Re: My 7p Realist!!!

[P3D <PTWW@xxxxxxx>]

Dennis wrote about choice of lens focal length on 7-perf stereo cameras:

> If you measure the diagonal of the 7-perf frame, it's exactly 37mm-thus
> it's the "normal" length. Like a 50 or 52mm lens on a 35mm SLR.

Oh no, geometry!  I haven't done that in over 20 years either!  But
somehow these numbers seem a little off.  7-perf has a 37mm diagonal,
but 8-perf has a 50 to 52 mm diagonal?  Isn't 8-perf closer to 42mm
on the diagonal?  I had heard a long time ago that the so-called
"normal" 50mm lens on a 35mm format camera is actually slightly
telephoto.  Am I remembering something incorrectly?

The geometrically challenged Paul Talbot


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