Here’s something that happened to me the other day that I thought I’d post about in case it happens to anyone else.
I was out shooting and the AF overlays were not showing on the screen (either the frame or the dancing boxes). I tried turning on/off, pulling batter, changing AF modes and nothing. For some reason I tried switching the IS mode on the lens (200-600) and they came back, but as soon as the camera went to sleep it was the same thing.
At this point I was I thought I was going to have to put in a support call and luckily I noticed that the drive mode dial was in between H and M. I somehow managed to hit the button and move the dial halfway. As soon as I selected and actual mode everything worked again.
Anyway, probably a 1-in-a-million chance of doing that by accident but thought it was good info to share (even if not the best thread to share it in)