Valgusvoog arvestab silma tundlikkust, kaaludes võimsust igal lainepikkusel heledusfunktsiooniga, mis esindab silma reaktsiooni erinevatele lainepikkustele.
In photometry, luminous flux or luminous power is the measure of the perceived power of light.
The luminous flux accounts for the sensitivity of the eye by weighting the power at each wavelength with the luminosity function, which represents the eye's response to different wavelengths.