Pronounced "fren-el."
SU theatre only has Altman fresnels and they are rarely used as the inventory is very limited.
SU theatre only has Altman fresnels and they are rarely used as the inventory is very limited.
Fixture Overview
The fresnel fixture is named thus because of the lens. It is a variation of a plano-convex lens that has had portions of the convex side removed, resulting in a thinner lens that absorbs less heat and weighs less without affecting the optics of the light. The plano side of the lens is dimpled to soften the light and remove any distortion from the rings. This lens was invented by Augustin-Jean Fresnel for use in lighthouses.
Fresnel fixture is a wash fixture with a semi-harsh beam, but undefined edges and produces a circular beam. Beam diameter can be adjusted by moving a sled closer or further from the lens. Fresnel fixtures are referred to by their lens diameter, such as 6-inch or 8-inch.
When "spotted down," the fixture has a central "hot spot" but quickly loses intensity towards the edges.
When "flooded," the fixture has a smooth wash of light.
Fresnel fixture is a wash fixture with a semi-harsh beam, but undefined edges and produces a circular beam. Beam diameter can be adjusted by moving a sled closer or further from the lens. Fresnel fixtures are referred to by their lens diameter, such as 6-inch or 8-inch.
When "spotted down," the fixture has a central "hot spot" but quickly loses intensity towards the edges.
When "flooded," the fixture has a smooth wash of light.
Fixture Parts
Yoke - U-shaped bracket that supports and attaches the fixture to a pipe/batten via the c-clamp. Allows for panning and tilting of the fixture during focus.
Lens release knob - allows access to the interior of the fixture. Fresnel lens - a variation of the plano-convex lens that has the portions of the convex surface removed. A dimpled texture on the plano surfaces adds a diffusing effect that masks the concentric rings found on its front surface. Yoke locking knob - loosen to adjust the tilt of a fixture. Lens retaining ring - holds the fresnel lens in place on the fixture. Color frame holder - slot to place color frame and other accessories on the fixture. Stage pin plug - used to plug the fixture into the circuit. Flat connector often referred to as pin connector or two-pin and ground connector. |
Spherical reflector - the reflector of the fresnel fixture is spherical and has a single focal point. (The reflector in this image is damaged)
Lamp - Fresnel fixtures are typically either 500 W or 1000 W fixtures. Altman fixtures use BVT or BVV lamps, which have a prefocus base. Source Four fixtures use a HPL. Socket - this is where the lamp is placed. The prefocus lamp has a particular way in which it fits and then turns to place it in the correct alignment with the reflector. Sled - the spherical reflector and lamp are mounted in place and distance from each other on the sled. The sled moves closer and further to the lens, adjusting the beam spread of the fixture. Closer to the lens = flood focus Further from the lens = spot focus. |
Inkie (3" Fresnel)
Yoke - U-shaped bracket that supports and attaches the fixture to a pipe/batten via the c-clamp. Allows for panning and tilting of the fixture during focus.
Sled control screw - (spot/flood adjusting knob) allows for the moving of the sled closer or further from the lens. May also be located on the under side of the fixture or on the side. Color frame holder - slot to place color frame and other accessories on the fixture. Fresnel lens - a variation of the plano-convex lens that has the portions of the convex surface removed. A dimpled texture on the plano surfaces adds a diffusing effect that masks the concentric rings found on its front surface. Stage pin plug - used to plug the fixture into the circuit. Flat connector often referred to as pin connector or two-pin and ground connector. Access door bolt - screw bolt that allows access to the interior of the fixture. |
Access door - allows for access to the interior of the fixture. Should be closed before fixture is plugged in.
Spherical reflector - the reflector of the fresnel fixture is spherical and has a single focal point. Fresnel lens - a variation of the plano-convex lens that has the portions of the convex surface removed. A dimpled texture on the plano surfaces adds a diffusing effect that masks the concentric rings found on its front surface. Lamp - inkies typically use a 100 Watt lamp. (ANSI code ESR) Sled - the spherical reflector and lamp are mounted in place and distance from each other on the sled. The sled moves closer and further to the lens, adjusting the beam spread of the fixture. Closer to the lens = flood focus Further from the lens = spot focus. |
Copyright Caleb Stroman 2023
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