P3D Re: Lasers

[wier@xxxxxxxxxxxxxxxxx (Bob Wier)]

>On certain Speed Graphic or other press cameras with Kalart type
>rangefinders. They shine a light backwards through the rangefinder so
>that two light sources are projected onto the subject. Then the camera
>is focused until the two lights line up. This way the camera can be
>focused in total darkness. I wonder if a laser or plain flashlight bulb
>could be projected though any rangefinder.
>RDS

I have one of those Speed Graphics - I didn't use the projected light finder
very often, but it was handy occasionally. This suggestion brought to mind
a problem during world war two where an airplane needed to fly very precisely
above a body of water during a bombing run ("The Dambusters"). This was
at night, so what was done was two spotlights were mounted on the plane at
an angle that they would coverge to a single dot on the water surface when the
desired height was used (about 50' as I recall). An interesting low tech 
solution to a knotty problem of the time.

THANKS

              Bob Wier
     mailto:wier@xxxxxxxxxxxxxxxxx
   10:32 PM Thursday, November 5, 1998
        Unix/Internet Administrator
   Rocky Mountain College, Billings MT.
 keeper of the Photo-3d and Overland-Trails
mailing lists and the USA GPS Waypoint server



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