Patent ID: 7009782

Claim:
An imaging optical system for forming an image of an object, comprising: a first lens unit located at a most object-side position; and one or more second lens units interposed between the first lens unit and the image, at least one of the second lens units being moved along an optical axis, wherein the first lens unit includes, in order from an object side: at least one lens with negative refracting power; a deformable mirror; and at least one lens with positive refracting power, wherein focusing is performed by deformation of the deformable mirror, and wherein one of the following conditions is satisfied: 0.1< d 1 / fw< 10.0 0.1< d 2 / fw< 10.0 where d 1 is a distance from an object-side lens surface adjacent to the deformable mirror to the deformable mirror, d 2 is a distance from the deformable mirror to an image-side lens surface adjacent to the deformable mirror, and fw is a focal length of the imaging optical system at a wide-angle position.