| 摘要 |
The invention provides a zooming lens system which covers a wide-angle zone, has a zooming ratio of approximately 3 or higher, and is well corrected for various aberrations. This system comprises, in order from the object side, a first lens unit I having positive refracting power, a second lens unit II having negative refracting power, a third lens unit III having positive refracting power, a fourth lens unit IV having positive refracting power and a fifth lens unit V having positive refracting power, with at least said first, third, fourth and fifth lens units being moved toward the object side for zooming from the wide-angle end to the telephoto end, and conforms to the following conditions: -0.8<f2/fW<-0.5 (1) -0.7<fT12/fT<-0.3 (2) Here f2 is the focal length of the second lens unit, fW is the focal length of the entire system at the wide-angle end, fT12 is the composite focal length of the first and second lens units at the telephoto end, and fT is the focal length of the entire system at the telephoto end.
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