Hern
Established
You guys are reminding me of the M I didn't buy once. On the outside it was mint. On the inside, there was an actual depressed track worn by film into the pressure plate. It had been used on a tripod at Fort Dix during the Viet Nam war, and before, to shoot input IDs of soldiers. It was available cheap, but I held off because of the wear I couldn't see.
Marks left by the film? Garry Winogrand anyone?