P3D Re: Older people with glasses...

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

In the church group that I mentioned, I noticed that everyone was wearing
glasses.  I mean EVERYONE.  After the slide show I tried to pass around a
red button showing a few slides that were seen earlier in projection.  From
the expression in the people's faces, I knew that something was wrong.  I
am not sure what these people were seeing... but it is definitely not the
same thing that I am seeing. 

This reminded me the story when Brewster went to France to have a viewer
made and tried to show his viewer and stereo cards to members of the
Academy of Science in Paris.  It is reported that none of the members
showed any interest.  As it turns out, every single member that looked at
these pictures had a vision problem that prevented them from seeing stereo,
including a member with only one eye!  It's been calculated that the
changes to hit so many "stereo blind" people in a row, is very low... but
these calculations are based on the average population.  The members of the
academy approached by Brewster, were OLD.  Some of them in their 90s.  I
don't have any data (sorry Greg!) but I imagine the probability of having
vision problems that interfere with stereo perception increases with age. 
I have nothing against older people and I love to listen and learn from
them, but this might not be the best group to get interested in stereo.

I also have nothing against people who wear glasses.  I wear a pair of
glasses in projection (:-) sounds like a joke but I mean in addition to the
polarizing glasses).  But when I see a person who wears glasses, I hesitate
to pass them my red button viewer.  The lenses of this viewer are just too
small to work well with glasses.  It might take some "getting used to". 
The stereoscope with its bigger lenses might be better.  Simple lenses
(like in a Brumberger) might work better than short FL achromatic lenses
(like in a Realist)

In the discussion of slides vs. prints, the viewer rarely comes up.  I tend
to believe that certain people do not enjoy slides very much because they
do not see a good image through the viewer.

George Themelis


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