P3D Re: RE: P3D Re: Close Focussing Realist

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

>Another factor is that the Realist has a built in stereo window, 
>at 7 feet.  Taking a picture in real close and mounting it in a
>standard mount -- which is what would have happened with the lab 
>processing available when the Realists were sold retail  --would
>cause real problems.

This is a "real" problem (not imaginary) but not a serious problem.
Consider this:  The built-in window is at 7 feet but the camera
will let you focus as close as 2.5 ft.  Mounting a close-up in
normal mount still results in a stereo pair that can be viewed.
Only the window is not placed properly.  

To overcome this problem you will need to use close-up or 
half frame mounts.   

Another way to overcome the problem is to use *prismatic* close-up lenses.
These have a wedge shape and need to be oriented properly.  They shift
the image to eliminate the "image loss" that occurs in close-ups.
Prismatic close up lenses exist for the View-Master and also in series
V, etc. for stereo cameras.  I have tried one rather strong close up
filter and noticed keystone distortion in the image.

George Themelis


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