Spotlights Stage lighting instrument

1 spotlights

1.1 fresnel lantern
1.2 ellipsoidal reflector spotlight

1.2.1 field angle


1.3 beam projector
1.4 followspot

spotlights

a spotlight lighting instrument used in theater create pool of light on stage. there many different types of spotlights break down 3 general areas:

fresnel lanterns or fresnels (us) small fixtures giving soft-edged spot or pool of light. name comes distinctive ridged fresnel lens used on front.
profile spots (uk) or ellipsoidal reflector spotlights (us) tend longer fixtures containing convex lenses , having gate @ focal point enables insertion of gobos or irises shape beam of light. give hard-edged beam associated in public mind spotlights . large versions operated technician followspot follow performers on stage. term profile spot used in uk refers focussing spotlight may, or may not use ellipsoidal reflector design, design not common in uk until 1970s , many uk , european manufacturers have still adopt design instead preferring twin pc lens design.
pebble convex lanterns (or pcs ) similar fresnels, use plano-convex lens pebbled effect on planar (flat) side, resulting in less spill outside main beam. used more in europe north america.

fresnel lantern

fresnel lens open show stepped lens. there no lamp in instrument.



left-snoot right-barn door

a fresnel lantern (uk), or fresnel (us), employs fresnel lens wash light on area of stage. lens named after french physicist augustin-jean fresnel, , consequently pronounced silent s . distinctive lens has stepped appearance instead of full or smooth appearance of used in other lanterns. resulting beam of light wide , soft-edged, creating soft shadows, , commonly used light, top light, , side light. method of controlling spread of light use either top hat (also referred snoot), limits light coming out, or barn door, flaps work though shutters on ers (shown on right). these methods limit light output , keep excess light spilling eyes of audience members or not desired.

fresnels use spherical reflector, lamp @ focus point. lamp , reflector remain fixed unit inside housing, , moved forward , focus light. accomplished using slider on bottom or side of lantern, or using worm track. @ tight focus, lanterns least efficient, least light can escape housing. therefore, fresnels not tight focus on small areas. used @ medium distances stage area lighting.

in 1999, etc introduced new lighting fixture, source 4 parnel, combined design of par fixture of fresnel. fixture more versatile, allowing flood or softer spot.

ellipsoidal reflector spotlight

etc source 4 ers.

the ellipsoidal reflector spotlight (ers), known profile (after ability project silhouette or profile of put in gate) (uk) , découpe (french), abundant instrument type in theatrical use. flexibility of ers allows fulfill bulk of lighting roles in theater. known profile spotlight (in europe) or brand names, source 4 (a popular lantern etc) , 2 leko (short lekolite, strand lighting).

the major components of ers light casing in internal parts mounted, ellipsoidal reflector located in of casing, lamp mounted position filament @ rear focal point of ellipsoid, dual plano-convex lens (two plano-convex lenses facing each other in barrel), , @ front, gel frame hold color gel. light lamp efficiently gathered ellipsoidal reflector , sent forward through gate, shutters , lens system.

a diagram of selecon performance lighting pacific zoomspot.

ers or profile lanterns have many useful features. 1 of useful metal shutters @ focal plane of lens shape beam of light. original shape of beam round, use of shutters 1 can limit beam avoid obstacles or parts of set should not illuminated in specific look. feature gate, in focal plane, sliding in gobos (also known templates or deckles). these have patterns cut them, stencil. these patterns projected onto stage. iris can inserted in position make beam smaller in diameter, reducing light cast without sharp edges of shutters. ers instruments etc, altman, selecon, , variety of others have interchangeable lens tubes (or barrels) can both create sharp or soft beam alter beam spread. barrel sizes can range narrow, long distance 5- or 10-degree spot broad , short-distance 50- or 90-degree. first 90-degree profile lantern developed selecon performance lighting part of pacific range of products. since introduction many other manufacturers have introduced own 90-degree barrels. ers instruments allow many different lens tubes used same body. makes them more versatile, since venue can purchase varying degrees of barrels without buying many instruments. many manufacturers produce zoom lenses offer ability change beam angle. zoom ranges have poorer optical quality making them difficult use in sharp focus.

field angle

the field angle of instrument angle of beam of light reaches 10% of intensity of center of beam. manufacturers use field angle indicate spread fixture has. however, older fixtures described width of lens x focal length of instrument. example, 6x9 ellipsoidal have 6 lens , focal length of 9 (creating approximately 37° beam angle). nomenclature used because traditionally larger lens directly equated more light output. no longer true, manufacturers identify fixtures beam angle , light output. field angle narrows, instrument can either used further stage create similarly-sized beam closer, larger instrument, or can used same distance create smaller beam.

beam projector

a beam projector lensless instrument little beam spread. uses 2 reflectors. primary reflector parabolic reflector , secondary reflector spherical reflector. parabolic reflector directs light parallel beams, , spherical reflector placed in front of lamp reflect light lamp parabolic reflector, reduces spill. result intense shaft of light cannot controlled or modified. beam projector no longer used extent once was, newer fixtures , par lamps have created easier ways produce effect.

followspot

followspot

the followspot (also called spotlight, trackspot, lime (uk), or dome) lighting instrument moved during performance operator or dmx control provide emphasis or illumination , follow specific performer moving around stage. follow spots commonly used in musical theater , opera highlight stars of performance, may used in dramas well. used in sports venues, many other applications.

these lighting instruments come in variety of sizes light sources ranging low power incandescent light bulbs powerful xenon arc lamps. carbon arc lamp spots common until 1990s, using arc between carbon rods light source. these follow spots required special installations include high volume ventilation due hazardous fumes produced carbon arc. current generation, xenon, has extremely high internal pressure in lamp , has own safety concerns.

followspots contain variety of operator-controlled optical mechanisms. may include mechanical shutters, allow light doused without turning off lamp, lenses control , focus beam width, , internal color gels, in color magazine.