wrote in message
ups.com...

I recently purchased an early Technika IV (s/n 63089) [...]

I'm sure Bob Solomon (HP Marketing) can help with the serial numbers and
age.

I noticed that
with my longest lens (210 mm) the corners of the image were getting
rounded off on the negative.

Which 210mm lens? How much rounding (vignetting)?

So, my questions. Are these rounded corners on all Technika IV's? The
back on this one looks unmodified, so I assume it's as originally
manufactured. And what do people do about this problem (other than just
accepting it)? It looks like it would be very difficult to file the
rounded corners out without removing the bellows first -

I'm baffled by your observations. The 'roundness' seen from the film side is
due to the rotating back track. If you remove those corners it won't obviate
vignetting, but it will destroy the back. Regardless, the exposed area of
the film in the holder is not effected.

and the
bellows appear to be glued on, so I'm reluctant to attempt that.

Don't go there.