The light field is the totality of photons (light particles) traveling in all directions throughout all points in space in a given area. Specifics within the light field can be determined according to the plenoptic function, which can identify any given point where light arrives in a scene through five dimensions (5D): three to determine the position of the point and two more to identify the angle by which the light arrives at that point.
The concept of the light field has had a long development. In the fifteenth century, in his manuscripts on painting, Leonardo da Vinci wrote about the behaviour of photons -- which he called “radiant pyramids” --within a given scene. In an 1846 presentation, Michael Faraday (for whom both the faraday and the farad are named) suggested that light should be considered to manifest a field, similarly to magnetic fields. The first person to use the term light field was Alexander Gershun, in a 1936 paper on the properties of light within three-dimensional (3D) space.
Various researchers have studied the potential of light field photography over the years. Lytro released the first commercial light field camera in 2012. Because a light field camera captures all the information required to recreate the view from any visible perspective, an image taken with it can be refocused after the picture is taken.