To reduce power consumption in a solid-state image sensor that measures a time. The solid-state image sensor includes a count unit, a count control unit, a clock unit, and an estimation unit. The count unit counts the number of times a photon has been incident within a predetermined exposure period, and outputs a count value. The count control unit performs control to stop the count unit and performs a request of time information in a case where the count value has reached a predetermined value before the predetermined exposure period elapses. The clock unit measures a time and outputs the time information in response to the request. The estimation unit estimates the number of incident times of a photon within the predetermined exposure period on the basis of the output time information.