Twin Camera Questions: Toe-In, Hyper & Zoom

[Mark_Poole@xxxxxxxxxxxxxxxxxxxx (Mark Poole)]

     I have some questions related to Twin Camera setups, based on 
     some recent posts.
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     Background:
     Pair of Minolta 7000i's 
     Triggered simultaneously by Infrared Master & 2 Slaves
     3 foot & 6 foot Slide bar (for hyperstereo)
     Bogen Tripod (heavy-duty) with bubble levels.
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     [1] I have 35mm 35-75 autofocus zoom lenses on each.  From what I 
     can gather, am I supposed to use a setting that matches the lens 
     of the projection system (or viewer)?  What if that changes? I 
     use the Franka Twin 35mm Slide Viewer (does anyone know it's 
     focal length?).
     What if I am projecting the image (which I've never done), can 
     the slide projector compensate?  Isn't "normal" about 52mm on 
     35mm equipment? 
     
     [2] Toe-in.  I thought this was not done (so much for book 
     learnin', John Boy).  It does make sense that the eyes can 
     converge for close-up viewing.  But what happens when you view 
     with parallel viewers?
     Can I get away with this to compensate for the wider than normal 
     interoccular distance of my camera lenses (a good 4 inches or 
     so)?  Will toeing cause eyestrain on the audience?  
     
     [3] Hyper-stereo.  I have heard (or read & forgot the source) of 
     1 to 30 or 1 to 40, ratio of the distance of lens separation to 
     nearest object in photograph.  Does this sound right?  I have an 
     aluminum bar that is 3ft wide (and thinking of adding a 6ft).  I 
     use this mainly for landscapes (views from the Blue Ridge 
     Parkway).  Related to the two questions above, what if I want to 
     include an object closer than the 1/40?  Can I toe in on this one 
     object without popping peoples eyes out?  Can I use zoom to bring 
     that object in closer?  Longer length tends to flatten 2d images, 
     does this still happen in 3d?
     
     I have tried zoom in hyper, but I failed to record exactly which 
     images I did it on and  what setting I used on each, so I have no 
     good way to quantify it. I guess I could get off my lazy rear-end 
     and do some scientific method testing, but I would appreciate if 
     anyone could provide me some rules of thumb.
     
     I am in the process of redesigning my twin camera rig, and need 
     to know if I should provide a method of allowing toe-in to the 
     sliding camera carriages.
     
     Thanks,
     Mark
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     Mark Poole               |  Mark_Poole@xxxxxxxxxxxxxxxxxxxx 
     The ants find kingdoms in a foot of ground -William Rose Benet 
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