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

A method for manufacturing a zoom optical system which comprises, in order from an object:

• a first lens group having positive refractive power;
• an intermediate group including at least one lens group and having negative refractive power as a whole;
• an intermediate side lens group having positive refractive power;
• a subsequent side lens group having positive refractive power;
• and a subsequent group including at least one lens group,
• the method comprising a step of arranging the lens groups in a lens barrel so that:
• upon zooming, distances between the first lens group and the intermediate group, between the intermediate group and the intermediate side lens group, between the intermediate side lens group and the subsequent side lens group, and between the subsequent side lens group and the subsequent group change;
• the subsequent side lens group moves upon focusing;
• and
• the intermediate group comprises a partial group satisfying following conditional expressions:
• 1.4<fvr/fMt<2.5;
• and
• 0.15<(−fvr)/ft<0.35
• where,
• fvr denotes a focal length of the partial group,
• fMt denotes a focal length of the intermediate group in a telephoto end state, and
• ft denotes a focal length of the zoom optical system in the telephoto end state,
• wherein the partial group is a vibration-proof lens group movable to comprise a component in a direction orthogonal to an optical axis to correct image blur, and
• wherein the lens group disposed closest to an image has negative refractive power.