Foot-lambert (fL)
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.
- 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
- Foot-lambert (fL)1
- Lambert (L)1.08×10⁻³
- Nit3.43
- Stilb3.43×10⁻⁴