Comment by niccl

A few years ago a friend ran a camera shop. From time to time someone would come in with an SLR that wouldn't behave (long exposure, no exposure, nothing in viewfinder). He'd take it, tell them to go away and come back in an hour, then hit it on a telephone directory. 9 times out of 10 that would free the stuck/sticking mirror and everything would be fine. He had to tell the customer to go away, though, so they didn't get agitated seeing him bash their expensive SLR around