1. An exposure measurement system comprising; a plurality of photoelectric converting elements each for converting a portion of a light beam into an electrical signal corresponding to a portion of the light beam, scanning means electrically coupled with said elements for sensing the outputs of the elements one after another, digital converting means coupled to said scanning means for converting the sensed outputs of the photoelectric converting elements into digital signals, a processing device coupled to said digital converting means for processing the output of the photoelectric converting elements converted into digital values by means of the digital converting means in accordance with a predetermined estimation function so as to determine an exposure value. and control means for controlling the processing operation of said processing device, said control means being operable for causing the processing device to select optional elements whose outputs are to be utilized for the determination of the exposure value.