JP6707987B2 - Large-diameter anti-vibration zoom lens - Google Patents

Description

The present invention relates to a large-diameter anti-vibration zoom lens suitable as a taking lens used in digital cameras, video cameras, and the like.

In recent years, a so-called mirrorless single-lens camera in which a quick return mirror is abolished by providing an electronic viewfinder instead of a conventional single-lens reflex finder as an interchangeable lens type camera has rapidly spread. Mirrorless interchangeable-lens cameras are popular because they do not require a quick return mirror, its drive mechanism, pentaprisms, etc., and can be significantly smaller than conventional single-lens reflex cameras.

As an interchangeable lens for a single-lens reflex camera or a mirrorless single-lens camera, a so-called large-aperture zoom lens with a bright open F value is popular because it has both the convenience of a zoom lens and a bright open F value. Further, in recent years, not only a telephoto lens but also a standard or wide-angle zoom lens has been equipped with an anti-vibration function, and the anti-vibration function has become a standard function in a taking lens. As a zoom lens equipped with a vibration isolation function, there is a zoom lens having a five-group configuration described in Patent Document 1 and Patent Document 2, for example. The zoom lens described in Patent Literature 1 has 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 negative lens group in order from the object side. It is composed of a fourth lens group with a refractive power and a fifth lens group with a positive refractive power. Each lens group moves during zooming from the wide-angle end to the telephoto end, and the second lens group moves during focusing from infinity to close range. It is configured to move to the object side along the optical axis. In addition, the zoom lens described in Patent Document 2 includes, in order from the object side, 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, Consists of a fourth lens unit having a positive refracting power and a fifth lens unit having a negative refracting power. Each lens unit moves during zooming from the wide-angle end to the telephoto end, and the fourth lens is used for focusing from infinity to close range. The group is configured to move to the object side along the optical axis.

JP, 2005-055858, A JP, 2014-238549, A

The zoom lens having a five-group configuration as disclosed in Patent Documents 1 and 2 has a high degree of freedom in group movement during zooming, and it is easy to ensure good imaging performance over the entire zoom range. However, in the zoom lens described in Patent Document 1, the second group is used as the focus group, but there is a problem that the focus group is heavy as an interchangeable lens for a mirrorless single-lens camera. The autofocus of a mirrorless single-lens camera often employs a so-called contrast AF in which a focus lens is finely driven to detect a peak of contrast. Therefore, in order to realize high-speed and smooth contrast AF, it is necessary to make the focus group sufficiently light, but since the focus group is heavy in the zoom lens described in Patent Document 1, it is necessary to realize high-speed and smooth contrast AF. It is difficult.

In the zoom lens described in Patent Document 2, the fourth group is used as the focus group to reduce the weight of the focus group, and high-speed and smooth contrast AF can be realized. However, in the configuration described in Patent Document 2, the incident angle of the light beam having the peripheral field angle on the image pickup element is large. A large-diameter zoom lens with a bright open F value causes a thick light beam. Therefore, if the angle of incidence of a light beam on the image sensor is large, the angle of incidence on the lower ray side becomes too tight, and the image is picked up at the light receiving portion of the image sensor. Therefore, it is required for the large-diameter zoom lens to suppress the incident angle of the light beam having the peripheral field angle to the image pickup element to be small.

The present invention has been made in view of such a situation, and reduces vignetting of peripheral light rays by suppressing the angle of incidence of light rays on the image sensor while keeping the size small, and smoothing by making the focus group lightweight. It is an object of the present invention to provide a large-diameter anti-vibration zoom lens that can realize high contrast AF, has a small variation in aberrations over the entire shooting area, and has good imaging performance.

In order to solve the above-mentioned problems, a first invention is, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and a positive refractive power. It is composed of a third lens group G3 that moves integrally with the open stop by force, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power, from the wide-angle end to the telephoto end. At the time of zooming, each lens group independently moves toward the object side, the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G2 increase. The distance between G3 decreases, and the distances between the third lens group G3, the fourth lens group G4, and the fifth lens group G5 change , and the fourth lens group G4 moves along the optical axis when focusing from infinity to a short distance. The fifth lens group G5 is composed of a fifth-A lens group G5A having a negative refractive power and a fifth-B lens group G5B having a positive refractive power in order from the object side. A large-diameter anti-vibration zoom lens is provided which is characterized by satisfying the following conditional expressions (1) and (2) by performing image stabilization by moving in a direction perpendicular to the optical axis.
(1) 0.9<EXP/SI<1.8
(2) 0.6<f4/|f5A|<1.3
However,
EXP: Wide-angle end, length from the exit pupil to the image plane when focused on infinity (the direction from the object to the image plane is positive)
SI: Wide-angle end, length from diaphragm to image plane when focused on infinity f4: Focal length of fourth lens group G4 f5A: Focal length of fifth A lens group G5A

A second invention is characterized in that the fifth A lens group G5A is composed of two or less lenses and satisfies the following conditional expressions (3), (4) and (5). It is a zoom lens with a vibration proof.
(3) 0.3<|(1-β5A)βr|<0.9
(4) 0.3<VI/SI<0.8
(5) 1.8<Z1wt/Z5Awt<3.0
However,
β5A: Wide-angle end of the fifth A lens group G5A that is responsible for image stabilization, imaging magnification when focused at infinity βr: Wide-angle end of the group closer to the image plane than the fifth A lens group G5A, synthetic combination when focused at infinity Image magnification VI: Length of the 5A-th lens group G5A at the wide-angle end from the most image-side surface to the image surface Z1wt: Movement of the first lens group G1 with respect to the image plane during zooming from the wide-angle end to the telephoto end Amount Z5Awt: Amount of movement of the fifth-A lens unit G5A with respect to the image plane during zooming from the wide-angle end to the telephoto end

The third invention is any one of the first invention or the second invention, wherein the first lens group G1 is composed of two or less lenses and satisfies the following conditional expression (6). It was a large-diameter zoom lens with anti-vibration.
(6) 7.5<f1/|f2|<15.0
However,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

A fourth invention is any one of the first to third inventions, characterized in that the third lens group G3 includes at least one three-lens cement and satisfies the following conditional expression (7). It was a large-diameter zoom lens with anti-vibration.
(7) 1.6<f3/fw<3.2
However,
f3: Focal length of the third lens group G3 fw: Focal length of the entire lens system at the wide angle end and at infinity

A fifth invention is characterized in that the fourth lens group G4 comprises one lens, has at least one aspherical surface, and satisfies the following conditional expression (8). The zoom lens with large-diameter anti-vibration according to any one of the inventions of 4 above.
(8) 0.8<f4/f3<1.6

According to the present invention, it is possible to reduce the vignetting of marginal rays by suppressing the angle of incidence of light rays on the image sensor while maintaining a small size, and to realize smooth contrast AF by reducing the weight of the focus group. It is possible to provide a large-diameter anti-vibration zoom lens with little fluctuation and good imaging performance.

It is a lens block diagram which concerns on Example 1 of the large diameter anti-vibration zoom lens of this invention. 6 is a longitudinal aberration diagram of the zoom lens with large-diameter image stabilization of Example 1 at the wide-angle end and at infinity. FIG. 3 is a lateral aberration diagram at the time of wide-angle end and infinity focusing of the large-diameter anti-vibration zoom lens of Example 1. FIG. FIG. 3 is a lateral aberration diagram of the large-diameter anti-vibration zoom lens of Example 1 at the wide-angle end and at the time of focusing at infinity, when the optical axis is tilted by 0.3° when the image stabilization is performed. FIG. 4 is a lateral aberration diagram at the wide-angle end and at a shooting magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 1. FIG. 4 is a longitudinal aberration diagram at the time of focusing on the middle and infinity of the large-diameter anti-vibration zoom lens of Example 1; FIG. 4 is a lateral aberration diagram at the time of focusing on the middle and infinity of the zoom lens with large-diameter image stabilization of Example 1. FIG. 6 is a lateral aberration diagram of the zoom lens with large-diameter image stabilization of Example 1 when performing image stabilization in a state where the optical axis is tilted by 0.3° at the time of focusing on an intermediate point at infinity. 3 is a lateral aberration diagram at a photographing magnification of 1:40 in the middle of the large-diameter anti-vibration zoom lens of Example 1. FIG. FIG. 3 is a longitudinal aberration diagram of the zoom lens with large-diameter image stabilization of Example 1 at the telephoto end and at infinity. 3 is a lateral aberration diagram at the telephoto end and at infinity of the zoom lens with large-diameter vibration isolation of Example 1. FIG. FIG. 3 is a lateral aberration diagram of the large-diameter anti-vibration zoom lens of Example 1 when performing image stabilization with the optical axis tilted at 0.3° at the telephoto end and at infinity. 3 is a lateral aberration diagram at the telephoto end and at a shooting magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 1. FIG. It is a lens block diagram which concerns on Example 2 of the large diameter anti-vibration zoom lens of this invention. FIG. 9 is a longitudinal aberration diagram of a large-diameter anti-vibration zoom lens of Example 2 at the wide-angle end and at infinity. 9 is a lateral aberration diagram at the wide-angle end and at infinity of the zoom lens with large-diameter image stabilization of Example 2. FIG. FIG. 9 is a lateral aberration diagram of the zoom lens with large-diameter anti-vibration according to Example 2 at the wide-angle end and at the time of focusing at infinity, with the optical axis tilted at 0.3°. 9 is a lateral aberration diagram at the wide-angle end and at a photographing magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 2. FIG. FIG. 6 is a longitudinal aberration diagram at the time of focusing on an intermediate point at infinity of the zoom lens with large-diameter image stabilization of Example 2; FIG. 9 is a lateral aberration diagram at the time of focusing on the middle and infinity of the large-diameter anti-vibration zoom lens of Example 2; FIG. 6 is a lateral aberration diagram of the large-diameter anti-vibration zoom lens of Example 2 when performing image stabilization with the optical axis tilted by 0.3° at the time of focusing in the middle and at infinity. FIG. 9 is a lateral aberration diagram at a photographing magnification of 1:40 in the middle of the large-diameter anti-vibration zoom lens of Example 2; FIG. 6 is a longitudinal aberration diagram of the zoom lens with large-diameter anti-vibration of Example 2 at the telephoto end and at infinity. 9 is a lateral aberration diagram at the telephoto end and at infinity of the zoom lens with large-diameter image stabilization of Example 2. FIG. FIG. 9 is a lateral aberration diagram of the zoom lens with large-diameter anti-vibration according to Example 2 at the telephoto end and at the time of focusing at infinity, when image stabilization is performed with the optical axis inclined by 0.3°. 9 is a lateral aberration diagram at the telephoto end and at a shooting magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 2. FIG. It is a lens block diagram which concerns on Example 3 of the large diameter anti-vibration zoom lens of this invention. FIG. 10 is a longitudinal aberration diagram of a large-diameter anti-vibration zoom lens of Example 3 at the wide-angle end and at infinity. FIG. 9 is a lateral aberration diagram of a zoom lens with large-diameter vibration reduction of Example 3 at the wide-angle end and at infinity. FIG. 9 is a lateral aberration diagram of the zoom lens with large-diameter anti-vibration of Example 3 at the wide-angle end and at the time of focusing at infinity, with the optical axis tilted at 0.3°. FIG. 16 is a lateral aberration diagram at the wide-angle end and at a shooting magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 3; FIG. 6 is a longitudinal aberration diagram at the time of focusing on an intermediate point at infinity of the zoom lens with large-diameter image stabilization of Example 3; FIG. 10 is a lateral aberration diagram at the time of focusing on an intermediate and infinite distance of the large-diameter anti-vibration zoom lens of Example 3; FIG. 9 is a lateral aberration diagram of the zoom lens with large-diameter anti-vibration of Example 3 when performing image stabilization in a state where the optical axis is inclined by 0.3° at the time of focusing in the middle and at infinity. FIG. 16 is a lateral aberration diagram at a middle magnification of a large-diameter anti-vibration zoom lens of Example 3 and at a photographing magnification of 1:40. FIG. 10 is a longitudinal aberration diagram of a zoom lens with large-diameter vibration reduction according to example 3 at the telephoto end and at infinity. FIG. 9 is a lateral aberration diagram at the telephoto end and at infinity of the zoom lens with large aperture image stabilization of Example 3; FIG. 9 is a lateral aberration diagram of the zoom lens with large-diameter anti-vibration according to Example 3 at the telephoto end and at the telephoto end, where the optical axis is tilted by 0.3° when focused at infinity. 16 is a lateral aberration diagram at a telephoto end and a magnification of 1:40 of the zoom lens with large-diameter vibration isolation of Example 3. FIG. It is a lens block diagram which concerns on Example 4 of the large diameter anti-vibration zoom lens of this invention. FIG. 9 is a longitudinal aberration diagram of the zoom lens with large-diameter image stabilization of Example 4 at the wide-angle end and at infinity. 16 is a lateral aberration diagram at the wide-angle end and at infinity of the zoom lens with large-diameter image stabilization of Example 4. FIG. 14 is a lateral aberration diagram of the zoom lens with large-diameter image stabilization of Example 4 at the wide-angle end and at the time of focusing at infinity, when image stabilization is performed with the optical axis tilted at 0.3°. 16 is a lateral aberration diagram at a wide-angle end and a photographing magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 4. FIG. FIG. 8 is a longitudinal aberration diagram at the time of focusing on the middle and infinity of the large-diameter anti-vibration zoom lens of Example 4; FIG. 10 is a lateral aberration diagram at the time of focusing on an intermediate point at infinity of the zoom lens with large-diameter image stabilization of Example 4; FIG. 16 is a lateral aberration diagram of the zoom lens with large-diameter image stabilization of Example 4 when performing image stabilization with the optical axis tilted by 0.3° at the time of focusing on the middle and infinity. FIG. 16 is a lateral aberration diagram at a photographing magnification of 1:40 in the middle of the large-diameter anti-vibration zoom lens of Example 4; FIG. 9 is a longitudinal aberration diagram of a zoom lens with large-diameter vibration reduction of Example 4 at the telephoto end and at infinity. FIG. 9 is a lateral aberration diagram at the telephoto end and at infinity of the zoom lens with large aperture image stabilization according to Example 4; FIG. 9 is a lateral aberration diagram of the large-diameter anti-vibration zoom lens of Example 4 at the telephoto end and at the time of focusing at infinity, when vibration isolation is performed in a state where the optical axis is inclined by 0.3°. FIG. 16 is a lateral aberration diagram at a telephoto end and a magnification of 1:40 of the large-diameter anti-vibration zoom lens of Example 4;

As can be seen from the lens configuration diagrams shown in FIGS. 1, 14, 27, and 40, the large-diameter anti-vibration zoom lens of the present invention includes a first lens group G1 having a positive refractive power in order from the object side. , A second lens group G2 having a negative refractive power, an aperture stop S, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens having a negative refractive power. The fourth lens group G4 is configured to move toward the object side along the optical axis during focusing from infinity to a short distance.

The fifth lens group G5 is composed of, in order from the object side, a 5A lens group G5A having a negative refractive power and a 5B lens group G5B having a positive refractive power, and the 5A lens group G5A moves in a direction perpendicular to the optical axis. Anti-vibration is performed by doing.

Upon zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases, The third lens group G3, the fourth lens group G4, and the fifth lens group G5 are independently movable toward the object side.

As described above, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the third lens group G3 having a positive refractive power are included. It is possible to change the magnification by changing the distance between the second lens group and the third lens group, and it is possible to reduce the zooming load of the focus lens group and the image stabilizing lens group by performing focus and image stabilization on the image surface side of the third lens group. It is possible to reduce the number, and to realize good imaging performance in each focus/anti-vibration state. Further, the fifth lens group G5 having a negative refractive power is composed of the fifth A lens group G5A having a negative refractive power and the fifth B lens group G5B having a positive refractive power, so that the fifth lens group G5 having a negative refractive power has a negative refractive power. The 5A lens group G5A bounces up the light beam having the peripheral field angle in the direction in which the angle of incidence on the image surface is reduced by the 5B lens group G5B having a positive refractive power, and the light beam in the entire fifth lens group G5 It is possible to weaken the flip-up effect and reduce the angle of incidence of light rays in the peripheral field angle on the image sensor, and the advantage is that light rays in the peripheral field angle are less likely to be blocked by the light receiving part of the image sensor even with a large-diameter lens with a large light flux. There is.

In order to realize a high-performance large-diameter anti-vibration zoom lens with the above structure, it is desirable to satisfy the following conditional expressions (1) and (2).
(1) 0.9<EXP/SI<1.8
(2) 0.6<f4/|f5A|<1.3
However,
EXP: Wide-angle end, length from the exit pupil to the image plane when focused on infinity (the direction from the object to the image plane is positive)
SI: Wide-angle end, length from diaphragm to image plane when focused on infinity f4: focal length of fourth lens group G4 f5A: focal length of fifth A lens group G5A

Conditional expression (1) is a preferable range for suppressing the light incident angle of the peripheral field angle to the image sensor with respect to the ratio of the length from the exit pupil to the image plane at the wide-angle end and the length from the diaphragm to the image plane. Is defined. By satisfying the conditional expression (1), it is possible to appropriately set the incident angle of the light ray on the image pickup element so that the light ray is not blocked by the light receiving portion of the image pickup element in a small optical system.

When the lower limit of conditional expression (1) is exceeded and the exit pupil approaches the image plane with respect to the diaphragm, the action of jumping up the rays of the peripheral field angle that have passed through the diaphragm is strengthened in the entire group on the image plane side of the diaphragm, and the peripheral image is increased. Since the angle of incidence of angular rays on the image surface becomes tight, the rays are likely to be eclipsed by the light-receiving portion of the image sensor, especially in the case of a large-diameter lens with a large luminous flux.

On the other hand, if the upper limit of conditional expression (1) is exceeded and the exit pupil is farther from the image plane with respect to the diaphragm, the positive refracting power of the optical system on the image plane side of the diaphragm will be strengthened, and the telecentricity will be enhanced. The angle of incidence of becomes weak. Therefore, the light beam having the peripheral field angle passing through the fifth lens group G5 passes through a high position, the lens diameter is enlarged, and the entire lens system is large and heavy. On the other hand, in order to reduce the lens diameter of the fifth lens group G5, it suffices to move the fifth lens group G5 away from the image plane. However, if the above-described method is performed while reducing the overall length of the optical system, the aperture and the fifth lens can be reduced. The interval between the portions in which the third lens group G3 and the fourth lens group G4 are arranged between the group G5 becomes narrow. As a result, the number of lenses that can be used in the third lens group G3 decreases, and it becomes impossible to perform sufficient axial chromatic aberration correction. In addition, the space in which the fourth lens group G4 moves in focus becomes narrow, and it is difficult to secure a sufficient shortest shooting distance. become.

Further, regarding the conditional expression (1) described above, it is desirable to limit the lower limit value to 0.95 and the upper limit value to 1.5 because the above-mentioned effect can be more surely achieved.

Conditional expression (2) defines a preferable range of the focal length ratio of the fourth lens group G4 which is responsible for focus and the fifth A lens group G5A which is responsible for image stabilization. By satisfying the conditional expression (2), it is possible to appropriately set the incident angle of the light ray on the image pickup element so that the light ray is not blocked by the light receiving portion of the image pickup element in a small optical system.

If the lower limit of conditional expression (2) is exceeded and the positive refracting power of the fourth lens group G4 is increased, the action of refracting the light beam of the peripheral field angle in the direction in which the angle of incidence on the image surface is reduced is increased. If the negative refracting power of the 5A lens group G5A is weakened, the effect of flipping up the light rays of the peripheral field angle is weakened. Therefore, the positive refracting power becomes strong as a composite system of the fourth lens group G4 and the fifth A lens group G5A, and the telecentricity is enhanced, so that the light beam of the peripheral field angle passing through the fourth lens group G4 and the fifth A lens group G5A is As it passes through a high position, the diameters of the fourth lens group G4 and the fifth A lens group G5A are enlarged, which makes it difficult to reduce the weight.

On the other hand, when the upper limit of the conditional expression (2) is exceeded and the positive refractive power of the fourth lens group G4 is weakened, the action of refracting the light beam having the peripheral field angle in the direction in which the incident angle to the image plane becomes smaller, As a result, the negative refracting power of the 5A-th lens group G5A is strengthened, and the effect of flipping up the light rays of the peripheral field angle is enhanced. Therefore, as a composite system of the fourth lens group G4 and the fifth A lens group G5A, the effect of bounce up of light rays at the peripheral field angle is strengthened and the incident angle to the image plane becomes too tight, so that it is a large aperture lens with a particularly large light flux. A light beam is likely to be eclipsed by the light receiving portion of the image sensor.

Further, regarding the conditional expression (2) described above, it is desirable to limit the lower limit value to 0.7 and the upper limit value to 1.2 because the above-mentioned effect can be more surely achieved.

Furthermore, in the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the fifth-A lens group G5A, which is responsible for anti-vibration, be composed of two or less lenses. This makes it possible to reduce the size of the entire lens system by reducing the weight of the image stabilizing group and downsizing the unit for moving the image stabilizing group.

In the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the following conditional expressions (3), (4), and (5) are satisfied.
(3) 0.3<|(1-β5A)βr|<0.9
(4) 0.3<VI/SI<0.8
(5) 1.8<Z1wt/Z5Awt<3.0
However,
β5A: Wide-angle end of the fifth A lens group G5A that is responsible for image stabilization, imaging magnification when focused at infinity βr: Wide-angle end of the group closer to the image plane than the fifth A lens group G5A, synthetic combination when focused at infinity Image magnification VI: Length at the wide-angle end from the surface closest to the image plane of the fifth A lens group G5A to the image surface Z1wt: Movement of the first lens group G1 with respect to the image plane during zooming from the wide-angle end to the telephoto end Amount Z5Awt: The amount of movement of the fifth-A lens unit G5A with respect to the image plane during zooming from the wide-angle end to the telephoto end.

Conditional expression (3) expresses the absolute value of the image stabilization coefficient, and defines the preferable condition. By satisfying the conditional expression (3), it is possible to secure good vibration damping performance while preventing the vibration damping group from being enlarged.

When the lower limit of conditional expression (3) is exceeded and the absolute value of the image stabilization coefficient decreases, the image stabilization effect per unit movement amount of the image stabilization group decreases. Therefore, in order to obtain the desired image stabilization effect, move the image stabilization group. The amount increases, and the lens diameter of the 5A lens group G5A, which is the image stabilizing group, increases.

On the other hand, when the upper limit of conditional expression (3) is exceeded and the absolute value of the image stabilization coefficient becomes large, the refractive power of the image stabilization group becomes too strong, and decentering coma easily occurs. Particularly in the case of a large-diameter zoom lens, since the axial light flux passing through the image stabilizing group is thick, it is easily affected by decentering coma aberration, and it becomes difficult to secure good image stabilizing performance. In addition, the amount of movement of the image stabilization group in the direction perpendicular to the optical axis when performing image stabilization is reduced, making it difficult to accurately control the amount of movement of the image stabilization group.

Further, regarding the conditional expression (3) described above, it is desirable to limit the lower limit value to 0.5 and the upper limit value to 0.75 because the above-mentioned effect can be more surely achieved.

Conditional expression (4) defines a preferable condition regarding the distance from the image plane of the fifth A lens group G5A which is responsible for image stabilization. By satisfying the conditional expression (4), it is possible to secure good vibration damping performance while preventing the vibration damping group from being enlarged.

When the lower limit of conditional expression (4) is exceeded and the image stabilizing unit moves away from the diaphragm and approaches the image plane, the light beam passing position at the peripheral field angle in the image stabilizing unit becomes high, and the lens diameter of the fifth A lens group G5A increases. ..

On the other hand, when the upper limit of conditional expression (4) is exceeded and the image stabilizing unit is close to the diaphragm, the axial marginal ray in the image stabilizing unit becomes high, and decentering coma easily occurs. In particular, in the case of a large-diameter zoom lens, the axial light flux is thick, so that it is easily affected by decentering coma aberration, and it becomes difficult to secure good vibration isolation performance.

Further, regarding the conditional expression (4) described above, it is desirable to limit the lower limit value to 0.4 and the upper limit value to 0.7 because the above-mentioned effect can be more surely achieved.

Conditional expression (5) defines a preferable condition for the ratio of the amount of movement of the first lens unit G1 and the fifth A lens unit G5A to the image plane during zooming from the wide-angle end to the telephoto end. By satisfying the conditional expression (5), good image forming performance can be realized in the entire zoom range with a small optical system.

In the positive group preceding type zoom lens as in the present application, the change in the group distance between the first group to the second group and the second group to the third group is responsible for the main zooming effect, and the fourth lens group G4 and the fifth lens group G5 are variable. Plays an auxiliary role in the fold. If the lower limit of conditional expression (5) is exceeded and the amount of movement of the first lens group G1 becomes small, the variable magnification load of the group spacing between the first group and the second group will decrease, and the variable magnification burden will change from the second group to the third group. Biasing easily causes coma aberration in the second group and the third group. On the other hand, since the moving amount of the fifth A lens group G5A becomes large, the variable magnification load of the fifth A lens group G5A becomes strong, the axial marginal ray becomes high, and eccentric coma aberration occurs at the time of image stabilization, so that good image stabilization performance is achieved. Is difficult to achieve. Further, since the drawing diameter also increases, it becomes difficult to reduce the outer diameter of the product.

On the other hand, when the upper limit of conditional expression (5) is exceeded and the amount of movement of the first lens group G1 increases, the diameter increases. On the other hand, when the amount of movement of the 5A-th lens group G5A decreases, the role of assisting zooming due to changes in the group spacing of the 1st to 2nd groups and the 2nd to 3rd groups weakens, so the 2nd lens group G2 and the 3rd lens group The load of zooming on G3 increases and it becomes difficult to suppress coma. Further, since the fifth-A lens group G5A is close to the image plane at the telephoto end, the light beam passing position at the peripheral field angle becomes high, and the diameter of the fifth-A lens group G5A is enlarged.

Further, regarding the conditional expression (5) described above, it is desirable to limit the lower limit value to 1.85 and the upper limit value to 2.5 because the above-mentioned effect can be more surely achieved.

Furthermore, in the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the first lens group G1 be composed of two or less lenses. This makes it possible to reduce the number of constituent lenses of the first lens group G1 having a large diameter and reduce the weight of the entire lens system.

In the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the following conditional expression (6) is satisfied.
(6) 7.5<f1/|f2|<15.0
However,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

Conditional expression (6) defines a preferable condition for the ratio of the focal lengths of the first lens group G1 and the second lens group G2. By satisfying conditional expression (6), it is possible to realize a good imaging performance in the entire zoom range while reducing the size and weight of the system.

When the lower limit of conditional expression (6) is exceeded and the refractive power of the first lens group G1 is increased, the amount of aberration generated in the first lens group G1 increases. Therefore, if the number of the first lens group G1 is limited to 2 or less, the astigmatism and the distortion aberration generated in the first lens group G1 cannot be suppressed, and the weight can be reduced by suppressing the number of the first lens group G1 to 2 or less. It will be difficult. Further, when the positive refractive power of the first lens group G1 is increased or the negative refractive power of the second lens group G2 is weakened, the entrance pupil moves to the image plane side, and the lower ray of the peripheral field angle is easily eclipsed. It becomes difficult to secure the amount of peripheral light.

On the other hand, when the upper limit of conditional expression (6) is exceeded and the refractive power of the first lens group G1 weakens with respect to the second lens group G2, the first lens group G2 with respect to the second lens group G2 when zooming from the wide-angle end to the telephoto end is performed. The amount of movement of the lens group G1 increases, which makes it difficult to reduce the size of the optical system. Further, the refracting power of the second lens group G2 is strengthened, and it becomes difficult to suppress astigmatism and coma.

Further, regarding the conditional expression (6) described above, it is desirable to limit the lower limit value to 8.0 and the upper limit value to 12.0 because the above-mentioned effect can be more surely achieved.

Further, in the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the third lens group G3 includes at least one three-lens cemented lens. As a result, it is possible to correct axial chromatic aberration and the like while suppressing the sensitivity to manufacturing errors of the group behind the aperture of the positive group preceding type zoom as in the present application. In particular, the decentering sensitivity of a large-diameter zoom lens can be suppressed by joining three lenses.

In the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the following conditional expression (7) is satisfied.
(7) 1.6<f3/fw<3.2
However,
f3: Focal length of third lens group G3 fw: Wide-angle end, focal length of the entire lens system when focused on infinity.

Conditional expression (7) defines a preferable condition for the ratio of the focal lengths of the third lens group G3 and the entire lens system at the wide-angle end. By satisfying conditional expression (7), it is possible to realize an optical system that is compact and has reduced sensitivity to manufacturing errors.

If the lower limit of conditional expression (7) is exceeded and the refracting power of the third lens group G3 is increased, the burden of aberrations such as spherical aberration and coma will increase, and the sensitivity to manufacturing errors will be significantly deteriorated especially for large-diameter zoom lenses.

On the other hand, when the upper limit of conditional expression (7) is exceeded and the positive refracting power of the third lens group G3 weakens, the focusing action of the light flux of the third lens group G3 weakens, so that the image surface becomes stronger than the third lens group G3. The diameter of the side group increases.

Further, regarding the conditional expression (7) described above, it is desirable to limit the lower limit value to 1.7 and the upper limit value to 2.5 because the above-mentioned effect can be more surely achieved.

Further, in the large-diameter anti-vibration zoom lens according to the present invention, it is desirable that the fourth lens group G4, which is a focus group, be composed of one positive lens and have at least one aspherical surface. This makes it possible to reduce the occurrence of aberrations while reducing the weight of the focus group, and to realize good imaging performance over the entire shooting distance from infinity to the closest distance.

In the large-diameter anti-vibration zoom lens of the present invention, it is desirable that the following conditional expression (8) is satisfied.
(8) 0.8<f4/f3<1.6

Conditional expression (8) defines a preferable condition regarding the ratio of the focal lengths of the third lens group G3 and the fourth lens group G4. By satisfying the conditional expression (8), it is possible to suppress variation in aberration during focusing with a small optical system and realize good imaging performance over the entire shooting distance.

If the lower limit of conditional expression (8) is exceeded and the refracting power of the third lens group G3 weakens, the effect of refracting the upper ray of the peripheral field angle passing through the third lens group G3 weakens, so the periphery of the fourth lens group G4 decreases. The ray height above the angle of view becomes high. On the other hand, since the refracting power of the fourth lens group G4 is increased, the fluctuation of the upper ray flare at the time of focusing increases, and it becomes difficult to maintain good imaging performance over the entire shooting distance.

On the other hand, if the upper limit of conditional expression (8) is exceeded and the refracting power of the fourth lens group G4 is weakened, the focus movement amount increases, and it becomes difficult to downsize the lens system. Further, when the refracting power of the third lens group G3 is increased, the focusing action of the axial light flux incident on the fourth lens group G4 is strengthened, so that the fourth lens when the fourth lens group G4 moves along the optical axis during focusing. The height variation of the axial marginal ray in the group G4 becomes large, and the spherical aberration variation at the time of focusing increases, so that it becomes difficult to maintain good imaging performance over the entire shooting distance.

Further, regarding the conditional expression (8) described above, it is desirable to limit the lower limit value to 1.0 and the upper limit value to 1.5 because the above-mentioned effect can be more surely achieved.

Next, the lens configuration and specific numerical data of each embodiment relating to the large-diameter anti-vibration zoom lens of the present invention will be described. In the following description, the lens configurations will be described in order from the object side to the image side.

In [Surface data], the surface number is the lens surface or aperture stop number counted from the object side, r is the radius of curvature of each surface, d is the distance between the surfaces, and nd is for the d line (wavelength λ=587.56 nm). Refractive index, νd indicates the Abbe number for the d-line. BF represents back focus.

In the surface numbered (aperture stop), the radius of curvature ∞ (infinity) for a plane or aperture stop is entered.

In [Aspherical surface data], each coefficient value giving the aspherical surface shape of the lens surface indicated by * in [Surface data] is shown. The shape of the aspherical surface is y in the direction orthogonal to the optical axis, z in the optical axis direction from the intersection of the aspherical surface and the optical axis, and z, the conic coefficient is K, 4, 6, 8, When the tenth-order aspherical surface coefficients are A4, A6, A8, and A10, the coordinates of the aspherical surface are represented by the following equations.

In [Various data], values such as the focal length are shown.

[Variable interval data] indicates the variable interval and BF (back focus) value in each shooting distance state.

The [lens group data] shows the surface number of the lens group closest to the object side and the combined focal length of the entire group.

In all the values of the following specifications, the focal length f, the radius of curvature r, the lens surface distance d, and other units of length are millimeters (mm) unless otherwise specified. The same optical performance can be obtained in the system even in the case of proportional enlargement and proportional reduction, so the present invention is not limited to this.

In the aberration diagrams corresponding to the respective examples, d, g, and C represent d line, g line, and C line, respectively, and ΔS and ΔM represent sagittal image plane and meridional image plane, respectively.

Further, in the lens configuration diagrams shown in FIGS. 1, 14, 27 and 40, S is an aperture stop, I is an image plane, F is a filter in a camera, and a chain line passing through the center is an optical axis.

FIG. 1 is a lens configuration diagram of a large-diameter anti-vibration zoom lens according to a first embodiment of the present invention.

The first lens group G1 is composed of a cemented lens including a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and has a positive refracting power as a whole. ing.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed to the object side, a cemented lens including a biconcave negative lens L22 and a biconvex positive lens L23, and a negative surface concave to the object side. It is composed of a meniscus lens L24 and has a negative refracting power as a whole. Both surfaces of the negative meniscus lens L21 have a predetermined aspherical shape.

The third lens group G3 includes an aperture stop S, a biconvex positive lens L31, a positive meniscus lens L32 having a concave surface facing the object side, a biconcave negative lens L33, and a biconvex positive lens L34. It has a positive refracting power as a whole. The image-side surface of the positive lens L31 has a predetermined aspherical shape.

The fourth lens group G4 is composed of a biconvex positive lens L41, has a positive refracting power as a whole, and moves toward the object side along the optical axis when focusing from infinity to close distance. To do. The surface of the positive lens L41 on the object side has a predetermined aspherical shape.

The fifth lens group G5 is composed of, in order from the object side, a fifth A lens group G5A having a negative refractive power and a fifth B lens group G5B having a positive refractive power, and has a negative refractive power as a whole. The 5A-th lens group G5A is composed of a cemented lens including a biconvex positive lens L51 and a biconcave negative lens L52, has a negative refracting power as a whole, and is in a direction perpendicular to the optical axis. Anti-vibration is performed by moving it. The fifth-B lens group G5B is a cemented lens including a biconvex positive lens L53, a biconcave negative lens L54, a biconvex positive lens L55, and a negative meniscus lens L56 having a concave surface facing the object side. It has a positive refractive power as a whole.

Further, during zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. However, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 are independently moved to the object side.

Next, the specifications of the large-diameter anti-vibration zoom lens according to Example 1 are shown below.

Numerical Example 1
Unit: mm
[Surface data]
Surface number rd nd vd Effective radius Object surface ∞ (d0)
1 71.6005 1.5000 1.80809 22.76 31.66
2 50.4155 11.5789 1.72916 54.67 30.10
3 292.7739 (d3) 29.06
4* 55.5305 1.0000 1.69350 53.20 15.42
5* 12.9559 8.6633 11.20
6 -34.0493 1.0974 1.58913 61.25 10.80
7 17.4487 6.0004 1.80518 25.46 9.88
8 -71.6329 3.7052 9.39
9 -23.2645 1.0006 1.84666 23.78 8.00
10 -54.5604 (d10) 8.35
11 (Aperture) ∞ 2.0000 6.77
12 37.1499 2.9318 1.74330 49.33 9.75
13* -208.9382 4.7416 9.81
14 -188.7833 3.3269 1.77250 49.62 10.18
15 -27.5356 1.0000 1.80610 33.27 10.29
16 37.0997 6.2207 1.45860 90.19 10.68
17 -22.4562 (d17) 11.26
18* 47.7938 3.4338 1.74330 49.33 11.37
19 -82.5177 (d19) 11.32
20 1347.8701 2.2000 1.80518 25.46 9.90
21 -83.7246 0.8000 1.83481 42.72 9.88
22 39.0609 3.4846 9.86
23 238.7980 3.3198 1.55032 75.50 10.40
24 -39.0995 0.1500 10.60
25 -154.0686 3.3884 1.91082 35.25 10.65
26 36.9328 0.6546 10.95
27 30.5270 7.5025 1.72342 37.99 11.52
28 -20.3426 1.0000 1.88300 40.80 11.59
29 -112.7180 12.9957 11.99
30 ∞ 2.0000 1.51680 64.20 13.29
31 ∞ (BF)

[Aspherical data]
4 faces 5 faces 13 faces 18 faces
K 0.0000 0.0000 0.0000 0.0000
A4 9.25593E-07 -1.05509E-05 1.56497E-05 -4.50424E-06
A6 1.10198E-08 -2.34869E-08 -3.02654E-09 9.76031E-09
A8 -3.48268E-12 -2.35618E-10 8.19302E-11 -7.55329E-11
A10 8.26137E-15 0.00000E+00 -3.50870E-13 2.79728E-13

[Various data]
Zoom ratio 2.76
Wide-angle mid-telephoto focal length 17.55 35.00 48.47
F number 2.92 2.92 2.92
Full angle of view 2ω 81.42 44.59 32.32
Image height Y 13.49 14.20 14.20
Total lens length 126.29 145.53 166.99

[Variable interval data]
[Infinity]
Wide-angle mid-telephoto
d0 ∞ ∞ ∞
d3 1.0000 17.4259 35.6210
d10 16.4956 3.0964 1.0000
d17 5.3804 5.8613 6.6021
d19 6.7217 6.7419 5.5707
BF 1.0000 16.7064 22.4957

[40 times the distance]
Wide-angle mid-telephoto
d0 673.9812 1351.1445 1850.5541
d3 1.0000 17.4259 35.6210
d10 16.4956 3.0964 1.0000
d17 5.1239 5.4788 6.1129
d19 6.9783 7.1244 6.0599
BF 1.0000 16.7064 22.4957

[Lens group data]
Focal length of group start surface
G1 1 134.58
G2 4 -15.85
G3 11 37.20
G4 18 41.18
G5A 20 -47.37
G5B 23 103.16

FIG. 14 is a lens configuration diagram of a large-diameter anti-vibration zoom lens according to a second exemplary embodiment of the present invention.

The first lens group G1 is composed of a cemented lens including a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and has a positive refracting power as a whole. ing.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed to the object side, a cemented lens including a biconcave negative lens L22 and a biconvex positive lens L23, and a negative surface concave to the object side. It is composed of a meniscus lens L24 and has a negative refracting power as a whole. Both surfaces of the negative meniscus lens L21 have a predetermined aspherical shape.

The third lens group G3 includes an aperture stop S, a cemented lens including a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32, and a positive meniscus lens L33 having a concave surface directed toward the object side. The double-concave negative lens L34 and the double-convex positive lens L35 constitute a triplet cemented lens, and have a positive refracting power as a whole. The image-side surface of the positive lens L32 has a predetermined aspherical shape.

The fourth lens group G4 is composed of a biconvex positive lens L41, has a positive refracting power as a whole, and moves toward the object side along the optical axis when focusing from infinity to close distance. To do. The surface of the positive lens L41 on the object side has a predetermined aspherical shape.

The fifth lens group G5 is composed of, in order from the object side, a fifth A lens group G5A having a negative refractive power and a fifth B lens group G5B having a positive refractive power, and has a negative refractive power as a whole. The 5A-th lens group G5A is composed of a cemented lens including a biconvex positive lens L51 and a biconcave negative lens L52, has a negative refracting power as a whole, and is in a direction perpendicular to the optical axis. Anti-vibration is performed by moving it. The fifth-B lens group G5B includes a cemented lens including a biconvex positive lens L53 and a biconcave negative lens L54, a biconvex positive lens L55, and a negative meniscus lens L56 having a concave surface facing the object side. It has a positive refracting power as a whole.

Further, during zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. However, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 are independently moved to the object side.

Next, the specifications of the large-diameter anti-vibration zoom lens according to Example 2 are shown below.
Numerical Example 2
Unit: mm
[Surface data]
Surface number rd nd vd Effective radius Object surface ∞ (d0)
1 71.2736 1.5000 1.80809 22.76 31.36
2 52.7597 11.0215 1.72916 54.67 30.00
3 267.2931 (d3) 28.89
4* 44.3356 1.0000 1.80139 45.45 15.07
5* 13.4467 8.7544 11.34
6 -32.6777 1.0000 1.54814 45.82 10.94
7 19.4790 5.1801 1.84666 23.78 10.04
8 -81.2332 3.7608 9.63
9 -25.3571 1.0000 1.90366 31.31 8.00
10 -72.4372 (d10) 8.26
11 (Aperture) ∞ 2.0000 6.71
12 33.3004 1.0000 1.80420 46.50 9.55
13 16.0886 5.0600 1.73077 40.50 9.61
14* -110.3845 5.7554 9.69
15 -80.2451 3.0878 1.77250 49.62 10.16
16 -25.4884 1.0000 1.80518 25.46 10.35
17 58.6132 5.2834 1.59282 68.62 10.89
18 -24.2061 (d18) 11.22
19* 42.5921 3.2014 1.77250 49.50 10.94
20 -177.5602 (d20) 10.85
21 1517.8695 2.1477 1.80518 25.46 9.90
22 -85.0000 0.8000 1.83481 42.72 9.82
23 32.2537 3.2454 9.67
24 80.5859 2.4909 1.55032 75.50 10.10
25 -196.5603 5.3941 1.83400 37.34 10.27
26 47.5023 0.6546 10.96
27 36.2699 5.7333 1.64769 33.84 11.49
28 -32.1451 1.0000 1.88300 40.80 11.65
29 -69.5416 13.9817 11.93
30 ∞ 2.0000 1.51680 64.20 13.29
31 ∞ (BF)

[Aspherical data]
4 faces 5 faces 14 faces 19 faces
K 0.0000 0.0000 0.0000 0.0000
A4 8.38690E-06 3.56433E-07 1.64108E-05 -4.28814E-06
A6 -3.05196E-08 -1.39249E-08 3.74793E-09 -1.67464E-09
A8 6.07974E-11 -2.97407E-10 0.00000E+00 0.00000E+00
A10 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.76
Wide-angle mid-telephoto focal length 17.56 35.00 48.47
F number 2.92 2.92 2.92
Full angle of view 2ω 81.27 44.32 32.27
Image height Y 13.49 14.20 14.20
Total lens length 125.00 144.72 165.00

[Variable interval data]
[Infinity]
Wide-angle mid-telephoto
d0 ∞ ∞ ∞
d3 1.0000 20.5429 36.6669
d10 16.7019 3.3510 1.0000
d18 5.2075 4.7275 5.7457
d20 4.0382 5.0709 3.9388
BF 1.0000 13.9755 20.5962

[40 times the distance]
d0 673.9402 1342.4952 1844.0798
d3 1.0000 20.5429 36.6669
d10 16.7019 3.3510 1.0000
d18 4.9606 4.3703 5.3036
d20 4.2851 5.4281 4.3809
BF 1.0000 13.9755 20.5962

[Lens group data]
Focal length of group start surface
G1 1 136.52
G2 4 -15.82
G3 11 31.69
G4 19 44.75
G5A 21 -38.94
G5B 24 90.88

FIG. 27 is a lens configuration diagram of a large-diameter anti-vibration zoom lens according to a third embodiment of the present invention.

The first lens group G1 is composed of a cemented lens including a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and has a positive refracting power as a whole. ing.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed to the object side, a cemented lens including a biconcave negative lens L22 and a biconvex positive lens L23, and a negative lens having a concave surface directed to the object side. It is composed of a meniscus lens L24 and has a negative refracting power as a whole. Both surfaces of the negative meniscus lens L21 have a predetermined aspherical shape.

The third lens group G3 is a three-element cement consisting of an aperture stop S, a biconvex positive lens L31, a biconvex positive lens L32, a biconcave negative lens L33, and a biconvex positive lens L34. It has a positive refracting power as a whole. The image-side surface of the positive lens L31 has a predetermined aspherical shape.

The fourth lens group G4 is composed of a biconvex positive lens L41, has a positive refracting power as a whole, and moves toward the object side along the optical axis when focusing from infinity to close distance. To do. The surface of the positive lens L41 on the object side has a predetermined aspherical shape.

The fifth lens group G5 is composed of, in order from the object side, a fifth A lens group G5A having a negative refractive power and a fifth B lens group G5B having a positive refractive power, and has a negative refractive power as a whole. The 5A-th lens group G5A is composed of a cemented lens including a biconvex positive lens L51 and a biconcave negative lens L52, has a negative refracting power as a whole, and is in a direction perpendicular to the optical axis. Anti-vibration is performed by moving it. The fifth-B lens group G5B includes a negative meniscus lens L53 having a convex surface directed toward the object side and a biconvex positive lens L54, and has a positive refracting power as a whole.

Upon zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases, The third lens group G3, the fourth lens group G4, and the fifth lens group G5 are independently movable toward the object side.

Next, the specifications of the large-diameter anti-vibration zoom lens according to Example 3 are shown below.
Numerical Example 3
Unit: mm
[Surface data]
Surface number rd nd vd Effective radius Object surface ∞ (d0)
1 90.1206 1.5000 1.80809 22.76 32.34
2 65.3780 9.5853 1.72916 54.67 31.20
3 438.1744 (d3) 30.38
4* 61.7879 1.0000 1.61881 63.85 17.25
5* 14.1406 9.5925 12.48
6 -41.0348 1.8139 1.64769 33.84 12.08
7 18.8855 6.1095 1.84666 23.78 10.96
8 -72.7032 2.6786 10.57
9 -27.3024 1.0000 1.90366 31.31 9.50
10 -60.9742 (d10) 9.51
11 (Aperture) ∞ 2.0000 6.93
12 30.2519 5.9039 1.58313 59.46 9.71
13* -763.3227 6.1452 9.82
14 166.1256 3.8737 1.77250 49.62 10.42
15 -31.4255 1.0000 1.80610 33.27 10.49
16 36.2704 6.1809 1.45860 90.19 10.71
17 -24.3929 (d17) 11.01
18* 37.4881 3.2452 1.74330 49.33 10.71
19 -605.3606 (d19) 10.59
20 232.9023 2.2000 1.80518 25.46 10.00
21 -80.0000 0.8000 1.83481 42.72 9.92
22 30.3494 3.6174 9.78
23 121.3371 1.0000 1.92119 23.96 10.30
24 36.4420 1.9456 10.47
25 34.8233 4.0037 1.80610 33.27 11.74
26 -208.1651 15.6763 11.87
27 ∞ 2.0000 1.51680 64.20 13.29
28 ∞ (BF)

[Aspherical data]
4 faces 5 faces 13 faces 18 faces
K 0.0000 0.0000 0.0000 0.0000
A4 2.87384E-06 -6.51473E-06 1.81586E-05 -3.88442E-06
A6 -1.52627E-08 -2.15959E-08 1.65849E-08 1.51745E-09
A8 6.18212E-11 -3.03608E-10 -6.42106E-11 -3.79859E-11
A10 -5.09925E-14 0.00000E+00 1.97437E-13 1.33796E-13

[Various data]
Zoom ratio 2.76
Wide-angle mid-telephoto focal length 17.52 35.00 48.48
F number 2.91 2.92 2.92
Full angle of view 2ω 82.01 44.33 32.20
Image height Y 13.49 14.20 14.20
Total lens length 126.92 144.64 165.58

[Variable interval data]
[Infinity]
Wide-angle mid-telephoto
d0 ∞ ∞ ∞
d3 1.0000 22.5031 40.9832
d10 22.2727 4.7508 1.0000
d17 4.6103 4.6688 6.2726
d19 5.1623 5.2264 4.9891
BF 1.0000 14.6153 19.4605

Wide-angle mid-telephoto
d0 671.4567 1342.1314 1843.8528
d3 1.0000 22.5031 40.9832
d10 22.2727 4.7508 1.0000
d17 4.3380 4.2784 5.7805
d19 5.4346 5.6168 5.4811
BF 1.0000 14.6153 19.4605

[Lens group data]
[40 times the distance]
Focal length of group start surface
G1 1 161.59
G2 4 -19.90
G3 11 35.10
G4 18 47.60
G5A 20 -41.21
G5B 23 98.06

FIG. 40 is a lens configuration diagram of a large-diameter anti-vibration zoom lens according to Example 4 of the present invention.

The first lens group G1 is composed of a cemented lens including a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and has a positive refracting power as a whole. ing.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface directed to the object side, a cemented lens including a biconcave negative lens L22 and a biconvex positive lens L23, and a negative surface concave to the object side. It is composed of a meniscus lens L24 and has a negative refracting power as a whole. Both surfaces of the negative meniscus lens L21 have a predetermined aspherical shape.

The third lens group G3 includes an aperture stop S, a biconvex positive lens L31, a positive meniscus lens L32 having a concave surface facing the object side, a biconcave negative lens L33, and a biconvex positive lens L34. It has a positive refracting power as a whole. The image-side surface of the positive lens L31 has a predetermined aspherical shape.

The fourth lens group G4 is composed of a biconvex positive lens L41, has a positive refracting power as a whole, and moves toward the object side along the optical axis when focusing from infinity to close distance. To do. The surface of the positive lens L41 on the object side has a predetermined aspherical shape.

The fifth lens group G5 is composed of, in order from the object side, a fifth A lens group G5A having a negative refractive power and a fifth B lens group G5B having a positive refractive power, and has a negative refractive power as a whole. The 5A-th lens group G5A is composed of a cemented lens including a biconvex positive lens L51 and a biconcave negative lens L52, has a negative refracting power as a whole, and is in a direction perpendicular to the optical axis. Anti-vibration is performed by moving it. The fifth-B lens group G5B includes a positive meniscus lens L53 having a concave surface facing the object side, a cemented lens including a biconvex positive lens L54 and a biconcave negative lens L55, and a biconvex positive lens L56. The cemented lens is composed of a negative meniscus lens L57 having a concave surface facing the object side, and has a positive refracting power as a whole.

Upon zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases, The third lens group G3, the fourth lens group G4, and the fifth lens group G5 are independently movable toward the object side.

Next, the specification values of the large-diameter anti-vibration zoom lens according to Example 4 are shown below.
Numerical Example 4
Unit: mm
[Surface data]
Surface number rd nd vd Effective radius Object surface ∞ (d0)
1 72.1607 1.5000 1.80809 22.76 31.93
2 51.3792 11.6592 1.72916 54.67 30.40
3 322.5686 (d3) 29.36
4* 72.7899 1.0000 1.69350 53.20 15.73
5* 13.6877 8.5839 11.45
6 -37.4558 1.0000 1.65844 50.85 11.03
7 18.7365 6.0000 1.92119 23.96 10.39
8 -82.5670 4.9020 10.00
9 -22.6089 1.0000 1.92119 23.96 8.00
10 -54.4232 (d10) 8.33
11 (Aperture) ∞ 2.0000 6.73
12 39.5719 2.9170 1.77250 49.50 9.79
13* -139.1311 4.9775 9.86
14 -192.8210 2.9246 1.83481 42.72 10.27
15 -33.0352 1.0000 1.80610 33.27 10.38
16 36.6738 6.1646 1.45860 90.19 10.68
17 -21.6903 (d17) 11.25
18* 41.7723 3.2713 1.74330 49.33 11.25
19 -138.6523 (d19) 11.02
20 524.0461 2.2000 1.80518 25.46 9.90
21 -83.6244 0.8000 1.83481 42.72 9.79
22 41.0069 4.0067 9.67
23 -132.0541 2.8755 1.55032 75.50 10.00
24 -33.6 101 0.1500 10.25
25 384.4470 3.3091 1.58913 61.25 10.37
26 -35.6874 4.9335 1.92119 23.96 10.42
27 60.1442 0.6546 11.00
28 41.8009 6.7242 1.78472 25.72 11.42
29 -21.0908 1.0000 1.88300 40.80 11.51
30 -227.5962 12.9998 11.84
31 ∞ 2.0000 1.51680 64.20 13.25
32 ∞ (BF)

[Aspherical data]
4 faces 5 faces 13 faces 18 faces
K 0.0000 0.0000 0.0000 0.0000
A4 8.80642E-06 3.66092E-08 1.62645E-05 -4.04639E-06
A6 -2.22853E-08 -6.95692E-09 1.24419E-08 6.52698E-09
A8 4.89571E-11 -1.42774E-10 -7.49325E-11 -5.59991E-11
A10 -3.65904E-14 0.00000E+00 1.39959E-13 2.45114E-13

[Various data]
Zoom ratio 2.77
Wide-angle mid-telephoto focal length 17.53 35.00 48.48
F number 2.92 2.92 2.92
Full angle of view 2ω 81.80 44.43 32.25
Image height Y 13.49 14.20 14.20
Total lens length 126.78 147.48 167.76

[Variable interval data]
[Infinity]
Wide-angle mid-telephoto
d0 ∞ ∞ ∞
d3 1.0000 19.5881 35.1400
d10 15.3121 3.2345 1.0000
d17 5.1876 4.8229 6.4095
d19 3.7219 4.4257 3.3491
BF 1.0000 14.8593 21.3040
[40 times the distance]
Wide-angle mid-telephoto
d0 673.0908 1345.4158 1849.1587
d3 1.0000 19.5881 35.1400
d10 15.3121 3.2345 1.0000
d17 4.9295 4.4397 5.9287
d19 3.9800 4.8089 3.8299
BF 1.0000 14.8593 21.3040

[Lens group data]
Focal length of group start surface
G1 1 131.85
G2 4 -14.96
G3 11 33.37
G4 18 43.52
G5A 20 -52.28
G5B 23 133.34

[Value corresponding to conditional expression]
Conditional expression/Example 1 2 3 4
(1) EXP/SI 1.04 1.11 1.13 1.00
(2) f4/|f5A| 0.87 1.15 1.15 0.83
(3)|(1-β5A)βr| 0.57 0.69 0.59 0.57
(4) VI/SI 0.48 0.48 0.42 0.53
(5) Z1wt/Z5Awt 1.89 2.04 2.09 2.02
(6) f1/|f2| 8.49 8.63 8.12 8.81
(7) f3/fw 2.12 1.80 2.00 1.90
(8) f4/f3 1.11 1.41 1.36 1.30

G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5A 5A lens group G5B 5B lens group S Aperture stop F In-camera filter I Image plane

Claims (5)

From the object side, in order from the object side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, the aperture stop S, and the third lens moving integrally with the aperture stop with a positive refractive power. It is composed of a group G3, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power,
At the time of zooming from the wide-angle end to the telephoto end, each of the lens groups independently moves to the object side,
The distance between the first lens group G1 and the second lens group G2 increases,
The distance between the second lens group G2 and the third lens group G3 decreases,
The intervals between the third lens group G3, the fourth lens group G4, and the fifth lens group G5 change,
When focusing from infinity to a short distance, the fourth lens group G4 moves toward the object side along the optical axis,
The fifth lens group G5 is composed of, in order from the object side, a fifth A lens group G5A having a negative refractive power and a fifth B lens group G5B having a positive refractive power, and the fifth A lens group G5A is movable in the direction perpendicular to the optical axis. A zoom lens with large-diameter anti-vibration, which is characterized by satisfying the following conditional expressions (1) and (2).
(1) 0.9<EXP/SI<1.8
(2) 0.6<f4/|f5A|<1.3
However,
EXP: Wide-angle end, length from the exit pupil to the image plane when focused on infinity (the direction from the object to the image plane is positive)
SI: Wide-angle end, length from diaphragm to image plane when focused on infinity f4: focal length of fourth lens group G4 f5A: focal length of fifth A lens group G5A
The large-diameter anti-vibration zoom lens according to claim 1, wherein the fifth-A lens group G5A is composed of two or less lenses and satisfies the following conditional expressions (3), (4), and (5).
(3) 0.3<|(1-β5A)βr|<0.9
(4) 0.3<VI/SI<0.8
(5) 1.8<Z1wt/Z5Awt<3.0
However,
β5A: Wide-angle end of the fifth A lens group G5A that plays a role of image stabilization, imaging magnification when focused at infinity βr: Wide-angle end of the group closer to the image plane than the fifth A lens group G5A, synthetic combination when focused at infinity Image magnification VI: Length at the wide-angle end from the surface closest to the image plane of the fifth A lens group G5A to the image surface Z1wt: Movement of the first lens group G1 with respect to the image plane during zooming from the wide-angle end to the telephoto end Amount Z5Awt: The amount of movement of the fifth A lens group G5A with respect to the image plane during zooming from the wide-angle end to the telephoto end. The large-diameter anti-vibration zoom lens according to claim 1, wherein the first lens group G1 is composed of two or less lenses and satisfies the following conditional expression (6).
(6) 7.5<f1/|f2|<15.0
However,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2 The large-diameter anti-vibration zoom lens according to any one of claims 1 to 3, wherein the third lens group G3 includes at least one triplet and satisfies the following conditional expression (7).
(7) 1.6<f3/fw<3.2
However,
f3: Focal length of third lens group G3 fw: Wide-angle end, focal length of the entire lens system when focused on infinity. The fourth lens group G4 is composed of one lens, has at least one aspherical surface, and satisfies the following conditional expression (8). Zoom lens with aperture vibration proof.
(8) 0.8<f4/f3<1.6

Images