Re: [tech-3d] Re: Stereo Base Calculation With a $20.00 Handheld

[boris@xxxxxxxxxxxx]

Mike:

>Nice web page design too!

Thanks, I like simple and unadorned and fast.

>shoot mostly landscapes.)  Now I can accurately calcuate base for any Near
>or Far, instead of interpolating from my spreadsheet.

Great for me too, as with portraits I rarely have infinity (indeed I avoid it).

>    (Viewer FL/Camera FL) * C
...
>The new equation would look like this:
>
>    1.2C*((304.8AB/(B-A))*(1/65-1/(609.6AB/(A+B))))
>
>Again, using this equation, C is the actual desired on-film deviation and
>the constant 1.2 compensates for a 78mm viewer focal length being longer
>than the 65mm taking lenses.  If you make the camera FL a variable,
>remember to substitute the other constant of value 65 (in the middle of the
>formula) with that variable.

I have a question.  Why does a viewing device focal length (i.e. a viewing
geometry) even come into play?  On film deviation is the product simply of
camera optics, stereobase, and near and far point.  Why the viewer F.L.?
Granted, the viewer optics affect the perceived depth, but it certainly
does not change OFD.

(And for my application, in shooting for anaglyphs, there is no viewer F.L.
There may be a print size, and a viewer's naked eye distance to print -
that would form the equivalent to a viewer's focal length.  But to shoot
for a specific size anaglyph print, and therein a specific deviation on
paper, I want to predict and set up a shot simply for a particular
deviation on film.  Viewer optics are not otherwise considered.)

Boris

________________________________________________________________________
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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