I just joined and found this thread. I have tried a body cap pinhole and it reflected way too much light (light scatter made a trippy blur effect though!). I've made quite a few pinhole cams myself, from anomorphic to solargraphs.
There's a program that I find helpful, it is on this site. I don't have anything to do with it, just that I had downloaded it, and used it. The math of the proper aperture ratio to the distance to the film plane is way beyond my tiny brain, so this app helps me figure out the optimal diameter of the pin.
I hope that link works properly.
Yes, most suggest using an aluminum soda can:
- I like to cut into a triangle shape, easier to tape into place (less edges for light-leaks)
- sand with the finest sandpaper you can until it is as thin as possible while still opaque
- use a tiny sewing needle to make a ROUND hole. Spin the sewing needle or the aluminum.
- sand the hole to smooth out again
- apply to camera/body cap. I use black gaffers tape to attach, so no shiny aluminum will cause internal reflections.
- shoot & enjoy!
If using a body cap... Yes, I'd suggest making a fairly large drill hole in the cap. Then, use a small piece of soda can, and attach the above homemade pinhole to the body cap for use. The body cap is simply TOO THICK to make a good pinhole. You'd have to dremel out a serious countersink in the outside of the cap to allow the proper light rays in. And, IMHO, it would likely melt the plastic into a mess more than it would succeed in making a great pin.