P3D Re: Depthmaster/Stereo Graphic

[Rod Sage <rsage@xxxxxxxxxxxxxxxxxxxx>]

>IMO, a bad idea.... it is supposed to work for cameras with
>fixed focus (the TDC Vivid is not one of them), fix one lens to
>focus at a close distance and the other lens to focus at a
>further distance, so at least one eye sees a sharp image...  The
>only camera I know of with this feature is the Stereo Graphic
.which calls it "Depthmaster".

>George Themelis

I have never owned a Stereo Graphic but I recalled this ad from Reel 3-D
News 1980:
"Matched f4 lenses are positioned to overlap depth of field, providing
positive, sharp foreground detail and equally sharp background. When
viewed, the stereo pair has amazing depth of field- unmatched by any
other stereo or single lens camera. Graflex developed Depthmaster
Auto-focus has been reviewed by personnel of a nationally known
technological institution, many photographic dealers and a panel of more
than 1,000 photographers. Ask your dealer to show you slides taken with
the Stereo Graphic ....and see the greater depth yourself".

Then there is an illustration showing one lens focussing from infinity
to 7.5 ft. and the other lens focussing from 30 ft. to foreground.

Theoretically it makes some sense for a fixed focus camera. I would
assume if the camera is stopped down to f8 or more, both lenses would
focus to infinity and near focus would be to about 5 ft. and 2 ft.
respectively.
I believe the camera also has a simple shutter with only B and I (which
I believe is 1/50).  So in the 1950's when slide film was rated at about
ASA 12 it would be difficult for anything above 5.6 to be used on a
bright day.
It seems that the smaller apertures could only by useful for flash
photography or time exposures.

Roderick