Re: [photo-3d] Re: Camera separation in stereo photography

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>All of my viewers have adjustable lens separation.You could be right about
>me being in th miniority as that is what appears to be bu still how does one
>explain the trriffic acceptance of your fie woks shot. I beleive that 35 mm
>stereo requires more deviation thanMF because of the greater detail
>available in the MF slides and the considerably less detail of 35mm. As to
>my tripod it is a standard hight eye level, no triks invlved but I do like
>to use filters. Don.

  Okay, so it's not a lens separation problem.

  Regarding my fireworks shot: maybe it's just
a good/great photo, whether it has 1, 2 or 3mm
of OFD.

   You might want more _angular deviation_
on a 35mm slide to compensate for less detail
being recorded. But I doubt you want more
_linear (mm) deviation_ since you view the
35mm slide with about twice the magnification
of MF (thus giving you about twice the angular
deviation for the same linear OFD).

---
  Let's assume your camera lenses are 6 feet
above the (level) ground and the camera is
aimed horizontal (not tilted up nor down).
For 6x6 format you have the following vertical
angles of view:

75mm lens: 41 degrees
60mm lens: 50 degrees
50mm lens: 58 degrees
40mm lens: 70 degrees

  With some trig we can figure out far away
the ground comes into view for the various
camera lenses. The horizontal (along the ground)
and diagonal (from lens to visible point on ground)
are:

75mm: 16', 17'
60mm: 13', 14'
50mm: 11', 12.4'
40mm: 8.6', 10.5'

  If you are set up in a field of 3'
high grass then divide all the numbers by 2
since it's equivalent to having your tripod
3' above ground. 2' grass: multiply by 4/6.
and so on.

  So it seems to me that a person who could
tolerate "normal" (2.7mm in medium format)
amounts of OFD would have no problem viewing
shots taken with any of these 4 lenses (assuming
a normal 2.5" lens separation). Assuming no
grass. 3' tall grass could cause problems
I think.

  But if you can only tolerate half as much
then some of these may be hard to view. In
which case you have to aim the camera upward
a bit or stomp down the grass, or maybe find
the top of a hill or mount to shoot from.

Not mathophobic - Greg E.