BS 4793:1972

Covers zoom lenses, variable focal length lenses and single focal length lenses, used in either black-and-white or colour reproduction systems. These recommendations adopt the optical transfer function (OTF), or more specifically its modulus, the modulation transfer function (MTF), as the method of assessment and specification of image quality. Covers the performance of lenses as a complete optical unit but does not deal with the performance of individual component parts.