[MF3D.FORUM:1651] Re: Viewing 6x7 Gepe mounts

[Paul Talbot <ptww@xxxxxxxxx>]

re: John "begs to differ" and cites Holmes card viewing
in a stereoscope.  John's example does not contradict my
statement, in fact it reinforces what I wrote:

> it would have to be something other than a
> parallel view design (e.g., mirrors or prismatics.)

Holmes stereoscopes use a prismatic lens design, so we
are in agreement so far.  Holmes format cards, however,
are viewed from much farther away than are MF 3D slides.

John again:

> I have a home-made viewer with 50mm dia by 150 mm fl
> achromats...I can view [pairs spaced at] 95mm

Essentially another example of prismatic design, as John
suggests when he states:

> now the arguments regarding prismatic distortion and
> "keystoning" may ensue...

Seems to me we're still in agreement.  ^_^

While we seem to agree on the above, I'm curious about
something else.  Why would you go to the trouble of
shooting MF stereo chromes and then only view with 150mm
FL lenses?  On top of the distortions you mention, that
doesn't sound very immersive.  Your slides probably look
totally free of grain, however!

Paul Talbot