P3D Re: Differential Focus

["Ray Moxom" <raymoxom@xxxxxxxxxx>]

In response to my posting on one of the top exhibition stereo photographers
using Differential Focus to optimise film speed, shutter speed & DOF for
many of his action shots - Dr T has asked the following questions in
P3D-3250.

Q1) who is this top exhibitor (I suspect Allan Griffin),
Q2) how exactly does he use differential focusing,
Q3) how do you know about it (personal communication or is there
something published somewhere?),
Q4) expand on this "optimize film speed, shutter speed & DOF", if
possible,
Q5) are the results of differential focusing impressive or the overall
technique of action stereo with twin rigs that has won the awards?
(I suspect the later)

A1) you suspect correct;
A2) slight focus differences to ensure that all elements of the picture are
in sharp focus in one or the other chips;
A3) presentations and personal discussion - this is not new and it may also
have been published in one of our club bulletins and/or in Stereoscopy, I
need to check this out;
A4) exactly that - optimise the combination that gives the best result;
A5) The results are impressive - this is just one of Allanís many techniques
that often gives him the edge on this type of shot.

Ray




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