This International Standard gives general guidance for the construction and use of equipment for measurement of the optical transfer function (OTF) of imaging systems. This International Standard specifies important factors that can influence the measurement of the OTF, and gives general rules for equipment performance requirements and environmental controls. It specifies important precautions that should be taken to ensure accurate measurements and correction factors to be applied to the collected data. The OTF measuring equipment described in this International Standard is restricted to that which analyses the radiation distribution in the image plane of the optical imaging system under test. Interferometer-based instruments are outside the scope of this International Standard.