I wrote these up for some 35 mm pinhole cameras I gave away recently, some for world pinhole day -- if you can use them, feel free.
-- pw Pinhole Camera Instructions You hold in your hand a pinhole camera, lovingly hand-crafted from a cheap give-away camera. I carefully removed the lens and shutter, and replaced the lens with a piece of aluminum pop-can with a tiny hole in it. Now you can take pictures with it. General instructions: * Load the camera with 35mm film (color print film, ASA 100-200, will probably work best) * Find something to take a picture of * Set camera down on a firm surface, or hold it against something * Open front flap (or remove lens cap) (this is your shutter) * Select an exposure: Conditions Exposure Sunny 2-4 seconds Partly cloudy 4-10 seconds Shady 10-20 seconds Cloudy 10-20 seconds Night 15 minutes, 1 hour, 2 hours, 4 hours Inside, sunlit 1-4 minutes Inside, light bulbs 2-10 minutes Inside, dim 15 minutes, 1 hour, 2 hours, 4 hours * Count out loud "one one thousand, two one thousand, three one thousand..." to count seconds to time the exposure (use a watch to time longer exposures) * Try not to move the camera during exposure (unless you want to) * Close front flap/replace lens cap (e.g. Close shutter) * Press button on top of camera * Wind film until it stops You've Taken a Pinhole Picture! If you're not sure of the right exposure time, try taking two more pictures of the same thing: one for ½ as long, and one for 2-4 times as long (this is called "bracketing" your exposure). Only changes of at least this much (1/2 or double) are likely to make much of a difference in how your picture turns out (that is, a 30 second and a 35 second exposure will both look about the same on film). So, reasonable exposures might be (s=seconds, m=minutes, h=hours) 1 s, 2 s, 4 s, 8 s, 16 s, 32 s, 1 m, 2 m, 4 m, 8 m, 16 m, 32 m, 1 h, 2 h, 4 h, 8 h, 16 h, 32 h However, film doesn't absorb light as fast during a long exposure (longer than a minute, typically, although it varies from film to film). This is called "reciprocity failure" and happens because films are designed to work best when exposed to light for between 1/1000 of a second and a couple of seconds. Really short exposures, and really long exposures, wind up requiring more light that exposure times in the films' "sweet spot." If in doubt, give an exposure more time than you think, rather than less. Theory and comments: What is a pinhole camera? The simplest camera, a hole in a box. How does it work? Light travels in straight lines (ok, gravity can bend light, but that's not going to influence your pictures). With a small enough hole, light from one spot in the outside world travels (in a straight line) to one and only one spot inside a pinhole camera the pinhole stops all the other rays Why bother? Pinhole cameras are a little bit of magic you can hold in your hand, the simplest way possible to get a picture. No lens, no battery, no electronics, just a box, film, and you. Pinhole pictures show the world in a unique, luminous way, that lens cameras simply cannot match. They let you take a picture of time passing seconds or minutes rather than the fraction of a second, the frozen moment, normal cameras show. Lights move, people and cars disappear, trees wave, all captured, slowly, on film. Pinhole cameras have another curious property: whereas lens cameras have to be focused to form a sharp image, a pinhole camera shows everything, at any distance, equally sharp (or equally fuzzy). So you can put a pinhole camera next to your foot, and get a picture of your foot and the statue of liberty at the same time. You can't really say they're both in focus because pinhole cameras don't focus! If I use a smaller pinhole, will my pictures be sharper? Yes, to a point. Larger pinholes let more light in, which means shorter exposures, but fuzzier pictures (more light hits the film from more parts of the outside world, blurring the image). Smaller pinholes let less light through, forming a sharper image until the pinhole gets too small. Then the wavelengths of light start to bunch up at the edges of the pinhole and interfere with each other, causing diffraction, and blurring the image. One great thing about pinhole cameras is that, because they are so simple to make, you can make a lot of different kinds of cameras easily. Want a camera that takes really BIG pictures? Find a fridge box and a roll of photo paper (that'll work to make a negative, but you'll need a darkroom to develop it). Want a camera that takes a panorama, or looks in several directions at once, or has several pinholes? Easy with some cardboard and some black masking tape (most art supply stores have this) you can build these. You can make a camera that takes round pictures, or takes pictures on curved film, or whatever. Common problems: * Pictures too dark: leave shutter open longer * Pictures too light: close shutter sooner * Picture fuzzy/blurred: camera may have moved * Light streaks or blobs: camera may have a light leak, letting light in from the wrong places. Keep the camera out of bright light when you're not using it, and cover the seams of the camera with black masking tape if necessary * Picture is round, with a sharp edged black circle around it: this is vignetting, which happens when part of the camera blocks the pinhole from seeing the whole picture. This can be difficult to fix without rebuilding the camera * Picture is good in the middle, but fades to black near the edges: this is falloff, which means that at the edges of the film, the same amount of light has to cover a greater surface area, which leads to a dimmer image at the edges. This is normal, but you probably won't see much of it with small cameras. * Pictures are odd or unexpected: Serendipity is pinhole photography's middle name. The best pictures are sometimes unexpected! __________________________________ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com
