I use this lens quite a lot and it is mostly a good performer. Focus is always spot on. Build quality is up to the usual Tokina standards (there doesn't seem much plastic in it but I can't say if my assumption is correct). The only issue with the lens is a certain amount of chromatic aberration at the edges of high contrast subjects - but not enough to put me off using it. Another plus is the fact that, at 17mm, it will cover a full-frame sensor - so I've been told. For the money it is excellent.