Was wavering between the Canon 15-85 or the Sigma I choose the Sigma for the 2.8. UPS just delivered it I was excited slapped it on my 7D the focus will not lock. It just sits there cycling back and forth, turned OS off no difference. Made some changes on my camera didn't help. I even went as far as cleaning contacts no good. Now I have to wait until tomorrow to talked with the place I bought it from who is on the east side. I hope they will do something about it as I bought it on Fleabag, but I got it from 47st which I have used many times in the past.