A light field camera (also called a plenoptic camera) is an imaging device that creates pictures that can be refocused after they are taken.
The light field is the totality of photons traveling in all directions throughout all points in space in a given area. Light field photography accesses all the information available about light rays interacting with objects in a scene. In optics, the plenoptic function provides a means of identifying a 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. A company called Lytro released the first commercially available light field camera in early 2012.
The Lytro camera's light sensor consists of a conventional digital camera CMOS (complementary metal-oxide semiconductor) working in conjunction with a micro-lens array containing thousands of tiny lenses to capture all the light field data. The miniature lenses each divide CMOS pixels into multiple areas to accommodate views of an object from various angles. The light sensor records information about the angle of light, in addition to the information about color, intensity and position recorded by conventional cameras. The light field data is stored along with the image data and software, either on the camera or online, allows the images to be refocused to display relevant information for the area selected.
Robert Scoble checks out the Lytro camera: