Archived posting to the Leica Users Group, 2001/04/06
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> Let's see. Now that there are threads on the Noctilux and pinhole lenses
> going in parallel, all you engineers:
>
> What would the diameter of a 30mm focal length pinhole lens have to be if it
> were f=1?
>
> 1/30 of a millimeter? Anybody have a slide rule handy?
Why slide rule? It should have a 30 mm diameter.
Guess what? If you have a SM Leica, you already
have a f/0.6 28mm lens! Just unscrew your Elmar
or Summitar from front....
:-)
Pinholes works because of diffraction. And works
at the border between unsharpness caused by too
big diameter of pinhole and beginning of diffraction
effects being too visible and degrading image.
This border for 35mm film starts somewhere about
f/100 up to f/300...
- -----
St.
(Stanislaw B.A. Stawowy)
http://www.geocities.com/Stanislaw_Stawowy
Echelon/Carnivore lines: Bob Black, Hakim Bey,
Ralph Klein, Sabotage in the American Workplace