Re: [Leica] mxsmanic and pinholes

["Daniel Post" <dpost@triad.rr.com>]

Re your chromatic abberations- take a look at Huyghen's work- while slightly
bereft of mathematical background, he did describe his experiments with a
'pinhole' and how the action of diffraction around the edge of an object can
cause a color fringing becasue of the differing amount of diffraction of
different colors of light.... Boy, this physics stuff is neat, but I think
the dog ate my sliderule, so I can only be accurate to two significant
figures!!!
Dan
- ----- Original Message -----
From: "Mxsmanic" <mxsmanic@hotmail.com>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Thursday, August 02, 2001 8:13 AM
Subject: Re: [Leica] mxsmanic and pinholes


> Malcolm writes:
>
> > I know that it is a relatively minor disadvantage,
> > but aren't pinholes just a little bit restricted
> > by their inability to focus rays of light?
>
> No.  Everything seen through a pinhole is always in focus, no matter where
the
> image plane resides, and no matter what it's shape or orientation.  In
fact,
> with a curved film plane, you can eliminate fall-off on the edges of the
frame.
> By moving the film plane in other ways, you can change perspective.  None
of
> this requires any change in the pinhole, which provides a focused image
under
> all conditions.
>
> I have read that pinholes do exhibit some chromatic aberration, but I
haven't
> found out the mechanism of that thus far.
>