JP2021196572A - Zoom lens and imaging device - Google Patents

Abstract

To provide a small-sized zoom lens and imaging device for cameras whose miniaturization is progressing.SOLUTION: A zoom lens comprises, in order from an object side, a first lens group having negative refractive power, an intermediate group comprising one or more lens groups and having positive refractive power as a whole, a lens group LN having negative refractive power, and a final lens group having negative refractive power, where an interval between adjacent lens group changes when variably changing the power or focusing, and where the zoom lens satisfies a prescribed conditional expression. An imaging device includes the zoom lens.SELECTED DRAWING: Figure 1

Description

The present invention relates to a zoom lens and an image pickup device.

In image pickup devices using solid-state image sensors such as digital still cameras and digital video cameras, the number of pixels in solid-state image sensors has been increasing in recent years, and as a result, the optical system is also required to have higher performance than before. There is. Further, with the miniaturization of the image pickup apparatus, a compact zoom lens is also required for the optical system.

Patent Document 1 describes a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, and a third lens group having a negative refractive power in order from the object side. A variable magnification optical system composed of 4 lens groups, a 5th lens group having a negative refractive power, a 1st lens group having a negative refractive power in order from the object side, and a 2nd lens group having a positive refractive power. , A variable magnification optical system composed of a third lens group having a negative refractive power and a fourth lens group having a negative refractive power is disclosed.

Japanese Unexamined Patent Publication No. 2019-008031

In the zoom lenses described in Examples 1, 4 and 6 of Patent Document 1, since the refractive power of the lens group having a positive refractive power is weak, the overall length cannot be shortened and the miniaturization is insufficient. There's a problem.

Therefore, an object of the present invention is to provide a compact zoom lens.

In order to solve the above problems, the zoom lens according to the present invention includes a first lens group having a negative refractive power and an intermediate group consisting of one or more lens groups having a positive refractive power as a whole, in order from the object side. It is composed of a lens group LN having a negative refractive power and a final lens group having a negative refractive power.
When scaling or focusing, the distance between adjacent lens groups changes,
It is characterized by satisfying the following conditional expression.
-1.20 ≤ f1 / fpt ≤ -0.05 ... (1)
0.05 ≤ fpMax / fw ≤ 1.25 ... (2)
However,
f1: Focal length of the first lens group fpt: Focal length of the intermediate group at infinity focusing at the telephoto end fpMax: Of the lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Focal length fw: Focal length at infinity focusing at the wide-angle end of the zoom lens

Further, in order to solve the above problems, the image pickup apparatus according to the present invention is characterized by including the zoom lens and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal. ..

According to the present invention, it is possible to provide a small zoom lens and an image pickup device.

It is sectional drawing of the zoom lens of Example 1. FIG. It is an aberration diagram at the wide-angle end of the zoom lens of Example 1. FIG. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 1. FIG. It is an aberration diagram at the telephoto end of the zoom lens of Example 1. FIG. It is sectional drawing of the zoom lens of Example 2. FIG. It is an aberration diagram at the wide-angle end of the zoom lens of Example 2. FIG. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 2. FIG. It is an aberration diagram at the telephoto end of the zoom lens of Example 2. FIG. It is sectional drawing of the zoom lens of Example 3. FIG. It is an aberration diagram at the wide-angle end of the zoom lens of Example 3. FIG. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 3. FIG. It is an aberration diagram at the telephoto end of the zoom lens of Example 3. FIG. It is sectional drawing of the zoom lens of Example 4. FIG. It is an aberration diagram at the wide-angle end of the zoom lens of Example 4. FIG. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 4. FIG. It is an aberration diagram at the telephoto end of the zoom lens of Example 4. FIG. It is sectional drawing of the zoom lens of Example 5. FIG. It is an aberration diagram at the wide-angle end of the zoom lens of Example 5. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 5. It is an aberration diagram at the telephoto end of the zoom lens of Example 5. It is sectional drawing of the zoom lens of Example 6. It is an aberration diagram at the wide-angle end of the zoom lens of Example 6. It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 6. It is an aberration diagram at the telephoto end of the zoom lens of Example 6. It is a figure which shows typically an example of the structure of the image pickup apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the zoom lens and the image pickup apparatus according to the present invention will be described. However, the zoom lens and the image pickup apparatus described below are one aspect of the zoom lens and the image pickup apparatus according to the present invention, and the zoom lens and the image pickup apparatus according to the present invention are not limited to the following aspects.

1. 1. Zoom lens 1-1. Optical configuration The zoom lens is composed of a first lens group having a negative refractive power, an intermediate group consisting of one or more lens groups having a positive refractive power as a whole, and a lens having a negative refractive power in order from the object side. It is composed of a group LN and a final lens group having a negative refractive power. By adopting such an optical configuration of the telephoto type refractive power arrangement, the image side of the first lens group can have a power arrangement with a strong telephoto tendency, and the combined focal length from the intermediate group to the final lens group can be obtained. The length on the optical axis from the intermediate group to the final lens group can be shortened as compared with the above.

(1) First lens group The first lens group is a lens group having a negative refractive power, and the specific configuration thereof is not particularly limited as long as it has at least one lens having a negative refractive power. .. Further, it is preferable that the first lens group has at least one lens L1p having a positive refractive power. It is preferable to have at least one lens having a negative refractive power together with at least one positive lens L1p because it is easy to suppress chromatic aberration and achieve good optical performance. Further, in the first lens group, a lens having a negative refractive power, a lens having a negative refractive power, and a lens having a positive refractive power in order from the object side suppresses chromatic aberration and facilitates miniaturization. More preferred.

Here, the lens group is composed of one lens or a plurality of lenses adjacent to each other, and moves by the same amount of movement along the optical axis along the optical axis at the time of scaling or focusing. When one lens group is composed of a plurality of lenses, the distance on the optical axis between the lenses included in the one lens group shall not change at the time of scaling or focusing. Further, the distance on the optical axis between adjacent lens groups shall change at the time of scaling or focusing.

(2) Intermediate group The intermediate group is a group having a positive refractive power as a whole, and its specific configuration is not particularly limited as long as it has one or more lenses having a positive refractive power. The intermediate group may have two or more lens groups having a positive refractive power, or may have one or more lens groups having a positive refractive power and one or more lens groups having a negative refractive power. Is also good. Further, in the intermediate group, it is preferable to have a junction lens of a lens having a positive refractive power and a lens having a negative refractive power because it is easy to suppress chromatic aberration and suppress the sensitivity of each lens. Further, in the intermediate group, the lens group having the strongest refractive power among the lens groups preferably has at least one positive refractive power and a lens LpMp having a positive refractive power. Further, it is more preferable that the lens on the image side most in the intermediate group has a convex shape on the image side. By having this configuration, the curvature of field can be satisfactorily corrected, and it becomes easy to reduce the size.

(3) Aperture diaphragm The arrangement of the aperture diaphragm is not particularly limited in the zoom lens. However, the aperture diaphragm referred to here means an aperture diaphragm that defines the luminous flux diameter of the zoom lens, that is, an aperture diaphragm that defines the Fno of the zoom lens. However, it is preferable to arrange the aperture diaphragm on the image side of the first lens group, particularly in the middle group, in order to reduce the size of the diaphragm unit. Further, when the intermediate group includes a lens group having a negative refractive power, it is preferable that the aperture diaphragm is arranged on the object side of the lens group having the negative refractive power. In order to cancel the negative distortion and the negative curvature of field that occur in the first lens group, aberrations in the same direction may be generated before and after the aperture diaphragm is sandwiched. Therefore, by arranging the aperture diaphragm on the image side of the first lens group and on the object side of the lens group having a negative refractive power in the middle group, aberrations can be efficiently canceled before and after the aperture diaphragm, and optics can be obtained. It is preferable to obtain a high-performance zoom lens.

(4) Lens group LN
The lens group LN is a lens group having a negative refractive power, and the specific configuration thereof is not particularly limited as long as it has at least one lens having a negative refractive power. Further, in the lens group LN, it is preferable to have at least one lens having a positive refractive power because it is easy to suppress chromatic aberration and achieve good optical performance. Further, in the lens group LN, the shape of the lens having a negative refractive power is more preferably concave on the image side, and it becomes easy to correct the curvature of field and reduce the size. Further, it is more preferable to have a biconcave shape, which facilitates miniaturization.

(5) Final lens group The final lens group is a lens group having a negative refractive power, and the specific configuration thereof is not particularly limited as long as it has at least one lens having a negative refractive power. Further, in the final lens group, it is preferable to have at least one lens having a positive refractive power because it is easy to suppress chromatic aberration and achieve good optical performance. Further, in the final lens group, it is preferable to have a lens LnL having a negative refractive power on the most image side, because it is easy to suppress distortion and coma and achieve good optical performance.

1-2. Operation (1) Magnification The zoom lens adopts the above configuration, and at the time of magnification change, the distance on the optical axis between the intermediate group consisting of the first lens group and one or more lens groups, the lens group LN, and the final lens group. Is multiplied by changing. By moving each lens group in this way, it becomes easy to obtain good optical performance over the entire range of magnification without forcibly increasing the power of each lens group.

In addition, by adopting the above configuration and making the final lens group and at least one or more other lens groups the same locus at the time of scaling, it is possible to simplify the mechanical structure and reduce the size of the entire zoom lens. It becomes easy to plan.

(2) Focusing In the zoom lens, it is preferable that the lens group LN moves toward the object on the optical axis when focusing from infinity to a short distance. Since the lens group LN is arranged on the image side of the intermediate group and the fluctuation of the incident angle of the light beam is small, it is easy to suppress the fluctuation of the angle of view at the time of focusing.

1-3. Conditional expression It is desirable that the zoom lens adopts the above-mentioned configuration and satisfies at least one conditional expression described below.

1-3-1. Conditional expression (1)
-1.20 ≤ f1 / fpt ≤ -0.05 ... (1)
However,
f1: Focal length of the first lens group fpt: Focal length of the middle group at infinity focusing at the telephoto end

The conditional expression (1) is a conditional expression that defines the ratio between the focal length of the first lens group and the combined focal length of the intermediate group at the telephoto end. By satisfying the conditional expression (1), the angle of view can be widened at the wide-angle end, and aberration fluctuations at the time of scaling can be suppressed. That is, it becomes easy to realize a zoom lens having a wide angle of view at the wide-angle end and high optical performance.

On the other hand, when the value of the conditional expression (1) becomes less than the lower limit value, the refractive power of the first lens group becomes too weak with respect to the refractive power of the intermediate group, or the refractive power of the first lens group becomes too weak. On the other hand, the refractive power of the intermediate group may become too strong. When the refractive power of the first lens group becomes relatively weak, it is necessary to arrange a lens having a large lens diameter on the object side among the lenses constituting the first lens group in order to achieve a wide angle of view at the wide-angle end. This makes it difficult to reduce the size in the radial direction.

Further, when the refractive power of the intermediate group becomes relatively weak, it is necessary to increase the optical total length of the zoom lens. From these facts, when the value of the conditional expression (1) is less than the lower limit value, it becomes difficult to realize a zoom lens which is small and has high optical performance, which is not preferable. On the other hand, when the value of the conditional expression (1) exceeds the upper limit value, the refractive power of the first lens group becomes too strong with respect to the refractive power of the intermediate group. In this case, it becomes difficult to correct coma aberration and distortion, and it becomes difficult to realize a zoom lens having high optical performance.

In order to obtain the above effect, the lower limit of the conditional expression (1) is preferably -1.15, more preferably -1.10, and even more preferably -1.05. The upper limit of the conditional expression (1) is preferably −0.10, more preferably −0.15, and even more preferably −0.20. When adopting these preferable lower limit values or upper limit values, the inequality sign (≦) with an equal sign may be replaced with an inequality sign (<) in the conditional expression (1). The same applies to other conditional expressions in principle.

1-3-2. Conditional expression (2)
0.05 ≤ fpMax / fw ≤ 1.25 ... (2)
However,
fpMax: Focal length of the lens group with the strongest positive refractive power among the lens groups included in the intermediate group ww: Focal length at infinity focusing at the wide-angle end of the zoom lens

The above conditional expression (2) is a conditional expression that defines the ratio of the focal length of the lens group having the strongest positive refractive power among the lens groups included in the intermediate group to the focal length of the zoom lens at the wide-angle end. By satisfying the conditional expression (2), it becomes possible to make the power arrangement stronger in the telephoto tendency, and it becomes easy to shorten the optical overall length.

On the other hand, when the value of the conditional expression (2) becomes less than the lower limit value, the refractive power of the lens group having the strongest positive refractive power among the lens groups included in the intermediate group becomes too strong, so that spherical aberration occurs. It becomes difficult to correct, which is not preferable. On the other hand, if the value of the conditional expression (2) exceeds the upper limit value, the total length becomes long and it becomes difficult to reduce the size of the entire zoom lens.

In order to obtain the above effect, the lower limit of the conditional expression (2) is preferably 0.10, more preferably 0.15, and even more preferably 0.25. The upper limit of the conditional expression (2) is preferably 1.25, more preferably 1.20, further preferably 1.15, and even more preferably 1.05.

1-3-3. Conditional expression (3)
-3.00 ≤ f1 / fw ≤ -1.00 ... (3)
However,
f1: Focal length of the first lens group ww: Focal length at infinity focusing at the wide-angle end of the zoom lens

The above conditional expression (3) is a conditional expression that defines the ratio of the focal length of the first lens group to the focal length at the wide-angle end of the zoom lens at infinity focusing. By satisfying the conditional expression (3), the angle of view can be widened in the wide-angle end state, and it becomes easy to suppress the aberration fluctuation at the time of scaling. That is, it becomes easy to realize a zoom lens having a wide angle of view at the wide-angle end, a small size, and high optical performance.

On the other hand, when the value of the conditional expression (3) becomes less than the lower limit value, the lens diameter is large especially on the object side among the lenses constituting the first lens group in order to achieve wide angle of view at the wide angle end. It is necessary to arrange the lens, which makes it difficult to reduce the size in the radial direction. On the other hand, when the value of the conditional expression (3) exceeds the upper limit value, the refractive power of the first lens group becomes too strong, which makes it difficult to correct coma aberration and distortion, and miniaturization of a zoom lens having high optical performance. Becomes difficult.

In order to obtain the above effect, the lower limit of the conditional expression (3) is preferably -2.90, more preferably -2.80, and even more preferably -2.70. The upper limit of the conditional expression (3) is preferably -1.10, more preferably -1.15, and even more preferably -1.20.

1-3-4. Conditional expression (4)
-1.50 ≤ fn1 / ft ≤ -0.05 ... (4)
However,
fn1: Focal length of lens group LN ft: Focal length at infinity focusing at the telephoto end of the zoom lens

The above conditional expression (4) is a conditional expression that defines the ratio of the focal length of the lens group LN to the focal length at the telephoto end of the zoom lens at infinity focusing. By satisfying the conditional expression (4), it becomes possible to arrange the power with a strong tendency for telephoto, and it becomes easy to shorten the optical overall length.

On the other hand, if the value of the conditional expression (4) is less than the lower limit value, the total length becomes long and miniaturization becomes difficult. On the other hand, when the value of the conditional expression (4) exceeds the upper limit value, the refractive power of the lens group LN becomes too strong, and it becomes difficult to correct the distortion aberration and the coma aberration.

In order to obtain the above effect, the lower limit of the conditional expression (4) is preferably −1.45, more preferably −1.35. The upper limit of the conditional expression (4) is preferably −0.10, more preferably −0.15, and even more preferably −0.20.

1-3-5. Conditional expression (5)
0.05 ≤ frt / ft ≤ 1.50 ... (5)
However,
frt: Composite focal length from the intermediate group to the final lens group at the telephoto end at infinity ft: Focal length at the telephoto end of the zoom lens at infinity

The above conditional expression (5) is a conditional expression that defines the combined focal length from the intermediate group to the final lens group at the telephoto end at infinity focus and the focal length at the telephoto end of the zoom lens at infinity focus. .. By satisfying the conditional expression (5), it becomes easy to achieve both miniaturization of the zoom lens and optical performance.

On the other hand, when the value of the conditional expression (5) is less than the lower limit value, it becomes difficult to correct distortion, coma, and spherical aberration. On the other hand, when the value of the conditional expression (5) exceeds the upper limit value, the lens on the object side in the first lens group has a large diameter, and it becomes difficult to reduce the size.

In order to obtain the above effect, the lower limit of the conditional expression (5) is preferably 0.10, more preferably 0.15, and even more preferably 0.20. The upper limit of the conditional expression (5) is preferably 1.45, more preferably 1.40, and even more preferably 1.35.

1-3-6. Conditional expression (6)
-1.50 ≤ fn12 / ft ≤ -0.05 ... (6)
However,
fn12: Synthetic focal length from the lens group LN at infinity focusing at the telephoto end to the final lens group ft: Focal length at infinity focusing at the telephoto end of the zoom lens

The above conditional equation (6) defines the ratio of the combined focal length from the lens group LN at the telephoto end to the final lens group and the focal length of the zoom lens at the telephoto end when the zoom lens is in focus. It is a conditional expression of. By satisfying the conditional expression, it becomes possible to arrange the power with a strong tendency for telephoto, and it becomes easy to shorten the optical overall length.

On the other hand, when the value of the conditional expression (6) is less than the lower limit value, the total optical length becomes long and it becomes difficult to reduce the size. On the other hand, when the value of the conditional expression (6) exceeds the upper limit value, the refractive power of the final lens group becomes too strong, and it becomes difficult to correct the distortion aberration and the coma aberration.

In order to obtain the above effect, the lower limit of the conditional expression (6) is preferably -1.40, more preferably -1.35. The upper limit of the conditional expression (6) is preferably −0.10, more preferably −0.15, and even more preferably −0.20.

1-3-7. Conditional expression (7)
1.00 ≤ βn1 ≤ 5.00 ... (7)
However,
βn1: Horizontal magnification of the lens group LN at infinity focusing at the wide-angle end

The above conditional expression (7) is a conditional expression for defining the lateral magnification of the lens group LN at the time of infinity focusing at the wide-angle end. By satisfying the conditional expression (7), it becomes easy to improve the optical performance in the entire zoom range, and it becomes easy to shorten the optical overall length.

On the other hand, when the value of the conditional expression (7) is less than the lower limit value, the amount of movement of the lens group LN at the scaling from the wide-angle end to the telephoto end becomes too large, so that the total length becomes long and the size is reduced. Becomes difficult. On the other hand, if the value of the conditional expression (7) exceeds the upper limit value, the lateral magnification of the lens group LN becomes too high, and it becomes difficult to correct the distortion and the curvature of field.

In order to obtain the above effect, the lower limit of the conditional expression (7) is preferably 1.10, more preferably 1.20. The upper limit of the conditional expression (7) is preferably 4.90, more preferably 4.80, and even more preferably 4.70.

1-3-8. Conditional expression (8)
1.00 ≤ βn12 ≤ 5.00 ... (8)
However,
βn12: Combined lateral magnification from the lens group LN to the final lens group at infinity focusing at the wide-angle end

The above conditional expression (8) is a conditional expression for defining the combined lateral magnification from the lens group LN to the final lens group at the time of infinity focusing at the wide-angle end. By satisfying the conditional expression (8), it becomes easy to improve the optical performance in the entire zoom range, and it becomes easy to shorten the optical overall length.

On the other hand, if the value of the conditional expression (8) is less than the lower limit, the amount of movement of the lens group LN at the scaling from the wide-angle end to the telephoto end becomes too large, so that the total length becomes long and the size is reduced. Becomes difficult. On the other hand, if the value of the conditional expression (8) exceeds the upper limit value, the lateral magnification of the lens group LN becomes too high, and it becomes difficult to correct distortion and curvature of field.

In order to obtain the above effect, the lower limit of the conditional expression (8) is preferably 1.10, more preferably 1.20. The upper limit of the conditional expression (8) is preferably 4.90, more preferably 4.80, and even more preferably 4.70.

1-3-9. Conditional expression (9)
1.0 ≦ | {1- (βn1 × βn1)} × (βn2 × βn2) | ≦ 15.0 ... (9)
However,
βn1: Lateral magnification of lens group LN at infinity focus at wide-angle end βn2: Lateral magnification of final lens group at infinity focus at wide-angle end

The above conditional equation (9) is an equation for defining the absolute value of the focus sensitivity of the lens group LN that moves on the optical axis at the time of focusing, that is, the amount of image plane movement when the lens group LN moves by a unit amount. ..
By satisfying the conditional expression (9), it is possible to shorten the amount of movement of the focus at the time of focusing from infinity to a close distance, and it becomes easy to shorten the total optical length.

On the other hand, when the value of the conditional expression (9) is less than the lower limit value, the amount of movement during focusing from infinity to a close distance becomes large, and it becomes difficult to reduce the total optical length. On the other hand, if the value of the conditional expression (9) exceeds the upper limit value, the amount of movement of the lens group LN for correcting the positional deviation of the focus position becomes too small, which makes high-precision control difficult.

In order to obtain the above effect, the lower limit of the conditional expression (9) is preferably 1.20, more preferably 1.30. The upper limit of the conditional expression (9) is preferably 14.0, more preferably 13.0, and even more preferably 12.0.

1-3-10. Conditional expression (10)
1.00 ≤ ｜ CrG1r / fw ｜ ・ ・ ・ ・ ・ (10)
However,
CrG1r: Radius of curvature of the surface on the most image side of the first lens group fw: Focal length at infinity focusing at the wide-angle end of the zoom lens

The above conditional expression (10) is a conditional expression for defining the ratio of the radius of curvature of the surface of the first lens group on the image side to the focal length at the wide-angle end of the zoom lens at infinity focusing. By satisfying the conditional equation (10), it becomes easy to correct spherical aberration and curvature of field, and to achieve miniaturization while achieving high performance.

On the other hand, when the value of the conditional expression (10) is less than the lower limit value, the curvature of field becomes overcorrected, and the lens on the object side in the first lens group has a large diameter, which makes it difficult to reduce the size.

In order to obtain the above effect, the lower limit of the conditional expression (10) is preferably 1.10, more preferably 1.20, and even more preferably 1.30.

1-3-11. Conditional expression (11)
0.65 ≤ (fw x tanω) / BFw ≤ 2.30 ... (11)
However,
fw: Focal length at infinity focusing at the wide-angle end of the zoom lens ω: Half angle of view at infinity focusing at the wide-angle end of the zoom lens BFw: Infinity focusing at the wide-angle end of the zoom lens Air equivalent length on the optical axis from the surface on the image side to the image surface

The above conditional expression (11) is a conditional expression for defining the half angle of view at the wide-angle end of the zoom lens at infinity focusing and the air conversion length on the optical axis from the surface closest to the image side to the image surface. .. By satisfying the conditional expression (11), it becomes possible to realize high performance of the optical performance in the entire zoom range, and it becomes easy to shorten the optical overall length.

On the other hand, when the value of the conditional expression (11) is less than the lower limit value, it is necessary to increase the angle of incidence of the off-axis light rays on the image plane. Therefore, it is necessary to reduce the focal length of the final lens group, which makes it difficult to correct coma aberration and distortion. Alternatively, it becomes necessary to increase the lens diameter of the final lens group, which makes it difficult to reduce the size. On the other hand, when the value of the conditional expression (11) exceeds the upper limit value, the total length becomes long and miniaturization becomes difficult.

In order to obtain the above effect, the lower limit of the conditional expression (11) is preferably 0.70, more preferably 0.75, further preferably 0.85, and even more preferably 0.90. .. The upper limit of the conditional expression (11) is more preferably 2.10, further preferably 2.00, still more preferably 1.90, and even more preferably 1.80. ..

1-3-12. Conditional expression (12)
45.0 ≤ νdLpMp ≤ 98.0 ... (12)
However,
νdLpMp: Abbe number on the d-line of the lens LpMp contained in the lens group LpMax having the strongest positive refractive power in the intermediate group.

The above conditional equation (12) is an equation for defining the Abbe number on the d-line of the lens LpMp included in the lens group LpMax having the strongest positive refractive power in the intermediate group. By satisfying the conditional equation (12), it becomes easy to achieve both axial chromatic aberration and spherical aberration.

On the other hand, when the value of the conditional expression (12) is less than the lower limit value, it becomes difficult to correct the axial chromatic aberration. On the other hand, if the value of the conditional expression (12) exceeds the upper limit value, the lens becomes expensive, which is not preferable in terms of cost reduction.

In order to obtain the above effect, the lower limit of the conditional expression (12) is preferably 50.0, more preferably 60.0. The upper limit of the conditional expression (12) is preferably 95.0, more preferably 90.0, and even more preferably 85.0.

1-3-13. Conditional expression (13)
20.0 ≤ νdL1p ≤ 50.0 ... (13)
However,
νdL1p: Abbe number on the d line of the lens L1p

The conditional expression (13) is an expression for defining the Abbe number in the d line of at least one lens L1p having a positive refractive power included in the first lens group. By satisfying the conditional expression (13), it is easy to reduce the cost while ensuring a good image plane property.

On the other hand, when the value of the conditional expression (13) is less than the lower limit value, it becomes difficult to reduce the cost because the low-dispersion glass is expensive. On the other hand, when the value of the conditional expression (13) exceeds the upper limit value, the highly dispersed glass is expensive, and it becomes difficult to reduce the cost.

In order to obtain the above effect, the lower limit of the conditional expression (13) is preferably 23.0, more preferably 26.0, and even more preferably 29.0. The upper limit of the conditional expression (13) is preferably 47.0, more preferably 44.0, and even more preferably 41.0.

1-3-14. Conditional expression (14)
1.70 ≤ NdL1p ≤ 2.20 ... (14)
However,
NdL1p: Refractive index of the lens L1p on the d line

The conditional expression (14) is an expression for defining the refractive index of the lens L1p, which is included in the first lens group and has a positive refractive power, on the d line. By satisfying the conditional expression (14), it is easy to reduce the cost while ensuring a good image plane property.

On the other hand, when the value of the conditional expression (14) is less than the lower limit value, it becomes difficult to reduce the cost because the low refractive index glass is expensive. On the other hand, when the value of the conditional expression (14) exceeds the upper limit value, the high refractive index glass is expensive, and it becomes difficult to reduce the cost.

In order to obtain the above effect, the lower limit of the conditional expression (14) is preferably 1.75, more preferably 1.80, and even more preferably 1.85. The upper limit of the conditional expression (14) is preferably 2.15, more preferably 2.10, and even more preferably 2.05.

1-3-15. Conditional expression (15)
-3.00 ≤ fLnL / ft ≤ -0.05 ... (15)
However,
fLnL: Focal length of lens LnL ft: Focal length at infinity focusing at the telephoto end of the zoom lens

The above conditional expression (15) is a conditional expression for defining the ratio of the focal length of the lens LnL arranged on the image side of the final lens group to the focal length at the telephoto end of the zoom lens at infinity focusing. .. By satisfying the conditional expression (15), it becomes easy to realize a compact zoom lens having a short back focus.

On the other hand, if the value of the conditional expression (15) is less than the lower limit value, the height of the peripheral light rays passing through the lens LnL from the optical axis becomes high, which makes the lens larger in diameter and difficult to miniaturize. Become. On the other hand, when the value of the conditional expression (15) exceeds the upper limit value, the refractive power of the lens LnL becomes too strong, and it becomes difficult to correct the distortion aberration and the coma aberration.

In order to obtain the above effect, the lower limit of the conditional expression (15) is preferably -2.90, more preferably -2.80, and even more preferably -2.70. The upper limit of the conditional expression (15) is preferably −0.10, more preferably −0.15, and even more preferably −0.20.

1-3-16. Conditional expression (16)
| BFt-BFw | / TLw ≤ 0.30 ... (16)
However,
BFw: Air equivalent length on the optical axis from the most image-side surface to the image plane at the wide-angle end of the zoom lens at infinity BFt: Most image-side at infinity-focused at the telephoto end of the zoom lens Air equivalent length on the optical axis from the plane to the image plane TLw: Optical total length at infinity focusing at the wide-angle end of the zoom lens

The conditional expression (16) is a conditional expression for defining the amount of movement of the final lens group toward the object when scaling from the wide-angle end to the telephoto end. Here, the optical total length indicates the total length on the optical axis from the lens on the object side to the image plane among the lenses constituting the zoom lens, and is a numerical value including the cover glass and the IR cut filter between them. By satisfying the conditional expression (16), the refractive power of the final lens group is appropriate, and the amount of movement at the time of scaling is within an appropriate range. Therefore, it becomes easy to shorten the optical overall length at the telephoto end while ensuring a predetermined magnification ratio.

On the other hand, when the value of the conditional expression (16) exceeds the upper limit value, the amount of movement of the final lens group at the time of scaling increases. At this time, if the lens barrel has a nested structure in which the inner cylinder part is housed in the outer cylinder part, if the lens barrel length is designed according to the total optical length at the wide-angle end, the inner cylinder part is doubled and the outer cylinder part is doubled. The structure of the lens barrel becomes complicated, and the outer diameter of the lens barrel becomes large, making it difficult to reduce the size.

In order to obtain the above effect, the upper limit of the conditional expression (16) is preferably 0.27, more preferably 0.21, and even more preferably 0.18.

1-3-17. Conditional expression (17)
-0.50 ≤ fpMax / f1 ≤ -0.05 ... (17)
However,
fpMax: Focal length of the lens group with the strongest positive refractive power among the lens groups included in the intermediate group f1: Focal length of the first lens group

The above conditional expression (17) is a conditional expression that defines the ratio between the focal length of the lens group having the strongest positive refractive power among the lens groups included in the intermediate group and the focal length of the first lens group. By satisfying the conditional expression (17), it is possible to increase the scaling effect of the lens group LpMax. Further, it becomes possible to shorten the amount of movement of each lens group in the variable magnification, and it becomes easy to realize the shortening of the optical total length.

On the other hand, when the value of the conditional expression (17) becomes less than the lower limit value, the refractive power of the first lens group becomes too strong with respect to the refractive power of the lens group LpMax, or the refractive power of the first lens group becomes too strong. On the other hand, the refractive power of the lens group LpMax becomes too weak. When the refractive power of the lens group LpMax becomes relatively weak, it is necessary to increase the optical total length of the zoom lens. When the refractive power of the first lens group becomes relatively weak, it is necessary to arrange a lens having a large lens diameter on the object side among the lenses constituting the first lens group in order to achieve a wide angle of view at the wide-angle end. Therefore, it becomes difficult to reduce the size in the radial direction. On the other hand, when the value of the conditional expression (17) exceeds the upper limit value, the refractive power of the lens group LpMax becomes too strong with respect to the refractive power of the first lens group. In this case, it becomes difficult to correct spherical aberration, and it becomes difficult to realize a zoom lens having high optical performance.

In order to obtain the above effect, the lower limit of the conditional expression (17) is preferably −0.48, more preferably −0.46, and even more preferably −0.44. The upper limit of the conditional expression (17) is preferably −0.10, more preferably −0.15, and even more preferably −0.20.

1-3-18. Conditional expression (18)
0.40 ≤ fpt / ft ≤ 2.00 ... (18)
However,
fpt: Focal length of the middle group at the telephoto end ft: Focal length at infinity focusing at the telephoto end of the zoom lens

The above conditional expression (18) is a conditional expression that defines the ratio between the focal length of the intermediate group at the telephoto end and the focal length at the telephoto end of the zoom lens at infinity focusing. By satisfying the conditional expression (18), it becomes possible to obtain a power arrangement having a strong tendency toward telephoto, and it becomes easy to shorten the optical overall length.

On the other hand, if the value of the conditional expression (18) is less than the lower limit value, the refractive power of the intermediate group becomes too strong, and it becomes difficult to correct the spherical aberration, which is not preferable. On the other hand, if the value of the conditional expression (18) exceeds the upper limit value, the total length becomes long and it becomes difficult to reduce the size.

In order to obtain the above effect, the lower limit of the conditional expression (18) is preferably −0.45, more preferably −0.50, and even more preferably −0.65. The upper limit of the conditional expression (18) is preferably 1.90, more preferably 1.80, still more preferably 1.70, and even more preferably 1.50.

1-3-19. Conditional expression (19)
-1.35 ≤ fn1 / fpt ≤ -0.05 ... (19)
However,
fpt: Focal length of the middle group at the telephoto end fn1: Focal length of the lens group LN

The above conditional expression (19) is a conditional expression that defines the ratio between the focal length of the lens group LN and the focal length of the intermediate group at the telephoto end. By satisfying the conditional expression (19), it becomes possible to obtain a power arrangement having a strong tendency toward telephoto, and it becomes easy to shorten the optical overall length.

On the other hand, if the value of the conditional expression (19) is less than the lower limit value, the refractive power of the lens group LN becomes too strong, and it becomes difficult to correct distortion and coma, which is not preferable. In addition, the height of the peripheral light rays in the final lens group arranged on the image side of the lens group LN becomes higher. Further, the final lens group arranges a lens having a large lens diameter on the image side, which makes it difficult to reduce the size in the radial direction. On the other hand, if the value of the conditional expression (19) exceeds the upper limit value, the total length becomes long and it becomes difficult to reduce the size.

In order to obtain the above effect, the lower limit of the conditional expression (19) is preferably -1.30, more preferably -1.25, and even more preferably -0.65. The upper limit of the conditional expression (19) is preferably −0.10, more preferably −0.15, and even more preferably −0.20.

2. 2. Image pickup device Next, the image pickup device according to the present invention will be described. The image pickup apparatus according to the present invention is characterized by comprising the zoom lens according to the present invention and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal. The image sensor is preferably provided on the image side of the zoom lens.

Here, the image pickup device and the like are not particularly limited, and a solid-state image pickup device such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor can also be used. The image pickup device according to the present invention is suitable for an image pickup device using these solid-state image pickup elements such as a digital camera and a video camera. Further, the image pickup device can be applied to various image pickup devices such as a single-lens reflex camera, a mirrorless single-lens camera, a digital still camera, a surveillance camera, an in-vehicle camera, and a drone-mounted camera. Further, these image pickup devices may be interchangeable lens type image pickup devices, or may be lens-fixed image pickup devices in which a lens is fixed to a housing. In particular, the zoom lens according to the present invention is suitable for a zoom lens of an image pickup device equipped with a large image pickup element such as a full size. Since the zoom lens is small and lightweight as a whole and has high optical performance, it is possible to obtain a high-quality image even when the zoom lens for such an image pickup device is used.

FIG. 25 is a diagram schematically showing an example of the configuration of the image pickup apparatus 1. The camera 2 includes a detachable zoom lens 3, an image pickup element 21 (CCD sensor or CMOS sensor) arranged on the image plane IP of the zoom lens 3, and a cover glass 22 arranged on the object side of the image pickup element 21. Yes. The zoom lens 3 has an aperture stop 31.

Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.

(1) Optical Configuration FIG. 1 is a cross-sectional view of the zoom lens of Example 1 according to the present invention at the wide-angle end and the telephoto end at infinity focusing. The zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a negative refractive power, and a positive refractive power in this order from the object side. It is composed of a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a negative refractive power.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 first moves to the image side and then moves to the object side, the second lens group G2 moves to the object side, and the third lens group G3 does not move. The fourth lens group G4 moves to the object side, the fifth lens group G5 moves to the object side, and the sixth lens group G6 moves to the object side. Further, during zooming, the fourth lens group G4 and the sixth lens group G6 move in the same orbit.

When focusing from an infinity object to a nearby object, the fifth lens group G5 moves from the object side to the image side along the optical axis.

The aperture stop S is arranged adjacent to the object side of the third lens group G3.

In this embodiment, the intermediate group is a group consisting of a second lens group G2, a third lens group G3, and a fourth lens group G4, and the lens group LpMax is a fourth lens group G4. The lens group LN is the fifth lens group G5, and the final lens group is the sixth lens group G6. The fourth lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 is composed of a negative meniscus lens L101 having a convex shape on the object side, a biconcave lens L102, and a positive meniscus lens L103 having an aspherical surface on both sides in order from the object side.

The second lens group G2 is composed of a biconvex lens L104 having aspherical surfaces on both sides, a negative meniscus lens L105 having a concave object side, and a biconvex lens L106 in order from the object side.

The third lens group G3 is composed of an aperture diaphragm S, a biconcave lens L107 having an aspherical surface on the surface of the object side, a biconvex lens L108, and a biconcave lens L109 in order from the object side.

The fourth lens group G4 is composed of a biconvex lens L110, a biconvex lens L111, and a biconvex lens L112 having aspherical surfaces on both sides in order from the object side.

The fifth lens group G5 is composed of a negative meniscus lens L113 having a convex shape on the object side and a positive meniscus lens L114 having a convex shape on the object side having an aspherical surface on the surface on the object side, in order from the object side.

The sixth lens group G6 is composed of a biconvex lens L115 and a negative meniscus lens L116 having a concave object side in order from the object side.

In this embodiment, L1p of the present application is the lens L103, LpMp is the lens L111, LnL is the lens L116, and CrGLf is the image-side surface of the lens L103. ..

In FIG. 1, “IP” is an image plane, and specifically, indicates an image pickup surface of a solid-state image pickup device such as a CCD sensor or a CMOS sensor, or a film surface of a silver halide film. Further, a parallel flat plate having no substantial refractive power such as a cover glass CG is provided on the object side of the image plane IP. Further, in FIG. 1, the addition of reference numerals to the lenses constituting each lens group is omitted. Since these points are the same in the cross-sectional views of each lens shown in the other examples, the description thereof will be omitted below.

(2) Numerical Example Next, a numerical example to which a specific numerical value of the zoom lens is applied will be described. The following shows "lens data", "specification table", "variable interval", "aspherical coefficient", and "lens group data". Further, the values of each conditional expression (Table 1) and various numerical values and the like (Table 2) used to obtain the values of each conditional expression are collectively shown after Example 6.

In (lens data), "plane number" is the order of the lens surfaces counted from the object side, "R" is the radius of curvature of the lens surface, "D" is the lens wall thickness or air spacing on the optical axis, and "Nd" is. The refractive index at the d-line (wavelength λ = 587.6 nm), “ABV” indicates the Abbe number at the d-line. Further, in the "plane number" column, "ASP" attached next to the plane number indicates that the lens surface is an aspherical surface, and "S" indicates that the surface is an aperture stop. In the column of "D", "D (6)", "D (12)" and the like mean that the distance on the optical axis of the lens surface is a variable distance that changes at the time of scaling. Further, "0.0000" in the column of radius of curvature means infinity, which means that the lens surface is a plane.

In the (specification table), "f" is the focal length of the zoom lens, "Fno" is the F number, "W" is the half angle of view, "Y" is the image height, and "TL" is the optical total length. The values at the wide-angle end, intermediate focal length, and telephoto end are shown, respectively.

In (variable interval), the values at the wide-angle end, the intermediate focal length, and the telephoto end at infinity are shown. The same applies to the other examples.

(Aspherical coefficient) indicates the aspherical coefficient when the aspherical shape is defined as follows. However, x is the amount of displacement from the reference plane in the optical axis direction, r is the paraxial radius of curvature, H is the height from the optical axis in the direction perpendicular to the optical axis, k is the conical coefficient, and An is the nth-order aspherical surface. Let it be a coefficient. Further, in the table of "aspherical coefficient", "E ± XX" represents exponential notation and means ^{"× 10 ± XX".}

Since the matters in each of these tables are the same in each table shown in other examples, the description thereof will be omitted below.

In addition, FIGS. 2, 3 and 4 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length and telephoto end of the zoom lens. The longitudinal aberration diagrams shown in each figure are spherical aberration (mm), astigmatism (mm), and distortion (%), respectively, in order from the left side when facing the drawing. In the spherical aberration diagram, the solid line shows the spherical aberration at the d line (wavelength 587.6 nm), the broken line shows the F line (wavelength 486.1 nm), and the dotted line shows the spherical aberration at the C line (wavelength 656.3 nm). In the astigmatism diagram, the vertical axis is the half angle of view (ω), the horizontal axis is the defocus, the solid line shows the sagittal image plane (S) of the d line, and the broken line shows the meridional image plane (M) of the d line. show. In the distortion diagram, the vertical axis is the half angle of view (ω) and the horizontal axis is the distortion. Since these matters are the same in each aberration diagram shown in other examples, the description thereof will be omitted below.

(Lens data)
Surface number RD Nd ABV
1 124.1004 2.0000 1.69680 55.46
2 32.7464 10.5157
3 -346.5647 2.0000 1.49700 81.61
4 47.0039 2.8357
5 ASP 64.0822 3.9531 1.88202 37.22
6 ASP 213.0728 D (6)
7 ASP 229.6363 4.0489 1.72916 54.67
8 ASP -67.1566 1.6500
9 -63.2719 1.5000 1.92286 20.88
10 -2259.4237 0.1000
11 66.3043 5.6238 1.72916 54.67
12 -76.8959 D (12)
13 S 0.0000 3.3554
14 ASP -60.0156 0.2000 1.53610 41.21
15 -62.4762 1.2000 1.70154 41.15
16 45.4814 1.6081
17 48.1506 3.6658 1.98613 16.48
18 -991.4188 4.3046
19 -34.3709 1.2000 1.78472 25.72
20 1578.8626 D (20)
21 57.1212 3.8884 1.49700 81.61
22 -625.9645 0.1000
23 32.6298 8.3899 1.49700 81.61
24 -53.2937 0.1000
25 ASP 137.3913 2.3668 1.88202 37.22
26 ASP -152.6159 D (26)
27 197.2996 1.2000 1.85883 30.00
28 32.7802 2.0643
29 ASP 40.1582 0.2000 1.53610 41.21
30 42.4092 2.2574 1.72916 54.67
31 58.5890 D (31)
32 62.1969 8.3641 1.49700 81.61
33 -31.5909 6.3018
34 -27.0088 1.5000 1.83400 37.34
35 0.0000 D (35)
36 0.0000 2.5000 1.51680 64.20
37 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 25.78 35.45 48.51
Fno 2.06 2.06 2.06
W 41.07 31.21 23.00
Y 20.61 21.63 21.63
TL 150.05 145.05 144.82

(Variable interval)
Wide-angle end Middle telephoto end
D (5) 1.0000 29.5878 60.1049
D (14) 40.7065 16.2511 1.0000
D (31) 0.9807 9.3356 8.9082
D (34) 30.4459 22.091 22.5184
D (37) 14.4999 32.4611 49.0997

(Aspherical coefficient)
Surface number K A4 A6 A8 A10
5 -6.01225E + 00 1.52917E-06 3.46595E-09 -7.48207E-12 6.68959E-15
6 5.69139E + 00 -2.68169E-06 4.29674E-09 -8.47722E-12 7.09503E-15
7 0.00000E + 00 -7.10488E-07 -9.43179E-10 -2.96672E-12 0.00000E + 00
8 0.00000E + 00 8.01634E-07 -1.01577E-09 -2.30382E-12 0.00000E + 00
14 0.00000E + 00 5.29970E-06 -2.26478E-09 1.47060E-12 0.00000E + 00
25 0.00000E + 00 -1.03549E-05 -2.65374E-09 2.20566E-10 -6.43627E-13
26 0.00000E + 00 2.11307E-06 3.44455E-09 2.26640E-10 -6.86047E-13
29 0.00000E + 00 -3.10161E-07 3.58551E-09 -3.63278E-11 0.00000E + 00

(Lens group data)
Group surface number Focal length
G1 1-6 -56.82
G2 7-12 50.68
G3 14-20 -33.56
G4 21-26 23.74
G5 27-31 -61.94
G6 32-35 -500.00

(1) Optical Configuration FIG. 5 is a cross-sectional view of the zoom lens of the second embodiment according to the present invention at the wide-angle end and the telephoto end at infinity focusing. The zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a negative refractive power, and a positive refractive power in this order from the object side. It is composed of a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a negative refractive power.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 does not move and is fixed, the second lens group G2 moves to the object side, the third lens group G3 moves to the object side, and the fourth lens group G1 moves to the object side. The lens group G4 moves to the object side, the fifth lens group G5 moves to the object side, and the sixth lens group G6 moves to the object side. Further, during zooming, the fourth lens group G4 and the sixth lens group G6 move in the same orbit.

When focusing from an infinity object to a nearby object, the fifth lens group G5 moves from the object side to the image side along the optical axis.

The aperture stop S is arranged adjacent to the object side of the third lens group G3.

In this embodiment, the intermediate group is a group consisting of a second lens group G2, a third lens group G3, and a fourth lens group G4, and the lens group LpMax is a fourth lens group G4. The lens group LN is the fifth lens group G5, and the final lens group is the sixth lens group G6. The fourth lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 is, in order from the object side, from the object side convex negative meniscus lens L201, the object side convex negative meniscus lens L202, and the object side convex positive meniscus lens L203 having aspherical surfaces on both sides. It is composed.

The second lens group G2 is composed of a biconvex lens L204 having aspherical surfaces on both sides, a negative meniscus lens L205 having a concave object side, and a biconvex lens L206 in order from the object side.

The third lens group G3 is composed of an aperture diaphragm S, a junction lens in which a biconcave lens L207 and a biconvex lens L208 are joined, and a biconcave lens L209 having an aspherical surface on the surface on the object side, in order from the object side. ..

The fourth lens group G4 is composed of a biconvex lens L210, a junction lens in which a negative meniscus lens L211 having a convex shape on the object side and a biconvex lens L212 are joined in order from the object side, and a biconvex lens L213 having aspherical surfaces on both sides. Has been done.

The fifth lens group G5 is composed of a negative meniscus lens L214 having a convex shape on the object side.

The sixth lens group G6 is composed of a biconvex lens L215 and a negative meniscus lens L216 having a concave object side in order from the object side.

In this embodiment, L1p of the present application is the lens L203, LpMp is the lens L210, LnL is the lens L216, and CrGLf is the image-side surface of the lens L203. ..

(2) Numerical Examples Next, as numerical examples to which specific numerical values of the zoom lens are applied, "lens data", "specification table", "variable spacing", "aspherical coefficient", and "lens group data". ". In addition, FIGS. 6, 7, and 8 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length, and telephoto end of the zoom lens.

(Lens data)
Surface number RD Nd ABV
1 113.2329 2.0000 1.69680 55.46
2 28.9918 14.5759
3 1100.4655 2.0000 1.49700 81.61
4 40.9545 3.8366
5 ASP 67.6631 4.9844 1.88202 37.22
6 ASP 263.7182 D (6)
7 ASP 353.4183 3.5852 1.70338 56.13
8 ASP -72.9016 2.3235
9 -46.8700 1.5000 1.92286 20.88
10 -100.4699 0.1000
11 108.2828 4.7848 1.72916 54.67
12 -61.7328 D (12)
13 S 0.0000 2.6692
14 -79.9400 1.2000 1.69453 33.74
15 24.8547 3.9977 1.92286 20.88
16 -226.1765 2.8711
17 ASP -32.1322 1.2000 1.78431 29.92
18 115.3058 D (18)
19 30.3491 4.1422 1.56061 69.42
20 -488.3397 0.1000
21 64.3308 1.0000 1.92123 22.09
22 30.6549 6.0126 1.49715 81.57
23 -47.3036 0.1000
24 ASP 47.7491 3.2661 1.60787 63.65
25 ASP -150.4366 D (25)
26 1000.2287 1.2000 1.49700 81.61
27 28.9539 D (27)
28 106.6910 4.9866 1.54830 50.74
29 -45.8170 2.2484
30 -35.8488 1.5000 1.69842 55.08
31 -1854.8498 D (31)
32 0.0000 13.1500
33 0.0000 2.5000 1.51680 64.20
34 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 20.60 32.56 48.51
Fno 2.88 2.88 2.88
W 48.36 33.40 23.02
Y 19.68 21.63 21.63
TL 150.00 150.00 150.00

(Variable interval)
Wide-angle end Middle telephoto end
D (6) 36.5041 18.4579 2.2359
D (12) 2.0000 16.1729 28.1780
D (18) 7.0006 4.7795 2.0000
D (25) 5.8909 2.3950 2.5056
D (27) 5.6703 9.1662 9.0555
D (31) 0.1000 6.1943 13.1907

(Aspherical coefficient)
Surface number K A4 A6 A8 A10
5 -2.41245E + 00 1.68633E-06 1.86228E-09 -3.84080E-13 3.03302E-15
6 9.66380E + 00 -1.19783E-06 8.14054E-10 3.91400E-13 3.30443E-16
7 0.00000E + 00 -3.29731E-06 6.24380E-09 -1.31483E-11 0.00000E + 00
8 0.00000E + 00 -2.61691E-06 6.16884E-09 -1.23535E-11 0.00000E + 00
17 0.00000E + 00 4.93529E-06 7.76897E-09 -4.63230E-11 0.00000E + 00
24 0.00000E + 00 -7.39682E-06 -3.12310E-08 -1.33183E-10 5.47014E-13
25 0.00000E + 00 1.16420E-05 -2.36695E-08 -1.11278E-10 7.57203E-13

(Lens group data)
Group number Focal length
G1 1-6 -52.16
G2 7-12 51.85
G3 14-18 -37.90
G4 19-25 23.21
G5 26-27 -60.02
G6 28-31 -866.15

(1) Optical Configuration FIG. 9 is a cross-sectional view of the zoom lens according to the third embodiment of the present invention at the wide-angle end and the telephoto end at infinity focusing. The zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, and a negative refractive power in order from the object side. It is composed of a fourth lens group G4 having a negative refractive power and a fifth lens group G5 having a negative refractive power.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 first moves to the image side and then to the object side, the second lens group G2 moves to the object side, and the third lens group G3 moves to the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 moves to the object side.

When focusing from an infinity object to a nearby object, the fourth lens group G4 moves from the object side to the image side along the optical axis.

The aperture stop S is arranged adjacent to the object side of the third lens group G3.

In this embodiment, the intermediate group is a group consisting of a second lens group G2 and a third lens group G3, and the lens group LpMax is a third lens group G3, and the lens group LN. Is the 4th lens group G4, and the final lens group is the 5th lens group G5. The third lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 is composed of a biconcave lens L301, a negative meniscus lens L302 having a convex shape on the object side, and a biconvex lens L303 having aspherical surfaces on both sides, in order from the object side.

The second lens group G2 is composed of a biconvex lens L304 having aspherical surfaces on both sides, a negative meniscus lens L305 having a concave object side, and a biconvex lens L306 in order from the object side.

The third lens group G3 includes an aperture stop S, a junction lens in which a biconcave lens L307 and a biconvex lens L308 are joined, a biconcave lens L309 having an aspherical surface on the object side surface, and a biconvex lens L310 in order from the object side. It is composed of a bonded lens in which a negative meniscus lens L311 having a convex shape on the object side and a biconvex lens L312 are bonded, and a biconvex lens L313 having an aspherical surface on both sides.

The fourth lens group G4 is composed of a biconcave lens L314.

The fifth lens group G5 is composed of a positive meniscus lens L315 having a concave shape on the object side and a negative meniscus lens L316 having a concave shape on the object side in order from the object side.

In this embodiment, L1p of the present application is the lens L303, LpMp is the lens L310, LnL is the lens L316, and CrGLf is the image-side surface of the lens L303. ..

(2) Numerical Examples Next, as numerical examples to which specific numerical values of the zoom lens are applied, "lens data", "specification table", "variable spacing", "aspherical coefficient", and "lens group data". ". In addition, FIGS. 10, 11 and 12 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length and telephoto end of the zoom lens.

(Lens data)
Surface number RD Nd ABV
1 -2236.7015 2.0000 1.69680 55.46
2 27.3449 11.7237
3 249.8646 2.0000 1.49700 81.61
4 56.2626 4.3892
5 ASP 666.8413 5.8788 1.88202 37.22
6 ASP -90.7339 D (6)
7 ASP 122.9237 3.6737 1.72917 54.67
8 ASP -99.3509 3.5122
9 -34.6395 1.5000 1.92286 20.88
10 -66.3126 0.1000
11 290.8205 8.4371 1.72916 54.67
12 -41.4174 D (12)
13 S 0.0000 2.8414
14 -44.7019 1.2000 1.70085 34.48
15 29.9927 4.4622 1.92286 20.88
16 -91.2906 2.1384
17 ASP -125.1747 1.2000 1.78796 30.34
18 31.8452 5.9742
19 40.8206 4.9661 1.56823 68.35
20 -82.6639 0.1000
21 104.6105 1.0000 1.91901 23.79
22 38.6544 7.4729 1.50803 78.95
23 -27.9405 0.1000
24 ASP 237.9555 4.1714 1.63691 60.91
25 ASP -35.1031 D (25)
26 -156.7844 1.2000 1.49700 81.61
27 24.6262 D (27)
28 -240.7169 5.5480 1.63943 33.54
29 -24.7233 0.1000
30 -30.8315 1.5000 2.00100 29.13
31 -739.3576 D (31)
32 0.0000 13.1500
33 0.0000 2.5000 1.51680 64.20
34 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 20.60 29.12 38.81
Fno 2.88 2.88 2.88
W 48.36 37.03 27.97
Y 19.68 21.63 21.63
TL 150.00 144.53 146.59

(Variable interval)
Wide-angle end Middle telephoto end
D (6) 31.6350 12.9055 2.0000
D (12) 2.0000 13.2119 22.3626
D (25) 4.6309 3.4430 2.0000
D (27) 6.6861 7.1924 7.8817
D (31) 1.2088 3.9403 8.5061

(Aspherical coefficient)
Surface number K A4 A6 A8 A10
5 1.00000E + 01 9.69921E-06 -9.70199E-09 1.60672E-11 -1.36358E-14
6 -1.56748E + 00 5.20654E-06 -9.88038E-09 1.29752E-11 -1.36136E-14
7 0.00000E + 00 -9.03623E-06 -4.56900E-09 2.22950E-11 0.00000E + 00
8 0.00000E + 00 -8.12098E-06 1.98512E-09 2.01792E-11 0.00000E + 00
17 0.00000E + 00 -1.89534E-05 1.21170E-08 -1.05762E-10 0.00000E + 00
24 0.00000E + 00 -6.50834E-06 -4.31965E-08 1.99772E-10 3.36191E-14
25 0.00000E + 00 8.96935E-06 -3.60234E-08 1.65609E-10 2.62714E-13

(Lens group data)
Group number Focal length
G1 1-6 -56.93
G2 7-12 49.69
G3 14-25 23.69
G4 26-27 -42.73
G5 28-31 -127.05

(1) Optical Configuration FIG. 13 is a cross-sectional view of the zoom lens of Example 4 according to the present invention at the wide-angle end and the telephoto end at infinity focusing. The zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a negative refractive power, and a negative refractive power in order from the object side. It is composed of a fourth lens group G4 having the above.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side, the second lens group G2 moves to the object side, the third lens group G3 moves to the object side, and the fourth lens group moves. G4 moves to the object side.

When focusing from an infinity object to a nearby object, the third lens group G3 moves from the object side to the image side along the optical axis.

The aperture stop S is arranged in the second lens group G2.

In this embodiment, the intermediate group is the second lens group G2, the lens group LpMax is the second lens group G2, and the lens group LN is the third lens group G3. That is, the final lens group is the fourth lens group G4. The second lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L401 having a convex shape on the object side, a biconcave lens L402 having an aspherical surface on the image side surface, and a positive meniscus lens L402 having an aspherical surface on both sides. It is composed of a lens L403.

In the second lens group G2, the positive meniscus lens L404 having a convex shape on the object side, the aperture stop S, the negative meniscus lens L405 having a convex shape on the object side, and the positive meniscus lens L406 having a convex shape on the object side are joined in this order from the object side. It is composed of a bonded lens and a biconvex lens L407 having aspherical surfaces on both sides.

The third lens group G3 is composed of a biconcave lens L408.

The fourth lens group G4 is composed of a biconvex lens L409, an object-side concave negative meniscus lens L410, and an object-side concave negative meniscus lens L411 having aspherical surfaces on both sides, in order from the object side.

In this embodiment, L1p of the present application is the lens L403, LpMp is the lens L407, LnL is the lens L411, and CrGLf is the image-side surface of the lens L403. ..

(2) Numerical Examples Next, as numerical examples to which specific numerical values of the zoom lens are applied, "lens data", "specification table", "variable spacing", "aspherical coefficient", and "lens group data". ". In addition, FIGS. 14, 15 and 16 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length and telephoto end of the zoom lens.

(Lens data)
Surface number RD Nd ABV
1 60.6706 2.0000 1.69680 55.46
2 22.0000 12.1130
3-203.7986 2.0000 1.49700 81.61
4 ASP 21.5856 3.6638
5 ASP 32.6755 5.2332 1.88202 37.22
6 ASP 61.9904 D (6)
7 37.8621 2.9348 1.72916 54.67
8 178.6874 2.3629
9 S 0.0000 3.7933
10 22.4993 1.2000 1.91124 34.42
11 12.8888 6.5006 1.57505 67.44
12 85.8581 10.0754
13 ASP 27.3823 5.7808 1.49700 81.61
14 ASP -24.7300 D (14)
15 -61.8097 1.2000 1.72916 54.67
16 34.4138 D (16)
17 375.9690 5.0605 1.68460 43.79
18 -19.8398 0.2986
19 -24.9204 1.5000 1.91082 35.25
20 -64.7824 4.3005
21 ASP -30.3891 1.5000 1.85135 40.10
22 ASP -84.9035 D (22)
23 0.0000 13.1500
24 0.0000 2.5000 1.51680 64.20
25 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 20.60 29.15 38.80
Fno 2.88 2.88 2.88
W 48.28 36.90 27.98
Y 20.03 21.59 21.63
TL 123.99 113.14 107.70

(Variable interval)
Wide-angle end Middle telephoto end
D (6) 30.1383 13.2308 2.0000
D (14) 2.0001 3.7100 5.9959
D (16) 3.5842 5.4743 7.4542
D (22) 0.1000 2.5597 4.0776

(Aspherical coefficient)
Surface number K A4 A6 A8 A10
4-4.07902E + 00 5.20396E-05 -1.01831E-07 1.84887E-10 0.00000E + 00
5 -6.79657E + 00 2.83309E-05 -5.33579E-08 1.19865E-10 -1.46658E-14
6 3.44746E + 00 -1.91082E-06 -1.05921E-08 5.89406E-11 -8.29321E-14
13 0.00000E + 00 -2.44644E-05 -3.39046E-08 -3.44484E-10 0.00000E + 00
14 0.00000E + 00 5.31260E-06 -3.71272E-08 -3.31959E-10 0.00000E + 00
21 0.00000E + 00 -9.04175E-05 5.73366E-08 -9.26258E-11 0.00000E + 00
22 0.00000E + 00 -6.68157E-05 1.69679E-07 -9.20940E-11 0.00000E + 00

(Lens group data)
Group surface number Focal length
G1 1-6 -29.66
G2 7-14 25.13
G3 15-16 -30.16
G4 17-22 -400.01

(1) Optical Configuration FIG. 17 is a cross-sectional view of the zoom lens of Example 5 according to the present invention at the wide-angle end and the telephoto end at infinity focusing. In the zoom lens, the zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power in this order from the object side. It is composed of a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a negative refractive power.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 does not move and is fixed, the second lens group G2 moves to the object side, and the aperture stop S does not move and is fixed. The lens group G3 moves to the image side, the fourth lens group G4 does not move and is fixed, the fifth lens group G5 moves to the object side, and the sixth lens group G6 does not move and is fixed.

When focusing from an infinity object to a nearby object, the fifth lens group G5 moves from the object side to the image side along the optical axis.

The aperture stop S is independently arranged between the second lens group G2 and the third lens group G3.

In this embodiment, the intermediate group is a group consisting of a second lens group G2, a third lens group G3, and a fourth lens group G4, and the lens group LpMax is a fourth lens group G4. The lens group LN is the fifth lens group G5, and the final lens group is the sixth lens group G6. The fourth lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 is composed of a biconcave lens L501, an object-side convex negative meniscus lens L502 having an aspherical surface on the image-side surface, and an object-side convex negative meniscus lens L503 in order from the object side. There is.

The second lens group G2 is composed of a bonded lens in which a biconvex lens L504 and a negative meniscus lens L505 having a concave object side are bonded, and a biconvex lens L506.

The third lens group G3 includes a junction lens in which a biconcave lens L507 and a biconvex lens L508 are joined in order from the object side, a biconcave lens L509 having an aspherical surface on the object side surface, and a positive meniscus lens having a convex shape on the object side. It is composed of L510.

The fourth lens group G4 is composed of a biconvex lens L511 having aspherical surfaces on both sides, and a bonded lens in which a biconvex lens L512 and a negative meniscus lens L513 having a concave object side are joined in order from the object side.

The fifth lens group G5 is composed of a biconcave lens L514 having aspherical surfaces on both sides.

The sixth lens group G6 is composed of a positive meniscus lens L515 having a concave shape on the object side and a biconcave lens L516 in this order from the object side.

In this embodiment, L1p of the present application is the lens L503, LpMp is the lens L511, LnL is the lens L516, and CrGLf is the image-side surface of the lens L503. ..

(2) Numerical Examples Next, as numerical examples to which specific numerical values of the zoom lens are applied, "lens data", "specification table", "variable spacing", "aspherical coefficient", and "lens group data". ". In addition, FIGS. 18, 19 and 20 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length and telephoto end of the zoom lens.

(Lens data)
Surface number RD Nd ABV
1 -432.5690 2.0000 1.65534 44.20
2 44.8660 4.3979
3 83.2788 2.0000 1.49700 81.61
4 ASP 31.4343 4.4655
5 63.9196 3.1569 1.75404 28.91
6 174.6629 D (6)
7 69.3596 6.5632 1.58528 66.16
8-56.0044 1.0000 1.92286 20.88
9 -113.4602 2.6930
10 44.5856 5.5502 1.59382 66.96
11 -681.0575 D (11)
12 S 0.0000 D (12)
13 -174.8844 1.0000 1.83913 35.38
14 40.7918 3.9572 1.85347 22.43
15 -47.1043 1.5540
16 ASP -24.4495 1.2000 1.91004 35.29
17 47.4411 0.3120
18 46.9147 2.0248 1.92286 20.88
19 83.1280 D (19)
20 ASP 60.2483 5.8432 1.58749 65.90
21 ASP -26.0922 0.0744
22 70.2837 6.9800 1.49700 81.61
23 -25.0067 1.0000 1.89211 21.51
24 -40.0619 D (24)
25 ASP -168.1626 1.0000 1.69260 53.24
26 ASP 76.7232 D (26)
27 -173.3234 4.3046 1.91925 23.76
28 -36.8857 0.1892
29 -48.8379 1.0000 1.75776 25.64
30 53.3950 15.9159
31 0.0000 2.5000 1.51680 64.20
32 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 28.85 46.44 72.67
Fno 2.88 2.88 2.88
W 38.14 24.64 15.79
Y 19.91 21.63 21.63
TL 140.00 140.00 140.00

(Variable interval)
Wide-angle end Middle telephoto end
D (6) 27.2265 14.5929 2.1783
D (11) 2.2955 14.9291 27.3436
D (12) 2.1782 6.4295 11.7481
D (19) 11.7372 7.4859 2.1673
D (24) 8.4438 5.2820 4.4632
D (26) 6.4369 9.5988 10.4176

(Aspherical coefficient)
Surface number K A4 A6 A8 A10
4 0.00000E + 00 -4.12067E-06 -3.05369E-09 -1.84090E-12 0.00000E + 00
16 0.00000E + 00 7.62098E-06 1.35010E-08 -2.35354E-11 0.00000E + 00
20 0.00000E + 00 -3.02504E-06 -6.95946E-09 6.02111E-12 0.00000E + 00
21 0.00000E + 00 1.16203E-05 -8.87540E-09 2.23704E-12 0.00000E + 00
25 0.00000E + 00 3.92682E-06 -4.92977E-08 1.21563E-10 0.00000E + 00
26 0.00000E + 00 3.84781E-06 -2.70552E-08 8.56004E-11 0.00000E + 00

(Lens group data)
Group surface number Focal length
G1 1-6 -55.58
G2 7-11 42.25
G3 13-19 -29.60
G4 20-24 23.24
G5 25-26 -75.94
G6 27-30 -100.00

(1) Optical Configuration FIG. 21 is a cross-sectional view of the zoom lens of the sixth embodiment according to the present invention at the wide-angle end and the telephoto end at infinity focusing. The zoom lens has a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, and a negative refractive power in order from the object side. It is composed of a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a positive refractive power, a sixth lens group G6 having a negative refractive power, and a seventh lens group G7 having a negative refractive power.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 does not move and is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the aperture aperture is stopped down. S does not move and is fixed, the fourth lens group G4 moves to the image side, the fifth lens group G5 does not move and is fixed, the sixth lens group G6 moves to the object side, and the seventh lens group G6 moves to the object side. The lens group G7 does not move and is fixed.

When focusing from an infinity object to a nearby object, the sixth lens group G6 moves from the object side to the image side along the optical axis.

The aperture stop S is independently arranged between the third lens group G3 and the fourth lens group G4.

In this embodiment, the intermediate group is a group consisting of a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, and the lens group LpMax is a fifth lens group. The lens group G5, the lens group LN is the sixth lens group G6, and the final lens group is the seventh lens group G7. The fifth lens group is a lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Hereinafter, the configuration of each lens group will be described.

The first lens group G1 is composed of a plano-concave lens L601 whose object side is flat.

The second lens group G2 is composed of an object-side convex negative meniscus lens L602 having an aspherical surface on the image-side surface and an object-side convex positive meniscus lens L603 in order from the object side.

The third lens group G3 is composed of a bonded lens in which a biconvex lens L604 and a negative meniscus lens L605 having a concave object side are bonded, and a biconvex lens L606.

The fourth lens group G4 includes a junction lens in which a biconcave lens L607 and a biconvex lens L608 are joined in order from the object side, a biconcave lens L609 having an aspherical surface on the object side surface, and a positive meniscus lens having a convex shape on the object side. It is composed of L610.

The fifth lens group G5 is composed of a biconvex lens L611 having aspherical surfaces on both sides, and a bonded lens in which a biconvex lens L612 and a negative meniscus lens L613 having a concave object side are joined in order from the object side.

The sixth lens group G6 is composed of a biconcave lens L614 having aspherical surfaces on both sides in order from the object side.

The seventh lens group G7 is composed of a negative meniscus lens L615 having a convex shape on the object side in order from the object side.

In this embodiment, the LpMp of the present application is the lens L611, the LnL is the lens L615, and the CrGLf is the image-side surface of the lens L601.

(2) Numerical Examples Next, as numerical examples to which specific numerical values of the zoom lens are applied, "lens data", "specification table", "variable spacing", "aspherical coefficient", and "lens group data". ". In addition, FIGS. 22, 23 and 24 show longitudinal aberration diagrams at infinity focusing at the wide-angle end, intermediate focal length and telephoto end of the zoom lens.

(Lens data)
Surface number RD Nd ABV
1 0.0000 2.0000 1.65595 43.41
2 31.5382 D (2)
3 46.1135 2.0000 1.55440 48.77
4 ASP 28.5329 2.2812
5 41.5798 3.4352 1.91920 23.80
6 70.6455 D (6)
7 70.3251 4.5885 1.58682 65.98
8 -55.2713 1.0000 1.92286 20.88
9 -132.0319 0.0000
10 46.8701 3.7754 1.59774 66.43
11 -166.9787 D (11)
12 S 0.0000 D (12)
13 -70.8026 1.0000 1.80147 43.76
14 146.7866 2.5860 1.86552 22.13
15 -55.7713 2.2797
16 ASP -29.3436 0.2000 1.53610 41.21
17 -28.1516 1.0000 1.90560 35.54
18 53.1008 0.3683
19 49.9701 2.3681 1.92286 20.88
20 198.2902 D (20)
21 ASP 58.1368 5.9408 1.59805 64.69
22 ASP -26.0328 0.0000
23 47.0802 6.1303 1.49700 81.61
24 -33.4750 1.0000 1.86259 22.20
25 -90.6067 D (25)
26 ASP -55.0870 1.0000 1.59807 66.39
27 ASP 137.2913 D (27)
28 329.2435 1.0000 1.77402 44.32
29 62.5860 0.0000
30 0.0000 16.1500
31 0.0000 2.5000 1.51680 64.20
32 0.0000 1.0000

(Specification table)
Wide-angle end Middle telephoto end
f 28.84 45.11 72.75
Fno 4.12 4.12 4.12
W 38.13 25.27 15.78
Y 19.92 21.63 21.63
TL 130.00 130.00 130.00

(Variable interval)
Wide-angle end Middle telephoto end
D (2) 4.0563 6.0563 8.0757
D (6) 31.8607 17.6273 2.0000
D (11) 2.0000 14.2334 27.8414
D (12) 2.2673 5.6919 10.6665
D (20) 10.3992 6.9746 2.0000
D (25) 9.4245 5.2401 2.5877
D (27) 6.3885 10.5729 13.2253

(Aspherical coefficient)
No. K A4 A6 A8 A10
4 0.00000E + 00 -3.61525E-06 -3.55159E-09 -6.20392E-12 0.00000E + 00
16 0.00000E + 00 2.80091E-06 -3.35294E-10 -1.75681E-11 0.00000E + 00
21 0.00000E + 00 -3.59063E-06 1.32767E-09 1.32009E-11 0.00000E + 00
22 0.00000E + 00 7.92222E-06 -1.41905E-09 3.59304E-11 0.00000E + 00
26 0.00000E + 00 -2.81203E-06 4.19731E-08 -1.27591E-10 0.00000E + 00
27 0.00000E + 00 -2.09918E-06 4.88511E-08 -1.25865E-10 0.00000E + 00

(Lens group data)
Group surface number Focal length
G1 1-2 -48.07
G2 3-6 426.48
G3 7-11 40.07
G4 13-20 -33.33
G5 21-25 24.24
G6 26-27 -65.61
G7 28-29 -100.00

[Table 1]
Conditional expression Example 1 Example 2 Example 3 Example 3 Example 4 Example 5 Example 6
Conditional expression (1) f1 / fpt -1.06 -1.01 -1.10 -1.18 -0.69 -0.65
Conditional expression (2) fpMax / fw 0.92 1.13 1.15 1.22 0.81 0.84
Conditional expression (3) f1 / fw -2.20 -2.53 -2.76 -1.44 -1.93 -1.67
Conditional expression (4) fn1 / ft -1.28 -1.24 -1.10 -0.78 -1.05 -0.90
Conditional expression (5) frt / ft 0.86 0.97 1.30 0.64 0.50 0.43
Conditional expression (6) fn12 / ft -0.91 -1.08 -0.78 -0.65 -0.55 -0.50
Conditional expression (7) βn1 1.78 1.50 1.60 2.03 1.33 1.35
Conditional expression (8) βn12 1.50 1.44 1.84 1.98 1.59 1.61
Conditional expression (9) | {1− (βn1 × βn1)} × (βn2 × βn2) |
1.55 1.15 2.05 2.97 1.10 1.18
Conditional expression (10) | CrG1r / fw | 8.26 12.80 4.41 3.01 6.05 1.09
Conditional expression (11) (fw × tanω) / BFw 1.42 1.46 1.36 1.45 1.22 1.20
Conditional expression (12) νdLpMp 81.61 69.42 68.35 81.61 65.90 64.69
Conditional expression (13) νdL1p 37.22 37.22 37.22 37.22 28.91-
Conditional expression (14) NdL1p 1.88 1.88 1.88 1.88 1.75-
Conditional expression (15) fLnL / ft -0.67 -1.08 -0.83 -1.45 -0.46 -1.37
Conditional expression (16) | BFt-BFw | / TLw 0.03 0.09 0.05 0.03 0.00 0.00
Conditional expression (17) fpMax / f1 -0.42 -0.44 -0.42 -0.85 -0.42 -0.50
Conditional expression (18) fpt / ft 1.10 1.06 1.33 0.65 1.11 1.01
Conditional expression (19) fn1 / fpt -1.06 -1.01 -1.10 -1.18 -0.69 -0.65

The zoom lens according to the present invention can be suitably applied as an image pickup optical system of an image pickup device such as a film camera, a digital still camera, and a digital video camera, for example.

S ・ ・ ・ Aperture aperture CG ・ ・ ・ Cover glass IP ・ ・ ・ Image plane G1 ・ ・ ・ First lens group G2 ・ ・ ・ Second lens group G3 ・ ・ ・ Third lens group G4 ・ ・ ・ Fourth lens group G5 ・ ・ ・ 5th lens group G6 ・ ・ ・ 6th lens group G7 ・ ・ ・ 7th lens group (W) ・ ・ ・ Wide-angle end (T) ・ ・ ・ Telescopic end 1 ・ ・ ・ Imaging device 2 ・ ・ ・Camera 3 ・ ・ ・ Lens 21 ・ ・ ・ Imaging element (CCD sensor or CMOS sensor)

Claims (16)

From the object side, a first lens group having a negative refractive power, an intermediate group consisting of one or more lens groups having a positive refractive power as a whole, a lens group LN having a negative refractive power, and a negative refraction. Consists of the final lens group with power,
When scaling or focusing, the distance between adjacent lens groups changes,
A zoom lens characterized by satisfying the following conditional expressions.
-1.20 ≤ f1 / fpt ≤ -0.05 ... (1)
0.05 ≤ fpMax / fw ≤ 1.25 ... (2)
However,
f1: Focal length of the first lens group fpt: Focal length of the intermediate group at infinity focusing at the telephoto end fpMax: Of the lens group having the strongest positive refractive power among the lens groups included in the intermediate group. Focal length fw: Focal length at infinity focusing at the wide-angle end of the zoom lens The zoom lens according to claim 1, which satisfies the following conditional expression.
-3.00 ≤ f1 / fw ≤ -1.00 ... (3) The zoom lens according to claim 1 or 2, which satisfies the following conditional expression.
-1.50 ≤ fn1 / ft ≤ -0.05 ... (4)
However,
fn1: Focal length of the lens group LN ft: Focal length at infinity focusing at the telephoto end of the zoom lens The zoom lens according to any one of claims 1 to 3, which satisfies the following conditional expression.
0.05 ≤ frt / ft ≤ 1.50 ... (5)
However,
frt: Combined focal length from the intermediate group to the final lens group at the telephoto end at infinity focus ft: Focal length at the telephoto end of the zoom lens at infinity focus The zoom lens according to any one of claims 1 to 4, which satisfies the following conditional expression.
-1.50 ≤ fn12 / ft ≤ -0.05 ... (6)
However,
fn12: Combined focal length from the lens group LN at the telephoto end to the final lens group ft: Focal length at the telephoto end of the zoom lens at infinity focusing The zoom lens according to any one of claims 1 to 5, which satisfies the following conditional expression.
1.00 ≤ βn1 ≤ 5.00 ... (7)
However,
βn1: Lateral magnification of the lens group LN at infinity focusing at the wide-angle end The zoom lens according to any one of claims 1 to 6, which satisfies the following conditional expression.
1.00 ≤ βn12 ≤ 5.00 ... (8)
However,
βn12: Combined lateral magnification from the lens group LN to the final lens group at infinity focusing at the wide-angle end The zoom lens according to any one of claims 1 to 7, wherein the lens group LN is moved in the optical axis direction to focus on a nearby object from infinity and satisfy the following conditional expression.
1.0 ≦ | {1- (βn1 × βn1)} × (βn2 × βn2) | ≦ 15.0 ... (9)
However,
βn1: Lateral magnification of the lens group LN at infinity focus at the wide-angle end βn2: Lateral magnification of the final lens group at infinity focus at the wide-angle end The zoom lens according to any one of claims 1 to 8, which satisfies the following conditional expression.
1.00 ≤ | CrG1r / fw | ... (10)
However,
CrG1r: Radius of curvature of the surface on the image side of the first lens group The zoom lens according to any one of claims 1 to 9, which satisfies the following conditional expression.
0.65 ≤ (fw x tanω) / BFw ≤ 2.30 ... (11)
However,
ω: Half angle of view at infinity focusing at the wide-angle end of the zoom lens BFw: Air equivalent length on the optical axis from the most image-side surface to the image plane at the wide-angle end of the zoom lens at infinity focusing Among the lens groups included in the intermediate group, the lens group having the strongest positive refractive power has at least one lens LpMp having a positive refractive power, and claims 1 to claim satisfy the following conditional expression. The zoom lens according to any one of 10.
45.0 ≤ νdLpMp ≤ 98.0 ... (12)
However,
νdLpMp: Abbe number in the d line of the lens LpMp The zoom lens according to any one of claims 1 to 11, wherein the first lens group has at least one lens L1p having a positive refractive power and satisfies the following conditional expression.
20.0 ≤ νdL1p ≤ 50.0 ... (13)
However,
νdL1p: Abbe number in the d line of the lens L1p The zoom lens according to any one of claims 1 to 12, wherein the first lens group has at least one lens L1p having a positive refractive power and satisfies the following conditional expression.
1.70 ≤ NdL1p ≤ 2.20 ... (14)
However,
NdL1p: Refractive index of the lens L1p on the d line The zoom lens according to any one of claims 1 to 13, which has a lens LnL having a negative refractive power on the most image side of the final lens group and satisfies the following conditional expression.
-3.00 ≤ fLnL / ft ≤ -0.05 ... (15)
However,
fLnL: Focal length of the lens LnL ft: Focal length at infinity focusing at the telephoto end of the zoom lens The zoom lens according to any one of claims 1 to 14, which satisfies the following conditional expression.
| BFt-BFw | / TLw ≤ 0.30 ... (16)
However,
BFw: Air equivalent length on the optical axis from the most image-side surface to the image plane at the wide-angle end of the zoom lens at infinity BFt: Most image-side at infinity-focused at the telephoto end of the zoom lens Air equivalent length on the optical axis from the plane to the image plane TLw: Optical total length at infinity focusing at the wide-angle end of the zoom lens The zoom lens according to any one of claims 1 to 15, and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal on the image side of the zoom lens. A featured image sensor.

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