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Proceedings Paper

Constant Light Output Ballasting For High Intensity Discharge Lamps
Author(s): Adrian Donkin
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Paper Abstract

Since the commercial introduction some twenty years ago of HMI* (Hydragyrum-mercury, Medium, Iodide) type lamps, as a source intended primarily for floodlighting applications, their attraction as a cinematographic light source has been apparent due to their largely desirable characteristics. Use in this field has been restricted due to the absolute requirement for an alternating current supply - with a sine wave supply frame rates are limited to a sub-multiple of the supply frequency with the supply frequency phase locked to the camera frame rate. This has effectively barred metal halide HID lighting from use in high speed photography. The general characteristics of metal halide HID lamps are presented alongside a sample of other light sources. An electronic ballast which has been proven to 12000 Watts in the motion picture industry is then described which overcomes the limitations of the conventional magnetic ballast - the square wave output of the electronic ballast theoretically allows the use of any camera frame rate/shutter angle combination. Finally the suitability of luminaires for high speed photography is discussed.

Paper Details

Date Published: 4 February 1988
PDF: 8 pages
Proc. SPIE 0832, High Speed Photography, Videography, and Photonics V, (4 February 1988); doi: 10.1117/12.942249
Show Author Affiliations
Adrian Donkin, Lee Colortran Limited (England)

Published in SPIE Proceedings Vol. 0832:
High Speed Photography, Videography, and Photonics V
Howard C. Johnson, Editor(s)

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