Re: Pinhole 9x12cm quest

Larry Bullis (lbullis@ctc.ctc.edu)
Mon, 13 Oct 1997 11:25:06 -0700 (PDT)

On Mon, 13 Oct 1997, Richard Sullivan wrote:

> And 2 more cents worth.
> >From the classical literature I gather what is wanted is really a pinhole
> and not a pin tunnel. To exaggerate: if one had a piece of 5 mil stock and
> drilled a hole through it, one would have two diffraction edges to form
> images, the entry edge and the exit edge. This is why the art of making a

This is true. I've taken this up with Eric but he thinks that the laser
holes are good enough for normal uses; ie, with more or less conventional
hole to film distances and not the extreme crazy wide angle that I
typically am using. He is probably right. The best holes have a knife
edge all the way around and are blackened to prevent reflections (which
tubular holes have a lot of). And blackened not with ink or paint which
clogs them up and makes messy junky edges, but with something which
blackens each molecule (ie, toner).

The role of diffraction in your message is unclear. I'd really like to
hear how people think a pinhole image is actually formed.

BTW Tom, not to worry, I'm not mad.