JP2001356266A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens consisting of a small number of lenses such as four or five lenses and having a high variable power ratio such as the one exceeding 3. SOLUTION: In the case of constituting the zoom lens of two groups, it is constituted of a 1st group having positive refractive power, an aperture diaphragm and a 2nd group having negative refractive power, and the 1st group having the positive refractive power is constituted of a negative lens and a positive lens, and the 2nd group having the negative refractive power is constituted of a positive lens and a negative lens, and then it satisfies a condition (1). (1) 3<ft/fw<5 In the case of constituting the zoom lens of three groups, it is constituted of a 1st group having positive refractive power, a 2nd group having negative refractive power and a 3rd group having negative refractive power and satisfies a condition (2). (2) 2.5<ft/fw<5.5 Provided that ft means the focal distance on a telephoto end side and fw means the focal distance on a wide-angle end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small zoom lens having a small number of lenses, for example, a zoom lens suitable for a photographing lens of a silver halide camera.

[0002]

2. Description of the Related Art In recent years, as the size and cost of cameras have been reduced, the demand for zoom lenses having a high zoom ratio has also increased. In particular, the number of lenses is 4
There is a demand for a lens system which is compact with as few as five to five lenses and has a large zoom ratio. 5 lenses
Japanese Patent Application Laid-Open No. 4-2644 as an example of a zoom lens composed of
No. 13 is known. As examples in which the number of lenses is four, see JP-A-6-67092 and JP-A-7-225.
No. 337, JP-A-8-220433, JP-A-8-220435, and JP-A-8-338946 are known.

[0003]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No.
The zoom lens disclosed in Japanese Patent Publication No. 13 has a small zoom ratio of about 2.3 times. JP-A-6-67092, JP-A-7-670
No. 225337, JP-A-8-220433, JP-A-8-220435
The zoom lens disclosed in Japanese Patent Application Laid-Open No. 8-338946 also has a zoom ratio of about 2.8 at the maximum. As described above, a zoom lens having a high zoom ratio exceeding, for example, three times has not been designed.

The present invention has been made in view of such a situation, and for example, a high zoom ratio with a small number of lenses, such as a case where the number of lenses is 4 to 5 and the zoom ratio exceeds 3 times. It is an object to provide a zoom lens having:

[0005]

The zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a stop, and a second group having a negative refractive power. First
The group includes a negative lens and a positive lens, and the second group having the negative refractive power includes a positive lens and a negative lens, and satisfies the condition (1).

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end and fw is the focal length at the wide-angle end. Further, another zoom lens according to the present invention includes, in order from the object side, a first group having a positive refractive power, a brightness stop, and a second group having a negative refractive power. The second group of negative refracting power is composed of a negative lens and a positive lens, and the second group of negative refracting power is composed of two lenses having a positive combined refracting power and a negative lens, and satisfies the condition (1).

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. Further, another zoom lens according to the present invention includes, in order from the object side, a first unit having a positive refractive power, a second unit having a negative refractive power, and a third unit having a negative refractive power. It is characterized by satisfaction.

(2) 2.5 <ft / fw <5.5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. Further, another zoom lens according to the present invention includes, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a negative refractive power. Movable at the time of magnification, the first group having the positive refractive power includes a negative lens and a positive lens, the second group having the negative refractive power includes a positive lens and a negative lens, and the third group having the negative refractive power. Is negative lens 1
It is characterized by being constituted by sheets.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first configuration of a zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a brightness stop, and a second group having a negative refractive power. The first group includes a negative lens and a positive lens, and the second group includes a positive lens and a negative lens, and satisfies the condition (1).

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. In order to achieve a zoom lens having a high zoom ratio with a small number of lenses in a two-group zoom lens having positive and negative refractive powers, in order from the object side, a first group of a negative lens and a positive lens, It is desirable to include a brightness stop and a second group of a positive lens and a negative lens. Condition (1)
Is a condition for achieving a zoom lens having a high zoom ratio. If the lower limit of 3 of the condition (1) is exceeded, the zoom ratio becomes small. On the other hand, when the value exceeds the upper limit of 5, it becomes difficult to correct aberrations from the wide-angle end to the telephoto end, so that good imaging performance cannot be obtained.

Further, even within the range satisfying the condition (1), the position of the light beam passing through each lens is greatly different between the wide-angle end and the telephoto end as the magnification ratio increases. In this case, in particular,
The problem is to correct off-axis aberrations at the wide-angle end and spherical aberrations at the telephoto end. Therefore, in the present invention, the off-axis aberration at the wide-angle end is reduced by arranging lenses such as a negative lens, a positive lens, an aperture, a positive lens, and a negative lens so that the left and right refractive powers are symmetrical across the aperture. Corrected well.

A second configuration of the zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a stop, and a second group having a negative refractive power. The first group includes a negative lens and a positive lens, and the second group having the negative refractive power includes two lenses having a combined refractive power of positive and a negative lens, and satisfies the condition (1). .

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. In the second configuration, in order to achieve a zoom lens having a high zoom ratio with a small number of lenses in a two-group zoom lens having positive and negative refractive powers, the first group having a positive refractive power is referred to as a negative lens. Although the second lens unit having a negative refractive power is composed of a positive lens, the second lens unit is composed of two lenses having a positive combined refractive power and a negative lens. As described above, by dividing the positive lens disposed on the diaphragm side into two positive lenses, off-axis aberration at the wide-angle end generated by the final negative lens can be favorably corrected.

A third configuration of the zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a negative refractive power. It satisfies (2).

(2) 2.5 <ft / fw <5.5 where ft is the focal length at the telephoto end and fw is the focal length at the wide-angle end. In the above-described first and second configurations, the first unit has a positive refractive power, and the second unit has a negative refractive power. In the third configuration, the second unit is further divided into two. The zoom lens is divided into three groups and has a positive / negative / negative refractive power, so that the total length of the lens at the telephoto end is short and a more compact zoom lens is achieved. In order to shorten the total length at the telephoto end, it is necessary to increase the power of each group. However, if the power of each group is increased, the field curvature generated by the negative lens (or the negative lens group) increases, and The surface falls in the direction away from the object. Therefore, in the present invention, the refractive power is positive.
By dispersing the power of the lens unit having a negative refracting power with a negative and negative three-group configuration, the amount of curvature of field is reduced.

The condition (2) is a condition for achieving a zoom lens having a high zoom ratio. If the lower limit of 2.5 of the condition (2) is exceeded, the zoom ratio will decrease. On the other hand, when the value exceeds the upper limit of 5.5, it becomes difficult to correct aberrations, so that good imaging performance cannot be obtained.

A fourth configuration of the zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a negative refractive power. Is also movable at the time of zooming, the first group of the positive refractive power is composed of a negative lens and a positive lens, the second group of the negative refractive power is composed of a positive lens and a negative lens, The third group is a negative lens 1
It is composed of sheets.

In a three-group configuration having positive, negative and negative refractive powers,
In order to achieve a high zoom ratio with a small number of lenses, a first lens unit of a negative lens and a positive lens, an aperture stop, a second lens unit of a positive lens and a negative lens, and a negative lens It is desirable to constitute the third group. In order to satisfactorily correct off-axis aberrations, it is preferable that the first and second units have a lens arrangement symmetrical with respect to the stop. In addition, by configuring the third unit with one negative lens having a low refractive power, it is possible to satisfactorily correct field curvature.

A fifth configuration of the zoom lens according to the present invention comprises, in order from the object side, a first unit having a positive refractive power, a diaphragm, and a second unit having a negative refractive power. The second group is composed of a lens and a positive lens, and the second group is composed of a positive lens and a negative lens. The second group is moved to the image plane side to perform focusing on a close object.

As described above, in a two-unit configuration having positive and negative refractive powers, in order to achieve a high zoom ratio zoom lens with a small number of lenses, the first lens of the negative lens and the positive lens must be arranged in order from the object side.
It is desirable that the optical system be composed of a group, a brightness stop, and a second group of a positive lens and a negative lens. In order to achieve a particularly compact zoom lens, it is desirable to perform focusing on a close object by moving the second unit to the image plane side. If focusing is performed by moving the first lens group,
In focusing on a close object, the first lens unit is moved to the object side, so that the total length at the telephoto end becomes particularly long. On the other hand, if the second lens unit is used for focusing, the total length of the telephoto end does not become longer, and there is also an advantage that aberration variation during focusing is small.

A sixth configuration of the zoom lens according to the present invention comprises, in order from the object side, a first group having a positive refractive power, a stop, and a second group having a negative refractive power. The first group is a negative lens. And the second lens unit is composed of a positive lens and a negative lens.
The positive lens of the first group has two aspheric surfaces.

In order to achieve a zoom lens having a large zoom ratio in a two-unit configuration having positive and negative refractive powers, it is necessary to satisfactorily correct negative spherical aberration particularly occurring at the telephoto end. Therefore, it is desirable that the positive lens of the first group has an aspheric surface on both sides. Since this positive lens is arranged near the aperture stop, the effect of correcting spherical aberration is large. In addition, having both surfaces aspherical also has an advantage of being resistant to manufacturing variations. Further, it is desirable that at least one surface has an aspherical shape such that the positive refractive power becomes weaker from the optical axis toward the periphery. With such a shape, it is possible to favorably correct negative spherical aberration particularly occurring at the telephoto end. In the above-described first to fifth configurations, by using at least one aspheric surface for the first group, aberrations can be favorably corrected.

In the first to sixth configurations, in order to favorably correct spherical aberration at the telephoto end, the power of each unit is weakened by increasing the total length at the telephoto end.
It is effective to reduce the spherical aberration generated in one group. Therefore, it is desirable that the lens system of the present invention satisfies the condition (3).

(3) 0.5 <Lt / ft <1.0 where Lt is the total length of the lens at the telephoto end, and ft is the focal length at the telephoto end. Condition (3) defines the range in which spherical aberration can be favorably corrected using the entire length at the telephoto end (the length from the first lens surface closest to the object side to the image plane). If the lower limit of 0.5 is exceeded, the power of each lens unit becomes strong, making it difficult to satisfactorily correct spherical aberration at the telephoto end. On the other hand, when the value exceeds the upper limit of 1.0, the total length of the zoom lens becomes long, and it is difficult to achieve a compact lens system. In addition, the spherical aberration of the lens system is better corrected,
In addition, for compactness, it is desirable to satisfy the following condition (3-1).

(3-1) 0.6 <Lt / ft <0.9 In order to better correct spherical aberration at the telephoto end in the two-unit zoom lens, the following condition (3-2) must be satisfied. It is more desirable to do.

(3-2) 0.78 <Lt / ft <0.
9 In the three-unit zoom lens, it is preferable that the following condition (3-3) is satisfied in order to more effectively correct spherical aberration at the telephoto end.

(3-3) 0.65 <Lt / ft <0.
78 In the first to sixth configurations, it is preferable that the following condition (4) is satisfied.

(4) 0.08 <f1 / ft <0.35 where f1 is the focal length of the first lens unit, and ft is the focal length at the telephoto end. Condition (4) is a condition for favorably correcting aberrations. If the lower limit of 0.08 is exceeded, the refractive power of the first lens unit becomes strong, and it is particularly difficult to favorably correct spherical aberration at the telephoto end. Becomes On the other hand, when the value exceeds the upper limit of 0.35, the refractive power of the first lens unit becomes weak, and in particular, the total length at the telephoto end becomes longer. In order to better correct the aberration of the lens system and shorten the total length at the telephoto end, it is desirable to satisfy the following condition (4-1).

(4-1) 0.12 <f1 / ft <0.25 In the first, second, fifth, and sixth configurations, it is preferable that the following condition (5) is satisfied.

(5) -0.3 <f22 / ft <-0.
05 Here, f22 is the focal length of the second group of the two-unit zoom lens, and ft is the focal length at the telephoto end.

Condition (5) is a condition for favorably correcting aberrations in a two-unit zoom lens. If the lower limit of -0.3 is exceeded, the refractive power of the second lens unit becomes weak, and in particular, the total length at the telephoto end becomes longer, which is not preferable. On the other hand, when the value exceeds the upper limit of -0.05, the refractive power of the second unit becomes strong, and it becomes difficult to satisfactorily correct spherical aberration particularly at the telephoto end. In order to better correct the spherical aberration of the lens system and shorten the total length at the telephoto end, the following condition (5-
It is desirable to satisfy 1).

(5-1) −0.22 <f22 / ft <−0.08 In order to achieve a compact zoom lens in the third and fourth configurations, the third lens unit must be placed on the image plane side. It is desirable to perform focusing on a nearby object by moving the object. It is also possible to focus on a close object by moving not only the third lens unit but also the other lens units. However, for a compact zoom lens, only the third lens unit is moved to the image plane side. It is desirable to make it.

In the first to sixth configurations described above, the following condition (6) must be satisfied in order to obtain sufficient design performance and to maintain performance during manufacturing. Is desirable.

(6) 4 <Lt / IH <8 where Lt is the total length of the lens at the telephoto end, and IH is the image height. FIG. 1 is a conceptual diagram of a zoom lens according to the present invention. In the figure, 1 is a zoom lens of the present invention, 2 is a mirror frame of the zoom lens 1, 3 is an off-axis principal ray, and 4 is an optical axis. FIG. 1 shows the state of the lens at the telephoto end. At the telephoto end, it is necessary to increase the distance from the final surface of the zoom lens to the image plane. Therefore, the lens is located at the tip (object side) of the lens frame of the zoom lens as shown in FIG. In this case, since the load is concentrated on the distal end side of the lens frame, the lens frame is easily deformed. That is, as the total lens length Lt at the telephoto end becomes longer with respect to the image height IH, the rate at which the lens frame is deformed by the weight of the zoom lens 1 increases, so that it becomes difficult to obtain good imaging performance. In order to suppress the deformation, the total lens length Lt at the telephoto end may be reduced with respect to the image height IH. However, in order to reduce the total lens length Lt at the telephoto end, the refractive power of each unit must be increased. Then, it becomes difficult to satisfactorily correct the aberration with a small number of lenses.

Therefore, it is desirable that the positive / negative two-group or the positive / negative / negative three-group zoom lens of the present invention satisfies the condition (6). If the lower limit of 4 is exceeded, it becomes difficult to satisfactorily correct aberrations with a small number of lenses. On the other hand, when the value exceeds the upper limit of 8, the deformation of the lens frame becomes large, and good imaging performance cannot be obtained. In order to configure the lens frame with a small number of lenses while suppressing deformation of the lens barrel, the condition (6)
It is desirable to satisfy -1).

(6-1) 4.8 <Lt / IH <7.2 Further, in the above-described first to sixth configurations, it is desirable that the following condition (7) is satisfied.

(7) 0.8 <f1 / IH <1.8 where f1 is the focal length of the first lens unit and IH is the image height.
Condition (7) is a condition for favorably correcting aberration.
If the lower limit of 0.8 is exceeded, the refractive power of the first lens group will increase,
In particular, it becomes difficult to satisfactorily correct off-axis aberrations at the wide-angle end and spherical aberrations at the telephoto end. If the upper limit of 1.8 is exceeded, the total length at the telephoto end becomes particularly long, which is not preferable. In order to better correct off-axis aberrations at the wide-angle end and spherical aberrations at the telephoto end and to shorten the overall length at the telephoto end, it is desirable to satisfy the following condition (7-1).

(7-1) 1 <f1 / IH <1.5 In the first, second, fifth, and sixth configurations, it is preferable that the following condition (8) is satisfied.

(8) -1.5 <f22 / IH <-0.
5 where f22 is the focal length of the second group of the two-unit zoom lens, and IH is the image height. Condition (8) is a condition for favorably correcting aberration. When the lower limit of -1.5 is exceeded,
In particular, the total length on the short telephoto side is undesirably long. On the other hand, when the value exceeds the upper limit of -0.5, the refractive power of the second lens unit becomes strong, and it becomes difficult to satisfactorily correct off-axis aberrations particularly at the wide-angle end. In order to favorably correct off-axis aberrations at the wide-angle end and to shorten the overall length at the telephoto end, the following condition (8-
It is desirable to satisfy 1).

(8-1) -1.3 <f22 / IH <-
0.8 In the third and fourth configurations, it is desirable that the following condition (9) is satisfied.

(9) -2.8 <f23 / IH <-1 where f23 is the focal length of the second group of the three-unit zoom lens, and IH is the image height. The condition (9) is a condition for favorably correcting aberration. If the upper limit of the condition (9) is exceeded, the refractive power of the second lens unit becomes strong, and it becomes difficult to favorably correct off-axis aberration particularly at the wide-angle end. On the other hand, exceeding the lower limit is not preferable because the total length at the telephoto end is particularly long. In order to favorably correct off-axis aberrations at the wide-angle end and shorten the overall length at the telephoto end, it is desirable to satisfy the following condition (9-1).

(9-1) −2.5 <f23 / IH <−
1.4 Examples will be described below. (Embodiment 1) A sectional view of the zoom lens of Embodiment 1 is shown in FIG.
FIG. 14 shows aberration diagrams. In the aberration diagram, SA
Denotes spherical aberration, AS denotes astigmatism, DT denotes distortion, CC denotes chromatic aberration of magnification, and TA denotes off-axis lateral aberration. The wavelength of the d line is 587.56 nm, the wavelength of the C line is 656.27 nm, and the wavelength of the F line is 486.
13 nm. These items are described in Example 2 below.
The same applies to the twelfth to twelfth embodiments.

The first embodiment is a zoom lens having a focal length of 38.9 mm to 127.3 mm and a zoom ratio of 3.27 although the number of lenses is as small as four. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power.
The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

In the present embodiment, off-axis aberrations, especially at the wide-angle end, are favorably corrected by arranging lenses so that the refractive power is symmetrical with respect to the stop. The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the positive lens of the second group has a biconvex shape, and the negative lens has a meniscus shape with the concave surface facing the object side. Has become. Note that the positive lens of the second group favorably corrects chromatic aberration of magnification.
A PC (polycarbonate) which is a high dispersion optical element is used.

The aspherical surfaces are used on the object side surface of the first group negative lens and on both surfaces of the positive lens, and on the object side surface of the second group positive lens. In the zoom lens of the present embodiment,
Large off-axis aberrations occur in the positive lens with relatively high refractive power located closer to the object side than the stop, and especially in the negative lens closest to the image located at the position where the ray height at the wide-angle end increases. There is a tendency. In particular, the amount of coma and distortion is large. Therefore, the aspherical surface used for the negative lens of the first group is shaped so that the refractive power of the negative lens becomes strong in the peripheral portion, and thereby, coma and distortion are satisfactorily corrected. The same effect is obtained by forming the aspherical surface used for the positive lens of the second group such that the refractive power of the lens becomes strong at the peripheral portion.

Focusing on a close object is the second
By moving the group to the image side, the total length of the lens at the telephoto end is shortened. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

The zoom lens of this embodiment can be used for an optical system using a film such as a silver halide film. Further, the present invention can be applied to an optical system using an image sensor such as a CCD or a CMOS.

Example 2 FIG. 3 is a cross-sectional view of the zoom lens of Example 2, and FIG. 15 is an aberration diagram. The second embodiment is a zoom lens having four lenses as in the first embodiment. The focal length is 39.2 mm to 150.4 mm, and the zoom ratio is 3.84. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

Also in this embodiment, the off-axis aberration at the wide-angle end is particularly well corrected by arranging the lenses such that the refractive power is symmetrical with respect to the stop. The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the positive lens of the second group has a biconvex shape, and the negative lens has a meniscus shape with the concave surface facing the object side. Has become. The second
The positive lens of the group uses a PC (polycarbonate) which is a high-dispersion optical element in order to satisfactorily correct chromatic aberration of magnification.

The aspherical surfaces are used on the object side surface of the first group negative lens and both surfaces of the positive lens, and on the object side surface of the second group positive lens. Focusing on a close object is performed by moving the second unit to the image side, thereby realizing a reduction in the overall length of the lens at the telephoto end. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment also satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied. (Embodiment 3) A sectional view of a zoom lens according to Embodiment 3 is shown in FIG.
FIG. 16 shows aberration diagrams. The third embodiment is a zoom lens having four lenses as in the first embodiment. The focal length is from 32.9 mm to 154 mm, and the zoom ratio is 4.68. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group, in order from the object side,
The second lens unit includes a negative lens and a positive lens, and the second unit includes a positive lens and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

Also in this embodiment, the off-axis aberration at the wide-angle end is particularly well corrected by arranging the lenses such that the refractive power is symmetrical with respect to the stop. The negative lens of the first group has a biconcave shape, the positive lens has a biconvex shape, the positive lens of the second group has a meniscus shape with the convex surface facing the image side, and the negative lens has a meniscus shape with the concave surface facing the object side. Has become. The second
The positive lens of the group uses a PC (polycarbonate) which is a high-dispersion optical element in order to satisfactorily correct chromatic aberration of magnification.

The aspherical surface is used for the object side surface of the negative lens of the first group and both surfaces of the positive lens, and the object side surface of the positive lens of the second group and the object side surface of the negative lens. Focusing on a close object is performed by moving the second unit to the image side, thereby realizing a reduction in the overall length of the lens at the telephoto end. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens of the present embodiment also has the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied. Embodiment 4 FIG. 5 is a sectional view of a zoom lens according to Embodiment 4.
FIG. 17 shows aberration diagrams. The fourth embodiment is also a zoom lens having four lenses, as in the first embodiment. The focal length is from 37.8 mm to 180.5 mm, and the zoom ratio is 4.78. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

Also in this embodiment, the off-axis aberration at the wide-angle end is particularly well corrected by arranging the lenses such that the refractive power is symmetrical with respect to the stop. The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the positive lens of the second group has a biconvex shape, and the negative lens has a meniscus shape with the concave surface facing the object side. Has become. The second
The positive lens of the group uses a PC (polycarbonate) which is a high-dispersion optical element in order to satisfactorily correct chromatic aberration of magnification.

The aspherical surface is used for the object-side surface of the negative lens of the first group and the image-side surface of the positive lens, and the object-side surface of the positive lens of the second group. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens of the present embodiment also satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

(Embodiment 5) A sectional view of the zoom lens of Embodiment 5 is shown in FIG. 6, and an aberration diagram is shown in FIG. The fifth embodiment is a zoom lens having four lenses as in the first embodiment. The focal length is 39.2 mm to 151.3 mm, and the zoom ratio is 3.86. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

Also in this embodiment, the off-axis aberration at the wide-angle end is particularly well corrected by arranging the lenses such that the refractive power is symmetrical with respect to the stop. The negative lens in the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the positive lens in the second group has a meniscus shape with the concave surface facing the object side, and the negative lens has a concave surface facing the object side. It has a meniscus shape toward. No PC (polycarbonate) is used in the lens of this embodiment.

The aspheric surface is used for the object side surface of the first group negative lens and both surfaces of the positive lens, and the object side surface of the second group positive lens. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment also satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

(Embodiment 6) FIG. 7 is a sectional view of the zoom lens according to Embodiment 6, and FIG. 19 is an aberration diagram. Example 6 is a zoom lens having five lenses. Focal length 39.0mm
From 150.5 mm, and the zoom ratio is 3.86. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens, a positive lens, and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

In the first embodiment, the positive lens component of the second group is composed of one lens. However, in the zoom lens of the present embodiment, the positive lens component of the second group is composed of two lenses. This is the feature. In the first embodiment, a PC (Polycarbonate) is used for the positive lens of the second group. However, PC also has a disadvantage that birefringence is likely to occur, and as a result, imaging performance is deteriorated. Therefore, in the present embodiment, the positive lens of the second group is constituted by two positive lenses, and P
The influence of birefringence is reduced by reducing the thickness of one positive lens using C.

The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, and the negative lens of the second group has
The first positive lens has a meniscus shape with the concave surface facing the image side, the second positive lens has a biconvex shape, and the negative lens has a meniscus shape with the concave surface facing the object side.

The aspheric surface is used for the object-side surface of the negative lens of the first group and both surfaces of the positive lens, and for the object-side surface of the first positive lens of the second group. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. The first
Although it is possible to focus on a close object by moving the group to the object side, it is difficult to shorten the total length of the lens at the telephoto end as in the case where the second group is moved to the image side. .

The zoom lens according to the present embodiment also has the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

(Embodiment 7) FIG. 8 is a sectional view of the zoom lens according to Embodiment 7, and FIG. Embodiment 7 is a zoom lens having five lenses as in Embodiment 6.
The focal length is 38.9mm to 151.4mm, and the zoom ratio is 3.
89. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a negative lens, a positive lens, and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

In this embodiment, the positive lens component of the second group is composed of two lenses. However, unlike the sixth embodiment, the positive lens component of the second group is composed of a negative lens and a positive lens. I have. Since the thickness of the negative lens is small as in the case of the sixth embodiment, the influence of birefringence can be suppressed.

The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the negative lens of the second group has a biconcave shape, the positive lens has a biconvex shape, and the negative lens has a It has a meniscus shape with the concave surface facing the object side.

The aspheric surfaces are used on the object side surface of the first group negative lens and on both surfaces of the positive lens, and on the object side surface of the second group biconcave negative lens. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment also has the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

(Embodiment 8) FIG. 9 is a sectional view of the zoom lens according to Embodiment 8, and FIG. 21 is an aberration diagram. Embodiment 8 is also a zoom lens having five lenses as in Embodiment 6.
The focal length is 39.3mm to 150.4mm, and the zoom ratio is 3.
83. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a positive lens, a negative lens, and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group. In this embodiment, the positive lens component of the second group is composed of two lenses, that is, a positive lens and a negative lens, and substantially the same effects as in the sixth embodiment are obtained.

The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a biconvex shape, the positive lens of the second group has a biconvex shape, and the negative lens has a concave surface facing the object side. The meniscus shape and the negative lens have a meniscus shape with the concave surface facing the object side.

The aspheric surface is used for the object side surface of the first group negative lens and both surfaces of the positive lens, and the object side surface of the second group positive lens. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment also satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

Ninth Embodiment FIG. 10 is a sectional view of a zoom lens according to a ninth embodiment, and FIG. 22 is an aberration diagram thereof. The ninth embodiment is also a zoom lens having five lenses as in the sixth embodiment. The focal length is from 39.2 mm to 150.5 mm, and the zoom ratio is 3.84. In order from the object side, it is composed of a first group having a positive refractive power and a second group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens, and the second group includes a negative lens, a positive lens, and a negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group. In this embodiment, the positive lens component of the second group is composed of two lenses, a positive lens and a negative lens. However, no PC (Polycarbonate) is used and glass is used.

The negative lens of the first group has a meniscus shape with the concave surface facing the image side, the positive lens has a plano-convex shape, the negative lens of the second group has a meniscus shape with the concave surface facing the image side, and the positive lens has a concave surface. Has a meniscus shape with the concave surface facing the object side, and the negative lens has a meniscus shape with the concave surface facing the object side.

The aspheric surface is used for the object side surface of the first group negative lens and both surfaces of the positive lens, and the object side surface of the second group negative lens. In addition, by moving the second unit to the image side, focusing on a close object is performed, and the total length of the lens at the telephoto end can be reduced. It is also possible to focus on a close object by moving the first unit to the object side. However, as in the case where the second unit is moved to the image side, the total length of the lens at the telephoto end should be shortened. It is difficult.

The zoom lens according to the present embodiment also satisfies the condition (1),
(3), (3-1), (3-2), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (8) and (8-1) are satisfied.

(Embodiment 10) FIG. 11 is a sectional view of the zoom lens according to Embodiment 10, and FIG. Example 1
0 means that the number of lenses is as small as 5 but the focal length is 39.1
The zoom lens has a zoom ratio of 4.00 mm to 156.3 mm and a magnification ratio of 4.00. In order from the object side, it is composed of a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a negative refractive power. The first group includes, in order from the object side, a negative lens and a positive lens. The second group includes a positive lens and a negative lens.
The group consists of one negative lens. The aperture is the first
It is arranged between the group and the second group and is integral with the first group.

The zoom lens of the tenth embodiment is a three-unit lens system, and is obtained by further dividing the second group having a negative refractive power of the first to ninth embodiments into two groups. By using two negative refractive power lens groups, it becomes possible to reduce the amount of aberration generated as compared with the case where there is one negative refractive power lens group. With such a configuration, the refracting power of each group can be increased, and in particular, the total length on the telephoto side can be reduced.
Further, it is possible to satisfactorily correct a wide-side field curvature generated by a lens unit having a negative refractive power.

The negative lens of the first group has a biconcave shape, the positive lens has a biconvex shape, the positive lens of the second group has a meniscus shape with the concave surface facing the object side, and the negative lens has the concave surface facing the object side. The negative lens of the third group has a meniscus shape with the concave surface facing the object side. The positive lens of the second group uses a PC (polycarbonate) which is a high-dispersion optical element in order to satisfactorily correct lateral chromatic aberration.

The aspherical surface is used for both the object side surface of the first group negative lens and both surfaces of the positive lens, and the both surface of the second group positive lens and the image side surface of the negative lens. Focusing on the closest object is performed by moving the third lens unit to the image side, thereby shortening the overall length of the lens at the telephoto end. It is also possible to perform focusing on a close object by moving the first lens unit to the object side.
It is difficult to shorten the entire length of the lens at the telephoto end as in the case where the group is moved to the image side.

The zoom lens according to the present embodiment satisfies the condition (1),
(3), (3-1), (3-3), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (9), and (9-1) are satisfied.

(Embodiment 11) FIG. 12 is a sectional view of the zoom lens according to Embodiment 11, and FIG. Example 1
1 is a zoom lens having a focal length of 39.1 mm to 154.0 mm and a zoom ratio of 3.94, although the number of lenses is as small as 5 as in the tenth embodiment. In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a negative refractive power. The first group, in order from the object side,
The second group is composed of a positive lens and a negative lens, and the third group is composed of one negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

The negative lens in the first group has a biconcave shape, the positive lens has a biconvex shape, the positive lens in the second group has a meniscus shape with the concave surface facing the object side, and the negative lens has the concave surface facing the object side. The negative lens of the third group has a meniscus shape with the concave surface facing the object side.

The aspherical surface is used for the object side surface of the first group negative lens and both surfaces of the positive lens, and the object side surface of the second group positive lens and the image side surface of the negative lens. Focusing on the closest object is performed by moving the third lens unit to the image side, thereby shortening the overall length of the lens at the telephoto end. It is also possible to perform focusing on a close object by moving the first lens unit to the object side,
It is difficult to shorten the entire length of the lens at the telephoto end as in the case where the third unit is moved to the image side.

The zoom lens according to the present embodiment satisfies the condition (1),
(3), (3-1), (3-3), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (9), and (9-1) are satisfied.

Example 12 FIG. 13 is a sectional view of the zoom lens of Example 12, and FIG. 25 is an aberration diagram thereof. Example 1
1 is a zoom lens having a focal length of 39.0 mm to 180.7 mm and a zoom ratio of 4.63 although the number of lenses is as small as 5 as in the tenth embodiment. In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a negative refractive power. The first group, in order from the object side,
The second group is composed of a positive lens and a negative lens, and the third group is composed of one negative lens. The aperture is disposed between the first and second groups, and is integrated with the first group.

The negative lens of the first group is biconcave, the positive lens is biconvex, the positive lens of the second group is meniscus with the concave surface facing the object side, the negative lens is biconcave, and the third group is Has a meniscus shape with the concave surface facing the object side.

The aspheric surface is used for both the object side surface of the first group negative lens and both surfaces of the positive lens, and the both surface of the second group positive lens and the image side surface of the negative lens. Focusing on the closest object is performed by moving the third lens unit to the image side, thereby shortening the overall length of the lens at the telephoto end. It is also possible to perform focusing on a close object by moving the first lens unit to the object side.
It is difficult to shorten the entire length of the lens at the telephoto end as in the case where the group is moved to the image side.

The zoom lens according to the present embodiment satisfies the condition (1),
(3), (3-1), (3-3), (4), (4-
1), (5), (5-1), (6), (6-1),
(7), (7-1), (9), and (9-1) are satisfied.

The numerical data of each of the above embodiments is shown below. In addition to the symbols, f is the focal length of the entire system, F _NO is F
Number, 2ω is angle of view, FB is back focus,
r _1, r ₂ ... curvature radius of each lens surface, d _1, d ₂ ... the spacing between the lens surfaces, n _1, n ₂ ... d-line refractive index of each lens, ν _1, ν ₂ ... Is the Abbe number of each lens. The aspherical shape is approximated by the following equation, where Z is the optical axis direction and Y is the direction perpendicular to the optical axis.

Z = (Y ² / r) / [1+ [1- (K + 1) · (Y
^{/ R) 2] 1/2] +} A 4 Y 4 + A 6 Y 6 + A 8 Y 8 + A 10 Y 10 + A 12 Y 12 + ... However, K is a conic _{constant, A 4, A 6, A} 8, A 10, A ₁₂ ,... Are the fourth, sixth, eighth, tenth, twelfth,. In the display of the value of the aspheric coefficient, for example, 1.000e-080 is 1.000 × 10 ⁻⁸ .

[0096] (Example ₁₎ r 1 = 34.412 _{(aspherical) d 1 = 1.300 n 1 =} 1.84666 ν 1 = 23.78 r 2 = 24.466 d 2 = 8.507 r 3 = 149.580 ( aspherical) d ₃ = 3.706 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -13.012 (aspheric) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 63.626 (aspheric) d ₆ = 7.380 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -181.335 d ₇ = 3.940 r ₈ = -13.142 d ₈ = 1.100 n ₄ = 1.88300 ν ₄ = 40.76 r ₉ = -113.168 Aperture surface 5 Aspheric surface first surface k = 0.0000 A ₄ = -5.8569e-005 A ₆ = -4.7161e-007 A ₈ = 6.6160e-010 A ₁₀ = -3.3650e-011 A ₁₂ = 0.0000 Surface 3 k = 0.0000 A ₄ = 3.5811e-006 A ₆ = -7.7667e-008 A ₈ = 1.2825 e-008 A ₁₀ = -2.2329e-010 A ₁₂ = 0.0000 4th surface k = 0.0000 A ₄ = 1.9803e-005 A ₆ = 2.6641e-007 A ₈ = 2.1700e-009 A ₁₀ = -5.7050e-011 A ₁₂ = -7.5632e-013 Surface 6 k = 0.0000 A ₄ = 3.5476e-005 A ₆ = 4.3353e-007 A ₈ = -6.1066e-009 A ₁₀ = 3.8966e-011 A ₁₂ = 1.9239e-014 Zoom data Wide-angle end Middle telephoto end f (mm) 38.901 72.050 127.347 F _NO 5.767 9.178 11.669 2 ω (°) 56.5 32.9 19.2 FB (mm) 9.686 37.196 83.085 D1 13.001 4.720 0.500

(Example 2) r ₁ = 31.210 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 24.336 d ₂ = 9.971 r ₃ = 66.580 (aspherical surface) d ₃ = 4.088 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -14.698 (aspherical surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 248.286 (aspherical surface) d ₆ = 6.443 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -115.040 d ₇ = 4.617 r ₈ = -11.804 d ₈ = 1.000 n ₄ = 1.81600 ν ₄ = 46.62 r ₉ = -52.358 Aperture surface 5 Aspherical surface first surface k = 0.0000 A ₄ = -4.0530e-005 A ₆ = -3.4031e-007 A ₈ = 1.5731e-009 A ₁₀ = -2.2578e-011 A ₁₂ = 0.0000 Surface 3 k = 0.0000 A ₄ = -4.8646e-006 A ₆ = 4.9390e-007 A ₈ =- 8.3689e-009 A ₁₀ = 1.1800e-011 A ₁₂ = 0.0000 Surface 4 k = 0.0000 A ₄ = 1.5019e-005 A ₆ = 6.6259e-007 A ₈ = -1.0607e-008 A ₁₀ = 3.4652e-011 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 4.3210e-005 A ₆ = 3.4596e-007 A ₈ = -2.8775e-009 A ₁₀ = 2.2623e-011 A ₁₂ = 0.0000 Zoom data Wide angle end Middle Tele end f (mm) 39.202 76.011 150.400 F _no 5.664 9.440 12.643 2ω (°) 5 6.4 31.5 16.3 FB (mm) 9.315 39.491 100.477 D1 12.760 4.730 0.500

(Example 3) r ₁ = −436.607 (aspheric surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 227.852 d ₂ = 11.027 r ₃ = 30.765 (aspheric surface) d ₃ = 3.710 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -17.530 (aspherical surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = -104.078 (aspherical surface) d ₆ = 7.841 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -43.433 d ₇ = 4.755 r ₈ = -10.965 (aspherical surface) d ₈ = 1.000 n ₄ = 1.81600 ν ₄ = 46.62 r ₉ = -76.194 Aperture surface 5 Aspherical coefficient first surface k = 0.0000 A ₄ =- 3.2879e-005 A ₆ = -3.2615e-007 A ₈ = 7.7064e-009 A ₁₀ = -1.1020e-010 A ₁₂ = 5.4419e-013 Surface 3 k = 0.0000 A ₄ = 4.5993e-005 A ₆ = -4.4329e-007 A ₈ = 5.0842e-008 A ₁₀ = -1.5638e-009 A ₁₂ = 1.4797e-011 Surface 4 k = 0.0000 A ₄ = 7.2828e-005 A ₆ = 5.0120e-007 A ₈ = -9.5226e-010 A ₁₀ = -6.5117e-010 A ₁₂ = 9.8293e-012 Surface 6 k = 0.0000 A ₄ = 4.0295e-005 A ₆ = 9.8730e-007 A ₈ = -5.6098e-008 A ₁₀ = 1.0171e-009 A ₁₂ = -5.4281e-012 8th surface k = 0.0000 A ₄ = 2.0645e-005 A ₆ = 3.8173e-007 A ₈ = -1.4281e-008 A ₁₀ = 2.9853e-010 A ₁₂ = -1.2558e-012 Zoom data Wide-angle end Medium Telephoto end f (mm) 32.923 69.972 154.045 F _no 5.604 8.976 12.814 2ω (°) 65.1 33.8 15.9 FB (mm) 5.370 32.613 94.435 D1 11.377 3.985 0.400

(Example 4) r ₁ = 33.165 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 25.507 d ₂ = 9.038 r ₃ = 84.687 d ₃ = 3.672 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -13.524 (aspherical surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 202.330 (aspherical surface) d ₆ = 5.754 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -147.071 d ₇ = 4.578 r ₈ = -11.319 d ₈ = 1.000 n ₄ = 1.81600 ν ₄ = 46.62 r ₉ = -50.922 Aperture surface 5 Aspheric surface first surface k = 0.0000 A ₄ = -5.0672e-005 A ₆ = -4.0011e -007 A ₈ = 2.6261e-010 A ₁₀ = -2.4689e-011 A ₁₂ = -4.0538e-014 Side 4 k = 0.0000 A ₄ = 3.2167e-005 A ₆ = -8.2321e-007 A ₈ = 3.3440 e-008 A ₁₀ = -5.1746e-010 A ₁₂ = 2.9757e-012 Surface 6 k = 0.0000 A ₄ = 5.8786e-005 A ₆ = -6.8130e-007 A ₈ = 3.4194e-008 A ₁₀ =- 4.8569e-010 A ₁₂ = 2.4860e-012 Zoom data Wide angle end Middle telephoto end f (mm) 37.812 78.404 180.456 F _NO 5.947 9.730 15.051 2ω (°) 58.1 30.5 13.7 FB (mm) 8.587 40.791 121.752 D1 12.760 4.730 0.500

(Example 5) r ₁ = 25.194 (aspheric surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 21.272 d ₂ = 8.749 r ₃ = 724.954 (aspheric surface) d ₃ = 2.820 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -13.738 (aspherical surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = -193.212 (aspherical surface) d ₆ = 6.055 n ₃ = 1.59270 ν ₃ = 35.31 r ₇ = -40.974 d ₇ = 4.320 r ₈ = -12.861 d ₈ = 1.000 n ₄ = 1.77250 ν ₄ = 49.60 r ₉ = -76.771 Aperture surface 5 Aspheric surface first surface k = 0.0000 A ₄ = -4.7280e-005 A ₆ = -4.1474e-007 A ₈ = 7.9294e-010 A ₁₀ = -3.6676e-011 A ₁₂ = 0.0000 Third surface k = 0.0000 A ₄ = 1.3756e-006 A ₆ = 6.3039e-007 A ₈ =- 1.4996e-008 A ₁₀ = 1.3208e-010 A ₁₂ = 0.0000 Surface 4 k = 0.0000 A ₄ = 1.3559e-005 A ₆ = 3.9114e-007 A ₈ = -1.1426e-008 A ₁₀ = 1.0792e-010 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 4.1817e-005 A ₆ = -2.6374e-008 A ₈ = 3.0687e-009 A ₁₀ = -1.2486e-011 A ₁₂ = 0.0000 Zoom data Wide-angle end Middle Telephoto Edge f (mm) 39.163 79.442 151.266 F _no 5.439 9.850 12.651 2ω (°) 56 .1 30.2 16.3 FB (mm) 7.364 42.957 106.426 D1 17.025 5.880 0.734

(Example 6) r ₁ = 31.503 (aspheric surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 24.469 d ₂ = 9.391 r ₃ = 72.673 (aspheric surface) d ₃ = 3.583 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -14.288 (aspheric) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 165.865 (aspheric) d ₆ = 3.516 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = 285.957 d ₇ = 0.209 r ₈ = 320.577 d ₈ = 3.289 n ₄ = 1.63980 ν ₄ = 34.46 r ₉ = -84.201 d ₉ = 3.608 r ₁₀ = -11.567 d ₁₀ = 1.000 n ₅ = 1.81600 ν ₅ = 46.62 r ₁₁ = -63.623 Aperture surface 5 Aspheric coefficient First surface k = 0.0000 A ₄ = -4.6228e-005 A ₆ = -4.5135e-007 A ₈ = 2.6950e-009 A ₁₀ = -3.5769e-011 A ₁₂ = 0.0000 3rd side k = 0.0000 A ₄ = -1.1747e-006 A ₆ = 9.6673e-007 A ₈ = -1.6707e-008 A ₁₀ = 1.3859e-010 A ₁₂ = 0.0000 4th side k = 0.0000 A ₄ = 1.2694e -005 A ₆ = 1.1765e-006 A ₈ = -2.0045e-008 A ₁₀ = 1.6230e-010 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 4.7717e-005 A ₆ = 5.0593e-007 A _{8 = -5.2272e-009 A 10 = 4.0431e} -011 A 12 = 0.0000 zoom data wide-angle end in Telephoto end f (mm) 39.005 74.724 150.491 F NO 5.630 9.257 12.651 2ω (°) 56.5 31.9 16.3 FB (mm) 9.662 39.193 101.832 D1 12.800 4.863 0.500

(Example 7) r ₁ = 27.223 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 21.422 d ₂ = 8.515 r ₃ = 465.271 (aspherical surface) d ₃ = 2.820 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -13.309 (aspheric surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = -799.474 (aspheric surface) d ₆ = 3.032 n ₃ = 1.52542 ν ₃ = 55.78 r ₇ = 541.727 d ₇ = 0.323 r ₈ = 265.124 d ₈ = 3.071 n ₄ = 1.59270 ν ₄ = 35.31 r ₉ = -57.986 d ₉ = 4.348 r ₁₀ = -13.307 d ₁₀ = 1.200 n ₅ = 1.77250 ν ₅ = 49.60 r ₁₁ = -98.356 Aperture surface 5 Aspheric coefficient First surface k = 0.0000 A ₄ = -5.6401e-005 A ₆ = -3.7116e-007 A ₈ = -9.8762e-010 A ₁₀ = -2.9357e-011 A ₁₂ = 0.0000 3rd side k = 0.0000 A ₄ = 6.9849e-006 A ₆ = 8.9623e-007 A ₈ = -2.8392e-008 A ₁₀ = 3.2189e-010 A ₁₂ = 0.0000 4th side k = 0.0000 A ₄ = 1.1980 e-005 A ₆ = 8.0610e-007 A ₈ = -2.6150e-008 A ₁₀ = 2.9859e-010 A ₁₂ = 0.0000 Surface k = 0.0000 A ₄ = 3.9857e-005 A ₆ = -2.0990e-009 _{A 8 = 3.4748e-009 A 10} = -1.9074e-011 A 12 = 0.0000 zoom data wide Intermediate Telephoto end f (mm) 38.914 79.140 151.400 F NO 5.396 9.841 12.677 2ω (°) 56.5 30.3 16.2 FB (mm) 7.311 42.507 105.733 D1 16.897 5.867 0.774

Example 8 r ₁ = 48.416 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 36.969 d ₂ = 6.568 r ₃ = 360.833 (aspherical surface) d ₃ = 4.259 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -13.113 (aspheric) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 69.425 (aspheric) d ₆ = 2.705 n ₃ = 1.52542 ν ₃ = 55.79 r ₇ = -4699.789 d ₇ = 2.851 r ₈ = -15.594 d ₈ = 3.496 n ₄ = 1.78472 ν ₄ = 25.68 r ₉ = -15.974 d ₉ = 2.974 r ₁₀ = -10.881 d ₁₀ = 1.200 n ₅ = 1.72916 ν ₅ = 54.68 r ₁₁ = -45.630 Aperture surface 5 Aspheric surface first surface k = 0.0000 A ₄ = -6.0777e-005 A ₆ = -4.3568e-007 A ₈ = 2.7301e-009 A ₁₀ = -5.1618e-011 A ₁₂ = 0.0000 3rd surface k = 0.0000 A ₄ = 1.8211e-006 A ₆ = -6.1220e-007 A ₈ = 1.7366e-008 A ₁₀ = -5.8411e-010 A ₁₂ = 0.0000 4th surface k = 0.0000 A ₄ = 1.2980e-005 A ₆ = -4.4452e-007 A ₈ = 1.1146e-008 A ₁₀ = -3.7822e-010 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 7.0254e-005 A ₆ = 2.9806e- _{007 A 8 = -2.5591e-010 A} 10 = 4.3032e-011 A 12 = 0.0000 zoom data wide Intermediate Telephoto end f (mm) 39.324 76.131 150.398 F NO 5.483 9.145 12.537 2ω (°) 55.7 31.3 16.3 FB (mm) 7.596 38.973 102.285 D1 13.843 5.108 0.500

Example 9 r ₁ = 51.587 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 35.082 d ₂ = 6.196 r ₃ = 67032.480 (aspherical surface) d ₃ = 4.538 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -12.296 (aspherical surface) d ₄ = 0.500 r ₅ = INF d ₅ = D1 r ₆ = 133.140 (aspherical surface) d ₆ = 1.300 n ₃ = 1.80610 ν ₃ = 40.92 r ₇ = 66.082 d ₇ = 0.975 r ₈ = -191.803 d ₈ = 2.200 n ₄ = 1.80518 ν ₄ = 25.42 r ₉ = -78.635 d ₉ = 5.927 r ₁₀ = -10.737 d ₁₀ = 1.000 n ₅ = 1.69680 ν ₅ = 55.53 r ₁₁ = -30.399 Aperture surface 5 Aspheric coefficient First surface k = 0.0000 A ₄ = -6.8156e-005 A ₆ = -3.8295e-007 A ₈ = -1.0476e-009 A ₁₀ = -2.6471e-011 A ₁₂ = 0.0000 3rd surface k = 0.0000 A ₄ = -9.0861e-006 A ₆ = -1.2445e-006 A ₈ = 3.5837e-008 A ₁₀ = -8.9054e-010 A ₁₂ = 0.0000 4th surface k = 0.0000 A ₄ = 1.1350e-005 A ₆ = -8.1167e-007 A ₈ = 2.0180e-008 A ₁₀ = -5.0173e-010 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 4.0579e-005 A ₆ = 4.7325e -009 A ₈ = 2.0580e-009 A ₁₀ = -5.5734e-013 A ₁₂ = 0.0000 Zoom data f (m m) 39.240 74.386 150.490 F _NO 5.199 9.249 13.081 2ω (°) 56.1 32.0 16.3 FB (mm) 7.253 36.422 99.583 D1 15.865 7.470 2.730

Example 10 r ₁ = 1324.221 (aspheric surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 83.191 d ₂ = 5.657 r ₃ = 23.202 (aspheric surface) d ₃ = 7.147 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -18.660 (aspheric) d ₄ = 0.600 r ₅ = INF d ₅ = D1 r ₆ = -110.497 (aspheric) d ₆ = 4.401 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -21.993 (aspheric surface) d ₇ = 1.891 r ₈ = -18.131 d ₈ = 0.820 n ₄ = 1.777250 ν ₄ = 49.60 r ₉ = 142.753 (aspheric surface) d ₉ = D2 r ₁₀ = -11.379 d ₁₀ = 1.000 n ₅ = 1.72916 ν ₅ = 54.68 r ₁₁ = -19.539 Aperture surface 5 Aspherical surface first surface k = 0.0000 A ₄ = -6.5407e-005 A ₆ = -1.8351e-007 A ₈ = 3.6790e-010 A ₁₀ = -6.0018e-013 A ₁₂ = 0.0000 3rd surface k = 0.0000 A ₄ = 1.0216e-004 A ₆ = 5.3543e-007 A ₈ = -2.1427e-010 A ₁₀ = 4.3684e-011 A ₁₂ = 0.0000 4th Surface k = 0.0000 A ₄ = 9.3684e-005 A ₆ = 6.5275e-007 A ₈ = 6.6760e-009 A ₁₀ = -5.2586e-011 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 1.2967e-004 A ₆ = -2.3252e-007 A ₈ = 3.8509e-008 A ₁₀ = -6.1610e-010 A ₁₂ = 0.0000 7th Surface k = 0.0000 A ₄ = 2.8294e-004 A ₆ = -2.1285e-006 A ₈ = 7.8906e-008 A ₁₀ = -8.0943e-010 A ₁₂ = 0.0000 Surface 9 k = 0.0000 A ₆ = 2.0588 e-006 A ₈ = -3.0508e-008 A ₁₀ = 1.7406e-010 A ₁₂ = 0.0000 Zoom data Wide angle end Middle telephoto end f (mm) 39.101 72.374 156.257 F _NO 5.628 9.588 12.841 2ω (°) 55.6 32.5 15.7 FB ( mm) 6.458 27.027 84.665 D1 11.257 4.128 0.600 D2 5.076 9.617 9.915

(Example 11) r ₁ = -138.527 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 1051.531 d ₂ = 4.123 r ₃ = 31.953 (aspherical surface) d ₃ = 7.310 n ₂ = 1.48749 ν ₁ = 70.23 r ₄ = -16.206 (aspheric surface) d ₄ = 0.450 r ₅ = INF d ₅ = D1 r ₆ = -76.487 (aspheric surface) d ₆ = 6.921 n ₃ = 1.58423 ν ₁ = 30.49 r ₇ = -23.873 d ₇ = 2.179 r ₈ = -13.985 d ₈ = 0.989 n ₄ = 1.77250 ν ₁ = 49.60 r ₉ = -45.055 (aspheric) d ₉ = D2 r ₁₀ = -13.273 d ₁₀ = 1.000 n ₅ = 1.72916 ν ₁ = 54.68 r ₁₁ = -35.127 Aperture surface 5 Aspheric coefficient First surface k = 0.0000 A ₄ = -9.5528e-005 A ₆ = -1.5423e-007 A ₈ = -3.6986e-009 A ₁₀ = 6.6419 e-011 A ₁₂ = -4.0574e-013 Surface 3 k = 0.0000 A ₄ = 1.6097e-004 A ₆ = 3.1557e-007 A ₈ = 1.2419e-008 A ₁₀ = -1.5818e-010 A ₁₂ = 1.9274 e-012 4th surface k = 0.0000 A ₄ = 1.1140e-004 A ₆ = 5.7295e-007 A ₈ = 2.7356e-008 A ₁₀ = -5.2204e-010 A ₁₂ = 7.7406e-012 6th surface k = 0.0000 A ₄ = 4.2329e-005 A ₆ = 3.6554e-007 A ₈ = -5.1270e-009 A ₁₀ = 9.2108e-011 A ₁₂ = -4.0087e -013 9th surface k = 0.0000 A ₆ = -6.9621e-008 A ₈ = 2.5785e-009 A ₁₀ = -3.7926e-011 A ₁₂ = 1.5918e-013 Zoom data Wide-angle end Middle Telephoto end f (mm ) 39.109 73.897 153.999 F _NO 5.626 9.782 12.586 2ω (°) 55.7 31.7 15.9 FB (mm) 6.818 27.073 81.028 D1 10.778 2.983 0.500 D2 3.328 8.762 7.127

Example 12 r ₁ = −82.807 (aspherical surface) d ₁ = 1.200 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 1875.085 d ₂ = 5.030 r ₃ = 20.948 (aspherical surface) d ₃ = 9.430 n ₂ = 1.48749 ν ₂ = 70.23 r ₄ = -20.451 (aspherical surface) d ₄ = 0.499 r ₅ = INF d ₅ = D1 r ₆ = -48.096 (aspherical surface) d ₆ = 5.501 n ₃ = 1.58423 ν ₃ = 30.49 r ₇ = -15.456 (aspheric surface) d ₇ = 2.164 r ₈ = -15.093 d ₈ = 0.820 n ₄ = 1.77250 ν ₄ = 49.60 r ₉ = 110.201 (aspheric surface) d ₉ = D2 r ₁₀ = -23.399 d ₁₀ = 1.000 n ₅ = 1.72916 ν ₅ = 54.68 r ₁₁ = -94.479 Aperture surface 5 Aspherical surface first surface k = 0.0000 A ₄ = -6.4726e-005 A ₆ = -1.0710e-007 A ₈ = 8.1624e-010 A ₁₀ = 1.7228e-013 A ₁₂ = 0.0000 Surface 3 k = 0.0000 A ₄ = 1.1803e-004 A ₆ = 2.3861e-007 A ₈ = -6.7360e-010 A ₁₀ = 2.6468e-011 A ₁₂ = 0.0000 4th Surface k = 0.0000 A ₄ = 1.1663e-004 A ₆ = 5.6512e-007 A ₈ = 1.6480e-008 A ₁₀ = -1.0479e-010 A ₁₂ = 0.0000 Surface 6 k = 0.0000 A ₄ = 7.9235e-005 A ₆ = 3.6165e-007 A ₈ = 3.1862e-008 A ₁₀ = -2.6881e-010 A ₁₂ = -1.0579e-012 Surface 7 k = 0.0000 A ₄ = 2.6119e-004 A ₆ = -1.3815e-006 A ₈ = 4.5428e-008 A ₁₀ = -5.4867e-011 A ₁₂ = -2.0268e-012 Surface 9 k = 0.0000 A ₄ = -2.0086e-004 A ₆ = 2.4126e-006 A ₈ = -3.5520e-008 A ₁₀ = 2.5944e-010 A ₁₂ = -8.0358e-013 Zoom data Wide-angle end Middle Telephoto end f (mm) 39.002 83.899 180.685 F _NO 5.665 10.890 14.414 2ω (°) 54.6 27.8 13.5 FB (mm) 6.756 18.940 80.585 D1 13.240 1.824 0.600 D2 1.742 24.703 16.181 Next, Tables 1 and 2 show the values of the conditions in the above Examples.

[0108]

[Table 1]

[0109]

[Table 2] The zoom lens according to the present invention can be configured as follows.

[1] In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a brightness stop, and a second lens unit having a negative refractive power. The first lens unit having the positive refractive power includes a negative lens and a positive lens. Wherein the second group of negative refracting power comprises a positive lens and a negative lens,
A zoom lens characterized by satisfying the condition (1).

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end and fw is the focal length at the wide-angle end. [2] In order from the object side, the first lens unit includes a first group having a positive refractive power, a brightness stop, and a second group having a negative refractive power.
The first unit includes a negative lens and a positive lens, and the second unit having the negative refractive power includes two lenses having a positive combined refractive power and a negative lens, and satisfies the condition (1). Zoom lens.

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. [3] In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a negative refractive power.
A zoom lens characterized by satisfying

(2) 2.5 <ft / fw <5.5 where ft is the focal length at the telephoto end and fw is the focal length at the wide-angle end. [4] In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a negative refractive power. The first group of refractive power is composed of a negative lens and a positive lens, the second group of negative refractive power is composed of a positive lens and a negative lens, and the third group of negative refractive power is composed of one negative lens. Zoom lens characterized by that.

[5] In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a brightness stop, and a second lens unit having a negative refractive power. The first lens unit having the positive refractive power includes a negative lens and a positive lens. Wherein the second group of negative refracting power comprises a positive lens and a negative lens,
A zoom lens, wherein the second lens unit having the negative refractive power is moved to an image plane side to perform focusing on a close object.

[6] In order from the object side, the first lens unit includes a first lens unit having a positive refractive power, a brightness stop, and a second lens unit having a negative refractive power. The first lens unit having the positive refractive power includes a negative lens and a positive lens. Wherein the second group of negative refracting power comprises a positive lens and a negative lens,
A zoom lens, wherein the first group of positive lenses having a positive refractive power has an aspherical shape on both surfaces.

[7] The zoom lens of [1] to [6], wherein the following condition (3) is satisfied. (3) 0.5 <Lt / ft <1.0 where Lt is the total lens length on the telephoto side, and ft is the focal length on the telephoto side.

[8] The zoom lens of any one of [1] to [7], wherein at least one aspherical surface is used in the first lens unit. [9] The zoom lens of [8], wherein the first group of positive lenses has an aspheric surface on both sides. [10] The zoom lens of [3] to [6], wherein the following condition (1) is satisfied.

(1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. [11] The zoom lens of [4] to [6], wherein the following condition (4) is satisfied.

(4) 0.08 <f1 / ft <0.35 Here, f1 is the focal length of the first lens unit, and ft is the focal length at the telephoto end. [12] The zoom lens of [1], [2], [5], or [6], which satisfies the following condition (5).

(5) -0.3 <f22 / ft <-0.
05 Here, f22 is the focal length of the second group of the two-unit zoom lens, and ft is the focal length at the telephoto end.

[0121]

As is apparent from the above description, according to the present invention, a two-unit zoom system is constituted by a first unit having a positive refractive power and a second unit having a negative refractive power in order from the object side and sequentially from the object side. A three-unit zoom lens composed of a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a negative refractive power in order from the lens or the object side, and has a high zoom ratio with a small number of lenses. A zoom lens can be provided.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a zoom lens according to the present invention, showing a state of a zoom lens and a lens frame at a telephoto end.

FIG. 2 is a lens cross-sectional view of Example 1 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 3 is a lens cross-sectional view of Example 2 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 4 is a lens cross-sectional view of Example 3 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 5 is a lens cross-sectional view of Example 4 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 6 is a lens cross-sectional view of Example 5 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 7 is a lens cross-sectional view of Example 6 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 8 is a sectional view of a lens according to a seventh embodiment of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 9 is a lens cross-sectional view of Example 8 of the present invention, showing (a) a wide-angle end, (b) an intermediate position, and (c) a telephoto position.

FIG. 10 is a view illustrating a ninth embodiment of the present invention, in which (a) a wide-angle end and (b)
FIG. 5 is a lens cross-sectional view at an intermediate position and (c) a telephoto position.

FIG. 11 is a view illustrating a tenth embodiment of the present invention, in which (a) a wide-angle end;
FIG. 3B is a lens cross-sectional view at an intermediate position and at a telephoto position.

FIG. 12 shows Embodiment 11 of the present invention, in which (a) a wide-angle end;
FIG. 3B is a lens cross-sectional view at an intermediate position and at a telephoto position.

FIG. 13 is a view illustrating a twelfth embodiment of the present invention, in which (a) a wide-angle end;
FIG. 3B is a lens cross-sectional view at an intermediate position and at a telephoto position.

FIG. 14 is a first embodiment of the present invention, wherein (a) a wide-angle end, and (b)
It is an aberration figure in an intermediate position and (c) a telephoto position.

FIG. 15 is a second embodiment of the present invention, wherein (a) a wide-angle end, and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 16 is a diagram illustrating a third embodiment of the present invention, in which (a) a wide-angle end and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 17 is a fourth embodiment of the present invention, wherein (a) a wide-angle end, and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 18 is a view showing a fifth embodiment of the present invention, in which (a) a wide-angle end, and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 19 is a view illustrating a sixth embodiment of the present invention, in which (a) a wide-angle end and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 20 shows a seventh embodiment of the present invention, wherein (a) a wide-angle end, and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 21 shows Example 8 of the present invention, in which (a) a wide-angle end, and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 22 is a view illustrating a ninth embodiment of the present invention, in which (a) a wide-angle end and (b)
It is an aberration figure of an intermediate position and (c) a telephoto position.

FIG. 23 is a view illustrating a tenth embodiment of the present invention, in which (a) a wide-angle end;
It is an aberration figure of (b) an intermediate position and (c) a telephoto position.

FIG. 24 shows Embodiment 11 of the present invention, in which (a) a wide-angle end;
It is an aberration figure of (b) an intermediate position and (c) a telephoto position.

FIG. 25 is a view illustrating a twelfth embodiment of the present invention, in which (a) a wide-angle end;
It is an aberration figure of (b) an intermediate position and (c) a telephoto position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Zoom lens 2 Lens frame 3 Off-axis principal ray 4 Optical axis IH Image height Lt Overall length of lens at telephoto end

Claims (4)

[Claims] 1. A first group having a positive refractive power, in order from the object side,
The aperture stop comprises a second group having a negative refractive power, the first group having a positive refractive power comprises a negative lens and a positive lens, and the second group having a negative refractive power comprises a positive lens and a negative lens. And a zoom lens characterized by satisfying the condition (1). (1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. 2. A first group having a positive refractive power, in order from the object side,
The aperture stop and the second group having a negative refractive power are formed. The first group having the positive refractive power is formed with a negative lens and a positive lens. The second group having the negative refractive power has a positive combined refractive power. A zoom lens comprising two lenses and a negative lens, and satisfying a condition (1). (1) 3 <ft / fw <5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. 3. A first group of positive refractive power, in order from the object side,
A zoom lens comprising a second group having a negative refractive power and a third group having a negative refractive power, wherein the zoom lens satisfies the condition (2). (2) 2.5 <ft / fw <5.5 where ft is the focal length at the telephoto end, and fw is the focal length at the wide-angle end. 4. A first group having a positive refractive power, in order from the object side,
A second group having a negative refractive power and a third group having a negative refractive power, each of which is movable at the time of zooming; the first group having a positive refractive power includes a negative lens and a positive lens; Second with negative refractive power
A zoom lens, wherein the group includes a positive lens and a negative lens, and the third group having the negative refractive power includes a single negative lens.