I use primarily for wildlife photography, I love it's speed and zoom. The push-pull is a little different to get used to but easy to get the hang of. The 1.4x III extender works amazing with this lens, however the 2x II extender does not work in auto focus. But I rarely pair them together any way.
400 mm really gets you close to the action. I have used this lens from the deserts of Arizona to the islands of Alaska and it has never disappointed me! It's an incredible lens!!
November 20, 2011
Great Lens, Know the Limits
I purchased this lens as I needed to give myself a bit more reach than my 70-200 could offer, even with the 1.4 extender. The versatility with the lens is great. The 100-400 range is perfect for photographing airplanes, wildlife, sports, etc. The images are sharp up until about 300mm and then there is a slight drop off in sharpness as you go beyond 300. The focusing at times can be a bit slow, which can be tough if you are trying to lock in on a moving subject. Finally the lens does seem to vignette a lot when mounted to a full frame, which is to be somewhat expected but maybe not so much to the degree I get at times. The lens is push/pull which is a bit uncommon now. However, the adjustment period really isn't bad and after a day of playing around it feels normal. The tension ring is great for allowing you to determine how much or how little force will be required to zoom in or out.
I have had this lens for nearly 5 months now and it does seem to be what I utilize the most. I still use my 70-200 f4L IS at times when I know I will not need that extra reach. My 70-200 copy is amazingly sharp and I find it to be a bit faster at focusing.
Overall, I do recommend this lens to almost everyone. It is a great versatile lens but does have a few limitations. It will be interesting to see if Canon does come up with something to replace it in the coming years as the current version is coming up on 16 years already. My version was a 2013 build, based on both the serial number and having come with the new center pinch lens cap. The design might be old, but Canon is still actively making them!
April 9, 2014
My favorite lens of all
I carry two 5dMkIII camera bodies on my Cotton carrier and this lens is always chest mounted. I love this lens. It's a great portrait lens and at 400 mm will take portraits from across the square. I wish it was faster than f/4.0 but if it was bigger it would be a pain to tote around and hold. It's fast focusing, doesn't hunt much, and gives very sharp images at wide open. Just remember to use 1/400 sec or faster (I use 1/500 or 1/640) to avoid blur. I almost never use tripod. I even got great shots of Musk ox from a rubber zodiak in Greenland. Has two focal distance settings--remember to use the right one to avoid hunting.
January 10, 2014
Back to the 100-400L
Purchased with a 1.4 teleconverter and have just started looking at the lens sharpness.
I have started using this lens with a full frame 6d and the images are very sharp and the focus is very accurate. The 1.4xIII converter does not appear to detract measurably from the sharpness of the lens at 400mm, very impressive so far.
The lens feel and tightness of the zoom mechanism is much improved.
August 1, 2013