P3D double depth?

[bercov@xxxxxxxxxxx (John Bercovitz)]

>> If an image has too great a total depth for instance, NO
>> position of mounting will give 100% Ortho results. 

> John B conducted some actual experiments a year or two ago, that would seem
> to contradict that statement (depending on how you define "too great").
> If I recall correctly, John took stereo pairs with too much depth for mounting
> to the stereo window, and was able to mount them so that this excess depth
> could be used.

I'm not sure to which experiment you're referring.  I did one which 
is essentially double depth in which I utilized the fact that the RB 
viewer has IPD adjustment and used same to set the IPD to my eyes 
(67 mm) and then set infinity out there too using standard mounts so 
essentially I pulled the window in way close and was able to use that 
for a scene with a lot of depth.  1 m to infinity is no problem but 
0.5 m to infinity is a bit dicey.  I did select the scene carefully so 
that nothing in the near foreground occluded anything in the distant 
background so that local stereo disparities would always be low.

Another experiment was the disproving of the conventional 1 in 30 
rule.  In that one, I made a slide which anyone can view that had 
near and far objects at 1.8 and 2.2 m and a stereobase of 190 mm.  
That pair should show excessive depth if conventional wisdom is 
correct.  The pair did just barely stay within the maximum allowable 
on-film deviation (maofd) rule of 1/30th of the focal length of the 
system, though.  So I favor maofd over the conventional rule.  

Is either of these the right experiment?
 
John B


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