## What does an ellipsoidal reflector do?

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.

What is an ellipsoidal reflector often called?

The “ellipsoidal reflector spotlight,” or ERS, has been called by various names through the years. Theater professionals may refer to it as an “ellipse” or “ellipsoidal.” “Source Four” is a brand name, and that term is used, too. You may also hear long-time stagehands call it a “Leko,” pronounced LEE-koh.

What does a Fresnel do?

Fresnel lens, succession of concentric rings, each consisting of an element of a simple lens, assembled in proper relationship on a flat surface to provide a short focal length. The Fresnel lens is used particularly in lighthouses and searchlights to concentrate the light into a relatively narrow beam.

### What determines the beam angle on an ellipsoidal instrument?

Ellipsoidal are supplied with a certain size lens or lenses that determines the field angle, anywhere from five to ninety degrees. The field angle is the angle of the beam of light where it reaches 10% of the intensity of the center of the beam.

What is Fresnel lighting used for?

A Fresnel lantern (pronounced frəˈnɛl or fruh-nel) 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 of light, which is commonly used for back light and top light.

What are the properties of ellipsoid?

ellipsoid, closed surface of which all plane cross sections are either ellipses or circles. An ellipsoid is symmetrical about three mutually perpendicular axes that intersect at the centre. If a, b, and c are the principal semiaxes, the general equation of such an ellipsoid is x2/a2 + y2/b2 + z2/c2 = 1.

#### What type of reflector does a Fresnel use?

spherical reflector
Fresnels use a spherical reflector, with the filament of the lamp at the focus point of the reflector. The reflector effectively doubles the light output of the fixture, as all light that is emitted backwards into the reflector is reflected back through the filament of the lamp and out the front.

Why is Fresnel lens used?

What are the 4 controllable properties of a light?

Lighting for the stage involves manipulating the four major Controllable Qualities of light; Intensity, Color, Direction and Movement; to influence the four functions of stage lighting which are Mood, Selective Focus, Modeling and Visibility.