hi theo

in addition to the killer advice whitey gave you ...
if you dispose of your camera, GRAB the empty rolls !
it takes 122 size film for "post card" format ...

i use mine for paper negatives ...
you trim one of the long edges off of a sheet of 5x7 paper
stick it in the back of your camera and close it works every time!
i have also gotten into the habit of rolling my own spools of
paper and making paper negatives that way ...
(you have to have more than one spool to do that trick )

great format, have fun !
john