Patent ID: 7586683
Filing Date: 2009-09-08
Classification: G02B

Abstract:
1. A zoom lens comprising: a first lens group having a positive refracting power and being fixed with respect to an image plane: a second lens group having a negative refracting power and being movable along an optical axis to vary a power; a third lens aroup being fixed with respect to the image plane; a fourth lens group being fixed with respect to the image plane; and a fifth lens group having a positive refracting power and being movable along an optical axis; wherein said first, second, third, fourth and fifth lens groups are disposed in this order from an object side; wherein said third lens group and said fourth lens group compose a combination of a lens group havinn a positive refracting power and a lens group having a negative refracting power; wherein one of said third and fourth lens group is vertically movable with respect to the optical axis; and wherein the one of said third and fourth lens groups that is vertically movable with respect to the optical axis is composed of two lenses comprising one lens having a positive refracting power and one lens having a negative refracting power each being disposed separately from the object side in this order and each having sag amounts which are equal in the object side and in the image side.