An optical apparatus includes a lens part including a first imaging portion forming a first image of an object and a second imaging portion forming a second image of the object, and a filter part including a filter arranged on at least one of optical axes of the first and second imaging portions and configured to make properties of light for forming the first image and light for forming second image different from each other. The first and second images correspond to a common field stop. F numbers of the first and second imaging portions are different from each other.