Ok, I sold my well cared for D7100 on the auction site, sent well applied via RMSD. Camera has around 10,500 shutter count. The buyer has come back with a problem .He states that around 50% of all the shots taken are completely black, and also when moved onto his PC. He has tried a different lens but problem is persisting although there seems to be no pattern to it, He goes on to say he shot a couple of hundred images this afternoon using both lenses and that probably 150 are fine, but 50 or so are totally black. The black pictures seem to occur in bunches then the camera will be fine again for a while before another bunch of pictures come out black. Sounds to me like a mirror/shutter problem. Maybe Royal Mail has been playing basket ball with it........ I'll give it a good look over when I get it back. Anyone know of any recommended repairers before I give Nikon 300 quid?