How many Foot-candles or Lux are needed for church or theater stage lighting?

Standard drama theater typically aims for 35 to 50 Foot-candles (380 to 540 Lux). Churches and broadcast stages with high-definition video streaming require 60 to 90 Foot-candles (650 to 1,000 Lux) on performers' faces to avoid camera sensor grain and noise.

How do I convert Foot-candles to Lux?

1 Foot-candle (FC) is equal to 10.764 Lux. For example, 50 Foot-candles equals approximately 538 Lux.

How much should stage lighting beams overlap for wash lighting?

Adjacent light fixtures should overlap by approximately 20% to 25% of their beam diameter (typically placing the edge of one beam at the center of the adjacent beam's field angle) to eliminate dark shadows between actor zones.

Free Stage Lighting Throw Distance & Beam Angle Calculator

💡 Fixture Optics & Rigging Geometry

Standard Theatrical Fixture Angle

Beam Angle (Degrees 50% cutoff)

Field Angle (Degrees 10% cutoff) Visible beam edge spill

Throw Distance (Feet) Distance from lens to actor/stage

Fixture Luminous Output

📊 Beam Coverage & Stage Illuminance

Beam Diameter Spread 16.2 Feet 4.95 meters circular footprint

Stage Illuminance 58 FC 624 Lux at stage center

Field Angle Diameter (Total Spill): 19.2 Feet (5.85 m)

Beam Pool Surface Area: 207 sq.ft (19.3 m²)

Beam Multiplication Factor: 0.65x Throw Distance

Recommended Overlap Spacing: 13.0 ft between adjacent fixtures

✅ Live Camera & Theater Ready: 58 Foot-candles (624 Lux) provides crisp facial key lighting for HD broadcasting and theatrical performances.

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The Trigonometry of Stage Lighting Beams

A theatrical light fixture emits a conical beam of light. The circular footprint diameter (D) on the stage floor is calculated directly from the fixture's beam angle ( heta) and throw distance (T):

Beam Diameter = 2 × Throw_Distance × tan(θ / 2)

The term (2 imes an( heta / 2)) is known in theatrical lighting design as the Beam Multiplication Factor. For a standard 36° ellipsoidal lens, the factor is approximately (0.65). If your lighting electric pipe is 20 feet away, the beam footprint will be (20 imes 0.65 = 13) feet wide.

Beam Angle vs Field Angle

Beam Angle (50% intensity): The inner cone where illuminance is at least 50% of the center peak intensity. This is the "active punchy" light.
Field Angle (10% intensity): The outer boundary where light drops down to 10% of peak intensity. Beyond the field angle, the beam drops into darkness.

The Inverse Square Law in Lighting

Illuminance (measured in Foot-candles or Lux) obeys the Inverse Square Law: doubling your throw distance cuts the brightness on stage by 75% (leaving only 1/4 the original light level)! To maintain even face illumination on moving actors, adjacent fixtures must be spaced so their beam angles overlap by at least 20% to 25%.