Excerpt: This is an excellent lens, very sharp, very fast, and of solid construction (although, as others have pointed out, not up to L caliber). It is a great lens especially for the price but there is one caveat - it suffers from marked lens flare.
Excerpt: I'm a very casual shooter, and only occasionally take photos that are paid jobs. I got the lens since I value a large constant aperture over longer range like Canon's 15-85.I upgraded from the standard 18-55, and find I have more photos now that are out of focus, or mis-focus; however I don't know if this is due to the narrower depth of field at f/2.8, combined with personal bad judgement through the viewfinder, OR if the autofocus with this lens has a problem.
Excerpt: I researched a lot and tried to figure out which lense would fit my needs without breaking the bank. So far so good, no creeping like others have stated, build not the same as my 24-105L but this is solid. This lense will be on my 60D 90% of the time! excited to do some portraits with it. Worth the money if you have a crop sensor camera.
Excerpt: My most shots are outdoor of plants and wildlife. Recently, I shoot some indoor activities, such as musicals, plays, meetings, awards, etc. I use the lens with Canon T4i camera. I am struggling and learning. I had some good shots and some not so good shots. It could be due to my inexperience of indoor shooting. I wish the lens comes with more instructions and references.
Pros: Easily Interchangeable, Fast / accurate auto-focus, Strong Construction
Excerpt: I bought this to replace the 18-55 f/4-5.6 IS II kit lens from my T3i. The 17-55 is leaps and bounds a better lens. And for the price it better be. Honestly that's my only complaint with this lens. That's only reason it gets 4 stars instead of 5. This is L series cost, and the glass may be L quality, but the construction isn't. While it is much better quality than the kit lenses, it isn't near that of most L lenses.
Pros: Color Transmission, Consistent Output, Durable, Fast / accurate auto-focus