Re: 1 to 30 rule

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Wed, 9 Jul 1997 10:22:07 -0500
>From: P3D gecko  <gecko@xxxxxxxxxx>
>Subject: 1 to 30 rule

>I am trying to take a stereo photo of a city-scape, and for the first
>time I'm going to use the 1 to 30 rule for determining the stereo base.
>To use the 1 to 30 rule, I have to know the distance to the subject.
>Does anyone know how to determine the distance of far objects.  I've
>thought about buying a spotting scope, though I do not wish to spend
>more than $100.00 to determine the distance.  Any suggestions?
>Also, is there a 'special' rule for doing hyperstereos?

However you do it, I strongly recommend that you take a number of shots
at a variety of spacings, and pick out one or more pairs that you like.
It is unlikely that the most pleasing spacing for a particular situation
will be exactly 1:30 - for very long distances, I tend to find that a smaller
interocular than the 1:30 rule calls for usually makes a more viewable pair.

If I have no other means of estimating the distance, sometimes I start with
the minimum interocular that produces a perceptible change, then bracket
around that.

examples of multishot technique:
1---2---3---4--...
1---2---3-------4---...
1---2-------3---------------4---....

John R


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