JP2007256604A5

JP2007256604A5 -

Info

Publication number: JP2007256604A5
Application number: JP2006080485A
Authority: JP
Filing date: 2006-03-23
Publication date: 2009-04-23
Anticipated expiration: 2026-03-23

Claims

From the 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;
A fourth lens group having a positive refractive power,
The first lens group, the second lens group, the third lens group, and the fourth lens group move in the optical axis direction so as to change the air gap between the respective lens groups. A zoom lens that zooms from the wide-angle end to the telephoto end,
The distance between the first lens group and the second lens group at the telephoto end with respect to the wide-angle end increases.
The distance between the second lens group and the third lens group decreases,
The third lens group includes four lenses in order from the object side: a first lens that is a positive lens, a second lens that is a negative lens, a third lens that is a positive lens, and a fourth lens that is a negative lens.
The zoom lens, wherein the second lens in the third lens group is joined to at least one of the first lens and the third lens on an optical axis.

From the 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;
A fourth lens group having a positive refractive power,
The first lens group, the second lens group, the third lens group, and the fourth lens group move in the optical axis direction so as to change the air gap between the respective lens groups. A zoom lens that zooms from the wide-angle end to the telephoto end,
The distance between the first lens group and the second lens group at the telephoto end with respect to the wide-angle end increases.
The distance between the second lens group and the third lens group decreases,
The third lens group includes four lenses in order from the object side: a first lens that is a positive lens, a second lens that is a negative lens, a third lens that is a positive lens, and a fourth lens that is a negative lens.
A zoom lens, wherein at least one of the second lens and the fourth lens in the third lens group is a biconcave lens.

2. The zoom lens according to claim 1, wherein at least one of the second lens and the fourth lens in the third lens group is a biconcave lens.

The zoom lens according to any one of claims 1 to 3,
The first lens group is located on the object side at the telephoto end with respect to the wide-angle end,
A zoom lens, wherein the third lens group is located on the object side.

5. The zoom lens according to claim 1, wherein each of the first lens group, the second lens group, and the fourth lens group is composed of one or two lenses.

2. The zoom lens according to claim 1, wherein an air gap is sandwiched between the third lens and the fourth lens of the third lens group.

7. The zoom lens according to claim 1, wherein an object side surface and an image side surface of the second lens of the third lens group are cemented surfaces with adjacent positive lenses. 8. .

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
0.3 <Ih / fg3 <1.2
Here, Ih is the maximum image height, and fg3 is the focal length of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
2 <fg1 / fg3 <7
Here, fg1 is the focal length of the first lens group, and fg3 is the focal length of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
−1.5 <fg2 / fg3 <−0.5
Here, fg2 is the focal length of the second lens group, and fg3 is the focal length of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
0.1 <fg3 / fg4 <0.85
Here, fg3 is the focal length of the third lens group, and fg4 is the focal length of the fourth lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
1.2 <β2T / β2W <5
Where β2T is the lateral magnification at the telephoto end of the second lens group, and β2W is the lateral magnification at the wide-angle end of the second lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
1.5 <β3T / β3W <5
However, β3T is a lateral magnification at the telephoto end of the third lens group, and β3W is a lateral magnification at the wide-angle end of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
0.1 <Dg1 / D <2.0
However, Dg1 is a moving distance from the wide-angle end to the telephoto end of the first lens group, and D is a total value of axial distances from the entrance surface to the exit surface for each lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
0.1 <Dg3 / D <2.0
However, Dg3 is a moving distance from the wide-angle end to the telephoto end of the third lens group, and D is a total value of axial distances from the entrance surface to the exit surface for each lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
-1.5 <fg3L123 / fg3L4 <-0.7
Here, fg3L123 is the combined focal length of the first, second and third lenses of the third lens group, and fg3L4 is the focal length of the fourth lens of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
−1.25 <(rg3L1f + rg3L1r) / (rg3L1f−rg3L1r) <− 0.15
Here, rg3L1f is the radius of curvature of the object side surface of the first lens of the third lens group, and rg3L1r is the radius of curvature of the image side surface of the first lens of the third lens group.

6. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
−0.8 <(rg3L4f + rg3L4r) / (rg3L4f−rg3L4r) <1.5
Here, rg3L4f is the radius of curvature of the object side surface of the fourth lens of the third lens group, and rg3L4r is the radius of curvature of the image side surface of the fourth lens of the third lens group.

6. The zoom lens according to claim 1, wherein the second lens group includes only two lenses, a negative lens and a positive lens, from the object side.

The zoom lens according to any one of claims 1 to 5, further comprising an aperture stop disposed between the second lens group and the third lens group.

The third lens group is located on the object side at the telephoto end with respect to the wide angle end, and the brightness stop is located on the object side at the telephoto end with respect to the wide angle end. The described zoom lens.

The zoom lens according to any one of claims 1 to 21, wherein the zoom lens satisfies the following conditional expression.
3.5 <fT / fW
Here, fT is the focal length of the entire zoom lens system at the telephoto end, and fW is the focal length of the entire zoom lens system at the wide angle end.

At least one zoom lens according to claim 1;
An image pickup apparatus, comprising: an image pickup device disposed on an image side of the zoom lens and converting an image formed by the zoom lens into an electric signal.