An optical apparatus is disclosed which can perform accurate focus control even when an image of an object at low contrast is picked up in high resolution. The optical apparatus includes a plurality of band-pass filters for different frequency bands and extracts a focus signal from the image signal through each of the band-pass filters, and a controller which performs focus control based on the extracted focus signal. In the focus control by the controller, the band-pass filters are selectively used to extract the focus signal depending on a resolution for recording the image signal.