P3D RE: Filters and 3D

["Ivester, Paul" <ivestep@xxxxxxxxxxx>]

Bob Maxey asks about use of polarizers for stereo photography. 

What I have done is mount a pair of ordinary 49 mm polarizers 
onto a rectangle of black plastic (Kydex (ABS), .125 in. thick) 
with round holes the right size.  It was necessary to glue 
these in, as I was unable to thread the inside of the holes 
(my tap and die set did not come with a 49 mm tap!).  I then 
attached an identical rectangle to the back, with a pair of 
holes slightly larger than my lens diameter.  I sprayed the 
surface of this that was toward the back of the filters with 
ultra flat black paint to reduce reflection, though flocking 
would be better yet.  I made marks on the filter rings 
indicating their angle of polarization, and marked a set of 
lines at equal angles around the perimeter on the plastic 
board.  

In use, I sight through the polarizers and adjust them by eye 
for the desired effect.  Then I check the angle marks to 
ensure that they are identical.  I slip the unit over the 
lenses, and snap the photo (after compensating for the 2 
f-stop loss).  I have had quite pleasing results.  At one 
time, I had 2 polarizers from different manufacturers.  
They were sufficiently different that the results were poor.  
It is therefore important to have matched polarizers.  This 
system works well on cameras that have the viewfinder at the 
top of the housing.  I would be a problem on the Realist and 
Kodak (start saving up for the Rochewhite polarizer 
attachment!).  I suppose one could use an auxiliary 
viewfinder in the hotshoe to overcome this.

Paul Ivester
mailto:ivestep@xxxxxxxxxxx



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