P3D Re: 43mm Pentax lens

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>>The 43mm FL is also nearly ortho for Red Button
>and similar viewers (John B would love it :)
>
>Does that mean that most vintage stereo camera lenses (with focal
>lengths of 35 - 37mm) don't produce 'ortho' images when viewed in the
>Realist (or similar) viewer?

  Yup. The RB produces about 26% stretch (44/35) on
shots taken with a 35mm lens. Some people actually
have preferred this "accentuated" depth in my Realist
slides in RB vs nearly ortho medium format shots
(82mm viewing lens, 80 or 75mm camera).

  The viewers that have the 47mm FL lenses (Wollensak?)
give 34% stretch with slides taken with 35mm lenses
and the $4-ish Radex viewer that Reel 3-D sells (50-ish
mm lenses) has 42% stretch for this case.

  David White did produce a viewer that was nearly
ortho, using 3 element lenses AFAIR but George T. or
someone reported the lenses aren't great (edge sharpness
or coverage?) in spite of the lack of stretch.

Greg E.


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