T3D Re: Toe-In?

[john bercovitz <bercov@xxxxxxxxxxx>]

In our club, Barrie Bieler uses a tilt table to do mineral specimens.
I'm sure the stereo is bulged out but since we don't know what the
specimens looked like in the first place, we're none the wiser.

Dr. T, I understood everything you said except the following.  Could 
you illustrate with an example?  I haven't done anything in that 
range and am having trouble imagining what the problem is.  Thanks

> Second, at high magnifications toeing-in becomes necessary.  That's 
> because the translation required to produce a certain amount of 
> parallax (or on-film-deviation) is such that the field of view can 
> be totally different between the L and R pairs.  It is common practice 
> to rotate the object between shots instead of toeing-in the cameras.

For a proper explanation of the problem which toe-in causes, read
Andrew Woods' paper:

http://info.curtin.edu.au:8080/~iwoodsa/spie93pa.html

If math confounds you, I'm afraid so will Andrew's explanation.  
However, you can always look at the pictures.  If math does not 
confound you, you can enjoy Andrew's program, "3D-MAP", which you
can download from 

http://info.curtin.edu.au:8080/~iwoodsa/

Don't "forget" to register!

John B


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