After seeing some of your shots with this lens, I was tempted to purchase a few months back. But then I read reviews on FM
http://www.fredmiranda.com/reviews/s...&cat=37&page=2
For me there were too many people getting AF problems, so I decided against it. Have you considered you may have a problem with the lens. Might be worth going back to shop & trying another lens to see if problem is across the board or hopefully just yours, which you can get repaired / replaced