Zoom optical system, optical apparatus and method for manufacturing the zoom optical system

1. A zoom optical system comprising, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; and a subsequent group including at least one lens group, wherein

upon zooming, distances between the first lens group and the second lens group and between the second lens group and the subsequent group change,

the subsequent group comprises a focusing group having negative refractive power for focusing,

the focusing group comprises at least one lens having positive refractive power and at least one lens having negative refractive power,

the first lens group comprises a 1-1st lens having positive refractive power and is disposed closest to the object, and

the following conditional expressions are satisfied:

0.85< n 1 P/n 1 N< 1.00

0.56<ν FP/νFN< 0.82

where,

n1P denotes a refractive index of a lens with largest positive refractive power in the first lens group,

n1N denotes a refractive index of a lens with largest negative refractive power in the first lens group,

νFP denotes an Abbe number of the lens with the largest positive refractive power in the focusing, group, and

νFN denotes an Abbe number of the lens with the largest negative refractive power in the focusing group.

2. The zoom optical system according to claim 1 , wherein

a following conditional expression is satisfied:

4.30< f 1/(− f 2)<5.00

where,

f1 denotes a focal length of the first lens group, and

f2 denotes a focal length of the second lens group.

3. The zoom optical system according to claim 1 , wherein the first lens group moves toward the object upon zooming from a wide angle end state to a telephoto end state.

4. The zoom optical system according to claim 1 , wherein

a following conditional expression is satisfied:

1.00< nFP/nFN< 1.20

where,

nFP denotes a refractive index of a lens with largest positive refractive power in the focusing group, and

nFN denotes a refractive index of a lens with largest negative refractive power in the focusing group.

5. The zoom optical system according to claim 1 , wherein the first lens group comprises, in order from the object: the 1-1st lens; a 1-2nd lens having negative refractive power; and a 1-3rd lens having positive refractive power.

6. The zoom optical system according to claim 1 , wherein the second lens group comprises, in order from the object: a 2-1st lens having negative refractive power; a 2-2nd lens having positive refractive power; and a 2-3rd lens having negative refractive power.

7. An optical apparatus comprising the zoom optical system according to claim 1 .

8. A zoom optical system comprising, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; and a subsequent group including at least one lens group, wherein

upon zooming, all of the first lens group, the second lens group and the subsequent group are moved along an optical axis, and distances between the first lens group and the second lens group and between the second lens group and the subsequent group change,

the subsequent group comprises a focusing group having negative refractive power for focusing,

the first lens group comprises a 1-1st lens having positive refractive power and is disposed closest to the object, and

the following conditional expression is satisfied:

0.85< n 1 P/n 1 N< 1.00

where,

n1P denotes a refractive index of a lens with largest positive refractive power in the first lens group, and

n1N denotes a refractive index of a lens with largest negative refractive power in the first lens group.

9. A method for manufacturing a zoom optical system which comprises, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; and a subsequent group including at least one lens group,

the method comprising arranging the lens groups in a lens barrel so that:

upon zooming, distances between the first lens group and the second lens group and between the second lens group and the subsequent group change,

the subsequent group comprises a focusing group having negative refractive power for focusing, and

the first lens group comprises a 1-1st lens having positive refractive power and is disposed closest to the object,

the method further comprising at least one of the following features (A) or (B):

(A) configuring the focusing group to comprise at least one lens having positive refractive power and at least one lens having negative refractive power, and

satisfying the following conditional expressions:

0.85< n 1 P/n 1 N< 1.00

0.56<ν FP/νFN< 0.82

where,

n1P denotes a refractive index of a lens with largest positive refractive power in the first lens group,

n1N denotes a refractive index of a lens with largest negative refractive power in the first lens group,

νFP denotes an Abbe number of the lens with the largest positive refractive power in the focusing group, and

νFN denotes an Abbe number of the lens with the largest negative refractive power in the focusing group;

(B) arranging the lens groups such that upon zooming, all of the first lens group, the second lens group and the subsequent group are moved along an optical axis, and

satisfying the following conditional expression:

0.85< n 1 P/n 1 N< 1.00

where,

n1P denotes a refractive index of a lens with largest positive refractive power in the first lens group, and

n1N denotes a refractive index of a lens with largest negative refractive power in the first lens group.