Quote Originally Posted by RalphLambrecht View Post
You correctly referred to the angle of view, which is calculated from the negative-format diagonal and the focal length, but we need to make sure that we are not confusing it with the 'actual' angle of view, which is highly dependent on the thickness of the pinhole material and responsible for the image circle? (see attachment)
I would agree with you that DWThomas correctly describes 'angle of view' as a product of film size and pinhole-to-film distance.

I think it's misleading and confusing to also call the restriction of the light path by the thickness of the pinhole material the 'angle of view'. Why use the same term for two entirely different effects? In my view the effect of the pinhole material thickness would much more accurately be described as 'angle of coverage' if we're choosing terms analogous to lenses.

Lee