Disclosed are optical systems and methods of producing obliquity corrected light beams, for example, holographic recording and retrieval systems that utilize an obliquity corrected reference beam. One method includes directing a light beam reflected from a prism mirror to a reference plane with an angle of incidence to the reference plane, wherein the prism mirror varies the width of the light beam according to the angle of incidence to the reference plane. The optical system may include a holographic data storage system and the reference plane may be associated with a holographic storage medium.