This International Standard de­fines terms relating to the optical transfer function and indicates, where pertinent, the mathematical relationships between those terms. It also defines important parameters that should be speci­fied in connection with optical transfer function testing. Table 1 lists the notation and units for the major parameters consid­ered in this International Standard and to be used in ISO 9335 and ISO 9336. The terms and parameters de­fined in this International Standard apply to all measurements of the optical transfer function for optical, electro-optical and other imaging systems.