An optical apparatus includes an image sensor that includes a focus detecting pixel and an image pickup pixel, a first focus detector configured to provide a focus detection based upon a phase difference between the pair of image signals detected by the focus detecting pixel of the image sensor, a second focus detector configured to provide a focus detection based upon a contrast value based upon an output of the image pickup pixel of the image sensor, and a controller configured to provide autofocus utilizing the first focus detector when a focus detection precision of the first focus detector is equal to or higher than a first value and an image magnification variation amount calculated from a wobbling amount of the image pickup optical system used for the second focus detector is equal to or higher than a second value.