An image pickup apparatus, comprising: an image pickup unit including: a plurality of microlenses arrayed in a row direction and a column direction; and a pixel region including a plurality of unit pixels arrayed in the row direction and the column direction so as to correspond to the plurality of microlenses, respectively, the plurality of unit pixels each including a first photoelectric converter (201a, 601a) and a second photoelectric converter (201b, 601b), the image pickup unit being configured to employ at least: a first mode that is a mode in which a signal corresponding to charges generated in the first photoelectric converter and the second photoelectric converter is subjected to synthesis processing, and the signal subjected to the synthesis processing is read out; and a second mode that is a mode in which a signal corresponding to the charges generated in the first photoelectric converter is read out without the synthesis processing, characterized by a controller configured to read out, in the first mode, a first row positioned in a first region of the pixel region, and read out, in the second mode and a mode different from the second mode, a second row positioned in a second region of the pixel region, which is different from the first region, wherein the first row positioned in the first region is read out in the first mode during a first read-out period (1003, 1603), the second row positioned in the second region is read out in the second mode during a second read-out period (1001, 1601) different from the first read-out period, the second row positioned in the second region is read out in the mode different from the second mode during a third read-out period (1002, 1602) different from both of the first read-out period and the second read-out period, the first read-out period, the second read-out period, and the third read-out period have the same length when an image is acquired. an image pickup unit including: a plurality of microlenses arrayed in a row direction and a column direction; and a pixel region including a plurality of unit pixels arrayed in the row direction and the column direction so as to correspond to the plurality of microlenses, respectively, a plurality of microlenses arrayed in a row direction and a column direction; and a pixel region including a plurality of unit pixels arrayed in the row direction and the column direction so as to correspond to the plurality of microlenses, respectively, the plurality of unit pixels each including a first photoelectric converter (201a, 601a) and a second photoelectric converter (201b, 601b), the image pickup unit being configured to employ at least: a first mode that is a mode in which a signal corresponding to charges generated in the first photoelectric converter and the second photoelectric converter is subjected to synthesis processing, and the signal subjected to the synthesis processing is read out; and a second mode that is a mode in which a signal corresponding to the charges generated in the first photoelectric converter is read out without the synthesis processing, a first mode that is a mode in which a signal corresponding to charges generated in the first photoelectric converter and the second photoelectric converter is subjected to synthesis processing, and the signal subjected to the synthesis processing is read out; and a second mode that is a mode in which a signal corresponding to the charges generated in the first photoelectric converter is read out without the synthesis processing, characterized by a controller configured to read out, in the first mode, a first row positioned in a first region of the pixel region, and read out, in the second mode and a mode different from the second mode, a second row positioned in a second region of the pixel region, which is different from the first region, wherein the first row positioned in the first region is read out in the first mode during a first read-out period (1003, 1603), the second row positioned in the second region is read out in the second mode during a second read-out period (1001, 1601) different from the first read-out period, the second row positioned in the second region is read out in the mode different from the second mode during a third read-out period (1002, 1602) different from both of the first read-out period and the second read-out period, the first read-out period, the second read-out period, and the third read-out period have the same length when an image is acquired.