JP6723796B2 - Zoom lens and imaging device having the same - Google Patents

Description

The present invention relates to a zoom lens, and is suitable as an image pickup optical system of an image pickup apparatus such as a digital still camera, a video camera, a TV camera, and a surveillance camera.

In recent years, as an image pickup optical system used for an image pickup apparatus using a solid-state image pickup element, a bright (small F number) zoom lens having a wide angle of view and high optical performance up to the periphery of the screen is required. A negative lead type zoom lens in which a lens group having a negative refractive power precedes (is positioned closest to the object side) is known as a zoom lens having a wide angle of view with a total field angle of imaging of about 100 degrees (Patent Document 1). 2).

In Patent Document 1, there is provided a four-group zoom lens that includes, in order from the object side to the image side, first to fourth lens groups having negative, positive, negative, and positive refracting powers, and the distance between adjacent lens groups changes during zooming. Disclosure. Patent Document 1 discloses a zoom lens having an imaging field angle at the wide-angle end of 105 degrees, a zoom ratio of 2.1, and an F number of 2.9.

In Patent Document 2, the first lens group to the fifth lens group having negative, positive, positive, negative, and positive refractive powers are arranged in this order from the object side to the image side, and the distance between adjacent lens groups changes during zooming. A group zoom lens is disclosed. Patent Document 2 discloses a zoom lens having an imaging field angle at the wide-angle end of 105 degrees, a zoom ratio of 2.1 times, and an F number of 2.9 to 4.1.

JP, 2008-046208, A JP, 2014-206674, A

A negative lead type zoom lens in which a lens unit having a negative refractive power precedes has a feature that a wide angle of view can be relatively easily obtained and a long back focus can be easily obtained. However, since the negative lead type zoom lens has an asymmetric lens configuration with respect to the aperture stop, it is difficult to correct various aberrations, and it is very difficult to obtain high optical performance while achieving a wide angle of view. It is important to properly set the lens configuration and zoom type of each lens group that makes up the zoom lens in order to reduce the occurrence of various aberrations when achieving a wide angle of view and to obtain good optical performance. Come on.

For example, in a negative lead type large-aperture (small F number) zoom lens, the incident height of an axial ray is in the rear group (a lens system arranged on the image side of the first lens group having negative refractive power). Become higher at. Therefore, in order to achieve a wide angle of view and a large aperture ratio, it is important to properly set the lens configuration of the rear group. If the lens configuration of the rear group is inappropriate, various aberrations, especially spherical aberration, increase, and it becomes very difficult to obtain high optical performance while achieving a wide angle of view.

It is an object of the present invention to provide a zoom lens having a wide angle of view, a large aperture ratio and high optical performance in the entire zoom range, and an image pickup apparatus having the zoom lens.

A zoom lens according to one aspect of the present invention comprises a first lens group having a negative refracting power and a rear group having a positive refracting power as a whole, which are arranged in order from an object side to an image side and have a plurality of lens groups. is constructed, a zoom lens spacing group adjacent lens changes the zooming, the first lens group, disposed in order from the object side to the image side, a negative lens, a negative lens, a negative lens, a positive lens The plurality of lens groups are arranged in order from the object side to the image side. The second lens group has a positive refractive power, the second lens group has a negative refractive power, the second lens group has a negative refractive power, and the second lens group has a positive refractive power. The second b lens group includes a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are sequentially arranged from the object side to the image side, and the focal length of the negative lens LN1 is fN1 at the wide angle end. When the focal length of the zoom lens is fw,
1.0<-fN1/fw<2.8
It is characterized by satisfying the following conditional expression.

According to the present invention, it is possible to obtain a zoom lens having a wide angle of view, a large aperture ratio, and high optical performance in the entire zoom range.

Example 1 Lens cross-sectional view of the present invention (A), (B) Longitudinal aberration diagrams at the wide-angle end and the telephoto end when the object distance is infinity in Example 1. Example 2 Lens Sectional View of the Present Invention (A), (B) Vertical aberration diagrams at the wide-angle end and the telephoto end when the object distance is infinity according to the second embodiment. Example 3 Lens Sectional View of the Present Invention (A), (B) Longitudinal aberration diagrams at the wide-angle end and the telephoto end when the object distance is infinity according to the third embodiment. Explanatory drawing of a main part of an image pickup apparatus of the present invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The zoom lens of the present invention has a positive lens group having a positive refractive power as a whole including a front lens group including a first lens group having a negative refractive power and arranged in order from the object side to the image side, and a plurality of lens groups. It is composed of a rear group. During zooming, the distance between adjacent lens groups changes. The plurality of lens groups included in the rear group include, in order from the object side to the image side, a positive refractive power 2a lens group, a negative refractive power 2b lens group, and a positive refractive power 2c lens group. A lens group is included.

FIG. 1 is a lens cross-sectional view at a wide-angle end (short focal length end) of a zoom lens according to a first exemplary embodiment of the present invention. FIGS. 2A and 2B are aberration diagrams at the wide-angle end and the telephoto end (long focal length end) of the zoom lens of Embodiment 1, respectively. The first embodiment is a five-group zoom lens having an imaging field angle at the wide-angle end of 105.4 degrees, an F number of 2.91, and a zoom ratio of 2.06.

FIG. 3 is a lens cross-sectional view at a wide-angle end of a zoom lens according to a second exemplary embodiment of the present invention. FIGS. 4A and 4B are aberration diagrams at the wide-angle end and the telephoto end of the zoom lens according to the second embodiment, respectively. The second embodiment is a five-group zoom lens having an imaging field angle of 105.4 degrees at the wide-angle end, an F number of 2.90 to 2.93, and a zoom ratio of 2.06.

FIG. 5 is a lens cross-sectional view at a wide-angle end of a zoom lens according to a third exemplary embodiment of the present invention. FIGS. 6A and 6B are aberration diagrams at the wide-angle end and the telephoto end of the zoom lens according to the third embodiment, respectively. The third embodiment is a five-group zoom lens having an imaging field angle at the wide-angle end of 105.7 degrees, an F number of 4.12, and a zoom ratio of 2.42. FIG. 7 is a schematic view of a main part of a digital still camera (imaging device) including the zoom lens of the present invention. In the lens cross-sectional view, the left side is the object side (front side) and the right side is the image side (rear side).

In the lens cross-sectional view, LF is the front group. The front lens group LF includes the first lens unit L1 having a negative refractive power. The LR is a rear group including one or more lens groups and having a positive refractive power as a whole. The rear group LR has a twentieth lens group L20 having a positive refractive power, a second a lens group L2a having a positive refractive power, a second b lens group L2b having a negative refractive power, and a second c lens group L2c having a positive refractive power. ing. SP is an F-number determining member (hereinafter referred to as “aperture stop”) that acts as an aperture stop that determines (limits) an open F-number (Fno) light flux.

VSP, VSP1 and VSP2 are flare cut diaphragms whose aperture diameter is changed by zooming for cutting flare light. VS is a flare cut diaphragm that cuts flare light and has a constant aperture diameter. IP is an image plane, and when used as an image pickup optical system of a video camera or a digital still camera, an image pickup surface of a solid-state image pickup element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is placed.

Further, when it is used as a photographing optical system of a silver salt film camera, a photosensitive surface corresponding to the film surface is placed. In the spherical aberration diagram, d of the solid line is the d line (wavelength 587.6 nm), and g of the chain double-dashed line is the g line (wavelength 435.8 nm). In the astigmatism diagram, the dotted line M represents the d-line meridional image plane, and the solid line S represents the d-line sagittal image plane. Further, the chromatic aberration of magnification represents the difference between the g-line and the d-line.

Fno is the F number. ω is a half angle of view (degree). In each of the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the variable power lens group is located at both ends of the mechanism which are movable on the optical axis. In the lens cross-sectional views, arrows indicate the movement loci of the respective lens groups during zooming from the wide-angle end to the telephoto end. Further, the arrow regarding Focus indicates the moving direction of the lens group when focusing from infinity to a short distance.

The zoom lens of the present invention achieves a large aperture ratio zoom lens with a maximum imaging field angle of more than 100° and a zoom ratio of 2 or more by appropriately setting the lens configurations of the front lens group LF and the rear lens group LR. There is.

The zoom lens of the present invention comprises, in order from the object side to the image side, a front lens group LF including a lens group having a negative refractive power, one or more lens groups, and a rear lens group LR having a positive refractive power as a whole. ing. The distance between the front lens group LF and the rear lens group LR is smaller at the telephoto end than at the wide angle end. During zooming, the distance between adjacent lens groups changes. By adopting a retrofocus type refractive power arrangement at the wide-angle end, a back focus having a predetermined length is obtained at the wide-angle end.

The rear group LR includes, in order from the object side to the image side, a twentieth lens group (second lens group) L20 having a positive refractive power, a second lens group (third lens group) L2a having a positive refractive power, and a negative refractive power. 2b lens group (4th lens group) L2b, and 2c lens group (5th lens group) L2c having a positive refractive power. The distance between the twentieth lens unit L20 and the second-a lens unit L2a changes at the telephoto end as compared with the wide-angle end. Zooming is performed by moving each lens group so that the second-a lens group L2a and the second-b lens group L2b are large and the distance between the second-b lens group L2b and the second-c lens group L2c is small.

As a result, the rear lens group LR has a zooming effect to ensure a predetermined zoom ratio. Further, by providing the rear group LR with a zooming effect, the relative movement amount of the front group LF and the rear group LR due to zooming is reduced. The 20th lens unit L20 moves toward the image side during focusing from infinity to a short distance.

The zoom lens of the present invention has a wide angle of view and a large aperture, but various aberrations, particularly spherical aberration, are well corrected. In order to achieve a wide angle of view, a retrofocus type in which a front lens unit having a negative refractive power is disposed on the object side and a rear lens unit having a positive refractive power is disposed on the image side is basically advantageous. Here, the refracting power of the front group is φ1, the refracting power of the rear group is φ2, and the principal point distance between the front group and the rear group is e. At this time, the refractive power Φ of the entire system is as follows.
Φ=Φ1+Φ2-e×Φ1×Φ2

If the refracting power Φ1 and the refracting power Φ2 are weakened at the same time (the absolute value is reduced) and the interval e is widened, the refracting power of each group can be weakened while ensuring the refracting power of the entire system.

Next, the lens configuration of the rear group of the positive refractive power of the zoom lens of the present invention will be described. If the refracting power Φ2 of the rear group is weakened, the converging refractive power is weakened, so that the rear group is arranged at a position away from the image plane. Further, in order to obtain a high zoom ratio, the rear lens group includes a second lens group L2a having a positive refractive power, a second lens group L2b having a negative refractive power, and a second lens group L2c having a positive refractive power in succession. Constitute. During zooming, the distance between the second-a lens unit L2a and the second-b lens unit L2b is widened, and the distance between the second-b lens unit L2b and the second-c lens unit L2c is narrowed.

In that case, it is advantageous for the lens design at the telephoto end to arrange the second-a lens unit L2a and the second-b lens unit L2b at the wide-angle end as close as possible to the physical limit. However, if the second-b lens unit L2b having a negative refractive power is closely packed in the second-c lens unit L2c having a positive refractive power, the principal point of the rear lens unit having the positive refractive power is shifted to the image side, and The power is getting stronger.

Therefore, in the retrofocus type zoom lens, the inventor of the present invention is able to physically close the distance between the second-a lens group L2a and the second-b lens group L2b to the limit while ensuring the principal point distance. Relax your power. Then, they have found that it is important to reduce various aberrations, especially spherical aberration.

Specifically, the second-b lens unit L2b having a negative refractive power has a lens configuration of a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are sequentially arranged from the object side to the image side. The focal length of the negative lens LN1 is fN1, and the focal length of the entire system (zoom lens) at the wide-angle end is fw. At this time,
1.0<-fN1/fw<2.8 (1)
It has been found that it is better to satisfy the following conditional expression.

By doing so, the front principal point position of the second-b lens unit L2b having a negative refractive power can be located on the image side, and the distance between the second-a lens unit L2a and the second-b lens unit L2b is substantially widened. become. The refractive power of the rear lens group LR having a positive refractive power is weakened so that the rear lens group LR can be easily arranged at a position distant from the image plane.

Here, by further disposing a negative lens element on the object side of the second-b lens unit L2b having a negative refractive power or disposing a positive lens element on the image side, the principal point position can be further separated. Will be easier. However, in that case, the lens group becomes thicker, and the amount of change in the distance between the second b lens group L2b and the second c lens group L2c becomes smaller, which is not preferable.

If the negative refractive power of the negative lens LN1 is too loose beyond the upper limit of the conditional expression (1), the principal point position of the second-b lens unit L2b having the negative refractive power will be closer to the object side, which is preferable. Absent. If the lower limit of conditional expression (1) is exceeded, spherical aberration at the telephoto end and field curvature at the wide-angle end are excessively corrected, which is not preferable.

More preferably, the numerical range of conditional expression (1) should be set as follows.
1.2<-fN1/fw<2.5 (1a)
More preferably, the numerical range of conditional expression (1a) should be set as follows.
1.3<-fN1/fw<2.3 (1b)

Next, a more preferable configuration for carrying out the present invention will be described. The back focus at the wide-angle end is Sk. The amount of change in the distance between the second-b lens unit L2b and the second-c lens unit L2c during zooming from the wide-angle end to the telephoto end is Dpnwt.

The refractive index and the Abbe number of the material of the negative lens LN1 are Ndn1 and νdn1, respectively. The refractive index and the Abbe number of the material of the positive lens LP1 are Ndp1 and νdp1, respectively. The refractive index and the Abbe number of the material of the negative lens LN2 are Ndn2 and νdn2, respectively. The focal length of the first lens unit L1 is f1, the focal length of the second b lens unit L2b is f2b, and the focal length of the second c lens unit L2c is f2c.

At this time, it is preferable to satisfy at least one of the following conditional expressions.
1.5<Sk/fw<5.0 (2)
0.2<-Dpnwt/fw<2.0 (3)
1.7<Ndn1<2.1 (4)
1.7<Ndp1<2.0 (5)
1.7<Ndn2<2.1 (6)
25.0<νdn1<50.0 (7)
18.0<νdp1<30.0 (8)
30.0<νdn2<45.0 (9)
0.8<-f1/fw<2.5 (10)
1.2<-f2b/fw<5.0 (11)
1.5<f2c/fw<5.0 (12)

Next, the above-mentioned conditional expressions and technical meanings will be described. Conditional expression (2) is for ensuring a sufficient space for disposing optical members such as a quick return mirror and a filter on the image side of the zoom lens. If the back focus deviates from the lower limit of conditional expression (2) and the back focus is too short, it becomes difficult to dispose the optical member. If the back focus deviates from the upper limit of conditional expression (2) and the back focus is too long, the moving range of each lens group is limited, so that the refracting power of each lens group becomes strong and various aberrations, particularly spherical aberration, increase. It is not preferable because

More preferably, the numerical range of conditional expression (2) should be set as follows.
1.8<Sk/fw<4.0 (2a)
More preferably, the numerical range of conditional expression (2a) should be set as follows.
2.0<Sk/fw<3.0 (2b)

Conditional expression (3) makes the distance between the 2b-th lens unit L2b and the 2c-th lens unit L2c appropriate during zooming from the wide-angle end to the telephoto end, and reduces fluctuations in various aberrations during zooming, especially fluctuations in spherical aberration. , To reduce the size of the entire system. If the distance Dpnwt is too wide beyond the upper limit of conditional expression (3), the entire system becomes large, which is not preferable. If the distance Dpnwt is too narrow beyond the lower limit of conditional expression (3), the refracting power of each lens group becomes strong and spherical aberration increases, which is not preferable.

More preferably, the numerical range of conditional expression (3) should be set as follows.
0.3<-Dpnwt/fw<1.6 (3a)
More preferably, the numerical range of conditional expression (3a) should be set as follows.
0.4<-Dpnwt/fw<1.2 (3b)

Conditional expressions (4), (5), and (6) are mainly for reducing various Petzval sums and for improving various aberrations, particularly spherical aberration. Materials that deviate from the upper limits of conditional expressions (4) and (6) are not preferable because lens processing becomes difficult. If the lower limits of conditional expressions (4) and (6) are exceeded, the Petzval sum of the entire system will increase, which is not preferable. If the upper limit of conditional expression (5) is exceeded, spherical aberration will increase, which is not preferable. If the lower limit of conditional expression (5) is exceeded, spherical aberration will be undercorrected, which is not preferable.

Conditional expressions (7), (8), and (9) are for reducing chromatic aberration caused by the second-b lens unit L2b having a negative refractive power, and a high-dispersion material is used for the positive lens and It stipulates that relatively low dispersion materials be used. If the upper limit values of conditional expressions (7) and (9) are deviated, chromatic aberration is insufficiently corrected, which is not preferable. If the lower limit values of conditional expressions (7) and (9) are exceeded, chromatic aberration is overcorrected, which is not preferable. When the value exceeds the upper limit of conditional expression (8), the amount of chromatic aberration in the positive lens LP1 becomes insufficient, which is not preferable. If the lower limit of conditional expression (8) is exceeded, chromatic aberration in the positive lens LP1 increases, which is not preferable.

Conditional expressions (10), (11), and (12) optimize the refracting power of the first lens unit L1, the refracting power of the second b lens unit L2b, and the refracting power of the second c lens unit L2c to reduce the size of the entire system. It is intended to satisfactorily correct various aberrations while achieving the above. If the negative refracting power of the first lens unit L1 is too weak (absolute value of the negative refracting power is too small) beyond the upper limit of the conditional expression (10), the entire system becomes large. Not good.

If the negative refractive power of the first lens unit L1 is too strong beyond the lower limit of conditional expression (10), the generation of distortion increases, which is not preferable. If the upper limit of conditional expression (11) is exceeded and the negative refractive power of the second-b lens unit L2b is too weak, the variable power effect is weakened and the overall system becomes large, which is not preferable.

If the negative refracting power of the 2b-th lens unit L2b is too strong beyond the lower limit of conditional expression (11), spherical aberration during zooming will increase significantly, which is not preferable.

If the positive refractive power of the second-c lens unit L2c is too weak beyond the upper limit of the conditional expression (12), the entire system becomes large, which is not preferable. If the positive refractive power of the second-c lens unit L2c is too strong beyond the lower limit of conditional expression (12), spherical aberration will increase over the entire zoom range, which is not preferable.

More preferably, the numerical ranges of conditional expressions (4) to (12) should be set as follows.
1.75<Ndn1<2.00 (4a)
1.75<Ndp1<1.95 (5a)
1.75<Ndn2<2.00 (6a)
28.0<νdn1<46.0 (7a)
19.0<νdp1<28.0 (8a)
32.0<νdn2<43.0 (9a)
1.0<-f1/fw<2.0 (10a)
1.5<-f2b/fw<4.0 (11a)
2.0<f2c/fw<4.0 (12a)

More preferably, the numerical ranges of conditional expressions (4a) to (12a) should be set as follows.
1.80<Ndn1<1.95 (4b)
1.78<Ndp1<1.90 (5b)
1.80<Ndn2<1.95 (6b)
30.0<νdn1<44.0 (7b)
20.0<νdp1<25.0 (8b)
34.0<νdn2<40.0 (9b)
1.2<-f1/fw<1.8 (10b)
1.8<-f2b/fw<3.5 (11b)
2.2<f2c/fw<3.0 (12b)

In the zoom lens of the present invention, in terms of aberration correction, the negative lens LN1 has a biconcave shape ( a shape with concave surfaces facing the object side and the image side ), the positive lens LP1 has a biconvex shape, and the negative lens LN2 has a biconcave shape. Is good. A cemented lens in which the positive lens LP1 and the negative lens LN2 are cemented is good. By making the negative lens LN1 biconcave, it becomes easy to increase the negative refracting power of the negative lens LN1. By cementing the positive lens LP1 and the negative lens LN2, it is possible to increase the curvature of the cemented lens surface, which facilitates correction of chromatic aberration.

In each conditional expression, the lens configurations of the front lens group LF and the rear lens group LR are as follows. The rear group LR includes, in order from the object side to the image side, a twentieth lens group L20 having a positive refractive power, a second lens group L2a having a positive refractive power, a second lens group L2b having a negative refractive power, and a positive lens group L2b. The second lens group L2c having a refractive power of 2c. When zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves toward the image side along a convex locus, and the twentieth lens unit L20 moves toward the object side along a convex locus, and the second lens unit L2a. The L2a, the 2b-th lens group L2b, and the 2c-th lens group L2c all move to the object side.

Upon focusing from infinity to short distance, the twentieth lens unit L20 moves to the image side. The first lens unit L1 is composed of a negative lens, a negative lens, a negative lens, and a positive lens, which are sequentially arranged from the object side to the image side. The twentieth lens group L20 is composed of a positive lens arranged in order from the object side to the image side, and a cemented lens in which a negative lens and a positive lens are cemented. The 2a-th lens unit L2a is composed of a cemented lens in which a negative lens and a positive lens are cemented. Alternatively, the 2a-th lens unit L2a includes a positive lens.

The second-c lens unit L2c includes a cemented lens (a first cemented lens) in which a positive lens and a negative lens are cemented, and a cemented lens (a second cemented lens) in which a negative lens and a positive lens arranged on the image side of the first cemented lens are cemented. Lens) . Alternatively, the 2c-th lens unit L2c is composed of a positive lens and a cemented lens in which a negative lens arranged on the image side of the positive lens and a positive lens are cemented.

In the present invention, by constructing each lens group as described above, a high aperture ratio, a wide angle of view, and high optical performance are obtained over the entire zoom range.

Next, an embodiment of a digital still camera (image pickup apparatus) using the zoom lens of the present invention as an image pickup optical system will be described with reference to FIG.

In FIG. 7, reference numeral 20 denotes an image pickup apparatus including the zoom lens 1 according to any one of the first to third embodiments. Reference numeral 10 is a lens body. The zoom lens 1 is held by a lens barrel 2 which is a holding member. Reference numeral 20 denotes a camera body, which includes a quick return mirror 3 that reflects the light flux from the zoom lens 1 upward, and a focusing screen 4 arranged in the image forming apparatus of the zoom lens 1. Further, it is composed of a penta roof prism 5 for converting an inverted image formed on the focusing screen 4 into an erect image, an eyepiece lens 6 for observing the erect image, and the like.

Reference numeral 7 denotes a photosensitive surface, on which a solid-state image sensor (photoelectric conversion element) that receives an image formed by a zoom lens such as a CCD sensor or a CMOS sensor and a silver salt film are arranged. At the time of shooting, the quick return mirror 3 is retracted from the optical path, and an image is formed on the photosensitive surface 7 by the zoom lens 1. The benefits described in the first to third embodiments are effectively enjoyed in the image pickup apparatus disclosed in the present embodiment. The same can be applied to a mirrorless single-lens reflex camera without the quick return mirror 3 as an imaging device.

Although the preferred embodiments of the optical system of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

Next, numerical data of each example of the present invention will be shown. In each numerical data, i indicates the order of the surface from the object side, ri is the radius of curvature of the lens surface, di is the lens thickness and the air gap between the i-th surface and the (i+1)-th surface, and ndi and νdi are respectively the The refractive index and Abbe number for the d-line of the material of the i-th lens are shown. The total lens length is the distance from the first lens surface to the image surface. The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, K is the conical constant, A4, A6, A8, A10, A12, A14. , A16 are aspherical coefficients,

It is expressed by the formula. Further, [e-X] means [ ^x10-x ]. The aspherical surface is indicated by adding * after the surface number. Further, the part where the distance d between the optical surfaces is (variable) changes during zooming. Table 1 shows the relationship between the above-mentioned conditional expressions and numerical data.

(Numerical data 1)

Unit mm

Surface data Surface number rd nd νd Effective diameter
1* ∞ 2.80 1.76385 48.5 55.29
2* 19.352 11.19 40.40
3* -209.346 2.50 1.85135 40.1 38.85
4* 161.540 7.00 33.32
5 -36.936 1.65 1.59282 68.6 33.09
6 178.705 0.15 34.25
7 74.365 5.56 1.90366 31.3 34.86
8 -89.381 (variable) 34.85
9(VSP1) ∞ 1.32 (variable)
10 92.188 2.81 1.80610 33.3 28.91
11 -233.016 0.15 29.09
12 53.209 1.40 1.84666 23.8 29.50
13 24.135 6.68 1.57501 41.5 28.77
14 244.360 (variable) 28.86
15 52.491 1.50 1.84666 23.8 29.50
16 32.501 7.68 1.51633 64.1 28.95
17 -55.396 (variable) 28.89
18(SP) ∞ 3.78 24.88
19 -54.190 1.20 1.91082 35.3 24.08
20 70.512 0.20 24.25
21 40.230 6.85 1.80809 22.8 24.72
22 -29.488 1.20 1.91082 35.3 24.57
23 95.534 3.00 24.52
24(VSP2) ∞ (variable) (variable)
25 35.229 10.56 1.49700 81.5 25.43
26 -20.032 1.20 1.83481 42.7 25.27
27 -27.733 0.15 26.45
28* 112.974 1.00 1.90366 31.3 26.67
29 27.389 6.52 1.49 700 81.5 26.72
30 -126.670 (variable) 27.50
31(VS) ∞ 30.62

Aspherical data First surface
K = 0.00000e+000 A 4= 1.11165e-005 A 6=-1.42849e-008
A 8= 1.67028e-011 A10=-1.51871e-014 A12= 2.56707e-017
A14=-2.90115e-020 A16= 1.37287e-023

Second side
K =-1.17677e+000 A 4=-3.41307e-006 A 6=-2.47447e-009
A 8= 6.17798e-011 A10=-7.84864e-013 A12= 1.56510e-015
A14= 2.15678e-019 A16=-1.47934e-021

Third side
K = 0.00000e+000 A 4=-3.78859e-005 A 6= 1.22896e-007
A 8=-1.14049e-010 A10= 7.05411e-015 A12= 2.26904e-016
A14=-1.05550e-018 A16= 1.27458e-021

Fourth side
K = 3.04868e+001 A 4=-1.84103e-005 A 6= 1.51041e-007
A 8=-1.80511e-010 A10= 6.29199e-013 A12=-2.22187e-016
A14=-3.17665e-018 A16= 3.18691e-021

Surface 28
K = 0.00000e+000 A 4=-8.91990e-006 A 6= 1.15693e-008
A 8=-2.72913e-010 A10= 1.72938e-012 A12=-3.65448e-015
A14=-1.21272e-017 A16= 5.18134e-020

Various data Zoom ratio 2.06

Wide-angle mid-telephoto focal length 16.48 24.00 33.95
F number 2.91 2.91 2.91
Half angle of view (degrees) 52.70 42.03 32.51
Image height 21.64 21.64 21.64
Total lens length 170.40 165.53 165.61
BF 38.20 47.65 62.15

d 8 28.97 11.43 0.64
d14 5.02 10.34 5.00
d17 1.20 6.08 10.13
d24 8.96 2.00 -0.38
d30 0.00 9.45 23.95

ea 9 22.86 25.88 27.37
ea24 16.16 19.46 25.00

Entrance pupil position 19.12 19.62 19.27
Exit pupil position -65.78 -47.93 -56.26
Front principal point position 32.99 36.93 41.02
Rear principal point position 21.72 14.20 4.25

Zoom lens group Data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -22.76 30.85 1.20 -26.58
2 9 67.20 12.36 0.61 -7.29
3 15 66.62 9.18 3.13 -2.93
4 18 -43.07 16.23 6.25 -5.60
5 25 42.97 19.43 4.46 -8.94

Single lens Data lens Start surface Focal length
1 1 -25.33
2 3 -106.77
3 5 -51.49
4 7 45.66
5 10 82.26
6 12 -53.35
7 13 46.06
8 15 -104.39
9 16 40.89
10 19 -33.49
11 21 22.02
12 22 -24.63
13 25 27.44
14 26 -93.01
15 28 -40.23
16 29 45.96

(Numerical data 2)

Unit mm

Surface data Surface number rd nd νd Effective diameter
1* ∞ 2.70 1.77250 49.6 56.35
2* 23.222 6.29 41.95
3* 32.416 2.40 1.85400 40.4 41.38
4* 22.207 10.33 35.29
5 -51.469 1.80 1.80400 46.6 35.20
6 297.301 1.93 35.78
7 71.476 7.20 1.62588 35.7 36.89
8 -55.168 (variable) 36.94
9 74.183 2.88 2.00100 29.1 29.59
10 -1228.374 0.15 29.38
11 51.570 1.50 1.84666 23.8 29.37
12 18.892 6.14 1.72047 34.7 27.92
13 51.045 (variable) 27.67
14 44.661 4.87 1.49700 81.5 28.23
15 -100.985 (variable) 27.76
16(SP) ∞ 3.49 (variable)
17 -75.083 1.30 1.83481 42.7 23.11
18 33.957 1.14 23.03
19 38.253 3.93 1.84666 23.8 23.66
20 -154.375 1.30 1.91082 35.3 23.68
21 134.495 3.50 23.71
22(VSP) ∞ (variable) (variable)
23 23.338 8.86 1.43875 94.9 27.78
24 -43.221 0.15 27.80
25* 80.174 1.60 1.91082 35.3 26.96
26 18.618 8.87 1.49700 81.5 26.01
27 -93.952 26.99

Aspherical data First surface
K = 0.00000e+000 A 4= 1.56496e-005 A 6=-2.19764e-008
A 8= 1.73809e-011 A10=-6.82156e-015 A12= 2.34290e-018

Second side
K = 0.00000e+000 A 4=-6.67858e-006 A 6= 1.84002e-008
A 8=-8.12830e-012 A10=-3.35187e-013 A12= 2.34815e-016

Third side
K = 0.00000e+000 A 4=-2.58947e-005 A 6= 3.64076e-008
A 8=-7.13919e-011 A10=-8.68294e-014 A12= 2.26270e-016

Fourth side
K =-1.09072e+000 A 4=-3.88760e-006 A 6= 2.17363e-008
A 8=-9.97731e-011 A10= 2.46184e-013 A12= 4.04592e-017

Surface 25
K = 0.00000e+000 A 4=-9.66009e-006 A 6=-4.68072e-009
A 8=-1.16803e-010 A10= 3.82514e-013 A12=-8.48378e-016

Various data Zoom ratio 2.06

Wide-angle mid-telephoto focal length 16.48 24.40 33.95
F number 2.90 2.90 2.93
Half angle of view (degrees) 52.70 41.56 32.51
Image height 21.64 21.64 21.64
Total lens length 172.20 160.31 156.36
BF 38.00 44.75 55.33

d 8 31.89 11.72 1.00
d13 8.24 11.35 7.37
d15 0.50 7.96 12.83
d22 11.24 2.20 -2.50

ea16 17.53 19.88 23.89
ea22 16.85 19.63 24.29

Entrance pupil position 20.51 20.97 21.02
Exit pupil position -67.53 -35.63 -25.95
Front principal point position 34.42 37.96 40.79
Rear principal point position 21.52 20.36 21.38

Zoom lens group Data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -26.71 32.65 -0.10 -32.36
2 9 85.24 10.67 -6.14 -11.24
3 14 63.00 4.87 1.01 -2.28
4 16 -48.83 14.66 3.93 -7.63
5 23 43.84 19.48 2.07 -11.56

Single lens Data lens Start surface Focal length
1 1 -30.06
2 3 -92.60
3 5 -54.44
4 7 50.86
5 9 69.97
6 11 -35.97
7 12 38.55
8 14 63.00
9 17 -27.86
10 19 36.55
11 20 -78.74
12 23 36.00
13 25 -26.96
14 26 32.10

(Numerical data 3)

Unit mm

Surface data Surface number rd nd νd Effective diameter
1* ∞ 2.70 1.77250 49.6 51.01
2* 20.329 6.37 37.38
3* 33.057 2.00 1.85400 40.4 36.83
4* 22.694 8.68 31.92
5 -46.187 1.60 1.80400 46.6 31.85
6 -659.842 0.23 32.43
7 59.759 5.73 1.62588 35.7 33.01
8 -75.064 (variable) 32.86
9 156.389 1.96 2.00100 29.1 20.98
10 -159.435 0.15 21.03
11 68.022 1.10 1.84666 23.8 21.17
12 20.312 4.83 1.72047 34.7 20.94
13 456.752 (variable) 20.96
14 36.320 3.72 1.49 700 81.5 21.42
15 -94.159 (variable) 21.21
16(SP) ∞ 0.99 (variable)
17 -84.807 0.90 1.83481 42.7 16.71
18 26.723 1.08 16.48
19 29.822 2.97 1.84666 23.8 16.90
20 -167.878 0.90 1.91082 35.3 16.83
21 54.210 1.00 16.77
22(VSP) ∞ (variable) (variable)
23 24.695 7.86 1.43875 94.9 26.74
24 -37.571 0.15 26.84
25* 101.590 1.40 1.91082 35.3 26.33
26 19.411 9.09 1.49700 81.5 25.82
27 -59.912 26.95

Aspherical data First surface
K = 0.00000e+000 A 4= 1.65876e-005 A 6=-2.22547e-008
A 8= 1.85368e-011 A10=-6.33361e-015 A12= 3.52893e-018

Second side
K = 0.00000e+000 A 4=-1.31443e-005 A 6= 1.93489e-008
A 8=-4.44235e-011 A10=-4.45049e-013 A12=-1.20204e-017

Third side
K = 0.00000e+000 A 4=-3.03298e-005 A 6= 2.59719e-008
A 8=-7.87386e-011 A10=-6.92763e-014 A12= 4.37902e-016

Fourth side
K =-1.15446e+000 A 4=-4.61358e-006 A 6= 1.99661e-008
A 8=-1.47061e-010 A10= 6.95272e-013 A12= 2.94439e-018

Surface 25
K = 0.00000e+000 A 4=-9.18468e-006 A 6=-6.81819e-009
A 8=-1.01825e-010 A10= 4.54525e-013 A12=-1.12900e-015

Various data Zoom ratio 2.42

Wide-angle mid-telephoto focal length 16.30 24.40 39.50
F number 4.12 4.12 4.12
Half angle of view (degrees) 52.83 41.38 28.56
Image height 21.50 21.50 21.50
Total lens length 155.52 144.14 143.37
BF 38.00 43.79 60.01

d 8 27.53 12.21 1.00
d13 3.78 7.28 4.22
d15 2.50 7.53 12.24
d22 18.30 7.92 0.50

ea16 11.34 12.74 16.91
ea22 10.88 12.38 16.73

Entrance pupil position 18.31 18.72 18.96
Exit pupil position -88.70 -38.03 -21.90
Front principal point position 32.52 35.85 39.41
Rear principal point position 21.70 19.39 20.51

Zoom lens group Data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -22.33 27.32 1.50 -22.70
2 9 57.28 8.04 0.14 -4.36
3 14 53.24 3.72 0.70 -1.81
4 16 -33.46 7.84 2.07 -3.45
5 23 41.46 18.49 3.48 -9.78

Single lens Data lens Start surface Focal length
1 1 -26.32
2 3 -93.04
3 5 -61.84
4 7 54.04
5 9 79.12
6 11 -34.57
7 12 29.37
8 14 53.24
9 17 -24.25
10 19 30.12
11 20 -44.90
12 23 35.32
13 25 -26.56
14 26 30.67

LF front group LR rear group L1 first lens group L20 twentieth lens group L2a second a lens group L2b second b lens group L2c second c lens group LN1 negative lens LP1 positive lens LN2 negative lens

Claims (19)

The first lens group having negative refracting power and the rear group having a positive refracting power as a whole including a plurality of lens groups, which are sequentially arranged from the object side to the image side, and are arranged between adjacent lens groups during zooming. Is a zoom lens that changes
The first lens group includes a negative lens, a negative lens, a negative lens, and a positive lens, which are sequentially arranged from the object side to the image side.
The plurality of lens groups include a positive refractive power second a lens group, a negative refractive power second b lens group, and a positive refractive power second c lens group, which are sequentially arranged from the object side to the image side.
The second-b lens group includes a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are arranged in order from the object side to the image side,
When the focal length of the negative lens LN1 is fN1 and the focal length of the zoom lens at the wide angle end is fw,
1.0<-fN1/fw<2.8
A zoom lens that satisfies the following conditional expression. The zoom lens according to claim 1, wherein the second-a lens group includes a negative lens and a positive lens cemented to each other. The first lens group having negative refracting power and the rear group having a positive refracting power as a whole including a plurality of lens groups, which are sequentially arranged from the object side to the image side, and are arranged between adjacent lens groups during zooming. Is a zoom lens that changes
The plurality of lens groups include a positive refractive power second a lens group, a negative refractive power second b lens group, and a positive refractive power second c lens group, which are sequentially arranged from the object side to the image side.
The second-a lens group includes a negative lens and a positive lens cemented to each other,
The second-b lens group includes a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are arranged in order from the object side to the image side,
When the focal length of the negative lens LN1 is fN1 and the focal length of the zoom lens at the wide angle end is fw,
1.0<-fN1/fw<2.8
A zoom lens that satisfies the following conditional expression. When the back focus of the zoom lens at the wide-angle end is Sk,
1.5<Sk/fw<5.0
The zoom lens according to any one of claims 1 to 3, wherein the following conditional expression is satisfied. The distance between the second b lens group and the second c lens group becomes smaller at the telephoto end than at the wide angle end,
When the difference between the distance between the second b lens group and the second c lens group at the wide-angle end and the distance between the second b lens group and the second c lens group at the telephoto end is Dpnwt,
0.2 <- Dpnwt / fw <2.0
The zoom lens according to any one of claims 1 to 4, wherein the zoom lens satisfies the following conditional expression. The negative lens LN1 has a concave surface facing the object side and the image side, the positive lens LP1 has a convex surface facing the object side and the image side, and the negative lens LN2 has a concave surface facing the object side and the image side. The shape is
The zoom lens according to any one of claims 1 to 5 , wherein the positive lens LP1 and the negative lens LN2 are cemented with each other . When the refractive index of the material of the negative lens LN1 is Ndn1, the refractive index of the material of the positive lens LP1 is Ndp1, and the refractive index of the material of the negative lens LN2 is Ndn2,
1.7<Ndn1<2.1
1.7<Ndp1<2.0
1.7<Ndn2<2.1
The zoom lens according to any one of claims 1 to 6, characterized by satisfying the conditional expression. When the Abbe number of the material of the negative lens LN1 is νdn1, the Abbe number of the material of the positive lens LP1 is νdp1, and the Abbe number of the material of the negative lens LN2 is νdn2,
25.0<νdn1<50.0
18.0<νdp1<30.0
30.0<νdn2<45.0
The zoom lens according to any one of claims 1 to 7 , wherein the following conditional expression is satisfied. When the focal length of the first lens group is f1,
0.8<-f1/fw<2.5
The zoom lens according to any one of claims 1 to 8, characterized by satisfying the conditional expression. When the focal length of the 2b-th lens group is f2b,
1.2<-f2b/fw<5.0
The zoom lens according to any one of claims 1 to 9 , wherein the zoom lens satisfies the following conditional expression. When the focal length of the second c lens group is f2c,
1.5<f2c/fw<5.0
The zoom lens according to any one of claims 1 to 10 , wherein the zoom lens satisfies the following conditional expression. The second c lens group includes a first cemented lens in which a positive lens and a negative lens are cemented, and a second cemented lens in which a negative lens and a positive lens are cemented, which is arranged on the image side of the first cemented lens. The zoom lens according to any one of claims 1 to 11 , wherein the zoom lens is a zoom lens. The first lens group having negative refracting power and the rear group having a positive refracting power as a whole including a plurality of lens groups, which are sequentially arranged from the object side to the image side, and are arranged between adjacent lens groups during zooming. Is a zoom lens that changes
The plurality of lens groups include a positive refractive power second a lens group, a negative refractive power second b lens group, and a positive refractive power second c lens group, which are sequentially arranged from the object side to the image side.
The second-b lens group includes a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are arranged in order from the object side to the image side,
The second c lens group includes a first cemented lens in which a positive lens and a negative lens are cemented, and a second cemented lens in which a negative lens and a positive lens are cemented, which is arranged on the image side of the first cemented lens. Is
When the focal length of the negative lens LN1 is fN1 and the focal length of the zoom lens at the wide angle end is fw,
1.0<-fN1/fw<2.8
A zoom lens that satisfies the following conditional expression. The rear group is composed of a second lens group having a positive refractive power, the second lens group a, the second lens group b , and the second lens group c arranged in this order from the object side to the image side. The zoom lens according to any one of claims 1 to 13 . During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the image side along a convex locus, the second lens group moves toward the object side along a convex locus, and the 2a lens group and the above 15. The zoom lens according to claim 14 , wherein both the second- b lens group and the second- c lens group move to the object side. The first lens group having negative refracting power and the rear group having a positive refracting power as a whole including a plurality of lens groups, which are sequentially arranged from the object side to the image side, and are arranged between adjacent lens groups during zooming. Is a zoom lens that changes
The plurality of lens groups are arranged in order from the object side to the image side, and have a positive refractive power second lens group, a positive refractive power second a lens group, a negative refractive power second b lens group, and a positive refractive power second lens group. It is composed of a second c lens group having a refractive power,
During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the image side along a convex locus, the second lens group moves toward the object side along a convex locus, and the 2a lens group and the above Both the second b lens group and the second c lens group move to the object side,
The second-b lens group includes a negative lens LN1, a positive lens LP1, and a negative lens LN2, which are arranged in order from the object side to the image side,
When the focal length of the negative lens LN1 is fN1 and the focal length of the zoom lens at the wide angle end is fw,
1.0<-fN1/fw<2.8
A zoom lens that satisfies the following conditional expression. 17. The zoom lens according to claim 14 , wherein the second lens group moves toward the image side during focusing from infinity to a short distance. The second lens group includes a positive lens, arranged on the image side of the positive lens, any one of claims 14 to 17, characterized in that it is composed of a cemented lens of a negative lens and a positive lens the zoom lens according to an item. A zoom lens according to any one of claims 1 to 18, an imaging apparatus characterized by having an image pickup device which receives an image formed by the zoom lens.