Sidney F. Ray BSc, Msc, ASIS, FBIPP, FMPA, FRPS is Principal Lecturer in Photographic and Electronic Imaging Sciences at the University of Westminster. He is a well known photographic author whose publications include the highly acclaimed Applied Photographic Optics, now in its second edition. He has also written The Photographic Lens, edited the Photographic Pocket Book series and contributed to the Manual of Photography, now in its eighth edition. He has a lifetime of experience in photography and applied imaging and acts as an external examiner and advisor to many academic institutions and photographic associations.