[photo-3d] Re: Kodaslide II

["Chuck Holzner" <cfholzner@xxxxxxxx>]

My use for ortho stereo photography:

I maintain some TV translators on mountain top sites in the 
Shenandoah Valley.  Each site has a tower with several receive and 
transmit antenna on it. A problem that sometimes occurs is that the 
wind or something or someone will turn one of the antennas so that it 
no longer points in the proper direction giving less then desired 
signal levels. It doesn't take much movement to be a problem. 
There 
are several problems that can cause a loss of signal and can be fixed 
without climbing the tower and so antenna positioning is the last one 
tested.
It would be useful to be able to look at the antennas from the ground 
and determine if any have moved since a time when I knew all were 
pointed properly.  A stereo slide that could be viewed on site could 
be compared to the site to give a "Then & Now" comparison.
It would work best if the view in the viewer appeared to be the same 
size and depth as the view directly.  One could even use one eye in 
the viewer and one directly to the tower to see minor differences 
with some practice.

The problem:
No Realist viewers with 35 MM FL lenses are readily available. 
Can't 
find a Realist gold button and likely couldn't afford one if I
did.

Solutions:
I could go to a Sputnik and use the 6X6 (6X13 slides) format.  
Viewers to match the FL of the Sputnik are available.  However, the 
larger format is not handy to use, much more to carry up the mountain 
along with my tools and test equipment, and has a higher cost for 
film and mounts.

A 35 mm camera and viewer would be preferred, both with the same FL 
lenses.
Since all my realist format cameras have 35 MM lenses and I can't 
find a 35 MM FL viewer, I would have to make one.

More Problems:
Suitable lenses are not available.  Don't know what the Gold
Button 
used.  

Experiment:
Can an existing viewer be modified to 35 MM lenses by adding close-up 
lenses?  
I calculated that if I could add a 200 MM (5+) close-up lens with the 
43 MM lens of the Kodaslide II it would result in a FL of 35.39 MM.  
That seemed very close to where I wanted to be.  I located two such 
lenses and added them to the Kodaslide on the slide side of the 
lenses.  
It seems to work.  One problem I have is with advancing age I have 
become far-sighted.  As a result, I have to focus standard viewers at 
or near one end of their focus range.  
 With the modification, the focus range is now better centered for my 
eyes.  I have had others who are not far-sighted use it with no focus 
range problem.  I have yet to try it on a near-sighted person.
Since there is more magnification, the focus adjustment is a little 
touchier, grain is more visible, slide misalignment is more 
noticeable, etc.  Incentive to use finer film and mount better.

Testing:
Now I need to test it. I have made comparisons using slides I have 
taken from my front yard and can't detect a difference in the
image 
size, wouldn't know weather to add magnification or subtract it. 
I 
can't detect that the 35.39 MM lenses are not 35 MM lenses.   
I plan to carry slides to the sites where I took them and do some 
comparisons.  I am not an Optical Engineer, if there is any problem 
you think I should be looking for in the viewer let me know.

Thanks,

Chuck