Quote Originally Posted by Thomas Bertilsson View Post
Heck if I know. There have been many film formats in the days of past, 127, 120, 620, 135, etc.
135 is also called 35mm, and a full frame measures 24 x 36 mm, which also doesn't make sense.
I think 35mm film is actually 35mm wide, measuring edge to edge. Remember the original 'full frame' was for motion picture, which runs the film through vertically, so the frame there wasn't even 24x36mm. Wiki has many more details than this I'm sure.

Have fun with the camera.