What's your macro philosophy?

[P3D John Bercovitz <bercov@xxxxxxxxxxx>]

So what's your macro philosophy?  I was thinking of taking some
slide bar macro/tabletops (1' to 2' distance) but first I have to 
ruminate, as usual (that's the fun part, aside from looking at the 
results).  I could use the Spicer-Bercovitz maofd formula and take 
viewable macros from fairly close up using a 65 mm stereobase.  
Although this would be realistic, I don't think it would look so hot 
because when you mount them, you'd probably mount to the window and 
a standard window is 7' away.  It's far enough away that I think the 
vergence clue would intrude and tell you it ain't so.  Of course you
could also mount to infinity but then the objects would be floating 
a foot or two away, right in front of your eyes, and the stereowindow 
would be way back there, providing the greatest disparity in the scene.

It seems to me this is another argument for using reduced stereobase.
If you use a reduced stereobase, you increase all three dimensions
by the ratio of normal/used (that's 65 mm divided by whatever base
you actually used).  So if a macro is shot at a foot distance with
a 1/7th (65/7=9.3) stereobase, the near point will be at 7' which 
matches the nominal Realist near point.  Ought to work out well but of
course the reconstructed image will be 7X size.  That's not entirely
bad, of course, but it's not entirely realistic either.  8-)

An alternative would be to mask off the outer portions of a wide 
format mount (say an 8P RBT).  That would help with the vergence 
and window distance if the vergence control on the projector is left 
at its normal setting.  Unfortunately, this is an excellent formula 
for ghosting and besides, who wants the objects _and_ the danged window 
floating in space a foot or two from his/her eyes?

There would be yet another problem for people who still have some 
accommodation and that is that focus distance to the objects is way off.  
I don't think this is too serious, though.

John B

For further info or a refresher on maofd,
  The paper describing it is at:
http://werple.net.au/~kiewavly/bases.html
  The excel spreadsheet is at:
ftp://bobcat.tamu-commerce.edu/pub/photo/photo-3d/technical/maofd/


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