Patent ID: 8619373

Claim:
A zoom lens comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, the third lens group including, in order from the object side, a first positive lens, a cemented lens constructed by in order from the object side a second positive lens cemented with a negative lens, and a negative meniscus lens, and the following conditional expressions being satisfied: r3R<0 âˆ’2.00<( r 3 R+r 3 F )/( r 3 Râˆ’r 3 F )<1.00 6.00< f 1/ (âˆ’ f 2)<7.80 where r 3 F denotes a radius of curvature of an image side lens surface of the cemented lens in the third lens group, r 3 R denotes a radius of curvature of an object side lens surface of the negative meniscus lens in the third lens group, f 1 denotes a focal length of the first lens group, and f 2 denotes a focal length of the second lens group.