A few years ago, I was interested in doing macrophotography of individual
flowers with an 8"x10" camera. The biggest problem I encountered in using
conventional lenses was very shallow depth of field, even with the smaller
apertures of an iris diaphragm. I considered using a pinhole to get around
this problem, but the main difficulty was the inablility to use the ground
glass for accurate composition.
The solution I came up with was the use of a Waterhouse stop with a very
small aperture to replace the iris diaphragm in a conventional lens. I made
a 1 mm Waterhouse stop using the usual pinhole technique with sewing needles,
sandpaper, etc. as has been recently described on this list. The brass shim
stock was too flimsy to use without some sort of reinforcement; so, I glued
it to a piece of wood veneer 1/28" thick as a support. I painted the entire
structure black.
I used a 135mm Symmar lens, which easily covers 8"x10" when extended out to
300 or 500 mm when used as a macro lens. I composed on the ground glass with
the lens at full aperture. Then, when ready to expose the film I took off
the front half of the lens, put in the 1mm Waterhouse stop, and reassembled
the lens. The functional result was a pinhole camera. The depth of field
was essentially infinite, with an effective aperture of f400 or so. In
addition, just as with a regular pinhole, the sharpness was limited by
diffraction of light as it went through the tiny aperture, so that the image
had the softness and lack of critically sharp focus that is so characteristic
of pinhole cameras.
So, I had the luxury (by pinhole standards) of being able to compose on the
ground glass, yet had the extreme depth of field and soft focus typical of
pinhole work. The characteristic pinhole soft focus combined with the
inherent softness of platinum/palladium prints provided a wonderful effect
with close-up portraits of flowers such as orchids and iris.
Charlie Palmer
Albuquerque NM USA