P3D Re: Cardboarding

[boris@xxxxxxxxxxxx (Boris Starosta)]

>Date: Thu, 22 Jan 1998 16:30:00 -0800
>From: michaelk@xxxxxxxxxxxxxxxxxx (Michael Kersenbrock)
>
>Although I suspect this may be a semantics discussion rather than an
>optical effect one, to me cardboarding is more commonly something else.

Exactly the problem.  Because I think cardboarding is a very subtle effect
in most slides, many people (you all) have different thoughts about it,
different perceptions of it.  Nevertheless, I propose that it is a
definable optical effect.  My proposal specifically hopes to overcome
semantics.

>I think you well describe a source of cardboarding, but it doesn't seem
>that source is an exclusive source to cardboarding.

In stereo photography not involving cardboard subjects, I propose that it is.

>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.

Actually, my theory would apply/explain your impressions of lents quite
well.  It is likely that you look at your lent. print at a pretty good
distance, say one to two feet.  The "field of view" of the lent is thus
fairly narrow, certainly much narrower than the taking lenses on the
camera.  Thus you are experiencing the equivalent of a longer f.l. viewer
lens and shorter f.l. taking lens.

>Viewmaster reels of cartoon
>animations are this way too, as are 3D comic books I've seen.

And undoubtedly that is where the definition of "cardboarding" comes from.
As you say, these might have actually contained "cardboard" subjects.  But
I thought we were discussing the effect as seen in actual optical stereo
photography.

>
>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".

Now you're throwing in another variable, namely stereobase.  Attempting to
compensate for cardboarding by extending the stereobase will fail, as was
discussed on P3D late last year (I think - certainly within the last six
months).

Respectfully submitted,



Boris Starosta

usa 804 979 3930

boris@xxxxxxxxxxxx
http://www.starosta.com
http://www.starosta.com/3dshowcase

"A lifetime can be well spent correcting and improving
one's own faults without bothering about others."
- Edward Weston

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