T3D Re: TECH-3D digest 505

[boris@xxxxxxxxxxxx (Boris Starosta)]

>From: Dogbreath <hopi@xxxxxxxxxx>
...
>If I'm shooting a flower from, say, 200mm away (macro) with a 35mm SLR
>equippied with a 50mm lens, what adjustment should I make to my stereo base
>(my calculations put it at 4mm) and/or my base when mounting to create the

This is going to be a non technical reply on the tech list.  Sorry about
that.  I do not use any calculations at all, just shoot by the "seat of my
pants."

First of all when shooting with a slide bar, you can always take a series
of three or four exposures, stepping along the rail, giving you a variety
of separations to choose from after processing.  It's educational!

I just started with some mild macrophotography, as you describe it above,
and I pretty much am sticking to my 1/10 rule!  Your four millimeter
stereobase above would not give you much depth, I think, unless the flower
is really big!

Six inches away from your camera (200mm), I say give it about two to three
cm of stereobase.  (I would shoot three exposures.  Imagine your slide rail
has a little mm ruler on it: shoot 1. at 0mm, 2. at 20mm, and 3.at 30mm
along the rail.  This gives you three slides with three possible
stereobases to choose from: 20mm, 10mm, and 30mm.)

I'm assuming a smallish flower - maybe one inch across/deep.

Adherence to the 1/30 rule is the cause of more flat stereos than I care to
think about.  Ruins a lot of potentially really great stereo shots.

Boris

Boris Starosta            boris@xxxxxxxxxxxx
                          http://www.starosta.com
usa 804 979 3930          http://www.starosta.com/3dshowcase



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