P3D Re: Cardboarding

[michaelk@xxxxxxxxxxxxxxxxxx (Michael Kersenbrock)]

> To me, cardboarding is the opposite of "stretch".  It is seen in slides (or
> prints) that are being viewed with a viewer that presents a wider field of
> view than the taking lens.  (i.e. the viewer lens f.l. is shorter than the
> taking lens f.l.)  The opposite effect, stretch, is seen when the taking
> lenses have a wider field of view than the viewer lenses (i.e. the taking
> lens f.l. is shorter than the viewer lens f.l.).

Although I suspect this may be a semantics discussion rather than an
optical effect one, to me cardboarding is more commonly something else.
I think you well describe a source of cardboarding, but it doesn't seem
that source is an exclusive source to cardboarding.
	
To me, "cardboarding" makes me think of the effect I see most often
in lenticulars where I see a cascade of flat 2D images at various
depths.  Each "layer" (which may be as few as two or three) looks
to me like a cardboard cutout of whatever it is, and this set of multiple
cardboard cutouts put onto a 3D stage.  Viewmaster reels of cartoon
animations are this way too, as are 3D comic books I've seen.

I think you are very right that a telephoto lens portrait
could cause the same effect with things at the right distances
and w/o hyper "quasi-compensation".  I'm not sure if this is 
the only source of this effect though.  Certainly not in the
animation 3D's.  :-)

Mike K.


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