JP2007286390A5

JP2007286390A5 -

Info

Publication number: JP2007286390A5
Application number: JP2006114127A
Authority: JP
Filing date: 2006-04-18
Publication date: 2009-04-30

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 negative refractive power;
A fifth lens group having a positive refractive power,
The air gap between the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group is changed to change from the wide-angle end to the telephoto end. A zoom lens for zooming,
At the telephoto end against the wide angle end,
The distance between the first lens group and the second lens group is enlarged,
An interval between the second lens group and the third lens group is reduced,
The second lens group is located on the image side at the telephoto end than at the wide-angle end,
The third lens group is positioned closer to the object side at the telephoto end than at the wide-angle end;
A zoom lens satisfying the following conditional expression:
3.00 <Lw / fw <9.90
0.50 <Lt / ft <2.25
Here, Lw and Lt are the total length of the zoom lens at the wide-angle end and the telephoto end, respectively, and fw and ft are the focal lengths of the entire zoom lens system at the wide-angle end and the telephoto end, respectively.

The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
−1.35 <f2 / fw <−0.40
−1.00 <f2 / ft <−0.10
Here, f2 is the focal length of the second lens group.

The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
0.80 <f3 / fw <2.40
0.10 <f3 / ft <1.00
Here, f3 is a focal length of the third lens group.

The first lens group is composed of one lens component when only two lenses having an air contact surface on the effective surface, that is, an object side surface and an image side surface are used as one lens component. The zoom lens according to claim 1.

The zoom lens according to claim 4, wherein the first lens group includes one positive single lens.

The zoom lens according to claim 5, wherein the positive single lens of the first lens group satisfies the following conditional expression.
70.0 <Vd11 <105.0
Vd11 is the Abbe number of the positive single lens in the first lens group.

The zoom lens according to claim 5, wherein the positive single lens of the first lens group satisfies the following conditional expression.
−1.50 <SF11 <−0.20
SF11 = (R11f + R11r) / (R11f−R11r) where R11f and R11r are the paraxial curvature radii of the object side surface and the image side surface of the positive single lens L11 of the first lens group, respectively.

5. The zoom lens according to claim 4, wherein the first lens group includes one cemented lens in which two lenses of a positive lens and a negative lens are cemented.

The zoom lens according to claim 8, wherein the following conditional expression is satisfied.
1.400 <Nd1p <1.620
65.0 <Vd1p <100.0
1.600 <Nd1n <2.100
18.0 <Vd1n <38.0
Here, Nd1p and Vd1p are the refractive index and Abbe number of the positive lens of the first lens group with respect to the d-line, and Nd1n and Vd1n are the refractive index and Abbe number of the negative lens of the first lens group with respect to the d-line, respectively.

A diaphragm for limiting an axial light beam on an image side of the second lens group and an object side of the fourth lens group, and the second lens group includes three or less lenses, and is the most object of the second lens group 4. The zoom lens according to claim 1, wherein a negative lens is disposed on the side, and a positive lens is disposed closest to the image side of the second lens group. 5.

The zoom lens according to claim 10, wherein the second lens group includes two single lenses of a negative single lens and a positive single lens in order from the object side.

The zoom lens according to claim 10, wherein the second lens group includes a negative single lens in order from the object side, and a cemented lens of a negative lens and a positive lens from the object side.

The zoom lens according to any one of claims 10 to 12, wherein a negative lens closest to the object side of the second lens group satisfies the following conditional expression.
0.10 <SF21 <1.60
SF21 = (R21f + R21r) / (R21f−R21r) where R21f and R21r are the paraxial radii of curvature of the object side surface and the image side surface of the negative lens closest to the object side in the second lens group.

The zoom lens according to claim 10, wherein the negative lens closest to the object side of the second lens group satisfies the following conditional expression.
1.750 <Nd21 <2.100
30.0 <Vd21 <50.0
Here, Nd21 and Vd21 are the refractive index and Abbe number for the d-line of the negative lens closest to the object side in the second lens group, respectively.

The zoom lens according to claim 10, wherein the positive lens closest to the image side of the second lens group satisfies the following conditional expression.
1.840 <Nd22 <2.100
15.0 <Vd22 <32.0
Here, Nd22 and Vd22 are the refractive index and Abbe number for the d-line of the positive lens closest to the image side in the second lens group, respectively.

16. The zoom lens according to claim 1, wherein the total number of lenses of the first lens group and the second lens group is four or less.

The third lens group includes a positive lens and a negative lens, the total number of lenses is three or less, and the total number of lens components is two or less, and the fourth lens group includes a positive lens and a negative lens. 17. The zoom lens according to claim 16, wherein the total number of lenses is two, and the fifth lens group is one positive lens.

A diaphragm for limiting the axial beam diameter is disposed between the second lens group and the third lens group, and the diaphragm moves integrally with the third lens group at the time of zooming. The zoom lens according to claim 1.

The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition.
4.0 <fw / ft <15.0
Here, fw is the focal length of the entire zoom lens system at the wide-angle end, and ft is the focal length of the entire zoom lens system at the telephoto end.

20. A zoom lens according to claim 1, and an electronic imaging device that is disposed on an image side of the zoom lens and that captures an image formed by the zoom lens and converts the image into an electrical signal. An imaging apparatus characterized by the above.

The imaging apparatus according to claim 20, wherein the imaging apparatus satisfies the following condition.
1.2 <fw / y ₁₀ <2.0
However, y ₁₀ is the effective image pickup plane of the electronic imaging device the distance to the farthest point from the center in (imageable plane) (maximum image height).

The imaging apparatus according to claim 20 or 21, further comprising a data processing portion that processes image data obtained by imaging with the electronic imaging element and outputs the processed image data as image data having a changed shape. An imaging apparatus characterized in that the lens satisfies the following condition when focusing on an object point at infinity.
0.75 <y ₀₇ / (fw · tan ω _07w ) <0.96
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is y ₁₀ , y ₀₇ = 0.7y ₁₀ , and ω _07w is a wide angle. It is an incident angle of view corresponding to a position y ₀₇ from the center on the imaging surface at the end.