With my Instamatic 500 I cut the 'finger' off that detects the sprocket so I can use unperforated film (mostly bulk Kodak 160NC, some Rollei Retro 400S). I wind 1.5 times per frame for the proper spacing or 2x to be sure. I put the shutter at 1/500 and f/22 and take a picture on my arm for the in between shot, still gets some light leak once in a while, wish I had a lens cap for it but it's a 32mm Retina size and lens caps are more than I paid for the camera! Can take some fun continuous shots as well.