Re: PHOTO-3D digest 1169

[bobh@xxxxxxxxxxxxx (Bob Howard)]

RE: Phil Palmer..3D Stereo 35mm apparent "half-frame"?

Hi Phil glad to see you join us. The near half frame format is really
22.5 x 24mm (movie or Leica half-frame is 18x24mm..Leica being two
movie frames which resulted in movie frame being called half-frame??).
It was convenient to use that size to get two frames between the
active frames behind the lens and simplify the winding. This results
in the lens separation being a big more that ortho or eye spacing. One
camera the TDC Stereo  VIVID achieved ortho by building a ramp in the
film plane to absorb the extra distance of the two frames and allow
closer spacing. The frame discussed so far is the American 35mm stereo
format started by Realist. The European format of 24x30mm is near full
frame 24x36mm and very pleasing, but doesn't have commercial mounting
as still available for the Realist size. It requires a complicated
film wind and is available in the few European models such as the
Busch (Richard) F40 Verascope or the modern FED Stereo Russian camera.
True full frame is
done with pair sycned cameras and special holders and viewers but
mostly used for projection. BobH


------------------------------