Patent ID: 6992720

Claim:
An optical apparatus including at least any one of a plurality of image pickup apparatuses which have different forms of image pickup devices and a plurality of image pickup modes, and a lens apparatus interchangeably mounted on the one image pickup apparatus, the one image pickup apparatus and the lens apparatus having contacts for performing transmission between the one image pickup apparatus and the lens apparatus, the optical apparatus comprising: an image pickup optical unit which is included in the lens apparatus; a light quantity adjustment unit inserted in an optical path of the image pickup optical unit, said light quantity adjustment unit changing an aperture diameter to change a light quantity; and a controller for controlling a change of the aperture diameter by said light quantity adjustment unit, said controller obtaining information concerning the form of the image pickup device and information concerning the image pickup mode from the image pickup apparatus by transmission via the contacts, wherein said controller changes a set value of said light quantity adjustment unit for a minimum aperture diameter of the aperture diameter in accordance with the information concerning the form of the image pickup device of the image pickup apparatus that is obtained by the transmission when the information concerning the image pickup mode obtained by the transmission represents a preset image pickup mode out of the plurality of image pickup modes.