Patent ID: 7256945

Claim:
A zoom lens comprising: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having negative refractive power; which are arranged in order from an object side, said zoom lens being configured to perform zooming by moving said second lens group and said fourth lens group; wherein said first lens group includes a front lens group having negative refractive power, an optical member refracting a light path, and a rear lens group having positive refractive power, which are arranged in order from the object side, wherein said fourth lens group includes one single lens, and wherein if image forming power of said fifth lens group at an object distance of infinity is set to be β5, the following conditional formula is satisfied: 1.0<β5<1.8 and wherein zooming from the short focal distance side to the long focal distance side is performed by moving said second lens group from the object side to the image surface side and moving said fourth lens group from the image surface side to the object side, and wherein if a stroke of said second lens group from a short focal distance end to a long focal distance end is set to be dZ2, and a stroke of said fourth lens group from the short focal distance end to the long focal distance end at the object distance of infinity is set to be dZ4, the following conditional formula is satisfied: 0.6<| dZ 2 /dZ 4|<2.0.