P3D math-less depth charts

[tmd@xxxxxxxxxxx]

Dick said:
Tom said:
>>This slide had too much depth.  I've designed a simple tool to
>>help me avoid this situation in the future.  You can see it at:
>
>> http://www.deering.org/curves.html
>
>These interesting tables seem to restate graphically the Charles Piper
>Theorum (as I call it) that permissable depth for a Realist-format
>camera stereogram may be calculated simply using the standard depth of
>field scale on the camera, using f/5.6 in the case of the Realist.  I
>have compared several combinations using the Kodak Pocket Photoguide
>Depth-of-Field Computer, and the correlation appears to hold for all
>possible combinations.

All possible combinations?  Simply untrue.  For instance, with a near point
of three feet, the f5.6 guess says the "permissable depth" is 12 inches
deep, where the curve says 26 inches.  Since when does 26 inches equal a
foot?

Or to put it another way, the rudimentary f5.6 guess would give you 0.67mm
of film deviation, nowhere near 1.2mm.

The curves give mathless access to accurate geometry.  Accent on "accurate.
It's okay if you don't want to use them, but don't discourage others from
wanting to be a bit more precise.


Tom



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End of PHOTO-3D Digest 2962
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