The
light field is a
vector function that describes the amount of
light flowing in every direction through every point in space. The direction of each ray is given by the 5D plenoptic function, and the magnitude of each ray is given by the
radiance.
Michael Faraday was the first to propose (in an
1846 lecture entitled "Thoughts on Ray Vibrations") that light should be interpreted as a field, much like the magnetic fields on which he had been working for several years. The phrase
light field was coined by Alexander Gershun in a classic paper on the radiometric properties of light in three-dimensional space (1936).