(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.
Blog | About | Flickr | Twitter | Facebook | Google+ | 500px.com | LinkedIn | Email
Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.