Paper
4 February 1988 Constant Light Output Ballasting For High Intensity Discharge Lamps
Adrian Donkin
Author Affiliations +
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.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Adrian Donkin "Constant Light Output Ballasting For High Intensity Discharge Lamps", Proc. SPIE 0832, High Speed Photography, Videography, and Photonics V, (4 February 1988); https://doi.org/10.1117/12.942249
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KEYWORDS
Lamps

Metals

High speed photography

Light sources

Light sources and illumination

Cameras

Photonics

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