Re: Beginner's question answered

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Mon, 9 Jun 1997 18:06:26 -0500
>From: P3D Brian Reynolds  <reynolds@xxxxxxxxx>
>Subject: Re: Beginner's question answered

>The twin bar and the slide bar make it surprisingly easy (at least to
>me) achive results.  Not necessarily good results, :) but I can see a
>stereo effect.

A slight caution which doesn't necessarily apply to you: sometimes when a
person getting into 3D views a reversed (pseudoscopic) stereo image, they
make that exact same comment. At one point when I was a teenager and had
no exposure to 3D other than Viewmasters, I would take a stereo pair of
prints, dutifully place the left view on the left and the right view on the
right, then *cross view* it. :-)  A way to check for this is to see whether
it looks better when you swap the two views. The next typical pitfall of the
beginner is toeing in the camera(s) to get converging views.
As I mentioned, I have no reason to believe that this caution applies to you,
but it may be useful for some people starting in 3D.

>What I would like information on is:

>6. Antique stereo cameras

>I'm specifically interested in turn of the century (give or take a
>couple of decades) large format stereo cameras (e.g., like the one
>depicted in "Across the Sea of Time").

>What was the focal length used for cameras that were used to create
>stereo cards for Holmes viewers?  I have a 135mm Optar (from a Speed
>Graphic) and was considering getting a second to use in this project.

>What was the image format on the film (or plate)?  I've thought of
>either using on sheet of 4x5 (each iamge would be about 3-3/4"x2-3/8")
>or 5x7 (4-3/4"x3-3/8") or two sheets of 4x5.

The width of the ones I've seen is typically around 3", and the height may be
3.5" or a little higher. For modern Holmes cards, regular glossy 3.5"x5"
prints trimmed to 3" wide (made from 35mm negatives taken through a 50mm lens)
work very well. The trimming is done in the proper relative positions to set
the "stereo window".

Somewhere (Ferwerda's book???) I got the impression that the stereo cards
of the 1800s were usually *contact prints*, made from a negative of the
same size.

John R


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