Ellipsoidal reflector spot (abbreviated to ERS, or colloquially ellipsoidal or ellipse) is the name for a type of stage lighting instrument, named for the ellipsoidal reflector used to collect and direct the light through a barrel that contains a lens or lens train. The optics of an ERS instrument are roughly similar to those of a 35 mm slide projector.
There are many types of ERS that are designed for the myriad applications found in the entertainment industry. ERS instruments come in all shapes and sizes. Each particular model of ERS has its own set of characteristics. Generally, ERS instruments are the most varied and utilized type of stage lighting instrument. ERS may also be referred to as Profile Spotlights (especially in Europe) because the beam can be shaped to the profile of an object.
Ellipsoidal reflectors are used for their strong, well-defined light and their versatility. Leko and Source Four are brand names which are often, but inaccurately, used to refer to any sort of ellipsoidal.
Characteristics of a typical ellipsoidal lighting unit include:
The lamps are loaded from the rear (in most cases), and either mounted axially, or radially with the base either up or down (the orientation is important when mounting the instrument as using the light upside down will shorten lamp life) at a 45-degree angle or sometimes at a 90-degree angle. The filament of the lamp is at one focal point of the ellipsoidal reflector and the gate with the shutters and gobo are at the other focal point.
Ellipsoidals are supplied with a certain size lens or lenses that determines the field angle, anywhere from five to ninety degrees. Field angle is the angle of the beam of light where it reaches 10% of the intensity of the center of the beam. Most manufacturers now use field angle to indicate the fixture's spread typically in this series (5°, 10°, 19°, 26°, 36°, 50°, 75°, 90°). Older fixtures are described by the width of the lens x focal length of the instrument. For example, a 6x9 ellipsoidal would have a 6" diameter lens and a focal length of 9". 6x9 Instruments have a field angle of approximately 37°. 6x12 instruments have a field angle of approximately 27°. As the field angle narrows, the instrument can be used further from the stage. Variable focus (zoom) instruments with two lenses that move in and out from the lamp housing are also available, allowing the user to manually adjust to the desired focal length within a certain range. Ellipsoidals can be used for any job but their primary function is to illuminate a specific proximity. They are the common use for spotlights as they can give a small sharp circle. It has an ellipsoidal reflector behind the lamp to reflect the light in the direction required. They have brackets on the end to attach gels and barn doors. Barn doors do the same as the shutters but give a softer edge. [1]
The Electronic Theatre Controls Source Four, released in 1992, updated the traditional ERS design. The company took advantage of advances in lamp and reflector technology to increase luminous output with less wattage. The Source Four name comes from the improved lamp design utilizing four filament elements.
Other improvements included the use of a single lens in most lens trains, making the unit lighter and more efficient in regards to light output, and a rotating barrel containing lens tube assembly, shutters, and accessory slot to allow increased precision in use of the shutters and/or more easily registering gobos.
Since the release of the Source Four, other lighting manufacturers have since revised their products to compete in the market share alongside the ETC. The Selecon Pacific, an L-shaped ERS, has an irregular shape due to an integrated dichroic cold mirror, which effectively splits the visible wavelengths of the light beam from the infrared, allowing the heat to be drawn off by a heat sink and away from the instrument. This keeps the beam of the fixture cool allowing for the use of plastic gobos. The beam also improves shutter, gobo and color gel life, and can improve the temperature on stage. [2] Altman Lighting released their Shakespeare line of units in 1994 as a response to the Source Four. One improvement over the Source Four is a wider range of adjustment in regards to rotation of the barrel assembly. The patents for some components in this unit have been licensed from ETC.
In 2004 ADB introduced WARP Profile - In this ellipsoidal profile spot conventional shutters have been replaced by four integrated blades controlled by a series of rings, each with 360⁰ endless rotation capability. Focus and Zoom settings are also controlled by a set of dedicated rings. The ring controls leave the exterior of the WARP spotlight with no protruding handles or levers. The design of the WARP allows the standard trunion arms to be replaced with a motorised yoke. This yoke links also into the ring controls providing automation of all other functions—focus and zoom, shutter insertion / rotation and gobo rotation. The motorised unit is without any forced ventilation (fans) and completely silent, making the unit ideal for acoustic critical applications (TV studios, concert halls et al.)
Most recently, Philips Strand Lighting released their Lekolite ERS. Improvements in this fixture include improved optics, 360-degree barrel rotation, a specialized yoke design allowing for rapid tool-free short yoking, a quick change lamp and improved heat dissipation technology and design integration.
In 2011 the LED technology has also finally reached the ERS applications, with several major lighting manufacturer companies worldwide introducing an energy saving, no maintenance, modern version of the standard ETC Source Four. On April 6, 2011, the Italian manufacturer Coemar launched Reflection LEDko at PLASA (the ProLight+Sound Association fair, one of the main tradeshows of the lighting industry, held annually in Frankfurt, Germany), a development which could lead to an average power consumption saving of 85 percent.
The film industry is built upon many technologies and techniques, drawing upon photography, stagecraft, music, and many other disciplines. Following is an index of specific terminology applicable thereto.
Stage lighting is the craft of lighting as it applies to the production of theater, dance, opera, and other performance arts. Several different types of stage lighting instruments are used in this discipline. In addition to basic lighting, modern stage lighting can also include special effects, such as lasers and fog machines. People who work on stage lighting are commonly referred to as lighting technicians or lighting designers.
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
A flashlight or electric torch, usually shortened to torch, is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the early 2000s. A typical flashlight consists of the light source mounted in a reflector, a transparent cover to protect the light source and reflector, a battery, and a switch, all enclosed in a case.
A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, headlamp is the term for the device itself and headlight is the term for the beam of light produced and distributed by the device.
A Klieg light is an intense carbon arc lamp especially used in filmmaking. It is named after inventor John Kliegl and his brother Anton Kliegl. Klieg lights usually have a Fresnel lens with a spherical reflector or an ellipsoidal reflector with a lens train containing two plano-convex lenses or a single step lens.
A gobo is an object placed inside or in front of a light source to control the shape of the emitted light and its shadow.
In stage lighting, an ellipsoidal reflector floodlight, better known as a scoop, is a large, simple lighting fixture with a dome-like reflector, large high-wattage lamp and no lens. It consists almost entirely of a lamp in the center of a big curved metal dome that acts as a reflector. The result is a wide, soft-edged pool of light good for general lighting. However, since scoop lights do not have a mechanism for cutting down the size of their beam, they are rarely used for more specific lighting needs.
A parabolic aluminized reflector lamp is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights.
Intelligent lighting refers to lighting that has automated or mechanical abilities beyond those of conventional, stationary illumination. Although the most advanced intelligent lights can produce extraordinarily complex effects, the intelligence lies with the human lighting designer, control system programmer, or the lighting operator, rather than the fixture itself. For this reason, intelligent lighting (ILS) is also known as automated lighting, moving lights, moving heads, or simply movers.
A Fresnel lantern is a common lantern used in theatre that employs a Fresnel lens to wash light over an area of the stage. The lens produces a wider, soft-edged beam than a spotlight or key light, and is commonly used for back light and top light.
Stage lighting instruments are used in stage lighting to illuminate theatrical productions, concerts, and other performances taking place in live performance venues. They are also used to light television studios and sound stages.
Portrait photography, or portraiture, is a type of photography aimed toward capturing the personality of a person or group of people by using effective lighting, backdrops, and poses. A portrait photograph may be artistic or clinical. Frequently, portraits are commissioned for special occasions, such as weddings, school events, or commercial purposes. Portraits can serve many purposes, ranging from usage on a personal web site to display in the lobby of a business.
A beam projector is a lenseless stage lighting instrument with very little beam spread. It uses two reflectors. The primary reflector is a parabolic reflector and the secondary reflector is a spherical reflector. The parabolic reflector organizes the light into nearly parallel beams, and the spherical reflector is placed in front of the lamp to reflect light from the lamp back to the parabolic reflector, which reduces spill. The result is an intense shaft of light that cannot be easily controlled or modified. Beam projectors are often used to create a godspot effect. The beam projector no longer is used to the extent that it once was, as newer fixtures and PAR lamps have created easier ways to produce the effect. A similar effect can be produced using ETC Source Four PAR fixtures with a clear lens. A snoot/top hat can be added to control spill.
The SeaChanger Color Engine is an electro-mechanical device that is used to control light color in entertainment-industry lighting applications. The unit employs four overlapped color filter wheels, inserted into a light beam near its source, to produce colored light. This is in contrast to color scrollers, which insert color filter ribbons into a light beam. The color engine, which was released by Ocean Thin Films in 2005, is designed to fit into the Source Four lighting instrument made by Electronic Theatre Controls.
LED stage lighting is a stage lighting technology that uses light-emitting diodes (LEDs) as a light source. LED instruments are an alternative to traditional stage lights which use halogen lamp or high-intensity discharge lamps. Like other LED instruments, they have high light output with lower power consumption.
Vari-Lite is a brand of automated, variable-colour stage lighting systems. Their intelligent lighting fixtures are commonly used in theatre, concerts, television, film and corporate events.
The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints that include cost, weight and materials. For many other optical devices such as telescopes, microscopes and theodolites where the visual image is observed but often not recorded the design can often be significantly simpler than is the case in a camera where every image is captured on film or image sensor and can be subject to detailed scrutiny at a later stage. Photographic lenses also include those used in enlargers and projectors.
Articles related to the field of motion pictures include:
Stage lighting accessories are components manufactured for conventional (non-automated) stage lighting instruments. Most conventional fixtures are designed to accept a number of different accessories designed to assist in the modification of the output. These accessories are intended to either provide relatively common functionality not originally provided in a fixture, or to extend the versatility of a lighting instrument by introducing features. Other accessories have been designed to overcome limitations or difficulties some fixtures present in specific applications.