T3D Stereo base equation is too complicated: Please help me distillit!

[Dogbreath <hopi@xxxxxxxxxx>]

Hi.

After poking around on the Web for a while looking for answers regarding
stereo base calculation, I was directed to what was, apparently, the
definitive equation. It was very complicated and filled with obscure
variables which seemed to me to be the sort of information that would be
inconvenient at best to gather. It seemed to take into account both the
nearest and furthest distances to your suject along with some weird
coefficient. Not being an engineer or a mathematician, it was, frankly,
intimidating. So, my question is, can this imposing equation be distilled
to a more modest and, perhaps, slightly less accurate one? I don't need
precision so much as convenience. I think the one-in-thirty rule represents
the ultimate convenience, but can it work with lenses of focal lengths
other than 35mm? I think I've learned that while you may adjust your base
depending on your focal length, you must still take into account that your
viewer's base is fixed (mine is a Kodaslide) at 35mm. Is it pointless then
to even make stereo exposures with lenses other than the Realist-based 35mm
if you intend to view them in your Red Button? I realize that a 200mm tele
might be unwise, but how about a 20mm? I've tried some pairs shot with a
21mm and I confess that only the center of the image seems to "work." I
think the perimeter is transformed too significantly with even the most
discrete stereo base, so by the time you employ the focal length as divisor
method, your base is far too wide for good viewing.

And what about larger formats and stereo base? Can one still employ the
one-in-thirty rule even when using a 210mm lens? I mean, after all, the 210
is still "normal," so you'd expect the rule to stand up. Does it?

Thanks for your time. Oh, and BTW, please don't just steer me toward
another scientifically oriented web site on the subject. I need
simplification right now, not more esoterica to wade through.

Dwib




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