Re: My 7p Realist!!!

[P3D emdesher <emdesher@xxxxxxxxxxxxxxxxxxxx>]

On Fri, 10 Jan 1997, P3D wrote:

> 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
> 
> 
You are right-it's slightly long, but the convention is to call it 
"normal".  Dennis 


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