An image pickup apparatus has a plurality of pixels each of which includes first and second photoelectric converters and is arranged in a matrix and connected to a column output line, a reading unit configured to perform a first reading operation that reads a signal of the first photoelectric converter to the column output line and a second reading operation that reads a signal obtained by mixing the signals of the first and second photoelectric converters to the column output line, a column circuit configured to be connected to the column output line, and a control unit configured to save power in at least some of the column circuits not used during the first reading operation from among the column circuits used in the second reading operation, during the first reading operation.