The paper describes an instrument for measuring the transfer function of optical systems. The test object used is a very narrow slit. The fine-line image produced by optical image formation is measured without a microscope objective, whereupon the optical transfer function is computed with the aid of an analog computer. The highest frequency to be measured is 750 cycles/mm. The instrument is suited for any scale of reproduction and allows measurement of the fine-line image, the optical transfer function, the knifeedge image, and vignetting.
Paul Kuttner, "An Instrument for Determining the Transfer Function of Optical Systems," Appl. Opt. 7, 1029-1033 (1968)