Hi again everyone. I posted a week ago or so wonering about an AF problem. Nothing has been resolved, and Canon now has the camera. They want $211 just to see what the problem is. I bought this used and the original owner says he never had a problem. Here's my question. Is there any reason for a brand new 50mm 1.8 II, not to work on a 40d? The original owner says he has the same lens and it worked fine. He says the 2 lenses that don't work for me (the 50mm, and a 18-55) are the problem. I say since the lenses work on my XT, the camera is the problem. I feel like I'm being taken here. Any help would be great.