Chuck Norcutt wrote:
> Complete with Lord Rayleigh's formula for optimal pinhole size.
> <http://en.wikipedia.org/wiki/Pinhole_camera>
>
I'm aware of the formula. However, Zero Image doesn't follow it:
Pinhole diameter
Model Format FL mm Camera Rayleigh
135 35 mm 25 0.18 0.22
2000 6x6 25 0.18 0.22
69 6x4.5 - 6x9 40 0.18 0.28
612 6x4.5 - 6x12 40 0.25 0.28
Given Zero Image's relative success and longevity, their endless
statements on their site about fanatical testing and QA, and Bill's
statement that they are particularly sharp, I assume their pinhole sizes
are based on empirical testing with the actual pinhole material
thickness, material and pinhole sizes.
According to "Pinhole Photography", by Eric Renner, it appears that
Rayleigh's formula was empirically derived from experimentation.
Although E. Lommel had done the first calculation of diffraction through
a round aperture in a paper in 1885, it was not well known when Rayleigh
came up with his almost identical formula in 1891. There are also other
formulas in use. <http://photo.net/pinhole/pinhole>
So, I wasn't looking for theory, but info on practical results. BTW, the
downside of Zero's smaller apertures is slower f-stops and longer exposures.
Moose
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