Re: Window reversal

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Dr. George interprets Bill Walton's description of window reversal:

>Bill, what you call "window reversal" we call "window violation".
>This happens when the window is placed past objects that intercept
>it.  (or for the rest of this list, these objects are placed
>in front of the window).

With all due respect to the good Doctor, I don't think that's what Bill
was describing at all.  To me it sounded more like the situation that
results when you photograph a subject which is closer than the 7-foot
window with a Realist.  You end up with "extra stuff" on the outer edges
of both views which has no correspondance with the other.  Hence the need
for a narrower "close-up mask" for such close-up slides.

In print mounting, I think this would come about if your closest object
spacing was reduced to less than that of the mount's window centers.  The
view would still converge (in fact would be easier to freeview) but the
window's edges would not also be converged.

If my interpretation is correct, I'm not sure why this is called "reversal",
exactly, except that the "extra stuff" is on the wrong side of each image
(outside instead of inside).  But it has nothing to do with the window,
per se.

	-Greg W.


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End of PHOTO-3D Digest 2142
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