Patent ID: 7110186

Claim:
A zoom lens comprising: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; a fourth lens group having a positive refracting power; and a fifth lens group having a negative refracting power from an object side in this order, wherein a zooming operation is carried out by moving the second lens group and the fourth lens group, wherein; said first lens group includes; a foreside lens group having a negative refracting power; an optical element for folding an optical path; and a backside lens group having a positive refracting power from the object side in this order, and wherein; a condition of 1.0<β 5 <1.9 is satisfied, provided that an imaging power of the fifth lens group where an object distance is at infinity is β 5 ; the zooming operation from a wide-end side to a tele-end side is carried out by moving the second lens group from the object side to the image plane side and by moving the fourth lens group from the image plane side to the object side; and a condition of 0.5<|dZ 2 /dZ 4 |<1.2 is satisfied, provided that a stroke from a short focal length end to a long focal length end is dZ 2 , and a stroke of the fourth lens group from the short focal length end to the long focal length end where an object distance is at infinity is dZ 4 .