Today I would like to show you one of the simplest pinhole cameras I know. It is a Katatumuri 6×6 cardboard camera; it uses 120 film rolls yielding twelve shots of 6×6 format per roll and has a pinhole ø= 0.25 mm, the focal length to the center of the film is of 32 mm and that gives an f/128 value. It is commercially available through the internet; if someone is interested just search for “katatumuri”.
I am really amazed of the quality of the pictures it produces and of the simplicity of work. The shutter opens and closes by displacing a piece of cardboar that hides the pinhole (you may see it in the two last pictures). Another plus is that you build yourself the camera from scratch just using the preformed cardboard pieces and some glue.