Patent ID: 7990624

Claim:
A zoom lens comprising: a first lens group of positive refracting power; a second lens group of negative refracting power; a third lens group of positive refracting power; and a fourth lens group of positive refracting power, wherein said first to fourth lens groups are provided in this order from an object side to an image side, wherein, during zooming from a wide-angle end to a telephoto end, at least said first lens group moves, wherein said third lens group includes, in an order from the object side to the image side, a first lens sub-group of positive refracting power and a second lens sub-group of negative refracting power, wherein said second lens sub-group of said third lens group is comprised of a single negative lens, wherein said first lens sub-group of said third lens group is moved in a direction having a perpendicular component relative to an optical axis to correct image blur to be produced when said zoom lens vibrates, and wherein, when a focal length of said first lens group is denoted by f 1 and a the focal length of the whole system at the wide-angle end is denoted by fw, a conditional expression 10.0 <f 1 /fw< 20.0 is satisfied, wherein, when a focal length of said first lens sub-group of said third lens group is denoted by f 3 a and a focal length of said fourth lens group is denoted by f 4 , a conditional expression 0.3<f 3 a /f 4 <0.8 is satisfied.