JP6453041B2 - Zoom lens and imaging device - Google Patents

Description

  The present invention relates to a zoom lens suitable for a digital camera, a video camera, and the like, and an image pickup apparatus including the zoom lens.

  Conventionally, lenses for single-lens reflex cameras in particular have adopted a configuration that facilitates ensuring back focus by arranging a positive lens group behind the optical system in order to ensure a long flange back with respect to the focal length. There were a lot of things. However, in recent years, there has been an increase in cases where it is not necessary to ensure a long flange back due to the progress of miniaturization of camera bodies and the spread of digital cameras. Accordingly, zoom lenses with a relatively short back focus have been proposed so that they can be mounted on small cameras (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 3445025 Japanese Patent No. 3186388 JP 2007-286548 A

  Since digital cameras can also shoot moving images, high-speed autofocus processing that supports moving image shooting is desired. In autofocus, first, a part of lens groups (focus group) are vibrated at high speed in the optical axis direction (wobbling) to create a non-focus state → a focus state → a non-focus state. Then, a signal component in a specific frequency band in a partial image region is detected from the output signal of the image sensor, the optimum position of the focus group that is in focus is obtained, and the focus group is moved to the optimum position. In particular, in moving image shooting, it is required to continuously repeat these series of operations at a high speed.

  In particular, when wobbling is introduced, the size of the image corresponding to the subject changes during wobbling. This is mainly due to the change in the focal length of the entire optical system due to the movement of the focus group in the optical axis direction, and when the change in shooting magnification due to the change in the angle of view during wobbling is large. It will cause a sense of incongruity. In order to reduce this uncomfortable feeling, it is known that focusing may be performed with a lens group behind the diaphragm. In addition, in order to perform wobbling, the focus group is required to be as small and light as possible so that the focus group can be driven at high speed.

  Also, during moving image shooting, the orientation of the camera is changed in accordance with the movement of the subject, and the photographer often needs to move, so image blurring is likely to occur. For this reason, it is preferable that the photographic lens is provided with an anti-vibration group that performs anti-vibration correction. Even in the case of providing an anti-vibration group, in order to perform effective anti-vibration correction, the anti-vibration group is required to be as small and light as possible so that the anti-vibration group can be driven at high speed. .

  Conventionally, in an imaging sensor that receives an optical image and converts it into an electrical image signal, there is a limitation for efficiently capturing incident light with an on-chip microlens or the like. It has been desired to ensure the telecentricity of the incident light beam to the image sensor by increasing it to a certain value or more.

  However, recent imaging sensors have improved aperture ratios and advances in design flexibility of on-chip microlenses, and there are fewer restrictions on the exit pupil required on the photographic lens side. For this reason, in conventional photographic lenses, a positive lens is placed behind the optical system to ensure telecentricity. However, in recent years, this has become unnecessary, and a negative lens is placed behind the optical system to capture images. Even if the light beam is obliquely incident on the sensor, peripheral light reduction (shading) due to a pupil mismatch with the on-chip microlens has become inconspicuous. Thus, in the present situation where it is not always necessary to ensure the telecentricity of the incident light beam to the image sensor, the oblique incidence of the light beam to the image sensor is advantageous for downsizing the photographing lens. In addition, due to recent advances and improvements in software and camera systems, distortion aberration is large to some extent, and it has become possible to correct even conspicuous ones by image processing.

  However, it is difficult to say that the conventional zoom lens has been sufficiently reduced in size in accordance with the actual progress of downsizing of the camera. In addition, despite the widespread use of digital cameras that can shoot moving images, the zoom and anti-vibration groups are sufficiently small and lightweight, and a zoom lens is provided that enables good moving image shooting. It's hard to say.

  For example, Patent Document 1 discloses a standard zoom lens including a negative, positive, and negative four-group lens in order from the object side. In this zoom lens, since the relative power of the second lens group with respect to the third lens group is weak, it is necessary to ensure a sufficient amount of movement of the second lens group in order to increase the zoom ratio. The total length of is longer.

  The standard zoom lens disclosed in Patent Document 2 has a compact configuration of the optical system itself. However, this zoom lens is suitable for a film camera, and neither a focus group nor an image stabilization group corresponding to moving image shooting is provided. Further, since the power of the focus group is strong, the field curvature variation greatly occurs according to each object distance, and it is difficult to say that various aberrations are sufficiently corrected.

  In the standard zoom lens disclosed in Patent Document 3, the focal length of the fourth lens group with respect to the effective focal length of the entire optical system is long, so that the total length of the optical system is long, and a small-sized imaging device that has recently become widespread It is unsuitable for the lens.

  The present invention provides a compact, high-performance zoom lens that suppresses a change in photographing magnification due to a change in angle of view during wobbling and enables high-speed and good focusing in order to solve the above-described problems caused by the prior art. The purpose is to do. It is another object of the present invention to provide a compact and high-performance zoom lens having a small and lightweight vibration-proof group. In addition, an object of the present invention is to provide an imaging apparatus including a small, high-performance zoom lens.

In order to solve the above-described problems and achieve the object, a zoom lens according to the present invention includes a first lens group having a negative refractive power and a second lens having a positive refractive power, which are arranged in order from the object side. A group, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power, so that the interval between the first lens group and the second lens group is narrowed. By moving the first lens group, the second lens group, the third lens group, and the fourth lens group along the optical axis, zooming from the wide-angle end to the telephoto end is performed, and the third lens By moving the group along the optical axis toward the object side, focusing from the infinitely focused state to the closest focus state is performed, and the following conditional expression is satisfied.
(1) 0.330 ≦ f2 / f3 ≦ 0.650
(2) 0.45 ≦ α3T ≦ 0.58
Where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and α3T is the vertical magnification at the telephoto end of the third lens group.

  According to the present invention, it is possible to provide a small, high-performance zoom lens that suppresses a change in photographing magnification due to a change in the angle of view during wobbling and enables good focusing at high speed.

  Furthermore, in the zoom lens according to the present invention, in the above invention, the second lens group and the fourth lens group have trajectories having the same shape so that the movement amounts are equal when zooming from the wide-angle end to the telephoto end. It is characterized by moving by.

  According to the present invention, the second lens group and the fourth lens group can be easily integrated (unitized) using a lens frame or the like, the zoom lens assembly process can be simplified, and the lens barrel. Simplification of the structure can be achieved.

ただし、ｆ４は前記第４レンズ群の焦点距離、ｆｗは光学系全系の広角端における焦点距離、ｆｔは光学系全系の望遠端における焦点距離を示す。 Furthermore, the zoom lens according to the present invention is characterized in that, in the above invention, the following conditional expression is satisfied.

Here, f4 is the focal length of the fourth lens group, fw is the focal length at the wide angle end of the entire optical system, and ft is the focal length at the telephoto end of the entire optical system.

  According to the present invention, the overall length of the optical system can be shortened. In addition, by maintaining an appropriate exit pupil distance, it is possible to prevent a decrease in peripheral light amount and to form a clear image.

Further, in the zoom lens according to the present invention, in the above invention, the third lens group includes a single lens element and has a meniscus shape with a concave toward the object side. It is characterized by satisfying.
(4) 1.10 ≦ ra3 / rb3 ≦ 5.00
Here, ra3 represents the radius of curvature of the most object side surface of the third lens group, and rb3 represents the radius of curvature of the most image side surface of the third lens group.

  According to the present invention, the third lens group, which is a focus group, is reduced in size and weight, and the focus stroke is reduced, so that the change in photographing magnification due to the change in the angle of view during wobbling is suppressed. Enable. In addition, the entire optical system can be reduced in size.

ただし、ｆｖは前記防振群の焦点距離、ｆｗは光学系全系の広角端における焦点距離、ｆｔは光学系全系の望遠端における焦点距離を示す。 Furthermore, the zoom lens according to the present invention has the image stabilization group consisting of a single lens element in which the second lens group performs camera shake correction by moving the second lens group in a direction substantially perpendicular to the optical axis. And satisfying the following conditional expression.

Where fv is the focal length of the image stabilizing group, fw is the focal length at the wide angle end of the entire optical system, and ft is the focal length at the telephoto end of the entire optical system.

  According to the present invention, it is possible to provide a small and high-performance zoom lens including a small and lightweight vibration-proof group.

  An imaging apparatus according to the present invention includes the zoom lens and an imaging 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 an imaging device including a small and high-performance zoom lens.

  According to the present invention, there is an effect that it is possible to provide a small and high-performance zoom lens that suppresses a change in photographing magnification due to a change in angle of view during wobbling and enables high-speed and good focusing. Furthermore, there is an effect that it is possible to provide a small and high-performance zoom lens having a small and light vibration-proof group. In addition, there is an effect that it is possible to provide an imaging apparatus including a small and high-performance zoom lens.

FIG. 3 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to Example 1; FIG. 3 is a longitudinal aberration diagram of the zoom lens according to Example 1; FIG. 3 is a lateral aberration diagram at the telephoto end of the zoom lens according to Example 1; FIG. 6 is a cross-sectional view along the optical axis showing the configuration of a zoom lens according to Example 2; FIG. 6 is a longitudinal aberration diagram of the zoom lens according to Example 2; FIG. 6 is a lateral aberration diagram at a telephoto end of a zoom lens according to Example 2; FIG. 6 is a cross-sectional view along the optical axis showing the configuration of a zoom lens according to Example 3; FIG. 6 is a longitudinal aberration diagram of the zoom lens according to Example 3; FIG. 10 is a lateral aberration diagram at a telephoto end of a zoom lens according to Example 3; FIG. 6 is a cross-sectional view along the optical axis showing the configuration of a zoom lens according to Example 4; FIG. 6 is a longitudinal aberration diagram of a zoom lens according to Example 4; FIG. 10 is a lateral aberration diagram at a telephoto end of a zoom lens according to Example 4; FIG. 10 is a cross-sectional view along the optical axis showing the configuration of a zoom lens according to Example 5; FIG. 6 is a longitudinal aberration diagram of a zoom lens according to Example 5; FIG. 10 is a lateral aberration diagram at a telephoto end of a zoom lens according to Example 5; FIG. 10 is a cross-sectional view along the optical axis showing the configuration of a zoom lens according to Example 6; FIG. 10 is a longitudinal aberration diagram of a zoom lens according to Example 6; FIG. 10 is a lateral aberration diagram at the telephoto end of a zoom lens according to Example 6; It is a figure which shows one application example of the imaging device provided with the zoom lens concerning this invention.

  Hereinafter, preferred embodiments of a zoom lens and an imaging apparatus according to the present invention will be described in detail.

  The zoom lens according to the present invention includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side. And a fourth lens group having negative refractive power. Then, by moving the first lens group, the second lens group, the third lens group, and the fourth lens group along the optical axis so that the distance between the first lens group and the second lens group is narrowed. The zooming is performed from the wide-angle end to the telephoto end, and the third lens unit is moved along the optical axis toward the object side to perform focusing from the infinitely focused state to the closest focus state.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a compact and high-performance zoom lens that suppresses a change in photographing magnification due to a change in angle of view during wobbling and enables high-speed and good focusing (first object). . In order to achieve this object, the zoom lens according to the present invention has the following features.

  In the zoom lens according to the present invention, the third lens group as the focus group is disposed on the image side of the second lens group. Since the second lens group has a positive refractive power, the aperture of the third lens group disposed at the position where the beam diameter is reduced by the second lens group (image side of the second lens group) is reduced. It becomes possible to do. For this reason, the focus group can be reduced in size and weight, and high-speed focusing becomes possible. In addition, it is possible to reduce the diameter of the lens barrel.

  The aperture stop (optical stop) is generally preferably arranged between the object side of the second lens group and the image side of the third lens group for the purpose of cutting the light beams before and after the aperture stop. However, in the present invention, since the third lens group is the focus group, it is not preferable to configure the aperture stop so as to move together with the third lens group in order to execute high-speed focusing. Therefore, the zoom lens according to the present invention employs a configuration in which the aperture stop is disposed in the second lens group and moves together with the second lens group at the time of zooming.

Furthermore, in the zoom lens according to the present invention, when the focal length of the second lens group is f2, the focal length of the third lens group is f3, and the vertical magnification at the telephoto end of the third lens group is α3T, the following conditional expression Is preferably satisfied.
(1) 0.330 ≦ f2 / f3 ≦ 0.650
(2) 0.45 ≦ α3T ≦ 0.58

  By satisfying the conditional expressions (1) and (2), a small and high-performance zoom lens that suppresses the change in photographing magnification due to the change in the angle of view during wobbling and enables good focusing at high speed is realized. be able to.

  Conditional expression (1) defines the ratio between the focal length of the second lens group and the focal length of the third lens group. By satisfying conditional expression (1), it is possible to achieve both shortening of the total length of the optical system and improvement of optical performance.

  If the lower limit of conditional expression (1) is not reached, the relative power of the second lens group becomes too strong, and various aberrations that occur in the second lens group increase, making correction difficult. . On the other hand, if the upper limit in conditional expression (1) is exceeded, the relative power of the second lens group becomes too weak, so that a sufficient amount of movement of the second lens group is necessary to increase the zoom ratio. As a result, the entire length of the optical system is increased.

In addition, the said conditional expression (1) can anticipate a more preferable effect, if the range shown next is satisfied.
(1a) 0.335 ≦ f2 / f3 ≦ 0.600
By satisfying the range defined by the conditional expression (1a), it becomes easy to achieve both shortening of the total length of the optical system and improvement of optical performance.

Furthermore, when the conditional expression (1a) satisfies the following range, a further preferable effect can be expected.
(1b) 0.340 ≦ f2 / f3 ≦ 0.550
By satisfying the range defined by the conditional expression (1b), it becomes easier to achieve both shortening of the total length of the optical system and improvement of the optical performance.

  Conditional expression (2) defines the vertical magnification at the telephoto end of the third lens group. By satisfying conditional expression (2), it is possible to reduce the total length of the optical system by reducing the focus stroke of the third lens group, which is the focus group, and to change the photographing magnification due to the change in the angle of view during wobbling. Suppresses and enables good focusing at high speed.

  If the lower limit of conditional expression (2) is not reached, the power of the third lens group becomes too weak, the focus stroke from the infinite focus state to the closest focus state becomes large, and the entire length of the optical system is extended. Because it causes, it is not preferable. In this case, it becomes difficult to suppress a change in photographing magnification due to a change in the angle of view during wobbling and to perform good focusing at high speed. On the other hand, if the upper limit in conditional expression (2) is exceeded, the power of the third lens group becomes too strong, so the sensitivity of the third lens group to movement on the optical axis increases, and the third lens group is driven. Control is difficult, and the field curvature variation corresponding to each object distance increases, which is not preferable.

  Furthermore, in the zoom lens according to the present invention, it is preferable that the second lens group and the fourth lens group move along a locus having the same shape so that the amount of movement becomes equal when zooming from the wide-angle end to the telephoto end. .

  If the second lens group and the fourth lens group move along the locus of the same shape at the time of zooming, the second lens group and the fourth lens group may be integrated (unitized) using a lens frame or the like. it can. With this integrated structure, the cam structure that controls the zooming action in the lens barrel can be simplified, and the maximum diameter of the lens barrel can be reduced. In addition, the relative decentration of the second lens group and the fourth lens group that can occur during zooming can be suppressed to a small level, and deterioration of optical performance caused by manufacturing errors during assembly can be suppressed. Become. If the second lens group and the fourth lens group are integrated with a lens frame or the like, the assembly process of the zoom lens can be simplified, and the position of each lens group for suppressing the occurrence of manufacturing errors of the zoom lens. Adjustment and the like are also facilitated, and the manufacturing cost of the zoom lens can be reduced. The structure of the lens barrel can be simplified.

Furthermore, in the zoom lens according to the present invention, when the focal length of the fourth lens unit is f4, the focal length at the wide-angle end of the entire optical system is fw, and the focal length at the telephoto end of the entire optical system is ft, It is preferable to satisfy the following conditional expression.

  Conditional expression (3) defines the focal length of the fourth lens group with respect to the effective focal length of the entire optical system. By satisfying conditional expression (3), the total length of the optical system can be shortened. In addition, by maintaining an appropriate exit pupil distance, it is possible to prevent a decrease in peripheral light amount and to form a clear image.

  If the lower limit of conditional expression (3) is not reached, the negative power of the fourth lens group becomes too weak to sufficiently increase the lateral magnification, and the optical system from the first lens group to the third lens group. As a result, the overall length of the optical system is extended. On the other hand, if the upper limit in conditional expression (3) is exceeded, the negative power of the fourth lens group becomes too strong, so the exit pupil distance is shortened, and the incident light on the image pickup device such as a CCD disposed on the image plane Is obliquely incident, and this causes a decrease in the amount of light due to an imbalance of the pupils in the peripheral area, which is not preferable.

この条件式（３ａ）で規定する範囲を満足することにより、光学系全長の短縮と良好な光学性能の維持とを両立しやすくなる。 In addition, if the said conditional expression (3) satisfies the range shown next, a more preferable effect can be anticipated.

By satisfying the range defined by the conditional expression (3a), it becomes easy to achieve both shortening of the total length of the optical system and maintaining good optical performance.

この条件式（３ｂ）で規定する範囲を満足することにより、光学系全長の短縮と良好な光学性能の維持との両立がより容易になる。 Furthermore, if the said conditional expression (3a) satisfies the range shown next, the further preferable effect can be anticipated.

By satisfying the range defined by this conditional expression (3b), it becomes easier to reduce the overall length of the optical system and maintain good optical performance.

  Here, in the zoom lens according to the present invention, it is preferable that the third lens group as the focus group is constituted by a single lens element. The single lens element includes a single polished lens, an aspheric lens, a composite aspheric lens, and a cemented lens, and does not include, for example, two positive and negative lenses that have an air layer and are not bonded to each other. In this way, the weight of the focus group can be further reduced, the load of the autofocus mechanism that drives the focus group can be reduced, and faster focusing can be performed. In addition, it is possible to reduce power consumption for focusing. In addition, by configuring the third lens group as a single lens element and forming a meniscus shape with a concave toward the object side, it is possible to suppress fluctuations in field curvature during focusing.

In the zoom lens according to the present invention, on the premise that the third lens group is composed of a single lens element and has a meniscus shape with the concave facing the object side, the most object side surface of the third lens group It is preferable that the following conditional expression is satisfied, where ra3 is the radius of curvature and rab is the radius of curvature of the side of the most image surface of the third lens unit.
(4) 1.10 ≦ ra3 / rb3 ≦ 5.00

  Conditional expression (4) defines the ratio between the radius of curvature of the most object side surface of the third lens group and the radius of curvature of the most image side surface of the third lens group. By satisfying conditional expression (4), the third lens group, which is the focus group, can be reduced in size and weight, and the focus stroke can be reduced to suppress a change in photographing magnification due to a change in the angle of view during wobbling. Enables fast and good focusing. Moreover, the optical performance during focusing can be improved by reducing the size of the entire optical system.

  If the lower limit of conditional expression (4) is not reached, the power of the third lens group becomes too weak, the focus stroke from the infinite focus state to the closest focus state becomes large, and the entire length of the optical system is extended. Because it causes, it is not preferable. In this case, it becomes difficult to suppress a change in photographing magnification due to a change in the angle of view during wobbling and to perform good focusing at high speed. On the other hand, if the upper limit in conditional expression (4) is exceeded, the power of the third lens group becomes too strong and the sensitivity of the third lens group to the movement on the optical axis increases, and the third lens group is driven. Control is difficult, and the field curvature variation corresponding to each object distance increases, which is not preferable.

In addition, if the said conditional expression (4) satisfies the range shown next, a more preferable effect can be anticipated.
(4a) 1.20 ≦ ra3 / rb3 ≦ 4.00
By satisfying the range defined by the conditional expression (4a), it becomes easy to achieve both shortening of the total length of the optical system and good focusing.

Furthermore, when the conditional expression (4a) satisfies the following range, a further preferable effect can be expected.
(4b) 1.30 ≦ ra3 / rb3 ≦ 3.00
By satisfying the range defined by the conditional expression (4b), it becomes easier to achieve both shortening of the total length of the optical system and good focusing.

  Another object of the present invention is to provide a small and high-performance zoom lens having a small and light vibration-proof group (second object). In order to achieve this object, the zoom lens according to the present invention has the following features in addition to the above features.

  In the zoom lens according to the present invention, the second lens group has an anti-vibration group. The image stabilizing group is moved in a direction substantially perpendicular to the optical axis to perform camera shake correction. Here, the anti-vibration group is preferably composed of a single lens element. The single lens element includes a single polished lens, an aspheric lens, a composite aspheric lens, and a cemented lens, and does not include, for example, two positive and negative lenses that have an air layer and are not bonded to each other. By doing in this way, the vibration proof group can be reduced in size and weight. The downsizing of the anti-vibration group promotes a reduction in the diameter of the lens barrel. Further, the weight reduction of the vibration proof group can reduce the load of the vibration proof mechanism that drives the vibration proof group, enables quick camera shake correction, and can reduce the power consumption of the vibration proof mechanism.

Furthermore, in the zoom lens according to the present invention, on the assumption that the second lens group has an anti-vibration group consisting of a single lens element, the focal length of the anti-vibration group is fv, and the focal length at the wide-angle end of the entire optical system. Is fw, and the focal length at the telephoto end of the entire optical system is ft, it is preferable that the following conditional expression is satisfied.

  Conditional expression (5) defines the focal length of the image stabilizing group with respect to the effective focal length of the entire optical system. By satisfying conditional expression (5), it is possible to realize a small and high-performance zoom lens having a small and light vibration-proof group.

  If the lower limit of conditional expression (5) is not reached, the power of the anti-vibration group becomes too strong, and various aberrations (e.g. decentration coma and decentering astigmatism) occur during camera shake correction, making correction difficult. become. In this case, in order to perform aberration correction, the number of lenses constituting the image stabilization group must be increased, and as a result, it is difficult to reduce the size and weight of the image stabilization group. On the other hand, if the upper limit is exceeded in the conditional expression (5), the power of the image stabilization group becomes too weak, so the amount of movement of the image stabilization group at the time of camera shake correction increases, and high-speed control of the image stabilization group becomes difficult. Good camera shake correction becomes difficult. In addition, the effective optical diameter increases and it is difficult to reduce the diameter of the lens barrel.

この条件式（５ａ）で規定する範囲を満足することにより、良好な光学性能を維持したまま、防振群のより小型、軽量化、光学有効径のより小径化を図ることができる。 In addition, the said conditional expression (5) can anticipate a more preferable effect, if the range shown next is satisfied.

By satisfying the range defined by the conditional expression (5a), it is possible to reduce the size and weight of the vibration-proof group and reduce the effective optical diameter while maintaining good optical performance.

この条件式（５ｂ）で規定する範囲を満足することにより、良好な光学性能を維持したまま、防振群の一層の小型、軽量化、光学有効径の一層の小径化を図ることができる。 Furthermore, when the conditional expression (5a) satisfies the following range, a further preferable effect can be expected.

By satisfying the range defined by the conditional expression (5b), it is possible to further reduce the size and weight of the vibration isolation group and further reduce the effective optical diameter while maintaining good optical performance.

  As described above, the zoom lens according to the present invention has the above-described configuration, thereby shortening the overall length of the optical system and suppressing the amount of movement of the focus group during focusing, and taking magnification due to field angle fluctuation during wobbling. Can be suppressed. In addition, the focus group can be reduced in size and weight, and good focusing can be performed at high speed. Correction of various aberrations during focusing is also improved. Furthermore, by reducing the size and weight of the vibration-proof group, it is possible to maintain good optical performance even during camera shake correction. The diameter of the optical system can also be reduced.

  Furthermore, an object of the present invention is to provide an image pickup apparatus including a small, high-performance zoom lens (third object). In order to achieve this object, an imaging apparatus may be configured by including a zoom lens having the above-described configuration and an imaging element that converts an optical image formed by the zoom lens into an electrical signal. By doing so, it is possible to realize an imaging apparatus suitable for moving image shooting, which includes a small and high-performance zoom lens.

  Embodiments of the zoom lens according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by the following examples.

FIG. 1 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the first embodiment. The zoom lens includes a first lens group G ₁₁ having negative refractive power, a second lens group G ₁₂ having positive refractive power, and a third lens group having positive refractive power in order from the object side (not shown). G ₁₃ and a fourth lens group G ₁₄ having negative refractive power are arranged. Between the fourth lens group G ₁₄ and an image plane IMG, a cover glass CG is disposed.

The first lens group G ₁₁ is constituted in order from the object side, a negative lens L _111, a negative lens L _112, a positive lens L _113, is the arrangement.

The second lens group G ₁₂ includes, in order from the object side, a positive lens L _121, and the aperture stop STP defines a predetermined diameter, a positive lens L _122, a negative lens L _123, a positive lens L _124, is arranged Configured. Aspherical surfaces are formed on both surfaces of each of the positive lens L ₁₂₁ and the positive lens L ₁₂₄ . Further, the positive lens L ₁₂₂ and the negative lens L ₁₂₃ are cemented.

The third lens group G ₁₃ is constituted by a meniscus lens L ₁₃₁ having a positive refractive power with a concave surface on the object side. On both surfaces of the meniscus lens L _131, aspheric surface is formed.

The fourth lens group G ₁₄ is constituted by a negative lens L _141.

In this zoom lens, during zooming from the wide angle end to the telephoto end, the second lens group G ₁₂ , the third lens group G ₁₃ , and the fourth lens group G ₁₄ are moved along the optical axis from the image plane IMG side to the object side. Move to. At this time, the second lens group G ₁₂ and the fourth lens group G _14, which moves along a locus of the same shape as the amount of movement is equal. The first lens group G ₁₁ moves from the object side to the image plane IMG side along the optical axis from the wide-angle end to the vicinity of the intermediate focal position, and from the vicinity of the intermediate focal position to the telephoto end along the optical axis. Move from the surface IMG side to the object side. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group G ₁₁ and the second lens group G ₁₂ becomes narrower.

In this zoom lens, by moving from the image plane IMG side to the object side along the third lens group G ₁₃ to the optical axis to perform focusing from an infinity in-focus state to a closest distance in-focus state. Moreover, not play a function as a vibration-proof group VC ₁ positive lens L ₁₂₄ in the second lens group G _12,
Camera shake correction is performed by moving the image stabilizing group VC ₁ in a direction substantially perpendicular to the optical axis.

  Various numerical data related to the zoom lens according to Example 1 will be described below.

F-number = 3.61 (wide-angle end) to 5.00 (intermediate focus position) to 5.77 (telephoto end)
Focal length of the entire zoom lens = 28.91 (fw: wide-angle end) to 44.97 (intermediate focal position) to 67.84 (ft: telephoto end)
Half angle of view (ω) = 37.95 (wide-angle end) to 25.86 (intermediate focus position) to 17.64 (telephoto end)

(Lens data)
r ₁ = 50.302
d ₁ = 1.500 nd ₁ = 1.8061 νd ₁ = 40.73
r ₂ = 18.864
d ₂ = 9.473
r ₃ = -52.775
d ₃ = 1.200 nd ₂ = 1.4875 νd ₂ = 70.44
r ₄ = 150.638
d ₄ = 0.200
r ₅ = 35.609
d ₅ = 3.504 nd ₃ = 1.8467 νd ₃ = 23.78
r ₆ = 89.638
d ₆ = D (6) (variable)
r ₇ = 19.352 (aspherical surface)
d ₇ = 3.601 nd ₄ = 1.4971 νd ₄ = 81.56
r ₈ = -158.106 (aspherical surface)
d ₈ = 2.403
r ₉ = ∞ (aperture stop)
d ₉ = 2.446
r ₁₀ = 13.927
d ₁₀ = 2.867 nd ₅ = 1.4970 νd ₅ = 81.61
r ₁₁ = 30.65
d ₁₁ = 1.000 nd ₆ = 1.8061 νd ₆ = 33.27
r ₁₂ = 12.258
d ₁₂ = 2.931
r ₁₃ = 35.293 (aspherical surface)
d ₁₃ = 2.288 nd ₇ = 1.5533 νd ₇ = 71.68
r ₁₄ = -211.117 (aspherical surface)
d ₁₄ = D (14) (variable)
r ₁₅ = -19.95 (aspherical surface)
d ₁₅ = 5.000 nd ₈ = 1.5312 νd ₈ = 56.04
r ₁₆ = -15.061 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = −31.299
d ₁₇ = 1.200 nd ₉ = 1.5168 νd ₉ = 64.2
r ₁₈ = -1053.546
d ₁₈ = D (18) (variable)
r ₁₉ = ∞
d ₁₉ = 2.500 nd ₁₀ = 1.5168 νd ₁₀ = 64.2
r ₂₀ = ∞
d ₂₀ = 1.000
r ₂₁ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Seventh side)
k = 0,
A ₄ = -4.4730 × 10 ^-6 , A ₆ = 4.1460 × 10 ^-8 ,
A ₈ = -2.4742 × 10 ^-10 , A ₁₀ = -2.4518 × 10 ^-12
(8th page)
k = 0,
A ₄ = 1.4972 × 10 ⁻⁵ , A ₆ = −2.9593 × 10 ⁻⁸ ,
A ₈ = 3.5948 × 10 ⁻¹⁰ , A ₁₀ = −6.0553 × 10 ⁻¹²
(13th page)
k = 0,
A ₄ = 3.8722 × 10 ⁻⁵ , A ₆ = 2.5149 × 10 ⁻⁷ ,
A ₈ = -9.4360 × 10 ^-9 , A ₁₀ = -4.1945 × 10 ^-11
(14th page)
k = 0,
A ₄ = 4.0085 × 10 ⁻⁵ , A ₆ = 2.7375 × 10 ⁻⁷ ,
A ₈ = -9.2853 × 10 ⁻⁹ , A ₁₀ = −3.6388 × 10 ⁻¹¹
(15th page)
k = 0,
A ₄ = -6.9413 × 10 ^-5 , A ₆ = -1.2328 × 10 ^-6 ,
A ₈ = 1.1971 × 10 ^-8 , A ₁₀ = -1.7831 × 10 ^-10
(16th page)
k = 0,
A ₄ = -2.7565 × 10 ^-5 , A ₆ = -5.2901 × 10 ^-7 ,
A ₈ = 3.9643 × 10 ⁻⁹ , A ₁₀ = −4.5222 × 10 ⁻¹¹

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 24.838 10.040 2.500
D (14) 7.975 9.886 15.009
D (16) 9.573 7.663 2.540
D (18) 14.500 26.693 45.775

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₁₂₎ = 31.43
f3 (the focal length of the third lens group G ₁₃₎ = 84.98
f2 / f3 = 0.370

(Numerical value related to conditional expression (2))
Arufa3T (longitudinal magnification at the telephoto end of the third lens group G ₁₃₎ = 0.54

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₁₄₎ = - 62.21

(Numerical values related to conditional expression (4))
RA3 (curvature of the most object side surface of the third lens group G ₁₃ radius) = - 19.950
rb3 (curvature of the most image plane side surface of the third lens group G ₁₃ radius) = - 15.061
ra3 / rb3 = 1.32

(Numerical values related to conditional expression (5))
fv (focal length of anti-vibration group VC ₁ ) = 54.65

  FIG. 2 is a longitudinal aberration diagram of the zoom lens according to the first example. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 3 is a lateral aberration diagram of the zoom lens according to Example 1 at the telephoto end. In these figures, (a) indicates a basic state not performing image stabilization at the telephoto end, (b) is 0.260mm moved in a direction substantially perpendicular to the vibration-proof group VC ₁ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The amount of image decentering when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image decentering amount when the image stabilizing group VC ₁ is translated by 0.260 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  3 (a) and 3 (b), the upper stage shows lateral aberration at an image point of 70% of the maximum image height, the middle stage shows lateral aberration at an axial image point, and the lower stage shows -70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. It is also possible to take even greater than 0.3 ° of shake correction angle by applying the translation amount of vibration proof group VC ₁ at the wide angle end and the intermediate focal position at the telephoto end.

FIG. 4 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the second embodiment. The zoom lens includes a first lens group G ₂₁ having a negative refractive power, a second lens group G ₂₂ having a positive refractive power, and a third lens group having a positive refractive power in order from an object side (not shown). G ₂₃ and a fourth lens group G ₂₄ having negative refractive power are arranged. A cover glass CG is disposed between the fourth lens group G ₂₄ and the image plane IMG.

The first lens group G ₂₁ includes a negative lens L ₂₁₁ , a negative lens L _212, and a positive lens L ₂₁₃ arranged in order from the object side.

The second lens group G ₂₂ includes, in order from the object side, a positive lens L ₂₂₁ , an aperture stop STP that defines a predetermined aperture, a positive lens L ₂₂₂ , a negative lens L _223, and a positive lens L _224. Configured. Aspherical surfaces are formed on both surfaces of the positive lens L ₂₂₁ and the positive lens L ₂₂₄ , respectively.

The third lens group G ₂₃ is constituted by a meniscus lens L ₂₃₁ having a positive refractive power with a concave surface on the object side. Aspherical surfaces are formed on both sides of the meniscus lens _L231 .

The fourth lens group G ₂₄ is constituted by a negative lens L _241.

In this zoom lens, during zooming from the wide-angle end to the telephoto end, the second lens group G ₂₂ , the third lens group G ₂₃ , and the fourth lens group G ₂₄ are moved along the optical axis from the image plane IMG side to the object side. Move to. At this time, the second lens group G ₂₂ and the fourth lens group G ₂₄ move along the locus of the same shape so that the movement amounts are equal. The first lens group G ₂₁ moves from the object side to the image plane IMG side along the optical axis from the wide-angle end to the vicinity of the intermediate focal position, and from the vicinity of the intermediate focal position to the telephoto end along the optical axis. Move from the surface IMG side to the object side. At the time of zooming from the wide angle end to the telephoto end, the distance between the first lens group G ₂₁ and the second lens group G ₂₂ becomes narrower.

In this zoom lens, by moving from the image plane IMG side to the object side along the third lens group G ₂₃ to the optical axis to perform focusing from an infinity in-focus state to a closest distance in-focus state. Further, the positive lens L ₂₂₄ in the second lens group G ₂₂ has a function as the image stabilization group VC ₂ .
By moving to a direction substantially perpendicular to the optical axis of vibration-proof group VC _2, correcting the camera shake.

  Various numerical data related to the zoom lens according to Example 2 will be described below.

F-number = 3.61 (wide-angle end) to 5.00 (intermediate focus position) to 5.77 (telephoto end)
Focal length of the entire zoom lens = 28.89 (fw: wide angle end) to 45.00 (intermediate focal position) to 67.94 (ft: telephoto end)
Half angle of view (ω) = 37.94 (wide-angle end) to 25.87 (intermediate focus position) to 17.65 (telephoto end)

(Lens data)
r ₁ = 47.449
d ₁ = 1.500 nd ₁ = 1.9037 νd ₁ = 31.31
r ₂ = 20.38
d ₂ = 11.128
r ₃ = -52.534
d ₃ = 1.200 nd ₂ = 1.4875 νd ₂ = 70.44
r ₄ = 63.526
d ₄ = 0.245
r ₅ = 39.16
d ₅ = 3.721 nd ₃ = 1.8467 νd ₃ = 23.78
r ₆ = 223.17
d ₆ = D (6) (variable)
r ₇ = 23.687 (aspherical surface)
d ₇ = 2.995 nd ₄ = 1.6014 νd ₄ = 54.32
r ₈ = -1714.338 (aspherical surface)
d ₈ = 2.049
r ₉ = ∞ (aperture stop)
d ₉ = 2.007
r ₁₀ = 23.115
d ₁₀ = 4.369 nd ₅ = 1.4970 νd ₅ = 81.61
r ₁₁ = -24.965
d ₁₁ = 0.208
r ₁₂ = -49.803
d ₁₂ = 1.000 nd ₆ = 1.6427 νd ₆ = 35.68
r ₁₃ = 14.8
d ₁₃ = 2.928
r ₁₄ = 44.602 (aspherical surface)
d ₁₄ = 2.327 nd ₇ = 1.5312 νd ₇ = 56.04
r ₁₅ = -98.074 (aspherical surface)
d ₁₅ = D (15) (variable)
r ₁₆ = -20.062 (aspherical surface)
d ₁₆ = 4.944 nd ₈ = 1.4971 νd ₈ = 81.56
r ₁₇ = -15.227 (aspherical surface)
d ₁₇ = D (17) (variable)
r ₁₈ = -35.987
d ₁₈ = 1.200 nd ₉ = 1.5168 νd ₉ = 64.2
r ₁₉ = 942.382
d ₁₉ = D (19) (variable)
r ₂₀ = ∞
d ₂₀ = 2.500 nd ₁₀ = 1.5168 νd ₁₀ = 64.2
r ₂₁ = ∞
d ₂₁ = 1.000
r ₂₂ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Seventh side)
k = 0,
A ₄ = -1.2194 × 10 ^-5 , A ₆ = 1.3079 × 10 ^-8 ,
A ₈ = 4.9353 × 10 ⁻¹¹ , A ₁₀ = −1.1241 × 10 ⁻¹¹
(8th page)
k = 0,
A ₄ = 1.0663 × 10 ⁻⁵ , A ₆ = 1.0459 × 10 ⁻⁷ ,
A ₈ = -5.6358 × 10 ^-10 , A ₁₀ = -5.0390 × 10 ^-12
(14th page)
k = 0,
A ₄ = 2.5379 × 10 ⁻⁶ , A ₆ = 2.6115 × 10 ⁻⁷ ,
A ₈ = -8.8538 × 10 ^-9 , A ₁₀ = 6.1053 × 10 ^-12
(15th page)
k = 0,
A ₄ = 5.0189 × 10 ⁻⁶ , A ₆ = 1.6860 × 10 ⁻⁷ ,
A ₈ = −6.9209 × 10 ⁻⁹ , A ₁₀ = −3.77871 × 10 ⁻¹²
(16th page)
k = 0,
A ₄ = -5.8349 × 10 ^-5 , A ₆ = -1.2055 × 10 ^-6 ,
A ₈ = 1.3280 × 10 ⁻⁸ , A ₁₀ = −1.6328 × 10 ⁻¹⁰
(Seventeenth surface)
k = 0,
A ₄ = -2.1862 × 10 ⁻⁵ , A ₆ = −4.9740 × 10 ⁻⁷ ,
A ₈ = 3.9884 × 10 ⁻⁹ , A ₁₀ = −4.0365 × 10 ⁻¹¹

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 25.457 10.101 2.500
D (15) 7.942 10.534 17.165
D (17) 11.695 9.103 2.473
D (19) 14.584 27.178 47.029

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₂₂₎ = 33.06
f3 (the focal length of the third lens group G ₂₃₎ = 94.56
f2 / f3 = 0.350

(Numerical value related to conditional expression (2))
Arufa3T (longitudinal magnification at the telephoto end of the third lens group G ₂₃₎ = 0.57

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₂₄₎ = - 66.80

(Numerical values related to conditional expression (4))
RA3 (curvature of the most object side surface of the third lens group G ₂₃ radius) = - 20.062
rb3 (curvature of the most image plane side surface of the third lens group G ₂₃ radius) = - 15.227
ra3 / rb3 = 1.32

(Numerical values related to conditional expression (5))
fv (focal length of anti-vibration group VC ₂ ) = 57.80

  FIG. 5 is a longitudinal aberration diagram of the zoom lens according to Example 2. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 6 is a lateral aberration diagram at the telephoto end of the zoom lens according to Example 2. In these figures, (a) indicates a basic state not performing image stabilization at the telephoto end, (b) is 0.261mm moved in a direction substantially perpendicular to the vibration-proof group VC ₂ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The image decentering amount when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image decentering when the image stabilizing group VC ₂ is translated by 0.261 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  6 (a) and 6 (b), the upper row shows the lateral aberration at the image point of 70% of the maximum image height, the middle row shows the lateral aberration at the axial image point, and the lower row shows -70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. It is also possible to take even greater than 0.3 ° of shake correction angle by applying the translation amount of vibration proof group VC ₂ at the wide angle end and the intermediate focal position at the telephoto end.

FIG. 7 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the third embodiment. The zoom lens includes a first lens group G ₃₁ having a negative refractive power, a second lens group G ₃₂ having a positive refractive power, and a third lens group having a positive refractive power in order from an object side (not shown). G ₃₃ and a fourth lens group G ₃₄ having negative refractive power are arranged. Between the fourth lens group G ₃₄ and an image plane IMG, a cover glass CG is disposed.

The first lens group G ₃₁ includes a negative lens L ₃₁₁ , a negative lens L _312, and a positive lens L ₃₁₃ arranged in order from the object side.

The second lens group G ₃₂ includes, in order from the object side, a positive lens L ₃₂₁ , an aperture stop STP that defines a predetermined aperture, a positive lens L ₃₂₂ , a negative lens L _323, and a positive lens L _324. Configured. Aspherical surfaces are formed on both surfaces of the positive lens L ₃₂₁ and the positive lens L ₃₂₄ .

The third lens group G ₃₃ includes a meniscus lens L ₃₃₁ having a positive refractive power with a concave surface facing the object side. Aspheric surfaces are formed on both surfaces of the meniscus lens _L331 .

The fourth lens group G ₃₄ includes, in order from the object side and the negative lens L _341.

In this zoom lens, during zooming from the wide-angle end to the telephoto end, the second lens group G ₃₂ , the third lens group G ₃₃ , and the fourth lens group G ₃₄ are moved along the optical axis from the image plane IMG side to the object side. Move to. At this time, the second lens group G ₃₂ and the fourth lens group G ₃₄ move along the locus of the same shape so that the movement amounts are equal. The first lens group G ₃₁ moves from the object side to the image plane IMG side along the optical axis from the wide-angle end to the vicinity of the intermediate focal position, and from the vicinity of the intermediate focal position to the telephoto end along the optical axis. Move from the surface IMG side to the object side. At the time of zooming from the wide angle end to the telephoto end, the distance between the first lens group G ₃₁ and the second lens group G ₃₂ becomes narrower.

In this zoom lens, by moving from the image plane IMG side to the object side along the third lens group G ₃₃ to the optical axis to perform focusing from an infinity in-focus state to a closest distance in-focus state. In addition, the positive lens L ₃₂₄ in the second lens group G ₃₂ has a function as the image stabilization group VC ₃ .
Camera shake correction is performed by moving the image stabilizing group VC ₃ in a direction substantially perpendicular to the optical axis.

  Various numerical data relating to the zoom lens according to Example 3 will be described below.

F-number = 3.60 (wide-angle end) to 5.00 (intermediate focus position) to 5.74 (telephoto end)
Focal length of the entire zoom lens = 28.74 (fw: wide-angle end) to 45.00 (intermediate focal position) to 68.29 (ft: telephoto end)
Half angle of view (ω) = 36.96 (wide-angle end) to 25.67 (intermediate focus position) to 17.60 (telephoto end)

(Lens data)
r ₁ = 46.271
d ₁ = 1.600 nd ₁ = 1.9037 νd ₁ = 31.31
r ₂ = 20.339
d ₂ = 10.392
r ₃ = -49.106
d ₃ = 1.300 nd ₂ = 1.4875 νd ₂ = 70.44
r ₄ = 86.589
d ₄ = 0.300
r ₅ = 39.198
d ₅ = 4.226 nd ₃ = 1.8467 νd ₃ = 23.78
r ₆ = 176.208
d ₆ = D (6) (variable)
r ₇ = 23.121 (aspherical surface)
d ₇ = 3.431 nd ₄ = 1.5831 νd ₄ = 59.46
r ₈ = -1000.135 (aspherical surface)
d ₈ = 2.000
r ₉ = ∞ (aperture stop)
d ₉ = 2.033
r ₁₀ = 27.71
d ₁₀ = 4.522 nd ₅ = 1.4970 νd ₅ = 81.61
r ₁₁ = -27.252
d ₁₁ = 0.300
r ₁₂ = -53.003
d ₁₂ = 1.000 nd ₆ = 1.6200 νd ₆ = 36.3
r ₁₃ = 15.154
d ₁₃ = 2.905
r ₁₄ = 33.691 (aspherical surface)
d ₁₄ = 2.458 nd ₇ = 1.5312 νd ₇ = 56.04
r ₁₅ = -118.694 (aspherical surface)
d ₁₅ = D (15) (variable)
r ₁₆ = -21.678 (aspherical surface)
d ₁₆ = 5.000 nd ₈ = 1.4971 νd ₈ = 81.56
r ₁₇ = -15.726 (aspherical surface)
d ₁₇ = D (17) (variable)
r ₁₈ = -28.298
d ₁₈ = 1.200 nd ₉ = 1.5168 νd ₉ = 64.2
r ₁₉ = ∞
d ₁₉ = D (19) (variable)
r ₂₀ = ∞
d ₂₀ = 3.100 nd ₁₀ = 1.5168 νd ₁₀ = 64.2
r ₂₁ = ∞
d ₂₁ = 1.000
r ₂₂ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Seventh side)
k = 0,
A ₄ = -2.8212 × 10 ^-5 , A ₆ = -1.3282 × 10 ^-7 ,
A ₈ = -1.2666 × 10 ^-9 , A ₁₀ = -2.4856 × 10 ^-11
(8th page)
k = 0,
A ₄ = -1.0687 × 10 ^-5 , A ₆ = -3.0034 × 10 ^-8 ,
A ₈ = -3.2626 × 10 ^-9 , A ₁₀ = -6.2652 × 10 ^-12
(14th page)
k = 0,
A ₄ = 3.4983 × 10 ⁻⁶ , A ₆ = 5.7335 × 10 ⁻⁷ ,
A ₈ = -1.8786 × 10 ^-8 , A ₁₀ = 1.6241 × 10 ^-10
(15th page)
k = 0,
A ₄ = 7.7283 × 10 ⁻⁶ , A ₆ = 4.3102 × 10 ⁻⁷ ,
A ₈ = -1.4703 × 10 ^-8 , A ₁₀ = 1.2515 × 10 ^-10
(16th page)
k = 0,
A ₄ = -7.3930 × 10 ^-5 , A ₆ = -9.0938 × 10 ^-7 ,
A ₈ = 8.8174 × 10 ^-9 , A ₁₀ = -1.3741 × 10 ^-10
(Seventeenth surface)
k = 0,
A ₄ = -3.7003 × 10 ⁻⁵ , A ₆ = −3.22489 × 10 ⁻⁷ ,
A ₈ = 1.6947 × 10 ^-9 , A ₁₀ = -3.0847 × 10 ^-11

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 26.255 10.157 2.500
D (15) 7.908 9.929 16.010
D (17) 11.070 9.050 2.968
D (19) 13.001 24.682 43.501

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₃₂₎ = 32.72
f3 (the focal length of the third lens group G ₃₃₎ = 89.79
f2 / f3 = 0.364

(Numerical value related to conditional expression (2))
Arufa3T (longitudinal magnification at the telephoto end of the third lens group G ₃₃₎ = 0.58

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₃₄₎ = - 54.54

(Numerical values related to conditional expression (4))
ra3 (curvature radius of the third object group G _{33 on} the most object side surface) =-21.678
rb3 (curvature of the most image plane side surface of the third lens group G ₃₃ radius) = - 15.726
ra3 / rb3 = 1.38

(Numerical values related to conditional expression (5))
fv (focal length of anti-vibration group VC ₃ ) = 49.47

  FIG. 8 is a longitudinal aberration diagram of the zoom lens according to the third example. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 9 is a lateral aberration diagram of the zoom lens according to Example 3 at the telephoto end. In these figures, (a) indicates a basic state not performing image stabilization at the telephoto end, (b) is 0.227mm moved in a direction substantially perpendicular to the vibration-proof group VC ₃ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The image decentering amount when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image decentering amount when the anti-vibration group VC ₃ is translated by 0.227 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  9 (a) and 9 (b), the upper stage shows lateral aberration at an image point of 70% of the maximum image height, the middle stage shows lateral aberration at an axial image point, and the lower stage shows -70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. Further, by applying the parallel movement amount of the image stabilizing group VC ₃ at the telephoto end to the wide-angle end and the intermediate focus position state, the camera shake correction angle can be made larger than 0.3 °.

FIG. 10 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the fourth example. This zoom lens includes, in order from the object side (not shown), a first lens group G ₄₁ having a negative refractive power, a second lens group G ₄₂ having a positive refractive power, and a third lens group having a positive refractive power. G ₄₃ and a fourth lens group G ₄₄ having negative refractive power are arranged. Between the fourth lens group G ₄₄ and an image plane IMG, a cover glass CG is disposed.

The first lens group G ₄₁ is constituted in order from the object side, a negative lens L _411, a negative lens L _412, a positive lens L _413, is the arrangement.

The second lens group G ₄₂ includes, in order from the object side, a positive lens L _421, and the aperture stop STP defines a predetermined diameter, a positive lens L _422, a negative lens L _423, a positive lens L _424, is arranged Configured. Aspherical surfaces are formed on both surfaces of each of the positive lens L ₄₂₁ and the positive lens L ₄₂₄ . Further, the positive lens L ₄₂₂ and the negative lens L ₄₂₃ are cemented.

The third lens group G ₄₃ includes a negative lens L ₄₃₁ and a positive lens L ₄₃₂ arranged in this order from the object side. An aspheric surface is formed on the object side surface of the negative lens _L431 . The negative lens L ₄₃₁ and the positive lens L ₄₃₂ are cemented, and the third lens group G ₄₃ is configured as a meniscus lens having a concave surface facing the object side.

The fourth lens group _G44 includes a negative lens _L441 . Aspherical surfaces are formed on both surfaces of the negative lens _L441 .

In this zoom lens, the first lens group G ₄₁ , the second lens group G ₄₂ , the third lens group G ₄₃ , and the fourth lens group G ₄₄ are moved along the optical axis upon zooming from the wide-angle end to the telephoto end. Move from the image plane IMG side to the object side. At this time, the second lens group G ₄₂ and the fourth lens group G ₄₄ move along the locus of the same shape so that the movement amounts are equal. At the time of zooming from the wide angle end to the telephoto end, the distance between the first lens group G ₄₁ and the second lens group G ₄₂ becomes narrower.

In this zoom lens, by moving from the image plane IMG side to the object side along the third lens group G ₄₃ to the optical axis to perform focusing from an infinity in-focus state to a closest distance in-focus state. In addition, the positive lens L ₄₂₄ in the second lens group G ₄₂ has a function as the anti-vibration group VC ₄ .
By moving to a direction substantially perpendicular to the optical axis of vibration-proof group VC _4, perform image stabilization.

  Various numerical data relating to the zoom lens according to Example 4 will be described below.

F-number = 3.61 (wide-angle end) to 5.00 (intermediate focus position) to 5.77 (telephoto end)
The focal length of the entire zoom lens = 28.65 (fw: wide-angle end) to 45.13 (intermediate focal position) to 67.91 (ft: telephoto end)
Half angle of view (ω) = 38.08 (wide-angle end) to 25.77 (intermediate focus position) to 17.55 (telephoto end)

(Lens data)
r ₁ = 33.439
d ₁ = 1.250 nd ₁ = 2.0006 νd ₁ = 25.46
r ₂ = 19.271
d ₂ = 15.071
r ₃ = -191.993
d ₃ = 1.000 nd ₂ = 1.6385 νd ₂ = 55.45
r ₄ = 36.431
d ₄ = 0.200
r ₅ = 30.472
d ₅ = 3.348 nd ₃ = 1.9229 νd ₃ = 20.88
r ₆ = 79.717
d ₆ = D (6) (variable)
r ₇ = 18.589 (aspherical surface)
d ₇ = 3.419 nd ₄ = 1.4971 νd ₄ = 81.56
r ₈ = 42.688 (aspherical surface)
d ₈ = 2.000
r ₉ = ∞ (aperture stop)
d ₉ = 2.000
r ₁₀ = 26.31
d ₁₀ = 3.276 nd ₅ = 1.5891 νd ₅ = 61.25
r ₁₁ = -38.709
d ₁₁ = 1.000 nd ₆ = 1.8052 νd ₆ = 25.46
r ₁₂ = -321.77
d ₁₂ = 2.064
r ₁₃ = 41.823 (aspherical surface)
d ₁₃ = 1.353 nd ₇ = 1.4971 νd ₇ = 81.56
r ₁₄ = 70.511 (aspherical surface)
d ₁₄ = D (14) (variable)
r ₁₅ = -21.904 (aspherical surface)
d ₁₅ = 1.360 nd ₈ = 1.5927 νd ₈ = 35.45
r ₁₆ = -30.514
d ₁₆ = 5.000 nd ₉ = 1.4970 νd ₉ = 81.61
r ₁₇ = -12.782
d ₁₇ = D (17) (variable)
r ₁₈ = -14.153 (aspherical surface)
d ₁₈ = 0.700 nd ₁₀ = 1.6935 νd ₁₀ = 53.2
r ₁₉ = -53.381 (aspherical surface)
d ₁₉ = D (19) (variable)
r ₂₀ = ∞
d ₂₀ = 2.500 nd ₁₁ = 1.5168 νd ₁₁ = 64.2
r ₂₁ = ∞
d ₂₁ = 1.000
r ₂₂ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Seventh side)
k = 0,
A ₄ = -3.3876 × 10 ⁻⁶ , A ₆ = 2.5263 × 10 ⁻⁸ ,
A ₈ = -6.4547 × 10 ^-11 , A ₁₀ = 4.8843 × 10 ^-12
(8th page)
k = 0,
A ₄ = 3.1715 × 10 ⁻⁶ , A ₆ = 2.1038 × 10 ⁻⁸ ,
A ₈ = 3.9660 × 10 ⁻¹⁰ , A ₁₀ = 3.1935 × 10 ⁻¹²
(13th page)
k = 0,
A ₄ = 1.1415 × 10 ⁻⁵ , A ₆ = 9.6172 × 10 ⁻⁸ ,
A ₈ = 1.0105 × 10 ^-9 , A ₁₀ = -8.9091 × 10 ^-12
(14th page)
k = 0,
A ₄ = 1.3818 × 10 ⁻⁵ , A ₆ = 8.7700 × 10 ⁻⁸ ,
A ₈ = 1.3034 × 10 ^-9 , A ₁₀ = -1.1086 × 10 ^-11
(15th page)
k = 0,
A ₄ = -9.5990 × 10 ^-5 , A ₆ = -3.4358 × 10 ^-7 ,
A ₈ = −8.1549 × 10 ⁻¹⁰ , A ₁₀ = −2.1517 × 10 ⁻¹¹
(18th page)
k = 0,
A ₄ = 1.9209 × 10 ⁻⁶ , A ₆ = −1.3407 × 10 ⁻⁸ ,
A ₈ = -3.7331 × 10 ^-10 , A ₁₀ = 2.9350 × 10 ^-12
(19th page)
k = 0,
A ₄ = -1.6107 × 10 ^-5 , A ₆ = -3.2793 × 10 ^-8 ,
A ₈ = 2.5555 × 10 ⁻¹⁰ , A ₁₀ = −2.2617 × 10 ⁻¹³

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 21.851 11.818 2.500
D (14) 5.283 8.845 9.112
D (17) 6.326 2.765 2.497
D (19) 20.000 34.177 51.572

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₄₂₎ = 27.27
f3 (the focal length of the third lens group G ₄₃₎ = 52.44
f2 / f3 = 0.520

(Numerical value related to conditional expression (2))
Arufa3T (longitudinal magnification at the telephoto end of the third lens group G ₄₃₎ = 0.50

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₄₄₎ = - 27.85

(Numerical values related to conditional expression (4))
ra3 (curvature radius of the third object group G _{43 on} the most object side surface) =-21.904
rb3 (curvature of the most image plane side surface of the third lens group G ₄₃ radius) = - 12.782
ra3 / rb3 = 1.71

(Numerical values related to conditional expression (5))
fv (focal length of the vibration proof group VC ₄ ) = 203.00

  FIG. 11 is a longitudinal aberration diagram of the zoom lens according to Example 4; In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 12 is a lateral aberration diagram at the telephoto end of the zoom lens according to Example 4; In these figures, (a) indicates a base state not performing image stabilization at the telephoto end, (b) is 0.825mm moved in a direction substantially perpendicular to the vibration-proof group VC ₄ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The amount of image decentering when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image decentering amount when the image stabilizing group VC ₄ is translated by 0.825 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  12 (a) and 12 (b), the upper row shows the lateral aberration at the image point of 70% of the maximum image height, the middle row shows the lateral aberration at the axial image point, and the lower row shows -70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. It is also possible to take even greater than 0.3 ° of shake correction angle by applying the translation amount of vibration proof group VC ₄ in the wide-angle end and the intermediate focal position at the telephoto end.

FIG. 13 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the fifth example. The zoom lens includes a first lens group G ₅₁ having a negative refractive power, a second lens group G ₅₂ having a positive refractive power, and a third lens group having a positive refractive power in order from an object side (not shown). G ₅₃ and a fourth lens group G ₅₄ having negative refractive power are arranged. A cover glass CG is disposed between the fourth lens group G ₅₄ and the image plane IMG.

The first lens group G ₅₁ is constituted in order from the object side, a negative lens L _511, a negative lens L _512, a positive lens L _513, is the arrangement. Aspherical surfaces are formed on both surfaces of the negative lens L ₅₁₂ .

The second lens group G ₅₂ includes, in order from the object side, a positive lens L ₅₂₁ , an aperture stop STP that defines a predetermined aperture, a positive lens L ₅₂₂ , a negative lens L ₅₂₃ , a positive lens L _524, and a negative lens. L ₅₂₅ is arranged. Aspherical surfaces are formed on both surfaces of the positive lens _L521 . On the object side surface of the positive lens L ₅₂₄ , an aspheric surface is formed. Further, the positive lens L ₅₂₄ and the negative lens L ₅₂₅ are cemented.

The third lens group G ₅₃ includes a meniscus lens L ₅₃₁ having a positive refractive power with a concave surface facing the object side. Aspheric surfaces are formed on both surfaces of the meniscus lens L ₅₃₁ .

The fourth lens group G _54, constituted by a negative lens L _541.

In this zoom lens, during zooming from the wide-angle end to the telephoto end, the second lens group G ₅₂ , the third lens group G ₅₃ , and the fourth lens group G ₅₄ are moved along the optical axis from the image plane IMG side to the object side. Move to. At this time, the second lens group G ₅₂ and the fourth lens group G ₅₄ move along the locus of the same shape so that the movement amounts are equal. The first lens group G ₅₁ moves from the object side to the image plane IMG side along the optical axis from the wide-angle end to the vicinity of the intermediate focus position, and from the vicinity of the intermediate focus position to the telephoto end along the optical axis. Move from the surface IMG side to the object side. At the time of zooming from the wide angle end to the telephoto end, the distance between the first lens group G ₅₁ and the second lens group G ₅₂ becomes narrower.

In this zoom lens, the third lens group G ₅₃ is moved from the image plane IMG side to the object side along the optical axis, thereby performing focusing from the infinite focus state to the closest focus state. Further, the cemented lens and the positive lens L ₅₂₄ in the second lens group G ₅₂ composed of a negative lens L ₅₂₅ Metropolitan was play a function of the image stabilization unit VC _5, substantially perpendicular to the vibration-proof group VC ₅ with respect to the optical axis The camera shake is corrected by moving in the proper direction.

  Various numerical data relating to the zoom lens according to Example 5 will be described below.

F-number = 3.61 (wide-angle end) to 5.00 (intermediate focus position) to 5.77 (telephoto end)
Focal length of the entire zoom lens = 28.86 (fw: wide angle end) to 44.98 (intermediate focal position) to 67.91 (ft: telephoto end)
Half angle of view (ω) = 37.69 (wide-angle end) to 25.77 (intermediate focus position) to 17.47 (telephoto end)

(Lens data)
r ₁ = 35.723
d ₁ = 1.250 nd ₁ = 1.8348 νd ₁ = 47.72
r ₂ = 18.515
d ₂ = 12.544
r ₃ = -121.413 (aspherical surface)
d ₃ = 1.000 nd ₂ = 1.4971 νd ₂ = 81.56
r ₄ = 56.206 (aspherical surface)
d ₄ = 0.200
r ₅ = 38.696
d ₅ = 3.271 nd ₃ = 2.0010 νd ₃ = 29.13
r ₆ = 83.467
d ₆ = D (6) (variable)
r ₇ = 20.653 (aspherical surface)
d ₇ = 2.865 nd ₄ = 1.5891 νd ₄ = 61.25
r ₈ = 82.271 (aspherical surface)
d ₈ = 2.000
r ₉ = ∞ (aperture stop)
d ₉ = 2.000
r ₁₀ = 15.624
d ₁₀ = 1.911 nd ₅ = 1.4970 νd ₅ = 81.61
r ₁₁ = 25.974
d ₁₁ = 0.200
r ₁₂ = 19.479
d ₁₂ = 1.000 nd ₆ = 1.7618 νd ₆ = 26.61
r ₁₃ = 12.681
d ₁₃ = 3.229
r ₁₄ = 42.031 (aspherical surface)
d ₁₄ = 1.938 nd ₇ = 1.4971 νd ₇ = 81.56
r ₁₅ = -73.074
d ₁₅ = 1.500 nd ₈ = 1.8467 νd ₈ = 23.78
r ₁₆ = −110.939
d ₁₆ = D (16) (variable)
r ₁₇ = -19.737 (aspherical surface)
d ₁₇ = 5.000 nd ₉ = 1.4971 νd ₉ = 81.56
r ₁₈ = -13.668 (aspherical surface)
d ₁₈ = D (18) (variable)
r ₁₉ = -26.042
d ₁₉ = 0.700 nd ₁₀ = 1.4970 νd ₁₀ = 81.61
r ₂₀ = 3585.953
d ₂₀ = D (20) (variable)
r ₂₁ = ∞
d ₂₁ = 2.500 nd ₁₁ = 1.5168 νd ₁₁ = 64.2
r ₂₂ = ∞
d ₂₂ = 1.000
r ₂₃ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Third side)
k = 0,
A ₄ = -2.5073 × 10 ⁻⁶ , A ₆ = 6.5292 × 10 ⁻¹⁰ ,
A ₈ = 1.4106 × 10 ⁻¹⁰ , A ₁₀ = −3.8512 × 10 ⁻¹³
(Fourth surface)
k = 0,
A ₄ = -7.8452 × 10 ⁻⁶ , A ₆ = −4.3589 × 10 ⁻¹⁰ ,
A ₈ = 1.3316 × 10 ⁻¹⁰ , A ₁₀ = −5.1462 × 10 ⁻¹³
(Seventh side)
k = 0,
A ₄ = -5.7270 × 10 ^-6 , A ₆ = 1.0085 × 10 ^-8 ,
A ₈ = 1.6680 × 10 ^-11 , A ₁₀ = 5.8021 × 10 ^-13
(8th page)
k = 0,
A ₄ = 2.5217 × 10 ⁻⁷ , A ₆ = 9.3716 × 10 ⁻⁹ ,
A ₈ = 2.1683 × 10 ⁻¹⁰ , A ₁₀ = −7.2342 × 10 ⁻¹³
(14th page)
k = 0,
A ₄ = -2.7833 × 10 ^-6 , A ₆ = 4.1221 × 10 ^-8 ,
A ₈ = -8.1181 × 10 ^-10 , A ₁₀ = 5.0794 × 10 ^-12
(Seventeenth surface)
k = 0,
A ₄ = -1.0802 × 10 ^-4 , A ₆ = -9.7975 × 10 ^-7 ,
A ₈ = 6.2122 × 10 ⁻⁹ , A ₁₀ = −1.8343 × 10 ⁻¹⁰
(18th page)
k = 0,
A ₄ = -3.4443 × 10 ⁻⁵ , A ₆ = −4.5657 × 10 ⁻⁷ ,
A ₈ = 3.3027 × 10 ^-9 , A ₁₀ = -5.4020 × 10 ^-11

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 31.327 16.423 2.500
D (16) 6.168 12.032 12.052
D (18) 8.380 2.516 2.497
D (20) 20.017 34.268 51.050

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₅₂₎ = 34.04
f3 (the focal length of the third lens group G ₅₃₎ = 69.69
f2 / f3 = 0.487

(Numerical value related to conditional expression (2))
α3T (longitudinal magnification at the telephoto end of the third lens group G ₅₃ ) = 0.45

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₅₄₎ = - 51.87

(Numerical values related to conditional expression (4))
ra3 (radius of curvature of the third lens group G _{53 on} the most object side surface) =-19.737
rb3 (curvature of the most image plane side surface of the third lens group G ₅₃ radius) = - 13.668
ra3 / rb3 = 1.44

(Numerical values related to conditional expression (5))
fv (focal length of anti-vibration group VC ₅ ) = 68.48

  FIG. 14 is a longitudinal aberration diagram of the zoom lens according to Example 5. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 15 is a lateral aberration diagram at the telephoto end of the zoom lens according to Example 5; In these figures, (a) indicates a basic state not performing image stabilization at the telephoto end, (b) is 0.315mm moved in a direction substantially perpendicular to the vibration-proof group VC ₅ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The image decentering amount when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image decentering amount when the image stabilizing group VC ₅ is translated by 0.315 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  In FIGS. 15A and 15B, the upper stage shows lateral aberration at an image point of 70% of the maximum image height, the middle stage shows lateral aberration at an axial image point, and the lower stage shows −70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. It is also possible to take larger than the image stabilization angle by applying the translation amount to the wide angle end and the intermediate focal position state of the vibration-proof group VC ₅ 0.3 ° at the telephoto end.

FIG. 16 is a cross-sectional view along the optical axis showing the configuration of the zoom lens according to the sixth example. The zoom lens includes a first lens group G ₆₁ having a negative refractive power, a second lens group G ₆₂ having a positive refractive power, and a third lens group having a positive refractive power in order from an object side (not shown). G ₆₃ and a fourth lens group G ₆₄ having negative refractive power are arranged. Between the fourth lens group G ₆₄ and an image plane IMG, a cover glass CG is disposed.

The first lens group G ₆₁ is constituted in order from the object side, a negative lens L _611, a negative lens L _612, a positive lens L _613, is the arrangement.

The second lens group _G62 includes, in order from the object side, a positive lens _L621 , an aperture stop STP that defines a predetermined aperture, a positive lens _L622 , a negative lens _L623 , a positive lens _L624, and a positive lens. L ₆₂₅ is arranged. Aspherical surfaces are formed on both surfaces of each of the positive lens L ₆₂₁ and the positive lens L ₆₂₄ . Further, the positive lens L ₆₂₂ and the negative lens L ₆₂₃ are cemented.

The third lens group G ₆₃ includes a negative lens L ₆₃₁ and a positive lens L ₆₃₂ arranged in this order from the object side. An aspheric surface is formed on the object side surface of the negative lens L ₆₃₁ . The negative lens L ₆₃₁ and the positive lens L ₆₃₂ are cemented, and the third lens group G ₆₃ is configured as a meniscus lens having a concave surface facing the object side.

The fourth lens group _G64 includes a negative lens _L641 . Aspherical surfaces are formed on both surfaces of the negative lens L ₆₄₁ .

In this zoom lens, during zooming from the wide angle end to the telephoto end, the second lens group G ₆₂ , the third lens group G ₆₃ , and the fourth lens group G ₆₄ are moved along the optical axis from the image plane IMG side to the object side. Move to. At this time, the second lens group G ₆₂ and the fourth lens group G _64, which moves along a locus of the same shape as the amount of movement is equal. The first lens group G ₆₁ is, from the wide-angle end to the vicinity intermediate focal position is moved from the object side along the optical axis toward the image plane IMG side, from the intermediate focal position near to the telephoto end along the optical axis the image Move from the surface IMG side to the object side. At the time of zooming from the wide angle end to the telephoto end, the distance between the first lens group G ₆₁ and the second lens group G ₆₂ becomes narrower.

In this zoom lens, by moving from the image plane IMG to the side object side along the third lens group G ₆₃ to the optical axis to perform focusing from an infinity in-focus state to a closest distance in-focus state. Further, the positive lens L ₆₂₄ in the second lens group G ₆₂ has a function as the anti-vibration group VC ₆ ,
By moving to a direction substantially perpendicular to the optical axis of vibration-proof group VC _6, correcting the camera shake.

  Various numerical data relating to the zoom lens according to Example 6 will be described below.

F-number = 3.61 (wide-angle end) to 5.00 (intermediate focus position) to 5.77 (telephoto end)
Focal length of the entire zoom lens = 28.88 (fw: wide angle end) to 44.98 (intermediate focal position) to 67.90 (ft: telephoto end)
Half angle of view (ω) = 37.94 (wide angle end) to 25.88 (intermediate focus position) to 17.67 (telephoto end)

(Lens data)
r ₁ = 31.933
d ₁ = 1.250 nd ₁ = 1.8061 νd ₁ = 40.73
r ₂ = 17.743
d ₂ = 12.501
r ₃ = -75.628
d ₃ = 1.000 nd ₂ = 1.6385 νd ₂ = 55.45
r ₄ = 35.561
d ₄ = 0.200
r ₅ = 28.944
d ₅ = 4.067 nd ₃ = 1.8052 νd ₃ = 25.46
r ₆ = 140.712
d ₆ = D (6) (variable)
r ₇ = 27.001 (aspherical surface)
d ₇ = 3.139 nd ₄ = 1.5533 νd ₄ = 71.68
r ₈ = -378.813 (aspherical surface)
d ₈ = 2.000
r ₉ = ∞ (aperture stop)
d ₉ = 2.000
r ₁₀ = 33.44
d ₁₀ = 4.505 nd ₅ = 1.5688 νd ₅ = 56.04
r ₁₁ = -25.596
d ₁₁ = 1.000 nd ₆ = 1.7847 νd ₆ = 25.72
r ₁₂ = 50.53
d ₁₂ = 1.910
r ₁₃ = 46.774 (aspherical surface)
d ₁₃ = 1.640 nd ₇ = 1.4971 νd ₇ = 81.56
r ₁₄ = 747.77 (aspherical surface)
d ₁₄ = 2.459
r ₁₅ = -61.39
d ₁₅ = 1.473 nd ₈ = 1.9229 νd ₈ = 20.88
r ₁₆ = -30.962
d ₁₆ = D (16) (variable)
r ₁₇ = -20.951 (aspherical surface)
d ₁₇ = 2.189 nd ₉ = 1.5163 νd ₉ = 64.07
r ₁₈ = -315.441
d ₁₈ = 5.000 nd ₁₀ = 1.4970 νd ₁₀ = 81.61
r ₁₉ = -13.49
d ₁₉ = D (19) (variable)
r ₂₀ = -17.024 (aspherical surface)
d ₂₀ = 0.700 nd ₁₁ = 1.5182 νd ₁₁ = 56.96
r ₂₁ = -601.788 (aspherical surface)
d ₂₁ = D (21) (variable)
r ₂₂ = ∞
d ₂₂ = 2.500 nd ₁₂ = 1.5168 νd ₁₂ = 64.2
r ₂₃ = ∞
d ₂₃ = 1.000
r ₂₄ = ∞ (image plane)

Conical coefficient (k) and aspheric coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ )
(Seventh side)
k = 0,
A ₄ = -9.1559 × 10 ^-7 , A ₆ = 2.2426 × 10 ^-8 ,
A ₈ = -2.1982 × 10 ⁻¹⁰ , A ₁₀ = 3.9409 × 10 ⁻¹²
(8th page)
k = 0,
A ₄ = 2.4821 × 10 ⁻⁶ , A ₆ = 2.2100 × 10 ⁻⁸ ,
A ₈ = -1.0820 × 10 ^-10 , A ₁₀ = 3.5503 × 10 ^-12
(13th page)
k = 0,
A ₄ = 1.2694 × 10 ⁻⁵ , A ₆ = 9.5705 × 10 ⁻⁸ ,
A ₈ = 1.4678 × 10 ⁻⁹ , A ₁₀ = 1.9647 × 10 ⁻¹²
(14th page)
k = 0,
A ₄ = 1.7243 × 10 ⁻⁵ , A ₆ = 8.4286 × 10 ⁻⁸ ,
A ₈ = 1.8152 × 10 ⁻⁹ , A ₁₀ = 9.2244 × 10 ⁻¹³
(Seventeenth surface)
k = 0,
A ₄ = -8.1296 × 10 ^-5 , A ₆ = -3.1552 × 10 ^-7 ,
A ₈ = 7.2733 × 10 ⁻¹¹ , A ₁₀ = −2.6157 × 10 ⁻¹¹
(20th page)
k = 0,
A ₄ = 2.99587 × 10 ⁻⁶ , A ₆ = −2.0929 × 10 ⁻⁸ ,
A ₈ = 1.3106 × 10 ⁻¹⁰ , A ₁₀ = 3.7297 × 10 ⁻¹²
(21st surface)
k = 0,
A ₄ = -1.5751 × 10 ⁻⁵ , A ₆ = −3.00796 × 10 ⁻⁸ ,
A ₈ = 4.8079 × 10 ^-10 , A ₁₀ = -3.3631 × 10 ^-13

(Scaled data)
Wide-angle end Intermediate focus position Telephoto end
D (6) 22.377 9.920 2.500
D (16) 5.133 7.437 9.590
D (19) 6.955 4.652 2.498
D (21) 20.000 33.197 52.352

(Numerical values related to conditional expression (1))
f2 (the focal length of the second lens group G ₆₂₎ = 28.93
f3 (the focal length of the third lens group G ₆₃₎ = 60.11
f2 / f3 = 0.481

(Numerical value related to conditional expression (2))
α3T (longitudinal magnification at the telephoto end of the third lens group G ₆₃ ) = 0.53

(Numerical values related to conditional expression (3))
f4 (focal length of the fourth lens group G ₆₄₎ = - 33.68

(Numerical values related to conditional expression (4))
RA3 (curvature of the most object side surface of the third lens group G ₆₃ radius) = - 20.951
rb3 (curvature of the most image plane side surface of the third lens group G ₆₃ radius) = - 13.490
ra3 / rb3 = 1.55

(Numerical values related to conditional expression (5))
fv (focal length of anti-vibration group VC ₆ ) = 100.00

  FIG. 17 is a longitudinal aberration diagram of the zoom lens according to Example 6; In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long broken line is c The characteristic of the wavelength corresponding to the line (λ = 656.28 nm) is shown. In the astigmatism diagram, the vertical axis represents the half field angle (indicated by ω in the figure), the solid line represents the sagittal plane (indicated in the figure by S), and the broken line represents the meridional plane (indicated by M in the figure). Is shown. In the distortion diagram, the vertical axis represents a half angle of view (indicated by ω in the figure).

FIG. 18 is a lateral aberration diagram at a telephoto end of a zoom lens according to Example 6. In these figures, (a) indicates a basic state not performing image stabilization at the telephoto end, (b) is 0.422mm moved in a direction substantially perpendicular to the vibration-proof group VC ₆ with respect to the optical axis at the telephoto end The hand shake correction state is shown. The amount of image eccentricity when the shooting distance is ∞ and the zoom lens is tilted by 0.3 ° at the telephoto end is the image eccentricity when the image stabilizing group VC ₆ is translated by 0.422 mm in a direction substantially perpendicular to the optical axis. Equal to the amount.

  In FIGS. 18A and 18B, the upper stage shows lateral aberration at an image point of 70% of the maximum image height, the middle stage shows lateral aberration at an axial image point, and the lower stage shows -70% of the maximum image height. The lateral aberration at the image point is shown. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (λ = 587.56 nm), the short broken line is the g line (λ = 435.84 nm), and the long line The broken line indicates the wavelength characteristic corresponding to the c-line (λ = 656.28 nm).

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the camera shake correction state.

Also, when the camera shake correction angle of the zoom lens is the same, the amount of parallel movement necessary for camera shake correction decreases as the focal length of the entire zoom lens system decreases. Therefore, at any zoom position, it is possible to perform sufficient camera shake correction without deteriorating the imaging characteristics for camera shake correction angles up to 0.3 °. Further, by applying the parallel movement amount of the image stabilizing group VC ₆ at the telephoto end to the wide-angle end and the intermediate focus position state, the camera shake correction angle can be made larger than 0.3 °.

In the numerical data in each of the above embodiments, r ₁ , r ₂ ,... Are the curvature radii of the respective lenses and diaphragm surfaces, and d ₁ , d ₂ ,. thickness or their surface separations, nd _1, nd _2, the refractive index with respect to ... the d-line of each lens _{(λ = 587.56nm), νd 1} , νd 2, ···· are each lens d The Abbe number for the line (λ = 587.56 nm) is shown. The unit of length is all “mm”, and the unit of angle is “°”.

In addition, each of the above aspheric shapes has a depth of the aspheric surface Z, a curvature c (1 / r), a height from the optical axis h, a cone coefficient k, 4th order, 6th order, 8th order, 10th order. When the following aspheric coefficients are A ₄ , A ₆ , A ₈ , and A ₁₀ , respectively, and the light traveling direction is positive, the following aspheric coefficients are expressed by the following equations.

  As described above, the zoom lens of each embodiment described above satisfies the above-described conditional expressions, thereby reducing the total length of the optical system and suppressing the amount of movement of the focus group during focusing, and the angle of view during wobbling. A change in photographing magnification due to fluctuation can be suppressed. In addition, the focus group can be reduced in size and weight, and good focusing can be performed at high speed. Correction of various aberrations during focusing is also improved. Furthermore, by reducing the size and weight of the vibration-proof group, it is possible to maintain good optical performance even during camera shake correction. The diameter of the optical system can also be reduced. Furthermore, the ability to correct aberrations can be improved by arranging lenses or cemented lenses with appropriately formed aspheric surfaces.

<Application example>
Hereinafter, an example in which the zoom lens described in Embodiments 1 to 6 of the present invention is applied to an imaging apparatus will be described. FIG. 19 is a diagram illustrating an application example of an imaging apparatus including the zoom lens according to the present invention. FIG. 19 shows a state in which the lens barrel 110 containing the zoom lens 100 is attached to the imaging device 200.

  The zoom lens 100 is shown in Examples 1-6. The lens barrel 110 can be attached to and detached from the imaging apparatus 200 via the mount unit 111. As the mount portion 111, a screw type or bayonet type mount is used. In this example, a bayonet type mount is used.

  An image picked up by the zoom lens 100 is formed on an image pickup surface of an image pickup element 201 (CCD, CMOS, etc.) mounted on the image pickup apparatus 200, and an output signal from the image pickup element 201 relating to the image is a signal processing circuit (not shown). And the image is displayed on the display unit 202.

  By configuring as described above, it is possible to realize an imaging apparatus suitable for moving image shooting, which includes a small and high-performance zoom lens.

  FIG. 19 shows an example in which the zoom lens according to the present invention is used in a mirrorless single-lens camera. However, the zoom lens according to the present invention can be used not only for a single-lens mirrorless camera but also for other interchangeable lens cameras, digital still cameras, video cameras, and the like.

  As described above, the zoom lens according to the present invention is useful for a lens-exchanging small-sized imaging device such as a mirrorless single-lens camera, and is particularly suitable for an imaging device capable of moving image shooting.

_{G 11, G 21, G 31} , G 41, G 51, G 61 first lens group _{G 12, G 22, G 32} , G 42, G 52, G 62 second lens group G _13, G _23, G _{33 , G 43, G 53, G} 63 third lens group _{G 14, G 24, G 34} , G 44, G 54, G 64 fourth lens group _{L 111, L 112, L 123} , L 141, L 211, L ₂₁₂ , L ₂₂₃ , L ₂₄₁ , L ₃₁₁ , L ₃₁₂ , L ₃₂₃ , L ₃₄₁ , L ₄₁₁ , L ₄₁₂ , L ₄₂₃ , L ₄₃₁ , L ₄₄₁ , L ₅₁₁ , L ₅₁₂ , L ₅₂₃ , L ₅₂₅ , L ₅₄₁ , L ₆₁₁ , L ₆₁₂ , L ₆₂₃ , L ₆₃₁ , L ₆₄₁ negative lens L ₁₁₃ , L ₁₂₁ , L ₁₂₂ , L ₁₂₄ , L ₂₁₃ , L ₂₂₁ , L ₂₂₂ , L ₂₂₄ , L ₃₁₃ , L ₃₂₁ , L ₃₂₂ , L ₃₂₄ , L ₄₁₃ , L ₄₂₁ , L ₄₂₂ , L ₄₂₄ , L ₄₃₂ , L ₅₁₃ , L ₅₂₁ , L ₅₂₂ , L ₅₂₄ , L ₆₁₃ , L ₆₂₁ , L ₆₂₂ , L ₆₂₄ , L ₆₂₅ , L ₆₃₂ positive lens L _{131 , L 231, L 331, L} 531 meniscus lens VC _1, VC _{2 VC 3, VC 4, VC 5} , VC 6 vibration-proof group STP aperture stop CG cover glass IMG image plane 100 the zoom lens 110 the lens barrel 111 mounted portion 200 imaging apparatus 201 imaging device 202 display unit

Claims (5)

A first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a negative refractive power, which are arranged in order from the object side A fourth lens group,
During zooming from the wide-the Ri distance is narrowed between the first lens group and the third lens group, a distance between the third lens group and the third lens group is changed, wherein the in so that to change the spacing of the third lens group and said fourth lens group, the first lens group, the second lens group, the third lens group, and the fourth lens group along the optical axis moving Let
Focusing from the infinite focus state to the closest focus state is performed by moving the third lens group along the optical axis toward the object side,
The second lens group and the fourth lens group move along a locus of the same shape so that the amount of movement becomes equal upon zooming from the wide-angle end to the telephoto end,
A zoom lens that satisfies the following conditional expression:
(1) 0.330 ≦ f2 / f3 ≦ 0.650
(2) 0.45 ≦ α3T ≦ 0.58
Where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and α3T is the vertical magnification at the telephoto end of the third lens group. A first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a negative refractive power, which are arranged in order from the object side A fourth lens group,
Upon zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group is reduced, the distance between the second lens group and the third lens group is changed, and the third lens group is changed. Moving the first lens group, the second lens group, the third lens group, and the fourth lens group along the optical axis so that the distance between the lens group and the fourth lens group changes;
Focusing from the infinite focus state to the closest focus state is performed by moving the third lens group along the optical axis toward the object side,
A zoom lens that satisfies the following conditional expression:
(1) 0.330 ≦ f2 / f3 ≦ 0.650
(2) 0.45 ≦ α3T ≦ 0.58

Where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, α3T is the vertical magnification at the telephoto end of the third lens group, and f4 is the focal length of the fourth lens group. , Fw represents the focal length at the wide-angle end of the entire optical system, and ft represents the focal length at the telephoto end of the entire optical system. The third lens group is composed of a single lens element and has a meniscus shape with a concave toward the object side,
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(4) 1.10 ≦ ra3 / rb3 ≦ 5.00
Here, ra3 represents the radius of curvature of the most object side surface of the third lens group, and rb3 represents the radius of curvature of the most image side surface of the third lens group. The second lens group includes a vibration-proof group made up of a single lens element that moves in a direction substantially perpendicular to the optical axis and performs camera shake correction.
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.

Where fv is the focal length of the image stabilizing group, fw is the focal length at the wide angle end of the entire optical system, and ft is the focal length at the telephoto end of the entire optical system. An imaging apparatus comprising: the zoom lens according to claim 1; and an imaging element that converts an optical image formed by the zoom lens into an electrical signal.

Images