| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized zoom lens of high image quality having a variable power ratio of approximately 3 times to 5 times suitable for a video camera, a digital still camera or the like. SOLUTION: A zoom lens 1 consists of a first lens group GR1 having the positive refracting power, a second lens group GR2 having the negative refracting power, a third lens group GR3 having the positive refracting power, and a fourth lens group GR4 having the positive refracting power, successively arranged from the object side, and executes the zooming by moving the second and fourth lens groups. On this occasion, the third lens group consists of at least one lens having the positive refracting power on the object side, and at least one lens having the negative refracting power, through a stop IR, and a condition of 0.018<(Di-Do)/(Di.Le3)<0.04 is satisfied when Di is a diameter of incident light flux to the third lens group at a short focal length end, Do is a diameter of outgoing beam from the third lens group at the short focal length end, and Le3 is a length from a surface closest to the object side to a surface closest to an image, of the third lens group.
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