P3D Orthostereo - was: Realist system flawed

["Ole Hansen" <olejohan@xxxxxxxxxxx>]

Dr.George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
> Subject: P3D Re: The ortho seat
> I am talking about the recording lens (lens used to take the
> picture) not the projection lens.  The projection lens does
> not matter... all it matters is the size of the projected image.
> then the "ortho seat" is at a distance equal to the diagonal
> of the projection screen.

This is only correct if the stereogram was photographed with
a lens of normal focal length.
I prefer to describe orthostereo as a stereogram viewed under
the same viewing angle, as you as an observer would have seen
when being present and located at the standpoint of the camera
whwn the picture was taken.
As human vision is "constructed", this implies a viewing angle of
45 to 50 degrees, and that is why the Realist format usees a
35 mm lens.
The viewer lens must be of the same focal lengt, and for projection
you should see the stereogram under an angel of 45 to 50 degrees.
That implies, that the bigger the projected picture, the farther away
you should placed from the screen to get the orthostereoscopic
viewing angle of 45 to 50 degrees.
regards - Ole Hansen - olehansen@xxxxxxxxx


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