My brother and my sister-in-law got me a Pinwide wide-angle pinhole cap for Christmas. It’s quite a neat little toy. Some of my favorite photos from my wedding were taken with a pinhole camera, and it’s nice to be able to convert my everyday camera to one on the fly.
It takes a bit of trial-and-error to get visually “readable” results, but eventually I started settling on exposures of about a minute at ISO 100 on my Olympus E-P2.
The lens itself looks like a sunken body cap with a tiny hole in the middle: