Re: IR and pinhole

[George L Smyth <GLSmyth@xxxxxxx>]

Robert Long wrote:
> 
> 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.

People who work with pinhole are seldom concerned with identifying
"sharpness" with "picture quality."  Diffraction is greater in the IR
spectrum than it is in the visible spectrum, but this merely gives one
more tool to work with.  To see examples of what I am talking about,
please visit the Southwest Wing of my Web page.

george

- -- 
 Handmade Photographic Images     
  http://www2.ari.net/glsmyth/
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