Summary: The photo quality isn't bad, my problem is that my lens is faulty after 5 months. I constantly get errors on my Canon 5D MKIII with this lens. I contacted Tokina USA and they are fully aware of the problem. The aperture gets stuck. They said I need to send it to them on my dime to recalibrate it.
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.