A hologram is a 2D diffractive optical element which stores information from 3D objects. Contrary to general belief, however, the stored information is only a view of the object from a limited angular window and not the whole information contained in the object. Moreover, optically recorded holograms, as well as conventional computer generated ones, do not exploit the storage capacity of the medium in an efficient way. This paper describes procedures for optimal storage and outlines some applications in optical signal processing and storing 3D light distributions.