JP2015138178A - Zoom lens and image capturing device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens capable of rapidly performing camera shake correction while maintaining good optical performance during the camera shake correction.SOLUTION: A zoom lens comprises, in order from the object side to the image side, a positive first lens group, a negative second lens group, a positive third lens group, and a rear group comprising at least one lens group, and distance between each pair of adjacent lens groups changes while zooming such that distance between the first lens group and the second lens group widens and distance between the second lens group and the third lens group narrows. The second lens group comprises, in order from the object side to the image side, an anti-shake group and an image-side subgroup, where the anti-shake group moves in a direction having a component perpendicular to an optical axis when camera shake correction is activated. A focal length f2IS of the anti-shake group, a focal length f2p of the image-side subgroup, and focal length fT of the entire system at the telephoto end are each set appropriately.

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, for example, an image pickup apparatus using an image pickup device such as a video camera, an electronic still camera, a broadcast camera, a surveillance camera, or a camera using a silver salt film. It is suitable for the apparatus.

  The imaging optical system used in the imaging apparatus has a short overall lens length (distance from the first lens surface to the image plane), the entire system is small (compact), and a high zoom ratio with high optical performance over the entire zoom range. It is required to be a zoom lens. Furthermore, there is a demand for a zoom lens having a vibration-proof function that suppresses camera shake during shooting and image shake due to vibration of the shooting apparatus. A zoom lens in which a part of a lens system is shifted in a direction perpendicular to the optical axis is known as means for correcting image blur (means having an image stabilization function) (Patent Documents 1 to 3).

  In Patent Document 1, in order from the object side to the image side, a four-group zoom lens composed of first to fourth lens groups having positive, negative, positive, and positive refractive power, and positive, negative, positive, positive, and positive Discloses a five-unit zoom lens composed of a first lens unit to a fifth lens unit having a refractive power of 5 mm. Then, the image blur is corrected by moving the 21st group having a negative refractive power in a part of the second lens group in a direction orthogonal to the optical axis.

  Patent Document 2 discloses a five-unit zoom lens including first to fifth lens units having positive, negative, positive, positive, and negative refractive powers in order from the object side to the image side. Then, the image blur is corrected by decentering the second GrA having a negative refractive power in the second lens unit in the direction perpendicular to the optical axis.

  Patent Document 3 discloses a four-unit zoom lens including first to fourth lens units having positive, negative, positive (or negative), and positive refractive power in order from the object side to the image side. The second lens group is divided into three lens components, a lens component G2A, a lens component G2B, and a lens component G2C, and among these, the lens component G2B is moved perpendicularly to the optical axis to correct image blur. .

Japanese Patent Laid-Open No. 06-297868 JP-A-11-202201 JP 2002-296501 A

  In general, in a zoom lens having an image stabilization function, it is important to efficiently perform image blur correction and reduce aberration fluctuations during image blur correction. For this purpose, it is important to appropriately select the lens configuration of the zoom lens, the selection of the image stabilization system for image blur correction, the lens configuration of the image stabilization system, and the like. If the image stabilization system to be moved for image blur correction is not selected and the lens configuration of the image stabilization system is not appropriate, the image stabilization system will become large, making it difficult to correct image blur quickly, and to generate decentration aberrations during image stabilization. The amount increases, making it difficult to maintain high optical performance during vibration isolation.

  In addition, if the image stabilization sensitivity is low, the amount of eccentricity of the image stabilization system when a predetermined amount of image stabilization is performed increases, and the image stabilization system increases in size and the drive mechanism that drives the image stabilization system increases in size. It becomes difficult to reduce the size of the system.

  The anti-vibration sensitivity in this specification refers to the change in the angle of the principal ray on the incident side of a light beam that is formed at an image height of 0 mm (center of the screen) with respect to the amount of movement in the direction perpendicular to the optical axis of the anti-vibration system It is the ratio of (change in image position). As the image stabilization sensitivity value is larger, the angle of the light beam reaching the image plane can be changed by slightly moving the image stabilization system, so that a higher image stabilization capability is provided. The small size of the zoom lens means that the total length of the zoom lens (length in the direction parallel to the optical axis) is short or that the outer diameter of the lens when the zoom lens is combined with its drive mechanism is small. To do.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens capable of performing image blur correction at high speed and maintaining good optical performance during the image blur correction, and an image pickup apparatus having the zoom lens.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and one or more lens groups. In a zoom lens that includes a rear group having a distance between adjacent lens groups during zooming,
The distance between the first lens group and the second lens group is wider at the telephoto end than at the wide-angle end, and the distance between the second lens group and the third lens group is narrowed,
The second lens group includes, in order from the object side to the image side, an anti-vibration group having a negative refractive power and an image side partial group having a positive refractive power.
The image stabilization group moves so as to have a component in the direction perpendicular to the optical axis during image blur correction,
When the focal length of the image stabilizing group is f2IS, the focal length of the image side subgroup is f2p, and the focal length of the entire system at the telephoto end is fT,
0.050 <| f2IS | / fT <0.115
0.10 <f2p / fT <0.18
It satisfies the following conditional expression.

  According to the present invention, it is possible to obtain a zoom lens capable of performing image blur correction at high speed and maintaining good optical performance during image blur correction.

Lens cross-sectional view at the wide-angle end of the zoom lens of Example 1 (A), (b) Longitudinal aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 1 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 1 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 1 (object distance: infinity, when the image stabilizing group is moved 0.5 mm in the direction perpendicular to the optical axis) Lens sectional view at the wide-angle end of the zoom lens according to Embodiment 2 (A), (b) Longitudinal aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 2 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 2 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 2 (object distance: infinity, when the image stabilizing group is moved 0.5 mm in the direction perpendicular to the optical axis) Lens sectional view at the wide-angle end of the zoom lens according to Embodiment 3 (A), (b) Longitudinal aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 3 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 3 (object distance: infinity) (A), (b) Lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 3 (object distance: infinity, when the image stabilizing group is moved 0.5 mm in the direction perpendicular to the optical axis) Schematic diagram of main parts of an imaging apparatus of the present invention

  The best mode of the zoom lens of the present invention and the image pickup apparatus having the same will be described below. The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and one or more lens groups. The distance between adjacent lens groups changes during zooming. The distance between the first lens group and the second lens group is larger at the telephoto end than at the wide-angle end, and the distance between the second lens group and the third lens group is narrower at the telephoto end. Further, the distance between the third lens group and the lens group closest to the object side in the rear group is reduced.

  The second lens group includes a second IS lens system (anti-vibration group) having negative refractive power and a second p lens system (image-side partial group) having positive refractive power on the image side of the second IS lens system. During zooming, the distance between the second IS lens system and the second p lens system is constant. During image blur correction, the second IS lens system moves so as to have a component perpendicular to the optical axis.

  FIG. 1 is a lens cross-sectional view at the wide angle end according to Embodiment 1 of the present invention. FIGS. 2A and 2B are longitudinal aberration diagrams of the zoom lens of Example 1 at the wide-angle end and the telephoto end, respectively. FIGS. 3A and 3B are lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 1, respectively. FIGS. 4A and 4B are lateral aberration diagrams at the wide-angle end and the telephoto end, respectively, at the time of image shake correction of the zoom lens of Example 1. FIGS. Example 1 is a zoom lens having a zoom ratio of 2.85 and an aperture ratio of about 4.16 to 5.88.

  FIG. 5 is a lens cross-sectional view at the wide angle end according to Embodiment 2 of the present invention. FIGS. 6A and 6B are longitudinal aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end, respectively. FIGS. 7A and 7B are lateral aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end, respectively. FIGS. 8A and 8B are lateral aberration diagrams at the wide-angle end and the telephoto end, respectively, at the time of image shake correction of the zoom lens of Example 2. FIGS. The second embodiment is a zoom lens having a zoom ratio of 2.84 and an aperture ratio of about 4.16 to 5.88.

  FIG. 9 is a lens cross-sectional view at the wide angle end according to Embodiment 3 of the present invention. FIGS. 10A and 10B are longitudinal aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end, respectively. FIGS. 11A and 11B are lateral aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end, respectively. 12A and 12B are lateral aberration diagrams at the wide-angle end and the telephoto end, respectively, at the time of image shake correction of the zoom lens of Example 3. FIG. Embodiment 3 is a zoom lens having a zoom ratio of 2.85 and an aperture ratio of about 4.16 to 5.88. FIG. 13 is a schematic view of the main part of the imaging apparatus of the present invention.

  The zoom lens of the present invention is used for an imaging apparatus such as a digital camera, a video camera, a silver salt film camera, or the like. In the lens cross-sectional view, the left is the front (object side, enlargement side) and the right is the rear (image side, reduction side). In the lens cross-sectional view, i indicates the order of the lens groups from the object side to the image side, and Li is the i-th lens group. LR is a rear group having one or more lens groups. SP is an F number determining member (hereinafter also referred to as “aperture stop”) that functions as an aperture stop that determines (limits) an open F number (Fno) light beam.

  IP is an image plane, and when used as an imaging optical system for a video camera or a digital still camera, an imaging plane of an imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is placed. Further, when used as a photographing optical system for a silver salt film camera, a photosensitive surface corresponding to the film surface is provided. In the longitudinal aberration diagram, spherical aberration d represents d-line, g represents g-line, astigmatism ΔM represents meridional image surface, ΔS represents sagittal image surface, and lateral chromatic aberration g represents g-line. In the lateral aberration diagram, hgt is the image height. A broken line ΔS represents a sagittal image plane of the d line, and a solid line represents a meridional image plane of the d line.

  Fno is an F number, and ω is a half angle of view (degrees). The half angle of view ω is a value based on the ray tracing value. In the lens cross-sectional view, arrows indicate the movement trajectory of each lens unit during zooming from the wide-angle end to the telephoto end. The moving direction of the lens system during image blur correction is also shown.

  In each of the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zoom lens unit is positioned at both ends of the range in which the zoom lens unit can be moved on the optical axis due to the mechanism.

  The zoom lens according to each embodiment includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive refractive power. The rear group LR having the above lens groups is used. During zooming, the distance between adjacent lens groups changes as described above. In each embodiment, the first lens unit L1 has a positive refractive power, and has a total lens length (a value obtained by adding a back focus (air equivalent) value to the distance from the first lens surface to the final lens surface). It is easy to shorten.

  In the zoom lens of each embodiment, image blur correction (anti-vibration) is performed using a part of the lens system in the second lens unit L2 having negative refractive power as an anti-vibration lens system. The technical reason why this is the preferred configuration is as follows.

  As a first reason, it is desirable that the vibration-proof lens system is small in order to perform image blur correction at high speed and to reduce the size of a mechanism that holds and drives the vibration-proof lens system. In general, in a zoom lens having at least three lens groups of positive, negative, and positive refractive powers from the first lens group to the third lens group, an aperture stop is provided in the second lens group or the third lens group. Often has. In the lens group having a negative refractive power near the aperture stop, the axial luminous flux and the off-axial luminous flux are densely gathered, so that the effective lens diameter of the second lens group becomes small. Therefore, it is suitable for reducing the size of the optical system that image blur correction is performed with some lens systems in the second lens unit having a negative refractive power.

  As a second reason, in order to reduce a decrease in optical performance during image blur correction, it is preferable to perform image blur correction with some lens systems in the second lens group.

  As described in Patent Document 1 proposed by the present applicant, in order to correct the eccentric field curvature that occurs during image blur correction while increasing the image stabilization sensitivity of the image stabilization lens system. There are two refractive index arrangements, candidate 1 and candidate 2 listed in Table 1. The O group, the P group, and the Q group in Table 1 include a lens group that is disposed on the object side of the lens group that includes the image stabilization lens system, a lens group that includes the image stabilization lens system, and an image stabilization lens system, respectively. The lens group arrange | positioned at the image side of the lens group is represented.

According to Table 1, in a zoom lens having at least three lens groups, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, It is preferable to perform image blur correction in the second lens unit having a negative refractive power as in candidate 1 of 1. According to this, it becomes easy to satisfactorily correct aberration fluctuation during image blur correction. For these two reasons, in each embodiment, by performing image blur correction with the lens system in the second lens unit having a negative refractive power, the optical performance at the time of image blur correction is improved while reducing the size of the optical system. To maintain.

  In order to reduce the size of the drive mechanism of the vibration-proof lens system, it is necessary to increase the vibration-proof sensitivity. However, if the anti-vibration sensitivity of the entire second lens group is to be increased, the negative refractive power of the entire second lens group becomes too large. As a result, large spherical aberration occurs particularly on the wide angle side. If the spherical aberration at this time is corrected by the third and subsequent lens groups, coma will increase on the telephoto side. After all, it becomes difficult to maintain good optical performance over the entire zoom range.

  In order to maintain a good optical performance during image blur correction while reducing the size of the image stabilization mechanism, each embodiment is configured as follows. That is, in order from the object side to the image side, the second lens unit L2 includes a second IS lens system (anti-vibration group) L2IS having a negative refractive power and a second p lens system (image side partial group) L2p having a positive refractive power. Divide into at least two subgroups. Then, image blur correction is performed only in the second IS lens system L2IS. In addition, another partial lens system (partial group) is provided on the object side of the second IS lens system L2IS, between the second IS lens system L2IS and the second p lens system L2p, or on the image side of the second p lens system L2p. It doesn't matter.

  By dividing the second lens unit L2 into a plurality of partial lens systems, the refractive power (the absolute value of the negative refractive power) of the second IS lens system L2IS having a negative refractive power is increased to prevent image blur correction. The vibration sensitivity is increased to reduce the size of the drive mechanism. In addition, by using only a part of the second lens unit L2 as a vibration-proof lens system, the vibration-proof lens system is reduced in size and weight, and the drive mechanism is reduced in size.

  The second p lens system L2p preferably has a positive refractive power of a predetermined value and is disposed at a position closer to the image side than the second IS lens system L2IS. With such a refractive power arrangement, the negative refractive power of the second lens unit L2 as a whole can be appropriately maintained, and it becomes easy to satisfactorily correct coma particularly on the telephoto side. In addition, the effective lens diameter of the third lens unit L3 and subsequent lenses can be reduced to facilitate downsizing of the entire system.

  Specifically, the second lens unit L2 is preferably configured as follows in order from the object side to the image side. 2a lens system (object-side subgroup) L2a having a negative refractive power, and a second IS lens system (antivibration group) L2IS having a negative refractive power that moves so as to have a component perpendicular to the optical axis during image shake correction. The second p lens system (image side partial group) L2p having a positive refractive power is preferably used.

  In addition, the second lens unit L2 includes, in order from the object side to the image side, the second IS lens system L2IS having a negative refractive power that moves so as to have a component perpendicular to the optical axis when correcting image blur. It is preferable that the second p lens system L2p of force is configured. In addition, the second lens unit L2 includes, in order from the object side to the image side, a second-a lens system L2a having a positive refractive power, and a negative refractive power that moves so as to have a component in a direction perpendicular to the optical axis during image blur correction. The second IS lens system L2IS and the second p lens system L2p having a positive refractive power are preferably used.

In each embodiment, the focal length of the second IS lens system L2IS is f2IS, the focal length of the second p lens system L2p is f2p, and the focal length of the entire system at the telephoto end is fT. At this time,
0.050 <| f2IS | / fT <0.115 (1)
0.10 <f2p / fT <0.18 (2)
The following conditional expression is satisfied.

  Next, the technical meaning of each conditional expression described above will be described. Conditional expression (1) defines the ratio of the focal length of the second IS lens system L2IS to the focal length of the entire system at the telephoto end. Conditional expression (1) is mainly for maintaining good optical performance at the time of image blur correction and non-image blur correction while reducing the size of the entire system.

  If the upper limit of conditional expression (1) is exceeded, the negative refractive power of the second IS lens system L2IS becomes small (the absolute value of the negative refractive power becomes small), and a predetermined vibration proof sensitivity is obtained at the telephoto end. It becomes difficult, and it becomes necessary to increase the driving amount when performing image blur correction.

  As a result, the effective diameter of the second IS lens system L2IS is increased, and it is difficult to reduce the size of the entire system. If the lower limit of conditional expression (1) is not reached, the negative refractive power of the second IS lens system L2IS increases (the absolute value of the negative refractive power increases), and spherical aberration from the second IS lens system L2IS when image blur is not corrected. Large coma aberration occurs. Then, it becomes difficult to correct these various aberrations by the lens system after the second p lens system L2p. In addition, the coma aberration fluctuates at the telephoto end during image blur correction, and the optical performance during image blur correction also deteriorates.

  By satisfying the conditional expression (1), it is possible to obtain high optical performance in which various aberrations are favorably corrected both when image blur is corrected and when image blur is not corrected, while reducing the size of the entire system.

  Conditional expression (2) defines the ratio of the focal length of the second p lens system L2p to the focal length of the entire system at the telephoto end. Conditional expression (2) is mainly for obtaining high optical performance while reducing the size of the entire system.

  If the upper limit of conditional expression (2) is exceeded and the positive refractive power of the second p lens system L2p is reduced, it will be difficult to correct the spherical aberration generated by the second IS lens system L2IS. In particular, at the wide-angle end, the incident diameter of the axial light beam increases in the second IS lens system. For this reason, if the refractive power of the second p lens system L2p is small, the diameter of the light beam incident on the third lens group increases, making it difficult to correct spherical aberration, coma aberration, and the like in the lens system after the third lens group L3. Become.

  In addition, the effective lens diameter after the third lens unit L3 is increased, and it is difficult to reduce the size of the entire system. If the refractive power of the second p lens system L2p is increased below the lower limit of the conditional expression (2), the coma aberration will be overcorrected at the telephoto end. By satisfying conditional expression (2), high optical performance is obtained while downsizing the entire system.

  As described above, according to each embodiment, it is possible to obtain a zoom lens having high optical performance in which various aberrations are favorably corrected both when image blur is corrected and when image blur is not corrected, while the entire system is small. Can do. More preferably, the numerical ranges of conditional expressions (1) and (2) are set as follows.

0.07 <| f2IS | / fT <0.11 (1a)
0.120 <f2p / fT <0.175 (2a)
Next, more preferable conditions in each embodiment will be described.

  Let the focal length of the first lens unit L1 be f1. Let the focal length of the second lens unit L2 be f2. Let the focal length of the third lens unit L3 be f3. At this time, it is preferable to satisfy one or more of the following conditional expressions.

1.20 <| f2 | / f3 <2.80 (3)
0.30 <f1 / fT <0.80 (4)
Next, the technical meaning of each conditional expression described above will be described.

  Conditional expression (3) defines the ratio of the focal length of the second lens unit L2 to the focal length of the third lens unit L3. Conditional expression (3) is for obtaining high optical performance while reducing the size of the entire system. If the upper limit of conditional expression (3) is exceeded and the positive refractive power of the third lens unit L3 becomes too strong, spherical aberration will increase, especially on the wide angle side, and it will be difficult to correct this aberration. Further, if the positive refractive power of the third lens unit L3 becomes too weak below the lower limit of the conditional expression (3), coma increases and it becomes difficult to correct this aberration. Or, in order to correct the coma aberration, the number of lenses must be increased. As a result, the total lens length becomes longer.

  By satisfying conditional expression (3), high optical performance is obtained while downsizing the entire system. Conditional expression (4) defines the ratio of the focal length of the first lens unit L1 to the focal length of the entire system at the telephoto end. Conditional expression (4) is mainly for obtaining high optical performance while downsizing the entire system.

  If the upper limit of conditional expression (4) is exceeded, the positive refractive power of the first lens unit L1 becomes too weak and aberration correction becomes easy on the telephoto side, but the so-called telephoto type refractive power arrangement becomes weak, The total lens length becomes longer. In addition, it is necessary to increase the distance for moving the first lens unit L1 during zooming from the wide-angle end to the telephoto end, and the mechanism for holding the first lens unit L1 and the mechanism for driving it are increased in size. Miniaturization becomes difficult. Below the lower limit of conditional expression (4), the positive refractive power of the first lens unit L1 becomes too strong, and it becomes difficult to correct spherical aberration and coma correction on the telephoto side.

  By satisfying conditional expression (4), high optical performance is obtained while downsizing the entire system. More preferably, the numerical ranges of conditional expressions (3) and (4) are set as follows.

1.50 <| f2 | / f3 <2.50 (3a)
0.40 <f1 / fT <0.60 (4a)
Next, a preferable configuration in each lens group will be described.

  In general, when an image stabilizing lens system is decentered so as to have a component perpendicular to the optical axis during image blur correction, a large amount of axial chromatic aberration, which is one of decentering aberrations, occurs. In order to reduce this, it is necessary to correct the chromatic aberration by the vibration-proof lens system itself. For this purpose, one or more negative lenses and one or more positive lenses are required. In addition, since the second IS lens system L2IS for image blur correction has the negative refractive power defined by the conditional expression (1), one or more positive lenses and two or more negative lenses are included in the second IS lens system L2IS. It is preferable to have.

  By configuring the second IS lens system L2IS with at least two negative lenses and at least one positive lens, spherical aberration can be corrected well when chromatic aberration is corrected and image blur is not corrected, and It is possible to reduce the fluctuation of coma aberration at the time of shake correction. And it becomes easy to obtain a zoom lens having high optical performance.

  The same applies to the first lens group L1, the second p lens system L2p, and the third lens group L3. In order to correct chromatic aberration in the lens group or the lens system, one or more positive lenses and one or more lenses are used. It is preferable to have a negative lens. With such a configuration, variation in chromatic aberration during zooming can be reduced, and a zoom lens having high optical performance can be easily obtained. Next, features of the optical system of each embodiment will be described.

[Example 1]
The zoom lens of Example 1 in FIG. 1 will be described. The zoom lens of Example 1 includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a fourth lens unit having a negative refractive power. It consists of L4. The rear group LR includes a fourth lens group L4. The second lens unit L2 includes, in order from the object side to the image side, a negative power 2a lens system (object side partial group) L2a, a negative refractive power second IS lens system (anti-proof) for image blur correction. The second lens group (image side partial group) L2p has a positive refractive power. The aperture stop SP is disposed on the object side of the third lens unit, and moves together with the third lens unit L3 during zooming.

  The distance between adjacent lens units changes during zooming. Specifically, from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the third lens group L3. And the fourth lens unit L4 are narrowed.

  As the moving direction, during zooming from the wide-angle end to the telephoto end, the first lens unit L1, the third lens unit L3, and the fourth lens unit L4 move to the object side, and the second lens unit L2 is convex on the image side. Move along the trajectory. The distance between the second a lens system L2a and the second IS lens system L2IS and the distance between the second IS lens system L2IS and the second p lens system L2p are constant during zooming. During focusing from infinity to the closest distance, the fourth lens unit L4 moves from the object side to the image side.

  Each lens group and lens system are configured as follows in order from the object side to the image side. The first lens unit L1 includes a positive lens, and a cemented lens in which a positive lens and a negative lens are cemented, and thereby chromatic aberration in the first lens unit L1 is favorably corrected. The second a lens system L2a is composed of a meniscus negative lens having a concave surface directed toward the object side, and corrects the spherical aberration of the on-axis light beam generated after the second IS lens system.

  The second IS lens system L21S is composed of a cemented lens obtained by cementing a negative lens and a positive lens, and a negative lens. The anti-vibration sensitivity of the second IS lens system L2IS is 1.59 at the wide-angle end and 0.74 at the telephoto end, and sufficient anti-vibration performance is obtained with a small amount of decentering. The second p lens system L2p includes a positive lens and a cemented lens in which a positive lens and a negative lens are cemented. The second p lens system L2p is corrected while favorably correcting various aberrations generated in the second IS lens system L2IS. The chromatic aberration that occurs inside is also corrected well.

  The third lens unit L3 includes a positive lens, a cemented lens obtained by cementing a negative lens and a positive lens, and a positive lens. The third lens unit L3 corrects various aberrations such as spherical aberration and coma generated in the first lens unit L1 and the second lens unit L2, and also corrects chromatic aberration generated in the third lens unit L3. doing. The fourth lens unit L4 includes a positive lens and a negative lens, and satisfactorily suppress aberration fluctuations during focusing. Further, miniaturization of the focus mechanism is realized by keeping the effective diameter of the fourth lens unit L4 small.

[Example 2]
The zoom lens of Example 2 in FIG. 5 will be described. The zoom lens of Example 2 includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a fourth lens unit having a negative refractive power. L4 includes a fifth lens unit L5 having a positive refractive power. The rear group LR includes a fourth lens group L4 and a fifth lens group L5. The second lens unit L2 includes, in order from the object side to the image side, a second IS lens system (anti-vibration group) L2IS having a negative refractive power for image blur correction, and a second p lens system (image side having a positive refractive power). Subgroup) It is composed of L2p. The aperture stop SP is disposed on the image side of the second lens unit L2.

  The distance between adjacent lens units changes during zooming. Specifically, the distance between the first lens group L1 and the second lens group L2 and the distance between the fourth lens group L4 and the fifth lens group L5 are wider at the telephoto end than at the wide angle end. Further, the distance between the second lens group L2 and the third lens group L3 and the distance between the third lens group L3 and the fourth lens group L4 are narrowed. During zooming, the second lens unit L2 and the aperture stop SP do not move.

  As for the moving direction, during zooming from the wide-angle end to the telephoto end, the first lens unit L1, the third lens unit L3, and the fourth lens unit L4 move to the object side, and the fifth lens unit L5 has a convex shape on the object side. Move along a trajectory. The distance between the second IS lens system L2IS and the second p lens system L2p is constant during zooming. During focusing from infinity to the closest distance, the fourth lens unit L4 moves from the object side to the image side.

  Each lens group and lens system are configured as follows in order from the object side to the image side. The first lens unit L1 includes a positive lens and a cemented lens in which a positive lens and a negative lens are cemented, and thereby corrects chromatic aberration in the first lens unit L1 satisfactorily. The second IS lens system L2IS includes a cemented lens obtained by cementing a negative lens and a positive lens, and a negative lens.

  The anti-vibration sensitivity of the second IS lens system L2IS is 1.79 at the wide-angle end and 0.75 at the telephoto end, and sufficient anti-vibration performance is obtained with a small amount of eccentricity. The second p lens system L2p is composed of a positive lens and a cemented lens in which a positive lens and a negative lens are cemented, and corrects various aberrations generated in the second IS lens system L2IS, while maintaining good correction in the second p lens system L2p. The chromatic aberration caused by the above is corrected well.

  The third lens unit L3 includes a positive lens, a cemented lens obtained by cementing a negative lens and a positive lens, and a positive lens. The third lens unit L3 corrects various aberrations such as spherical aberration and coma generated in the first lens unit L1 and the second lens unit L2, and also corrects chromatic aberration generated in the third lens unit L3. doing.

  The fourth lens unit L4 includes a positive lens and a negative lens, and satisfactorily suppress aberration fluctuations during focusing. Further, miniaturization of the focus mechanism is realized by keeping the effective diameter of the fourth lens unit L4 small.

  The fifth lens unit L5 is composed of a positive lens. By adopting a meniscus shape with the convex surface facing the object side, various aberrations such as distortion are corrected satisfactorily.

[Example 3]
A zoom lens according to Example 3 in FIG. 9 will be described. The zoom lens of Example 3 includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a fourth lens unit having a negative refractive power. It consists of L4. The rear group LR includes a fourth lens group L4. The second lens unit L2 includes, in order from the object side to the image side, a 2a lens system (object side partial group) L2a having a positive refractive power, and a second IS lens system having a negative refractive power for image blur correction (anti-proof). (Vibrating group) L2IS, and a second p lens system (image side partial group) L2p having a positive refractive power. The aperture stop SP is disposed on the object side of the third lens unit L3, and moves together with the third lens unit L3 during zooming.

  During zooming, the interval between adjacent lens groups changes. Specifically, the distance between the first lens unit L1 and the second lens unit L2 is widened at the telephoto end compared to the wide-angle end, and the interval between the second lens unit L2 and the third lens unit L3 is narrowed. The distance between the lens unit L3 and the fourth lens unit L4 is reduced. The moving direction of each lens group is the same as in the first embodiment. The distance between the second a lens system L2a and the second IS lens system L2IS and the distance between the second IS lens system L2IS and the second p lens system L2p are constant during zooming. During focusing from infinity to a close distance, the fourth lens unit L4 moves from the object side to the image side.

  Each lens group and lens system are configured as follows in order from the object side to the image side. The first lens unit L1 includes a positive lens and a cemented lens in which a positive lens and a negative lens are cemented, and thereby corrects chromatic aberration in the first lens unit L1 satisfactorily. The 2a lens system L2a is composed of a positive lens. The second a lens system L2a has a positive refractive power, and provides a sufficient negative refractive power to the second IS lens system L2IS while maintaining the negative refractive power of the second lens unit L2 as a whole. The anti-vibration sensitivity of the second IS lens system L2IS is increased.

  The second IS lens system L2IS includes a cemented lens obtained by cementing a negative lens and a positive lens, and a negative lens. The anti-vibration sensitivity of the second IS lens system L2IS is 1.70 at the wide-angle end and 0.78 at the telephoto end, and sufficient anti-vibration performance is obtained with a small amount of eccentricity. The second p lens system L2p is composed of a positive lens and a cemented lens obtained by cementing a positive lens and a negative lens, and is generated in the second p lens system L2p while favorably correcting various aberrations generated in the second IS lens system L2IS. The chromatic aberration is also corrected well.

  The third lens unit L3 includes a positive lens, a negative lens, and a cemented lens obtained by cementing a positive lens. The third lens unit L3 corrects various aberrations such as spherical aberration and coma generated in the first lens unit L1 and the second lens unit L2, and also corrects chromatic aberration generated in the third lens unit L3. doing.

  The fourth lens unit L4 includes a negative lens, a positive lens, and a negative lens, and corrects spherical aberration well at the telephoto end. In addition, aberration variations during focusing are corrected satisfactorily. Further, miniaturization of the focus mechanism is realized by keeping the effective diameter of the fourth lens unit L4 small.

  As described above, the zoom lens according to the present embodiment has high optical performance in which various aberrations are favorably corrected both when image blur is corrected and when image blur is not corrected, while the entire system is small.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  FIG. 13 is a schematic diagram of a main part of a single-lens reflex camera (imaging device) having the zoom lens of the present invention. In FIG. 13, reference numeral 10 denotes a photographing optical system having any one zoom lens of Embodiments 1 to 3.

  The zoom lens 1 is held by a lens barrel 2 that is a holding member. Reference numeral 20 denotes a camera body. The camera body 20 includes a quick return mirror 3, a focusing screen 4, a penta roof prism 5, an eyepiece lens 6, and the like. The quick return mirror 3 reflects the light beam from the photographing optical system 10 upward. The focusing screen 4 is disposed at the image forming position of the photographing optical system 10. The penta roof prism 5 converts the reverse image formed on the focusing screen 4 into an erect image. An observer observes the erect image through the eyepiece 6.

  Reference numeral 7 denotes a photosensitive surface, on which a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives an image or a silver salt film is disposed. At the time of photographing, the quick return mirror 3 is retracted from the optical path, and is formed on the photosensitive surface 7 by the photographing optical system 10 on the image side.

  Thus, by applying the zoom lens of the present invention to an imaging apparatus such as a single-lens reflex camera, an imaging apparatus having high optical performance is realized. The zoom lens of the present invention can be applied to optical devices such as telescopes, binoculars, copying machines, projectors, etc. in addition to digital cameras, video cameras, silver salt film cameras, and the like. It can also be applied to a mirrorless single-lens reflex camera without a quick return mirror.

  Hereinafter, specific numerical data of numerical examples 1 to 3 corresponding to the first to third examples will be described. The surface number i is counted in order from the object side. ri is the radius of curvature (mm), and di is the i-th and i + 1-th surface separation (mm). ndi and νdi represent the refractive index and Abbe number of the medium between the i-th surface and the (i + 1) -th surface with respect to the d-line, respectively. In addition, Table 2 shows numerical values related to each numerical example and each conditional expression described above. Further, Table 3 shows numerical values corresponding to the above-described conditional expressions.

[Numerical Example 1]
Surface data surface number rd nd νd
1 93.407 5.00 1.48749 70.2
2 -1921.800 0.15
3 100.108 1.70 1.65412 39.7
4 46.230 7.00 1.49700 81.5
5 350.000 (variable)
6 -186.138 1.20 1.48749 70.2
7 -552.459 2.16
8 -213.071 1.10 1.71300 53.9
9 22.327 2.51 1.80809 22.8
10 47.555 2.33
11 -54.176 1.10 1.80 400 46.6
12 431.432 4.24
13 -234.686 2.25 1.77250 49.6
14 -53.235 0.20
15 65.554 4.99 1.58913 61.1
16 -29.234 1.12 1.90366 31.3
17 -79.438 (variable)
18 (Aperture) ∞ 10.96
19 1019.000 2.44 1.56732 42.8
20 -83.595 1.00
21 -218.096 1.00 1.80610 33.3
22 34.118 4.80 1.69680 55.5
23 -83.957 0.50
24 78.894 2.51 1.65844 50.9
25 -306.993 (variable)
26 1364.702 1.84 1.76182 26.5
27 -46.842 1.16
28 -43.388 0.80 1.74 100 52.6
29 33.478 (variable)
Image plane ∞

Variable interval
Wide angle Medium telephoto
d 5 8.87 51.24 68.92
d17 18.93 7.36 6.82
d25 27.91 13.25 2.50
d29 43.23 65.41 84.71

Various data
Wide angle Medium telephoto focal length 102.00 195.50 291.20
F number 4.16 5.14 5.88
Half angle of view (degrees) 7.63 4.00 2.69

[Numerical Example 2]
Surface data surface number rd nd νd
1 95.968 4.78 1.48749 70.2
2 -9164.561 0.15
3 94.823 1.70 1.65412 39.7
4 46.417 7.00 1.49700 81.5
5 350.000 (variable)
6 -270.226 1.20 1.71300 53.9
7 19.642 2.62 1.80809 22.8
8 39.887 2.56
9 -53.850 1.10 1.80400 46.6
10 164.877 4.24
11 320.993 2.42 1.80 400 46.6
12 -65.064 0.20
13 62.637 4.96 1.58913 61.1
14 -29.225 1.12 1.90366 31.3
15 -107.212 1.66
16 (Aperture) ∞ (Variable)
17 985.623 2.64 1.59551 39.2
18 -67.490 1.00
19 -254.020 1.00 1.80610 33.3
20 27.344 5.44 1.72916 54.7
21 -98.166 0.20
22 53.260 2.55 1.65844 50.9
23 691.206 (variable)
24 -183.386 1.49 1.76182 26.5
25 -49.083 1.02
26 -57.706 0.70 1.69680 55.5
27 24.331 (variable)
28 32.477 1.87 1.63980 34.5
29 46.207 (variable)
Image plane ∞

Variable interval
Wide angle Medium telephoto
d 5 13.32 55.57 77.32
d16 23.42 13.88 12.39
d23 23.42 11.85 2.00
d27 10.66 17.52 29.85
d29 38.55 52.81 51.82

Various data
Wide angle Medium telephoto focal length 102.63 195.50 291.20
F number 4.16 5.18 5.88
Half angle of view (degrees) 7.58 4.00 2.69

[Numerical Example 3]
Surface data surface number rd nd νd
1 91.662 5.00 1.48749 70.2
2 -8138.598 0.15
3 101.654 1.70 1.65412 39.7
4 46.326 7.00 1.49700 81.5
5 350.000 (variable)
6 69.601 1.20 1.48749 70.2
7 87.819 2.43
8 -447.069 1.10 1.71300 53.9
9 20.176 2.55 1.80809 22.8
10 40.928 2.61
11 -48.622 1.10 1.80 400 46.6
12 285.620 4.24
13 -117.151 2.16 1.77250 49.6
14 -44.197 0.20
15 58.299 4.83 1.58913 61.1
16 -29.966 1.12 1.90366 31.3
17 -98.644 (variable)
18 (Aperture) ∞ 12.54
19 -458.263 2.49 1.56732 42.8
20 -64.010 1.00
21 75.818 1.00 1.80610 33.3
22 22.655 5.44 1.72916 54.7
23 -173.059 (variable)
24 42.931 1.10 1.88300 40.8
25 27.473 1.80
26 -92.241 2.00 1.76182 26.5
27 -26.942 1.18
28 -25.071 0.90 1.74 100 52.6
29 -2486.987 (variable)
Image plane ∞

Variable interval
Wide angle Medium telephoto
d 5 8.47 52.84 70.96
d17 19.17 8.48 8.73
d23 29.94 13.62 1.50
d29 38.58 59.69 78.98

Various data
Wide angle Medium telephoto focal length 102.00 195.50 291.20
F number 4.16 5.07 5.88
Half angle of view (degrees) 7.63 4.00 2.69

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group L5 5th lens group LR Rear group L2a 2a lens system L2IS 2IS lens system L2p 2p lens system

Claims (14)

In order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a rear group having one or more lens groups. In zoom lenses in which the distance between adjacent lens groups changes during zooming,
The distance between the first lens group and the second lens group is wider at the telephoto end than at the wide-angle end, and the distance between the second lens group and the third lens group is narrowed,
The second lens group includes, in order from the object side to the image side, an anti-vibration group having a negative refractive power and an image side partial group having a positive refractive power.
The image stabilization group moves so as to have a component in the direction perpendicular to the optical axis during image blur correction,
When the focal length of the image stabilizing group is f2IS, the focal length of the image side subgroup is f2p, and the focal length of the entire system at the telephoto end is fT,
0.050 <| f2IS | / fT <0.115
0.10 <f2p / fT <0.18
A zoom lens satisfying the following conditional expression: When the focal length of the second lens group is f2, and the focal length of the third lens group is f3,
1.20 <| f2 | / f3 <2.80
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first lens group is f1,
0.30 <f1 / fT <0.80
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The zoom lens according to any one of claims 1 to 3, wherein the image stabilization group includes one or more positive lenses and two negative lenses.   4. The zoom lens according to claim 1, wherein the image-side partial group includes one or more positive lenses and one negative lens. 5.   The zoom lens according to claim 1, wherein the first lens group includes a positive lens and a negative lens.   The zoom lens according to claim 1, wherein the third lens group includes a positive lens and a negative lens.   The zoom lens according to any one of claims 1 to 7, wherein the rear group includes a fourth lens group having a negative refractive power, and the fourth lens group moves during focusing.   The rear group includes a fourth lens group having a negative refractive power, and the first lens group, the third lens group, and the fourth lens group move toward the object side during zooming from the wide-angle end to the telephoto end. The zoom lens according to any one of claims 1 to 7, wherein the second lens group moves along a convex locus toward the image side, and the fourth lens group moves during focusing.   The rear group includes, in order from the object side to the image side, a fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, and the second lens group does not move during zooming, and has a wide-angle end. During zooming from the telephoto end to the telephoto end, the first lens group, the third lens group, and the fourth lens group move toward the object side, and the fifth lens group moves along a convex locus toward the object side, and during focusing The zoom lens according to claim 1, wherein the fourth lens group moves.   The said 2nd lens group is comprised from the object side partial group of the negative refractive power in order from the object side to the image side, the said image stabilization group, and the said image side partial group. Zoom lens.   The zoom lens according to claim 10, wherein the second lens group includes the image stabilizing group and the image side partial group in order from the object side to the image side.   10. The zoom according to claim 9, wherein the second lens group includes, in order from the object side to the image side, an object side partial group having a positive refractive power, the image stabilization group, and the image side partial group. lens.   An imaging apparatus comprising: the zoom lens according to claim 1; and a photoelectric conversion element that receives an image formed by the zoom lens.