Lighting & Photometrics Calculator
Calculate light falloff using the inverse square law, convert Lux to Foot-Candles, and estimate required aperture f-stops.
Input Parameters
Manufacturer photometric rating (e.g. Aputure 600d = approx. 17,000 Lux @ 3m with reflector; Nanlux Evoke 1200 = approx. 65,000 Lux @ 3m).
Distance from the lighting fixture to your talent / subject.
Calculation Results
Calculated incident light intensity.
Imperial illuminance
At ISO 800 & 1/48s shutter
The Inverse Square Law and Exposure Photometrics
The Inverse Square Law states that the illuminance produced by a point source of light is inversely proportional to the square of the distance from the source. Doubling the distance from 2 meters to 4 meters reduces the light intensity to one quarter (1/4) of its original level (a 2-stop loss). Understanding this falloff is fundamental for gaffers designing lighting ratios between key, fill, and background lights.
Frequently Asked Questions
Q1. How does 1 Foot-Candle convert to Lux?
1 Foot-Candle (fc) equals exactly 10.764 Lux. As a fast on-set rule of thumb for ISO 800 at 24fps (1/48s), roughly 25 Foot-Candles (approx. 270 Lux) gives you an aperture of T/2.0.
Explore More Production Calculators
Tools designed for cinematographers, DITs, gaffers, and stage technicians.
Cinema Depth of Field Calculator
Precise depth of field, hyperfocal distance, near limit, and far limit calculations for professional digital cinema cameras, spherical primes, and anamorphic lenses.
Field of View (FoV) & Lens Angle Calculator
Calculate exact horizontal and diagonal angles of view (AOV) and physical framing dimensions for any sensor format and focal length.
Camera Recording Time & Media Calculator
Calculate storage capacity, recording runtime, and hourly data consumption across professional cinema codecs.
Timelapse & Slow Motion Shooting Calculator
Calculate frame counts, intervalometer shooting gaps, and playback runtimes for time manipulation cinematography.
Camera Battery Run Time & Power Calculator
Calculate total rig power draw (Watts) and battery endurance in hours and minutes with built-in safety margins.
Camera Jib & Crane Calculator
Calculate counterweight balance requirements, leverage ratios, and fulcrum pivot loads for film jibs and cranes.
Production Monitor & Display Viewing Distance
Calculate SMPTE, THX, and human visual acuity viewing distances for color grading suites, broadcast monitors, and video village setups.
LED Video Wall Dimension & Power Calculator
Calculate total pixel resolution, physical dimensions, surface area, and electrical power loads across pixel pitches.
Projector Lumens & Throw Distance Calculator
Calculate required ANSI Lumens output and optical throw distances based on screen size and ambient light conditions.
Need Professional Cinema Equipment in Greece?
BLK Cine Rentals provides ARRI Alexa 35, Sony Venice 2, Cooke / Master Primes, lighting, and camera cranes for international film productions.