Patent ID: 8643954

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 positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, which are sequentially arranged from an object side, wherein when an effective focal length of the third lens group is f 3 [mm], an effective focal length of the third to fifth lens groups at the telephoto position is f rt [mm], and an effective focal length of the second lens group is f 2 [mm], the zoom lens satisfies the additional formulae: 0.1 <f 3 /f rt <2.0, 1.5 <|f 3 /f 2 |<4.0 Formulae.