[tech-3d] Re: Fw: Your latest ref the Stereo Base formula (to M. Davis)

[boris@xxxxxxxxxxxx]

Allan and friends:

you wrote to me:
>course, it would be interesting to assess what it is you claim that you have
>learned!  I certainly wish I could learn only a slice of what you know about

Aside from getting the formula, I learned that the retinal deviation may be
variable, though the actual on-film (or -screen, or -print) deviation is
constant and given.  I.e. I learned that viewing parameters for prints are
analogous for those of stereo slide viewers, and should not be ignored.

>Just as an example, Boris.  I remember you stating that you are a "depth
>demon".  ...achieved by increasing the allowable on-film deviation ...
>up to 2.00mm in cases where you can bring some of the subject through the
>window.  These values don't appear to present a problem in hand viewing.
>Its with projection, where the real test of what is too much deviation,

Well, my Pixie image, which has minimal window violation in foreground, has
something like 3 or 4 mm of deviation.  I've never had anyone complain
about too much depth - including stereo neophytes, who are less able to
accomodate extreme depth - and it has won numerous awards (projected).  I
believe one can sustain greater depths as long as one leads the viewer's
eye into the depth with some physical guide in the image.  In the case of
the Pixie that is the plane of water.  Also the objects at greatest depth
are very pale, so that rivalries (with nearby objects) do not distract as
much.  Certainly there are other images where less deviation can be
distracting or difficult to view.

So I totally agree with your intent in this discussion, which is to point
out that mathematics and formulas alone cannot guarantee good stereo image
results.  The variables are indeed numerous, and some are not even numeric!

>
>When you say that you hope to use this "magic math formula" to help you
>reduce the amount of "differential" or potential areas of ghosting in your
>anaglyphs, this can only be done by reducing your stereo base or on-film

I did not say that.  I said that I want to control depth in anaglyphs.  TO
design an image for a particular size anaglyph print, you need to vary your
taking geometry as appropriate - the equation helps in this work.  (If I
know an image will be presented in a magazine at three inches wide, to be
viewed at 1/2 arms length, I need to take a very different shot than if it
were presented at 30 inches wide, to be viewed from six feet back!)

But since you bring it up, yes I do want to minimize ghosting.  This I
achieve with composition.  Beyond even minimizing ghosting, I try to hide
or integrate the deviation in objects of greater depth into the picture, so
that it looks good FLAT too.  This is the focus of my current exhibit here
in Charlottesville.  Just in case you can't visit, you can review my
(non-math) thesis here:
http://www.starosta.com/3dshowcase/technobot.html

>matter.  Stereo is like the weather.  The variables are as numerous.

Allan, you had responded to my words:
>> others, they sounded useful to me.  I am presently exploring variable
>> stereobase photography to control apparent depth in anaglyphs.

________________________________________________________________________
Boris Starosta, 3d artist             boris@xxxxxxxxxxxx
Dynamic Symmetry, LLC                 http://www.starosta.com
usa - 804 979 3930                    http://www.starosta.com/3dshowcase

Currently showing at The Observatory. Info: ...3dshowcase/technobot.html



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