Excerpt: This was my first zoom lens and I have to admit that I was pleased with it when I first bought it. Since then I have upgraded to the Canon 18-200mm and WILL NEVER go back to this lens. The difficulty it has with low (even lower) light conditions is pathetic. I have trouble just getting it to focus on the subject within my livingroom which has a bay window, glass door and secondary window (ie. enough light).
Excerpt: This is a great lense for common pics but not for surfing photos[...] If you are taking Surfing photos do not listen to the people who do not take surfing photos! You will need to purchase a 400mm or larger for Surfing Photos! The larger telephoto lenses have a significant cost so start saving if you want great surfing photos![...] More than a 400mm telephoto is better in regards to shooting great distance action pics like Surfing.
Pros: Consistent Output, Easily Interchangeable, Fast / accurate auto-focus, Lightweight
Cons: Image stabilization so so, Poor in Low Light, Slow Focus
Excerpt: I do a lot of hiking so I wanted a light weight package to keep equipment weight down. I find the focus tends to soften in 250mm and you really notice the change in aperture. Using a haze/UV filter on this lense tends to really darken the shots, forget using a polarizer in all but the best lighting. I have gotten some amazing shots with this lense but I am still found wanting more.
Summary: I read the full review of this lens in Canon magazines and thought this is the one for me, new lens released July 2011. How wrong can you be - attached to my Canon 50D off I went, not good results. The only way I can explain if that the lens is "soft focus" not sharp at all. Very disappointed. I did try this along side my Tamron 18-250 and the Tamron won.