[en] The purpose of this work is to explore the parameters influencing the image quality and patient dose by means of subjective and semi-objective methods. Exposures and measurements were performed on two film-screen mammography systems - Mammomat 2 (Siemens, Germany) named in this text Unit 1, and Affinity (Lorad, USA), named Unit 2. Unit 1 has only semi automatic exposure control (AEC) system - the operator is selecting tube voltage. Unit 2 has a full AEC system. Both units have Mo/Mo anod/filter combinations. Barts dosimetric and imaging phantom for mammography was used for image quality assessment Exposure conditions of the Barts phantom and the results from the subjective, semi-objective assessment of image quality and calculation of ESAK on Unit 1 and Unit 2 are shown. Similar results for the both units but for different kV and AEC setting '1.5' are also presented