Spotlight

A tight beam picks one thing out and lets the rest go. The pool of light is a statement about attention, and everybody in the audience knows they are being pointed at something.

It carries the theatre with it. A person who walks into a spot has been singled out, and a person who walks out of one has escaped.

A small source behind a lens or a snoot throws a narrow cone with a defined edge. The edge is the identifying feature, and a real spot can be focused from a hard line to a soft one.

Falloff outside the pool is steep, so the surround goes several stops down within a short distance. Aim the beam slightly across the subject rather than straight on, or the pool sits flat and looks pasted.

A visible pool on the floor or the wall sells it. Without a surface for the beam to land on, the audience sees a lit person and no spotlight.

Use it on a performance, an interrogation, a confession, or the moment a character is exposed in front of others.

Avoid it in a naturalistic scene with no source for it. A hard pool of light in a kitchen reads as an effect, and the audience starts looking for the lamp.

Cameo lighting is about the surround being black. A spotlight is about the beam being narrow and hard edged, and it can happen in a room that is otherwise lit.

The test is whether you can see where the light stops. A spotlight has a visible boundary. Cameo lighting simply runs out of subject.

The edge comes back soft and the shot becomes a general key. Say the pool of light has a hard edge, and name the surface it falls on.

The second failure is even spill across the whole frame. Ask for everything outside the beam to sit in darkness, and ban soft spill by name.