Information AboutEllipsoidal |
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Ellipsoidal, or '''Ellipsoidal Reflector Spotlight''' (abbreviated to '''ERS'''), is the name for a type of Theatrical Light , getting the name from the Ellipsoid al Reflector used to intensify the Light of a back-loading Lamp through the Barrel and Lens . Ellipsoidals are used for their strong, well-defined light and their versatility. ''Leko'' and ''Source Four'' are Brand Names which may occasionally be used to refer to any sort of ellipsoidal. Characteristics of an ellipsoidal lighting unit include:
The ERS improves over the efficiency of the Fresnel Lantern by surrounding the bulb in an ellipsoidal reflector, as opposed to the spherical reflector of the fresnel. This results in a much more controlable beam of light, which is typically shaped inside the instrument, through the use of shutters, as opposed to externally, using barn doors. The biggest advantage of the ERS is its lower Power consumption; the cost savings in electricity offset the higher initial cost of the instrument. 750 or 575 Watt lamps are typically used, rather than the 1000 watt lamps common in older models. They generally provide better illumination and produce a cooler beam of light, due to the dichroic reflectors, employed on modern models, which reflects only the visible portions of the spectrum. The lamps are loaded from the rear, and either mounted Axial ly, or vertically with the base either up or down (the orientation is important when mounting the instrument). The Filament of the bulb is at one focus of the reflector and the aperture to the lens housing at the other. The shutters and gobo are ideally in focal point of this aperture. Ellipsoidals are supplied with a certain size lens that determines the beam angle, normally five to fifty degrees. Variable focus instruments with two lenses are also available, allowing the user to manually adjust to the desired Focal Length . The most popular type of ellipsoidal light in modern theaters is the Electronic Theatre Controls ''Source Four'', which has a variety of special features including a rotating barrel, a slot to fit glass gobos, and a Dichroic Reflector . Other modern designs include the '' Lekolite '' and ''Altman Shakespeare'' series. SEE ALSO EXTERNAL LINKS |
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