Patent ID: 8982482
Filing Date: 2015-03-17
Classification: G02B

Abstract:
1. A wide-angle optical system, comprising, in order from an object side thereof, a first lens group having negative refracting power and a second lens group having positive refracting power, wherein: the second lens group consists, in order from the object side, a widest separation among axial air separation except a back focus provides an axial space for receiving the aperture stop; the optical system is divided into the first lens group and the second lens group with a second widest air separation as a boundary; the first lens group comprises a meniscus lens having an object-side surface convex to the object side, and a paraxial radius of curvature of the object-side surface is a positive value; and focusing is implemented by moving the whole optical system, with satisfaction of the following Condition (1): where n d is a d-line refractive index of the first double-convex lens.