Variable magnification optical system, optical device, and method for producing variable magnification optical system

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;
• and a fourth lens group having negative refractive power;
• upon zooming, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, and a distance between the third lens group and the fourth lens group being varied, and the second lens group and the third lens group being moved;
• upon focusing from an infinitely distant object to a closely distant object, the third lens group being moved along an optical axis;
• and
• the following conditional expression being satisfied:
• 0.60<f1/f3<2.60
• where f1 denotes a focal length of the first lens group, and f3 denotes a focal length of the third lens group.

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;
• and a rear lens group;
• upon zooming, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, and a distance between the third lens group and the rear lens group being varied, and the second lens group and the third lens group being moved;
• at least a portion of the rear lens group being moved as a vibration reduction lens group to have a movement component in a direction perpendicular to an optical axis;
• and
• the following conditional expression being satisfied:
• 5.00<f1/(−f2)<10.00
• where f1 denotes a focal length of the first lens group, and f2 denotes a focal length of the second lens group.

A method for manufacturing a variable magnification optical system comprising at least one of the following features (A) and (B):

• (A) arranging, 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;
• and a fourth lens group having positive refractive power;
• constructing such that, upon zooming, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, and a distance between the third lens group and the fourth lens group are varied, and the second lens group and the third lens group are moved;
• constructing such that, upon focusing from an infinitely distant object to a closely distant object, the third lens group is moved along an optical axis;
• and
• satisfying the following conditional expression:
• 0.60<f1/f3<2.60
• where f1 denotes a focal length of the first lens group, and f3 denotes a focal length of the third lens group;
• (B) arranging, 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;
• and a rear lens group;
• constructing such that, upon zooming, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, and a distance between the third lens group and the rear lens group are varied, and the second lens group and the third lens group are moved;
• constructing at least a portion of the rear lens group is moved as a vibration reduction lens group to have a movement component in a direction perpendicular to the optical axis;
• and
• satisfying the following conditional expression:
• 5.00<f1/(−f2)<10.00
• where f1 denotes a focal length of the first lens group, and f2 denotes a focal length of the second lens group.