A foot-candle (fc) measures illuminance, the light arriving at a surface. One foot-candle equals one lumen per square foot, or approximately 10.764 lux.
Converting readings
Multiply foot-candles by 10.764 to obtain lux. Divide lux by 10.764 to obtain foot-candles. For example, 100 fc is approximately 1,076 lux, and 1,000 lux is approximately 92.9 fc.
What changes when you change units
Changing a meter from lux to foot-candles only changes the displayed unit. It does not change the light level or the camera exposure. Keep the unit attached to every reading in a lighting plan so “100” cannot be mistaken for a different level.
Practical example
If a fixture chart lists 200 fc at a given distance and your meter displays lux, the comparable target is about 2,153 lux. Match the chart’s distance, optic, CCT and dimming setting before judging the result. A foot-candle reading alone does not specify an f-stop; camera settings and metering calibration also matter.
Related terms
Lux · Lumen · Inverse-Square Law