Patent ID: 9235034
Filing Date: 2016-01-12
CPC Classification: G02B

Claim Text:
1. A variable magnification optical system consisting of: a first lens group having positive refractive power, and which is fixed during magnification change; a second lens group having negative refractive power; a third lens group having negative refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power, and which is fixed during magnification change, which are in this order from an object side, wherein the second lens group, the third lens group and the fourth lens group move in such a manner that a distance between the first lens group and the second lens group constantly becomes longer and a distance between the second lens group and the third lens group constantly becomes longer, compared with a wide-angle end, and a distance between the third lens group and the fourth lens group changes and a distance between the fourth lens group and the fifth lens group changes when magnification is changed from the wide-angle end to a telephoto end.