I've had my eye on this old tube of Oats for a while, thinking it may make a decent #pinhole camera.
I wanted to try and position the pinhole at the focal point of the circular arc formed by a curved film plane. In that way, focal length will remain the same across the sheet of film; widening the angle of view and reducing vignetting.
Two halves of the cardboard tube interlocked to form the rounded back of the camera body.
A film sleeve has been fashioned from off cuts of the cardboard tube, and glued into a centered position to the inside of the camera body. A 4x5 sheet of film is being held by the sleeve.
Initial cuts of the cardboard tube. It has been split horizontally across the cylinder, then the bottom portion split in half vertically.
A sacrificed sheet of 4x5 film sits inside of one of these halves.
Large cardboard tube that used to contain HEB brand Old Fashioned Oats.
Grid lined paper with sketches of what a curved film plane pinhole camera may look like if made from a halved tube.
I include this for the diagram illustrating that the focal length will remain the same across the film plane if the pinhole is placed at the focal point of the curve formed by the film.
Oathole! Over 2 years later I somehow returned to this 4x5 pinhole project. Stumbling on it while cleaning, I realized it wasn't far off from completion so grabbed some gaffer tape and took it across the finish line.
Cover fully on the base with the pinhole visible. Effectively open shutter position.
Cover partially slipped on the base demonstrating how it can act like a shutter.
Cover and base separated. Black gaffer tape is covering all seams.