pinholes

[Thomas Knoles <tgk@mwa.org>]

I'm catching up on the email from the long fourth of July weekend, and just
wanted to add a bit to Fred Ward's recent post about the Japanese pinhole for 
M Leicas.

I keep thinking I'd like to try some 35mm pinhole photos sometime, and was
interested to see that Eric Renner's book _Pinhole Photography_ lists a man in
Italy who sells pinholes for Leicas among the other vendors of ready-made
pinholes.  I don't know how his pinholes compare, in price or quality, to those
described in _Popular Photography._  My understanding is that for maximum
resolution, pinholes should be 1) as perfectly round as possible; 2) in as thin
a material as possible; and 3) of the optimum diameter with respect to "focal"
length (i.e. distance of the pinhole from the film plane).  Renner's book has
charts giving optimum diameter and effective aperture for various focal 
lengths.  Thus while a pinhole in a body cap will produce a picture, it 
probably won't be very sharp, if for no other reason than the thickness of the
cap, made even thicker by the material melted by making the hole.  A better
low-tech solution might be to cut a fairly large hole in a body cap and tape a
very thin sheet of metal (brass shim, for example) with a pinhole of the 
proper size over the hole in the cap.
   
I was thinking that when I tried this, I would use my Nikon and drill the hole
in a generic Nikon body cap--it would be cheaper, and besides, I'm not sure I 
could bring myself to destroy anything made by Leica. <g>  Of course one could 
make a wider-angle picture with a Leica, because the hole could be closer to 
the film plane.  I'm not sure why, but it all somehow seems more appealing 
with a Leica anyway. 

Maybe the folks at Leica will produce one sometime--the Pinnitar, Pinnacron, or
even Pinnilux? <g> I wonder how German and Japanese pinholes would compare with
each other in terms of contrast, color saturation, etc.??

Tom Knoles
tgk@mwa.org