Patent ID: 8988784
Filing Date: 2015-03-24
Classification: G02B

Abstract:
1. A zoom lens, substantially consisting of: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group having negative refractive power, which are arranged in this order from an object side of the zoom lens, wherein when varying magnification from a wide angle end to a telephoto end, a distance between the first lens group and the second lens group is consistently increased, a distance between the second lens group and the third lens group is consistently decreased, a distance between the third lens group and the fourth lens group is consistently decreased, and a distance between the fourth lens group and the fifth lens group is changed, while all of the lens groups are moved with respect to an image formation position, wherein when moving a point of focus from an infinity side to a near side to achieve focus, only the fifth lens group is moved from the object side to the image side, wherein the fifth lens group has at least one lens having negative refractive power and at least one lens having positive refractive power, and wherein the following formula (Ca) is satisfied: β