Summary: OK, I like it. My first few test shots were OK. But when I went to shoot a photo session, at f/2.8 (this is why I both this lens to shoot at f/2.8), after zooming the photo I was WTF! The focus was so out, the face was completely blurry.
Summary: My one has focus issue. When I use it for shooting, sometimes(not at all) it stop auto focusing, I must be waiting few seconds, or turn off and turn on camera. this issue can be resolve at that moment.
Summary: I needed a wide angle lens for indoor architectural shots. There are a million reviews of this lens out there, I won't rehash them. Bottom line, there are few wide angle lens' out there at this price point. This lens, for the price, is worth it.
Summary: I purchased this as a more affordable alternative to Canon's 16-35L, which I rent often. After using it for a week, I decided to return it. I really wanted to love this lens, but it's just not anywhere close to the 16-35L in terms of image quality.
Summary: I did find the lens to be sharp, but the flare made it unusable for me. I did one real estate shoot with it and found some of the shots to be unusable due to the flare from window light, it was sunny outside, but the window was not facing the sun so the amount of flare really surprised me..