There's a real beauty in long exposure photography. Hours and days and weeks and months and even years can be condensed onto a single frame, and that frame will catalog the constants in our fast paced and forever changing lives. However, the issue is that these photos can be difficult to capture using modern cameras. Most fancy DSLRs have a maximum exposure time of 30 seconds, and then to get any longer than that you have to use the archaic "bulb" function that'll kill your camera's battery in only a few hours. So what's the next option for long exposure photography? Build the camera yourself!
First, a little science. Anyone who has taken a basic photo course knows at least the basics behind film processing. The light reacts with the paper, and then chemicals alter the products of these reactions so that an image can be seen. Now throw that idea out the window. Funny thing about RC photo paper is that it reacts noticeably to light regardless of any chemistry you may add after the exposure. Its something to do with the silver ions and electrons and other things that bald guys who carry around calculators for fun would be able to explain. But what does that mean for you if you're not bald and don't carry around a calculator for fun? It's the key to your long exposures. If the paper is exposed much much much longer than any exposure time that would work with darkroom chemistry, a discernible image will fry itself into the paper. You can capture entire days this way: the sun can be seen in a trail across the sky and only objects that remained stationary for long periods of time will appear. This image can then be taken to a flatbed scanner and scanned onto the computer.
So all you gotta do now is build your own camera to put the paper in. Your camera can range from a basic shoebox with a pinhole to something with shutters and SLR lenses and all kinds of crazy things. For this instructable, I'm going to show you how to go crazy with it. Cool things can be captured by just opening up a lens and continuously letting light in, but what if you want an Arduino- controlled shutter that allows you to control when the paper is exposing and when it isn't? That's what I'm going to show here.
Step 1: Materials
This project is very VERY open ended, and some of the components really depend on what you can get your hands on, so keep that in mind. However, all of these things are very easily attainable.
First, the building materials:
3/8 inch wood
flat head screws and matching wing nuts (relatively small and about an inch long)
any SLR lens with rear cap (it is imperative you have this cap)
50mm SLR lens with cap (yes, my design uses two different lenses)
donor 35mm SLR camera
9 Volt battery
actuator (I got mine from the steering mechanism of a radio controlled car I got from the thrift store)
RC photo paper
Some kind of miter saw or miter brace
**** depending on the route you take with this, you may need additional tools to take your donor camera apart. a hammer always helps!
Other various workshop tools are always handy too. There is no right or wrong way to build something. And again, I stress that these are more along the lines of guidelines to an idea than instructions to building a refined product. Go crazy with your design!