Re: Holga pinhole?

David Jacobson (jacobson@cello.hpl.hp.com)
6 Apr 1997 09:05:51 -0700

In article <199704051256104552758@max31104.rmi.net>,
Clyde Soles <csoles@rmi.net> wrote:
>Anyone know the optimal size for the pinhole on a converted Holga (and
>what the f/number works out too)? The hole-to-film plane distance is
>about 53 mm. TIA

The optimum size for pinholes is discussed in the lens FAQ, which can
be accessed via the URL
ftp://butler.hpl.hp.com/jacobson/photo/lensFAQ.

Q37: What is the optimum aperture for a pinhole camera?

A. d = .036 sqrt(Si), where d is the diameter of the pinhole in
millimeters and Si is the distance from the pinhole to the film in
millimeters.

The optimum aperture for a pinhole camera depends on what criteria is
used. The formula given maximizes the spatial frequency at which the
MTF for 555nm light will be 20%.

-- David Jacobson