P3D Pentax SLR paired cameras with zoom lenses

[King3ddd@xxxxxxx]

In a message dated 00-02-06 17:59:05 EST, Kevin writes:

<< I am also rigging up two older Pentax SLR, but don't know if I should use 
 fixed lenses (28 or 50 mm) or zoom (28-80mm).  I like to buy the zoom lenses 
 for versatility, but afraid that it may be difficult, if not possible, to 
 match two lenses to the exact range and obtain the exact size pictures.  Any 
 advice out there?
  >>
To the best of my knowledge, using zooms in a paired stereo system is next to 
impossible (assuming that you are not planning to somehow pair the lenses so 
zooming one lens also zooms the other to the same degree).  Even if you could 
match the range of the lenses, imagine how tedious it would be every time you 
tried.  You would have to spend so much time comparing the 2 images, it would 
not be worth your efforts unless you only planned to take a very limited 
number of pictures.  When I use my Ricoh XR-10M's for hypers on two separate 
tripods, much time is spent lining up the verticals and horizontals, as there 
is no bar to depend on.  I can't imagine having to spend that sort of time 
and effort every time I took a picture.  You would end up only using the 28mm 
or the 80mm (or whatever the two extremes happen to be).  In that case, 28s 
alone are so small and light, there would be no practicality to using the 
zoom.

If anyone has information on a practical way to "synch" zoom lenses so only 
one has to be zoomed and the other would reliably follow, I would like to 
hear.  Also, how many mm's difference between lenses would it take to be 
bothersome and noticable?  Would less than 1 mm make a difference?  And how 
reliable are fixed lenses from the same manufacturer?  What are the 
acceptable tolerance deviations in manufacture? 

Sheldon Aronowitz