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Zoom lens

Image Number 11 for United States Patent #6646815.

A zoom lens, comprises: three lens groups including a first lens group having a negative refracting power, a second lens group having a positive refracting power and a third lens group having a positive refracting power arranged serially in this order from the object side. The second lens group comprises a positive lens, a cemented lens including a positive lens and a negative lens and one lens arranged serially in this order from the object side. The following conditional expression is satisfied;where f.sub.2 represents a focal length of the second lens group and f.sub.w represents a focal length of the total optical system at a wide-angle end.

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