L (non IS, sometimes with a 1.4x). I found I would leave one or the other behind when out walking to keep the weight down. When I found wildlife, I never seemed to have the ideal focal length mounted on the camera. Finally, I became convinced that the convenience and features of the 100-400 would outweigh any IQ advantages (particularly if I’d left the other lens at home, or didn’t have time to switch out a lens).

    When I got the 100-400, I tested the lens to make sure everything worked. The optics seem to be on par with my 70-200, which is excellent in my opinion. On my 50D however, I needed -5 MFA, which is the most I’ve ever needed with any Canon lens.

    The 100-400 has several significant (mostly obvious) advantages for my use over my 300 f/4L. But one I feel many overlook is the minimum focus distance. My older non-IS 300 focuses down to 2.5m, while the zoom goes down to 1.8m. For me, this is a huge advantage when I’m able to get that close to a subject.

    I had a learning curve however.

    The 300, for me, was a tripod-only (or beanbag) lens. I just can’t hold it steady, even with a monopod. My kids are at an age where I don’t have time to setup a tripod on a walk, they’ll get bored and either hang on me or the tripod, or run off. So I tried IS, but I didn’t get nice images at first. This confused me because I have gotten very sharp images on the 70-200 down to 1/15th. I found two things… one, I needed to give the lens a moment to stabilize, and two, I did some reading and finally decided that I needed a much faster shutter. I setup a shutter priority based custom mode. Servo AF, Shutter priority set to at least 1/1000, etc. It seems to work quite well.

    I bought a 5D mark III after, and the improved AF and ISO handling over the 50D is a godsend for that custom mode. It is much faster to focus, and considerably more accurate. I thought I’d miss the extra reach, but that has not been the case for the most part. The 5D3 and 100-400 is a great, portable, flexible combo. BTW, I sold half of my gear to pay for the 5D3, including the 70-200 and 300.

    One other note on the 100-400. It seems like the build is more prone to vibration. I noticed image degradation even at fairly fast shutter speeds (1/250) on a tripod. With live view, I saw no problem. I compared at 300mm vs the prime and found the prime doesn’t transmit as much vibration as the zoom. So that is another reason I keep my shutter speed up now (or lock the mirror for slower tripod work). I’ve mentioned this to others and been told I’m nuts.

  • StephenNo Gravatar says:

    I had a 100-400 for about 5 years, used mostly for wildlife and birds in flight. Found it quite good for general wild life but had lots of trouble with BIF. Sold it and purchased the 400 f5.6 L. Now have a lot more keepers, main difference being the faster focusing and to a lesser extent a slight gain in sharpness. (Only lost about $100 on the lens, L lens certainly retain their value)

    • I think that if you need a lens that shoots only at 400mm and you aren’t interested in IS, the 400mm prime seems like a fine choice. As in all things, lens choices are often compromises, and we tend to try to find the best compromise for our own needs.

      400mm prime – Somewhat better performance at 400mm in terms of AF and maximum resolution. No IS. Loss of focal length flexibility.

      100-400 zoom – Somewhat weaker (though still good) performance at 400mm in terms of absolute sharpness and AF speed. Has IS. Focal length flexibility allows adaptability and perhaps avoids some lens changes.


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