Patent ID: 7692874

Claim:
A wide-angle optical system, characterized by comprising, in order from its object side, a stop, a first lens having positive refracting power, a second lens having negative refracting power and a third lens that is an aspheric lens, wherein said third lens is configured such that as viewed in a lens section including an optical axis, a portion thereof near said optical axis is in a meniscus shape convex on an object side thereof, and an object side surface and an image side surface thereof at a peripheral site are in a meniscus shape convex on an image side thereof, with satisfaction of the following conditions (1-1) and (1-2) −0.40< f/f 3<0.15 (1-2) 0.30< hc 7/ hp 7<2.0 (1-2) where f is a focal length of the whole wide-angle optical system, and f 3 is a focal length of said third lens, and when Lm stands for a light ray passing through the center of said stop at an angle of 36° with said optical axis, and Pm 7 stands for a point at which Lm passes the image side surface of the third lens, hc 7 is a distance from Pm 7 to said optical axis, and hp 7 is a distance from a convex apex Pp 7 of the image side surface of said third lens to said optical axis.