A camera designed to accept a full (5x7 or 8x10) sheet of photo paper, primarily designed for solarigraphy.

A solarigraph is a very long exposure photo, taken on photo sensitive paper. Exposures are usually anywhere from one day to 6 months (from one solstice to the next). The result is it will capture the path of the Sun through the sky for the entire exposure, and a little bit of the foreground. The photo paper isn't developed, instead it is scanned/photographed to save it. The paper will continue to fade as it's exposed to light. Much more information is available on the Internet.

The cylinder has a slit to accept a piece of aluminum can with a tiny hole in it to act as an pinhole lens. The holder has many holes for mounting with screws or zip ties. The retaining ring is optional, but is designed to hold the photo paper in a more circular shape, and to keep it from shifting.