Re: What is Diffraction?

From: Guillermo <penate_at_domain.name.suppressed>
Date: Sat 14 Dec 2002 - 00:09:07 PST

----- Original Message -----
From: "Lisa Reddig" <lisa@julianrichards.com>

I thought I had commented on this Lisa's post, but I guess I didn't, here is
my admitely late comment:

> So what everyone is basically saying is that the reason my pinhole images
> are not precisely sharp is because it is in actuality impossible. Even
with
> all the equations and formulas. Correct?

As we all know pinhole is not about sharpness, nor I am suggesting we strive
for it. Having said that, it is actually possible to make poinhole images
that under certain conditions could be undistinguishable from glass lens
images. A good example is an image in the Renner's pinhole book. Under the
assumption that we humans can discern more than 5 line pairs per millimeter,
most of the 35mm format lenses (especially the Zoom variety) would be hard
pressed to produce enough resolution on film to give those 5 lp/mm when
enlarged 8 times for a print about 8x10" in size. The same 5 lp/mm could be
achieved if you make an 8x10" pinhole camera with a 120mm focal length or
under, using the so called optimum pinhole size. Print should be viewed
with unaided eyes.

Guillermo
Received on Fri Dec 13 20:26:11 2002

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