A photo-electric conversion device is provided with a light receiving array and circuits serving to scan the same. A light receiving device separate from the array but adjacent thereto is used as a part of a control device for controlling the accumulation time of the array. A saturation detection circuit may be arranged to receive the output of the array and to vary the accumulation time by a suitable factor when array saturation occurs. The conversion device may also be provided with means for compensating for leakage currents in the conversion block, so as to facilitate higher linearity at low illumination intensities.