Patent ID: 7477456
Filing Date: 2009-01-13
Classification: G02B

Abstract:
1. A zoom lens comprising in the order from an object: (a) a first lens group having a negative refractive power, including at least one negative lens and one positive lens, wherein a negative plastic lens having one or more aspherical surfaces is arranged on a side closest to the object; (b) a second lens group having positive refractive power, including a first positive lens, a second positive lens and a negative lens in the order from the object; and (c) a third lens group, wherein each lens group is moved in a direction of an optical axis of the zoom lens to vary power thereof, and the following expressions are satisfied: where f 1 represents a focal length of the first lens group, f 1 a represents a focal length of the negative plastic lens arranged closest to the object, and fw represents a focal length at a wide-angle end of an entire zoom lens.