a plurality of pixels, the pixels each including a photoelectric conversion portion that outputs an electric signal produced in accordance with amount of incident light and converted natural-logarithmically and a lead-out path by way of which the electric signal output from the photoelectric conversion portion is fed to an output signal line, the photoelectric conversion portion comprising:

a photosensitive element having a first electrode to which a direct-current voltage is applied and a second electrode;

a first switch having one contact connected to the second electrode of the photosensitive element;

a first transistor having a first electrode connected to another contact of the first switch, a second electrode, and a control electrode;

a second transistor having a first electrode to which a direct-current voltage is applied, a second electrode from which an electric signal is output, and a control electrode connected to the first electrode of the first transistor; and

a second switch connected between the first electrode and control electrode of the first transistor; and

a controller that makes the individual pixels perform image sensing by turning on the first and second switches and that detects variations in sensitivity of the individual pixels by turning off the first and second switches and varying a voltage fed to the control electrode and second electrode of the first transistor,

wherein the pixels each further include a capacitor having one end connected to the control electrode of the first transistor, and

wherein the controller applies different voltages to another end of the capacitor between when making the individual pixels perform image sensing and when detecting variations in sensitivity of the individual pixels.