As visual perception varies logarithmically, it is helpful to have an appreciation of both
illuminance
In photometry (optics), photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate w ...
and
luminance by orders of magnitude.
Illuminance
To help compare different
orders of magnitude
An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic dis ...
, the following list describes various source of
lux, which is measured in
lumens per
square metre.
Luminance
This section lists examples of
luminances, measured in
candelas per square metre and grouped by
order of magnitude
An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic di ...
.
See also
*
Photometry (optics)
Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy (including light) in terms of absolute power. ...
*
Extraterrestrial sky
In astronomy, an extraterrestrial sky is a view of outer space from the surface of an astronomical body other than Earth.
The only extraterrestrial sky that has been directly observed and photographed by astronauts is that of the Moon. The sk ...
Notes and references
{{Orders of magnitude
Illuminance
In photometry (optics), photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate w ...
Photometry