In the far-off days of totally manual film photography, when I would lug around two film bodies (instead of nowadays, when I lug around two DSLRs!), I would use slide film in one, FP4 in t'other. There were film box reminder slots on the back, but as I 'rolled my own' from bulk, they were used for a folded piece of paper to make notes on (cunning, heh ?).
The problem of knowing which body was which (both Ricoh KR10 Super) was solved by colouring the Ricoh logo on the pentaprism with a red felt-tip pen on the body containing slide film. Incidentally, I was often asked the derivation of this 'enhancement' - my reply was usually that the depth of field on the body was greater due to a larger mirror.
BTW, Dave, the only discussions I've ever had with other photogs have been other Pentax users, when we congratulate each other on our good taste, and I try to blag a drink off them.
Last edited by 35mmfilmfan; 09-09-2017 at 02:53 PM.
Reason: More 'thoughts'