In photography, an extremely simple camera ? a box having no lens other than an extremely small aperture. It's a great, inexpensive, hands-on means to learning the basics of how a camera works.Don't be misled by the size of the fisherman; a pinhole camera can be as large as he suggests, but most are about the size of a shoebox. Exposure time is dependent on the size of the camera (distance from lens to film), the size of the pin hole, the sensitivity of the emulsion, and the brightness of the ambient light. The average pin hole is .02 inch. The diameter of the average pin shaft is .025 inch. A small pin hole, (just the tip of a pin) is likely to be .015 inch. A hole of about .02 of an inch will require an exposure of about 1 minute using RC Glossy photographic paper as a negative, but if the pin hole is a little smaller (.015 of an inch) about 2 minutes is necessary. A smaller hole is better because the smaller the hole the longer the exposure should be; the longer the time, the less problematic a mis-timing of a few seconds will be. To attain greater precision, figure the lens's f/stop. You can do this by dividing the distance of the hole to the emulsion by the diameter of the pin hole. The dividend is the f/stop. Knowing the f/stop (usually around f/200), use a hand held lightmeter to take a light reading, and calculate the exposure time. [Thanks to Wm. Rapf, Souhegan High School, Amherst, NH.]Before making one that uses photographic paper, you may want to try this simpler one that utilizes tracing paper. For this type (thanks to Konica of Japan), all you need is a milk carton, scissors, a black marker, a pin, tape and some tracing paper:Other resources concerning pinhole cameras: Yahoo's list of sites concerned with pinhole photography. Also see camera lucida and camera obscura.