Systems and methods for providing illumination suitable for imaging devices such as laser projection systems, wherein the illumination pattern is adjustable by modifying one or more characteristics of a controlled angle diffuser. In one embodiment, a highly collimated (e.g., laser light) beam is passed through a holographic diffuser to create a well defined cone angle for the light emanating from each point on the diffuser. This light is focused into an illumination image that is controlled by the prescription of the diffuser. In one embodiment, the diffuser can be positioned to alternately place different regions having different prescriptions in the optical path corresponding to the illumination image. In one embodiment, the diffuser can be continually moved to eliminate speckling and "worminess" in the illumination image.