Lux
From The Glossary of Digital Photography
A unit used in measuring illumination. Also called a candle-meter or meter-candle. A lux is equal to one lumen per square meter, which is equivalent to the amount of light on a surface one meter away from a single candle. A single candle produces one candela. Moonlight produces light of approximately one lux and sunlight on an average day varies from 32,000 lux to over 100,000 lux. See also candle; candela (cd)
