JP7325813B2 - Large-aperture zoom lens and imaging device provided with the same - Google Patents

Description

The present invention relates to a large-aperture zoom lens and an imaging apparatus having the same. More particularly, the present invention relates to a large-aperture zoom lens that includes a standard zoom range, a small open F-number, a compact overall length, and is capable of high-speed autofocus control, and an imaging apparatus having the same.

Conventionally, large-aperture zoom lenses with small open F-numbers have excellent correction of various aberrations over the entire zoom range, miniaturization of the entire optical system, and high-speed autofocus control in order to obtain high imaging performance. In order to make this possible, it is desired that the focus lens group be lightened.

For example, in Patent Document 1, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a positive is disclosed as a zoom lens comprising a fourth lens group having a refractive power of , and having a relatively long back focus.

Further, in Patent Document 2, a first lens group with a positive refractive power, a second lens group with a negative refractive power, a third lens group with a positive refractive power, a negative a fourth lens group with a refractive power of , a fifth lens group with a positive refractive power, or a first lens group with a positive refractive power, a second lens group with a negative refractive power, and a third lens group with a positive refractive power , a zoom lens comprising a fourth lens group having a positive refractive power and having a relatively long back focus.

JP 2011-128361 A JP 2012-123156 A

However, the zoom lenses disclosed in the above patent documents have the following problems.

In the conventional zoom lens disclosed in Patent Document 1, the focus lens group is composed of a large number of lenses and is heavy. Therefore, weight reduction of the focus lens group is insufficient to enable high-speed autofocus control.

In addition, when trying to apply the zoom lens disclosed in Patent Document 1 to a camera equipped with a so-called full-size image sensor with an image height equivalent to 21.63 mm, the entire optical system becomes large, The back focus becomes longer and the overall length becomes longer. Therefore, it is particularly unsuitable for application to a mirrorless camera that does not have a mirror for reflecting an image to an optical viewfinder and has a compact and lightweight camera system as a whole.

In the conventional zoom lens disclosed in Patent Document 2, the weight reduction of the focus lens group is insufficient, as in the zoom lens disclosed in Patent Document 1.

Also, although it can be applied to a single-lens reflex camera equipped with a full-size image sensor, it is not suitable for a mirrorless camera because of its relatively long back focus and long overall length.

The present invention has been made in view of the above-mentioned problems of the conventional example, and is a large-aperture zoom lens that includes a standard zoom range, a small maximum F-number, a compact overall length, and is capable of high-speed autofocus control. and an image pickup apparatus having the same.

In order to solve the above-described problems, the large-aperture zoom lens of the first invention comprises, in order from the object side, a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power. The fourth lens group consists of a lens group, a fourth lens group with positive refractive power, and a rear lens group. It has a focusing lens LF consisting of a negative meniscus lens with a convex surface, and when zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, and the second lens group increases. The distance between the lens group and the third lens group decreases, the distance between the third lens group and the fourth lens group decreases, the distance between the fourth lens group and the rear lens group increases, and the distance between the fourth lens group and the rear lens group increases . The four lens groups consist of, in order from the object side, a lens group G41 having at least one positive lens and having positive refractive power as a whole, a positive lens G42 having an aspherical surface, and the focusing lens LF. It is characterized by satisfying the following formula.
(1) -2.0<fF/f4<-0.5
(7) 0.3<f41/f42<0.6
fF: focal length of the focusing lens LF f4: focal length of the fourth lens group
f41: focal length of the lens group G41
f42: focal length of the positive lens G42

In the large-aperture lens of the second aspect of the invention, when the rear lens group consists of two lens groups, the distance between the two lens groups increases during zooming from the wide-angle end to the telephoto end. It is characterized by

The large-aperture lens of the third invention is characterized in that the lens closest to the image plane in the rear lens group is fixed with respect to the image plane during zooming from the wide-angle end to the telephoto end. and

In the large-aperture lens of the fourth aspect of the invention, when zooming from the wide-angle end to the telephoto end, the third lens group and the fourth lens group move toward the object side, and satisfy the following conditional expression: characterized by
(2) 0.7<f3/f4<3.0
f3: focal length of the third lens group f4: focal length of the fourth lens group

A large-aperture lens according to a fifth aspect of the invention is characterized in that the first lens group moves toward the object side during zooming from the wide-angle end to the telephoto end and satisfies the following conditional expression.
(3) -10.0<f1/f2<-3.0
f1: focal length of the first lens group f2: focal length of the second lens group

In the large aperture lens of the sixth aspect of the invention, the first lens group comprises, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a positive lens L12 having a convex surface facing the object side, and a It consists of a positive lens L13 with a convex surface, and is characterized by satisfying the following conditional expression.
(4) νd1n<24.0
(5) 65.0<νd1p
(6) 3.0<νd1p/νd1n
νd1n: Abbe number of the negative meniscus lens L11 νd1p: Abbe number of the positive lens having the lowest dispersion among the positive lens L12 and the positive lens L13

A large aperture lens according to a seventh aspect of the invention is characterized by satisfying the following conditional expression when the rear lens group has a positive refractive power.
(8) 0.0<1/fRW<0.3
fRW: focal length of the rear lens group at the wide-angle end

Further, the large aperture lens of the eighth invention is characterized by satisfying the following conditional expression when the rear lens group has a negative refractive power.
(9) -0.3<1/fRW<0.0
fRW: focal length of the rear lens group at the wide-angle end

In the large-aperture lens of the ninth invention, in the case where the rear lens group consists of one lens group, the rear lens group has a positive lens with a convex surface facing at least the object side closest to the object side. has a lens unit RF1 having positive refractive power as a whole, a lens unit RR1 having at least one negative lens closest to the image side and having negative refractive power as a whole, and satisfies the following conditional expression: It is characterized by
(10) -3.0<fRF1/fRR1<0
fRF1: focal length of the lens unit RF1 fRR1: focal length of the lens unit RR1

In the large aperture lens of the tenth invention, in the case where the rear lens group consists of two or more lens groups, the rear lens group is a positive lens having a convex surface facing the most object side and at least the object side. and a lens group RF2 having positive refractive power as a whole, and a lens group RR2 having at least one negative lens closest to the image side and having negative refractive power as a whole. The distance between the lens group RF2 and the lens group RR2 increases during zooming to the end, and the following conditional expression is satisfied.
(11) -3.0<fRF2/fRR2<0
(12) 0.5<RWD/RTD<1.0
fRF2: focal length of the lens group RF2 fRR2: focal length of the lens group RR2 RWD: composite thickness on the optical axis of the rear lens group at the wide-angle end RTD: on the optical axis of the rear lens group at the telephoto end Synthetic thickness

According to the present invention, it is possible to obtain a large-aperture zoom lens that includes a standard range in the variable power range, a small open F-number, a compact overall length, and is capable of high-speed autofocus control, and an image pickup apparatus having the same.

1 is a lens configuration diagram according to Example 1 of a large aperture zoom lens of the present invention; FIG. 4 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 1 at the wide-angle end and in focus at infinity; FIG. 4 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 1 at an intermediate focal length and infinity. FIG. 4 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 1 at the telephoto end and in focus at infinity; FIG. 4 is a lateral aberration diagram of the large-aperture zoom lens of Example 1 at the wide-angle end and in focus at infinity; FIG. 4 is a lateral aberration diagram of the large-aperture zoom lens of Example 1 at an intermediate focal length and infinity. FIG. 4 is a lateral aberration diagram of the large-aperture zoom lens of Example 1 at the telephoto end and in focus at infinity. FIG. FIG. 5 is a lens configuration diagram according to Example 2 of the large-aperture zoom lens of the present invention; FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 2 at the wide-angle end and in focus at infinity; FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 2 at an intermediate focal length and infinity. FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 2 at the telephoto end and in focus at infinity; FIG. 10 is a lateral aberration diagram of the large-aperture zoom lens of Example 2 at the wide-angle end and in focus at infinity; FIG. 10 is a lateral aberration diagram of the large-aperture zoom lens of Example 2 at an intermediate focal length and infinity. FIG. 10 is a lateral aberration diagram of the large-aperture zoom lens of Example 2 at the telephoto end and in focus at infinity; FIG. 10 is a lens configuration diagram according to Example 3 of the large-aperture zoom lens of the present invention; FIG. 11 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 3 at the wide-angle end and in focus at infinity; FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 3 at an intermediate focal length and infinity. FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 3 at the telephoto end and in focus at infinity; FIG. 10 is a lateral aberration diagram of the large-aperture zoom lens of Example 3 at the wide-angle end and in focus at infinity; FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 3 at an intermediate focal length and infinity. FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 3 at the telephoto end and in focus at infinity; FIG. 11 is a lens configuration diagram according to Example 4 of the large-aperture zoom lens of the present invention; FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 4 at the wide-angle end and in focus at infinity; FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 4 at an intermediate focal length and infinity. FIG. 10 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 4 at the telephoto end and in focus at infinity; FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 4 at the wide-angle end and in focus at infinity; FIG. 10 is a lateral aberration diagram of the large-aperture zoom lens of Example 4 at an intermediate focal length and infinity. FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 4 at the telephoto end and in focus at infinity; FIG. 10 is a lens configuration diagram according to Example 5 of the large-aperture zoom lens of the present invention; FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 5 at the wide-angle end and in focus at infinity; FIG. 11 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 5 at an intermediate focal length and infinity. FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 5 at the telephoto end and in focus at infinity; FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 5 at the wide-angle end and in focus at infinity; FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 5 at an intermediate focal length and infinity. FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 5 at the telephoto end and in focus at infinity; FIG. 11 is a lens configuration diagram according to Example 6 of the large-aperture zoom lens of the present invention; FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 6 at the wide-angle end and in focus at infinity; FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 6 at an intermediate focal length and infinity. FIG. 12 is a longitudinal aberration diagram of the large-aperture zoom lens of Example 6 at the telephoto end and in focus at infinity; FIG. 12 is a lateral aberration diagram of the large-aperture zoom lens of Example 6 at the wide-angle end and in focus at infinity; FIG. 11 is a lateral aberration diagram of the large-aperture zoom lens of Example 6 at an intermediate focal length and infinity. FIG. 12 is a lateral aberration diagram of the large-aperture zoom lens of Example 6 at the telephoto end and in focus at infinity;

Embodiments of the large-aperture zoom lens according to the present invention will be described in detail below with reference to the drawings. In the present invention, a lens unit indicates a single lens or cemented lens that constitutes one optical element as a whole.

1, 8, 15, 22, 29 and 36 are lens configuration diagrams of the large aperture zoom lens of this embodiment. As shown in each lens configuration diagram, the large-aperture zoom lens of this embodiment comprises, in order from the object side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, and a lens group G2 with positive refractive power. It is composed of a third lens group G3, a fourth lens group G4 having a positive refractive power, and a rear lens group GR. The rear lens group GR is composed of one or more lens groups, a positive lens unit having a convex surface facing the object side is arranged closest to the object side, and a negative lens unit is arranged as the lens closest to the image side.

In the large-aperture zoom lens of this embodiment, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves with respect to the image plane, and the third lens group Group G3 moves to the object side. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the rear lens group GR increases.

When the rear lens group GR consists of one lens group, the rear lens group GR is fixed with respect to the image plane. The front lens group of the side lens group GR moves toward the object side, the rear lens group is fixed with respect to the image plane, and the distance between the front lens group and the rear lens group increases.

The fourth lens group G4 has a focusing lens LF composed of a negative meniscus lens with a convex surface facing the object side, which moves toward the image plane side when focusing from an infinity object to a short distance object.

In the large-aperture zoom lens of this embodiment, the distance between the first lens group G1 having positive refractive power and the second lens group G2 having negative refractive power is increased during zooming from the wide-angle end to the telephoto end. By doing so, the main zooming effect is obtained. Here, in order to reduce the amount of movement of the first lens group G1 during zooming, it is preferable to set the refractive power arrangement to a reverse telephoto type at the wide-angle end and a telephoto type at the telephoto end. With such a configuration, it is possible to reduce the amount of movement of the first lens group G1 while shortening the total length of the optical system at the wide-angle end.

Therefore, at the wide-angle end, the first lens group G1 having a positive refractive power and the second lens group G2 having a negative refractive power are arranged close to each other so that their combined refractive power becomes negative. A third lens group G3 having a positive refractive power as a whole is arranged at a position away from the composite system of the first lens group G1 and the second lens group G2 toward the image side, and a positive refractive power is arranged at a position further away toward the image side. A fourth lens group G4 is arranged, and the rear lens group GR is arranged behind it.

On the other hand, at the telephoto end, the second lens group G2 with negative refracting power, the third lens group G3 with positive refracting power, and the fourth lens group G4 with positive refracting power are all brought closer to each other and positioned behind the first lens group G1. The composite refracting power on the side is arranged to be a negative refracting power, and the relationship with the first lens group G1 having a positive refracting power constitutes a telephoto type refracting power arrangement as a whole. Allows for shortening.

In the large-aperture zoom lens of this embodiment, the fourth lens group G4 is composed of a negative meniscus lens with a convex surface facing the object side that moves toward the image plane side when focusing from an infinity object to a close object. It has a focal lens LF. Moreover, the following conditional expression (1) is satisfied.
(1) -2.0<fF/f4<-0.5
fF: focal length of the focusing lens LF f4: focal length of the fourth lens group

In order to move a lightweight lens and enable high-speed autofocus control, it is preferable to reduce the size of the focusing lens LF. In order to miniaturize the focusing lens LF, it is important to make its effective diameter as small as possible. However, if an attempt is made to place the focusing lens LF in the final lens group closest to the image plane in order to reduce the effective diameter of the focusing lens LF, then the electrical equipment for communication with the camera body, etc., placed around the mount would be required. Arrangement of the board becomes difficult, and if priority is given to the arrangement of the electrical board, the effective diameter of the focusing lens LF is excessively restricted, which is not preferable.

In this embodiment, a focusing lens LF is arranged in the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5 is increased during zooming from the wide-angle end to the telephoto end. did. This makes it possible to secure a sufficient moving space on the image plane side of the focusing lens LF whose movement amount is large at the telephoto end when focusing from an infinite object to a close object. Furthermore, in this embodiment, the lens closest to the image plane side in the fourth lens group G4 is the focusing lens LF, so that it is possible to more easily secure a moving space for the focusing lens LF on the image plane side. . Further, in this embodiment, the focusing lens LF is a negative meniscus lens with a convex surface facing the object side, so that aberration fluctuations during focusing can be suppressed.

Conditional expression (1) defines the ratio between the focal length of the fourth lens group G4 in which the focusing lens LF is arranged and the focal length of the focusing lens LF.

If the upper limit of conditional expression (1) is exceeded and the negative refractive power of the focusing lens LF becomes large, the decentration sensitivity of the focusing lens LF increases, and there is a risk that the optical performance will deteriorate depending on the in-focus position. occur.

When the lower limit of conditional expression (1) is exceeded and the negative refractive power of the focusing lens LF becomes small, the amount of movement of the focusing lens LF increases when focusing on a short-distance object, resulting in high-speed autofocus control. becomes difficult to realize.

By limiting the lower limit to -1.4 and the upper limit to -0.8 for conditional expression (1), the above effect can be more reliably obtained.

In the large-aperture zoom lens of this embodiment, the lens closest to the image plane in the rear lens group GR is fixed with respect to the image plane during zooming from the wide-angle end to the telephoto end. This eliminates the need to add a moving mechanism to the lens closest to the image plane, making it easier to increase the outer diameter of the lens closest to the image plane relative to the camera body mount specifications. It is possible to sufficiently suppress the emergence angle of the light flux that forms an image on the peripheral portion of the imaging device.

In the large-aperture zoom lens of this embodiment, the third lens group G3 and the fourth lens group G4 move toward the object side during zooming from the wide-angle end to the telephoto end. Moreover, the following conditional expression (2) is satisfied.
(2) 0.7<f3/f4<3.0
f3: focal length of the third lens group f4: focal length of the fourth lens group

By appropriately moving the third lens group G3 and the fourth lens group G4 toward the object side during zooming from the wide-angle end to the telephoto end, the distance between the third lens group G3 and the fourth lens group G4 can be appropriately adjusted. It is possible to suppress the curvature of field that fluctuates during zooming.

When the lower limit of conditional expression (2) is exceeded and the refractive power of the third lens group G3 increases, the lens spacing between the third lens group G3 and the fourth lens group G4 is changed during zooming to suppress curvature of field. However, due to the influence of the spherical aberration generated in the third lens group G3, the fluctuation of spherical aberration increases in the intermediate zoom range.

If the upper limit of conditional expression (2) is exceeded and the refractive power of the third lens group G3 becomes small, the outer diameter of the fourth lens group G4 becomes large and the refractive power of the fourth lens group G4 becomes too large. , the sensitivity to spherical aberration in the fourth lens group G4 increases. Furthermore, the sensitivity to eccentricity increases, making it difficult to suppress manufacturing variations, which may adversely affect productivity.

By limiting the lower limit to 1.1 and the upper limit to 2.0 for conditional expression (2) described above, the above effects can be more reliably achieved.

In the large-aperture zoom lens of this embodiment, the first lens group moves toward the object side during zooming from the wide-angle end to the telephoto end. Moreover, the following conditional expression (3) is satisfied.
(3) -10.0<f1/f2<-3.0
f1: focal length of the first lens group f2: focal length of the second lens group

When the lower limit of conditional expression (3) is exceeded and the refractive power of the first lens group G1 increases, it becomes difficult to correct spherical aberration and chromatic aberration of magnification on the telephoto end side, and sufficient optical performance cannot be obtained. Further, when the refractive power of the second lens group G2 becomes small, the overall length of the lens becomes large at the wide-angle end.

If the upper limit of conditional expression (3) is exceeded and the refractive power of the first lens group G1 becomes small, the amount of movement of the first lens group G1 during zooming becomes too large. Further, when the refractive power of the second lens group G2 increases, it becomes difficult to correct aberrations on the wide-angle end side, and sufficient optical performance cannot be obtained in the peripheral portion.

By restricting the lower limit to −6.4 and the upper limit to −4.8 for conditional expression (3), the above effect can be more reliably obtained.

In the large aperture zoom lens of this embodiment, the first lens group G1 comprises, in order from the object side, a negative meniscus lens L11 with a convex surface facing the object side, a positive lens L12 with a convex surface facing the object side, and a convex surface facing the object side. It consists of a positive lens L13 directed towards. Moreover, the following conditional expressions (4) to (6) are satisfied.
(4) νd1n<24.0
(5) 65.0<νd1p
(6) 3.0<νd1p/νd1n
νd1n: Abbe number of the negative meniscus lens L11 νd1p: Abbe number of the positive lens having the lowest dispersion among the positive lens L12 and the positive lens L13

In the first lens group G1 having a positive refractive power, the negative lens and the positive lens at the wide-angle end where the angle of view is increased by decreasing the Abbe number of the negative lens and increasing the Abbe number of the positive lens. can be reduced, and the thickness of the entire first lens group G1 can be reduced. Furthermore, by selecting a glass type with low dispersion and high anomalous dispersion for the positive lens of the first lens group G1, longitudinal chromatic aberration and lateral chromatic aberration at the telephoto end can be effectively corrected.

If the upper limit of conditional expression (4) is exceeded and the Abbe number of the negative meniscus lens L11 becomes large, it becomes impossible to select a lightweight glass material with a high refractive index.

If the lower limit of conditional expression (5) is exceeded and the Abbe number of the positive lens, which has the lowest dispersion among the positive lenses L12 and L13, becomes small, the positive lens must be made of a high-dispersion glass material. It becomes difficult to correct chromatic aberration and chromatic aberration of magnification, and it becomes impossible to select a lightweight glass material.

When the lower limit of conditional expression (6) is exceeded and the Abbe number of the positive lens, which has the lowest dispersion among the positive lens L12 and the positive lens L13, becomes small, or when the Abbe number of the negative meniscus lens L11 becomes large, the positive lens becomes Dispersion becomes high, or the dispersion of the negative meniscus lens L11 becomes low, the difference in Abbe number between the positive lens and the negative meniscus lens L11 becomes small, and it becomes difficult to sufficiently thin the first lens group G1. As a result, the total length of the lens is increased, the diameter of the filter is increased, and the weight of the lens is increased.

By limiting the lower limit to 16.0 and the upper limit to 21.0 for conditional expression (4) described above, the above effects can be more reliably achieved.

By limiting the lower limit to 70.0 and the upper limit to 96.0 for conditional expression (5) described above, the above effects can be more reliably achieved.

By limiting the lower limit to 3.9 and the upper limit to 5.8 for conditional expression (6) described above, the above effects can be more reliably achieved.

In the large aperture zoom lens of this embodiment, the fourth lens group comprises, in order from the object side, a lens group G41 having at least one positive lens and having positive refractive power as a whole, a positive lens G42 having an aspherical surface, It consists of a focal lens LF. Moreover, the following conditional expression (7) is satisfied.
(7) 0.3<f41/f42<0.6
f41: focal length of the lens group G41 f42: focal length of the positive lens G42

When the refractive power of the lens group G41, which has at least one positive lens and has a positive refractive power as a whole, exceeds the lower limit of conditional expression (7), the lens group G41 and the positive lens G42 having an aspherical surface are combined. The relative shift sensitivity of the lens increases, and the deterioration of optical performance due to manufacturing errors increases, which may adversely affect productivity.

When the upper limit of conditional expression (7) is exceeded and the refractive power of the positive lens G42 increases, the positive lens G42, which is an aspherical lens, becomes more sensitive to surface-to-surface shift eccentricity errors, making it difficult to suppress manufacturing variations. As a result, there is a risk of adversely affecting productivity.

Further, by limiting the lower limit to 0.34 and the upper limit to 0.47 for conditional expression (7) described above, the above effects can be more reliably achieved.

In the large-aperture zoom lens of this embodiment, the following conditional expression (8) is satisfied when the rear lens group GR has a positive refractive power.
(8) 0.0<1/fRW<0.3
fRW: focal length of the rear lens group at the wide-angle end

If the refracting power of the rear lens group GR is positive, the imaging magnification of the rear lens group GR becomes small, which is disadvantageous for miniaturization, but it is placed closer to the object side than the rear lens group GR. Since the power of each lens group can be relaxed, it is advantageous for high performance.

If the upper limit of conditional expression (8) is exceeded and the positive refracting power of the rear lens group GR increases, this is advantageous for high performance, but the amount of movement of each lens group increases during zooming. put away. In particular, if the amount of movement of the first lens group G1 becomes too large, it is disadvantageous for reducing the outer diameter.

By limiting the upper limit of conditional expression (8) to 0.004, the above effect can be more reliably obtained.

In the large-aperture zoom lens of this embodiment, the following conditional expression (9) is satisfied when the rear lens group GR has a negative refractive power.
(9) -0.3<1/fRW<0.0
fRW: focal length of the rear lens group at the wide-angle end

If the refractive power of the rear lens group GR is negative, the imaging magnification of the rear lens group GR increases. Since it can be shortened, it is advantageous for reducing the overall length of the lens.

If the lower limit of conditional expression (9) is exceeded and the negative refracting power of the rear lens group GR becomes large, it is advantageous for downsizing, but it becomes difficult to maintain sufficient optical performance.

By limiting the lower limit of conditional expression (9) to −0.004, the aforementioned effect can be more reliably obtained.

In the large-aperture zoom lens of this embodiment, when the rear lens group GR consists of one lens group, the rear lens group GR has a positive lens with a convex surface facing at least the object side closest to the object side. has a lens unit RF1 having positive refractive power, and a lens unit RR1 having at least one negative lens closest to the image side and having negative refractive power as a whole. Moreover, the following conditional expression (10) is satisfied.
(10) -3.0<fRF1/fRR1<0
fRF1: focal length of the lens unit RF1 fRR1: focal length of the lens unit RR1

In the rear lens group GR, a lens unit RF1 having a positive lens with a convex surface facing at least the object side closest to the object side and having a positive refractive power as a whole is arranged so that the ray diameter of the rear lens group GR can be adjusted to Since it can be lowered, it is possible to suppress the increase in outer diameter around the mount of the camera body. Further, by arranging the lens unit RR1 having at least one negative lens closest to the image side and having negative refractive power as a whole, it is possible to appropriately control the exit angle of the off-axis ray. Improved curvature can be facilitated.

If the lower limit of conditional expression (10) is exceeded and the positive refractive power of the lens unit RF1 becomes small, the light ray height of the lens closest to the image plane in the image-side lens group GR becomes too large. It becomes difficult to place the lens in the Also, since the negative refractive power of the lens unit RR1 becomes too large, the negative refractive power of the rear lens group GR becomes large, which is advantageous for reducing the overall length of the lens, but makes it difficult to correct aberrations. .

If the upper limit of conditional expression (10) is exceeded and the positive refractive power of the lens unit RF1 increases, the positive refractive power of the rear lens group GR increases, making it difficult to reduce the overall length of the lens. Further, when the negative refractive power of the lens unit RR1 becomes small, it becomes difficult to improve curvature of field.

By limiting the lower limit to −1.5 and the upper limit to −0.2 for the above conditional expression (10), the above effect can be ensured.

In the large-diameter zoom lens of this embodiment, when the rear lens group GR is composed of two or more lens groups, the rear lens group GR has a positive lens with a convex surface facing at least the object side closest to the object side. It has a lens group RF2 having positive refractive power as a whole, and a lens group RR2 having at least one negative lens closest to the image side and having negative refractive power as a whole. , the distance between the lens group RF2 and the lens group RR2 increases. Moreover, the following conditional expressions (11) and (12) are satisfied.
(11) -3.0<fRF2/fRR2<0
(12) 0.5<RWD/RTD<1.0
fRF2: focal length of the lens group RF2 fRR2: focal length of the lens group RR2 RWD: composite thickness on the optical axis of the rear lens group at the wide-angle end RTD: on the optical axis of the rear lens group at the telephoto end Synthetic thickness

In the rear lens group GR, a lens group RF2 having a positive lens with a convex surface facing at least the object side closest to the object side and having positive refractive power as a whole is arranged so that the ray diameter of the rear lens group GR can be reduced. Since it can be lowered, it is possible to suppress the increase in outer diameter around the mount of the camera body. Furthermore, by arranging the lens group RR2 having at least one negative lens closest to the image side and having a negative refractive power as a whole, it is possible to appropriately control the exit angle of the off-axis ray. It can facilitate field curvature improvement across the entire field.

Furthermore, by appropriately moving the lens group RF2 and the lens group RR2 so that the distance between the lens group RF2 and the lens group RR2 increases during zooming from the wide-angle end to the telephoto end, the intermediate region and the Spherical aberration and astigmatism can be changed to the underside in the telephoto end region, and changes in curvature of field during zooming can be appropriately corrected.

If the lower limit of conditional expression (11) is exceeded and the positive refractive power of the lens group RF2 becomes small, the light ray height of the lens group closest to the image plane in the image side lens group GR becomes too large. It becomes difficult to dispose lenses in the periphery. Also, since the negative refractive power of the lens group RR2 becomes too large, the negative refractive power of the rear lens group GR becomes large, which is advantageous for reducing the overall length of the lens, but makes it difficult to correct aberrations. .

If the upper limit of conditional expression (11) is exceeded and the positive refractive power of the lens group RF2 increases, the positive refractive power of the rear lens group GR increases, making it difficult to reduce the overall length of the lens. Further, when the negative refractive power of the lens group RR2 becomes small, it becomes difficult to improve curvature of field.

By limiting the lower limit to −1.5 and the upper limit to −0.2 for conditional expression (11) described above, the aforementioned effects can be more reliably achieved.

Exceeding the lower limit of conditional expression (12) and increasing the amount of movement of the RF2 lens during zooming increases the combined thickness of the rear lens group GR on the optical axis at the telephoto end. Since the distance between the focusing lens LF and the rear lens group GR becomes too short, it becomes difficult to mount a movable mechanism for moving the focusing lens LF.

When the upper limit of conditional expression (12) is exceeded and the combined thickness of the rear lens group on the optical axis at the wide-angle end becomes longer, the distance between the lens group RF2 and the lens group RR2 becomes larger at the wide-angle end and smaller at the telephoto end. As a result, it becomes impossible to obtain the effect of correcting the curvature of field due to the floating.

By limiting the lower limit to 0.85 and the upper limit to 0.95 for conditional expression (12) described above, the above effects can be more reliably achieved.

Next, the lens configuration of the large-aperture zoom lens of this embodiment will be described. In the following description, the lens configuration will be described in order from the object side to the image side.

FIG. 1 is a lens configuration diagram of a large aperture zoom lens of Example 1 according to the present invention.

The large-aperture zoom lens of Example 1 includes a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. and a fifth lens group G5 with negative refractive power. In Example 1, the rear lens group GR is composed of the fifth lens group G5.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a negative meniscus lens L7 having a concave surface facing the object side.

The third lens group G3 is composed of a biconvex lens L8, a cemented lens composed of a biconvex lens L9 and a plano-concave lens L10 having a concave surface facing the object side.

The fourth lens group G4 comprises a biconvex lens L11 as the lens group G41, a positive meniscus lens L12 having a concave surface facing the object as the lens G42, and a negative meniscus lens L13 having a convex surface facing the object as the focusing lens LF. be done.

The fifth lens group G5 includes a cemented lens composed of a biconvex lens L14 and a biconcave lens L15 having positive refractive power as the lens unit RF1, and a plano-concave lens L16 having a negative refractive power and having a concave surface facing the object side as the lens unit RR1. consists of

FIG. 8 is a lens configuration diagram of a large aperture zoom lens of Example 2 according to the present invention.

The large aperture zoom lens of Example 2 includes a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. and a fifth lens group G5 with positive refractive power.
In Example 2, the rear lens group GR is composed of the fifth lens group G5.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a negative meniscus lens L7 having a concave surface facing the object side.

The third lens group G3 is composed of a biconvex lens L8 and a cemented lens composed of a biconvex lens L9 and a negative meniscus lens L10 having a concave surface facing the object side.

The fourth lens group G4 comprises a biconvex lens L11 as the lens group G41, a positive meniscus lens L12 having a concave surface facing the object as the lens G42, and a negative meniscus lens L13 having a convex surface facing the object as the focusing lens LF. be done.

The fifth lens group G5 includes a positive meniscus lens L14 having a convex surface facing the object side as the lens unit RF1, a negative meniscus lens L15 having a convex surface facing the object side, and a negative meniscus lens L16 having a convex surface facing the object side as the lens unit RR1. consists of

FIG. 15 is a lens configuration diagram of a large aperture zoom lens of Example 3 according to the present invention.

The large-aperture zoom lens of Example 3 includes a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. and a fifth lens group G5 with positive refractive power. In Example 3, the rear lens group GR is composed of the fifth lens group G5.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a biconcave lens L7.

The third lens group G3 is composed of a biconvex lens L8 and a cemented lens composed of a biconvex lens L9 and a biconcave lens L10.

The fourth lens group G4 comprises a biconvex lens L11 as a lens group G41, a positive meniscus lens L12 having a concave surface facing the object side as a lens G42, and a negative meniscus lens L13 having a convex surface facing the object side as a focusing lens LF. Configured.

The fifth lens group G5 is composed of a cemented lens composed of a biconvex lens L14 having positive refractive power and a biconcave lens L15 as the lens unit RF1, and a biconcave lens L16 having negative refractive power as the lens unit RR1.

FIG. 22 is a lens configuration diagram of a large aperture zoom lens of Example 4 according to the present invention.

The large-aperture zoom lens of Example 4 includes a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. and a fifth lens group G5 with negative refractive power. In Example 4, the rear lens group GR is composed of the fifth lens group G5.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a negative meniscus lens L7 having a concave surface facing the object side.

The third lens group G3 is composed of a positive meniscus lens L8 having a convex surface facing the object side, a cemented lens composed of a biconvex lens L9 and a biconcave lens L10, and a positive meniscus lens L11 having a convex surface facing the object side.

The fourth lens group G4 includes a cemented lens composed of a negative meniscus lens L12 having a convex surface facing the object side and a positive meniscus lens L13 having a convex surface facing the object side as a lens group G41, a biconvex lens L14, and a biconvex lens L15 as a lens G42. and a negative meniscus lens L16 having a convex surface facing the object side as a focusing lens LF.

The fifth lens group G5 is composed of a positive meniscus lens L17 having a convex surface facing the object side as a lens unit RF1, a negative meniscus lens L18 having a convex surface facing the object side, and a biconcave lens L19 as a lens unit RR1.

FIG. 29 is a lens configuration diagram of a large aperture zoom lens of Example 5 according to the present invention.

The large aperture zoom lens of Example 5 comprises a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. and a fifth lens group G5 with negative refractive power. In Example 5, the rear lens group GR is composed of the fifth lens group G5.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves to the object side, and the fifth lens group G5 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a negative meniscus lens L7 having a concave surface facing the object side.

The third lens group G3 is composed of a biconvex lens L8, a cemented lens composed of a biconvex lens L9 and a plano-concave lens L10 having a concave surface facing the object side.

The fourth lens group G4 comprises a biconvex lens L11 as the lens group G41, a positive meniscus lens L12 having a concave surface facing the object as the lens G42, and a negative meniscus lens L13 having a convex surface facing the object as the focusing lens LF. be done.

The fifth lens group G5 includes a cemented lens composed of a biconvex lens L14 and a biconcave lens L15 having positive refractive power as the lens unit RF1, and a plano-concave lens L16 having a negative refractive power and having a concave surface facing the object side as the lens unit RR1. consists of

FIG. 36 is a lens configuration diagram of a large aperture zoom lens of Example 6 according to the present invention.

The large aperture zoom lens of Example 6 includes a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, and a third lens group G3 with positive refractive power. a fourth lens group G4, a fifth lens group G5 with positive refractive power, and a sixth lens group G6 with negative refractive power.
In Example 6, the rear lens group GR is composed of a fifth lens group G5 and a sixth lens group G6.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object side, the second lens group G2 moves relative to the image plane, the third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side. The fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side, and the sixth lens group G6 is fixed with respect to the image plane. Further, 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, and the distance between the third lens group G3 and the fourth lens group G4 increases. decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases, and the distance between the fifth lens group G5 and the sixth lens group G6 increases.

The aperture diaphragm S is arranged on the object side of the third lens group G3, and the fourth lens group G4 comprises a lens group G41 having positive refractive power, a lens G42 having positive refractive power and an aspherical surface, and a lens group G42 having a positive refractive power and having a negative refractive power. The focusing lens LF is composed of a focusing lens LF having a force, and moves along the optical axis toward the image plane side when focusing from an infinite distance object to a short distance object.

The first lens group G1 is composed of a cemented lens composed of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 having a convex surface facing the object side.

The second lens group G2 is composed of a negative meniscus lens L4 having a convex surface facing the object side, a cemented lens composed of a biconcave lens L5 and a biconvex lens L6, and a negative meniscus lens L7 having a concave surface facing the object side.

The third lens group G3 is composed of a biconvex lens L8, a cemented lens composed of a biconvex lens L9 and a plano-concave lens L10 having a concave surface facing the object side.

The fourth lens group G4 comprises a biconvex lens L11 as the lens group G41, a positive meniscus lens L12 having a concave surface facing the object as the lens G42, and a negative meniscus lens L13 having a convex surface facing the object as the focusing lens LF. be done.

The fifth lens group G5 is composed of a cemented lens consisting of a biconvex lens L14 and a biconcave lens L15 having positive refractive power as the lens group RF2, and the sixth lens group G6 is composed of a lens group RR2 having negative refractive power. It is composed of a plano-concave lens L16 with a concave surface on the side.

Numerical examples of the large-aperture zoom lens of this embodiment will be described below.

In [surface data], the surface number is the number of the lens surface or aperture stop counted from the object side, r is the radius of curvature of each surface, d is the distance between each surface, and nd is the refractive index for the d-line (wavelength 587.56 nm). , vd indicate the Abbe number for the d-line.

An asterisk (*) attached to the surface number indicates that the lens surface shape is aspheric. Also, BF represents back focus.

The (diaphragm) attached to the surface number indicates that the aperture diaphragm is located at that position. ∞ (infinity) is entered for the radius of curvature for a plane or aperture stop.

[Aspheric surface data] shows the value of each coefficient that gives the aspheric shape of the lens surface marked with * in [Surface data]. For the shape of the aspherical surface, y is the displacement from the optical axis in the direction orthogonal to the optical axis, z is the displacement (sag amount) in the direction of the optical axis from the intersection of the aspherical surface and the optical axis, and r is the radius of curvature of the reference spherical surface. , where K is the conic coefficient and An is the n-th order aspheric coefficient, the aspheric surface is represented by the following equation.

[Various data] shows values such as the zoom ratio and the focal length in each focal length state.

[Variable Spacing Data] shows the variable spacing and BF values in each focal length state.

[Lens group data] indicates the number of the surface closest to the object side constituting each lens group and the combined focal length of the entire lens group.

In addition, in the values of all the specifications below, unless otherwise specified, millimeters (mm) are used for the focal length f, radius of curvature r, interval d between surfaces, and other lengths. The system is not limited to this because the same optical performance can be obtained in both proportional enlargement and proportional reduction.

Also, a list of values corresponding to conditional expressions in numerical examples is shown.

In the longitudinal and lateral aberration diagrams corresponding to the numerical examples, d, g and C denote the d-line, g-line and C-line, respectively, and ΔS and ΔM denote the sagittal image plane and the It represents a meridional image plane.

Numerical example 1
Unit: mm
[Surface data]
Face number rd nd vd
1 500.0000 1.6000 1.94595 17.98
2 257.2100 5.7300 1.48749 70.44
3 -276.1000 0.1500
4 52.1100 7.3000 1.48749 70.44
5 120.7700 (d5)
6* 263.0700 1.7500 1.85135 40.10
7* 22.1600 7.5200
8 -46.1200 0.9000 1.59282 68.62
9 22.7500 8.6000 1.77047 29.74
10 -68.4300 2.7967
11 -25.7700 0.9000 1.49700 81.61
12 -103.4100 (d12)
13 (Aperture) ∞ 1.2000
14 42.9100 4.8000 1.59349 67.00
15 -173.8300 1.3500
16 40.3800 7.5200 1.43700 95.10
17 -29.4300 0.8500 1.91082 35.25
18 ∞ (d18)
19 24.7600 9.1400 1.43700 95.10
20 -39.4300 0.3500
21* -1000.0000 3.3600 1.59201 67.02
22* -44.8700 1.9000
23* 154.1200 1.1500 1.69350 53.20
24* 28.2200 (d24)
25 42.8100 5.6000 1.88300 40.80
26 -1455.3000 1.0000 1.53172 48.84
27 30.4600 6.4800
28 -97.2600 1.0000 1.62041 60.34
29∞ (BF)
Image plane ∞

[Aspheric Data]
6 faces 7 faces 21 faces 22 faces
K 0.00000 -1.00000 0.00000 0.00000
A4 1.84200E-05 3.04740E-05 -3.45900E-05 -1.26660E-06
A6 -8.54890E-08 -6.00870E-08 1.27300E-08 3.52850E-08
A8 3.15650E-10 5.07890E-10 1.17030E-09 1.02060E-09
A10 -6.05420E-13 -3.64550E-12 -3.17090E-12 -2.28260E-12
A12 4.69110E-16 2.29920E-14
A14-5.07580E-17

23 planes 24 planes
K 0.00000 0.00000
A4 3.87320E-06 1.41920E-06
A6 -4.56910E-08 -4.88600E-08
A8 2.36610E-10 3.64130E-10

[Various data]
Zoom ratio 2.75
Wide Angle Medium Telephoto Focal Length 24.73 41.57 68.03
F number 2.92 2.92 2.92
Full angle of view 2ω 85.13 54.13 34.30
Image height Y 21.63 21.63 21.63
Overall lens length 135.04 149.77 170.90

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 18.0000 35.3800
d12 17.3000 7.6300 1.5000
d18 8.1700 4.4000 2.4200
d24 7.3000 18.9728 30.8934
BF 17.8252 17.8209 17.7628

[Lens group data]
Group Starting surface Focal length
G1 1 135.08
G2 6 -21.35
G3 14 69.15
G4 19 42.65
G5 25 -998.43

G41 19 36.38
G42 21 79.25
RF1 25 212.55
RR1 28 -156.77

Numerical example 2
Unit: mm
[Surface data]
Face number rd nd vd
1 500.0000 1.8000 1.98613 16.48
2 266.9700 4.8800 1.43700 95.10
3 -464.4200 0.1500
4 58.6000 8.4000 1.59349 67.00
5 206.3900 (d5)
6* 145.3600 1.8000 1.85135 40.10
7* 20.2900 8.4200
8 -38.8300 1.0000 1.55032 75.50
9 24.4400 8.1900 1.77047 29.74
10 -77.8800 3.1200
11 -23.7300 0.9000 1.43700 95.10
12 -104.8900 (d12)
13 (Aperture) ∞ 1.2000
14 44.8300 6.9000 1.43700 95.10
15 -59.6600 0.1500
16 37.5500 8.8000 1.43700 95.10
17 -26.8200 1.0000 1.87071 40.73
18 -566.6100 (d18)
19 26.1500 8.7900 1.43700 95.10
20 -38.9500 0.3500
21* -386.2600 3.0000 1.59201 67.02
22* -46.7800 1.9000
23* 127.3700 1.2000 1.69350 53.20
24* 25.1900 (d24)
25 37.1600 5.0700 1.88300 40.80
26 95.7600 0.6500
27 52.2700 1.2000 1.59270 35.45
28 26.8800 6.0800
29 523.1400 1.2000 1.51823 58.96
30 100.0000 (BF)
Image plane ∞

[Aspheric data]
6 faces 7 faces 21 faces 22 faces
K 0.00000 -1.00000 0.00000 0.00000
A4 3.68420E-06 1.66690E-05 -3.09740E-05 -1.05010E-06
A6 -2.17850E-10 -8.56550E-09 1.49050E-08 2.35950E-08
A8 1.65370E-11 5.64933E-10 1.15870E-09 1.10000E-09
A10 -4.75690E-14 -4.33820E-12 -3.14380E-12 -2.58470E-12
A12 6.26260E-17 1.99830E-14
A14-3.39880E-17

23 planes 24 planes
K 0.00000 0.00000
A4 -2.76330E-06 -6.38440E-06
A6 3.68940E-09 6.78330E-09
A8 6.10140E-11 1.12330E-10

[Various data]
Zoom ratio 2.75
Wide Angle Medium Telephoto Focal Length 24.71 39.74 67.98
F number 2.92 2.92 2.92
Full angle of view 2ω 85.35 56.93 34.34
Image height Y 21.63 21.63 21.63
Overall lens length 138.70 150.12 174.99

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 12.4300 33.4800
d12 16.4000 7.7200 2.1100
d18 8.8200 4.2300 2.3100
d24 7.3000 21.1077 32.4477
BF 18.5268 18.4844 18.4902

[Lens group data]
Group Starting surface Focal length
G1 1 120.99
G2 6 -20.02
G3 14 61.13
G4 19 50.52
G5 25 498.55

G41 19 37.34
G42 21 89.61
RF1 25 66.09
RR1 29 -238.80

Numerical example 3
Unit: mm
[Surface data]
Face number rd nd vd
1 226.2200 1.8000 1.92286 20.88
2 166.3500 7.0000 1.43700 95.10
3 -313.1000 0.1500
4 58.4500 6.6800 1.43700 95.10
5 128.6700 (d5)
6* 500.0000 1.8000 1.85135 40.10
7* 25.3000 7.6600
8 -61.4900 1.0000 1.59282 68.62
9 26.1400 7.3100 1.95375 32.32
10 -149.3300 2.9900
11 -30.4200 0.9000 1.43700 95.10
12 526.9200 (d12)
13 (Aperture) ∞ 1.7400
14 38.4700 7.5300 1.43700 95.10
15 -91.6500 3.9200
16 37.9700 8.3800 1.43700 95.10
17 -29.7100 1.0000 1.88300 40.80
18 633.5700 (d18)
19 25.7600 9.2500 1.43700 95.10
20 -42.7000 0.3500
21* -1000.0000 4.0600 1.59201 67.02
22* -55.6700 1.9000
23* 113.5800 1.2000 1.61881 63.85
24* 24.2200 (d24)
25 48.4300 7.4500 2.00100 29.13
26 -70.2400 1.2000 1.85883 30.00
27 46.4900 3.5700
28 -822.0000 1.2000 1.75211 25.05
29 140.0000 (BF)
Image plane ∞

[Aspheric data]
6 faces 7 faces 21 faces 22 faces
K 0.00000 -1.00000 0.00000 0.00000
A4 3.52320E-05 4.69830E-05 -2.97730E-05 -4.13810E-06
A6 -2.72150E-07 -2.40820E-07 4.08650E-08 6.38560E-08
A8 1.51360E-09 1.01970E-09 5.27200E-10 4.27240E-10
A10 -5.48500E-12 -4.52380E-13 -1.42110E-12 -8.82090E-13
A12 1.24080E-14 -1.04470E-14
A14 -1.58330E-17 3.30960E-17
A16 8.71720E-21 -2.50030E-20

23 planes 24 planes
K 0.00000 0.00000
A4 3.71740E-06 1.23670E-06
A6 -6.92670E-08 -8.17540E-08
A8 2.45690E-10 3.09120E-10

[Various data]
Zoom ratio 2.90
Wide Angle Medium Telephoto Focal Length 28.80 50.10 83.51
F number 2.92 2.92 2.92
Full angle of view 2ω 75.45 45.38 28.22
Image height Y 21.63 21.63 21.63
Total lens length 150.01 168.73 190.44

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 24.2610 43.8000
d12 20.8200 9.6856 2.1400
d18 8.5500 3.5100 0.8100
d24 7.8300 19.9856 32.4396
BF 21.2686 21.2435 21.2102

[Lens group data]
Group Starting surface Focal length
G1 1 148.16
G26-25.50
G3 14 71.24
G4 19 50.34
G5 25 5271.77

G41 19 38.34
G42 21 99.42
RF1 25 173.78
RR1 28 -158.97

Numerical example 4
Unit: mm
[Surface data]
Face number rd nd vd
1 230.0000 1.8000 1.92286 20.88
2 162.9500 5.2100 1.43700 95.10
3 -1585.0000 0.1500
4 65.7200 8.1200 1.49700 81.61
5 371.9600 (d5)
6* 500.0000 1.8000 1.85135 40.10
7* 28.0400 6.9400
8 -69.6300 1.0000 1.59282 68.62
9 19.9400 7.7000 1.69895 30.05
10 -81.6400 3.0600
11 -24.2600 0.9000 1.43700 95.10
12 -296.5700 (d12)
13 (Aperture) ∞ 2.3500
14 94.4500 2.2900 1.88100 40.14
15 1860.0000 0.4500
16 40.6100 8.6100 1.43700 95.10
17 -26.8100 1.0000 1.74951 35.33
18 416.0000 0.5700
19 80.9300 2.2500 1.43700 95.10
20 372.0000 (d20)
21 38.1400 1.0000 1.65160 58.54
22 29.4900 5.8200 1.43700 95.10
23 874.0000 0.1500
24 35.3600 7.5600 1.43700 95.10
25 -51.3300 0.9500
26* 131.2900 2.6000 1.55332 71.68
27* -98.6700 1.9000
28* 146.9100 1.2000 1.69350 53.20
29* 27.9600 (d29)
30 38.2600 4.5900 1.92286 20.88
31 112.1800 0.1500
32 63.1600 1.2000 1.92286 20.88
33 34.4100 5.2800
34 -224.8800 1.2000 1.59551 39.22
35 100.0000 (BF)
Image plane ∞

[Aspheric data]
6 faces 7 faces 26 faces 27 faces
K 0.00000 -1.00000E+00 0.00000 0.00000
A4 3.02180E-05 3.77240E-05 -2.33470E-05 -1.60110E-06
A6 -2.13080E-07 -1.70580E-07 -4.38420E-08 -4.00310E-08
A8 1.19120E-09 4.11330E-10 9.26470E-10 9.96700E-10
A10 -4.16480E-12 4.66200E-12 -2.17890E-12 -2.36520E-12
A12 8.82940E-15 -3.96310E-14
A14 -1.02860E-17 1.27540E-16
A16 5.05860E-21 -1.59180E-19

28 planes 29 planes
K 0.00000 0.00000
A4 3.19050E-05 3.29770E-05
A6 -4.09560E-07 -4.29570E-07
A8 2.81290E-09 2.99450E-09
A10 -1.03010E-11 -1.16520E-11
A12 1.58860E-14 2.19570E-14
A14-8.90390E-18

[Various data]
Zoom ratio 2.89
Wide Angle Medium Telephoto Focal Length 28.69 41.37 82.97
F number 2.92 2.92 2.92
Full angle of view 2ω 77.36 54.82 28.40
Image height Y 21.63 21.63 21.63
Overall lens length 144.99 156.80 184.05

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 15.3000 39.8100
d12 17.5200 10.9800 1.7700
d20 7.1900 4.3600 0.8100
d29 11.3800 18.7697 34.3041
BF 19.6006 19.5865 19.5595

[Lens group data]
Group Starting surface Focal length
G1 1 132.32
G2 6 -22.62
G3 14 87.48
G4 21 43.93
G5 30-440.54

G41 21 35.39
G42 26 102.22
RF1 30 61.10
RR1 34 -116.08

Numerical example 5
Unit: mm
[Surface data]
Face number rd nd vd
1 367.2100 1.6000 1.94595 17.98
2 177.4300 4.9100 1.48749 70.44
3 -247.9000 0.1500
4 46.1700 7.2800 1.48749 70.44
5 200.0000 (d5)
6* 156.0300 1.4500 1.85135 40.10
7* 20.4900 6.1300
8 -42.1600 0.9000 1.59282 68.62
9 19.7600 5.5900 1.77047 29.74
10 -70.8500 2.7100
11 -22.6400 0.9000 1.49700 81.61
12 -83.8900 (d12)
13 (Aperture) ∞ 1.3600
14 45.7100 5.0700 1.69680 55.46
15 -99.4600 0.2400
16 47.0500 6.5500 1.43700 95.10
17 -23.3400 0.8500 1.91082 35.25
18 ∞ (d18)
19 25.2500 8.4000 1.43700 95.10
20 -31.7900 0.3500
21* -1000.0000 2.7700 1.59201 67.02
22* -42.8000 1.9000
23* 200.0000 1.1500 1.69350 53.20
24* 29.4800 (d24)
25 61.0600 6.7600 1.88300 40.80
26 -46.8100 1.0000 1.58144 40.89
27 65.8200 5.2900
28 -38.9500 1.0000 1.69680 55.46
29∞ (BF)
Image plane ∞

[Aspheric Data]
6 faces 7 faces 21 faces 22 faces
K 0.00000 -1.00000E+00 0.00000 0.00000
A4 1.39820E-05 2.98850E-05 -4.27100E-05 -1.07370E-05
A6 -4.75580E-08 -8.26090E-08 -7.65880E-08 -1.30290E-08
A8 1.60560E-10 1.96580E-09 1.84230E-09 1.38960E-09
A10 -1.94840E-13 -2.14680E-11 -4.57400E-12 -2.87450E-12
A12 4.63420E-17 1.28620E-13
A14-2.91770E-16

23 planes 24 planes
K 0.00000 0.00000
A4 2.01970E-05 1.95200E-05
A6 -1.69280E-07 -1.90280E-07
A8 6.10140E-10 8.28740E-10

[Various data]
Zoom ratio 2.35
Wide Angle Medium Telephoto Focal Length 28.81 40.03 67.72
F number 2.92 2.92 2.92
Full angle of view 2ω 76.26 56.14 33.83
Image height Y 21.63 21.63 21.63
Total lens length 124.04 130.61 146.47

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 9.3400 24.7700
d12 12.8800 7.6400 1.5000
d18 8.1400 5.4600 3.1700
d24 7.5600 14.2392 23.1097
BF 19.6513 19.6254 19.6129

[Lens group data]
Group Starting surface Focal length
G1 1 97.94
G2 6 -20.05
G3 14 69.82
G4 19 38.22
G5 25-307.25

G41 19 33.71
G42 21 75.45
RF1 25 81.24
RR1 28 -55.90

Numerical Example 6
Unit: mm
[Surface data]
Face number rd nd vd
1 424.0000 1.6000 1.94595 17.98
2 193.7700 4.7800 1.48749 70.44
3 -239.9400 0.1000
4 46.6600 7.2100 1.48749 70.44
5 200.0000 (d5)
6* 124.6600 1.4500 1.85135 40.10
7* 20.2700 6.1100
8 -45.1800 0.9000 1.59282 68.62
9 19.3100 5.4900 1.77047 29.74
10 -80.9100 2.6800
11 -23.3000 0.9000 1.49700 81.61
12 -116.6300 (d12)
13 (Aperture) ∞ 1.2000
14 45.1600 6.6100 1.61997 63.88
15 -102.3600 0.1500
16 40.5700 7.2700 1.43700 95.10
17 -22.6300 0.8500 1.83400 37.34
18 ∞ (d18)
19 25.4100 8.3300 1.43700 95.10
20 -32.1700 0.3500
21* -1000.0000 2.5500 1.59201 67.02
22* -47.8600 1.9000
23* 200.0000 1.1500 1.69350 53.20
24* 29.3900 (d24)
25 66.8200 6.4300 1.88300 40.80
26 -44.4000 1.0000 1.60342 38.01
27 77.9900 (d27)
28 -36.2300 1.0000 1.55032 75.50
29∞ (BF)
Image plane ∞

[Aspheric data]
6 faces 7 faces 21 faces 22 faces
K 0.00000 -1.00000 0.00000 0.00000
A4 1.63670E-05 3.37600E-05 -4.03330E-05 -9.20190E-06
A6 -7.28320E-08 -1.02430E-07 -7.91220E-08 -2.76630E-08
A8 2.84010E-10 2.07750E-09 2.24470E-09 1.87710E-09
A10 -4.84440E-13 -2.27040E-11 -6.19230E-12 -4.55300E-12
A12 2.85510E-16 1.41420E-13
A14-3.30980E-16

23 planes 24 planes
K 0.00000 0.00000
A4 2.11780E-05 2.02680E-05
A6 -1.86760E-07 -1.99860E-07
A8 6.66230E-10 8.20790E-10

[Various data]
Zoom ratio 2.35
Wide Angle Medium Telephoto Focal Length 28.80 40.04 67.70
F number 2.92 2.92 2.92
Full angle of view 2ω 76.09 56.05 33.85
Image height Y 21.63 21.63 21.63
Total lens length 124.97 131.84 148.73

[Variable interval data]
wide-angle medium-telephoto
d5 1.5000 9.4900 25.0700
d12 12.8500 7.5600 1.5700
d18 7.3800 4.6500 2.3100
d24 7.6800 13.9000 22.9000
d27 5.9300 6.6116 7.2820
BF 19.6225 19.6179 19.5881

[Lens group data]
Group Starting surface Focal length
G1 1 99.59
G2 6 -19.71
G3 14 63.70
G4 19 40.76
G5 25 83.81
G6 28-65.83

G41 19 33.98
G42 21 84.82
RF2 25 83.81
RR2 28 -65.83

[Value corresponding to conditional expression]
Conditional expression Example 1 Example 2 Example 3
(1) fF/f4 -1.17 -0.90 -0.99
(2) f3/f4 1.6214 1.2100 1.4151
(3) f1/f2 -6.3257 -6.0437 -5.8093
(4) νd1n 17.98 16.48 20.88
(5) νd1p 70.44 95.1 95.1
(6) νd1p/νd1n 3.92 5.77 4.55
(7) f41/f42 0.46 0.42 0.39
(8) 1/fR 0.002006 0.00019
(9) 1/fR -0.001002
(10) fRF1/fRR1 -1.3558 -0.2768 -1.0932
(11) fRF2/fRR2
(12) RWD/RTD

Conditional expression Example 4 Example 5 Example 6
(1) fF/f4 -1.14 -1.31 -1.22
(2) f3/f4 1.9915 1.8269 1.5627
(3) f1/f2 -5.8498 -4.8840 -5.0534
(4) νd1n 20.88 17.98 17.98
(5) νd1p 95.1 70.44 70.44
(6) νd1p/νd1n 4.55 3.92 3.92
(7) f41/f42 0.35 0.45 0.40
(8) 1/fR
(9) 1/fR -0.00227 -0.003255 -0.001315
(10) fRF1/fRR1 -0.5263 -1.4534
(11) fRF2/fRR2 -1.273
(12) RWD/RTD 0.914

G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group GR Rear lens group

LF focusing lens

S aperture diaphragm I image plane

Claims (10)

From the object side, the first lens group with positive refractive power, the second lens group with negative refractive power, the third lens group with positive refractive power, the fourth lens group with positive refractive power, and the rear lens group become,
The fourth lens group has a focusing lens LF consisting of a negative meniscus lens with a convex surface facing the object side that moves toward the image plane side when focusing from an infinite object to a short distance object,
During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the third lens group decreases. the distance between the lens group and the fourth lens group decreases and the distance between the fourth lens group and the rear lens group increases;
The fourth lens group comprises, in order from the object side, a lens group G41 having at least one positive lens and having positive refractive power as a whole, a positive lens G42 having an aspherical surface, and the focusing lens LF,
A large-aperture zoom lens that satisfies the following conditional expression.
(1) -2.0<fF/f4<-0.5
(7) 0.3<f41/f42<0.6
fF: focal length of the focusing lens LF f4: focal length of the fourth lens group
f41: focal length of the lens group G41
f42: focal length of the positive lens G42 2. The large lens system according to claim 1, wherein said rear lens group comprises two lens groups, and the distance between said two lens groups increases during zooming from the wide-angle end to the telephoto end. aperture zoom lens. 3. The lens according to claim 1, wherein the lens closest to the image plane in the rear lens group is fixed with respect to the image plane during zooming from the wide-angle end to the telephoto end. Large aperture zoom lens. During zooming from the wide-angle end to the telephoto end, the third lens group and the fourth lens group move toward the object side,
4. The large aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(2) 0.7<f3/f4<3.0
f3: focal length of the third lens group f4: focal length of the fourth lens group During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the object side,
5. The large-aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(3) -10.0<f1/f2<-3.0
f1: focal length of the first lens group f2: focal length of the second lens group The first lens group includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side;
Consisting of a positive lens L12 with a convex surface facing the object side and a positive lens L13 with a convex surface facing the object side,
6. The large-aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(4) νd1n<24.0
(5) 65.0<νd1p
(6) 3.0<νd1p/νd1n
νd1n: Abbe number of the negative meniscus lens L11 νd1p: Abbe number of the positive lens having the lowest dispersion among the positive lens L12 and the positive lens L13 When the rear lens group has a positive refractive power,
7. The large-aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(8) 0.0<1/fRW<0.3
fRW: focal length of the rear lens group at the wide-angle end When the rear lens group has negative refractive power,
7. The large-aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(9) -0.3<1/fRW<0.0
fRW: focal length of the rear lens group at the wide-angle end When the rear lens group consists of one lens group,
The rear lens group has a lens unit RF1 having a positive lens with a convex surface facing the object side closest to the object and having positive refractive power as a whole, and at least one negative lens closest to the image side. having a lens unit RR1 having negative refractive power as a whole;
9. The large aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(10) -3.0<fRF1/fRR1<0
fRF1: focal length of the lens unit RF1 fRR1: focal length of the lens unit RR1 When the rear lens group consists of two or more lens groups,
The rear lens group has a lens group RF2 having a positive lens with a convex surface facing the object side closest to the object and having positive refractive power as a whole, and at least one negative lens closest to the image side. having a lens group RR2 having negative refractive power as a whole,
The distance between the lens group RF2 and the lens group RR2 increases during zooming from the wide-angle end to the telephoto end,
9. The large aperture zoom lens according to claim 1, wherein the following conditional expression is satisfied.
(11) -3.0<fRF2/fRR2<0
(12) 0.5<RWD/RTD<1.0
fRF2: focal length of the lens group RF2 fRR2: focal length of the lens group RR2 RWD: composite thickness on the optical axis of the rear lens group at the wide-angle end RTD: on the optical axis of the rear lens group at the telephoto end Synthetic thickness

Images