Patent ID: 9507169
Filing Date: 2016-11-29
CPC Classification: G02B

Claim Text:
1. A zoom lens including a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having negative refracting power and a fifth lens group having negative refracting power in order from an object side; wherein a surface of the fifth lens group disposed closest to the object side is concave; wherein the lens groups move in magnification change from a wide angle end to a telephoto end such that a gap between the first lens group and the second lens group increases and a gap between the second lens group and the third lens group decreases; a negative lens group disposed closer to an image plane side than a diaphragm among all lens groups is set as a focusing lens group, and the focusing lens group moves toward the image plane side in focusing from infinity to a close object; the zoom lens satisfies conditional expression (1); and the focus lens group is composed of a single lens block of a meniscus shape having a concave surface at image plane side, and satisfies conditional expression (2) below: where β4T: Lateral magnification in telephoto end of fourth lens group β5T: Lateral magnification in telephoto end of fifth lens group where ra4: Curvature radius of object side surface of focus lens group rb4: Curvature radius of image plane side surface of focus lens group.