Canon EF 100-400mm f/4.5-5.6L IS USM

alibaba: This is a big, heavy lens with an old school pull-push zoom mechanism. I rented this for a day at the beach taking pictures of surfers, and found that it's not the sharpest lens but with any lens with this range of zoom you don't expect the best quality. If you rent this lens, you should definitely stay away from 400mm range as you loose quality noticeably, 300mm would be your best bet. Using the pull-push zoom was interesting and easy. the friction ring is very helpful. the IS works great. This is a heavy lens so make sure you at least rent a monopod or tell your arms goodbye as they'll be toasted if you use it handheld.

Eliya: In spite of IS, this lens does not perform well without a tripod or monopod. I was hoping this would be a perfect hand-held lens for photographing wildlife on nature hikes, but I've been consistently disappointed with the quality of my photos. At f/5.6, you need a pretty high ISO to get the shutter speed down to something you can shoot hand-held, and even then, this isn't the sharpest of Canon's L lenses. Consider the faster and lighter 300 f/4 as an alternative. A 1.4x extender will make the 300 into a 420 f/5.6, and this combination will still autofocus (albeit slowly) on a crop sensor camera like the 7D. The 100-400 loses autofocus capability with an extender. If you're shooting on a tripod or monopod, this lens should be fine, and the zoom ability can be useful, but one of the heavier prime lenses might be a better bet.

Jason: Excellent lens, great build. It may have just been my choice of backgrounds as I was shooting, but I found the bokeh on this was not as smooth as some of the other Canon glass I've used. Shot the NCAA Div I Football Finals game with this in January (handheld!), as well as using it on a road trip. Great clarity, fast enough for full daylight levels, but found it a touch too slow for a night football game, even with the large amount of lighting. The push-pull zoom takes a little getting used to, but once you figure it out, it is very convenient. I loved the ability to lock it at a certain focal length. I would not recommending going handheld for long periods of time unless you can't take a mono/tripod with you (many stadiums don't allow them).

Charles: Amazing lens for soccer photography. The lens might seem a bit 'slow' at f4.5-5.6, but at least under the lighting conditions I was shooting under (evening, sunny summer day), it was more than fast enough The push-pull zoom takes a bit of getting used to I also found the lens very contrasty, which is a good thing.

Megamoneybags: I absolutely LOVE this lens! I brought it with me on a 6-day vacation to Tennessee and it was basically the only lens I used! I assumed the push-pull system would be unusual to handle, but, it is just like any other telephoto lens, except, you can lock the lens at a certain focal length. It is a little heavy though, but not heavy enough to where you need to use a monopod (trust me, I spent a whole day hiking while holding this lens, it's not that heavy!) Many reviews have stated that the lens is "soft" at 400mm, I strongly disagree with that. My results at 400mm where just as sharp at 100mm. I even printed a few photos that were taken at the 400mm focal length, there are no signs of "softness"! I plan to purchase this lens soon!