The problem: if I press the shutter button halfway down, it autofocuses, but when I press it the rest of the way down, the shutter actually actuates about 1 time out of every 5 clicks. This has happened for some time now, but not this bad, so I didn't think it was a big deal until I switched over the same lens & flash to my other 40D and found this problem was completely nonexistent in that one. This is under warranty, so that shouldn't be a big problem...but I want to know if anyone's had this experience before. This only happens (or happens most) in extreme low light. I understand that if the focus mode is in Normal, then it will wait to Autofocus before you can take a shot. However, in AI-SERVO, it shouldn't care if the shot is in focus...I'm always able to hit the button whenever and it will take the shot, whether in focus or not. I have the camera set in AI-Servo, and it will focus, but not always take the shot...whether in focus or not. Any ideas?