[photo-3d] Re: viewer optics. Brewster, Helmholtz, van Albada 1/2

["John Goodman" <jgood@xxxxxxxx>]

While I understand most of Abram Klooswyk's fine posts, 
there's one part that's not so clear (to me):

> When people have to accommodate in looking at the pictures,  
> they will set the viewer interocular to a separation which 
> causes proportionally viewing convergence. This important 
> point should not be neglected in these discussions.

As an enthusiast who is still discovering viewer variables, while 
trying to wean myself from constricting habits, I now make 
comfortable viewer settings by centering what the viewer 
lenses show of the left and right sides of a stereo mount, much 
as someone using a binocular would "center" individually 
circular images to create a unified view, of a bird, say, (by 
adjusting the included angle of the two monoculars).

I can't escape my 68 mm interpupillary separation, so it would 
seem logical, for most comfortable enjoyment of stereo views 
having a homologous infinity point separation several 
millimeters less than 68 mm, that some degree of 
convergence, provided by moving the centers of the lenses 
somewhat closer, is required. Or not? What would be the 
theoretical ideal interocular in this case? 68 mm (my 
interpupillary), 63 mm (the approx. homologous infinity 
separation), or some proportional in between setting based on 
slide, lens, and eye geometry?

[from part 2]

> one should bring the centers of the stereoscope lenses in
> the same distance from each other as the mentioned image
> points have, because only in this way far distant objects are
> looked at with parallel eye axes. 

If the viewer oculars are set to the infinity separation, and my 
pupils have a wider separation, how can I be looking at distant 
points in the stereo view with parallel eye axes? Or is the near 
point separation what is meant?

(I'm sorry if these are questions with obvious answers.)

jeg

 

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