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

A method for manufacturing a zoom optical system consisting of, in order from an object on an optical axis:

• a first lens group having a positive refractive power;
• and a rear group that includes a plurality of lens groups,
• the method comprising disposing the first lens group and the rear group in a lens barrel in order from the object on the optical axis so that:
• upon zooming from a wide angle end to a telephoto end, a distance between the first lens group and the rear group changes, and distances between lens groups constituting the rear group change,
• the rear group includes, in order from the object:
• a first focusing lens group having a negative refractive power;
• and a second focusing lens group having a negative refractive power, and
• both the first focusing lens group and the second focusing lens group move on the optical axis toward an image upon focusing from infinity to a short distance position,
• the method further comprising one of the following features A and B:
• the feature A comprising:
• satisfying the following conditional expression:
• 0.30<fF1/fF2≤0.672
• where
• fF1:
• a focal length of the first focusing lens group, and
• fF2:
• a focal length of the second focusing lens group, and
• the feature B comprising:
• the rear group comprises at least four lens groups which are disposed closer to the object than the first focusing lens group, and
• satisfying the following conditional expression:
• 0.30<fF1/fF2<1.50
• where
• fF1:
• a focal length of the first focusing lens group, and
• fF2:
• a focal length of the second focusing lens group.

A zoom optical system consisting of, in order from an object on an optical axis:

• a first lens group having a positive refractive power;
• and a rear group that includes a plurality of lens groups, wherein
• upon zooming from a wide angle end to a telephoto end, a distance between the first lens group and the rear group changes, and distances between lens groups constituting the rear group change,
• the rear group includes a first focusing lens group having a negative refractive power, and a second focusing lens group having a negative refractive power, which is disposed closer to an image than the first focusing lens group,
• the rear group comprises at least four lens groups which are disposed closer to the object than the first focusing lens group,
• both the first focusing lens group and the second focusing lens group move on the optical axis toward an image upon focusing from infinity to a short distance position, and
• the following conditional expression is satisfied:
• 0.30<fF1/fF2<1.50
• where
• fF1:
• a focal length of the first focusing lens group, and
• fF2:
• a focal length of the second focusing lens group.