From thingiverse description:
The P5 is designed around a 4x5 film holder, widely available used or surplus. Film holders have a "dark slide" that protects unexposed film/paper from light, so the rubber band to close the shutter is not necessary (or desirable for long exposures).
Using the proven Pinhead shutter design, and lacking any film transport mechanism, the shutter blade is the only moving part.
Specifications:
- 90mm focal length
- designed for a 0.40mm pinhole
- f-stop of f/225
- 70 degree field of view.
http://www.thingiverse.com/thing:143882
http://www.flickr.com/photos/theschlem/sets/72157635388826290/