Re: Converging lenses (was: Window reversal); D|s-TortiO|\|s

[P3D Michael Kersenbrock <michaelk@xxxxxxxxxxxxxxxxxx>]

> That is very true, and a little bit of keystoning is not objectionable.

Some keystoning is not objectionable, but keystoning is forbidden
territory? 

Some people telling how *terrible* beamsplitters are like
to mention that it has *keystoning* (and therefore is horrible) but 
in many images (when remounting for non-splitter-viewers) you can 
barely tell if it's  there (if at all).  Or at least that's been
my experience with my beamsplitter.  I've been making dupes which
I then split and put into 4-perf "realist-format" mounts.

> I'm pretty sure there is alot of ways that would justify taking a picture
> of a tree, by using the varied distortions of 3D or 2D cameras, such as
> lighting, focal length, etc. without ruining the image. No one is saying

I'm interested in those justifications.  Note that taking a pristine 
photograph of a tree for the purpose of showing what a tree looks like 
is an "artistic justification". One portion of painting styles is, 
for instance, "realism" (or some such term).


> Mike, you seem to have a fixation with ghosts. :-) So I submit one of my
> creations from Halloween. Check it out, if you haven't seen it then, at
> http://www.generation.net/~jacob/ghost3d.jpg
> Anaglyph and no keystoning, of course. Sorry. ;-)

Are you saying that your rendition of a ghost is more realistic and 
therefore more valid than a keystoned one?  What if I claimed that
ghosts look keystoned and that yours is gross distortion with
the keystoned look left out?

I don't mean to go down the dead-end path of using "artistic" as a 
blanket justification argument, however, I also don't think that using 
artistic-ness as a blanket anti-argument is valid either.  Because *any* 
image is an artistic rendition, it can be rejected by just saying 
"that's artistic and doesn't count".

I think keystoning can be used and NOT be painful to the viewer. This
has been demonstrated with my beamsplitter experiments.  This isn't
to justify keystoning as a standard thing to do -- but that it can be
done without any compelling justification NOT to do it.

So the answer to "why" is "why not?".

Mike K.


P.S. - I've been reading another (British written I think) 3D book from
       the early 50's, and it uses the term "beamsplitter" profusely.
       I think it's stuck in my brain, even if not technically correct. :-)


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