Patent ID: 9720216
Date: 2017-08-01
CPC Classifications: G02B

Claim:
1. A zoom lens consisting of, in order from the object side to the image side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a negative refractive power; and a fifth lens group having a positive refractive power; the distance between the first lens group and the second lens group constantly increasing, the distance between the second lens group and the third lens group constantly decreasing, the distance between the third lens group and the fourth lens group constantly changing, and the distance between the fourth lens group and the fifth lens group constantly increasing when changing magnification from the wide angle end to the telephoto end; the first lens group consisting of, in order from the object side to the image side, a 1-1 negative lens, a 1-2 positive lens, and a 1-3 positive lens; the fourth lens group consisting of, in order from the object side to the image side, a 4-1 negative lens, a 4-2 negative lens, and a 4-3 positive lens; and the fourth lens group moving toward the image side when changing focus from an object at a far distance to an object at a close distance.