US Patent 7962020 Imaging apparatus

An imaging apparatus includes an imaging device, and an optical system configured to image light from an imaging subject on the imaging device. The optical system includes a group of lenses and an aperture diaphragm. When NP point is defined as a point where an extended linear component in an object space of a principal ray located in a Gauss region and selected from among principal rays passing through a center of the aperture diaphragm of the optical system crosses an optical axis of the optical system, D represents a diameter of a lens at the closest side to the imaging subject, and LN represents a distance from a lens surface of the lens at the closest side to the imaging subject to the NP point, a formula; 0≦LN≦D (1) is satisfied.