1. An image sensor comprising: a pixel array in which focus detection pixels and imaging pixels are arranged in a matrix, wherein each of the focus detection pixels outputs a signal for focus detection with a phase difference detection method and an image signal and wherein each of the imaging pixels outputs an image signal and does not output a focus detection signal; and a controller that controls signal readout from the pixel array, wherein the focus detection pixels and the imaging pixels are arranged in a first pattern in a first type of pixel row in the pixel array, and the focus detection pixels and the imaging pixels are arranged in a second pattern in a second type of pixel row in the pixel array, and the controller performs readout control that differs between the first type of pixel row and the second type of pixel row.