| 摘要 |
<p>Provided are a zoom lens system used for a video camera and a digital still camera, compact and covering a range from the wide angle side to the tele side and having high image forming performance in the entire zoom range independent of the distance to an object, and an imaging device using the zoom lens system. The zoom lens system includes the following lens groups arranged in sequence from the object side in the listed order: a first lens group (GR1) having positive refraction power, a second lens group (GR2) having negative refractive power, a 3rd lens group (GR3) having positive refractive power, a 4th lens group (GR4) having positive refractive power, a 5th lens group (GR5) having weal refractive power (including refractive power = 0), and a 6th lens group (GR6) having negative refractive power. Magnification of the zoom lens is varied by varying the distance between each lens group and the next. The zoom lens system satisfies the expressions of (1), (2), and (3) below, where DW (i - j) is the distance between an i-th lens group and a j-th lens group at a wide angle end and DT (i - j) is the distance between the i-th lens group and the j-th lens group at a tele end, and in the zoom lens system, focusing is made by moving the 4th lens group (GR4) in the optical axis direction. (1) DW(1 - 2) < DT(1 - 2) (2) DW(2 - 3) > DT(2 - 3) (3) DW(5 - 6) > DT(5 - 6)</p> |
