Noun
the luminous flux incident on a unit area
Source: WordNetBoth the PRC and the required illuminance vary from species to species and lower light levels are required to reset the clocks in nocturnal rodents than in humans. Source: Internet
Use of absolute aperture diameter The aperture diameter is normally given in terms of the f-number because all lenses set to the same f-number give approximately the same image illuminance (Ray 2002, 130), simplifying exposure settings. Source: Internet
What gets directly measured by a light meter is incident light on a sensor of finite area, i.e. illuminance in lm/m 2 (lux). Source: Internet