Profile Spot

Overview

The Profile Spot (German: Profilscheinwerfer, also known in English as Ellipsoidal Reflector Spotlight, or ERS, or Profile Spotlight) is a lens spotlight that produces a sharply defined, shapeable beam of light. Its hallmark is the sharp, precisely definable edge of the light beam: the beam edge can be precisely aligned with objects, people, or set edges – hence the name "Profile" (contour). Functionally, the device operates like an optical projector.

In theater and event lighting, the term is standard; on film and TV sets, the same type of fixture is usually referred to by the common brand names Source Four (ETC) or Leko, or generally as an ellipsoidal spotlight. Profile spots are available in classic incandescent/halogen versions as well as modern LED versions.

Construction and Function

The optics combine an ellipsoidal reflector with a lens barrel. The lamp is positioned at the first focal point of the reflector; the collected light is focused onto the second focal point, where the beam-shaping elements are located, and then projected through the lens(es) – typically one or two plano-convex lenses. By moving the lens barrel, the beam can be focused from hard (sharp edge) to soft (diffuse edge).

Several elements are used for beam shaping:

• Shutters: usually four adjustable metal blades at the focal point, used to cut the round beam into straight edges, rectangles, or angled shapes – ideal for precisely cutting off the edges of the image.
• Gobo Slot: a holder for metal or glass gobos, used to project patterns, textures (e.g., window mullions, leaves, "breakup") or logos sharply.
• Iris: stepless reduction of the round light beam.

The beam angle is determined by interchangeable lens barrels or zoom optics; common fixed focal lengths and zoom ranges are specified by the respective manufacturer.

Use on Set

Profile spots are used wherever light needs to be precisely limited and shaped, rather than illuminating a broad area:

• Highlighting individual people or objects with a clearly defined light spot.
• Cleanly cutting off light at image boundaries, set edges, or backgrounds to avoid spill (stray light).
• Projecting patterns and textures via gobos, for example, for broken shadow light ("breakup") or window/blind effects.
• Logo or text projection in studio and event applications.

Distinction: A Profile Spot is a *fixed* fixture and should not be confused with a Follow Spot, which manually tracks a moving person.