# Patent

## Title
Zoom lens and image pickup apparatus including the same

## Abstract

A zoom lens, including, in order from an object side: a negative first unit being not moved for zooming; a second unit including at least one sub-unit that is moved during zooming, and having a positive refractive power as a whole; a negative third unit including an aperture stop, being not moved for zooming; a fourth unit including at least one sub-unit and being moved during zooming; and a fifth unit being not moved for zooming, at least three sub-units among the sub-units included in the second and fourth units being moved during zooming, in which focal lengths of the first and third units, and a movement amount of a sub-unit that is moved most in the second unit and a movement amount of a sub-unit that is moved most in the fourth unit during zooming from a wide angle end to a telephoto end satisfy predetermined conditions.

## Background
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a zoom lens and an image pickup apparatus including the zoom lens, and more particularly, to a zoom lens suited for use in a broadcasting television camera, a cinema camera, a video camera, a digital still camera, and a silver-halide film camera.
Description of the Related Art
In recent years, a zoom lens having a small size, a light weight, a wide angle of view, a high magnification ratio, and high optical performance is desired for use in an image pickup apparatus, e.g., a television camera, a cinema camera, a photographic camera, or a video camera. In particular, an image pickup device, e.g., a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), which is used in a television or cinema camera serving as a professional moving image pickup system, has a substantially uniform resolution over the entire image pickup range. Therefore, a zoom lens using the image pickup device is required to have a substantially uniform resolution from the center to the periphery of the screen. There are also needs for reductions in size and weight for an image pickup mode that places emphasis on mobility and operability.
Meanwhile, when a wide angle lens having a short focal length at a wide angle end is used, a wide range may be photographed, and perspective may be enhanced. Among users who want to utilize the photographing effect, there is an increased demand for a wide angle zoom lens having a wider angle, a high magnification ratio, a small size, a light weight, and high performance.
As a wide angle zoom lens, there is known a negative lead type zoom lens including a total of four or more lens units, of which a lens unit having a negative refractive power is arranged closest to an object side.
For example, in Japanese Patent Application Laid-Open No. 2014-38153, there is disclosed a six-unit zoom lens having an F-number of from about 2.2 to about 2.5 at a wide angle end, an angle of view of from about 45 degrees to about 65 degrees at the wide angle end, and a magnification ratio of from about 1.4× to about 1.7×. Moreover, in Japanese Patent No. 4957124, there is disclosed a six-unit zoom lens having an F-number of from about 1.8 to about 2.5 at a wide angle end, an angle of view of from about 35 degrees to about 60 degrees at the wide angle end, and a magnification ratio of from about 1.2× to about 1.5×. Each zoom lens includes, in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, a fifth lens unit having a positive refractive power, and a sixth lens unit having a positive refractive power.
However, in the zoom lens disclosed in each of Japanese Patent Application Laid-Open No. 2014-38153 and Japanese Patent No. 4957124, the refractive power and the lens configuration of each lens unit are disadvantageous for achieving a wider angle and a higher magnification, with the result that it becomes difficult to suppress an increase in lens diameter accompanying the achievement of the wide angle and an increase in total length accompanying the achievement of the high magnification. In particular, when the angle of view exceeds 70 degrees at the wide angle end, a tendency toward the increased lens diameter becomes significant, and when the magnification ratio exceeds 2×, a tendency toward an increase in movement amount of a magnification varying lens unit becomes significant.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide, by appropriately setting refractive powers, lens configurations, aberration shares, and other such conditions of respective lens units, a zoom lens having a wide angle of view, a high magnification ratio, a small size, a light weight, and high optical performance over the entire zoom range. Specifically, it is an object of the present invention to provide a small, lightweight, and high-performance zoom lens having an angle of view of from about 70 degrees to about 120 degrees at a wide angle end, and a magnification ratio of from about 2 to about 5.
In order to attain the object described above, according to one embodiment of the present invention, there are provided a zoom lens and an image pickup apparatus including the zoom lens, including in order from an object side to an image side: a first lens unit having a negative refractive power and being not moved for zooming; a second lens unit including at least one lens sub unit that is moved during zooming as a whole, and having a positive refractive power; a third lens unit including an aperture stop, being not moved for zooming, and having a negative refractive power; a fourth lens unit including at least one lens sub unit, and being moved during zooming; and a fifth lens unit being not moved for zooming, among the lens sub units included in the second lens unit and the lens sub units included in the fourth lens unit, at least three of the lens sub units being moved in an optical axis direction during zooming, in which the following expressions are satisfied:

0.6<f1/f3<4.0; and

1.4<|m2|/|m4|<50.0,

where f1 and f3 respectively represent focal lengths of the first lens unit and the third lens unit, and m2 and m4 respectively represent a movement amount of a lens sub unit that is moved by a largest amount in the second lens unit and a movement amount of a lens sub unit that is moved by a largest amount in the fourth lens unit during zooming from a wide angle end to a telephoto end.

Through appropriate setting of the refractive powers, the lens configurations, the aberration shares, and other such conditions of the respective lens units, there can be obtained the zoom lens having the wide angle of view, the high magnification ratio, the small size, the light weight, and the high optical performance over the entire zoom range.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a lens cross-sectional view in a state in which focus is at infinity at a wide angle end according to Embodiment 1 (Numerical Embodiment 1) of the present invention.
FIG. 2A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 1.
FIG. 2B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 1.
FIG. 2C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 1.
FIG. 3 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 2 (Numerical Embodiment 2) of the present invention.
FIG. 4A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 2.
FIG. 4B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 2.
FIG. 4C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 2.
FIG. 5 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 3 (Numerical Embodiment 3) of the present invention.
FIG. 6A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 3.
FIG. 6B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 3.
FIG. 6C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 3.
FIG. 7 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 4 (Numerical Embodiment 4) of the present invention.
FIG. 8A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 4.
FIG. 8B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 4.
FIG. 8C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 4.
FIG. 9 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 5 (Numerical Embodiment 5) of the present invention.
FIG. 10A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 5.
FIG. 10B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 5.
FIG. 10C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 5.
FIG. 11 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 6 (Numerical Embodiment 6) of the present invention.
FIG. 12A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 6.
FIG. 12B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 6.
FIG. 12C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 6.
FIG. 13 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 7 (Numerical Embodiment 7) of the present invention.
FIG. 14A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 7.
FIG. 14B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 7.
FIG. 14C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 7.
FIG. 15 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 8 (Numerical Embodiment 8) of the present invention.
FIG. 16A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 8.
FIG. 16B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 8.
FIG. 16C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 8.
FIG. 17 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 9 (Numerical Embodiment 9) of the present invention.
FIG. 18A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 9.
FIG. 18B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 9.
FIG. 18C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 9.
FIG. 19 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 10 (Numerical Embodiment 10) of the present invention.
FIG. 20A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 10.
FIG. 20B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 10.
FIG. 20C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 10.
FIG. 21 is a lens cross-sectional view in the state in which focus is at infinity at a wide angle end according to Embodiment 11 (Numerical Embodiment 11) of the present invention.
FIG. 22A is an aberration diagram in the state in which focus is at infinity at the wide angle end according to Numerical Embodiment 11.
FIG. 22B is an aberration diagram in the state in which focus is at infinity at an intermediate zoom position according to Numerical Embodiment 11.
FIG. 22C is an aberration diagram in the state in which focus is at infinity at a telephoto end according to Numerical Embodiment 11.
FIG. 23A is an optical path diagram of Numerical Embodiment 1 at the wide angle end.
FIG. 23B is an optical path diagram of Numerical Embodiment 1 at the telephoto end.
FIG. 24 is a schematic diagram regarding chromatic aberration correction for two colors of an axial chromatic aberration by a positive lens unit, and a residual secondary spectrum.
FIG. 25 is a schematic diagram for illustrating a main part of an image pickup apparatus according to the present invention.



DESCRIPTION OF THE EMBODIMENTS
Now, exemplary embodiments of the present invention are described in detail with reference to the attached drawings. First, features of a zoom lens according to the present invention are described along with conditional expressions.
In order to achieve a wide angle of view, a high magnification ratio, a small size, a light weight, and high optical performance over the entire zoom range, the present invention has a feature of defining a ratio of focal lengths of a first lens unit and a third lens unit, which is configured not to move for zooming, and a ratio of movement amounts of sub units that are configured to move by the largest amount respectively in a second lens unit and a fourth lens unit.
Specifically, the zoom lens according to the present invention includes, in order from an object side: a first lens unit having a negative refractive power, and being configured not to move for zooming; a second lens unit including at least one lens sub unit that is configured to move during zooming, and having a positive refractive power as a whole; a third lens unit including an aperture stop, being configured not to move for zooming, and having a negative refractive power; a fourth lens unit including at least one sub lens unit, and being configured to move during zooming; and a fifth lens unit configured not to move for zooming. Moreover, at least three lens units are configured to move in an optical axis direction during zooming. In other word, among the lens sub units included in the second lens unit and the lens sub units included in the fourth lens unit, at least three of the lens sub units are moved in an optical axis direction during zooming. When focal lengths of the above-mentioned first lens unit and the above-mentioned third lens unit are respectively represented by f1 and f3, and when a movement amount of a lens sub unit that is configured to move by the largest amount in the above-mentioned second lens unit and a movement amount of a lens sub unit that is configured to move by the largest amount in the above-mentioned fourth lens unit during zooming from a wide angle end to a telephoto end are respectively represented by m2 and m4, the zoom lens has a feature that the following conditions are satisfied:

0.6<f1/f3<4.0  (1); and

1.4<|m2|/|m4|<50.0  (2).

Described below are optical actions obtained by configuring, in the present invention, the zoom lens to include the first lens unit having the negative refractive power, and being configured not to move for zooming, the second lens unit having the positive refractive power, and being configured to move during zooming, and the third lens unit having the negative refractive power.
FIG. 23A and FIG. 23B are respectively optical path diagrams of Embodiment 1 of the present invention at the wide angle end and the telephoto end. A first lens unit L1, a second lens unit L2, a third lens unit L3, a fourth lens unit L4, and a fifth lens unit L5 are illustrated. The second lens unit L2 is divided into two lens sub units: a lens sub unit L21 and a lens sub unit L22. The fourth lens unit includes one lens sub unit: a lens sub unit L41. As can be seen from FIG. 23A and FIG. 23B, in each of Embodiments of the present invention, the first lens unit and the second lens unit are configured to move along loci in which the first lens unit and the second lens unit are away from each other at the wide angle end, and in which the second lens unit is brought closer to the first lens unit at the telephoto end. With the first lens unit, which has the negative refractive power, and the second lens unit, which has the positive refractive power, being arranged away from each other at the wide angle end, an absolute value of a lateral magnification of the second lens unit may be reduced at the wide angle end, and an entrance pupil may be pushed to the object side. Therefore, the structure is advantageous in achieving both the wide angle and reductions in size and weight. Described next are optical actions obtained by configuring the zoom lens to include the third lens unit having the negative refractive power, and being configured not to move for zooming, and the lens sub unit L41, which is configured to move during zooming. Light that has exited the second lens unit enters the third lens unit as convergent light, and a ray that has entered the third lens unit enters the lens sub unit L41 as divergent light. Therefore, an image point of the third lens unit, that is, an object point of the lens sub unit L41 exists on the object side of the lens sub unit L41. The lens sub unit L41 is a lens unit configured to correct a movement of an image plane, which is caused by zooming, and is configured to move for image plane correction from the wide angle end to the telephoto end. Therefore, with the fourth lens unit being configured to correct the movement of the image plane, which is caused by zooming, a magnification increasing action is generated, and hence the high magnification ratio may be achieved effectively. Moreover, with the aperture stop being arranged in the third lens unit, which is configured not to move for zooming, the mechanism of the aperture stop is configured not to move for zooming, and reductions in weight of movable lens units may be achieved. Further, with the three or more lens units being configured to move during zooming, variations in spherical aberration and field curvature are corrected.
Further, the expressions (1) and (2) described above may be satisfied to effectively achieve the wide angle of view, the small size, the light weight, and the high optical performance over the entire zoom range.
The expression (1) defines a relationship between the first lens unit and the third lens unit, which are configured not to move for zooming. The expression (1) is satisfied to effectively achieve the high magnification ratio, the small size, the light weight, and the high optical performance. When the upper limit of the expression (1) is not satisfied, the refractive power of the third lens unit becomes stronger. Therefore, a height of a beam that enters the fourth lens unit becomes higher, and aberration variations accompanying zooming, in particular, a variation in spherical aberration becomes larger, with the result that it becomes difficult to achieve good optical performance over the entire zoom range. When the lower limit of the expression (1) is not satisfied, the refractive power of the third lens unit becomes weaker, and hence the image point of the third lens unit (that is, the object point of the fourth lens unit) moves relatively away toward the object side. Therefore, a movement amount of a lens unit that is configured to perform the image plane correction of the fourth lens unit accompanying zooming becomes larger, and it becomes difficult to reduce the size and weight. It is more preferred to set the expression (1) as follows:

0.65<f1/f3<3.65  (1a).

Moreover, the expression (2) defines a ratio between a movement amount of a lens sub unit that is configured to move by the largest amount in the second lens unit and a movement amount of a lens sub unit that is configured to move by the largest amount in the fourth lens unit during zooming from the wide angle end to the telephoto end. The expression (2) is satisfied to effectively achieve the high magnification ratio, the small size, the light weight, and the high optical performance. When the upper limit of the expression (2) is not satisfied, the movement amount of the second lens unit becomes much larger, and a distance between the first lens unit and the aperture stop becomes larger. Therefore, the first lens unit is disadvantageously increased in size, and it becomes difficult to achieve both the high magnification ratio and the reductions in size and weight. When the lower limit of the expression (2) is not satisfied, the movement amount of the fourth lens unit becomes much larger, and a distance between the fifth lens unit and the aperture stop becomes larger. Therefore, the fifth lens unit is disadvantageously increased in size, and it becomes difficult to achieve both the high magnification ratio and the reductions in size and weight.
It is more preferred to set the expression (2) as follows:

1.55<|m2|/|m4|<20.00  (2a).

As a further aspect of the zoom lens according to the present invention, a magnification share of the second lens unit, which is a main magnification varying lens unit, is defined. It is preferred that a lateral magnification β2_w of the second lens unit at the wide angle end when focused at infinity, and a lateral magnification β2_t of the second lens unit at the telephoto end when focused at infinity satisfy the following conditional expression:

1.5<β2_t/β2_w<4.0  (3).

The expression (3) is satisfied so that the second lens unit, which is the main magnification varying lens unit, is configured to make a predetermined contribution or more to magnification varying, resulting in the structure that is advantageous in achieving the wide angle and the high magnification ratio. When the upper limit of the expression (3) is not satisfied, the movement amount of the second lens unit for the zooming becomes much larger, and the distance from the stop becomes much farther toward the object side at the telephoto end. As a result, a beam height of the axial ray that passes through the second lens unit is significantly changed by zooming from the wide angle end to the telephoto end, and hence it becomes difficult to suppress variations in spherical aberration and coma caused by zooming. When the lower limit of the expression (3) is not satisfied, it becomes difficult to achieve the high magnification ratio, and an interval between the first lens unit and the second lens unit becomes shorter at the wide angle end. As a result, it becomes difficult to reduce the lateral magnification of the second lens unit, and hence it becomes difficult to achieve the wide angle. It is more preferred to set the expression (3) as follows:

1.7<β2_t/β2_w<3.0  (3a).

As a further aspect of the zoom lens according to the present invention, defined is a relationship between a focal length of the first lens unit, and a focal length of the zoom lens at the wide angle end in a state of being focused at infinity. It is preferred that a focal length f1 of the first lens unit and a focal length fw of the zoom lens at the wide angle end satisfy the following conditional expression:

−5.0<f1/fw<−1.5  (4).

The expression (4) may be satisfied to achieve the high optical performance while achieving both the wide angle and the reductions in size and weight. When the upper limit of the expression (4) is not satisfied, the refractive power of the first lens unit becomes stronger, and it becomes difficult to correct the aberration variations accompanying zooming and aberration variations accompanying focusing. When the lower limit condition of the expression (4) is not satisfied, the refractive power of the first lens unit becomes insufficient, and hence it becomes difficult to achieve both the wide angle and the reductions in size and weight. It is more preferred to set the expression (4) as follows:

−4.0<f1/fw<−1.7  (4a).

It is further preferred to set the expression (4) as follows:

−2.5<f1/fw<−1.7  (4b).

As a further aspect of the zoom lens according to the present invention, the absolute value of the lateral magnification of the second lens unit at the wide angle end is defined. It is preferred that an absolute value |β2_w| of the lateral magnification of the second lens unit at the wide angle end when focused at infinity satisfy the following conditional expression:

|β2_w|<1.0  (5).

The expression (5) may be satisfied to achieve the wide angle. When the expression (5) is not satisfied, the lateral magnification of the second lens unit becomes much larger at the wide angle end, and the wide angle is not achieved. It is more preferred to set the expression (5) as follows:

|β2_w|<0.75  (5a).

As a further aspect of the zoom lens according to the present invention, it is defined that the third lens unit includes at least two lenses having negative refractive powers. Including the two or more lenses having negative refractive powers may achieve the high optical performance. When the third lens unit is formed of one lens having a negative refractive power, the refractive power of the lens having the negative refractive power becomes much higher, and a large high-order spherical aberration and other such aberrations are generated, with the result that it becomes difficult to correct the aberrations.
As a further aspect of the zoom lens according to the present invention, it is defined that a lens closest to the object side in the first lens unit has a negative refractive power. With the lens closest to the object side in the first lens unit having the negative refractive power, both the wide angle and the reductions in size and weight may be achieved. When the lens closest to the object side in the first lens unit has a positive refractive power, a lens having a large diameter and a high negative refractive power needs to be arranged as a lens on the image side of the lens closest to the object side, and it becomes difficult to achieve both the wide angle and the reductions in size and weight.
As a further aspect of the zoom lens according to the present invention, it is defined that the first lens unit has the structure including a lens sub unit L11 having a negative refractive power, and being configured not to move for focusing, and a lens sub unit L12, which is configured to move during focusing. With the structure in which focusing is performed in the first lens unit, an movement amount for focusing may be made constant irrespective of zooming, resulting in a simplified drive mechanism and the structure that is advantageous in reducing the size of the focus lens unit.
As a further aspect of the zoom lens according to the present invention, a relationship between the lens sub unit L11 and the lens sub unit L12 in the first lens unit is defined. The above-mentioned lens sub unit L12, which is configured to move during focusing, is configured to have a positive refractive power, and it is preferred that a focal length f11 of the lens sub unit L11 and a focal length f12p of the lens sub unit L12 satisfy the following conditional expression:

−0.15<f11/f12p<−0.04  (6).

When the upper limit of the expression (6) is not satisfied, the positive refractive power of the lens sub unit L12 becomes weaker, and hence a movement amount for focusing becomes larger, with the result that it becomes difficult to reduce the size and weight. When the lower limit of the expression (6) is not satisfied, the positive refractive power of the lens sub unit L12 becomes stronger, and hence the negative refractive power of the first lens unit as a whole cannot be increased, with the result that it becomes difficult to achieve the wide angle and the reduction in size. It is more preferred to set the expression (6) as follows:

−0.12<f11/f12p<−0.05  (6a).

As a further aspect of the zoom lens according to the present invention, a relationship between the lens sub unit L11 and the lens sub unit L12 in the first lens unit is defined. The above-mentioned lens sub unit L12, which is configured to move during focusing, is configured to have a negative refractive power, and it is preferred that the focal length f11 of the lens sub unit L11 and a focal length f12n of the lens sub unit L12 satisfy the following conditional expression:

0.3<f11/f12n<0.8  (7).

When the upper limit of the expression (7) is not satisfied, the negative refractive power of the lens sub unit L12 becomes much stronger, and it becomes difficult to correct a variation in field curvature and other such variations in off-axial aberrations caused by focusing. When the lower limit of the expression (7) is not satisfied, the negative refractive power of the lens sub unit L12 becomes weaker, and hence the movement amount for focusing is increased, and it becomes difficult to reduce the size and weight. It is more preferred to set the expression (7) as follows:

0.35<f11/f12n<0.75  (7a).

As a further aspect of the zoom lens according to the present invention, it is defined that the second lens unit includes at least one cemented lens including one convex lens and one concave lens, and that one of the at least one cemented lens has a predetermined partial dispersion ratio of optical materials.
When an Abbe number and a partial dispersion ratio of the convex lens of the cemented lens including one convex lens and one concave lens are respectively represented by ν2p and θ2p, and an Abbe number and a partial dispersion ratio of the concave lens are respectively represented by ν2n and θ2n, it is preferred that the second lens unit include a cemented lens that satisfies the following conditional expression:

−3.00×10−3<(θ2p−θ2n)/(ν2p−ν2n)<−1.5×10−3  (8).

Here, an Abbe number and a partial dispersion ratio of a material of an optical element (lens) used in the present invention are described as follows. When refractive indices for a g-line (435.8 nm), an F-line (486.1 nm), a d-line (587.6 nm), and a C-line (656.3 nm) of Fraunhofer lines are respectively represented by Ng, NF, Nd, and NC, an Abbe number νd and a partial dispersion ratio θgF with respect to the g-line and the F-line are expressed as follows:

νd=(Nd−1)/(NF−NC)  (i); and

θgF=(Ng−NF)/(NF−NC)  (ii).

Existing optical materials have the partial dispersion ratio θgF in a narrow range with respect to the Abbe number νd. Moreover, the existing optical materials have tendencies that as the Abbe number νd becomes smaller, the partial dispersion ratio θgF becomes larger, and that as the Abbe number νd becomes larger, the refractive index becomes lower. Here, a condition for correcting chromatic aberrations of a thin contact optical system, which respectively includes two lenses 1 and 2 having refractive powers φ1 and φ2, and having Abbe numbers ν1 and ν2 is respectively expressed as follows:

φ1/ν1+φ2/ν2=E  (iii).

Here, a combined refractive power φ of the lenses 1 and 2 is expressed as follows:

φ=φ1+φ2  (iv).

In the expression (iii), when E=0 is satisfied, image forming positions of the C-line and the F-line match in chromatic aberrations. At this time, φ1 and φ2 are expressed by the following expressions:

φ1=φ×ν1/(ν1−ν2)  (v); and

φ2=φ×ν2/(ν1−ν2)  (vi).

FIG. 24 is a schematic diagram regarding chromatic aberration correction for two colors of an axial chromatic aberration by a lens unit LP having a positive refractive power, and a residual secondary spectrum. In FIG. 24, a material having a large Abbe number ν1 and a material having a small Abbe number ν2 are respectively used for the positive lens 1 and the negative lens 2. Therefore, the positive lens 1 has a small partial dispersion ratio θ1, and the negative lens 2 has a large partial dispersion ratio θ2. As a result, when the axial chromatic aberration is corrected for the C-line and the F-line, an image forming point of the g-line is shifted toward the image side. When a shift amount of the axial chromatic aberration of the g-line with respect to the C-line and the F-line when a light flux enters with an object distance being infinity is defined as a secondary spectrum amount ΔS, the secondary spectrum amount ΔS is expressed as follows:

ΔS=−(1/φ)×(θ1−θ2)/(ν1−ν2)  (vii).

In order to satisfactorily correct the secondary spectrum of the axial chromatic aberration at the telephoto end, there is a need to adjust a generation amount in the second lens unit, in which a significant amount of secondary spectrum is generated. The second lens unit has the positive refractive power, and in order to satisfactorily correct the secondary spectrum of the axial chromatic aberration at the telephoto end, there is a need to select such a glass material that reduces the secondary spectrum amount ΔS generated in the second lens unit.
The condition of the expression (8) is defined to achieve the correction of the axial chromatic aberration at the telephoto end and the high optical performance. When the upper limit condition of the expression (8) is not satisfied, the secondary spectrum of the axial chromatic aberration is advantageously corrected at the telephoto end. However, the refractive index of the convex lens forming the second lens unit becomes lower, and a curvature radius of the convex lens forming the second lens unit becomes smaller. As a result, higher-order aberrations of spherical aberration are increased at the telephoto end, and it becomes difficult to achieve good optical performance. To the contrary, when the lower limit condition of the expression (8) is not satisfied, the secondary spectrum of the axial chromatic aberration is increased at the telephoto end, and it becomes difficult to satisfactorily correct the chromatic aberrations at the telephoto end. It is more preferred to set the expression (8) as follows:

−2.80×10−3<(θ2p−θ2n)/(ν2p−ν2n)<−1.60×10−3  (8a).

As a further aspect of the zoom lens according to the present invention, it is defined that the second lens unit or the fourth lens unit includes a lens having at least one aspherical surface. As can be seen from FIG. 23A and FIG. 23B, a ray of a lens unit that is configured to move during zooming undergoes a change in height of an axial ray and a change in height of an off-axial ray accompanying zooming from the wide angle end to the telephoto end. Therefore, arrangement of the lens having the aspherical surface in the second lens unit or the fourth lens unit may effectively suppress variations in spherical aberration, coma, and field curvature caused by zooming.
As a further aspect of the zoom lens according to the present invention, a ratio between the focal length of the first lens unit L1 and a focal length of the lens sub unit L21 is defined. It is preferred that the focal length f1 of the first lens unit L1 and a focal length f21 of the lens sub unit L21 satisfy the following conditional expression:

−0.60<f1/f21<−0.15  (9).

The expression (9) is satisfied to achieve both the wide angle of the zoom lens and the correction of the aberration variations. A focal length of the zoom lens takes a value obtained by multiplying the focal length of the first lens unit L1 by a lateral magnification of lens units on the image side of the first lens unit L1, and hence in order to achieve the wide angle, there is a need to appropriately set the focal length of the first lens unit L1. When the upper limit condition of the expression (9) is not satisfied, the refractive power of the first lens unit L1 becomes stronger, and it becomes difficult to correct the aberration variations accompanying zooming and the aberration variations accompanying focusing. When the lower limit condition of the expression (9) is not satisfied, the refractive power of the first lens unit L1 becomes insufficient, and hence it becomes difficult to achieve both the wide angle and the reductions in size and weight. It is more preferred to set the expression (9) as follows:

−0.55<f1/f21<−0.20  (9a).

As a further aspect of the zoom lens according to the present invention, a relationship between focal lengths of the first lens unit L1 and the fourth lens unit L4 is defined. It is preferred that the focal length f1 of the first lens unit L1 and a focal length f4 of the fourth lens unit L4 satisfy the following conditional expression:

−1.00<f1/f4<−0.15  (10).

The expression (10) may be satisfied to achieve both the satisfactory correction of aberrations and the reduction in size. When the upper limit of the expression (10) is not satisfied, the refractive power of the fourth lens unit L4 becomes relatively weaker, and a movement amount for zooming becomes larger, with the result that it becomes difficult to reduce the size and weight. When the lower limit of the expression (10) is not satisfied, the refractive power of the fourth lens unit L4 becomes relatively stronger, and it becomes difficult to suppress variations in spherical aberration and coma caused by zooming. It is more preferred to set the expression (10) as follows:

−0.90<f1/f4<−0.20  (10a).

As a further aspect of the zoom lens according to the present invention, a relationship between focal lengths of the lens sub unit L21 and the lens sub unit L22 is defined. It is preferred that the focal length f21 of the lens sub unit L21 and a focal length f22 of the lens sub unit L22 satisfy the following conditional expression:

0.80<f21/f22<1.80  (11).

The expression (11) may be satisfied to satisfactorily correct variations in spherical aberration, coma, and field curvature caused by zooming. When the upper limit of the expression (11) is not satisfied, the refractive power of the lens sub unit L21 becomes relatively weaker, and a height of a beam that enters the lens sub unit L22 becomes higher, with the result that it becomes difficult to suppress the variation in spherical aberration caused by zooming. When the lower limit of the expression (11) is not satisfied, the refractive power of the lens sub unit L22 becomes relatively weaker, and the effect of correcting the variations in spherical aberration and coma by changing an interval between the lens sub unit L21 and the lens sub unit L22 is reduced, with the result that it becomes difficult to suppress the aberration variations caused by zooming. It is more preferred to set the expression (11) as follows:

0.90<f21/f22<1.65  (11a).

Further, an image pickup apparatus according to the present invention has a feature in including the zoom lens according to each of Embodiments and a solid-state image pickup element having a predetermined effective image pickup range, which is configured to receive light of an image formed by the zoom lens.
Now, a specific configuration of the zoom lens according to the present invention is described by way of features of lens configurations of Numerical Embodiments 1 to 11 corresponding to Embodiments 1 to 11, respectively.
Embodiment 1
FIG. 1 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 1 (Numerical Embodiment 1) of the present invention. FIG. 2A, FIG. 2B, and FIG. 2C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 30 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In addition, the value of the focal length is a value when corresponding value in Numerical Embodiment 1 to be described later is represented in units of mm. This also applies to Numerical Embodiments described below.
In FIG. 1, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21, which is one lens sub unit of the second lens unit L2 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22, which is another lens sub unit of the second lens unit L2 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 of the fourth lens unit L4 having a positive refractive power, and being configured to move on the optical axis in conjunction with the movement of the second lens unit to correct an image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action. An aperture stop is denoted by SP. When used as an image pickup optical system for a broadcasting television camera, a video camera, or a digital still camera, an image plane I corresponds to an image pickup surface of a solid-state image pickup element (photoelectric converter) or the like configured to receive light of an image formed by the zoom lens and to convert light to electricity. When used as an image pickup optical system for a film camera, the image plane I corresponds to a film surface on which the image formed by the zoom lens is exposed.
In each of the longitudinal aberration diagrams, spherical aberrations are respectively illustrated with respect to an e-line and the g-line by a solid line and a two-dot chain line. Further, astigmatisms are illustrated on a meridional image plane by a broken line and on a sagittal image plane by a solid line. In addition, lateral chromatic aberrations are illustrated with respect to the g-line by a two-dot chain line. A half angle of view is denoted by ω and an F-number is denoted by Fno. In each of the longitudinal aberration diagrams, a spherical aberration is illustrated in the unit of 0.4 mm, an astigmatism in the unit of 0.4 mm, a distortion in the unit of 5%, and a lateral chromatic aberration in the unit of 0.05 mm. In each Embodiment described below, each of the wide angle end and the telephoto end refers to a zooming position obtained when the lens unit for magnification varying is positioned at each of the ends of a range in which the lens unit may mechanically move along the optical axis.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit L11 having a negative refractive power, and being configured not to move for focusing, and a lens sub unit L12 having a positive refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens that is convex toward the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the seventh surface to the ninth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the tenth surface and the eleventh surface, and includes a biconvex lens. Moreover, the tenth surface and the eleventh surface have aspherical shapes to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the twelfth surface to the eighteenth surface, and includes the aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, a biconcave lens, and an auxiliary stop. The auxiliary stop as the eighteenth surface is configured to change its aperture diameter depending on zooming to keep the maximum F-number at each zoom position constant. The lens sub unit L41 corresponds to the nineteenth surface to the twenty-first surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-second surface to the twenty-ninth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens, a concave meniscus lens having a convex surface on the object side, and a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side.
Numerical Embodiment 1, which corresponds to Embodiment 1 described above, is described. In all Numerical Embodiments without limiting to Numerical Embodiment 1, the order of a surface (optical surface) from the object side is represented by i, a curvature radius of the i-th surface from the object side is represented by ri, and an interval between the i-th surface and the (i+1)th surface from the object side (on the optical axis) is represented by di. Moreover, a refractive index, an Abbe number, and a partial dispersion ratio of a medium (optical member) between the i-th surface and the (i+1)th surface are respectively represented by ndi, νdi, and θgFi, and an air-equivalent back focus is represented by BF. When an X axis is set in the optical axis direction, an H axis is set in a direction perpendicular to the optical axis, a direction of travel of light is defined as positive, a paraxial curvature radius is represented by R, a conic constant is represented by k, and aspherical coefficients are represented by A4, A6, A8, A10, and A12, the aspherical shape is expressed by the expression below. Moreover, “e-Z” means “×10−z”.




  X
  =
  
    
      
        
          H
          2
        
        /
        R
      
      
        1
        +
        
          
            1
            -
            
              
                (
                
                  1
                  +
                  k
                
                )
              
              ⁢
              
                
                  (
                  
                    H
                    /
                    R
                  
                  )
                
                2
              
            
          
        
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      4
      ⁢
      
        H
        4
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      6
      ⁢
      
        H
        6
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      8
      ⁢
      
        H
        8
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      10
      ⁢
      
        H
        10
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      12
      ⁢
      
        H
        12
      
    
  




Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expressions (7) to (11) to achieve a photographing angle of view (angle of view) of 77.4 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized. It is essential that the zoom lens according to the present invention satisfy the expressions (1) and (2), but the zoom lens does not always need to satisfy the expressions (3) to (11). However, when at least one of the expressions (3) to (11) is satisfied, even better effects may be provided. This is also true for the other Embodiments.
FIG. 25 is a schematic diagram of an image pickup apparatus (television camera system) using the zoom lens according to each of Embodiments as a photographing optical system. In FIG. 25, the zoom lens according to any one of Embodiments 1 to 11, which is denoted by 101, and a camera 124 are illustrated. The zoom lens 101 is configured to be detachably attachable to the camera 124. An image pickup apparatus 125 is formed by attaching the zoom lens 101 to the camera 124. The zoom lens 101 includes a first lens unit F, a magnification varying portion LZ, and a fifth lens unit R for image formation. The first lens unit F includes a lens unit for focusing. The magnification varying portion LZ includes a second lens unit, which is configured to move on the optical axis for zooming, a third lens unit, which is configured not to move for zooming, and a fourth lens unit, which is configured to move on the optical axis for zooming. An aperture stop is denoted by SP. Drive mechanisms 114 and 115, such as helicoids or cams, are respectively configured to drive the first lens unit F and the magnification varying portion LZ in the optical axis direction. Motors (drive units) 116 to 118 are respectively configured to electrically drive the drive mechanisms 114 and 115 and the aperture stop SP. Detectors 119 to 121, such as encoders, potentiometers, or photosensors, are respectively configured to detect positions of the first lens unit F and the magnification varying portion LZ on the optical axis, and an aperture diameter of the aperture stop SP. In the camera 124, a glass block 109 corresponds to an optical filter or a color separation optical system in the camera 124, and a solid-state image pickup element (photoelectric converter) 110, such as a charge-coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor, is configured to receive light of a subject image formed by the zoom lens 101. Moreover, central processing units (CPUs) 111 and 122 are respectively configured to control various kinds of driving of the camera 124 and the zoom lens 101.
As described above, the zoom lens according to the present invention is applied to a television camera or a cinema camera to realize an image pickup apparatus having high optical performance.
Embodiment 2
FIG. 3 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 2 (Numerical Embodiment 2) of the present invention. FIG. 4A, FIG. 4B, and FIG. 4C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 27 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 3, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 having a positive refractive power, and being configured to move nonlinearly on the optical axis in conjunction with the movements of the second lens unit and the third lens unit to correct an image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the fifth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a negative refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens that is convex toward the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the sixth surface to the eighth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the ninth surface and the tenth surface, and includes a biconvex lens. Moreover, the ninth surface and the tenth surface have aspherical shapes to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the eleventh surface to the seventeenth surface, and includes the aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, a biconcave lens, and an auxiliary stop. The lens sub unit L41 corresponds to the eighteenth surface to the twelfth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-first surface to the twenty-eighth surface, and includes a biconvex lens, a cemented lens formed of a biconvex lens and a biconcave lens, and a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expressions (7) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 87.4 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 3
FIG. 5 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 3 (Numerical Embodiment 3) of the present invention. FIG. 6A, FIG. 6B, and FIG. 6C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 36 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 5, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. In this Embodiment, the second lens unit is formed of the lens sub unit L21. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L42 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a negative refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The lens sub unit L21 corresponds to the seventh surface to the eleventh surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side, and a biconvex lens. The third lens unit L3 corresponds to the twelfth surface to the seventeenth surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, and a biconcave lens. The lens sub unit L41 corresponds to the eighteenth surface and the nineteenth surface, and includes a biconvex lens. Moreover, the eighteenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The lens sub unit L42 corresponds to the twentieth surface to the twenty-second surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The fifth lens unit L5 corresponds to the twenty-third surface to the twenty-fifth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expressions (7) and (8) to achieve a wide angle of view with a photographing angle of view (angle of view) of 78.8 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 4
FIG. 7 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 4 (Numerical Embodiment 4) of the present invention. FIG. 8A, FIG. 8B, and FIG. 8C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 35 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 7, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 having a positive refractive power, and being configured to move nonlinearly on the optical axis in conjunction with the movement of the second lens unit and the third lens unit to correct an image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a negative refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the seventh surface to the ninth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the tenth surface and the eleventh surface, and includes a biconvex lens. Moreover, the tenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the twelfth surface to the seventeenth surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, and a biconcave lens. The lens sub unit L41 corresponds to the eighteenth surface and the nineteenth surface, and includes a biconvex lens. Moreover, the eighteenth surface has an aspherical shape to mainly correct a variation in spherical aberration accompanying zooming. The fifth lens unit L5 corresponds to the twentieth surface to the twenty-fifth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side, and a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expressions (7) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 83.8 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 5
FIG. 9 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 5 (Numerical Embodiment 5) of the present invention. FIG. 10A, FIG. 10B, and FIG. 10C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 25 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 9, the zoom lens includes, in order from the object side to the image side: a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 having a positive refractive power, and being configured to move nonlinearly on the optical axis in conjunction with the movements of the second lens unit and the third lens unit to correct an image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the tenth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a positive refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side, a biconcave lens, and a convex meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconvex lens and a biconcave lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the eleventh surface to the thirteenth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the fourteenth surface and the fifteenth surface, and includes a biconvex lens. Moreover, the fourteenth surface and the fifteenth surface have aspherical shapes to mainly correct variations in spherical aberration, coma, and field curvature accompanying zooming. The third lens unit L3 corresponds to the sixteenth surface to the twenty-first surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side. The lens sub unit L41 corresponds to the twenty-second surface to the twenty-fourth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-fifth surface to the thirty-first surface, and includes a biconvex lens, a concave meniscus lens having a convex surface on the object side, and a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (6) and the expressions (8) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 97.4 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 6
FIG. 11 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 6 (Numerical Embodiment 6) of the present invention. FIG. 12A, FIG. 12B, and FIG. 12C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 35 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 11, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a negative refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 having a positive refractive power, and being configured to move nonlinearly on the optical axis in conjunction with the movements of the second lens unit and the third lens unit to correct the image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface and the second surface. The first lens unit L1 includes a first lens unit having a negative refractive power, and being configured not to move for focusing. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the third surface to the sixth surface, and includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The entire lens sub unit is configured to move toward the object side during focusing from the infinity side to the proximity side. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the seventh surface to the eleventh surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side, and a biconvex lens. Moreover, the tenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the twelfth surface to the seventeenth surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, and a concave meniscus lens having a convex surface on the image side. The lens sub unit L41 corresponds to the eighteenth surface and the nineteenth surface, and includes a biconvex lens. Moreover, the eighteenth surface has an aspherical shape to mainly correct a variation in spherical aberration accompanying zooming. The fifth lens unit L5 corresponds to the twentieth surface to the twenty-fourth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side, and a biconvex lens.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expression (8) to achieve a wide angle of view with a photographing angle of view (angle of view) of 82.0 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 7
FIG. 13 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 7 (Numerical Embodiment 7) of the present invention. FIG. 14A, FIG. 14B, and FIG. 14C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 27 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 13, the zoom lens includes, in order from the object side to the image side: a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L42 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit L11 having a negative refractive power, and being configured not to move for focusing, and a lens sub unit L12 having a negative refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the seventh surface to the ninth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the tenth surface and the eleventh surface, and includes a biconvex lens. Moreover, the tenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the twelfth surface to the seventeenth surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, and a biconcave lens. The lens sub unit L41 corresponds to the eighteenth surface and the nineteenth surface, and includes a biconvex lens. Moreover, the eighteenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The lens sub unit L42 corresponds to the twentieth surface to the twenty-second surface, and includes a cemented lens formed of a convex meniscus lens having a convex surface on the image side and a concave meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-third surface to the twenty-fifth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5) and the expressions (7) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 87.4 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 8
FIG. 15 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 8 (Numerical Embodiment 8) of the present invention. FIG. 16A, FIG. 16B, and FIG. 16C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 30 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 15, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L42 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a negative refractive power. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured to not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the twelfth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a positive refractive power, and being configured to move toward the image side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side, a concave meniscus lens having a convex surface on the object side, a biconcave lens, and a convex meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a convex meniscus lens having a convex surface on the image side, and a biconcave lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the thirteenth surface to the fifteenth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the sixteenth surface and the seventeenth surface, and includes a biconvex lens. Moreover, the sixteenth surface and the seventeenth surface have aspherical shapes to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the eighteenth surface to the twenty-third surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a biconvex lens, and a biconcave lens. The lens sub unit L41 corresponds to the twenty-fourth surface to the twenty-seventh surface, and includes a convex meniscus lens having a convex surface on the image side, and a biconvex lens. The lens sub unit L42 corresponds to the twenty-eighth surface to the thirtieth surface, and includes a cemented lens formed of a biconvex lens and a biconcave lens. The fifth lens unit L5 corresponds to the thirty-first surface to the thirty-fifth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side, and a biconvex lens.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (6) and the expressions (8) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 89.2 degrees at the wide angle end.
In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 9
FIG. 17 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 9 (Numerical Embodiment 9) of the present invention. FIG. 18A, FIG. 18B, and FIG. 18C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 30 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 17, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L42 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured to not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit L11 having a negative refractive power, and being configured not to move for focusing, and a lens sub unit L12 having a negative refractive power, and being configured to move toward the object side during focusing from an infinity side to a proximity side. The lens sub unit (L11) includes a concave meniscus lens that is convex toward the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit (L12) includes, in order from the object side to the image side, a biconcave lens and a biconvex lens. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the seventh surface to the ninth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the tenth surface and the eleventh surface, and includes a biconvex lens. Moreover, the tenth surface has an aspherical shape to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the twelfth surface to the seventeenth surface, and includes the aperture stop, a cemented lens formed of a biconcave lens and a convex meniscus lens having a convex surface on the object side, and a biconcave lens. The lens sub unit L41 corresponds to the eighteenth surface and the nineteenth surface, and includes a biconvex lens. The lens sub unit L42 corresponds to the twentieth surface to the twenty-second surface, and includes a cemented lens formed of a convex meniscus lens having a convex surface on the image side and a concave meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-third surface to the twenty-fifth surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (5), and the expressions (7) to (9) to achieve a wide angle of view with a photographing angle of view (angle of view) of 85.6 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 10
FIG. 19 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 10 (Numerical Embodiment 10) of the present invention. FIG. 20A, FIG. 20B, and FIG. 20C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 17 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 19, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The lens sub unit L21 and the lens sub unit L22 are configured to move along loci that are different from each other during zooming. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a lens sub unit L41 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L42 for magnification varying, which is configured to move during zooming from the wide angle end to the telephoto end, and has a negative refractive power. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured to not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the sixth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit L12 having a positive refractive power, and being configured to move toward the image side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side, a concave meniscus lens having a convex surface on the object side, a biconcave lens, and a convex meniscus lens having a convex surface on the object side. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side to the image side, a biconvex lens and a concave meniscus lens having a concave surface on the image side. The lens sub unit L21, which is one lens sub unit of the second lens unit L2, corresponds to the thirteenth surface to the fifteenth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22, which is another lens sub unit of the second lens unit L2, corresponds to the sixteenth surface and the seventeenth surface, and includes a biconvex lens. Moreover, the sixteenth surface and the seventeenth surface have aspherical shapes to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the eighteenth surface to the twenty-third surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a biconvex lens, and a biconcave lens. The lens sub unit L41 corresponds to the twenty-fourth surface to the twenty-seventh surface, and includes a convex meniscus lens having a convex surface on the image side, and a biconvex lens. The lens sub unit L42 corresponds to the twenty-eighth surface to the thirtieth surface, and includes a cemented lens formed of a biconvex lens and a biconcave lens. The fifth lens unit L5 corresponds to the thirty-first surface to the thirty-third surface, and includes a cemented lens formed of a biconvex lens and a concave meniscus lens having a concave surface on the object side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (6) and the expressions (8) to (10) to achieve a wide angle of view with a photographing angle of view (angle of view) of 114.6 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
Embodiment 11
FIG. 21 is a lens cross-sectional view when the focus is at the infinity at the wide angle end in the zoom lens according to Embodiment 11 (Numerical Embodiment 11) of the present invention. FIG. 22A, FIG. 22B, and FIG. 22C are respectively longitudinal aberration diagrams at the wide angle end, a focal length of 15 mm, and the telephoto end. Each of the aberration diagrams is the longitudinal aberration diagram when the focus is at the infinity. In FIG. 21, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 for focusing, which has a negative refractive power. The zoom lens further includes a lens sub unit L21 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a lens sub unit L22 for magnification varying, which is configured to move toward the object side during zooming from the wide angle end to the telephoto end, and has a positive refractive power. The zoom lens further includes a third lens unit L3 having a negative refractive power, and being configured not to move for zooming. The zoom lens further includes a fourth lens unit L4 having a positive refractive power, and being configured to move nonlinearly on the optical axis in conjunction with the movements of the lens sub unit L21 and the lens sub unit L22 to correct an image plane variation accompanying zooming. The zoom lens further includes a fifth lens unit L5 having a positive refractive power, being configured not to move for zooming, and having an image forming action.
Next, the first lens unit L1 in this Embodiment is described. The first lens unit L1 corresponds to the first surface to the twelfth surface. The first lens unit L1 includes a lens sub unit (L11) having a negative refractive power, and being configured not to move for focusing, and a lens sub unit (L12) having a positive refractive power, and being configured to move toward the image side during focusing from an infinity side to a proximity side. The lens sub unit L11 includes a concave meniscus lens having a convex surface on the object side, a concave meniscus lens having a convex surface on the object side, a biconcave lens, and a biconvex lens. Moreover, the first surface has an aspherical shape to mainly correct distortion and field curvature on the wide angle side. The lens sub unit L12 includes, in order from the object side, a biconvex lens and a concave meniscus lens having a convex surface on the object side. The lens sub unit L21 corresponds to the thirteenth surface to the fifteenth surface, and includes a cemented lens formed of a concave meniscus lens having a convex surface on the object side and a biconvex lens. The lens sub unit L22 corresponds to the sixteenth surface and the seventeenth surface, and includes a biconvex lens. Moreover, the sixteenth surface and the seventeenth surface have aspherical shapes to mainly correct variations in spherical aberration and field curvature accompanying zooming. The third lens unit L3 corresponds to the eighteenth surface to the twenty-third surface, and includes an aperture stop, a cemented lens formed of a biconcave lens and a biconvex lens, and a biconcave lens. The fourth lens unit L4 corresponds to the twenty-fourth surface and the twenty-fifth surface, and includes a convex meniscus lens having a convex surface on the image side. The fifth lens unit L5 corresponds to the twenty-sixth surface to the thirty-third surface, and includes a biconvex lens, a cemented lens formed of a convex meniscus lens having a convex surface on the object side and a concave meniscus lens having a convex surface on the object side, and a cemented lens formed of a biconvex lens and a concave meniscus lens having a convex surface on the image side.
Values corresponding to respective conditional expressions of this Embodiment are shown in Table 1. This Embodiment satisfies the expressions (1) to (6) and the expressions (8) to (11) to achieve a wide angle of view with a photographing angle of view (angle of view) of 112 degrees at the wide angle end. In addition, the zoom lens having the high optical performance, in which various aberrations are satisfactorily corrected over the entire zoom range, is realized.
The exemplary embodiments of the present invention have been described above. However, it is to be understood that the present invention is not limited to the exemplary embodiments and various modifications and changes may be made without departing from the gist of the present invention.










(Numerical Embodiment 1)


Unit mm







Surface data













Surface








number





Effective


i
ri
di
ndi
vdi
θgFi
diameter





 1*
81.541
2.00
1.516330
64.14
0.5352
66.0


 2
27.668
29.11 



51.2


 3
−106.430
2.21
1.800000
29.84
0.6017
45.1


 4
61.512
3.30



42.5


 5
69.810
4.46
1.846660
23.78
0.6205
42.6


 6
1,314.349
(Variable)



42.3


 7
62.618
1.50
1.800000
29.84
0.6017
33.9


 8
34.394
7.04
1.563839
60.67
0.5402
33.9


 9
−104.184
(Variable)



34.1


10*
77.774
5.13
1.438750
94.93
0.5343
34.9


11*
−75.732
(Variable)



34.8


12
0.000
1.84



17.9


13
−43.859
1.00
1.603112
60.64
0.5414
17.6


14
26.489
2.68
1.784696
26.29
0.6135
17.5


15
522.448
1.05



17.3


16
−70.742
1.00
1.696797
55.53
0.5433
17.3


17
65.636
2.64



17.3


18
0.000
(Variable)



17.7


19
81.328
8.34
1.537750
74.70
0.5393
22.5


20
−19.512
1.00
1.567322
42.80
0.5730
23.8


21
−44.224
(Variable)



25.0


22
52.647
1.00
1.517417
52.43
0.5564
25.9


23
22.309
5.93
1.677900
55.34
0.5472
25.9


24
−316.191
0.47



25.6


25
61.102
1.42
1.762001
40.10
0.5765
25.0


26
21.416
3.78



23.7


27
23.336
8.40
1.438750
94.93
0.5343
25.3


28
−28.213
1.00
1.834807
42.71
0.5642
25.0


29
−201.209
BF



25.4


Image
∞


plane










Aspherical surface data





First surface









K = 3.48534e+000
A4 = 1.71640e−006
A6 = 8.41226e−011


A8 = −2.56285e−013
A10 = 2.79463e−016
A12 = −4.19689e−020







Tenth surface









K = −7.08167e+000
A4 = −6.61607e−007
A6 = 2.90014e−009


A8 = −4.66899e−011
A10 = 2.03286e−013
A12 = −3.43592e−016







Eleventh surface









K = 1.64127e+000
A4 = −1.04152e−006
A6 = 2.33336e−009


A8 = −3.26813e−011
A10 = 1.53684e−013
A12 = −2.80962e−016










Various data


Zoom ratio 4.32













Wide angle
Intermediate
Telephoto







Focal length
18.50
30.00
80.00



F-number
4.00
4.00
4.00



Half angle of
38.66
26.26
10.48



view



Image height
14.80
14.80
14.80



Total lens
217.12
217.12
217.12



length



BF
43.55
43.55
43.55



d6
58.51
29.34
1.77



d9
0.64
16.69
5.01



d11
0.40
13.52
52.78



d18
17.21
15.02
0.23



d21
0.50
2.68
17.48











Zoom lens unit data









Unit
First surface
Focal length





1
1
−43.50


21
7
89.33


22
10
88.13


3
12
−33.91


4
19
57.16


5
22
135.77



















(Numerical Embodiment 2)


Unit mm





















Surface








number





Effective


i
ri
di
ndi
vdi
θgFi
diameter





 1*
87.610
2.00
1.618000
63.33
0.5441
67.6


 2
25.663
29.11 



49.3


 3
−64.303
1.50
1.688931
31.07
0.6003
43.6


 4
38.210
8.20
1.761821
26.52
0.6135
40.6


 5
7,032.775
(Variable)



39.9


 6
71.196
1.50
1.800000
29.84
0.6017
34.8


 7
40.515
9.25
1.516330
64.14
0.5352
35.0


 8
−92.106
(Variable)



35.9


 9*
52.192
8.27
1.438750
94.93
0.5343
38.6


10*
−62.342
(Variable)



38.5


11
0.000
2.25



22.0


12
−44.095
1.00
1.677900
55.34
0.5472
21.6


13
25.191
3.21
1.805181
25.42
0.6161
21.5


14
172.645
1.20



21.4


15
−95.195
1.00
1.563839
60.67
0.5402
21.3


16
71.541
2.64



21.4


17
0.000
(Variable)



21.8


18
87.917
6.68
1.496999
81.54
0.5374
24.6


19
−22.325
1.00
1.567322
42.80
0.5730
25.3


20
−48.853
(Variable)



26.6


21
137.912
3.68
1.696797
55.53
0.5433
28.5


22
−66.880
0.47



28.7


23
37.293
5.44
1.496999
81.54
0.5374
28.1


24
−81.948
1.42
1.772499
49.60
0.5521
27.5


25
31.067
4.00



26.2


26
37.971
7.07
1.438750
94.93
0.5343
27.3


27
−31.802
1.00
1.698947
30.13
0.6029
27.3


28
−126.994
BF



27.7


Image
∞


plane










Aspherical surface data





First surface









K = 4.43141e+000
A4 = 2.11208e−006
A6 = 4.04346e−010


A8 = −1.01973e−012
A10 = 9.65526e−016
A12 = −2.57329e−019







Ninth surface









K = −2.70928e+000
A4 = 7.09063e−007
A6 = 3.32149e−009


A8 = −4.15992e−011
A10 = 1.59397e−013
A12 = −2.27454e−016







Tenth surface









K = −1.00005e+000
A4 = 2.18074e−007
A6 = 2.07516e−009


A8 = −3.06266e−011
A10 = 1.23962e−013
A12 = −1.87509e−016










Various data


Zoom ratio 3.00













Wide angle
Intermediate
Telephoto







Focal length
15.50
27.00
46.50



F-number
2.70
2.70
2.70



Half angle of
43.68
28.73
17.65



view



Image height
14.80
14.80
14.80



Total lens
215.06
215.06
215.06



length



BF
40.00
40.00
40.00



d5
54.69
22.82
8.77



d8
0.62
15.33
9.45



d10
0.00
17.17
37.11



d17
17.47
15.00
6.13



d20
0.39
2.86
11.73











Zoom lens unit data









Unit
First surface
Focal length





1
1
−33.20


21
6
103.00


22
9
66.04


3
11
−33.80


4
18
72.00


5
21
85.36



















(Numerical Embodiment 3)


Unit mm







Surface data



















Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
100.823
2.70
1.537750
74.70
0.5393
64.4


 2
27.752
31.15 



49.4


 3
−150.390
1.50
1.729157
54.68
0.5444
44.7


 4
57.570
0.72



41.7


 5
56.104
8.21
1.658441
50.88
0.5561
41.6


 6
−1,072.608
(Variable)



40.0


 7
238.625
5.88
1.620411
60.29
0.5426
22.8


 8
−33.607
1.35
1.761821
26.52
0.6135
23.3


 9
−61.887
0.20



23.7


10
47.633
4.36
1.438750
94.93
0.5343
23.9


11
−169.496
(Variable)



23.5


12
0.000
1.71



15.9


13
−58.082
0.80
1.696797
55.53
0.5433
15.6


14
29.770
1.79
1.959060
17.47
0.6599
15.5


15
53.667
1.95



15.4


16
−24.477
1.20
1.516330
64.14
0.5352
15.4


17
40.606
(Variable)



16.3


18*
32.752
6.62
1.496999
81.54
0.5374
18.2


19
−32.730
(Variable)



20.2


20
76.090
0.97
1.785896
44.20
0.5631
28.3


21
38.996
9.33
1.496999
81.54
0.5374
28.5


22
−36.584
(Variable)



29.4


23
38.989
10.10 
1.496999
81.54
0.5374
29.1


24
−26.754
0.90
1.910820
35.25
0.5824
28.1


25
−399.882
BF



28.3


Image
∞


plane










Aspherical surface data





First surface









K = 2.99107e+000
A4 = 2.16207e−006
A6 = 4.17797e−010


A8 = −8.79919e−013
A10 = 1.00331e−015
A12 = −2.48813e−019







Eighteenth surface









K = 0.00000e+000
A4 = −1.25438e−005
A6 = 3.43408e−008


A8 = −5.64880e−010
A10 = 4.07328e−012
A12 = −1.08661e−014










Various data


Zoom ratio 2.67













Wide angle
Intermediate
Telephoto







Focal length
18.00
36.00
48.00



F-number
2.94
3.21
3.50



Half angle of
39.43
22.35
17.14



view



Image height
14.80
14.80
14.80



Total lens
187.91
187.91
187.91



length



BF
40.95
40.95
40.95



d6
32.02
11.11
3.37



d11
1.32
22.23
29.97



d17
6.95
3.59
2.42



d19
14.74
9.74
4.14



d22
0.49
8.85
15.61



d25
40.95
40.95
40.95











Zoom lens unit data









Unit
First surface
Focal length





1
1
−47.91


2
7
45.08


3
12
−17.49


41
18
33.98


42
20
61.56


5
23
1705.24



















(Numerical Embodiment 4)


Unit mm





















Surface








number





Effective


i
ri
di
ndi
vdi
θgFi
diameter





 1*
158.682
2.70
1.487490
70.23
0.5300
57.0


 2
21.477
23.52 



40.1


 3
−65.332
1.50
1.729157
54.68
0.5444
36.0


 4
116.976
3.57



34.5


 5
111.421
5.23
1.696797
55.53
0.5433
33.5


 6
−332.807
(Variable)



32.5


 7
67.228
6.45
1.618000
63.33
0.5441
24.7


 8
−38.833
1.35
1.800000
29.84
0.6017
24.6


 9
−121.222
(Variable)



25.0


10*
68.223
5.44
1.496999
81.54
0.5374
25.4


11
−49.716
(Variable)



25.3


12
0.000
1.67



14.2


13
−80.222
0.80
1.729157
54.68
0.5444
13.8


14
19.087
2.46
1.808095
22.76
0.6307
13.6


15
120.749
4.52



13.4


16
−26.029
0.80
1.804000
46.58
0.5572
12.9


17
403.345
(Variable)



13.1


18*
82.237
6.17
1.496999
81.54
0.5374
20.9


19
−25.255
(Variable)



22.4


20
550.937
5.26
1.595220
67.74
0.5442
23.5


21
−22.821
0.90
1.953750
32.32
0.5898
23.8


22
−45.694
0.38



24.7


23
70.482
5.99
1.496999
81.54
0.5374
25.2


24
−25.120
0.90
1.882997
40.76
0.5667
25.1


25
−69.445
BF



25.8


Image
∞


plane










Aspherical surface data





First surface









K = 2.99107e+000
A4 = 7.33965e−006
A6 = −4.16481e−009


A8 = 6.68382e−012
A10 = −5.59885e−015
A12 = 2.90870e−018







Tenth surface









K = 0.00000e+000
A4 = −4.67248e−006
A6 = 4.65010e−009


A8 = −4.88533e−011
A10 = 1.99102e−013
A12 = −3.03795e−016







Eighteenth surface









K = 0.00000e+000
A4 = 1.67124e−006
A6 = 7.12145e−009


A8 = −7.61635e−011
A10 = 9.72722e−013
A12 = −4.78927e−015










Various data


Zoom ratio 3.03













Wide angle
Intermediate
Telephoto







Focal length
16.50
35.00
50.00



F-number
3.26
3.58
4.00



Half angle of
41.89
22.92
16.49



view



Image height
14.80
14.80
14.80



Total lens
181.46
181.46
181.46



length



BF
49.44
49.44
49.44



d6
36.41
8.50
4.13



d9
1.49
7.21
1.50



d11
1.96
24.15
34.23



d17
11.55
8.42
4.61



d19
0.99
4.13
7.93











Zoom lens unit data









Unit
First surface
Focal length





1
1
−32.12


21
7
90.93


22
10
58.59


3
12
−21.41


4
18
39.52


5
20
92.47



















(Numerical Embodiment 5)


Unit mm



























Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
78.308
2.80
1.696797
55.53
0.5433
69.9


 2
27.219
24.45 



51.2


 3
−79.342
1.89
1.834807
42.71
0.5642
45.7


 4
44.444
6.23



42.2


 5
59.865
5.39
1.603420
38.03
0.5835
43.5


 6
1,100.405
1.12



43.4


 7
223.596
6.06
1.670029
47.23
0.5627
43.0


 8
−66.545
0.98



42.7


 9
−16,548.304
1.68
1.850259
32.27
0.5929
38.7


10
94.834
(Variable)



37.1


11
60.076
1.50
1.800000
29.84
0.6017
32.1


12
36.337
8.61
1.516330
64.14
0.5352
32.1


13
−98.591
(Variable)



32.7


14*
58.909
5.63
1.438750
94.93
0.5343
34.1


15*
−76.762
(Variable)



34.0


16
0.000
2.22



20.0


17
−50.435
1.00
1.696797
55.53
0.5433
19.5


18
24.837
3.23
1.805181
25.42
0.6161
19.4


19
1,307.515
1.21



19.3


20
−43.003
1.00
1.516330
64.14
0.5352
19.2


21
73.586
(Variable)



19.4


22
138.037
6.82
1.438750
94.93
0.5343
20.8


23
−22.944
0.80
1.570989
50.80
0.5588
22.4


24
−31.987
(Variable)



23.2


25
31.163
5.92
1.438750
94.93
0.5343
28.8


26
−114.255
0.47



28.7


27
42.475
0.80
1.754998
52.32
0.5476
27.8


28
22.665
1.50



26.6


29
25.682
8.72
1.438750
94.93
0.5343
26.9


30
−27.612
0.80
1.755199
27.51
0.6103
26.7


31
−334.957
BF



26.9


Image
∞


plane










Aspherical surface data





First surface









K = 3.32755e+000
A4 = 1.67794e−006
A6 = 5.55468e−010


A8 = −1.45838e−012
A10 = 1.26290e−015
A12 = −3.79497e−019







Fourteenth surface









K = −4.14953e−001
A4 = −1.25538e−006
A6 = 5.56134e−009


A8 = −5.52273e−011
A10 = 2.62913e−013
A12 = −4.61916e−016







Fifteenth surface









K = −4.09299e−001
A4 = −5.64796e−007
A6 = 3.69251e−009


A8 = −3.42012e−011
A10 = 1.85309e−013
A12 = −3.60826e−016










Various data


Zoom ratio 3.00













Wide angle
Intermediate
Telephoto







Focal length
13.00
25.00
39.00



F-number
2.79
2.86
3.00



Half angle of
48.70
30.63
20.78



view



Image height
14.80
14.80
14.80



Total lens
220.00
220.00
220.00



length



BF
40.00
40.00
40.00



d10
53.87
19.30
7.28



d13
0.50
15.30
10.60



d15
0.47
20.23
36.95



d21
17.06
12.48
5.24



d24
7.29
11.87
19.11











Zoom lens unit data









Unit
First surface
Focal length





1
1
−30.26


21
11
94.22


22
14
76.75


3
16
−33.52


4
22
66.10


5
25
84.40



















(Numerical Embodiment 6)


Unit mm







Surface data



















Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
105.156
2.70
1.496999
81.54
0.5374
63.3


 2
24.557
(Variable)



46.2


 3
−79.541
1.50
1.740999
52.64
0.5467
38.7


 4
100.713
3.59



36.8


 5
100.339
3.68
1.698947
30.13
0.6029
35.7


 6
−1,203.013
(Variable)



35.0


 7
62.920
7.59
1.618000
63.33
0.5441
28.3


 8
−42.666
1.35
1.854780
24.80
0.6122
28.0


 9
−108.523
0.20



28.0


10*
73.558
7.56
1.496999
81.54
0.5374
27.5


11
−56.908
(Variable)



26.4


12
0.000
2.90



12.7


13
−55.809
0.80
1.658441
50.88
0.5561
12.0


14
15.148
2.12
1.922860
18.90
0.6495
11.8


15
41.652
3.18



11.5


16
−19.790
1.50
1.800000
29.84
0.6017
11.3


17
−261.806
(Variable)



11.8


18*
192.872
3.54
1.496999
81.54
0.5374
15.8


19
−18.940
(Variable)



16.7


20
160.222
6.54
1.595220
67.74
0.5442
18.4


21
−13.803
0.90
1.910820
35.25
0.5824
19.1


22
−37.294
0.20



20.8


23
146.359
4.47
1.595220
67.74
0.5442
21.8


24
−64.006
BF



22.5


Image
∞


plane










Aspherical surface data





First surface









K = 2.99107e+000
A4 = 4.02739e−006
A6 = −8.89153e−010


A8 = 1.66414e−012
A10 = −1.31092e−015
A12 = 8.65049e−019







Tenth surface









K = 0.00000e+000
A4 = −3.86204e−006
A6 = 2.47475e−009


A8 = −2.42565e−011
A10 = 9.35867e−014
A12 = −1.36600e−016







Eighteenth surface









K = 0.00000e+000
A4 = 6.13749e−006
A6 = 2.62274e−008


A8 = 8.14687e−010
A10 = −1.19700e−011
A12 = 5.17898e−014










Various data


Zoom ratio 3.24













Wide angle
Intermediate
Telephoto







Focal length
17.00
35.00
55.00



F-number
3.44
3.75
4.00



Half angle of
41.04
22.92
15.06



view



Image height
14.80
14.80
14.80



Total lens
174.07
174.07
174.07



length



BF
45.95
45.95
45.95



d2
29.28
36.15
26.78



d6
36.41
7.33
1.70



d11
1.98
24.19
39.18



d17
5.15
2.65
0.57



d19
1.00
3.50
5.58



d24
45.95
45.95
45.95











Zoom lens unit data









Unit
First surface
Focal length





1
1
−65.00


21
3
−115.33


22
7
38.59


3
12
−18.00


4
18
34.79


5
20
54.27



















(Numerical Embodiment 7)


Unit mm







Surface data



















Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
139.603
2.70
1.496999
81.54
0.5374
60.4


 2
22.128
23.73 



42.0


 3
−69.393
1.50
1.729157
54.68
0.5444
37.2


 4
84.529
3.44



35.3


 5
80.615
5.91
1.651597
58.55
0.5426
34.4


 6
−3,630.207
(Variable)



33.1


 7
163.620
7.50
1.639300
44.87
0.5684
31.3


 8
−31.897
1.35
1.805181
25.42
0.6161
31.9


 9
−68.026
(Variable)



33.1


10*
48.822
8.18
1.438750
94.93
0.5343
34.5


11
−52.537
(Variable)



34.4


12
0.000
2.25



19.4


13
−89.826
0.80
1.834807
42.73
0.5648
18.7


14
19.759
3.51
1.846660
23.78
0.6205
18.3


15
270.773
3.92



18.2


16
−24.598
1.20
1.517417
52.43
0.5564
17.8


17
112.189
(Variable)



18.4


18*
200.164
5.93
1.438750
94.93
0.5343
19.1


19
−27.985
(Variable)



21.2


20
−669.709
5.82
1.595220
67.74
0.5442
25.9


21
−25.307
0.90
2.003300
28.27
0.5980
26.6


22
−39.511
(Variable)



27.7


23
65.278
6.98
1.595220
67.74
0.5442
29.0


24
−31.268
0.90
1.953750
32.32
0.5898
29.0


25
−80.489
BF



29.5


Image
∞


plane










Aspherical surface data





First surface









K = 2.99107e+000
A4 = 6.19159e−006
A6 = −3.22667e−009


A8 = 5.52229e−012
A10 = −4.81977e−015
A12 = 2.37317e−018







Tenth surface









K = 0.00000e+000
A4 = −3.88179e−006
A6 = 6.19439e−009


A8 = −4.66883e−011
A10 = 1.38796e−013
A12 = −1.53199e−016







Eighteenth surface









K = 0.00000e+000
A4 = 2.80480e−006
A6 = −3.17920e−008


A8 = 6.38976e−010
A10 = −5.01093e−012
A12 = 1.41630e−014










Various data


Zoom ratio 2.97













Wide angle
Intermediate
Telephoto







Focal length
15.50
27.00
46.00



F-number
2.54
2.65
2.80



Half angle of
43.68
28.73
17.84



view



Image height
14.80
14.80
14.80



Total lens
186.31
186.31
186.31



length



BF
42.55
42.55
42.55



d6
36.83
11.75
2.35



d9
1.44
10.29
1.46



d11
2.40
18.62
36.85



d17
8.65
6.79
2.17



d19
7.16
3.71
1.78



d22
0.77
6.08
12.63



d25
42.55
42.55
42.55











Zoom lens unit data









Unit
First surface
Focal length





1
1
−30.13


21
7
95.80


22
10
58.99


3
12
−25.40


41
18
56.27


42
20
116.71


5
23
105.68



















(Numerical Embodiment 8)


Unit mm







Surface data



















Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
56.472
2.80
1.651597
58.55
0.5426
54.0


 2
28.188
6.20



45.0


 3
32.615
2.00
1.729157
54.68
0.5444
41.1


 4
21.980
13.32 



35.2


 5
−49.732
1.80
1.496999
81.54
0.5374
33.4


 6
37.332
1.31



30.4


 7
51.024
4.83
1.647689
33.79
0.5939
30.4


 8
117.338
1.81



29.3


 9
−272.351
3.93
1.516330
64.14
0.5352
29.1


10
−43.468
2.50



28.8


11
−528.451
1.68
1.922860
18.90
0.6495
25.1


12
241.848
(Variable)



24.4


13
45.558
1.50
2.000690
25.46
0.6133
27.4


14
33.237
5.25
1.595220
67.74
0.5442
27.2


15
−106.481
(Variable)



27.4


16*
40.571
5.55
1.496999
81.54
0.5374
27.7


17*
−69.990
(Variable)



27.6


18
0.000
3.00



16.9


19
−79.784
1.00
1.882997
40.76
0.5667
15.7


20
15.234
3.46
1.808095
22.76
0.6307
15.1


21
−686.219
1.16



15.0


22
−35.503
1.00
1.816000
46.62
0.5568
14.9


23
60.738
(Variable)



15.0


24
−187.450
4.00
1.537750
74.70
0.5393
25.4


25
−30.075
0.20



26.4


26
33.121
6.32
1.438750
94.93
0.5343
31.2


27
−215.883
(Variable)



31.4


28
66.857
3.35
1.922860
18.90
0.6495
31.5


29
−2,017.462
1.00
2.000690
25.46
0.6133
31.3


30
29.686
(Variable)



30.2


31
48.297
8.50
1.729157
54.68
0.5444
31.0


32
−33.333
0.80
2.000690
25.46
0.6133
31.4


33
−118.506
0.20



32.5


34
114.930
5.50
1.537750
74.70
0.5393
33.4


35
−67.536
BF



33.7


Image
∞


plane










Aspherical surface data





First surface









K = 2.25376e+000
A4 = 2.38111e−006
A6 = −5.36706e−010


A8 = −1.36021e−012
A10 = 2.70681e−015
A12 = −1.78443e−018







Sixteenth surface









K = −8.03251e−001
A4 = −4.09302e−006
A6 = 1.86617e−008


A8 = −5.14357e−010
A10 = 3.51384e−012
A12 = −1.06379e−014







Seventeenth surface









K = 4.88557e−001
A4 = −4.09768e−006
A6 = −6.59431e−010


A8 = −2.19670e−010
A10 = 1.82277e−012
A12 = −6.89510e−015










Various data


Zoom ratio 3.00













Wide angle
Intermediate
Telephoto







Focal length
15.00
30.00
45.00



F-number
2.41
2.90
3.50



Half angle of
44.62
26.26
18.21



view



Image height
14.80
14.80
14.80



Total lens
178.97
178.97
178.97



length



BF
41.00
41.00
41.00



d12
24.52
8.68
4.72



d15
0.50
3.15
0.50



d17
0.40
13.59
20.20



d23
14.65
8.41
2.27



d27
1.59
6.24
11.64



d30
2.36
3.95
4.68



d35
41.00
41.00
41.00











Zoom lens unit data









Unit
First surface
Focal length





1
1
−27.42


21
13
65.39


22
16
52.40


3
18
−18.70


41
24
32.98


42
28
−52.56


5
31
37.85



















(Numerical Embodiment 9)


Unit mm







Surface data













Surface








number





Effective


i
ri
di
ndi
vdi
θgFi
diameter





 1*
140.746
2.70
1.487490
70.23
0.5300
60.1


 2
21.653
27.58 



41.5


 3
−61.487
1.50
1.719995
50.23
0.5521
33.7


 4
82.175
2.30



32.1


 5
76.776
5.80
1.651597
58.55
0.5426
31.5


 6
−886.071
(Variable)



30.3


 7
152.802
7.08
1.613397
44.30
0.5633
24.0


 8
−30.721
1.35
1.805181
25.42
0.6161
24.0


 9
−69.806
(Variable)



24.3


10*
51.136
6.23
1.496999
81.54
0.5374
25.2


11
−49.958
(Variable)



25.1


12
0.000
1.70



13.8


13
−45.913
0.80
1.834807
42.73
0.5648
13.4


14
14.211
4.64
1.846660
23.78
0.6205
13.4


15
532.716
4.79



13.3


16
−17.516
1.20
1.517417
52.43
0.5564
13.2


17
5,082.028
(Variable)



13.8


18
261.670
2.95
1.595220
67.74
0.5442
14.0


19
−23.638
(Variable)



15.0


20
−110.686
3.77
1.595220
67.74
0.5442
15.9


21
−16.345
0.90
2.003300
28.27
0.5980
16.5


22
−21.793
(Variable)



17.2


23
126.887
4.76
1.595220
67.74
0.5442
17.7


24
−19.855
0.90
1.953750
32.32
0.5898
17.8


25
−77.053
BF



18.4


Image
∞


plane










Aspherical surface data





First surface









K = 2.99107e+000
A4 = 6.86067e−006
A6 = −4.69819e−009


A8 = 8.70648e−012
A10 = −8.07592e−015
A12 = 3.85102e−018







Tenth surface









K = 0.00000e+000
A4 = −4.23189e−006
A6 = 5.49762e−009


A8 = −5.93754e−011
A10 = 2.58567e−013
A12 = −4.29357e−016










Various data


Zoom ratio 3.00













Wide angle
Intermediate
Telephoto







Focal length
16.00
30.00
48.00



F-number
3.75
3.82
4.00



Half angle of
42.77
26.26
17.14



view



Image height
14.80
14.80
14.80



Total lens
176.48
176.48
176.48



length



BF
48.84
48.84
48.84



d6
36.52
8.57
1.79



d9
1.45
10.25
1.74



d11
3.34
22.49
37.78



d17
4.04
2.99
0.54



d19
0.93
1.07
0.82



d22
0.41
1.31
4.02



d25
48.84
48.84
48.84











Zoom lens unit data









Unit
First surface
Focal length





1
1
−28.62


21
7
108.40


22
10
51.76


3
12
−18.92


41
18
36.44


42
20
60.28


5
23
−1031.32



















(Numerical Embodiment 10)


Unit mm







Surface data



















Effec-


Surface





tive


number





diam-


i
ri
di
ndi
vdi
θgFi
eter





 1*
68.920
2.80
1.696797
55.53
0.5433
74.0


 2
27.500
19.53 



54.2


 3
59.092
1.89
1.882997
40.76
0.5667
48.8


 4
22.937
13.21 



38.1


 5
−69.447
1.00
1.496999
81.54
0.5374
37.7


 6
43.559
7.71



35.7


 7
52.134
5.68
1.548141
45.79
0.5685
36.1


 8
233.916
1.16



35.4


 9
2,1674.176
5.22
1.517417
52.43
0.5564
35.3


10
−42.786
1.50



35.1


11
2,579.545
1.68
1.953750
32.32
0.5898
30.7


12
105.490
(Variable)



29.6


13
44.612
1.50
2.000690
25.46
0.6133
31.6


14
29.993
6.14
1.531717
48.84
0.5630
31.1


15
−382.107
(Variable)



31.4


16*
50.848
6.27
1.438750
94.93
0.5343
32.0


17*
−53.169
(Variable)



32.0


18
0.000
3.00



18.9


19
−65.174
1.00
1.834807
42.73
0.5648
18.1


20
16.794
5.49
1.808095
22.76
0.6307
17.9


21
−45.168
2.29



17.9


22
−27.765
1.00
2.000690
25.46
0.6133
17.1


23
3,868.913
(Variable)



17.4


24
−64.588
3.17
1.595220
67.74
0.5442
19.3


25
−29.313
1.90



19.9


26
54.084
4.27
1.595220
67.74
0.5442
22.6


27
−40.151
(Variable)



22.8


28
62.164
4.63
1.548141
45.79
0.5685
22.6


29
−30.099
1.00
1.953750
32.32
0.5898
22.3


30
37.465
(Variable)



22.4


31
38.870
8.48
1.595220
67.74
0.5442
23.1


32
−28.000
0.80
1.953750
32.32
0.5898
23.9


33
−47.730
BF



24.5


Image
∞


plane










Aspherical surface data





First surface









K = 2.25376e+000
A4 = 3.25133e−006
A6 = −3.03483e−009


A8 = 3.88387e−012
A10 = −2.64826e−015
A12 = 8.36141e−019







Sixteenth surface









K = −8.03251e−001
A4 = −3.18540e−006
A6 = 2.90027e−008


A8 = −2.24588e−010
A10 = 8.34708e−013
A12 = −1.19390e−015







Seventeenth surface









K = 4.88557e−001
A4 = −5.19876e−007
A6 = 2.49381e−008


A8 = −1.96367e−010
A10 = 7.56868e−013
A12 = −1.11249e−015










Various data


Zoom ratio 2.63













Wide angle
Intermediate
Telephoto







Focal length
9.50
17.00
25.00



F-number
2.77
2.80
2.80



Half angle of
57.30
41.04
30.63



view



Image height
14.80
14.80
14.80



Total lens
211.00
211.00
211.00



length



BF
41.00
41.00
41.00



d12
41.58
12.33
5.01



d15
0.50
9.48
0.50



d17
0.40
20.67
36.97



d23
13.52
10.76
7.35



d27
0.87
1.40
1.35



d30
0.80
3.03
6.49



d33
41.00
41.00
41.00











Zoom lens unit data









Unit
First surface
Focal length





1
1
−20.00


21
13
119.29


22
16
60.20


3
18
−29.98


41
24
27.45


42
28
−34.00


5
31
45.65



















(Numerical Embodiment 11)


Unit mm





















Surface








number





Effective


i
ri
di
ndi
vdi
θgFi
diameter





 1*
67.946
2.80
1.696797
55.53
0.5433
72.7


 2
28.157
13.53 



54.6


 3
40.584
1.89
1.882997
40.76
0.5667
50.9


 4
23.608
15.83 



41.0


 5
−78.101
1.89
1.834000
37.16
0.5775
39.1


 6
44.678
8.13



36.5


 7
79.057
4.47
1.620041
36.26
0.5879
37.7


 8
−248.175
0.98



37.6


 9
91.566
6.10
1.548141
45.79
0.5685
36.8


10
−61.074
0.94



36.3


11
352.619
1.68
2.001000
29.13
0.5997
32.5


12
67.819
(Variable)



31.1


13
47.930
1.50
2.000690
25.46
0.6133
30.9


14
30.990
6.64
1.531717
48.84
0.5630
30.6


15
−89.014
(Variable)



30.9


16*
52.411
6.30
1.438750
94.93
0.5343
32.6


17*
−52.471
(Variable)



32.5


18
0.000
2.09



19.9


19
−54.033
1.00
1.754998
52.32
0.5476
19.4


20
16.760
4.73
1.784696
26.29
0.6135
19.0


21
−80.459
0.90



18.9


22
−34.770
1.00
1.740999
52.64
0.5467
18.8


23
75.109
(Variable)



18.9


24
−182.656
2.90
1.496999
81.54
0.5374
20.4


25
−32.694
(Variable)



20.7


26
31.755
4.61
1.438750
94.93
0.5343
22.1


27
−66.019
0.47



22.3


28
37.171
3.00
1.438750
94.93
0.5343
22.3


29
389.443
1.00
1.799516
42.22
0.5672
22.0


30
23.611
3.00



21.5


31
28.993
7.27
1.438750
94.93
0.5343
23.1


32
−22.987
0.80
1.922860
18.90
0.6495
23.3


33
−40.782
BF



24.1


Image
∞


plane










Aspherical surface data





First surface









K = 2.25376e+000
A4 = 2.28704e−006
A6 = −6.70875e−010


A8 = 9.77567e−013
A10 = −9.03399e−016
A12 = 4.23368e−019







Sixteenth surface









K = −8.03251e−001
A4 = −9.36601e−007
A6 = 8.10468e−009


A8 = −7.98653e−011
A10 = 3.52905e−013
A12 = −5.55071e−016







Seventeenth surface









K = 4.88557e−001
A4 = 8.32579e−007
A6 = 3.66737e−009


A8 = −4.26926e−011
A10 = 2.26611e−013
A12 = −4.00394e−016










Various data


Zoom ratio 2.50











Wide angle
Intermediate
Telephoto





Focal length
10.00
15.00
25.00


F-number
2.67
2.68
2.70


Half angle of
55.95
44.61
30.63


view


Image height
14.80
14.80
14.80


Total lens
203.11
203.11
203.11


length


BF
40.01
40.01
40.01


d12
40.75
20.66
5.78


d15
0.47
10.45
9.01


d17
0.28
10.39
26.71


d23
15.77
13.70
7.09


d25
0.38
2.46
9.06


Entrance pupil
29.39
30.00
32.20


position


Exit pupil position
−109.44
−96.61
−73.75


Front principal
38.72
43.35
51.70


point position


Rear principal
30.01
25.01
15.01


point position










Zoom lens unit data
















Front
Rear





Lens
principal
principal



First
Focal
structure
point
point


Unit
surface
length
length
position
position





1
1
−20.00
58.25
13.07
−36.21


21
13
85.34
8.14
1.65
−3.54


22
16
60.73
6.30
2.23
−2.23


3
18
−28.94
9.71
5.01
−1.60


4
24
79.38
2.90
2.34
0.42


5
26
59.14
20.15
2.30
−13.32
















TABLE 1





Values of respective conditional expressions in Numerical Embodiments
















Conditional
Embodiment













Expression
1
2
3
4
5
6


















f1
−43.5
−33.2
−47.91
−32.12
−30.26
−65



f11
−81.84
−59.24
−71.91
−51.11
−24.47




f12p
—
—
—
—
234.79
—



f12n
−120.26
−111.81
−199.65
−118.05
—
—



f21
89.3
103
—
90.9
94.2
−115.33



f22
88.1
66
—
58.6
76.7
38.59



f3
−33.91
−33.8
−17.49
−21.41
−33.52
−18



f4
57.2
72
28.63
39.5
66.1
34.79



fw
18.5
15.5
18
16.5
13
17



|m2|
56.74
45.93
28.65
32.28
46.59
37.2



|m4|
16.98
11.34
15.12
6.94
11.83
4.58



β2_w
−0.533
−0.555
−0.664
−0.611
−0.556
−0.34



β2_t
−1.545
−1.328
−1.149
−1.29
−1.305
−0.768



β21_w
−2.28
−10.388
—
−30.8
−3.605
0.56



β21_t
5.086
2.86
—
3.101
4.607
0.57



β22_w
0.235
0.054
—
0.02
0.152
−0.6



β22_t
−0.307
−0.467
—
−0.419
−0.275
−1.339



θ2p
0.5402
0.5352
0.5426
0.5441
0.5352
0.5441



ν2p
60.67
64.14
60.29
63.33
64.14
63.33



θ2n
0.6017
0.6017
0.6135
0.6017
0.6017
0.6122



ν2n
29.84
29.84
26.52
29.84
29.84
24.8


(1)
f1/f3
1.28
0.98
2.74
1.5
0.9
3.61


(2)
|m2|/|m4|
3.34
4.05
1.89
4.65
3.94
8.12


(3)
β2_t/β2_w
2.9
2.39
1.73
2.11
2.35
2.26


(4)
f1/fw
−2.35
−2.14
−2.66
−1.95
−2.33
−3.82


(5)
|β2_w|
0.53
0.56
0.66
0.61
0.56
0.34


(6)
f11/f12p
—
—
—
—
−0.1
—


(7)
f11/f12n
0.68
0.53
0.36
0.43
—
—


(8)
(θ2p − θ2n)/
−1.99E−03
−1.94E−03
−2.1E−03
−1.72E−03
−1.94E−03
−1.77E−03



(ν2p − ν2n)


(9)
f1/f21
−0.49
−0.32
—
−0.35
−0.32
0.56


(10) 
f1/f4
−0.76
−0.46
−1.67
−0.81
−0.46
−1.87


(11) 
f21/f22
1.01
1.56
—
1.55
1.23
−2.99













Conditional
Embodiment














Expression
7
8
9
10
11




















f1
−30.13
−27.42
−28.62
−20
−20




f11
−53.16
−22.78
−52.71
−16.73
−17.5




f12p
—
217.89
—
270.71
287.5




f12n
−96.46
—
−92.31
—
—




f21
95.8
65.39
108.4
119.29
85.3




f22
58.99
52.4
51.76
60.2
60.7




f3
−25.4
−18.7
−18.92
−29.98
−28.9




f4
41.05
59.47
24.05
68.52
79.4




fw
15.5
15
16
9.5
10




|m2|
34.47
19.8
34.73
36.57
34.97




|m4|
11.86
12.38
3.61
6.18
8.68




β2_w
−0.639
−0.642
−0.615
−0.645
−0.567




β2_t
−1.526
−1.105
−1.492
−1.476
−1.169




β21_w
38.68
−6.28
6.33
6.82
−6.433




β21_t
2.59
6.96
2.09
2.21
3.932




β22_w
−0.017
0.1
−0.097
−0.094
0.088




β22_t
−0.593
−0.153
−0.718
−0.655
−0.297




θ2p
0.5684
0.5442
0.5633
0.563
0.563




ν2p
44.87
67.74
44.3
48.84
48.84




θ2n
0.6161
0.6133
0.6161
0.6133
0.6133




ν2n
25.42
25.46
25.42
25.46
25.46



(1)
f1/f3
1.19
1.47
1.51
0.67
0.69



(2)
|m2|/|m4|
2.91
1.6
9.62
5.92
4.03



(3)
β2_t/β2_w
2.39
1.72
2.43
2.29
2.06



(4)
f1/fw
−1.94
−1.83
−1.79
−2.11
−2.00



(5)
|β2_w|
0.64
0.64
0.61
0.64
0.57



(6)
f11/f12p
—
−0.1
—
−0.06
−0.06



(7)
f11/f12n
0.55
—
0.57
—
—



(8)
(θ2p − θ2n)/
−2.45E−03
−1.63E−03
−2.8E−03
−2.15E−03
−2.15e−03




(ν2p − ν2n)



(9)
f1/f21
−0.31
−0.42
−0.26
−0.17
−0.23



(10) 
f1/f4
−0.73
−0.46
−1.19
−0.29
−0.25



(11) 
f21/f22
1.62
1.25
2.09
1.98
1.41










While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2015-206169, filed Oct. 20, 2015 and Japanese Patent Application No. 2015-206170, filed Oct. 20, 2015 which are hereby incorporated by reference herein in their entirety.

## Claims

1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a negative refractive power and being not moved for zooming;
a second lens unit being moved during zooming, and having a positive refractive power;
a third lens unit including an aperture stop, being not moved for zooming, and having a negative refractive power;
a fourth lens unit being moved during zooming; and
a fifth lens unit being not moved for zooming,
wherein at least three of a lens sub unit are included in the second lens unit and the fourth lens unit, and are moved in an optical axis direction during zooming,
wherein the following expressions are satisfied:


0.6<f1/f3<4.0; and



1.4<|m2|/|m4|<50.0,



where f1 and f3 respectively represent focal lengths of the first lens unit and the third lens unit, and m2 and m4 respectively represent a movement amount of one of the lens sub unit that is moved by a largest amount in the second lens unit during zooming from a wide angle end to a telephoto end and a movement amount of one of the lens sub unit that is moved by a largest amount in the fourth lens unit during zooming from the wide angle end to the telephoto end.

2. A zoom lens according to claim 1, wherein the following expression is satisfied:


1.5<β2_t/β2_w<4.0,


where β2_w and β2_t respectively represent lateral magnifications of the second lens unit at the wide angle end and the telephoto end.

3. A zoom lens according to claim 1, wherein the following expression is satisfied:


−5.0<f1/fw<−1.5,


where fw represents a focal length of the zoom lens at the wide angle end in a state of focusing at infinity.

4. A zoom lens according to claim 1, wherein the following expression is satisfied:


|β2_w|<1.0,


where |β2_w| represents an absolute value of a lateral magnification of the second lens unit at the wide angle end.

5. A zoom lens according to claim 1, wherein the third lens unit comprises at least two lenses having negative refractive powers.

6. A zoom lens according to claim 1, wherein a lens closest to the object side in the first lens unit comprises a lens having a negative refractive power.

7. A zoom lens according to claim 1, wherein the first lens unit comprises a lens sub unit (L11) having a negative refractive power and being not moved for focusing, and a lens sub unit (L12) being moved during focusing.

8. A zoom lens according to claim 7, wherein the lens sub unit (L12) has a positive refractive power, and the following expression is satisfied:


−0.15<f11/f12p<−0.04,


where f11 represents a focal length of the lens sub unit (L11), and f12p represents a focal length of the lens sub unit (L12).

9. A zoom lens according to claim 7, wherein the lens sub unit (L12) has a negative refractive power, and the following expression is satisfied:


0.3<f11/f12n<0.8,


where f11 represents a focal length of the lens sub unit (L11), and f12n represents a focal length of the lens sub unit (L12).

10. A zoom lens according to claim 1, wherein the second lens unit comprises at least one cemented lens formed of one convex lens and one concave lens, and satisfies the following expression:


−3.00×10−3<(θ2p−θ2n)/(ν2p−ν2n)<−1.5×10−3,


where ν2p represents an Abbe number of the convex lens, θ2p represents a partial dispersion ratio of the convex lens, ν2n represents an Abbe number of the concave lens, and θ2n represents a partial dispersion ratio of the concave lens, an Abbe number νd and a partial dispersion ratio θgF are defined as follows:


νd=(Nd−1)/(NF−NC); and



θgF=(Ng−NF)/(NF−NC),


where Ng, NF, Nd, and NC respectively represent refractive indices for a g-line, a F-line, a d-line, and a C-line of Fraunhofer lines.

11. A zoom lens according to claim 1, wherein the second lens unit and the fourth lens unit comprise a lens having at least one aspherical surface.

12. A zoom lens according to claim 1, wherein the second lens unit comprises a lens sub unit (L21) and a lens sub unit (L22) which are moved along mutually different loci during zooming.

13. A zoom lens according to claim 12, wherein the following expression is satisfied:


−0.60<f1/f21<−0.15,


where f21 represents a focal length of the lens sub unit (L21).

14. A zoom lens according to claim 1, wherein the following expression is satisfied:


−1.00<f1/f4<−0.15,


where f4 represents a focal length of the fourth lens unit.

15. A zoom lens according to claim 12, wherein the following expression is satisfied:


0.8<f21/f22<1.8,


where f21 represents a focal length of the lens sub unit (L21), and f22 represents a focal length of the lens sub unit (L22).

16. A zoom lens according to claim 12, wherein the lens sub unit (L21), the lens sub unit (L22), and the fourth lens unit are configured to move during zooming.

17. An image pickup apparatus, comprising:
a zoom lens; and
an image pickup element configured to receive light of an image formed by the zoom lens,
the zoom lens comprising in order from an object side to an image side:
a first lens unit having a negative refractive power and being not moved for zooming;
a second lens unit being moved during zooming, and having a positive refractive power;
a third lens unit including an aperture stop, being not moved for zooming, and having a negative refractive power;
a fourth lens unit being moved during zooming; and
a fifth lens unit being not moved for zooming,
wherein at least three of a lens sub unit are included in the second lens unit and the fourth lens unit, and are moved in an optical axis direction during zooming,
wherein the following expressions are satisfied:


0.6<f1/f3<4.0; and



1.4<|m2|/|m41<50.0,


where f1 and f3 respectively represent focal lengths of the first lens unit and the third lens unit, and m2 and m4 respectively represent a movement amount of one of the lens sub unit that is moved by a largest amount in the second lens unit during zooming from a wide angle end to a telephoto end and a movement amount of one of the lens sub unit that is moved by a largest amount in the fourth lens unit during zooming from the wide angle end to the telephoto end.