Canon 100-400mm F/4.5-5.6L IS USM Review

When I switched from film to digital in 2004, the Canon 100-400mm F/4.5-5.6L IS USM was one of the primary reasons why I decided to go with Canon instead of Nikon (the other related reason being the far greater availability of image stabilized lenses put out by Canon). In terms of flexibility, this lens is, I think, the best wildlife lens available today. The reasons are fourfold: it is light, it has excellent zoom range, it has image stabilization so you don’t always need a tripod, and it can focus close enough that you can use it on small subjects. The autofocus is also supposed to be significantly faster than competitors’ lenses (the Nikon 80-400mm F/4.5-5.6D ED VR and Sigma 80-400mm F/4.5-5.6 EX DG APO OS), although I’ve never tried these other lenses so I don’t know for sure.

Flexibility is indeed the Canon 100-400mm’s greatest strength. If you are looking for one wildlife lens to do it all, this lens is it. With digital crop from a Canon Digital Rebel or 30D you have a 160-640mm F/4.5-5.6 lens, which is absolutely tremendous. That is wide enough to get the entire body of large mammals and long enough to do bird photography. To get that in a hand-holdable lens for a bit over $1000 is pretty unbeatable. The Canon 100-400mm F/4.5-5.6L IS USM can also focus down to 1:5 magnification (with digital crop this becomes about 1:3), which is enough magnification to fill the frame with things like butterflies. Coupled with a Canon 500D closeup diopter lens, it can also become a supertelephoto image stabilized macro lens, which is a great setup for insect photography. The Canon 100-400mm only weighs about 3 pounds, and as long as I use a shutterspeed of 1/100 th of a second or faster, I can use it without a tripod. It’s therefore a phenomenally easy lens to walk around and to travel with, which you should not underestimate. I’ve used it a lot of times when I didn’t have the energy to carry around my Sigma 500mm F/4.5 lens, and if I had only had the 500mm I simply wouldn’t have gone out that day.

Flexibility does come with tradeoffs however, and there are certain weaknesses with the Canon 100-400mm lens. It loses some sharpness at the long end, and while that can be somewhat overcome by stopping down to F/8 or more, stopping down to F/8 means that you lose the ability to take images with the pop of having sharp subjects with completely blurred out backgrounds. In fact, even at F/5.6 at 400mm it’s hard to get the same pop in images that you can get with longer and faster lenses. Still, if Canon were to make the lens faster you would lose the ability to hand hold it without a tripod: Nikon has done that with the Nikon 200-400mm F/4 G-AFS ED-IF VR lens, and it weighs in at 7 pounds (more than twice as much as the Canon 100-400mm F/4.5-5.6L IS USM), meaning that it is essentially impossible to use without a tripod. The other weakness is the push-pull zoom design, which has a tendency to collect a lot of dust. If you’re mainly shooting in New England forests, dust isn’t too much of a hassle; if you go to Africa or India where everything becomes covered in a thin layer of sand, though, it does become more of an issue. Some people also don’t like the feel of the push-pull zoom, although that has never bothered me too much.

So who should get this lens, and who shouldn’t? If you shoot a lot of large mammals and/or large wading birds (egrets and the like), this is a great lens. You lose some sharpness compared similarly priced prime lenses such as the Canon 400mm F/5.6L USM or the Canon 300mm F/4.0L IS USM, but for me it’s worth the tradeoff in sharpness to gain the ability to zoom out and get completely different compositions. If you are mainly interested in birds, however, you are probably better off with a prime (fixed focal length) lens. Prime lenses are sharper and have faster autofocus, and for birds you will pretty much always be shooting at the 400mm end of the lens and not have much use for zooming out. If you already have a prime lens, the Canon 100-400mm lens might still be worth adding. I have a fast supertelephoto lens, the Sigma 500mm F/4.5, but I use the Canon 100-400mm for most of my mammal work, macro photography, and when I want to travel lightly. And in that role there is no better lens on the market.