Quote Originally Posted by EKDobbs View Post
What exactly is a cell? Is it a piece of glass? What will the focal length be?

a lens cell would be like a plano convex lens, a meniscus lens like in a box camera.
they are very affordable at the surplus shed.

you could have the lens so the curved part is OUT or IN depending on the effect you want.
if you want to stop the lens down, just put your washer/fstop/waterhouse stop infront of your lens
and it will sharpen things up as sharp as you want it. to figure out how big a hole you need to cut for
f32 for example ... you will divide the focal length by 32 and it will give you the diameter of your hole
( check out this video for exact stuff : http://www.youtube.com/watch?v=CIFNdfjem18 )
as erik suggests the focal length could be the length of the camera box, truck bed from where the lens is
to where the exposure plane will be. measure it in mm and poke around on the surplus shed website ...
they have very large lenses ( like 150mm in diameter )

you can make your paper plane move in and out of your camera-body by having it on a rigid frame that
slides in and out of the box, have a big sheet of ground glass, waxed paper, scraped up plastic, window tint
whatever you want to use ... and put your paper inside ontop of the focus screen.

have fun!