Truzi, my advice to you is to use yarn but yarn of a narrower gauge. While I am at it, I never snap shut backs on SLRs because doing this over and over again grinds the latch so that there eventually becomes a bit of 'play' that can cause light leaks. Do this, instead: Pull out the rewind crank fully and while you are holding this open, with your other hand (thumb on back and index finger on front of body) firmly press the back to the body. Only then do you release the rewind crank. This way there is no grinding of that rather delicate (and too fragile, in my estimation) latch. - David Lyga