An imaging device comprises a lens barrel including an optical system that collects light from a predetermined viewing area and that defines an optical axis; an imaging unit that receives the light collected by the optical system and generates image data, the image data defining a main image that includes a determined sub area; a ring-shaped operation ring that is provided on an outer circumference of the lens barrel and that is manually rotatable about the optical axis of the optical system; and an area change unit that changes at least one of (A) a size of the determined sub area, or (B) a position of the determined sub area, responsive to a manual operation of the operation ring.