Takes fantastic "L" quality shots. I can finally get wide shots up close. The only downside is the build quality. It isn't top of the line for ruggedness. I've heard that dust can get I side the lens, but I haven't had any issues myself. Overall I'm extremely happy with this lens.

I bought this new 17-55 f/2.8 IS lens to replace a previous one I purchased in early 2011. Over 7+ years I took about 16,000 images with the previous lens, about 1/4 of all my photos. The previous lens stopped focusing about a year ago.

old f3.5-5.6 wasn't fast enough to catch a 2 year old... this seems to have done the trick in low light! haven't really tried it out apart from that due to work and foul weather! so far so good! replacing kit lens.

Sharp Focus; Strong Construction

Great lens, takes sharp pictures, great low light quality. Kind of expensive, but cheaper than L class. Heavy, but good heavy(glass).

Consistent Output; Easily Interchangeable; Fast / accurate auto-focus; Nice Bokeh

Expensive; Heavy

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.

Pros: Fast / accurate auto-focus, Consistent Output Cons: Other thoughts: I've been using a Tamron 17-50 f/2.8 lens for a number of years but really wanted a lens that focused faster and more accurately, especially in low light.

This lens is fast and sharp. It replaced a Tamron 17-50 DiII VC. Incredible difference especially in low light. The only thing I miss is the zoom lock, but I can live.

Consistent Output; Fast / accurate auto-focus; Nice Bokeh

Lens Creep

This lens, even with the EF-S format and inferior build quality, produces surprisingly good images, outcompeting even such "L" lens as 24-105/4 L IS USM. Particularly related to chromatic aberrations which in this lens are neglegible.

Super-sharp images

Poor build quality

Canon makes two distinct lens ranges. The EF lenses will fit any of the EOS bodies, but the EF-S lenses will only fit Canons with the smaller APS-C sized sensor. That includes the EOS 1000D, 400D, 450D, 40D and new 50D.

I've had this lens for 5 months now and I find it to be outstanding. My photo's are extremely sharp, vibrant and colorful. The focusing is fast, though not as quiet as an STM and works beautifully. I use this lens with the 70D and recently went on a trip to Jamaica ..