Hello, I hope you can help me with the issue of creating an aperture-scale for my 90mm f8 Super-Angulon which I have mounted into a Prontor-S shutter (copal-0).
I think I know the math for calculating the aperture size, but I am puzzled as to where to do this measurement. As a comparison I am looking at my 90mm f6.8 Angulon.
At first I thought I would just make the aperture holes within the shutters the same size using the Angulon as a reference, easily done.
Some people on this forum claim that the aperture (aparent?) is determined by looking through the front cell of the lens since the lens has a magnification factor.
So when I then mount the front cells into the respective shutters to view the 'aparent aperture' they differ quite a bit...the SA opening seems much smaller.
(It's also interesting that the 'endpoints' (rear lens element) of the front cells of the two lenses differ so much too, with the f6.8 being much smaller than the f8 SA being almost the size of an f5.6 aperture??
Please, what's the trick here?
(Or even better perhaps...does anyone know the shutter aperture hole sizes for f8-f32 for the 90mm f8 Super-Angulon?)