Patent ID: 6721105
Filing Date: 2004-04-13
Classification: G02B

Abstract:
A zoom lens system comprising, in order from an object:a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having positive refractive power; when the state of lens group positions varies from a wide-angle end state to a telephoto end state, a separation between the first lens group and the second lens group increasing; a separation between the second lens group and the third lens group decreasing; a separation between the third lens group and the fourth lens group varying; a separation between the fourth lens group and the fifth lens group increasing; and the third lens group and the fourth lens group moving to the object side; and wherein the following conditional expressions are satisfied; â€ƒ4.51/FW<8.00.82/FW|<1.8 2.33/FW<4.5 2.04/FW<5.2 0.234W-D34T)/FW<1.0 where FW denotes the focal length of the zoom lens system in the wide-angle end state, F1 denotes the focal length of the first lens group, F2 denotes the focal length of the second lens group, F3 denotes the focal length of the third lens group, F4 denotes the focal length of the fourth lens group, D34W denotes the separation between the third lens group and the fourth lens group in the wide-angle end state, and D34T denotes the separation between the third lens group and the fourth lens group in the telephoto end state.