P3D RE: 65mm versus 75mm stereo base

["David W. Kesner" <drdave@xxxxxxxxxxxxxxxxxx>]

In photo-3d digest 2968 Dana Archer asks about the difference in the 
RBT stereo bases. Dr. T mentioned that there are other factors 
involved and he is right.

The RBT X3 actually comes in three models: the model A has a 65mm 
base and produces 20 pairs of 24x33mm, the model B has a 75mm base 
and produces 18 pairs of 24x36mm, and the model C has a 65mm base and 
produces 13 pairs of 24x36mm.

I chose the model A for several reasons. First I believe I can 
perceive a slight hyper appearence of the 75mm base (65mm is closer 
to my actual interoccular distance). Like Dr. T I also like to shoot 
a lot of "semi-closeups" and the 65mm base works much better and you 
don't have to crop as much to get a proper window.  I did not want to 
give up seven pairs from every roll just to get full frame chips so 
the model C was out. Besides I like to use commonly available 
equipment to view and project my slides. That means Red Button 
viewers and TDC projectors and not Pin Sharp viewers and dual 
carousel projectors. I also like the ability to use the stereo 
viewfinders on the model A. I cannot see through both viewfinders in 
the model B. This will be especially nice when I get the macro 
attachment.

One last thing - even though the Model A is meant to be mounted in 
the RBTW mask which is 23x31.5mm I like to use the standard 7p or 
European mask which is 23x28mm. Once again this is because most 
viewers and projectors won't show the extra 3.5mm of the RBTW. Also I 
like the extra freedom I get in mounting the window in the 7p.

I hope this helps you decide. If you have any more questions, just 
ask.

Thanks for the time,


David W. Kesner
Boise, Idaho, USA
drdave@xxxxxxxxxx


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