Variable-power optical system, optical device, and method for manufacturing variable-power optical system

Abstract

Comprising a first lens group G 1 having positive refractive power, disposed at the most object side, and an image side lens group disposed at a side closer to an image than the first lens group G 1, upon zooming, at least a distance between the first lens group G 1 and the image side lens group being varied, the image side lens group comprising a vibration reduction lens group GVR which is moved so as to have a component in a direction perpendicular to the optical axis and a focusing lens group GF which is moved along the optical axis upon focusing, thereby providing a variable magnification optical system which has a higher optical performance, an optical apparatus and a method for manufacturing a variable magnification optical system.

1 - 14 . (canceled) 
     
     
         15 . A variable magnification optical system comprising, in order from an object side along an optical axis:
 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   an image side lens group,   upon zooming, distances between respective lens groups being varied,   the first lens group comprising, at a most object side, a cemented lens constructed by a negative lens cemented with a positive lens,   the image side lens group comprising a vibration reduction lens group which is movable with a movement component in a direction perpendicular to the optical axis, and   the following conditional expression being satisfied:
   0.10<| fvr|/f 4<0.80 
   where fvr denotes a focal length of the vibration reduction lens group and f4 denotes a focal length of the image side lens group.   
     
     
         16 . The variable magnification optical system according to  claim 15 , wherein
 upon zooming, the first lens group is fixed in position.   
     
     
         17 . The variable magnification optical system according to  claim 15 , wherein
 upon zooming, the image side lens group is fixed in position.   
     
     
         18 . The variable magnification optical system according to  claim 15 , wherein
 upon zooming, the second lens group is moved to the image side.   
     
     
         19 . The variable magnification optical system according to  claim 15 , wherein
 the image side lens group comprises a positive lens at a most object side.   
     
     
         20 . The variable magnification optical system according to  claim 15 , wherein
 the second lens group comprises, at a most object side, a cemented lens constructed by a positive lens cemented with a negative lens.   
     
     
         21 . The variable magnification optical system according to  claim 15 , wherein
 the image side lens group comprises a focusing lens group which is moved along the optical axis upon focusing.   
     
     
         22 . The variable magnification optical system according to  claim 21 , wherein
 the focusing lens group comprises, in order from the object side, a first focusing group and a second focusing group, and   the following conditional expression is satisfied:
   0.10<| fp|/f 4<0.45 
   where fp denotes a focal length of the second focusing group.   
     
     
         23 . The variable magnification optical system according to  claim 22 , wherein
 the following conditional expression is satisfied:
   0.20<(− fn )/ f 4<0.60
 
   where fn denotes a focal length of the first focusing group.   
     
     
         24 . An optical apparatus equipped with the variable magnification optical system according to  claim 15 . 
     
     
         25 . A method for manufacturing 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 an image side lens group, the method comprising:
 arranging the lens groups such that, upon zooming, distances between respective lens groups are varied,   constructing the first lens group to comprise, at a most object side, a cemented lens constructed by a negative lens cemented with a positive lens,   constructing the image side lens group to comprise a vibration reduction lens group which is movable with a movement component in a direction perpendicular to the optical axis, and   satisfying the following conditional expression:
   0.10<| fvr|/f 4<0.80 
   where fvr denotes a focal length of the vibration reduction lens group and f4 denotes a focal length of the image side lens group.