I found these plans for a paper pinhole camera that looks like a boxy 35mm SLR. The plans were originally published in a Czech engineering magazine during the Soviet era. Conveniently the pdf includes instructions in both Czech and English. It was a pretty easy build. I'm about 90% done with it. The hardest part was smoothly popping the end off an empty film canister so that I could reverse the spindle to receive the exposed film (I used a bottle opener). I pasted the printed pattern onto some black posterboard before cutting it out, but I think I'll also tape over all the edges with electrical tape before my first shoot. Hopefully I'll post some pinhole images soon.
Would you say this squirrel has been eating flesh? Check out the bloody teeth (click image to view larger).
focal length: 23.8 mm (142.8mm in 35 mm equivalence), aperture: f/3.5, shutter: 1/160, distance: ~0.5 m
I took this on Boston Common. Those squirrels have clearly learned that people won't hurt them and might even give them them food: he was only about 2 feet away from the lens. I didn't feed him.