120/220 film exposes 6cm vertically. So a 645 format camera usually exposes 16/32 6x4.5 negatives (although some in years gone by could only fit 15/30). A square format camera exposes 12/24 6x6 negatives, and a 6x7 format camera (such as the RZ67) exposes 10/20 images. The Fuji 617 captures 4/8 6x17cm images.