1. An imaging apparatus comprising: an optical system including a focus lens; an imaging unit operable to capture a subject image formed by the optical system to generate image data; a driver operable to drive the focus lens along an optical axis of the optical system; and an autofocus adjusting unit operable to adjust a subject image formed on the imaging unit to be in focus by evaluating the image data generated by the imaging unit and by controlling the driver to drive the focus lens; wherein when adjusting the subject image to be in focus anew after previously adjusting the subject image to be in focus, the autofocus adjusting unit estimates a focus position and controls the driver to drive the focus lens according to a driving method used for evaluating the image data generated by the imaging unit, and wherein different driving methods are used for different results of the estimation.