A solid-state image sensor is provided. The solid-state image sensor includes a semiconductor substrate having photoelectric conversion elements. The photoelectric conversion elements form an N×N pixel array, where N is a positive integer larger than or equal to 3. The solid-state image sensor also includes a modulation layer disposed above the photoelectric conversion elements. The solid-state image sensor further includes a light-adjusting structure disposed on the modulation layer and corresponding to the N×N pixel array. The N×N pixel array includes a first pixel region having at least one first pixel. The N×N pixel array also includes a second pixel region adjacent to the first pixel region in a first direction and in a second direction different from the first direction and having second pixels. The aperture ratio of the first pixel and the aperture ratio of the second pixel are different.