In 1946, P.M. DUFFIEUX proposed the application of the transfer function(T.F.)concept to the optics field. A few years later, H.H. HOPKINS, W.H. STEEL, SHADE, LINFOOT and MARECHAL completed the theoretical framework started by their predecessor. This subject has since inspired much work which has been based more on "experimentation and measurement" than on the theoretical aspect. Restricting ourselves in the context of this meeting to the french contribution, we find that during the 1960-1970 period, three laboratories have devoted a considerable part of their research work to this area. In Besancon, Professor VIENOT and his team became interested in this problem very early, developing a method of 910aining the T.F. from the analogue spectral analysis of the point spread response of an optical system . More recently, in Professor FRACON's Paris laboratory, a method for measuq;lg the T.F. of an optical system by holographic recording the wave surface was proposed by Miss MAY. On our part, since 1962, our team at the INSTITUT d'OPTIQUE has been studyg and perfecting a method for measuring the Modulation Transfer Function (M.T.F.) of optical system , which hasiwulted in the development of a measurement instrument, the ACOFAM, manufactured by the MATRA Company.