P3D Last comment on stereo base

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Here is why I do not use the formulas:

On the stereo base discussion, one question that is not brought up 
clearly is the objective of the various formulas, rules of thumb
and spreasheets.  What is the 1/30 rule trying to achieve?  And
what will happen if one deviates from this (or other) rules?

This rule is trying to limit or optimize the stereo deviation.
The two pictures in a stereo pair look very similar but are not
identical.  There are deviations which are responsible for the
sense of depth.  Too much deviation will produce a pair with "too
much depth" which is difficult to view (especially in projection) 
while no deviation will produce a pair with no depth.

Here is my problem with the formulas:

They are just suggestions.  They do not take into account things
like the subject matter (not metrics of the subject, but the subject
itself), personal taste, etc.

Here is one extreme example:  There is a celebrated pair (husband
and wife) in PSA who shoot flowers with "soft focus" (usually
vaseline on a filter).  I have seen their entries in PSA salons
and have borrowed their instructive slide set (available via PSA
and highly recommended).  These people use very small stereo base.
I swear that some of their stereo pairs are totally flat (identical
picture in right and left).  Sometimes, ON PURPOSE, they mount the 
pair pseudoscopically (what do we have here?  negative stereo base???)
Whatever little depth there is, it is reversed.  I have seen one of 
these slides win top awards in PSA.

So, the hell with the formulas!!!!

George Themelis


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