A pinhole camera is the most basic type of camera: a light-tight box, a piece of film or photographic paper, and a small hole to let light in. Pinhole cameras produce images like no other camera, and offer a lot of room for experimentation. They are also easy to make.

What is a Pinhole Camera?

The basic principle of the pinhole camera is a dark room (camera obscura in Latin) or light-tight box, with a small opening on one side to let light in which is projected onto the opposite wall. In an actual pinhole camera, this is where a piece of film or photographic paper is placed, but pinholes were and still are also used to project images like that of the sun. As early as the tenth century, experiments with pinholes were made, and in the Renaissance, the camera obscura was a popular form of entertainment and also a tool for artists to better understand perspective.

The obvious difference between the usual cameras we use and pinhole cameras is the lack of a lens. A lens gathers a lot more light on its large surface than a tiny hole, and so a pinhole camera requires much longer exposure times. It also provides almost infinite depth-of-field, though, which makes images possible that would not otherwise be.

But the most interesting part is really building such a camera. While it is possible to buy one, I would strongly advise against that. Building a pinhole camera is easy, and taking pictures with a camera you built yourself has a completely different quality than using a bought camera.

Building a Pinhole Camera

A pinhole camera can be built from almost anything. Popular objects are shoe boxes, film canisters, tin cans, and old box cameras. The main questions to answer are:

Do you have a darkroom? If yes, your options are really unlimited. If no, it makes sense to build a camera that takes roll film, which can then be processed by a lab. Also, loading and unloading the film should be possible in normal light conditions, which is not the case with most shoe box or tin can cameras, for example. A darkroom is certainly not required for building your own pinhole camera, but it does help being able to quickly process and print your first roll of film to see if there are light leaks, how well the exposure works, etc.

Film or paper? Shoe box cameras are usually loaded with a piece of photographic paper, which needs to be loaded and removed in a room that is completely dark (perhaps with a safelight). The paper is then developed into a paper negative, that needs to be copied onto another sheet of photographic paper to get a positive. This process is easy to do when you have access to a darkroom and want to do some quick experiments, but is unworkable otherwise. Paper negatives also don't have nearly the dynamic range of film, and produce very flat images with little contrast.
Film is a much better choice, but does require a more sophisticated camera. The exception here is a film canister that can be loaded with a piece of film cut from a roll, but which essentially requires the same infrastructure as using paper. Roll film is much more practical, because it is possible to take many pictures and change film in the field, rather than having to head back to the darkroom after every shot.

Once you have decided on the type of camera to build, it is easy to find materials to make it from. I made a camera out of an old Agfa Clack box camera, which I call the Loch-Lomo. A camera made from an iPhone box (which is black, and thus very well suited for this purpose), dubbed iHole is a slightly more stylish option. Justin Quinnell makes cameras out of "pocket film" (110 type) cassettes, which he uses to great effect to shoot pictures from the inside of his mouth.

A Different Perspective

The special properties of pinhole cameras make it possible to explore new perspectives that one would not otherwise have tried. The infinite depth of field and often wide angle of view make it interesting to put the camera on the ground, where it can see objects that are very close as well as ones far away.

Many pinhole cameras lack a viewfinder, and if they have one, it may not be very precise. Also, shoe boxes and film canisters don't have tripod mounts, so placing a camera precisely is difficult. Their low weight and negligible value makes it possible to put pinhole cameras where other cameras don't usually go: on top of bushes or rocks, on the ground between walking people, mounted on boomerangs, etc. 

The inherently long exposure times also produce interesting results, though similar effects can of course be achieved with conventional cameras. A camera like the Loch-Lomo has an effective f-stop of 1/256, so even in bright daylight, exposure times of less than one second are very rare. Because of reciprocity failure (see below), long exposure times become even longer, making exposures of hours, days, or months possible.

Water is especially interesting in this case, because its constant movement tends to create very pleasing effects with long exposures. Most images look as if the water was frozen, its surface looking like nacre.

Pinhole cameras provide a lot of room for experiments, and they really require experimentation. Simply making or buying a camera and trying to take the same pictures as with a regular camera won't lead to interesting results. But experimentation is what photography should really be all about!

Examples

Examples of pictures taken with pinhole cameras are easy enough to find, but one needs to be aware that one or even a set of pinhole pictures is not representative of all the things that can be done. There are different approaches, and the resulting images are quite different - just like with a regular camera!

A few examples are my own pinhole pictures on Flickr, the Worldwide Pinhole Day Gallery and pictures tagged with pinhole on Flickr, and of course Justin Quinnell's brilliant pictures.

Exposure Time Correction

The long exposure times used in pinhole cameras require some extra attention. Starting from about one second, the exposure no longer increases in a linear fashion, but needs to be corrected to account for the reciprocity failure or Schwarzschild effect. The following table gives the corrected numbers the Agfa Pan 100 (APX 100), but should work for any ISO 100 film, black&white or color (I have used these times with APX 100 and Fujicolor 100).

This table was prepared based on the following formula (thanks to Dieter Lefeling): tc = 0.1*(10*tm)^(1/(1 - lg 2)) (where tc is the corrected time, tm the measured time, and lg the base 10 logarithm).