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

Abstract

Comprising, in order from an object side: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; and a fourth lens group G4 having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, the first lens group G1 being fixed in the position in the direction of the optical axis, at least the second lens group G2 and the third lens group G3 being moved in the direction of the optical axis such that a distance between the first lens group G1 and the second lens group G2 is increased and a distance between the second lens group G2 and the third lens group G3 is decreased; and a predetermined conditional expression being satisfied, thereby providing a variable magnification optical system which can suppress variations in aberrations upon zooming and having excellent optical performance from a wide angle end state to a telephoto end state, an optical apparatus, and a method for manufacturing a variable magnification optical system.

1 . 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 positive refractive power;
 upon zooming from a wide-angle end state to a telephoto end state, the first lens group being fixed in a position in the direction of the optical axis, and at least the second lens group and the third lens group being moved in the direction of the optical axis such that a distance between the first lens group and the second lens group is increased and a distance between the second lens group and the third lens group is decreased;   at least a portion of the first lens group to the fourth lens group being moved to have a component in a direction perpendicular to the optical axis; and   the following conditional expression being satisfied:
   −1.20< fw   2 /( f 13 w×f 4)<−0.20
 
   where f13w denotes a composite focal length of the first lens group to the third lens group in the wide angle end state, f4 denotes a focal length of the fourth lens group, and fw denotes a focal length of the variable magnification optical system in the wide angle end state.   
     
     
         2 - 46 . (canceled)