Catadioptric optical system and image-pickup apparatus having the same

摘要

A catadioptric optical system includes a first imaging optical system including a catadioptric part configured to condense a light flux from an object and to form an intermediate image of the object, and a second imaging optical system including a dioptric part configured to form an image of the intermediate image on an image surface. The light flux from the object passes through the light transmission part of the first optical element, the negative lens, the backside reflection part of the second optical element, the negative lens, the backside reflection part of the first optical element, the negative lens, and the light transmission part of the second optical element, in this order, and is emitted to the second imaging optical system. An Abbe number of a material of the negative lens is larger than that of a material of the second optical element.