Summary: Am just an amateur and picked up a T4i with the 40mm pancake lens a few months ago. Thought this would be a better all purpose lens than a stock Canon 18-55mm. Read many reviews and took a chance on this one. Sample photo quality so far is more than adequate for my purpose with good true colors.
Summary: The lens is all right for the price. I had this on a D7000 and the quality is not even close to the Nikon 35mm 1.8 lenses. It is a decent and cheap walk around lens. The "OS" works relatively good, focus is pretty accurate. Not much hunting. Speed is ok, not super quick.
Summary: Ill make this short and sweet. I got this because I wanted a kit lens replacement. It does that relatively well. Being able to stop to 2.8 is nice. The colors are pretty accurate and the sharpness is ok in the center. My one major gripe with this lens is the barrel distortion. Wide open at 18 mill.
Summary: After reading several review site and reading a good comments i decided to give a chance to this lens from Sigma but my results are not that great as i was expecting... The Image Quality it is not better than kit lens (Canon EFS 18-55 IS) in all focal length.
Summary: I bought this lens 1.5 years ago, and it was my main lens. Used it a lot, traveled a lot with it. but suddenly my camera (nikon d90) started to show the "F--" error and now this lens stopped to work. Sad I live in brazil and I forgot to register mine for the extended warranty.
Summary: Been using this lens for about a week now. Overall performance is Ok. The photos come out fairly sharp. However, when I switch over to my canon 50mm 1.8, the sharpness is way better than this lens.
Summary: I really wanted to buy this lens. Unfortunately, my kit lens (Nikon 18-55 EDII) is a lot sharper than this!! I tried this previously at a local trade show. Although the build quality seems very good. It appears very soft at f/2.8 across its entire zoom range.
Summary: I've owned Sigma before and this is yet another lens from them that has the front focus problem. I used this on the D200. I own the Sigma 24 1.8 and I had to send both the lens and camera body to Sigma to fix the focusing problem. I just don't want to bother with that any more so I returned it.
Summary: I've bot this lens and was soon disappointed. With all the great value (good zoom range, image quality and 2.8 aperture over the whole range for the price) the lens suffered from terrible front focus on my Digital Rebel XT. Interestingly enough, my friend's Canon EOS 30D didn't have the problem.