JP2009156893A5

JP2009156893A5 -

Info

Publication number: JP2009156893A5
Application number: JP2007331499A
Authority: JP
Filing date: 2007-12-25
Publication date: 2011-01-27
Anticipated expiration: 2027-12-25

Claims

From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
A fourth lens group having a positive refractive power,
The fourth lens group, in order from the object side,
A 4a partial lens group having positive refractive power;
A 4b partial lens group having negative refractive power,
The 4a partial lens group includes a negative meniscus lens having a convex surface facing the object side,
A variable magnification optical system that performs camera shake correction by moving the fourth lens group in the direction orthogonal to the optical axis.

2. The variable magnification optical system according to claim 1 , wherein the fourth lens group further includes a fourth c partial lens group having a positive refractive power on the image plane side from the fourth b partial lens group.

When the focal length of the first lens group is f1 and the focal length of the third lens group is f3, the following expression 0.8 <f1 / f3 <1.3
The zoom optical system according to claim 1 , wherein the zoom lens system satisfies the following condition.

When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, the following formula 0.5 <f3 / f4 <1.2
The variable magnification optical system as described in any one of Claims 1-3 which satisfy | fills these conditions.

The variable power optical system according to any one of claims 1 to 4 , wherein the fourth b partial lens group includes one cemented lens.

The variable magnification optical system according to any one of claims 1 to 5, wherein an aperture stop is disposed between the third lens group and the fourth lens group.

The variable power optical system according to claim 1, wherein the third lens group performs focusing from a long-distance object to a short-distance object.

When the lens position state changes from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group increases. The variable power optical system according to any one of claims 1 to 7, which decreases.

The zoom optical system according to any one of claims 1 to 8 , wherein the first lens group is fixed when a lens position state changes from a wide-angle end state to a telephoto end state.

The zoom optical system according to any one of claims 1 to 9 , wherein the fourth lens group is fixed when the lens position state changes from the wide-angle end state to the telephoto end state.

Optical apparatus including the variable magnification optical system according to any one of claims 1 to 10.

From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
A fourth lens group having a positive refractive power,
The fourth lens group, in order from the object side,
A 4a partial lens group having positive refractive power;
A 4b partial lens group having negative refractive power,
The 4a partial lens group includes a negative meniscus lens having a convex surface facing the object side,
A zooming method for a zooming optical system that corrects camera shake by moving the fourth lens group in the direction orthogonal to the optical axis,
When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes. A zooming method for a zooming optical system configured to change.