At its simplest, a pinhole camera is just a light tight cardboard box with a piece of aluminium pie dish containing a pinhole to expose the film or photographic paper.
Of course you need to design a shutter, (your thumb will do), some way to hold the film in place and a system to seal up the opening where you put the film in the pinhole camera.
There is no viewfinder; you just point the pinhole camera in the right direction. You can draw some lines on top of the camera to indicate the field of view.
Exposure times for pinhole photography are usually measured in minutes.
Work out your exposure by the hit and miss method, also known as exposure determination by experimentation. This is where you say “Ooooh. I reckon about two minutes.” Then if it turns out ok, well and good. But if it’s not right, you either double it or halve it for the next exposure, depending on your assessment. Nothing wrong with that method for pinhole photography.
Let’s say you’re using 4″x5″ photographic paper. The diagonal of your paper is about 160mm. If you make the distance from the pinhole to the paper about 50mm to 80mm this will be ok. Length of about half the diagonal of the film. You could make the length 20mm to 50mm giving quite a wide angle. There’s nothing to stop you building your pinhole camera around a four foot length of drainpipe giving you a 1200mm telephoto pinhole camera, except that the exposure time might be in the order of several hours or all day.
My best pinhole cameras have used 8″x10″ film and have a length of 50mm to 70mm. Everything is in focus from 250mm to infinity. Angle of view is around 135 degrees.The light runs off at the edges of the image.
Note: 100mm = about 4″
There is much more technical stuff that can be studied but that’s all you really need to know to get started. So empty the breakfast cerial packet and build a pinhole camera.
You can use pretty much anything light tight to make a pinhole camera: biscuit tin, breakfast cerial packet, 20 litre oil drum, golden syrup tin, jam tin, match box, black ice cream container etc. etc. Would you believe you can even use your mouth?
Yes, in the darkroom put a short piece of 35mm film in your mouth and close it. Go outside and press the aluminium with the pinhole firmly against your lips, then open your lips for about 10 seconds keeping your head still. Reverse the procedure. You can work out the rest for yourself.
Consider whether it will be better/easier to use the end or side of your tin/box.
If you use a jam tin you can use alfoil and a rubber band for a lid.
Use black paint inside a shiny tin if you have some handy.
Invent a shutter. Black plastic and masking tape will do.
If you decide on a jam tin or golden syrup tin with the pinhole in the side, consider using a baffle that springs tight against the sides of the tin to fasten your film too. A piece of plastic milk bottle will do.
Handy items to have around are: breakfast cerial packet, masking tape, blue tack, plastic milk bottles, rubber bands, alfoil, scissors, knife, glue.
Your pinhole camera will give a negative image on your photographic paper. In this modern, computer age it will be possible to scan, change to a positive and computer print.
An SLR camera can be used for a pinhole camera simply by removing the lens and attaching a pinhole with black sticky tape.
If you are making a pinhole, look for the smallest needle in the set.
It’s important to have a smooth, burr free pinhole for the sharpest possible image. Ideally, push the tapered section of the needle through in several stages, gently removing the burr with fine wet and dry paper between actions. Rest the foil on cardboard as you push the needle through so you don’t stretch the foil.