JP5699950B2 - Zoom lens, imaging optical device and digital device - Google Patents

Description

  The present invention relates to a zoom lens, an imaging optical device, and a digital device. For example, a large aperture suitable for an interchangeable lens digital camera that captures an image of a subject with an image sensor (for example, a solid-state image sensor such as a charge coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor). And compact wide-angle zoom lens, an imaging optical device that outputs an image of a subject captured by the zoom lens and the imaging device as an electrical signal, and a digital device with an image input function such as a digital camera equipped with the imaging optical device And is about.

  In recent years, digital cameras are commonly used in interchangeable lens cameras, and not only still image shooting by autofocus but also moving image shooting and the like are possible. Since sound is recorded at the same time when shooting a movie, it is necessary to minimize the operating sound from the camera and lens. The problem of operating noise on the lens side is the operating sound of actuators used for focus and camera shake correction. Therefore, it is necessary to reduce the noise, but in order to reduce the operating noise of the actuator, the lens group that moves with the focus (that is, the focus group) is required to be lighter in the design of the photographing lens.

  As a large-aperture wide-angle zoom lens for an interchangeable lens, a lens type having a negative / positive / negative-positive power arrangement is generally known (for example, see Patent Documents 1 and 2). As such a zoom type focusing method, focusing is generally performed by moving the entire negative first group. However, in the zoom lens described in Patent Document 1, the second group is divided into two and moved. Focusing is performed, and the zoom lens described in Patent Document 2 employs a method of performing focusing by dividing the first group into two parts and moving them. Further, Patent Document 3 proposes a standard zoom lens composed of six negative, positive, positive, positive, and positive groups that performs focusing by moving the fifth group.

JP 2000-221399 A JP 2002-31330 A JP 2004-198529 A

  In the zoom lenses described in Patent Documents 1 and 2, the weight of the focus group is not sufficiently reduced. In the zoom lens described in Patent Document 3, it is difficult to reduce the weight because the focus group is composed of a cemented lens, and it does not cover a wide angle region.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a compact and high-performance zoom lens having a wide-angle and large-diameter and a light focus group, and an imaging optical apparatus including the same. And providing digital equipment.

In order to achieve the above object, a zoom lens according to a first invention comprises, in order from the object side, a first group having negative power, a second group having positive power, a third group having negative power, and a positive group. A zoom lens system comprising a fourth group having power, a fifth group having negative power, and a sixth group having positive power, wherein zooming is performed by changing the interval between the groups. Focusing on a short distance object is performed by moving the group to the image side, and the fifth group is composed of a single lens that satisfies the following conditional expression (1).
0.2 <(CR1-CR2) / (CR1 + CR2) <0.4 (1)
However,
CR1: radius of curvature of the object side surface,
CR2: radius of curvature of image side surface,
It is.

A zoom lens according to a second aspect of the invention is characterized in that, in the first aspect of the invention, the following conditional expression (2) is satisfied.
2.5 <f5 / f1 <6 (2)
However,
f5: focal length of the fifth group,
f1: focal length of the first group,
It is.

A zoom lens according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the following conditional expression (4) is satisfied.
-2.5 <f2_4w / f1 <-1.6 (4)
However,
f2 — 4w: the combined focal length from the second group to the fourth group at the wide end,
f1: focal length of the first group,
It is.

  A zoom lens according to a fourth invention is characterized in that, in any one of the first to third inventions, the second group and the fourth group move while maintaining a constant interval during zooming. And

  A zoom lens according to a fifth aspect of the present invention is the zoom lens according to any one of the first to fourth aspects, further comprising a stop on the image side of the second group, and the stop moves together with the second group during zooming. It is characterized by.

  A zoom lens according to a sixth aspect of the present invention is the interchangeable lens for a digital camera according to any one of the first to fifth aspects.

  An imaging optical device according to a seventh aspect includes the zoom lens according to any one of the first to sixth aspects, and an imaging element that converts an optical image formed on the light receiving surface into an electrical signal. And the zoom lens is provided so that an optical image of a subject is formed on a light receiving surface of the image sensor.

  A digital apparatus according to an eighth aspect is characterized in that at least one of a still image photographing and a moving image photographing function of a subject is added by including the imaging optical device according to the seventh aspect.

  According to the present invention, since the conditions necessary for making a single lens for reducing the weight of the focus group are appropriately set, it is possible to reduce the weight of the focus group, for example, for focus and camera shake correction. Therefore, it is possible to achieve noise reduction by reducing the operating noise of the actuator used for the purpose. Therefore, it is possible to realize a compact and high-performance zoom lens and an imaging optical device regardless of the wide-angle and large-diameter and the light focus group. By using the zoom lens or the imaging optical device that is compact with a wide angle and a large aperture for a digital device (for example, a digital camera), a high-performance image input function can be added to the digital device in a compact manner. .

The optical block diagram of 1st Embodiment (Example 1). FIG. 4 is a longitudinal aberration diagram for the infinite object of Example 1. FIG. 6 is a lateral aberration diagram at a wide end with respect to an infinitely distant subject according to the first exemplary embodiment. FIG. 6 is a lateral aberration diagram in the intermediate focal length state with respect to an infinitely far subject according to the first embodiment. FIG. 6 is a lateral aberration diagram at the tele end with respect to an infinitely far subject according to the first embodiment. FIG. 4 is a longitudinal aberration diagram for the closest subject of Example 1. FIG. 6 is a lateral aberration diagram at the wide end with respect to the closest subject in Example 1. FIG. 6 is a lateral aberration diagram in the intermediate focal length state with respect to the closest subject according to the first embodiment. FIG. 6 is a lateral aberration diagram at the tele end with respect to the closest subject according to the first embodiment. The optical block diagram of 2nd Embodiment (Example 2). FIG. 6 is a longitudinal aberration diagram for an infinite object according to the second embodiment. FIG. 12 is a lateral aberration diagram at a wide end with respect to an infinitely far subject according to the second embodiment. FIG. 6 is a lateral aberration diagram in the intermediate focal length state with respect to an infinitely far subject according to the second embodiment. FIG. 12 is a lateral aberration diagram at the tele end with respect to an infinitely far subject according to the second embodiment. FIG. 6 is a longitudinal aberration diagram for the closest subject of Example 2. FIG. 12 is a lateral aberration diagram at the wide end with respect to the closest subject in Example 2. FIG. 12 is a lateral aberration diagram in the intermediate focal length state with respect to the closest subject according to the second embodiment. FIG. 6 is a lateral aberration diagram at the tele end with respect to the closest subject according to the second embodiment. The optical block diagram of 3rd Embodiment (Example 3). FIG. 6 is a longitudinal aberration diagram for an infinite object according to the third embodiment. FIG. 12 is a lateral aberration diagram at a wide end with respect to an infinite object in Example 3. FIG. 12 is a lateral aberration diagram in the intermediate focal length state with respect to an infinitely far subject according to the third embodiment. FIG. 12 is a lateral aberration diagram at the tele end with respect to an infinitely far subject according to the third embodiment. FIG. 6 is a longitudinal aberration diagram for the closest subject of Example 3. FIG. 11 is a lateral aberration diagram at the wide end with respect to the closest subject in Example 3. FIG. 12 is a lateral aberration diagram in the intermediate focal length state with respect to the closest subject according to the third embodiment. FIG. 12 is a lateral aberration diagram at the tele end with respect to the closest subject according to the third embodiment. The optical block diagram of 4th Embodiment (Example 4). FIG. 6 is a longitudinal aberration diagram for an infinitely distant subject according to the fourth exemplary embodiment. FIG. 12 is a lateral aberration diagram at a wide end with respect to an infinitely far subject according to the fourth embodiment. FIG. 10 is a lateral aberration diagram in the intermediate focal length state with respect to an infinitely far subject according to the fourth embodiment. FIG. 6 is a lateral aberration diagram at the tele end with respect to an infinitely far subject according to the fourth embodiment. FIG. 6 is a longitudinal aberration diagram for the closest subject of Example 4. FIG. 11 is a lateral aberration diagram at the wide end with respect to the closest subject in Example 4. FIG. 10 is a lateral aberration diagram in the intermediate focal length state with respect to the closest subject according to the fourth embodiment. FIG. 12 is a lateral aberration diagram at the tele end with respect to the closest subject according to the fourth embodiment. The optical block diagram of 5th Embodiment (Example 5). FIG. 12 is a longitudinal aberration diagram for an infinitely distant subject according to Example 5. FIG. 10 is a lateral aberration diagram at a wide end with respect to an infinite object in Example 5. FIG. 10 is a lateral aberration diagram in the intermediate focal length state with respect to an infinitely far subject according to the fifth embodiment. FIG. 9 is a lateral aberration diagram at the tele end with respect to an infinitely far subject according to the fifth embodiment. FIG. 10 is a longitudinal aberration diagram for the closest subject of Example 5. FIG. 12 is a lateral aberration diagram at the wide end with respect to the closest subject in Example 5. FIG. 10 is a lateral aberration diagram in the intermediate focal length state with respect to the closest subject according to the fifth embodiment. FIG. 10 is a lateral aberration diagram at the tele end with respect to the closest subject according to the fifth embodiment. FIG. 3 is a schematic diagram illustrating a schematic configuration example of a digital device equipped with an imaging optical device.

Hereinafter, a zoom lens, an imaging optical device, and a digital apparatus according to the present invention will be described. The zoom lens according to the present invention includes, in order from the object side, a first group having negative power, a second group having positive power, a third group having negative power, a fourth group having positive power, A zoom lens comprising a fifth group having power and a sixth group having positive power, and performing zooming by changing the distance between the groups, and moving the fifth group to the image side Focusing on a short distance object is performed, and the fifth group is composed of a single lens that satisfies the following conditional expression (1) (power: an amount defined by the reciprocal of the focal length).
0.2 <(CR1-CR2) / (CR1 + CR2) <0.4 (1)
However,
CR1: radius of curvature of the object side surface,
CR2: radius of curvature of image side surface,
It is.

  In order to reduce the weight of the focus group, in the zoom lens according to the present invention, the fifth group is configured by a negative single lens, and focusing is performed by moving the fifth group to the image side. In general, when focusing is performed by moving a lens group in a zoom lens system, the magnification relationship with the lens groups before and after the focus group changes, so that aberration fluctuations are likely to occur, and correction thereof is a problem. Become. Therefore, it is necessary to reduce the error sensitivity of spherical aberration, coma aberration, and astigmatism at the air space before and after the focus group.

  In the zoom lens according to the present invention, by forming the focus group with a single lens that satisfies the conditional expression (1), the aberration variation at the time of focusing is reduced, and good optical performance is achieved. Conditional expression (1) defines a preferable condition range for achieving the above-mentioned good optical performance with respect to the shape of the negative single lens constituting the fifth group which is the focus group. If the upper limit of conditional expression (1) is exceeded, the radius of curvature of the image side surface becomes too small and negative distortion increases, making it difficult to correct. If the lower limit of conditional expression (1) is exceeded, the astigmatism occurring in the fifth group will become large and it will be difficult to correct it.

  According to the above characteristic configuration, since the conditions necessary for making a single lens to reduce the weight of the focus group are appropriately set, the focus group can be reduced in weight, for example, focus and camera shake correction. It is possible to achieve noise reduction by reducing the operating noise of the actuator used for the purpose. Therefore, it is possible to realize a compact and high-performance zoom lens and an imaging optical device regardless of the wide-angle and large-diameter and the light focus group. If the zoom lens or imaging optical device is used in a digital device such as a digital camera, a high-performance image input function can be added to the digital device in a lightweight and compact manner. It can contribute to higher performance and higher functionality. In addition, since the zoom lens according to the present invention is suitable as an interchangeable lens for a lens interchangeable digital camera, it is possible to realize a lightweight and compact interchangeable lens that is convenient to carry. The conditions for achieving such effects in a well-balanced manner and achieving higher optical performance, downsizing, etc. will be described below.

It is more desirable to satisfy the following conditional expression (1a).
0.25 <(CR1-CR2) / (CR1 + CR2) <0.35 (1a)
The conditional expression (1a) defines a more preferable condition range based on the above viewpoints, etc., among the condition ranges defined by the conditional expression (1). Therefore, the above effect can be further enhanced preferably by satisfying conditional expression (1a).

It is desirable to satisfy the following conditional expression (2).
2.5 <f5 / f1 <6 (2)
However,
f5: focal length of the fifth group,
f1: focal length of the first group,
It is.

  Conditional expression (2) defines a preferred power ratio of the fifth group. If the lower limit of conditional expression (2) is exceeded, the power of the fifth lens group becomes strong, so that the image plane fluctuation on the close side becomes large and its correction becomes difficult. If the upper limit of conditional expression (2) is exceeded, the power of the fifth lens group becomes weak and the amount of movement during focusing increases. As a result, it is necessary to increase the overall power of the zoom lens in order to ensure a movable range, and it becomes difficult to correct aberrations generated at that time, particularly spherical aberrations in the fourth group.

It is more desirable to satisfy the following conditional expression (2a).
3.5 <f5 / f1 <4.5 (2a)
This conditional expression (2a) defines a more preferable condition range based on the above viewpoints, etc., among the condition ranges defined by the conditional expression (2). Therefore, the above effect can be further increased preferably by satisfying conditional expression (2a).

It is desirable to satisfy the following conditional expression (3).
0.05 <| m5 / m4 | <0.4 (3)
However,
m5: Amount of movement during zooming from the wide end to the tele end of the fifth lens unit,
m4: the amount of movement when zooming from the wide end to the tele end of the fourth lens unit,
It is.

  Conditional expression (3) defines a preferable amount of movement of the fifth group in zooming from the wide end to the tele end. Assuming that the focus driving of the fifth group is performed by an electric means such as a motor, if the movement amount of the fifth group becomes large, there is a possibility that interference with the fourth group occurs during zooming. In other words, when it is assumed that zooming is performed manually, the fifth group is driven with focus by a motor. Therefore, if the fifth group is not interlocked with the manual zoom mechanism, the zoom movement amount of the fifth group manually is large. There is a risk of interference between the fourth group and the fifth group. In order to avoid this interference, the fifth group needs to be interlocked by both the motor drive and the manual zoom mechanism, which causes a complicated mechanism design.

  If the amount of movement of the fifth group during zooming is set within the range of conditional expression (3), it becomes easy to avoid interference during zooming. If the lower limit of conditional expression (3) is exceeded, the amount of movement of the fifth lens group will be small, and it will be difficult to correct the curvature of field by the movement of the fifth lens group. If the upper limit of conditional expression (3) is exceeded, the amount of movement of the fifth group becomes too large and interferes with the fourth group during zooming, so that it becomes necessary to provide an interlocking mechanism.

It is more desirable to satisfy the following conditional expression (3a)
0.1 <| m5 / m4 | <0.2 (3a)
This conditional expression (3a) defines a more preferable condition range based on the above viewpoints, etc., among the condition ranges defined by the conditional expression (3). Therefore, the above effect can be further increased preferably by satisfying conditional expression (3a).

It is desirable to satisfy the following conditional expression (4).
-2.5 <f2_4w / f1 <-1.6 (4)
However,
f2 — 4w: the combined focal length from the second group to the fourth group at the wide end,
f1: focal length of the first group,
It is.

  Conditional expression (4) defines the ratio of the combined power at the wide end from the second group to the fourth group. That is, in the present invention, main zooming is performed from the first group to the fourth group, and a power range desirable for correcting the aberration is defined by the conditional expression (4). When the lower limit of conditional expression (4) is exceeded, the combined power from the second group to the fourth group becomes weak, and the total length tends to increase. In order to suppress the increase in the total length, it is necessary to increase the powers of the fifth group and the sixth group, so that it is particularly difficult to correct astigmatism generated in the sixth group. If the upper limit of conditional expression (4) is exceeded, the combined power from the second group to the fourth group becomes strong, the generation of spherical aberration becomes too large, and correction thereof becomes difficult.

It is more desirable to satisfy the following conditional expression (4a).
-2.1 <f2_4w / f1 <-1.7 (4a)
The conditional expression (4a) defines a more preferable condition range based on the above viewpoints, etc., among the condition ranges defined by the conditional expression (4). Therefore, the above effect can be further increased preferably by satisfying conditional expression (4a).

  It is desirable that the second group and the fourth group move while maintaining a constant interval during zooming. The second group and the fourth group have strong positive power, and the sensitivity of parallel eccentricity and inclination eccentricity tends to be relatively strong. When the eccentricity occurs, an asymmetry of the image plane position off the axis is generated. Therefore, it is necessary to adopt a lens barrel configuration so that the eccentricity becomes as small as possible. In the configuration in which the distance between the second group and the fourth group changes relatively during zooming, it is necessary to configure the second group and the fourth group as separate parts as the lens barrel configuration, and compensate for the relative eccentricity. There are considerable difficulties in processing accuracy. If the second group and the fourth group are moved together during zooming, it is possible to configure the lens barrel structure as a single component, which is preferable for accuracy correction and can provide a high-performance product. It becomes.

  It is desirable that a diaphragm is provided on the image side of the second group, and the diaphragm moves integrally with the second group during zooming. The zoom lens according to the present invention mainly assumes an imaging lens for a camera using a solid-state imaging device, but a microlens is used on the front surface in order to increase the light collection efficiency to the solid-state imaging device. There are many. As a characteristic of the microlens, problems such as vignetting and incident on an adjacent pixel occur when the light does not enter from a certain pupil position. For this reason, it is necessary to design an optical system normally used for a solid-state imaging device so as to have a certain telecentricity. In order to ensure telecentricity, it is necessary to set the exit pupil position closer to the object side. As in the first, second, fourth, and fifth embodiments (Examples 1, 2, 4, and 5), which will be described later, if the stop is disposed on the image side of the second group, the exit pupil position is set on the object side It becomes possible to set to.

In order to ensure telecentricity, it is more desirable to satisfy the following conditional expression (5).
−5.5 <f6 / f1 <−1.8 (5)
However,
f6: focal length of the sixth group,
f1: focal length of the first group,
It is.

  When the final lens group satisfies the conditional expression (5), it is possible to achieve downsizing while the lens back is relatively short. If the lower limit of conditional expression (5) is exceeded, the power of the positive lens in the sixth group becomes weak, so that it is necessary to lengthen the lens back in order to ensure telecentricity. As a result, the power of the positive lens in the fourth group is increased, and it becomes difficult to suppress the variation in curvature during zooming that occurs in the fourth group. If the upper limit of conditional expression (5) is exceeded, the power of the positive lens in the sixth group becomes too strong, making it difficult to ensure proper telecentricity.

It is more desirable to satisfy the following conditional expression (5a).
-2.6 <f6 / f1 <-2 (5a)
This conditional expression (5a) defines a more preferable condition range based on the above viewpoints, etc., among the condition ranges defined by the conditional expression (5). Therefore, the above effect can be further increased preferably by satisfying conditional expression (5a).

  Further, it is desirable in terms of the lens barrel configuration that the sixth group is fixed during zooming. Since the sixth group is a lens group on the most image side, a fixed group is preferable in terms of the lens barrel configuration. In the lens barrel configuration of the interchangeable lens, the mount for the body, the electric substrate, and the like are laid out on the image side, so the space for installing the mechanism configuration is limited. It is more effective for correcting the telecentricity that the sixth group is located closer to the image side. For this purpose, a configuration in which the zoom lens is fixed during zooming is desirable.

  The zoom lens according to the present invention is suitable for use as an imaging lens for a digital device with an image input function (for example, a digital camera). By combining this with an imaging device or the like, an image of a subject is optically captured. Thus, an imaging optical device that outputs an electrical signal can be configured. The imaging optical device is an optical device that constitutes a main component of a camera used for still image shooting and moving image shooting of a subject, for example, a zoom lens that forms an optical image of an object in order from the object (that is, subject) side, And an imaging device that converts an optical image formed by the zoom lens into an electrical signal. The zoom lens having the above-described characteristic configuration is arranged so that the optical image of the subject is formed on the light receiving surface (that is, the imaging surface) of the image sensor, thereby achieving high performance at a small size and low cost. An imaging optical device and a digital device including the imaging optical device can be realized.

  Examples of digital devices with an image input function include cameras such as digital cameras, video cameras, surveillance cameras, in-vehicle cameras, videophone cameras, etc., and personal computers, mobile terminals (for example, mobile phones, mobile computers, etc.) Small and portable information device terminals), peripheral devices (scanners, printers, etc.), cameras incorporated in or external to other digital devices, and the like. As can be seen from these examples, it is possible not only to configure a camera by using an imaging optical device, but also to add a camera function by mounting the imaging optical device on various devices. For example, a digital device with an image input function such as a mobile phone with a camera can be configured.

  FIG. 46 shows a schematic configuration example of a digital device DU having an image input function in a schematic cross section. The imaging optical device LU mounted on the digital device DU shown in FIG. 46 sequentially forms a zoom lens ZL (AX: light) that forms an optical image (image plane) IM of the object so as to be variable in order from the object (namely, subject) side. Axis), a plane parallel plate PT (cover glass of the image sensor SR; corresponding to an optical filter such as an optical low-pass filter and an infrared cut filter arranged as necessary), and a light receiving surface by a zoom lens ZL And an image sensor SR that converts an optical image IM formed on the SS into an electrical signal. When a digital device DU with an image input function is constituted by this imaging optical device LU, the imaging optical device LU is usually arranged inside the body, but when necessary to realize the camera function, a form as necessary is adopted. Is possible. For example, the unitized imaging optical device LU can be configured to be detachable or rotatable with respect to the main body of the digital device DU.

  As the image sensor SR, for example, a solid-state image sensor such as a CCD image sensor or a CMOS image sensor having a plurality of pixels is used. Since the zoom lens ZL is provided so that the optical image IM of the subject is formed on the light receiving surface SS which is a photoelectric conversion unit of the image sensor SR, the optical image IM formed by the zoom lens ZL is the image sensor. It is converted into an electric signal by SR.

  The digital device DU includes a signal processing unit 1, a control unit 2, a memory 3, an operation unit 4, a display unit 5 and the like in addition to the imaging optical device LU. The signal generated by the image sensor SR is subjected to predetermined digital image processing, image compression processing, and the like as required by the signal processing unit 1 and recorded as a digital video signal in the memory 3 (semiconductor memory, optical disk, etc.) In some cases, it is transmitted to other devices via a cable or converted into an infrared signal or the like (for example, a communication function of a mobile phone). The control unit 2 is composed of a microcomputer, and controls functions such as a shooting function (still image shooting function, moving image shooting function, etc.) and an image reproduction function; control of a lens moving mechanism for zooming, focusing, camera shake correction, etc. Do it intensively. For example, the control unit 2 controls the imaging optical device LU so as to perform at least one of still image shooting and moving image shooting of a subject. The display unit 5 includes a display such as a liquid crystal monitor, and displays an image using an image signal converted by the image sensor SR or image information recorded in the memory 3. The operation unit 4 is a part including operation members such as an operation button (for example, a release button) and an operation dial (for example, a shooting mode dial), and transmits information input by the operator to the control unit 2.

  The zoom lens ZL has a large-aperture / super-wide-angle zoom configuration composed of six groups of negative positive, negative, positive and negative. Further, each group moves along the optical axis AX to change the distance between the groups to perform zooming (that is, zooming), and the fifth group moves along the optical axis AX to perform focusing ( Focusing on a short-distance object is performed by moving the fifth group toward the image side.), And an optical image IM is formed on the light receiving surface SS of the image sensor SR.

  Here, the specific optical configuration of the zoom lens ZL will be described in more detail with reference to the first to fifth embodiments. 1, 10, 19, 28, and 37 are lens configuration diagrams corresponding to the zoom lenses ZL constituting the first to fifth embodiments, respectively, and include a wide end (W) and a tele end ( The lens arrangement at T) is shown in optical section. The arrows m1, m2, m3, m4, m5, and m6 in the lens configuration diagram indicate the first group Gr1, the second group Gr2, the third group Gr3, and the third group Gr3 in zooming from the wide end (W) to the tele end (T). The movements of the fourth group Gr4, the fifth group Gr5, and the sixth group Gr6 are schematically shown.

  In the first to fifth embodiments (FIGS. 1, 10, 19, 28, and 37), the first group Gr1 to the fifth group Gr5 are moving groups, and the sixth group Gr6 is a fixed group. is there. Accordingly, the first group Gr1 to the fifth group Gr5 move during zooming, and the sixth group Gr6 is fixed at the zoom position. However, the second group Gr2 and the fourth group Gr4 move together during zooming, and the third group Gr3 moves independently of it.

  The fifth group Gr5 is a focus group, and moves to the image side during focusing on a short-distance object, as indicated by an arrow mF. The fifth group Gr5 is composed of one negative meniscus lens convex on the object side, and both lens surfaces are spherical. In the first, second, fourth and fifth embodiments, the stop ST is located on the image side of the second group Gr2, and moves together with the second group Gr2 during zooming. In the third embodiment, the stop ST is located on the image side of the third group Gr3, and moves together with the third group Gr3 during zooming.

  Hereinafter, the configuration and the like of the zoom lens embodying the present invention will be described more specifically with reference to the construction data of the examples. Examples 1 to 5 (EX1 to 5) listed here are numerical examples corresponding to the first to fifth embodiments, respectively, and are optical configuration diagrams showing the first to fifth embodiments. (FIG. 1, FIG. 10, FIG. 19, FIG. 28, FIG. 37) show the lens configurations of the corresponding Examples 1 to 5, respectively.

In the construction data of each embodiment, as surface data, in order from the left column, the surface number, the radius of curvature r (mm), the axial upper surface distance d (mm), and the refractive indexes nd and d regarding the d-line (wavelength 587.56 nm). The Abbe number vd for the line is shown. A surface with * in the surface number is an aspheric surface, and the surface shape is defined by the following expression (AS) using a local orthogonal coordinate system (x, y, z) with the surface vertex as the origin. . As aspheric data, an aspheric coefficient or the like is shown. It should be noted that the coefficient of the term not described in the aspherical data of each example is 0, and E−n = × 10 ⁻ⁿ for all data.
z = (CURV · h ² ) / [1 + √ {1− (1 + K) · CURV ² · h ² }] + A · h ⁴ + B · h ⁶ + C · h ⁸ + D · h ¹⁰ + E · h ¹² + F · h ¹⁴ ... (AS)
However,
h: height in the direction perpendicular to the z axis (optical axis AX) (h ² = x ² + y ² ),
z: the amount of sag in the direction of the optical axis AX at the position of the height h (based on the surface vertex),
CURV: curvature at the surface apex (the reciprocal of the radius of curvature r),
K: conic constant,
A, B, C, D, E, F: aspheric coefficient,
It is.

  As various data, zoom ratio is shown, focal length (fL, mm), angle of view (2ω, °), back focus (BF, mm), total lens length (TL, mm), F number (Fno.). , And image height (Y ′, mm) are shown for each focal length state W, M, T. Variable distance data (di: variable axial upper surface distance, i: surface number, d0: subject distance) in the subject infinite state and closest subject state are shown for each focal length state, and zoom lens group data for each lens group is shown. Indicates the focal length (mm). Table 1 shows values corresponding to the conditional expressions of the respective examples. The back focus expresses the distance from the lens final surface to the paraxial image plane in terms of air length, and the total lens length is the distance from the lens front surface to the lens final surface plus the back focus. .

  2, FIG. 11, FIG. 20, FIG. 29, and FIG. 38 are longitudinal aberration diagrams for infinite subjects corresponding to Examples 1 to 5 (EX1 to EX5), respectively. Various aberrations in the intermediate focal length state (M, ∞) and the telephoto end (T, ∞) (in order from the left are spherical aberration, astigmatism, and distortion aberration) are shown. 6, FIG. 15, FIG. 24, FIG. 33, and FIG. 42 are longitudinal aberration diagrams with respect to the closest subject corresponding to Examples 1 to 5 (EX1 to EX5), respectively, and wide end (W, N), Various aberrations at the intermediate focal length state (M, N) and at the telephoto end (T, N) (in order from the left are spherical aberration, astigmatism, and distortion aberration) are shown.

  In longitudinal aberration diagrams, (A), (D), and (G) are spherical aberration diagrams, (B), (E), and (H) are astigmatism diagrams, and (C), (F), and (I) are It is a distortion aberration figure. In the spherical aberration diagram, the amount of spherical aberration with respect to the d-line (wavelength 587.56 nm) indicated by the solid line is represented by the amount of deviation (unit: mm) in the optical axis AX direction from the paraxial image plane, and the vertical axis represents the pupil. Is a value obtained by normalizing the incident height of the lens by the maximum height (that is, the relative pupil height). In the astigmatism diagram, the broken line represents the tangential image plane with respect to the d-line, and the solid line represents the sagittal image plane with respect to the d-line in terms of the deviation (unit: mm) in the optical axis AX direction from the paraxial image plane. The axis represents the image height (IMG HT, unit: mm). In the distortion diagrams, the horizontal axis represents distortion (unit:%) with respect to the d-line, and the vertical axis represents image height (IMG HT, unit: mm). Note that the maximum value of the image height IMG HT corresponds to the maximum image height Y ′ on the image plane IM (half the diagonal length of the light receiving surface SS of the image sensor SR).

  3 to 5 are lateral aberration diagrams with respect to an infinite object at the wide end (W, ∞), the intermediate focal length state (M, ∞), and the tele end (T, ∞) of Example 1 (EX1). 7 to 9 are lateral aberration diagrams with respect to the closest subject at the wide end (W, N), the intermediate focal length state (M, N), and the tele end (T, N) in Example 1 (EX1). 12 to 14 are lateral aberration diagrams with respect to an infinite object at the wide end (W, ∞), the intermediate focal length state (M, ∞), and the tele end (T, ∞) in Example 2 (EX2). 16 to 18 are lateral aberration diagrams with respect to the closest subject at the wide end (W, N), the intermediate focal length state (M, N), and the tele end (T, N) in Example 2 (EX2). FIGS. 21 to 23 are lateral aberration diagrams with respect to an object at infinity at the wide end (W, ∞), the intermediate focal length state (M, ∞), and the tele end (T, ∞) in Example 3 (EX3). FIGS. 25 to 27 are lateral aberration diagrams for the closest subject at the wide end (W, N), the intermediate focal length state (M, N), and the tele end (T, N) in Example 3 (EX3). FIGS. 30 to 32 are lateral aberration diagrams for the infinite object at the wide end (W, ∞), the intermediate focal length state (M, ∞), and the tele end (T, ∞) in Example 4 (EX4). 34 to 36 are lateral aberration diagrams with respect to the closest subject at the wide end (W, N), the intermediate focal length state (M, N), and the tele end (T, N) in Example 4 (EX4). 39 to 41 are lateral aberration diagrams with respect to an infinite object at the wide end (W, ∞), the intermediate focal length state (M, ∞), and the tele end (T, ∞) in Example 5 (EX5). 43 to 45 are lateral aberration diagrams with respect to the closest subject at the wide end (W, N), the intermediate focal length state (M, N), and the tele end (T, N) in Example 5 (EX5).

  In the lateral aberration diagrams, (A) to (E) show the lateral aberration with a tangential beam, and (F) to (J) show the lateral aberration with a sagittal beam. Further, the lateral aberration (mm) at the image height ratio (half angle of view ω °) represented by RELATIVE FIELD HEIGHT is shown for the d-line (wavelength 587.56 nm). The image height ratio is a relative image height obtained by normalizing the image height with the maximum image height Y ′.

Example 1
Unit: mm
Surface data surface number rd nd vd
1 * 79.233 2.00 1.69350 53.19
2 * 12.750 7.22
3 137.602 1.20 1.72916 54.67
4 22.374 0.20 1.52030 51.10
5 * 29.029 4.32
6 -188.011 1.54 1.61800 63.40
7 28.553 1.94
8 27.939 4.00 1.78472 25.72
9 690.445 20.43 (variable)
10 25.598 1.20 1.84666 23.78
11 14.610 3.09 1.54814 45.82
12 -212.469 0.32
13 157.076 1.81 1.70154 41.15
14 -45.628 1.00
15 (Aperture) ∞ 3.45 (Variable)
16 -17.925 0.81 1.84666 23.78
17 72.044 2.33 1.92286 20.88
18 -25.789 8.54 (variable)
19 48.756 3.57 1.49700 81.55
20 -15.175 0.80 1.83481 42.72
21 -22.032 0.10
22 62.181 0.80 1.83400 37.35
23 14.052 3.35 1.49700 81.55
24 -68.054 3.70 (variable)
25 46.803 0.80 1.83481 42.72
26 24.345 2.31 (variable)
27 * 20.555 4.24 1.67790 54.89
28 * 124.764 15.0 1
Image plane ∞

Aspheric data 1st surface
CURV = 0.01262103
K = 13.739368
A = -1.11296E-05
B = 1.34353E-07
C = -3.04165E-10
D = -4.67021E-13
E = 2.67396E-15
F = -2.83699E-18

Second side
CURV = 0.07842989
K = -0.145760
A = -9.09069E-05
B = 7.30580E-08
C = 1.17070E-09
D = -9.14845E-12
E = -6.00042E-15
F = -1.66231E-17

5th page
CURV = 0.03444843
K = 0.000000
A = 8.06168E-05
B = -2.68663E-07
C = 2.08619E-09
D = -1.21987E-11
E = 0.00000E + 00
F = 0.00000E + 00

27th page
CURV = 0.04865101
K = 0.000000
A = -5.27221E-06
B = -2.68468E-07
C = 1.76335E-09
D = -3.62503E-12
E = -2.32478E-14
F = 0.00000E + 00

28th page
CURV = 0.00801514
K = 0.000000
A = 1.67198E-05
B = -4.71716E-07
C = 3.76851E-09
D = -1.45311E-11
E = 1.25269E-15
F = 0.00000E + 00

Various data zoom ratio: 2.12
(W) (M) (T)
fL 8.22 11.99 17.42
2ω 105.45 84.01 63.60
BF 15.01 15.04 15.01
TL 100.08 95.84 99.05
Fno 2.9 2.9 2.9
Y '10.90 10.90 10.90

Variable interval data (object distance: infinite)
(W) (M) (T)
d0 ∞ ∞ ∞
d9 20.427 8.445 0.800
d15 3.447 6.228 10.987
d18 8.540 5.759 1.000
d24 3.699 10.418 19.209
d26 2.313 3.316 5.41 3

Variable interval data (Subject distance: closest)
(W) (M) (T)
d0 150 154 151
d9 20.427 8.445 0.800
d15 3.447 6.228 10.987
d18 8.540 5.759 1.000
d24 4.775 12.625 23.824
d26 1.238 1.108 0.79 8

Zoom lens group data group Focal length Group 1 -15.38
Second group 29.40
3rd group -131.08
Group 4 44.52
Group 5 -61.78
Group 6 35.71

Example 2
Unit: mm
Surface data surface number rd nd vd
1 * 75.931 2.00 1.69350 53.19
2 * 12.495 6.65
3 60.272 1.20 1.72916 54.67
4 19.605 0.20 1.52030 51.10
5 * 23.981 7.50
6 -45.772 2.10 1.61800 63.40
7 54.688 0.58
8 38.643 3.19 1.78472 25.72
9 -130.672 21.57 (variable)
10 44.427 0.80 1.84666 23.78
11 17.521 2.32 1.54814 45.82
12 58.987 0.10
13 24.752 2.81 1.70154 41.15
14 -54.014 1.00
15 (Aperture) ∞ 6.26 (Variable)
16 -18.466 0.81 1.84666 23.78
17 22.007 3.21 1.92286 20.88
18 -29.041 6.03 (variable)
19 * 1196.723 1.50 1.58913 61.25
20 -51.955 0.40
21 44.793 3.69 1.49700 81.55
22 -13.796 0.80 1.83481 42.72
23 -23.637 0.10
24 -57.226 0.80 1.83400 37.35
25 20.009 3.69 1.49700 81.55
26 -26.848 3.89 (variable)
27 41.742 0.80 1.83481 42.72
28 23.088 2.37 (variable)
29 * 21.934 4.58 1.67790 54.89
30 * 238.241 14.8 0
Image plane ∞

Aspheric data 1st surface
CURV = 0.01316991
K = 7.482037
A = 0.459185E-05
B = 0.541045E-08
C = 0.351911E-10
D = -0.549133E-12
E = 0.180605E-14
F = -0.170436E-17

Second side
CURV = 0.08003214
K = -0.210426
A = -0.683162E-04
B = 0.111033E-06
C = -0.189884E-08
D = 0.851970E-11
E = -0.572875E-13
F = 0.124260E-15

5th page
CURV = 0.04169993
K = 0.000000
A = 0.688334E-04
B = -0.271848E-06
C = 0.439023E-08
D = -0.246342E-10

19th page
CURV = 0.00083562
K = 0.000000
A = -0.104520E-04
B = 0.612169E-07
C = -0.504967E-09
D = 0.602189E-11

29th page
CURV = 0.04559130
K = 0.000000
A = -0.521893E-05
B = -0.135225E-06
C = -0.228595E-09
D = 0.875987E-11
E = -0.606477E-13
F = 0.000000E + 00

30th page
CURV = 0.00419742
K = 0.000000
A = 0.119493E-04
B = -0.387829E-06
C = 0.278076E-08
D = -0.108982E-10
E = -0.904192E-14
F = 0.000000E + 00

Various data zoom ratio: 2.12
(W) (M) (T)
fL 8.22 12.01 17.42
2ω 105.45 83.93 63.59
BF 14.80 14.83 14.80
TL 105.76 101.66 105.57
Fno 2.9 2.9 2.9
Y '10.90 10.90 10.90

Variable interval data (object distance: infinite)
(W) (M) (T)
d0 ∞ ∞ ∞
d9 21.573 8.961 0.800
d15 6.261 8.398 11.292
d18 6.030 3.894 1.000
d26 3.893 11.294 21.185
d28 2.372 3.452 5.66 5

Variable interval data (Subject distance: closest)
(W) (M) (T)
d0 144 148 144
d9 21.573 8.961 0.800
d15 6.261 8.398 11.292
d18 6.030 3.894 1.000
d26 5.044 13.658 26.123
d28 1.222 1.089 0.72 7

Zoom lens group data group Focal length Group 1 -15.30
Second group 29.93
3rd group -130.58
Group 4 48.13
Group 5 -63.12
Group 6 35.33

Example 3
Unit: mm
Surface data surface number rd nd vd
1 * 87.083 1.98 1.70000 55.00
2 * 10.875 3.91
3 * 18.745 1.90 1.80007 46.87
4 * 15.155 6.56
5 -45.989 2.44 1.70000 55.00
6 149.680 0.20
7 23.325 3.50 1.85878 28.00
8 33.333 13.35 (variable)
9 31.158 0.80 1.80486 22.76
10 14.917 2.96 1.59416 38.11
11 -197.602 0.10
12 26.343 2.23 1.77239 49.70
13 -173.593 3.50 (variable)
14 -41.118 0.70 1.81470 43.25
15 41.376 0.62
16 1281.624 0.50 1.88300 40.80
17 18.344 2.18 1.75845 23.95
18 -52.109 0.60
19 (Aperture) ∞ 9.16 (Variable)
20 91.992 4.02 1.49700 81.55
21 -11.515 0.90 1.70789 28.12
22 -20.009 0.10
23 20.356 0.80 1.87115 33.28
24 14.858 4.24 1.49700 81.55
25 -98.534 1.76 (variable)
26 41.386 0.80 1.72829 27.13
27 21.230 3.66 (variable)
28 * 25.880 3.40 1.48749 70.44
29 763.094 15.4 9
Image plane ∞

Aspheric data 1st surface
CURV = 0.01148336
K = -5.603084
A = 2.80282E-05
B = -5.29063E-08
C = 5.24859E-11
D = 4.71350E-15

Second side
CURV = 0.09195456
K = -0.598706
A = -7.94066E-05
B = 2.33534E-07
C = -1.02174E-09
D = -4.54489E-12

Third side
CURV = 0.05334825
K = 0.000000
A = -1.67460E-05
B = -1.32167E-07
C = -3.41011E-10
D = -1.40790E-12

4th page
CURV = 0.06598568
K = 0.000000
A = 8.24175E-05
B = -2.12119E-08
C = -7.29027E-10
D = 6.39893E-12

28th page
CURV = 0.03864009
K = 0.000000
A = -2.47977E-05
B = 1.19542E-07
C = -1.37453E-09
D = 5.26763E-12

Various data zoom ratio: 2.12
(W) (M) (T)
fL 8.20 11.96 17.37
2ω 105.58 84.16 63.73
BF 15.49 15.55 15.49
TL 92.37 89.82 92.51
Fno 2.9 2.9 2.9
Y '10.85 10.85 10.85

Variable interval data (object distance: infinite)
(W) (M) (T)
d0 ∞ ∞ ∞
d8 13.345 5.873 0.800
d13 3.503 7.855 11.960
d19 9.158 4.805 0.700
d25 1.762 5.540 13.298
d27 3.659 4.753 4.82 2

Variable interval data (Subject distance: closest)
(W) (M) (T)
d0 158 160 157
d8 13.345 5.873 0.800
d13 3.503 7.855 11.960
d19 9.158 4.805 0.700
d25 2.490 7.020 16.573
d27 2.932 3.273 1.54 6

Zoom lens group data group Focal length Group 1 -11.98
Second group 21.22
3rd group -33.32
Group 4 22.29
Group 5 -60.87
Group 6 54.87

Example 4
Unit: mm
Surface data surface number rd nd vd
1 34.972 1.70 1.78402 48.41
2 12.884 6.00
3 * 27.027 2.50 1.75155 51.87
4 * 14.031 6.93
5 -44.661 2.40 1.72916 54.67
6 55.696 0.10 1.51380 52.97
7 * 50.113 2.45
8 39.060 3.43 1.78472 25.72
9 -121.733 22.66 (variable)
10 29.156 0.80 1.84666 23.78
11 17.514 4.06 1.54814 45.82
12 -78.705 0.26
13 321.349 1.64 1.70154 41.15
14 -64.906 1.00
15 (Aperture) ∞ 3.30 (Variable)
16 -20.927 0.80 1.51680 64.20
17 -37.413 0.60
18 60.351 0.75 1.83481 42.72
19 22.623 2.50 1.62230 53.17
20 -204.803 8.51 (variable)
21 165.362 3.17 1.49700 81.55
22 -16.290 0.80 1.83481 42.72
23 -23.311 0.10
24 51.013 0.80 1.83400 37.35
25 15.212 3.25 1.49700 81.55
26 -78.408 3.51 (variable)
27 36.141 0.80 1.83481 42.72
28 20.537 2.11 (variable)
29 * 20.549 4.08 1.67790 54.89
30 * 125.000 15.0 8
Image plane ∞

Aspheric data 3rd surface
CURV = 0.03700000
K = 0.000000
A = 1.80823E-04
B = -1.76441E-06
C = 1.36220E-08
D = -5.85875E-11
E = 1.14789E-13
F = -7.60640E-18

4th page
CURV = 0.07127308
K = 0.000000
A = 1.70888E-04
B = -2.58692E-06
C = 1.57745E-08
D = -6.12314E-11
E = 0.00000E + 00
F = 0.00000E + 00

7th page
CURV = 0.01995492
K = 0.000000
A = 9.19851E-06
B = 1.35424E-07
C = -1.34501E-09
D = 6.65617E-12
E = 1.55707E-24
F = -1.92140E-28

29th page
CURV = 0.04866314
K = 0.000000
A = -5.13239E-06
B = -6.34169E-08
C = 5.03313E-10
D = -5.39179E-12
E = 0.00000E + 00
F = 0.00000E + 00

30th page
CURV = 0.00800000
K = 0.000000
A = 1.20867E-05
B = -2.03339E-07
C = 2.12433E-09
D = -1.78927E-11
E = 3.58232E-14
F = 0.00000E + 00

Various data zoom ratio: 2.12
(W) (M) (T)
fL 8.22 11.99 17.42
2ω 105.45 84.02 63.61
BF 15.08 15.12 15.07
TL 106.09 101.16 104.33
Fno 2.9 2.9 2.9
Y '10.85 10.85 10.85

Variable interval data (object distance: infinite)
(W) (M) (T)
d0 ∞ ∞ ∞
d9 22.665 9.473 0.800
d15 3.301 6.394 10.611
d20 8.510 5.417 1.200
d26 3.511 10.809 20.716
d28 2.114 3.037 5.02 4

Variable interval data (Subject distance: closest)
(W) (M) (T)
d0 144 149 146
d9 22.665 9.473 0.800
d15 3.301 6.394 10.611
d20 8.510 5.417 1.200
d26 4.553 12.939 25.177
d28 1.071 0.907 0.56 3

Zoom lens group data group Focal length Group 1 -15.55
Second group 32.26
3rd group -328.80
Group 4 53.04
Group 5 -58.34
Group 6 35.71

Example 5
Unit: mm
Surface data surface number rd nd vd
1 * 52.220 1.70 1.69350 53.19
2 * 10.081 7.26
3 28.445 1.20 1.69680 55.46
4 18.076 0.10 1.52030 51.10
5 * 16.591 5.98
6 -40.065 1.06 1.69680 55.46
7 130.708 0.73
8 38.895 3.50 1.78472 25.72
9 -109.203 21.97 (variable)
10 26.977 0.80 1.84666 23.78
11 16.516 3.18 1.54814 45.82
12 -82.127 0.21
13 245.045 1.55 1.70154 41.15
14 -76.459 1.00
15 (Aperture) ∞ 2.39 (Variable)
16 -21.760 0.80 1.51680 64.20
17 -39.615 0.60
18 67.238 0.75 1.83481 42.72
19 23.468 2.42 1.62230 53.17
20 -143.169 9.10 (variable)
21 ∞ 2.96 1.49700 81.55
22 -15.857 0.80 1.83481 42.72
23 -23.338 0.10
24 45.963 0.80 1.83400 37.35
25 15.884 3.24 1.49700 81.55
26 -58.588 3.44 (variable)
27 43.290 0.80 1.83481 42.72
28 22.799 1.99 (variable)
29 * 20.665 4.02 1.67790 54.89
30 130.009 15.2 0
Image plane ∞

Aspheric data 1st surface
CURV = 0.01914976
K = 5.844733
A = 1.72010E-06
B = 1.13630E-08
C = -2.07244E-10
D = 1.20596E-13
E = 1.47039E-15
F = -3.27849E-18

Second side
CURV = 0.09919719
K = -0.430925
A = -3.36213E-05
B = -1.34005E-08
C = 4.27108E-09
D = -5.11414E-11
E = 1.86431E-13
F = -1.70694E-17

5th page
CURV = 0.06027273
K = 0.000000
A = 2.42786E-05
B = -4.16603E-07
C = 1.84618E-09
D = -1.76082E-11

29th page
CURV = 0.04839075
K = 0.000000
A = -1.42471E-05
B = 3.18352E-08
C = -1.91694E-10
D = 4.51101E-13

Various data zoom ratio: 2.12
(W) (M) (T)
fL 8.22 11.99 17.42
2ω 105.45 84.02 63.61
BF 15.20 15.25 15.21
TL 99.66 95.06 98.38
Fno 2.9 2.9 2.9
Y '10.85 10.85 10.85

Variable interval data (object distance: infinite)
(W) (M) (T)
d0 ∞ ∞ ∞
d9 21.971 9.208 0.800
d15 2.385 5.725 10.281
d20 9.096 5.756 1.200
d26 3.438 10.644 20.485
d28 1.989 2.893 4.82 7

Variable interval data (Subject distance: closest)
(W) (M) (T)
d0 150 155 152
d9 21.971 9.208 0.800
d15 2.385 5.725 10.281
d20 9.096 5.756 1.200
d26 4.459 12.737 24.880
d28 0.968 0.799 0.43 3

Zoom lens group data group Focal length Group 1 -15.50
2nd group 32.00
3rd group -378.95
Group 4 49.47
Group 5 -58.74
Group 6 35.71

DU Digital equipment LU Imaging optical device ZL Zoom lens Gr1 1st group Gr2 2nd group Gr3 3rd group Gr4 4th group Gr5 5th group Gr6 6th group ST Aperture (aperture stop)
SR Image sensor SS Photosensitive surface (imaging surface)
IM image plane (optical image)
AX optical axis 1 signal processing unit 2 control unit 3 memory 4 operation unit 5 display unit

Claims (8)

In order from the object side, a first group having negative power, a second group having positive power, a third group having negative power, a fourth group having positive power, and a fifth group having negative power, A zoom lens comprising a sixth group having positive power, and performing zooming by changing the interval between the groups, and focusing on a short-distance object by moving the fifth group to the image side The zoom lens is characterized in that the fifth group is composed of a single lens that satisfies the following conditional expression (1):
0.2 <(CR1-CR2) / (CR1 + CR2) <0.4 (1)
However,
CR1: radius of curvature of the object side surface,
CR2: radius of curvature of image side surface,
It is. The zoom lens according to claim 1, wherein the following conditional expression (2) is satisfied:
2.5 <f5 / f1 <6 (2)
However,
f5: focal length of the fifth group,
f1: focal length of the first group,
It is. The zoom lens according to claim 1, wherein the following conditional expression (4) is satisfied:
-2.5 <f2_4w / f1 <-1.6 (4)
However,
f2 — 4w: the combined focal length from the second group to the fourth group at the wide end,
f1: focal length of the first group,
It is.   The zoom lens according to any one of claims 1 to 3, wherein the second group and the fourth group move while maintaining a constant interval during zooming.   5. The zoom lens according to claim 1, further comprising a stop on the image side of the second group, wherein the stop moves together with the second group during zooming.   The zoom lens according to claim 1, wherein the zoom lens is an interchangeable lens for a digital camera.   7. A zoom lens according to claim 1, and an image sensor that converts an optical image formed on the light receiving surface into an electrical signal, and a subject on the light receiving surface of the image sensor. An image pickup optical apparatus, wherein the zoom lens is provided so that an optical image is formed.   A digital apparatus comprising the imaging optical device according to claim 7, to which at least one function of still image shooting and moving image shooting of a subject is added.

Images