The STAGE LIGHTING Guide

FOCUSING

Focusing is probably the most important part of the whole lighting operation. Not even the most sophisticated marvel of a microprocessor control desk can fill in that dark spot where the lights have not been properly overlapped. Nor can a hard edge be softened or a disturbing spill on to a border be shuttered off. Focusing involves tricky ladder work so that there is every incentive to get it right first time - although, inevitably, it will be necessary to get at the odd spotlight between rehearsals for a little fine adjustment.

Focusing in comfort

If you stand with your back to the light that you are focusing, (1) You will avoid being blinded (2) You will be able to see what the actor's light is doing to the scenery

Focusing with back to the light (A)

No clear shadow of head, therefore head is not lit.

Focusing with back to the light (B)

Clear shadow of head, therefore head is lit

Focusing with back to the light (C)

If the lighting designer is shorter than the actor, make an allowance - check by raising hand

What can we adjust?

ON ALL LIGHTS

Left/Right & Up/Down

ON FRESNEL and PC SPOTS

Bigger/Smaller

with optional Barndoor rough shaping (& control of spill)

ON PROFILE SPOTS

Round size by optional iris

Shape size by shutters

Texture by optional GOBO

Beam edge quality by lens differential movement of two lenses

Shape by shutters

The most difficult types of light are the basic Profile Spots since there is an interaction between shutters (or iris) and lens movement. Although adjusting the lens is principally a means of making the edge of the beam harder or softer, it will also change the size. Therefore it is usually necessary to adjust shutters and lens alternately to get the desired combination of size and edge quality

Controls on a Fresnel spot

FRESNEL and PC SPOT

Controls on a Fresnel spot

VARAIBLE ANGLE PROFILE SPOT

Controls on a fixed beam profile spot

FIXED ANGLE PROFILE SPOT

Most profiles have an adjustment whereby the light can be adjusted so that it is either smooth across the whole spread of the beam, or 'peaked' to be brighter in the middle with the amount of light falling off towards the edge. For most purposes it is easier to light with an even brightness across the beam and so it is recommended that anyone beginning to work with light should use an even beam until through experience they discover a need for a 'peaky' beam.

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