Patent ID: 7535657

Claim:
A zoom lens system comprising at least: a first lens group GR 1 having a positive refractive power; a second lens group GR 2 having a negative refractive power; a third lens group GR 3 having a positive refractive power; a fourth lens group GR 4 having a negative refractive power; a fifth lens group GR 5 having a positive refractive power; and a sixth lens group GR 6 having a negative refractive power, arranged sequentially from the object side, zoom ratio being varied by changing the distance between the adjacent lens groups, the distance, taken as DW(i-j), between the i- and j-th lens groups at the wide angle end during at-infinity imaging and that, taken as DT(i-j), between the i- and j-th lens groups at the telephoto end during at-infinity imaging meeting the following conditions (1), (2), (3), (4) and (5) DW(1-2)<DT(1-2) (1) DW(2-3)>DT(2-3) (2) DW(3-4)>DT(3-4) (3) DW(4-5)<DT(4-5) (4) DW(5-6)<DT(5-6) (5), and focusing being made by moving the fourth lens group GR 4 axially of the lenses.