| 摘要 |
In five-constituent lens groups, the fourth lens group from the object side is made as a positive lens. This fourth lens group is moved in order to correct zooming and focusing, while predetermined conditional expressions are satisfied, thereby realizing a zoom lens which can attain a wide angle and a high zoom ratio while favorably correcting various kinds of aberration. This zoom lens has five groups respectively composed of positive, negative, positive, positive, and positive lens groups. At the time of zooming, the first, third, and fifth lens groups G1, G3, and G5 are made stationary, while the second and fourth lens groups G2 and G4 are made movable. As the second lens group G2 is moved in the optical axis direction, the focal length of the whole system is changed. As the fourth lens group G4 is moved in the optical axis direction, the fluctuation in imaging position is corrected and the change in the imaging position due to change in object distance is corrected. This zoom lens satisfies the following conditional expressions:-0.5<f2/(fwxft)+E,fra 1/2+EE <-0.2, 1.1<f3/(fwxft)+E,fra 1/2+EE <1.4, 0.4<f3/f1<0.7, 6.0<f5/f37.0
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