Patent ID: 11899189
Assignee: NIKON CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G  H

Claim 15:
16. A variable magnification optical system comprising, in order from an object side: 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;
upon varying a magnification, distances between the neighboring respective lens groups being varied; and
the following conditional expressions being satisfied:

0.64<f4/(−f2)<2.20

1.00<f3/(−f2)<3.00

where f4 denotes a focal length of the fourth lens group, f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group.