T3D Re: 30:1

[boris@xxxxxxxxxxxx (Boris Starosta)]

>From: "John Goodman" <jgood@xxxxxxxx>
...
>If translation is not effective, what's the drawback of tilt or
>rotation? A friend says his archeological artifact stereo

As rotation of subject is equivalent to translation of camera (stereobase)
+ toe-in of camera(s), the drawback will be a keystone distortion
(perspective mismatch) between the two images.  I am familiar with this
because my primary method of shooting involves a toe in of two cameras: for
subjects as close as 30 inches (about 75cm) and a stereobase of 75mm, I toe
in about 5 degrees.

The ratio for this type of shot, you will notice, is about 1:10.  I've been
a pretty vocal critic of the 1:30 rule on this forum and in P3D.

>microphotography is very effective, where the camera is
>fixed and the objects are rotated by 6 degrees between
>shots. I imagine that the background is neutral and not a

So here, depending on size and distance of object, I wouldn't be surprised
if your effective "ratio" is about 1:10, also.  (Does this ratio have a
name?  I know it's the 1:30 rule... but what is the "name" of the ratio
1:30, if any?  Stereobase ratio?)

Boris

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



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End of TECH-3D Digest 494
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