Lens Separation calculations

[P3D <LeRoyDDD@xxxxxxx>]

John Ohrt wrote...

"Say the object your are trying to photograph has nothing of significance in
the forground or background and these areas will be ignored by the viewer,
but the object itself has features best displayed by 3d.

Suppose the aparent viewing distance you wish is five feet but you can't get
closer than 10 feet.  Can you just double the lens separation (ie. from 62mm
to 124mm) to achieve the desired effect, or is there a whole lot more I have
to know?"

     I think I'd just take the photo at ten feet. Messing around with getting
twice interocular is putting too fine a point on it for me in a situation
like this.
     If I think I'll be able to see some(enough, good enough for my taste,
almost any) 3-D effect in subjects at 50/100/200 feet, I kind of like to
enjoy the space in front of the subject, too.
     The formats I can afford always give me a window frame which I can put
anywhere in the image, so I *always* have something in the foreground.

     An important part of John's question is the "nothing of significance in
the forground or background" condition.
     If I doubled the lens spacing to increase the depth in an object at ten
feet and had an "insignificant" object in the frame at five feet as well as
"insignificant" objects at infinity, the result would be an image with stereo
deviation like an image with objects from two and a half feet to infinity. A
difficult image to view for most. And you won't have much success telling
people to ignore the foreground and background.
     An important point for many scenics is that, except for elevated
viewpoints, the ground(whatever the photographer stands on) is in the scene
so hypers are difficult to do well.

LeRoy Barco
LeRoyDDD@xxxxxxx


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