This Instructable will help you build an adapter that allows you to make use of those old, film-based SLR camera lenses you have gathering dust in your basement. It also allows you to take pictures in an automated way (think time lapse, security or what I had in mind, a camera for entry level astrophotography). Gather up the following (many will have these laying around the house):
1) A working Raspberry Pi (you can choose the model you want, I had the RPI 2 model B, but I suspect you can use any model
2) RPI camera V2 (you might be able to use the V1, but I like the quality and features of the version 2). I picked the NOIR camera because I didn't want to filter out infrared on my astrophotography.
3) keyboard, monitor and power for the RPI. Google it. I would recommend an HDMI monitor, but I can understand using others.
4) An old camera lens. In my case, I used an old Olympus lens. The important thing is to have the REAR lens cap. But even if you don't have that lens cap, you should be able to find one at a local camera shop for pretty cheap.
5) A trap adapter - 1.5" (see picture) this is available at the local hardware store for a buck and some change. It includes two parts. If the one you find is too expensive, get the next size down. You might have to improvise some of the assembly though.
6) An old tripod that you don't use very often (don't worry, I won't cut it up).
7) Tiny plastic screws (x4) that fit the RPI Camera and nuts to match. My electronic store had these, but they might have them at a hardware store. If you have to use metal ones, you might want to put some electrical tape around them (pretty cozy, though). During experimentation, i used insulated wire.
8) A laundry detergent cap. I picked one that the plumbing part fits inside. I think you could also use a kitty litter cap.
9) A handful of zip-ties.
Step 1: Begin Prep Work - Drill Out the Lens Cap
Take the BACK lens cap and drill a hole into it. DO NOT HOLD THE CAP WITH YOUR HANDS WHILE DRILLING. At a minimum, use pliers. In my case, I drilled it out with a quarter inch drill bit and reamed it out further. It isn't terribly critical that it be super exactly centered and a huge hole, but try to be decent about it. Standard warnings - use the proper tools, use safety glasses, lock down the part (semi-gently) in a vise before drilling. The plastic can get hot when drilling.