Question on image circle and medium format pinhole camera design

I just got back my first roll of film and 5x5 proofs taken with a converted
1953 Dacora Digna 6x6 slr camera. I removed the retractable lens assembly
and installed the .0087 pinhole from the pinhole set I bought from Pinhole
Resource. The focal length of this camera is approximately 36mm, so it's
wide angle.

I'm thrilled with the results! The proofs are properly exposed (surprise
given I was using a flap for the shutter and counting the seconds) on Ilford
XP2 film (iso 400). I used f64 as the base exposure reading, then multiplied
by 6.3, which worked great.

Question: my images are all circular, cutting off the corners cleanly of
the square print. Is this because the image circle is too small for the
film? I'm wondering if the circular edge of the front plate is being picked
up on film, since the edge sticks up about 1/4 inch.

Any help appreciated,

R.J.
Received on Tue Nov 12 14:43:04 2002