1. An optical apparatus comprising: an imaging optical system including a correction lens, which corrects an image blur, a zoom lens for changing a focal length, and a focus lens, which performs focus adjustment; a focal length detection unit configured to detect the focal length of an imaging optical system; an object distance detection unit configured to detect an object distance; a shake detection unit configured to detect a shake amount; a walking shooting determination unit configured to determine whether or not a user of the optical apparatus is walking based on the shake amount detected by the shake detection unit; a sensitivity generation unit configured to generate sensitivity, which is a ratio of a moving amount of an object image on an image sensing plane to a moving amount of the correction lens, based on a determination result by the walking shooting determination unit, the focal length, and the object distance; a correction amount calculation unit configured to calculate a correction amount based on the shake amount and the sensitivity; and a control unit configured to drive the imaging optical system to correct the image blur based on the correction amount, wherein the sensitivity generation unit generates the sensitivity by limiting at least one of the object distance or the focal length, or a range of the sensitivity when the walking shooting determination unit determines that the user of the optical apparatus is walking.