[MF3D.FORUM:32] Apparent image size, MF verus

[Paul Talbot <ptww@xxxxxxxxx>]

When I first saw MF stereo images, I wanted to quantify the
apparent image size difference between MF and Realist format
images.  I bounced a couple things off John B off-list, but
never really reached a firm conclusion.  Now someone else is
looking for my help in going down that road, and I still don't
have a definite answer.  :-(

Here is something I just dreamed up.  I'm intereseted in any
comments as to the validity, or lack thereof, of this approach.

Format   Size     Viewer FL    Mag Factor        Apparent size
------   ----     ---------    ----------        -------------
MF       50 x 50  80 mm        3.125 (250/80)    156.25 x 156.25
Realist  23 x 21  44 mm        5.68  (250/44)    130.68 x 119.32
35-FF:   23 x 33  44 mm        5.68  (250/44)    130.68 x 187.50

If this is true, then 35mm full frame images have a significantly
wider (20%) field of view than do medium format images mounted
in the 50 x 50 mounts.  (Note, I understand the other advantages
of MF like much less visible grain; at the momemt we are just
talking about apparent image size.)

I seem to remember John B saying angles had to be factored
in, not just height, width, or area....but of course it was
all way over my head.  ;-)

Thoughts?

Paul Talbot