JP2007323054A5

JP2007323054A5 -

Info

Publication number: JP2007323054A5
Application number: JP2007112167A
Authority: JP
Filing date: 2007-04-20
Publication date: 2010-08-05
Anticipated expiration: 2027-04-20

Claims

A first lens group having an optical path bending optical element and having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power in order from the object side along the optical axis. And a fourth lens group having a positive refractive power,
When the focal length changes from the wide-angle end state to the telephoto end state, the first lens group is fixed with respect to the image plane, the distance between the first lens group and the second lens group increases, An interval between the second lens group and the third lens group is reduced, and an interval between the third lens group and the fourth lens group is reduced;
The first lens group includes a negative lens;
A zoom lens satisfying the following conditions:
nd1> 1.900
νd1 <20.50
However,
nd1: refractive index of d-line of the negative lens νd1: Abbe number of d-line of the negative lens

2. The zoom lens according to claim 1, wherein the third lens group is fixed with respect to the image plane when the focal length changes from the wide-angle end state to the telephoto end state.

The zoom lens according to claim 1, wherein the third lens group includes at least one cemented lens.

The zoom lens according to claim 1, wherein the negative lens satisfies the following conditional expression.
nd1> 1.94
However,
nd1: refractive index of d-line of the negative lens

The third lens group includes, in order from the object side along the optical axis, a positive lens having a convex surface facing the object side, a positive lens having a convex surface facing the object side, and a negative lens having a concave surface facing the image side. 5. The zoom lens according to claim 1, wherein the zoom lens includes a cemented lens having a refractive power of 1 to 4.

The fourth lens group includes, in order from the object side along the optical axis, a positive lens having a convex surface facing the object side, a positive lens having a convex surface facing the object side, and a negative lens having a concave surface facing the image side. The zoom lens according to any one of claims 1 to 5, wherein the zoom lens includes a cemented lens having a refractive power of 1 to 5.

The zoom lens according to claim 1, wherein the following condition is satisfied.
0.5 <f4 / f3 <1.1
However,
f3: focal length of the third lens group f4: focal length of the fourth lens group

The zoom lens according to claim 1, wherein the following condition is satisfied.
0.5 <f4 / f3 <1.0
However,
f3: focal length of the third lens group
f4: focal length of the fourth lens group

The zoom lens according to claim 1, wherein the following condition is satisfied.
0.5 <f4 / f3 <0.95
However,
f3: focal length of the third lens group
f4: focal length of the fourth lens group

The negative lens of the first lens group is a negative meniscus lens having a convex surface facing the object side,
The first lens group includes, in order from the object side along the optical axis, the negative meniscus lens, the optical path bending optical element, and a positive lens having a convex surface facing the object side. The zoom lens according to any one of 1 to 9 .

The optical path bending optical element is a right angle prism;
The zoom lens according to any one of claims 1 to 10, characterized in that the following condition is satisfied.
ndp> 1.800
However,
ndp: refractive index of d-line of the right-angle prism

The zoom lens according to any one of claims 1 to 11 , wherein the first lens group includes at least one aspherical lens.

The second lens group includes, in order from the object side along the optical axis, a negative lens having a concave surface facing the image side, a negative lens having a negative refractive power and a negative lens having a concave surface facing the object side. the zoom lens according to claim 1, any one of 12, characterized in that they are composed of.

Wherein at least the zoom lens according to any one of claims 1 to 13, characterized in that it comprises one aspherical lens in the second lens group.

The zoom lens according to any one of claims 1 to 14, characterized in that the following condition is satisfied.
0.8 <(− f2) / fw <1.3
However,
fw: focal length of the entire zoom lens system in the wide-angle end state f2: focal length of the second lens group

The zoom according to any one of claims 1 to 15 , wherein the second lens group is moved toward the object side along the optical axis to perform focus adjustment from an object at infinity to a short-distance object. lens.

The zoom lens according to any one of claims 1 to 16 , wherein the following condition is satisfied.
1.5 <f1 / (− f2) <4.0
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

Wherein at least the zoom lens according to any one of claims 1 to 17, characterized in that it comprises one aspherical lens in the third lens group.

The zoom lens according to any one of claims 1 to 18 , wherein the fourth lens group includes at least one aspherical lens.

An optical apparatus comprising the zoom lens according to any one of claims 1 to 19 .

A first lens group having an optical path bending optical element and having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power in order from the object side along the optical axis. And a fourth lens group having a positive refractive power,
The first lens group includes a negative lens, and the negative lens satisfies the following conditions:
When the focal length changes from the wide-angle end state to the telephoto end state, the first lens group is fixed with respect to the image plane, the distance between the first lens group and the second lens group increases, The second lens group and the fourth lens group are light so that the distance between the second lens group and the third lens group decreases and the distance between the third lens group and the fourth lens group decreases. A zoom lens zooming method characterized by moving along an axis.
nd1> 1.900
νd1 <20.50
However,
nd1: refractive index of d-line of the negative lens νd1: Abbe number of d-line of the negative lens

A first lens group having an optical path bending optical element and having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power in order from the object side along the optical axis. And a fourth lens group having a positive refractive power,
When the focal length changes from the wide-angle end state to the telephoto end state, the first lens group is fixed with respect to the image plane, the distance between the first lens group and the second lens group increases, An interval between the second lens group and the third lens group is reduced, and an interval between the third lens group and the fourth lens group is reduced;
The first lens group includes a negative lens, and the negative lens satisfies the following conditions:
A focus adjustment method for a zoom lens, wherein the second lens group is moved to the object side along the optical axis to perform focus adjustment from an object at infinity to a short-distance object.
nd1> 1.900
νd1 <20.50
However,
nd1: refractive index of d-line of the negative lens νd1: Abbe number of d-line of the negative lens