P3D 25.4 for stereo BASE

[sd3dnorm@xxxxxxxxx (Norm Henkels)]

I'm dizzy from all the various formulae (math) recently posted for the
ideal stereo BASE. All are near, very near a rule of thumb passed on to
me by the late Walter Heyderhoff, a 6 star PSA Stereo exhibitor. The
beauty is in its simplicity in implementation. No adding, subtracting,
multiplying nor division. Simply measure the subject DISTANCE (pick
one....from the front of the front element, from the middle [nodal
point?] of the lens or the film plane) in INCHES. Use the same number
(numerical value) in MILLIMETERS as the dimension for the lateral shift
of the camera for a sequential stereo pair. I might add "of an inanimate
subject/object" Any movement in the scene (between exposures) will spoil
the stereo.

Why 25.4? Because it's the conversion factor for millimeters to inches.
25.4 mm.= 1 inch. Sure, 1/25.4 is slightly less than the often stated
1/30 rule but infinitely easier to apply in the heat of a shoot, without
a calculator. Good number to remember, too.

Norm Henkels

                        
                                    




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