Patent ID: 8670187

Claim:
A zoom lens comprising sequentially from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, and a third lens group having a positive refractive power, the third lens group being moved along an optical axis from an image side toward the object side to zoom from a wide angle edge to a telephoto edge and the second lens group being moved along the optical axis from the object side toward the image side to zoom and correct variation of an image plane position, wherein the first lens group includes a negative lens and a positive lens, the second lens group includes sequentially from the object side, two negative lenses and one positive lens, the third lens group includes sequentially from the object side, a front group that has a positive overall refractive power and includes a positive aspheric lens, a middle group that has a negative overall refractive power and includes one cemented lens formed by a positive lens and a negative lens, and a rear group having a positive refractive power, and the zoom lens satisfies a conditional expression (1) 0.7≦fw/f3≦1.0 and a conditional expression (2) −1.0f3/f2≦−0.5, where fw represents a focal length of the entire optical system, at the wide angle edge; f2 represents a focal length of the second lens group; and f3 represents a focal length of the third lens group.