Patent ID: 7304803

Claim:
A zoom lens unit, comprising: a first lens group having a positive refracting power; a second lens group having a negative refracting power; and a subsequent lens group comprising one or more lens groups and having a positive refracting power as a whole, said one or more lens groups comprising a third lens group, the first lens group, the second lens group and the subsequent lens group being arranged in this order from an object side to an image side, an aperture stop disposed between the second lens group and the third lens group, wherein when changing a magnification from a wide angle end to a telephoto end, a distance between the first lens group and the second lens group increases, while a distance between the second lens group and the subsequent lens group decreases, wherein a lens construction including the first and the second lens groups satisfies the condition: 1.0 <r i /r i+1 <5.0 (1), in which r i and r i+1 are curvature radii of lens surfaces S i and S i+1 in the lens construction, respectively, the lens surfaces S i and S i+1 being“i”th and “i+1”th lens surfaces, respectively, counted from the object side, and wherein a reflectivity-reducing treatment adapted to reduce intensity of a ghost image is performed on each lens surface forming at least one of pairs of lens surfaces satisfying the condition (1).