Back in the day I had a stereoscope with a stereogram. The effect was fascinating.
These days I have a few rolls of cheap, expired slide film and a film camera with a 50mm and a 100mm lens.
If I were to build a jig for my tripod so that it allowed me to take stereograms, how big should it be? I imagine some very basic horizontal bar that allows the camera to be mounted either left or right from the center. How far should these two positions for the camera(s) be apart to get a good effect? How does it change depending on the focal length?
Let's assume scenes without too much change in them, so that using a single camera could work.
I'm looking for a concrete distance as I do not want to shoot through an entire roll of film before knowing what's going on.
Let's say the focal length is 50mm or 100mm, the subject is 1, 5 or 10m away. What should I choose as a distance in these scenarios?