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[MF3D.FORUM:621] Slide Bar Stereo


  • From: "Oleg Vorobyoff" <olegv@xxxxxxxxxxxxx>
  • Subject: [MF3D.FORUM:621] Slide Bar Stereo
  • Date: Tue, 30 May 2000 18:57:42 -0700

Bill Glickman wrote:
>...it sounds like even the slightest leaf or branch being out of place
>will play havoc with ones ability to fuse subjects...

No! No! No!  Don't give up on the slide bar, single camera option.  Out of the
many hundreds of stereo pairs I have taken, well under 10% have any visible
motion disparity.  Of those, only a small fraction are difficult to view.  Of
course, I take only suitable subjects.  But they are all around - it is
surprising how little the world changes in the two or three seconds it takes to
fire off a stereo pair.  My biggest problem has been wind and traffic
(vehicular, pedestrian and avian, mainly).  By waiting a bit, I can usually find
a lull in the motion.  To keep from getting frustrated, after setting up my
tripod and camera, I set my watch to count down ten minutes.  The waiting then
takes on a Zen-like calm - just taking it all in.  If I do not get a lull in
that ten minute period, I figure the picture is not to be, and move on.

The slide bar is also great for closeups.  Closeups are even easier to find
motionless.

>If I were to mount my two M7 80mm lenses on a view camera
>lens board, they still will not be 65mm apart, but can get to
>about 70mm.  Will this extra 5mm spacing ruin the desired effect?

There is no "effect" at 65mm.  I doubt you will see a difference between a 60mm,
65mm and 70mm stereo pair if you viewed them one after the other.  By 100mm you
will probably see a difference, and more likely than not, the 100mm pair will
look better.  If you have not already done so, shoot some (or better yet, many)
rolls of 35mm film using a zoom lens with the camera on a slide bar .  Try
different focal lengths and stereo bases on subjects you typically shoot.  View
the slides in a 2x2 viewer.  That procedure was very educational for me.

>Any holes in my thinking?

I am afraid you will find extraordinary modifications to create a rig with 65mm
spacing to be a waste of time and money.  I would suggest carrying a rig with
100mm spacing and using one of the cameras on a slide bar when coming upon a
subject that demands a shorter stereo base.

Oleg Vorobyoff