Summary: This is a nice wide lens. It focuses ok on my Sony a77. Even in low light. One can't complain with the performance. Light weight and I can use my Cokin series P ND grad on it with no problems. It is soft on the corners and gets worse as I get wider but not a deal breaker for the money.
Pros: Light weight, foucuses nice in low light, can use Cokin P series ND grad, minimum vignetting.
Summary: This lens is my ultra-wide workhorse for my a700. It's very similar to the Tamron version which is priced a little cheaper. It comes with a petal lens hood and unlike some other ultra-wides the front element doesn't protrude so much that it prevents a filter to be used.