Strange Lens Issue - Need Help

[Trevor Ash]

I'm having a hard time understanding the problem. Is autofocus involved? I'd just send the camera and lenses back to Canon for adjustment with a good explanation of your problems. Unless you're worried about shipping costs or time without your camera better to do it now and get it over with.

[JK_Photo]

I've read about problems such as this on some review sites. I think it may be what's referred to as "backfocus" or "frontfocus" or some such thing.
Basically the lens is focusing just in front of or just behind the point where you have locked focus thus giving you a blurry shot. It can be fixed by the manufacturer with some sort of adjustment.
Try doing a search on the issue and maybe you can suss the problem out for yourself before sending it in.