I have already returned my 7D that I got in November 2005 to KM twice. After working correctly for a few shots, the autofocus starts overshooting and fails to lock in to a crisp focus. At this point the circle in the bottom left of the view finder flashes indicating that there is a focus problem and the shutter is locked. Initially, the problem is intermittent and then becomes permanent. Each time KM says they have returned the camera to factory specs.
Most recently, I got the camera back a week or so ago, checked it out and it was working. Saturday, I took it out on a shoot at a funeral and with in three shots the problem reappeared. The problem occurs with all of my KM lenses. The most recent issue was with my new KM 28-75 f/2.8 lens, so it is not a lens issue.
I have had no problems with my Maxxum 5D that I bought as a backup to the 7D.
When it works, the 7D is great. However, this is getting very old and expensive, since I have to pay the cost of returning the camera, with insurance, each time to get it temporarily "fixed". :sad:
Has any one else experienced this problem? Any suggestions?