JP2008139644A5 - - Google Patents

Claims (6)

In order from the object side to the image side, the first lens having a negative refractive power having a concave surface on the image side and a meniscus shape, the second lens having a positive refractive power having both lens surfaces convex, the third lens having both surfaces concave and positive, An optical system composed of a fourth lens having a refractive power of
When the distance between the first lens and the second lens is D2, the focal length of the entire system is f, the focal length of the first lens is f1, and the focal length of the second lens is f2.
0.3 <D2 / f <0.4
1.4 <| f1 / f2 | <2.7
An optical system characterized by satisfying the following conditions. When the focal length of the third lens is f3 and the focal length of the fourth lens is f4,
0.5 <| f3 / f4 | <0.85
The optical system according to claim 1, wherein the following condition is satisfied. When the radius of curvature of the image side lens surface of the first lens is R2, and the radius of curvature of the object side lens surface of the second lens is R3,
0.4 <R2 / R3 <1.0
The optical system according to claim 1, wherein the following condition is satisfied. When the curvature radii of the object-side and image-side lens surfaces of the second lens are R3 and R4,
0.2 <| R3 / R4 | <0.8
The optical system according to claim 1, wherein the following condition is satisfied. When the radius of curvature of the image side lens surface of the first lens is R2, and the radius of curvature of the image side lens surface of the third lens is R6,
0.35 <R2 / R6 <0.65
The optical system according to claim 1, wherein the following condition is satisfied.   An optical apparatus comprising: the optical system according to any one of claims 1 to 5; and an image sensor that receives an image formed by the optical system.