The Un-Round & Multi-hole
We can be MUCH more "playful" than scientists.
Imagination and willingness to try new things are essential here.
Some general rules:
- round is the "sharpest"
possible pinhole under normal conditions
- any deviation from round will
affect the sharpness and the "feel" of the image.
example: an oval or short slit will smear the image in the direction of the
longest dimension of the hole.
- points of light in the image will
take on the shape of the pinhole.
examples: a ring shaped hole will
produce ring shaped halos in parts of the image. A star shaped hole will produce
star shaped halos.
MULTI - HOLE
- each pinhole will cast its own
image onto the film plane
- the range or width of the image
produced is determined by
- the angle from the perpendicular
this may not be obvious. Looked
at head-on, a perfect pinhole looks round, but as you get further and
further away from head-on, the hole looks more and more oval until it
disappears. The thicker the material the faster this will occur, but
even an infinitely thin material disappears at 90° (edge on). And the
smaller the hole, the less light gets through and the lighter will be
the image on the film plane. Note the 'hole' is also no longer round. As per above explanation of the unround hole, the image becomes distorted. This effect is most pronounced in extreme wide angle images.
- the chamber shape designed
into the camera
So in practical terms
this means there is a "fall off" in the image away from the center.
- the closer pinholes are to each
other the more likely there will be overlap in the images unless there is
something structural to prevent this from happening. Pinholes are VERY wide
angle. So, even on a 4x5 with a 33mm focal length pinhole, almost the entire
frame will be covered.
This gives us two possibilities:
- overlapping images, or double
exposures from different angles to the subject
- side by side images with different
angles to the subject
From this we can add intentionally,
a third possibility. Time. One pinhole need not be used at the same time
as another, hmm……
(the separated pinholes would produce
a stereo pair, hmm, 3D pinhole)
Part of the magic of pinhole is the
infinite number of possibilities, but don’t forget the aesthetic side! Good
subjects and composition are still the best images. We should not depend on
This is an example of the extreme
in multihole cameras. 32 ideal pinholes of about 12mm focal length onto 4x5