| 摘要 |
The invention provides a compact yet high-zoom-ratio zoom lens system for use with lens shutter cameras, which is well corrected for aberrations albeit being made up of a small number of lenses. The zoom lens comprises a first lens group G1 of positive refracting power, a second lens group G2 of positive refractive power and a third lens group G3 of negative refracting power. The lens groups move for zooming from the wide angle side to the telephoto side, with a separation between the first and second lens groups becoming wide and a separation between the second and third lens groups becoming narrow. At least one lens group has a diffractive surface therein, and satisfies 1.8< beta T/ beta W<4.0 where beta T and beta W are transverse magnifications of the lens group having a diffractive surface at the wide-angle end and the telephoto end of the lens system.
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