advancing film - bigger spaces between frames

[John Koehrer]

To change the spacing on a mechanical camera you're going to have to find someone who has the capability of manufacturing new gears for your camera.
Probably be less expensive to get a different body with the same lens mount.

The optoelectronics used to track film in most of the autoadvance camera simply counts sprocket holes.

[Murray@uptowngallery]

Ha!

What you need is a cruder camera (one example given earlier).
Like an Argus C3, where you can unlock the winder and tweak it a little further after it stops, similar on a Kodak 35 or 35RF and most 120/620 folders.

I ran some 220 in a 120 camera and hand counted turns...and got increasing borders because the spool diameter builds up and winds more film for each turn.