THEA 332: Lighting and Sound Design
Lighting Instruments and Photometrics

Photometry Calculator a web-based photometrics calculator

Photometrics Data for Selected Instruments

 Instrument Type Lamp Wattage Beam Angle In Degrees Conversion Factors* Diameter Foot Candles Fresnel Spot 3" Spot 150 16 0.28 6,500 Flood 58 1.11 1,600 6" Spot 500 16 0.28 75,000 Flood 52 0.98 12,000 8" Spot 1000 11 0.19 100,000 Flood 48 0.88 12,000 Instrument Type Lamp Wattage Beam Angle In Degrees Conversion Factors* Diameter Foot Candles Ellipsoidal Reflector Spotlight (ERS) Strand 50° 1000 53 0.92 46,000 Strand 40° 1000 38 0.62 90,000 Strand 30° 1000 30 0.5 121,000 Strand 20° 1000 20 0.35 184,000 Source 4 50° 750 50 0.92 41,471 Source 4 36° 750 36 0.61 98,553 Source 4 26° 750 26 0.45 182,301 Source 4 19° 750 19 0.32 260,363 Source 4 10° 750 10 0.19 783,310 Altman 4.5 x 6.5 750 55 1.04 38,000 Altman 6 x 12 750 26 0.46 114,000 Instrument Type Lamp Wattage Beam Angle In Degrees Conversion Factors* Diameter Foot Candles Par 64 Spotlights WFL Long Axis 1000 71 1.43 40,000 Short Axis 45 0.82 MFL Long Axis 1000 44 0.8 125,000 Short Axis 21 0.37 NSP Long Axis 1000 26 0.46 330,000 Short Axis 14 0.24 VNSP Long Axis 1000 24 0.42 400,000 Short Axis 10 0.17 Instrument Type Lamp Wattage Beam Angle In Degrees Conversion Factors* Diameter Foot Candles Automated/Special VL 2500 Spot Spot 700 Arc 18.5 0.33 320,000 Flood 42 0.77 52,000 VL 1000 TSD Spot 1000 19.5 0.34 151,300 Flood 37 0.67 44,400 *Special flood 70 1.4 21,400 * To calculate beam diameter at any distance multiply distance by the conversion factor for diameter. To calculate Peek Illumination at any distance divide conversion factor for Foot Candles by the distance squared.

Specifications at Given Throw Distances

 Instrument Type 10 feet 15 feet 20 feet 30 feet 40 feet 50 feet 60 feet F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. Fresnel Spot 3" Spot 65 2.8 29 4.2 - - - - - - - - - - Flood 16 11.1 - - - - - - - - - - - - 6" Spot - - 333 4.2 188 5.6 83 8.4 47 11.2 30 14 21 16.8 Flood 120 9.8 53 14.7 30 19.6 - - - - - - - - 8" Spot - - - - - - 111 5.7 63 7.6 40 9.5 28 11.4 Flood 120 8.8 53 13.2 30 17.6 13 26.4 - - - - - - Instrument Type 10 feet 15 feet 20 feet 30 feet 40 feet 50 feet 60 feet F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. Ellipsoidal Reflector Spotlight (ERS) Strand 50° 460 9.2 204 13.8 115 18.4 54 27.6 - - - - - - Strand 40° 900 6.2 400 9.3 225 12.4 100 18.6 56 24.8 - - - - Strand 30° 1210 5 538 7.5 303 10 134 15 76 20 48 25 - - Strand 20° - - 818 5.2 460 7 204 10.5 115 14 74 17.5 51 21 Source 4 50° 415 9.2 184 13.8 103 18.4 46 27.6 - - - - - - Source 4 36° 986 6.1 438 9.15 246 12.2 109 18.3 62 24.4 - - - - Source 4 26° 1823 4.5 810 6.75 456 9 203 13.5 114 18 73 22.5 - - Source 4 19° - - 1157 4.8 651 6.4 289 9.6 163 12.8 104 16 72 19.2 Source 4 10° - - - - 1958 3.8 870 5.7 490 7.6 313 9.5 218 11.4 Altman 4.5 x 6.5 380 10.4 169 15.6 95 20.8 42 31.2 - - - - - - Altman 6 x 12 1140 4.6 507 6.9 285 9.2 127 13.9 71 18.5 46 23.1 - - Instrument Type 10 feet 15 feet 20 feet 30 feet 40 feet 50 feet 60 feet F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. Par 64 Spotlights WFL Long Axis 400 14.3 178 21.5 100 28.6 44 42.9 - - - Short Axis 8.2 12.3 16.4 24.6 - - - MFL Long Axis 1250 8 556 12 313 16 139 24 78 32 - - Short Axis 3.7 5.5 7.4 11.1 14.8 - - NSP Long Axis - - 1467 6.9 825 9.2 367 13.8 206 18.4 132 23 91 27.6 Short Axis - 3.6 4.8 7.2 9.6 12 14.4 VNSP Long Axis - - - - 1000 8.4 444 12.6 250 16.8 160 21 111 25.2 Short Axis - - 3.4 5.1 6.8 8.5 10.2 Instrument Type 10 feet 15 feet 20 feet 30 feet 40 feet 50 feet 60 feet F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. F.C. DIA. Automated/Special VL 2500 Spot Spot 3200 3.3 1422 4.95 800 6.6 356 9.9 200 13.2 128 16.5 89 19.8 Flood 520 7.7 231 11.6 130 15.4 58 23.1 32.5 30.8 20.8 38.5 14.4 46.2 VL 1000 TSD Spot 1513 3.4 672 5.1 378 6.8 168 10.2 95 13.6 61 17 42 20.4 Flood 444 6.7 197 10.1 111 13.4 49 20.1 28 26.8 18 33.5 12 40.2 SNAPS *Special flood 214 14 95 21 53 28 - - - - - - - -

Matthew A. Knewtson, Professor of Theatre
Western Michigan University