Patent ID: 8649108

Claim:
A zoom lens comprising: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a negative refractive power and comprised of a single negative lens; a fourth lens group having a positive refractive power; a fifth lens group having a positive refractive power, the first to fifth groups being arranged along an optical axis in order from an object side; and an aperture stop disposed between the third lens group and the fourth lens group, wherein: the fifth lens group consists of a positive lens and a negative lens; when zooming from a wide angle end to a telephoto end, the zoom lens is moved so that an interval between the first and second lens groups increases, an interval between the second and third lens groups varies, an interval between the third and fourth lens groups decreases, and the third lens group focuses; and the second lens group is arranged to have a focal length to satisfy the following condition: 0.95 <|f 2/√( fw*ft )|<4.0 where f2 is a focal length of the second lens group, fw is a focal length of the entire zoom lens at the wide angle end and ft is a focal length of the entire zoom lens at the telephoto end.