Originally posted by Vendee
Regarding using this device with the film back open, I think it will only work with older mechanical SLR's like my ME Super, MX and K1000. It won't work with my modernish Canon EOS 3 because the shutter doesn't operate normally with the back open.
Depending on the camera, you may be able to fool it.
With some cameras, the door pushes a switch in the body to let it know it’s closed. Jamming something gently into the hole will let the camera operate normally.
Some cameras need the film to wind, so you have to jam the switch and then spin the film sprocket between frames.
-Eric