An imaging apparatus includes a pixel array, a first adder, a second adder, a first A/D converter circuit, and a second A/D converter circuit. The pixel array includes a plurality of pairs of first pixels and second pixels. Each pair of the first pixel and the second pixel receives a light flux passing through a photography optical system by pupil-dividing the light flux. The first adder adds outputs of the first pixels and outputs of the second pixels. The second adder generates a first output by adding the outputs of the first pixels and generates a second output by adding the outputs of the second pixels. The first A/D converter circuit converts an output of the first adder to a digital signal. The second A/D converter circuit converts an output of the second adder to a digital signal.