Patent ID: 7362509

Claim:
A zoom lens comprising, in sequence from an object side to an image plane side: a first lens group having an overall negative refractive power, and a second lens group having an overall positive refractive power; wherein a zoom factor is changed from a wide-angle end to a telescopic end by moving said second lens group from said image plane side to said object side; wherein focal adjustment is performed by moving said first lens group to correct changes in said image plane accompanied by changes in said zoom factor; wherein said first lens group comprises, in sequence from said object side: a first lens having a negative refractive power, and a second lens having a positive refractive power; and wherein said second lens group comprises, in sequence from said object side: a third lens having a positive refractive power, a fourth lens, having a meniscus shape, a convex surface facing the object side, adjacent the third lens and a positive refractive power, a fifth lens, having is a meniscus shape, a convex surface facing the object side, and a negative refractive power, said fourth lens and said fifth lens being bonded and having an overall negative refractive power, and a sixth lens, biconvex, adjacent the fifth lens having a positive refractive power.