| 摘要 |
A three-group zoom lens having lens groups, in order from the photographic object side, of negative, positive, and positive refractive power. The zoom lens is specially designed for use in a still or video camera employing a CCD array positioned at a fixed photographic image plane. Zooming is primarily performed by moving the two lens groups nearest the photographic object side, and focusing is primarily performed by adjusting the position of the lens group nearest the photographic image side. By satisfying certain conditional expressions a distance from the exit pupil to the photographic image plane is maintained to prevent shading, a back focus length sufficient to accommodate a filter component is provided, and a compact zoom lens of high quality is obtained.
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