JP2008139837A5

JP2008139837A5 -

Info

Publication number: JP2008139837A5
Application number: JP2007260087A
Authority: JP
Filing date: 2007-10-03
Publication date: 2010-11-11
Anticipated expiration: 2027-10-03

Claims

In order from the object side, the first lens unit has a negative refractive power and a second lens unit has a positive refractive power.
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is reduced,
The first lens group includes, in order from the object side, a first lens having a negative refractive power and a second lens having a positive refractive power,
The second lens group includes, in order from the object side, a third lens having a positive refractive power, a fourth lens having a negative refractive power with a convex surface facing the object side, and a fifth lens having a positive refractive power. These three lenses are arranged without being joined to each other,
A zoom lens satisfying the following conditions:
-1.48 <(r2 + r1) / (r2-r1) <-1.00
However,
r1: radius of curvature of the object side surface of the fourth lens r2: radius of curvature of the image side surface of the fourth lens

The zoom lens according to claim 1, wherein the following condition is satisfied.
−1.48 <(r2 + r1) / (r2−r1) ≦ −1.359
However,
r1: radius of curvature of the object side surface of the fourth lens
r2: radius of curvature of the image side surface of the fourth lens

The zoom lens according to claim 1 or 2, characterized in that the following condition is satisfied.
0.20 <S1 / ft <0.32
However,
S1: Lens thickness ft of the first lens group: Focal length of the zoom lens in the telephoto end state

The zoom lens according to any one of claims 1 to 3, wherein the following condition is satisfied.
1.00 <Fw × fw / (− f1) <1.90
However,
Fw: F number of the zoom lens in the wide-angle end state fw: Focal length f1 of the zoom lens in the wide-angle end state f1: Focal length of the first lens group

The zoom lens according to claim 1, any one of 4, characterized in that the following condition is satisfied.
0.20 <S2 / ft <0.35
However,
S2: Lens thickness of the second lens group ft: Focal length of the zoom lens in the telephoto end state

The zoom lens according to any one of claims 1 5, characterized in that the following condition is satisfied.
20 <ν3-ν4 <37
However,
ν3: Abbe number with respect to d-line (wavelength λ = 587.6 nm) of the third lens ν4: Abbe number with respect to d-line (wavelength λ = 587.6 nm) of the fourth lens

The third lens is a zoom lens according to any one of claims 1 6, characterized in that it has an aspherical surface.

The image side surface of the third lens is a zoom lens according to any one of claims 1 7, characterized in that an aspherical surface.

The image side surface of the first lens, the zoom lens according to any one of claims 1 8, characterized in that an aspherical surface.

The zoom lens according to any one of claims 1 to 9 , wherein the fifth lens is a meniscus lens having a concave surface directed toward the object side.

The refractive index of the fourth lens is a zoom lens according to claim 1, any one of 10, wherein the greater than 1.80.

An optical apparatus characterized by having a zoom lens according to any one of claims 1 to 11.

In order from the object side, the first lens unit has a negative refractive power and a second lens unit has a positive refractive power.
The first lens group includes, in order from the object side, a first lens having a negative refractive power and a second lens having a positive refractive power,
The second lens group includes, in order from the object side, a third lens having a positive refractive power, a fourth lens having a negative refractive power with a convex surface facing the object side, and a fifth lens having a positive refractive power. These three lenses are arranged without being joined to each other, and a zoom lens zooming method that satisfies the following conditions:
A zoom lens zooming method, wherein zooming is performed from the wide-angle end state to the telephoto end state by narrowing the distance between the first lens group and the second lens group.
-1.48 <(r2 + r1) / (r2-r1) <-1.00
However,
r1: radius of curvature of the object side surface of the fourth lens r2: radius of curvature of the image side surface of the fourth lens

The zoom lens according to claim 13, wherein the following condition is satisfied.
−1.48 <(r2 + r1) / (r2−r1) ≦ −1.359
However,
r1: radius of curvature of the object side surface of the fourth lens
r2: radius of curvature of the image side surface of the fourth lens

The zoom lens zooming method according to claim 13 or 14 , wherein the following condition is satisfied.
0.20 <S1 / ft <0.32
However,
S1: Lens thickness ft of the first lens group: Focal length of the zoom lens in the telephoto end state

The zoom lens zooming method according to any one of claims 13 to 15, wherein the following condition is satisfied.
1.00 <Fw × fw / (− f1) <1.90
However,
Fw: F number of the zoom lens in the wide-angle end state fw: Focal length f1 of the zoom lens in the wide-angle end state f1: Focal length of the first lens group

The zoom lens zooming method according to any one of claims 13 to 16 , wherein the following condition is satisfied.
0.20 <S2 / ft <0.35
However,
S2: Lens thickness of the second lens group ft: Focal length of the zoom lens in the telephoto end state

The zoom lens zooming method according to any one of claims 13 to 17 , wherein the following condition is satisfied.
20 <ν3-ν4 <37
However,
ν3: Abbe number with respect to d-line (wavelength λ = 587.6 nm) of the third lens ν4: Abbe number with respect to d-line (wavelength λ = 587.6 nm) of the fourth lens

The zoom lens zooming method according to any one of claims 13 to 18 , wherein the third lens has an aspherical surface.

The zoom lens zooming method according to any one of claims 13 to 19 , wherein the image side surface of the third lens is an aspherical surface.

The image side surface of the first lens, a method for zooming the zoom lens according to claims 13 to any one of 20, wherein the non is spherical.

The zoom lens zooming method according to any one of claims 13 to 21 , wherein the fifth lens is a meniscus lens having a concave surface directed toward the object side.

The zoom lens zooming method according to any one of claims 13 to 22 , wherein the refractive index of the fourth lens is greater than 1.80.