to add onto rochkoh's post, just go to any pro shops (CP, fotoguide, ruby photo) and ask for 120 film. that's the medium format size. but like 35mm film there's a whole range of 120 films (ISOs, slide/neg, colour or B&W, chromogenic, etc etc) so do some research before going down otherwise sure dam blur one. but generally there's a 120 equiv. for most f35mm film types (e.g. ilford XP2 comes in both 35mm and 120 film size)