Re: IR and pinhole

[boblong@xxxxxxxxxxx (Robert Long)]

On Wed, 28 May 1997 09:29:06 +0300, Hannu Jarventaus wrote:

|Some time ago I made a pinhole camera accessory for my Canon EOS
|system following the instructions in the EOS Magazine. It works well and
|uses the cameras exposure metering, so it is easy to use.
|Pictures are little soft, but that=B4s expected.

The statement that too small an aperture will result in a *loss* in
picture quality with IR film because of diffraction has surfaced here
and elsewhere repeatedly.  Shouldn't pinhole cameras be worst-case in
this respect?

I assume it works like sound: the more nearly the physical dimensions
of the object approach the wavelength being propagated, the more
unruly or problematic the propagation becomes.  Otherwise the tiny
apertures that are said to be inappropriate for IR would also be a
problem with visible light.

Comments, please?  Since I seldom work at less than f/16, I have no
first-hand experience of these phenomena.

Bob Long
(boblong@xxxxxxxxxxx)
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