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Foot-lambert, luminance
A foot-lambert or footlambert (fL, sometimes fl) is a unit of measurement of luminance in U.S. customary units. A footlambert equals 1 / π candela per square foot, or 3.4262591 candelas per square meter (nits). The luminance of a perfect lambertian diffuse reflecting surface in footlamberts is equal to the incident illuminance in foot-candles. For real diffuse reflectors, the ratio of luminance to illuminance in these units is roughly equal to the reflectance of the surface.
1 fL
is equal to
3.43 cd/m²
Candela per square metre (cd/m²)
3.43
Kilocandela per square metre (kcd/m²)
3.43×10-3
Candela per square centimetre (cd/cm²)
3.43×10-4
Candela per square foot (cd/ft²)
0.32
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1
-
1.08×10-3
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3.43
-
3.43×10-4