T3D Re: 1.2mm OFD theory

[erker@xxxxxxxxxxxxxx (Greg Erker)]

>Earlier we were presented an example where it required to use a
>3.6 inch stereo base to get 1.2 mm OFD.  Then we read that you
>might still want to use 2.5 inch base but move the background
>a bit further, so you can still get 1.2 mm OFD.  Seems to me
>that the 1.2 mm target has become an obsession.  So maybe the
>desire for constant "infinity" separation is fueling this.

  Perhaps. That is why I raised the theory.

>But with a close-up and macro, there is no real infinity.
>One could even say that 2.5" separation of the distant points
>on the screen is unatural for a close up.

  I don't have any projection equipment so
all my experience is with viewers. In 35mm
and medium format I always (try to) mount
to the window.

  When I get a new roll of Realist shots
back from developing I usually quickly
cut them up and stick them in albion mounts
with the film chips roughly the correct
distance apart.

  Later when doing the final mounting
I find many slides improve a lot when
the film chips are tweaked to bring the
near object up to the window.

---

  I know that constant infinity separation
is very important to some people in projection.
Perhaps my lack of projection experience is
why I use the mount to the window method.
(I know some people prefer mount to the window
for projection too.)

Greg E.



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