[photo-3d] Realist red button viewer (the good and the bad)

["Dr. George A. Themelis" <drt-3d@xxxxxxx>]

John Goodman wrote:

> In my (limited) experience, I've found considerable difference 
> between average red button Realist viewers and later examples, 
> the legendary Realist black button viewers. Though the 
> specifications are identical, even when viewing 5p stereos there 
> are certain Realist viewer lenses that offer a noticeably flatter 
> field, greater peripheral clarity, and more viewing pleasure than 
> their brethren. Unfortunately, they are scare and are spoilers, 
> but do help when viewing wider than 5p in doctored Realist 
> viewers.

In my (extensive - hundreds of viewers examined) experience,
the difference is mainly a matter of contrast and not optical
qualities like peripheral clarity or flatness of field.

Also, it is not only the "black" red-button viewers that show 
improved clarity.  Also, earlier viewers and later viewers
(with red buttons).

There are ways to tell the early and late viewers... Early
viewers have unplated contacts and flat reflectors.  Very
early viewers (rare) have a slightly different logo and a
black *metal* focusing knob.  Late viewers have larger
side holes, unplated contacts, curved reflectors.  Very late
viewers (not as rare as the very early viewers) have a black
switch button (instead of red) and the later ones also a black
*plastic* focusing knob.  (unplated contacts have a yellow
color - they are just unplated copper - and might need more
frequent cleaning)

What creates this difference in contrast?  I believe it comes
from the cement used to hold the two elements together.  The
"clear" lenses have clear interface.  The "hazy" lenses show
a dispersion at the interface.  This can be seen if you shine
a bright light beam at a slight angle.  Things get worse the
brighter the viewer is (using halogen bulb, etc.)  If the light
is dim (like in no. 14 bulb) you will not notice the difference.
(Actually, bright light amplifies any optical problems so I
recommend dim light in inferior viewers).

The "clear" and "hazy" lenses look identical but either a 
different supplier was used or the same supplier changed 
the type of cement used in the lenses.

There are variations in the difference in contrast.  Sometimes
it is only noticeable by comparing two viewers side by side
viewing the same slide.  Other times it is obvious that the
natural reaction is to try and clean the lenses, as if they
are dirty/fogged (but they are not).

I would estimate that 1-2 out of 10 red button viewers have
the crystal clear lenses.  When I get one of these, I always
price it higher than the rest.  I have placed a few in ebay,
clearly emphasizing their advantage.  These viewers, modified
for 8p, halogenized, painted, polished, etc., usually bring
$200.  A run-of-the-mill viewer could sell from $125 to $175.
So buyers are only willing to pay a small premium for the
crystal clear lenses (only $25-$50).

BTW, my very own viewer, which I got in the NSA convention in
Cincinnati in 1988, has crystal clear lenses and is not an early 
or a late viewer.  This viewer convinced me of the quality of
the Realist red button optics and mechanics.  After 13 years of
continuous use, it looks ugly, has a repaired crack and the
insides are a mess, due to constant experimentation.  But I
still love and use this viewer!  It also has my signature in 
Greek.  There is only one viewer that has this "feature".  It 
belongs to Mike Chikiris.  I would be happy to do it to other
viewers too but have not been asked to do so.

George Themelis



 

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