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Full-Frame 35mm Fastax Camera
By JOHN H. WADDELL
A full-frame 35mm rotating-prism type camera is described and its features discussed. The camera has a 500-ft capacity and a picture-taking rate of from 100 to 2500 frames/sec.
H,
.ISTORICALLY, five major 35mm full frame high-speed motion picture cameras have been designed. Jenkins designed one employing a rotating-lens system, later Zeiss and then Wyckoff and Partsch designed a camera using the same principle. Edgerton built one synchronized with flashing high-voltage gas-discharge tubes. Chesterman and Myers designed one using a rotating prism. And there have been several other single cameras, built for specific purposes, some of which used rotating mirrors.
Rotating-Lens Cameras: Herbert Grier, of Edgerton, Germeshausen and Grier, stipulated that measurements from highspeed camera films be accurate to T^ of 1%. It is almost impossible to find 20 or more matched lenses for a rotatinglens camera whose focal length can be maintained to give films within the y1^
Presented on May 1, 1953, at the Society's Convention at Los Angeles, by John H. Waddell, Industrial and Technical Photographic Div., Wollensak Optical Co., Rochester 21, N.Y. This paper was scheduled in the International Symposium on High-Speed Photography held at Washington, October 1952. (This paper was received October 8, 1953.)
of 1% requirement, under varying conditions of temperature.
RotatingMirror Cameras: These are potentially better but the film drive is rather complex. The optical performance of mirrors is an attractive argument in their favor.
Cameras Using Synchronized High-Voltage Flashtubes: In a camera with no shutter, the flashtube must fire very fast, for reasonably high picture-taking rates. The resolving power desired in cameras today must be better than 50 lines/mm, or the individual line would be 0.01 mm or 0.0004 in. To assure good image quality with a moving film, this film should not move more than 0.0002 in. during exposure. The study of the effect of film velocity versus time of exposure to obtain this quality is:
Time of flash
1
10
100
1000
Velocity of film to
get 0.0002-in. smear
(ips)
200 20 2 0.02
It is to be noted that the high-voltage lamps, when used in conjunction with
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November 1953 Journal of the SMPTE Vol. 61