A solid-state image sensor produces an image including plural sub-images, which are rapidly read out and outputted via output circuits. The image sensor has its imaging surface divided into corresponding plural sub-areas producing image data, which is transferred by the horizontal transfer path in both left and right directions and outputted from the output circuits, whose amplifier characteristics are determined as follows. Optical black (OB) data from an OB area on the imaging surface is transferred in the left direction by the horizontal transfer path and outputted from one output circuit as total OB data. OB data is transferred by the horizontal transfer path in both left and right direction and outputted from the output circuits as left and right OB data. An output circuit characteristics determiner uses the total, and left and right OB data to determine the amplifier characteristics of the output circuits.