Some cameras like my Kodak X-35 don't need to sprocket holes to cock the shutter, but I do need to take every other picture with the lens covered otherwise I get overlapping frames. I have a few 126 cameras that I bought at thrift stores just to get the cartridges. I've reloaded them with 35mm no problem, but taking them apart is a pain. Also, you have to tape up the frame number window. Also, I put a layer of tape inside the cartridge as a sort of "pressure plate" since the 35mm film has no backing paper.