The Lex 35 is a $1.50 trashcam available from American Science Surplus. The following is a cross-post from the Free Camera group:
If you want to get inside the mighty Lex 35, here's what you do:
First, open the back door. There are now three screws to unscrew with a tiny phillips (or similar) screwdriver. Look here:
The one in the hole above the hinge on the door is the surprise, and it will take a narrow screwdriver blade to get at.
Now gently pull the front from the back, top first (freeing the shutter release from the front cover first). Or you may have to pry gently on the bottom edge first, and bend the cover so it's free of the rewind button. Careful! Don't lose any of the parts that may come out - the door latch, and a little spring holding the shutter release up both may come out.
To get at the shutter, remove the lens board. It's held on by two more tiny screws:
The lensboard also holds the shutter-release arm in place, so when you put the lens back on, you'll have to make sure the shutter-release arm is where it's supposed to be.
Here's the shutter itself:
It appears that the Lex 35 has about a 35mm focal length and an aperture of about f/11. Assuming a fairly blurry image, they've probably designed this to focus at about 8 feet and be acceptable from 4 feet to infinity.
That means we could drill out the aperture to, say, f/8 and it will focus from 5 to 27 feet. Or mask the aperture to f/16 and it will focus down to 3 feet.
It'd be interesting to put a time-exposure shutter on the Lex, too. I'm considering doing that by drilling a hole in the bottom and putting a pushpin in such that it holds the horizontal shutter-release arm partway open after you press the shutter. If you have a more elegant solution, let me know.
I've now drilled out the aperture to f/8 and done the pushpin thing. I'll let you know how it goes.
9:52PM, 15 February 2006 PDT