JP2023058744A5

JP2023058744A5 -

Info

Publication number: JP2023058744A5
Application number: JP2023027904A
Authority: JP
Filing date: 2023-02-27
Publication date: 2023-09-01
Anticipated expiration: 2036-11-21

Description

第１の態様に係る変倍光学系は、物体側から順に並んだ、正の屈折力を有する第１レンズ群と、負の屈折力を有する第２レンズ群と、正の屈折力を有する第３レンズ群と、後続レンズ群とを有し、変倍の際、前記第１レンズ群と前記第２レンズ群との間隔が変化し、前記第２レンズ群と前記第３レンズ群との間隔が変化し、前記第３レンズ群と前記後続レンズ群との間隔が変化し、前記後続レンズ群は、合焦の際に移動する合焦レンズ群を有し、前記第１レンズ群は、前記第１レンズ群の最も物体側に配置された正の単レンズを有し、前記第３レンズ群は、前記第３レンズ群の最も物体側に配置された正の単レンズと、前記第３レンズ群内に絞りを有し、前記第２レンズ群が以下の条件式を満足する部分群を有し、
１．４０＜ｆｖｒ／ｆ２＜２．３０
１．８０＜ｆ１／ｆｗ＜３．５０
さらに以下の条件式を満足する。
３．２０＜ｆ１／ｆ３＜５．００
但し、ｆｖｒ：前記部分群の焦点距離、
ｆ２：前記第２レンズ群の焦点距離、
ｆ１：前記第１レンズ群の焦点距離、
ｆｗ：広角端状態における前記変倍光学系の焦点距離、
ｆ３：前記第３レンズ群の焦点距離。
A variable power optical system according to a first aspect comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a second lens group having positive refractive power, which are arranged in order from the object side. It has three lens groups and a subsequent lens group, and when zooming, 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, the spacing between the third lens group and the trailing lens group varies, the trailing lens group having a focusing lens group that moves during focusing, and the first lens group having the a positive single lens arranged closest to the object side of the first lens group, and the third lens group comprises a positive single lens arranged closest to the object side of the third lens group, and the third lens having an aperture in the group, the second lens group having a subgroup that satisfies the following conditional expression,
1.40<fvr/f2<2.30
1.80<f1/fw<3.50
Furthermore, the following conditional expression is satisfied.
3.20<f1/f3<5.00
where fvr is the focal length of the subgroup;
f2: focal length of the second lens group;
f1: focal length of the first lens group;
fw: the focal length of the variable magnification optical system in the wide-angle end state;
f3: focal length of the third lens group.

Claims

It has a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a subsequent lens group arranged in order from the object side. ,
During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, and the third lens group and the subsequent lens change. The distance between the groups changes,
the trailing lens group has a focusing lens group that moves during focusing;
The first lens group has a positive single lens disposed closest to the object side of the first lens group,
the third lens group has a positive single lens disposed closest to the object side of the third lens group and an aperture in the third lens group;
The second lens group has a subgroup that satisfies the following conditional expression,
1.40<fvr/f2<2.30
1.80<f1/fw<3.50
A variable power optical system that further satisfies the following conditional expression.
3.20<f1/f3<5.00
where fvr is the focal length of the subgroup;
f2: focal length of the second lens group;
f1: focal length of the first lens group;
fw: the focal length of the variable magnification optical system in the wide-angle end state;
f3: focal length of the third lens group.

2. A variable magnification optical system according to claim 1, which satisfies the following conditional expression.
0.84<(-f2)/f3<1.20

3. A variable-magnification optical system according to claim 1, which satisfies the following conditional expression.
0.18<(-fF)/f1<0.30
where fF is the focal length of the focusing lens group

4. The variable magnification optical system according to claim 1, wherein the focusing lens group has at least one lens with positive refractive power and at least one lens with negative refractive power.

5. The variable power optical system according to claim 1, wherein the subgroup comprises a lens having negative refractive power and a lens having positive refractive power, arranged in order from the object side.

6. A variable magnification optical system according to claim 5, which satisfies the following conditional expression.
0.80<nN/nP<1.00
However, nN: the refractive index of the lens having negative refractive power in the subgroup
nP: refractive index of the lens with positive refractive power in the subgroup

7. A variable magnification optical system according to claim 5 or 6, which satisfies the following conditional expression.
1.20<νN/νP<2.40
where νN: Abbe number of the lens having negative refractive power in the subgroup
νP: Abbe number of the lens with positive refractive power in the subgroup

The subsequent lens group includes a lens having negative refractive power arranged on the image side of the focusing lens group and a lens having positive refractive power arranged on the image side of the lens having negative refractive power. The variable power optical system according to any one of claims 1 to 6, having

9. A variable power optical system according to claim 8, which satisfies the following conditional expression.
0.70<(-fN)/fP<2.00
where fN is the focal length of the lens having negative refractive power disposed on the image side of the focusing lens group
fP: focal length of the lens with positive refractive power arranged on the image side of the lens with negative refractive power

An optical instrument comprising the variable magnification optical system according to any one of claims 1 to 9.