T3D Re: extending MAOFD to projection

[Tom Deering <tmd@xxxxxxxxxxx>]

On 9/22/98, john bercovitz wrote:
>> I've heard over and over that I need to put less depth in my slides if
>> I want to project them.  The common number I hear is "half as much."
>>
>> How do I reconcile this with the MAOFD formula?
>
>All you need to do is change the allowable on-film deviation to suit.
>1/30th of the focal length (1.2 mm in the 35 mm lens system) should
>work for projection, and if you want to try twice as much for hand-
>held viewing, then use 1/15th which is 2.3 mm.  On the maofd spreadsheet,
>just insert 2.3 mm instead of 1.2 mm in the cell where it says "Max.
>allowable on-film deviation:"

Right.  I assumed this much.

What I meant was, what is the geometric reasons for putting less depth in
projected stereo pairs?

I assumed it was because the projecting lens was nowhere near 35mm. But
hanging around here has taught me not to assume I know what I'm talking
about.  :^)

If that is actually the reason why, how could I manipulate the formula to
take this into account?  (I would not usually try for such mathematical
accuracy, but I am working on some demo graphics which require such
specificity.)

Cheers,

Tom



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End of TECH-3D Digest 363
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