Integral imaging is an autostereoscopic and multiscopic three-dimensional imaging technique that captures and reproduces a light field by using a two-dimensional array of microlenses, sometimes called a fly's-eye lens, normally without the aid of a larger overall objective or viewing lens. In capture mode, each microlens allows an image of the subject as seen from the viewpoint of that lens's location to be acquired. In reproduction mode, each microlens allows each observing eye to see only the area of the associated micro-image containing the portion of the subject that would have been visible through that space from that eye's location. The optical geometry can perhaps be visualized more easily by substituting pinholes for the microlenses, as has actually been done for some demonstrations and special applications.