Patent ID: 8385002

Claim:
A zoom lens comprising: a first lens group having a positive refractive power, a second lens group having a negative refractive power, and an additional lens grouping having a positive refractive power, which are sequentially arranged from an object side, wherein the additional lens grouping comprises a third lens group having a positive refractive power, wherein the third lens group is shifted towards an image side to perform focusing at a minimum distance, and wherein when an effective focal length of the third lens group refers to f 3 [mm], and an effective focal length of the additional lens grouping at the telephoto position refers to f rt [mm], and an effective focal length of the second lens group refers to f 2 [mm], the zoom lens satisfies the following formulae: Formulae 0.1< f 3 /f rt <2.0, 1.5<| f 3 /f 2 |<4.0.