P3D Re: Cardboarding

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Boris Starosta <boris@xxxxxxxxxxxx>


>For your consideration, I submit Ron Labbe's photo of Leah
>(http://www.studio3d.com/pages2/people.html), which he has stated (to me in
>a private communication) was taken with a telephoto (I can't recall the
>f.l., but it was quite a bit over 80mm).

The caption on the site in question says that base-to-base SLRs with 135mm
lenses were used.  Base-to-base SLRs will generally have a slightly
wider-than-normal stereobase, but not excessively so (like, say, side-to-side
SLRs).

>On the website, cross-viewing,
>the depth looks exaggerated (stretch), which implies to me, given the use
>of a telephoto, that the stereobase was not normal (>>70mm).  Ron, feel
>free to jump in on this.  I've not seen the slide, nor have I met Leah in
>person, so I cannot fully judge the image, but on the web it looks very
>strange to me.  I propose this is an example of the use of a larger
>stereobase to compensate for a longer taking lens f.l.


Remember the recent discussion about ortho and viewing distances?  I do. :-)
I can make this image squash OR stretch, depending on where I view it from.

(One problem, for me, is that it is a human face, and I have a lot of trouble
seeing z-axis distortions in faces.)

     -Greg W. (gjw@xxxxxxxxxx)



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