Conclusion: I enjoy using this lens for outdoor portrait photography, some wildlife and selective landscape photography. I've had many good indoor shots as well. The autofocus is fast and silent, the image sharpness is INCREDIBLE. The most surprising feature is how lightweight this lens is, despite feeling well built. At half the weight of the f/2.8 version, this one is easily handheld. Use a 1.4x or 2x extender for longer range. I also like the included lens hood.
Excerpt: I can hardly find a real "con" out of this lens. Maybe the price tag. But until now, this lens is unique, reliable, lightweight and producing fantastic images. I have to buy a lens mug to accompany it with me even when I'm not using it.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Lightweight, Strong Construction
Excerpt: A beautiful lens with fast autofocus. Great for outdoor use but not so great in low light but the image stabalizer helps if you do need to use it at a low shutterspeed, works well at 1/50th but have even got sharp images at 1/20th. The lens is a lot lighter than it's 2.8f counterpart which for me is a plus as I shout for the whole day and a tripod slows me down.
Pros: Durable, Fast / accurate auto-focus, Lightweight, Rugged, Sharp, Strong Construction
Excerpt: I have always enjoyed shooting w/telephoto zoom lenses on Canon film slr's. I now shoot almost exclusively in digital. I particularly like the not-so-intrusive reach a telephoto zoom offers. Great for candids. The Canon EF 70-200mm f/4.0L IS USM lens is my first L-series lens. I have to admit this has been a wonderful purchase! I have it paired w/a Canon EOS 50D.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Rugged, Sharp images, Strong Construction
Summary: Debated between this one and the f2.8 for wayy too long. Decided on the f4 for a few reasons - weight (MUCH lighter), cost (DUH, it matters) and honestly after having rented both, the f4 is a tad sharper. Since I knew this would be my most used lens, the weight is what swayed my decision. LOVE IT!!! If I shot more weddings, I might have went with the 2.8 but that is a beast and not one I would want to carry at a long shoot or on day with several shoots.
Excerpt: I bought this and quickly had buyers remorse....I should have sprung for the 2.8L. I ended up trading this in to Adorama for the 2.8L. I took a bath on the trade but needed the extra speed to photograph indoor college tennis.