JP2018194768A - Zoom lens and imaging apparatus using the same - Google Patents

Abstract

To provide a zoom lens having favorably corrected chromatic aberration in the entire zoom range and high resolution performance while achieving reduction in size and highly variable magnifications, and an imaging apparatus using the zoom lens.SOLUTION: The zoom lens comprises, successively from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a rear group including at least one lens group, in which upon zooming from a wide angle end to a telephoto end, at least the first to third lens groups move. The second lens group has at least three negative lenses and at least one positive lens. A focal distance f2 of the second lens, a focal distance ft at the telephoto end, an average Abbe number v2nave of negative lenses included in the second lens group, and an average Abbe number v2pave of positive lenses included in the second lens group are appropriately set.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus using the same, and is suitable for a video camera, a digital camera, and the like.

  In recent years, in an imaging apparatus using a solid-state imaging element, in addition to downsizing and high functionality of the entire apparatus, there has been a strong demand for higher image quality. Accordingly, there is a strong demand for a zoom lens having a high resolving power in which chromatic aberration is well corrected, in addition to being small and highly variable, as a photographing optical system used for these.

  In order to meet such a demand, various zoom lenses have been proposed. As disclosed in Patent Documents 1 and 2, the refractive powers of the positive group, the negative group, and the positive group are sequentially increased from the object side to the image side. A positive lead type zoom lens is known. For example, as an example of improving the image quality of a small zoom lens with a zoom lens group configuration having positive and negative groups, in Patent Document 1, the focal length converted to a silver salt camera is 35 mm and the zoom ratio is 8.0 times. In addition, Patent Document 2 discloses a zoom lens with a silver salt camera equivalent focal length of 22 mm and a zoom ratio of about 11.8 times.

JP-A-9-068653 JP 2012-255893 A

  In general, in order to achieve high zoom ratio and miniaturization in a zoom lens group configuration having positive and negative groups, the refractive power of the second lens group that is the zoom group (optical power = reciprocal of focal length). It is effective to strengthen However, simply increasing the refractive power of the second lens group makes it difficult to obtain a high resolving power over the entire zoom range due to chromatic aberration generated in the second lens group. Therefore, it is necessary to correct the chromatic aberration by appropriately selecting the configuration and material of the second lens group in accordance with the refractive power setting.

  In Patent Document 1, it cannot be said that the zoom lens has a sufficient size reduction and a high zoom ratio due to the weak refractive power of the second lens group.

  Although Patent Document 2 attempts to reduce the size and increase the zoom ratio of the zoom lens by increasing the refractive power of the second lens group, it cannot be said that sufficient chromatic aberration correction is achieved throughout the entire zoom range.

  Therefore, the present invention achieves downsizing and high zooming by appropriately setting the refractive power, the number of lens components, and the material of the second lens unit in a zoom lens unit configuration having positive and negative groups. Another object of the present invention is to provide a zoom lens having a high resolution performance in which chromatic aberration is corrected well over the entire zoom range, and an imaging apparatus using the zoom lens.

To achieve the above object, a zoom lens according to the present invention provides:
A rear group including a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and at least one lens group in order from the object side to the image side. In a zoom lens in which at least the first to third lens units move during zooming from the wide-angle end to the telephoto end, at least three negative lenses and at least one negative lens are included in the second lens unit. It has a positive lens, the focal length of the second lens is f2, the focal length ft at the telephoto end, the average Abbe number of the negative lens included in the second lens group is v2nave, and the average Abbe of the positive lens included in the second lens group When the number is v2pave, the following conditional expression is satisfied.

0.050 <| f2 | / ft <0.140
40.0 <v2nave−v2pave <100.0

  According to the present invention, in a zoom lens having a positive / negative positive group, there is obtained a zoom lens having a high resolving power and a zoom lens having a high resolving power in which the chromatic aberration is corrected satisfactorily while being small in size and having a high zoom ratio, and an imaging apparatus using the same. It is done.

Lens sectional view of Numerical Example 1 of the present invention Aberration diagram at the wide angle end according to Numerical Example 1 of the present invention. Aberration diagram at intermediate position of Numerical Example 1 of the present invention Aberration diagram at the telephoto end according to Numerical Example 1 of the present invention. Lens sectional view of Numerical Example 2 of the present invention Aberration diagram at the wide angle end according to Numerical Example 2 of the present invention. Aberration diagram at intermediate position of Numerical Example 2 of the present invention Aberration diagram at the telephoto end according to Numerical Example 2 of the present invention. Lens sectional view of Numerical Example 3 of the present invention Aberration diagram at the wide angle end according to Numerical Example 3 of the present invention. Aberration diagram at intermediate position of Numerical Example 3 of the present invention Aberration diagram at the telephoto end according to Numerical Example 3 of the present invention Lens sectional view of Numerical Example 4 of the present invention Aberration diagram at the wide angle end according to Numerical Example 4 of the present invention. Aberration diagram at intermediate position of Numerical Example 4 of the present invention Aberration diagram at the telephoto end according to Numerical Example 4 of the present invention. Lens sectional view of Numerical Example 5 of the present invention Aberration diagram at the wide-angle end according to Numerical Example 5 of the present invention Aberration diagram at intermediate position of Numerical Example 5 of the present invention Aberration diagram at the telephoto end according to Numerical Example 5 of the present invention. Lens sectional drawing of Numerical Example 6 of the present invention Aberration diagram at the wide angle end according to Numerical Example 6 of the present invention. Aberration diagram at intermediate position of Numerical Example 6 according to the present invention Aberration diagram at the telephoto end according to Numerical Example 6 of the present invention. Schematic diagram of the optical apparatus of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 1 of the present invention. 2, 3, and 4 are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) of the zoom lens of Example 1, respectively. Embodiment 1 is a zoom lens having a zoom ratio of 11.8 and an aperture ratio of about 2.88 to 2.88.

  FIG. 5 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to the second embodiment of the present invention. 6, 7 and 8 are aberration diagrams of the zoom lens of Example 2 at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively. The second embodiment is a zoom lens having a zoom ratio of 12.6 and an aperture ratio of about 2.88 to 3.00.

  FIG. 9 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 3 of the present invention. 10, 11 and 12 are aberration diagrams of the zoom lens of Example 3 at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively. Example 3 is a zoom lens having a zoom ratio of 13.2 and an aperture ratio of about 2.88 to 3.50.

  FIG. 13 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to the fourth exemplary embodiment of the present invention. FIGS. 14, 15, and 16 are aberration diagrams of the zoom lens of Example 4 at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively. The fourth embodiment is a zoom lens having a zoom ratio of 13.7 and an aperture ratio of about 2.88 to 4.00.

  FIG. 17 is a lens cross-sectional view at the wide-angle end (short focal length end) of a zoom lens according to Example 5 of the present invention. 18, 19 and 20 are aberration diagrams of the zoom lens of Example 5 at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively. Example 5 is a zoom lens having a zoom ratio of 14.3 and an aperture ratio of about 2.88 to 5.60.

  FIG. 21 is a lens cross-sectional view at the wide-angle end (short focal length end) of a zoom lens according to Example 6 of the present invention. FIGS. 22, 23, and 24 are aberration diagrams of the zoom lens of Example 6 at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively. Example 6 is a zoom lens having a zoom ratio of 11.1 and an aperture ratio of about 2.88 to 5.60.

  In the lens cross-sectional view, i indicates the order of the lens groups from the object side to the image side, and Li is the i-th lens group. SP is an F-number determining member (hereinafter referred to as “aperture stop”) that functions as an aperture stop that determines (limits) an open F-number (Fno) light beam. G is an optical block corresponding to an optical filter, a face plate, a crystal low-pass filter, an infrared cut filter, or the like. IP is an image plane, and when used as a photographing optical system of a video camera or a digital still camera, an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is placed. Further, when used as a photographing optical system for a silver salt film camera, a photosensitive surface corresponding to the film surface is provided.

  In the aberration diagrams, d and F represent d-line and g-line, respectively, and ΔM and ΔS represent a meridional image plane and a sagittal image plane, respectively. On-axis and lateral chromatic aberration are represented by g-line.

  Next, points common to the embodiments will be described for obtaining the effects of the present invention. A rear group including a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and at least one lens group in order from the object side to the image side. In a zoom lens in which at least the first to third lens units move during zooming from the wide-angle end to the telephoto end, at least three negative lenses and at least one negative lens are included in the second lens unit. It is configured with a positive lens and satisfies the following conditions.

0.050 <| f2 | / ft <0.140 (1)
40.0 <v2nave−v2pave <100.0 (2)
However, the focal length of the second lens is f2, the focal length ft at the telephoto end, the average Abbe number of the negative lens included in the second lens group is v2nave, and the average Abbe number of the positive lens included in the second lens group is v2pave. .

  In the present invention, zooming is performed mainly by moving the second lens group and the third lens group. In particular, by increasing the refracting power of the second lens group, the zooming effect of the second lens group is enhanced and the movement amount during zooming is suppressed, thereby achieving high zooming and miniaturization.

  Further, by making the number of negative lenses included in the second lens group three or more, the refractive power is shared, and the average Abbe number difference between the negative lens and the positive lens included in the second lens group is appropriately set. By setting, the chromatic aberration generated when the refractive power of the second lens group is increased is corrected.

  If the conditional expression (1) exceeds the upper limit, the refractive power of the second lens group becomes too weak, and the amount of movement of the second group becomes too large at the time of high zooming, thereby reducing the overall length of the zoom lens. It becomes difficult. If the lower limit is exceeded, the refractive power of the second lens group becomes too strong, and it becomes difficult to correct axial chromatic aberration at the telephoto end.

  Conditional expression (2) is an expression that defines the difference between the average Abbe numbers of the negative lenses included in the second lens group and the average Abbe numbers of the positive lenses included in the second lens group. The larger the Abbe number difference between the negative lens and the positive lens included in the second lens group, the smaller the refractive power of each lens necessary for the primary color correction.

  If conditional expression (2) exceeds the upper limit, it is advantageous for primary color correction. However, in the case of an actual material, the difference in partial dispersion ratio between the negative lens and the positive lens becomes too large. Increasing the next spectrum becomes a problem. If the lower limit is exceeded, the difference in Abbe number becomes too small, and the refractive power of each lens necessary for the primary color correction becomes too large. As a result, it becomes difficult to correct curvature of field at the wide-angle end and spherical aberration on the telephoto side.

  By satisfying the above-described configuration and the conditions (1) and (2), the zoom lens having a high resolving power in which the chromatic aberration is corrected in the entire zoom range, which is a subject of the present invention, is small and has a high zoom ratio. It becomes possible to do.

  Still more preferably, in order to increase the effect of the embodiment, it is preferable to set the ranges of conditional expressions (1) and (2) to the following ranges.

0.070 <| f2 | / ft <0.135 (1a)
41.0 <v2nave−v2pave <80 (2a)
More preferably, the ranges of conditional expressions (1a) and (2a) are set to the following ranges.

0.090 <| f2 | / ft <0.135 (1b)
42 <v2nave−v2pave <75 (2b)
Furthermore, when the lateral magnification of the second lens group at the wide-angle end is β2w and the lateral magnification at the telephoto end is β2t, it is preferable that the following conditional expression is satisfied.

4.0 <β2t / β2w <10.0 (3)
If the conditional expression (3) exceeds the upper limit, the zoom ratio of the second lens group becomes too large, and it is difficult to correct the chromatic aberration of magnification over the entire zoom range if the refractive power of the second lens group is kept strong. It becomes. When the lower limit is exceeded, the zoom ratio of the second lens group becomes too small, and the zooming share due to movement of the third lens group becomes large at the time of high zooming, so when trying to maintain the same zoom ratio, It becomes difficult to reduce the total length of the telephoto end.

  Further, it is preferable that the following conditional expression is satisfied when the average focal length of the negative lens included in the second lens group is f2nave and the focal length at the wide-angle end is fw.

3.0 <| f2nave | / fw <10.0 (4)
If conditional expression (4) exceeds the upper limit, the refractive power of the negative lens included in the second lens group becomes too weak, and the effect of refracting off-axis light beams at the wide-angle end is reduced, so the front lens diameter is large. It becomes a problem to become. If the lower limit is exceeded, the refractive power of the negative lens included in the second lens group becomes too strong, and it becomes difficult to correct lateral chromatic aberration at the wide-angle end.

  Furthermore, when the average refractive index of the negative lens included in the second lens group is N2nave, it is preferable that the following conditional expression is satisfied.

1.500 <N2nave <1.800 (5)
When the conditional expression (5) exceeds the upper limit, with the actual material, the dispersion of the negative lens included in the second lens group becomes too high, making it difficult to perform the primary chromatic aberration correction. If the lower limit is exceeded, the refractive index of the negative lens included in the second lens group becomes too low, making it difficult to correct field curvature that occurs at the wide-angle end.

  Furthermore, it is preferable that the second lens group includes 21 lenses having a negative refractive power, 22 lenses having a negative refractive power, and 23 lenses having a negative refractive power in order from the object side. As described above, the arrangement of the lenses in the second lens group is such that three negative lenses are arranged from the object side, whereby the off-axis light beam can be gently refracted at the wide-angle end, and the image at the wide-angle end. Bending of chromatic aberration of magnification between high is corrected well.

  Further, the radius of curvature of the object surface of the 21 lens is R21o, the radius of curvature of the image side surface is R21i, the radius of curvature of the object side surface of the 22 lens is R22o, the radius of curvature of the image side surface of the 22 lens is R22i, and the curvature of the object side surface of the 23 lens. When the radius is R23o and the curvature radius of the image side surface of the 23 lens is R23i, it is preferable that the following conditional expression is satisfied.

0.90 <(R21o + R21i) / (R21o−R21i) <2.00 (6)
−1.00 <(R22o + R22i) / (R22o−R22i) <2.00 (7)
−3.00 <(R23o + R23i) / (R23o−R23i) <− 1.00 (8)
Conditional expression (6) is an expression that defines the shape factor of the negative lens 21 of the second lens group. When the upper limit is exceeded, the shape of the object side lens surface of the negative lens 21 becomes too tight on the convex side, and spherical aberration correction becomes excessive on the telephoto side. If the lower limit is exceeded, the shape of the object-side lens surface becomes too tight on the concave surface side, making it difficult to correct high-order lateral chromatic aberration at the wide-angle end.

  Conditional expression (7) is an expression that defines the shape factor of the negative lens 22 of the second lens group. When the upper limit is exceeded, the shape of the object side lens surface of the negative lens 22 becomes too tight on the convex side, and spherical aberration correction becomes excessive on the telephoto side. If the lower limit is exceeded, the shape of the object-side lens surface becomes too tight on the concave surface side, making it difficult to correct high-order lateral chromatic aberration at the wide-angle end.

  Conditional expression (8) is an expression that defines the shape factor of the negative lens 23 of the second lens group. If the upper limit is exceeded, the shape of the image side lens surface of the negative lens 23 becomes too tight on the concave side, and astigmatism correction becomes excessive at the wide angle end. If the lower limit is exceeded, the shape of the image side lens surface of the negative lens 23 becomes too tight on the convex side, and it becomes difficult to correct spherical aberration of colors in the short wavelength region at the telephoto end.

  Furthermore, it is preferable that the following conditional expression is satisfied when the focal length of the first lens unit is f1.

0.500 <f1 / ft <1.000 (9)
If the conditional expression (9) exceeds the upper limit, the refractive power of the first lens group becomes too weak, and the amount of movement of the first lens group increases when zooming is performed, and at the telephoto end. The overall length of the zoom lens is increased. If the lower limit is exceeded, the refractive power of the first lens group becomes too strong, and it becomes difficult to correct axial chromatic aberration at the telephoto end.
Further, the first lens group includes at least one positive lens and a negative lens. The average Abbe number of positive lenses included in the first lens group is v1pave, and the average Abbe number of negative lenses is v1nave. It is preferable that the following conditional expression is satisfied.

40.0 <v1pave−v1nave <80.0 (10)
If the conditional expression (10) exceeds the upper limit, the difference between the Abbe numbers of the positive lens and the negative lens becomes too large, and the difference in the partial dispersion ratio between the positive lens and the negative lens becomes too large with existing materials. An increase in the secondary spectrum at the telephoto end becomes a problem. If the lower limit is exceeded, the difference in Abbe number becomes too small, and the refractive power of each lens necessary for the primary color correction becomes too large. As a result, it becomes difficult to correct spherical aberration at the telephoto end.

  Furthermore, it is preferable that the following conditional expression is satisfied when the focal length of the third lens group is f3.

0.100 <f3 / ft <0.250 (11)
If the conditional expression (11) exceeds the upper limit, the refractive power of the third lens group becomes too weak, and the amount of movement of the third lens group increases when zooming is performed at the telephoto end. The overall length of the zoom lens is increased. If the lower limit is exceeded, the refractive power of the third lens group becomes too strong, and it is difficult to correct axial chromatic aberration over the entire zoom range.

  Furthermore, the third lens group includes at least one positive lens and a negative lens. The average Abbe number of positive lenses included in the third lens group is v3pave, and the average Abbe number of negative lenses is v3nave. It is preferable that the following conditional expression is satisfied.

40.0 <v3pave−v3nave <80.0 (12)
If the conditional expression (12) exceeds the upper limit, it is advantageous for primary color correction. However, with the actual material, the difference in partial dispersion ratio between the positive lens and the negative lens becomes too large, and the two at the wide-angle end. Increasing the next spectrum becomes a problem. If the lower limit is exceeded, the difference in Abbe number becomes too small, and the refractive power of each lens necessary for the primary color correction becomes too large. As a result, it is difficult to correct spherical aberration and astigmatism over the entire zoom range.

  More preferably, in order to increase the effect of the embodiment, it is preferable to set the ranges of conditional expressions (3) to (11) to the following ranges.

4.0 <β2t / β2w <7.0 (3a)
4.00 <| f2nave | / fw <7.00 (4a)
1.520 <N2nave <1.700 (5a)
0.95 <(R21o + R21i) / (R21o−R21i) <1.50 (6a)
−0.90 <(R22o + R22i) / (R22o−R22i) <1.70
... (7a)
−2.50 <(R23o + R23i) / (R23o−R23i) <− 1.50
... (8a)
0.600 <f1 / ft <0.900 (9a)
41.0 <v1pave−v1nave <75.0 (10a)
0.150 <f3 / ft <0.240 (11a)
42.0 <v3pave−v3nave <75.0 (12a)
Furthermore, the zoom lens proposed by the present invention can achieve higher performance in the entire zoom range by using it together with a system that corrects an electrical signal including distortion and lateral chromatic aberration by image processing.

  Next, details of an embodiment of the zoom lens of the present invention will be described. As a common feature of the zoom lenses of the embodiments, the lens units L1 to L3 move during zooming from the wide-angle end to the telephoto end. Specifically, at the time of zooming, the first lens unit L1 moves so as to draw a convex locus toward the image side, and is positioned closer to the object side than the wide angle end at the telephoto end. The second lens unit L2 moves to the image side. The third lens unit L3 moves to the object side. At this time, the distance between the first lens unit L1 and the second lens unit L2 is increased at the telephoto end compared to the wide-angle end. Further, the second lens unit L2 and the third lens unit L3 are moved so that the distance between them is small. In the zoom lens of each embodiment, an F-number determining member SP is provided between the second lens group L2 and the third lens group L3. The F-number determining member SP moves independently of the other lens units during zooming, and moves so as to draw a convex trajectory toward the object side in the zoom intermediate region, thereby reducing the effective diameter of the front lens. Yes.

  For the zoom lenses of Examples 1 to 5, the fourth lens unit L4 having negative refractive power and the fifth lens unit L5 having positive refractive power are arranged as a rear unit on the image side from the third lens unit. It is configured. The fourth lens unit L4 moves so as to draw a convex locus on the image side, and is positioned closer to the object side than the wide-angle end at the telephoto end. The fifth lens unit L5 moves to the image side. The correction of the focus variation accompanying zooming is realized mainly by the movement of the fourth lens unit L4 or L5. Focusing is performed by moving the fourth lens unit L4 or the fifth lens unit L5 in the optical axis direction.

  The zoom lens according to the sixth exemplary embodiment is configured by disposing a fourth lens unit L4 having a positive refractive power as a rear unit on the image side of the third lens unit. The fourth lens unit L4 moves toward the image side upon zooming from the wide-angle end to the telephoto end. Correction of focus fluctuations accompanying zooming is realized mainly by movement of the fourth lens unit L4. Focusing is performed by moving the fourth lens group in the optical axis direction.

  Hereinafter, the configuration in each lens group will be described. The first lens unit L1 includes, in order from the object side, a cemented lens 14 including a negative lens 11 and a positive lens 12, and a positive meniscus lens 13 having a convex surface directed toward the object side. With this configuration, the positive refractive power of the first lens unit L1 is shared by the cemented lens 14 and the positive lens 13, and various aberrations that occur in the first lens unit L1, particularly axial chromatic aberration on the telephoto side. The occurrence of lateral chromatic aberration is reduced.

  The second lens unit L2 includes, in order from the object side, a negative lens 21 having a strong concave surface facing the image side, a negative lens 22 having a strong concave surface facing the image side, a negative lens 23 having a strong concave surface facing the object side, and an object side. It is composed of a positive lens 24 having a convex surface. With this configuration, the negative refractive power of the second lens unit L2 is shared by the three negative lenses, and various aberrations that occur in the second lens unit L2, in particular, the chromatic aberration of magnification between the image heights on the wide angle side. Bending and spherical aberration of color in the short wavelength region on the telephoto side are reduced.

  The third lens unit L3 includes, in order from the object side, a positive lens 31 having a convex surface facing the object side, a positive lens 32 having a convex surface facing the object side, and a negative lens 33 having a concave surface facing the image side. 35, a biconvex positive lens 34. With this configuration, the positive refractive power of the third lens unit L3 is shared by three or more positive lenses, and various aberrations generated in the third lens unit, particularly spherical aberration, coma, The occurrence of axial chromatic aberration is reduced.

  The fourth lens unit L4 of Examples 1 to 5 includes one negative lens 41. By using a single lens, it is possible to perform rapid focusing when focusing with the fourth lens group.

  The fourth lens unit L4 according to the sixth exemplary embodiment includes one positive lens 41. By using a single lens, it is possible to perform rapid focusing when focusing with the fourth lens group.

  The fifth lens unit L5 of Examples 1 to 5 includes a positive lens 51 and a negative lens 52 in order from the object side. By comprising two positive and negative lenses, the occurrence of lateral chromatic aberration is reduced over the entire zoom range.

  In each embodiment, camera shake correction can be performed by moving an arbitrary lens group in a direction perpendicular to the optical axis.

  Next, numerical examples of the respective embodiments of the present invention will be shown. In each numerical example, i indicates the order of the surfaces from the object side, Ri is the radius of curvature of the lens surface, Di is the lens thickness and air space between the i-th surface and the i + 1-th surface, and Ndi and νdi are The refractive index and Abbe number for d line are shown. The two surfaces closest to the image side are filter members such as a crystal low-pass filter and an infrared cut filter.

  The meanings of symbols used in each numerical example are as follows. In the numerical examples, Ri is the radius of curvature of the i-th lens surface in order from the object side, Di is the i-th lens thickness and air spacing in order from the object side, and Ni and νi are the i-th lens in order from the object side. The refractive index and the Abbe number of the glass with respect to the d-line. Table 1 shows the relationship between the above-described conditional expressions and numerical examples.

  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 conic constant, and A4, A6, and A8 are the aspheric coefficients. When

It is expressed by the following formula. [E + X] means [× 10 + x], and [e−X] means [× 10−x].

  An aspherical surface is indicated by adding * after the surface number.

[Numerical Example 1]
Unit mm

Surface data surface number rd nd vd
1 97.951 1.40 1.85478 24.8
2 61.592 5.70 1.53775 74.7
3 -2285.817 0.50
4 58.986 4.40 1.59282 68.6
5 251.393 (variable)
6 447.003 0.90 1.72916 54.7
7 18.892 3.09
8 -279.492 0.80 1.55332 71.7
9 28.963 3.65
10 * -18.505 0.80 1.69680 55.5
11 * -53.337 0.17
12 53.525 1.60 1.95906 17.5
13 748.577 (variable)
14 (Aperture) ∞ (Variable)
15 * 17.079 5.00 1.55332 71.7
16 * 1083.651 0.50
17 17.186 3.80 1.59282 68.6
18 28.516 1.20 1.85478 24.8
19 13.210 3.00
20 * 22.372 3.30 1.61881 63.9
21 * -49.804 (variable)
22 * -80.982 1.31 1.61881 63.9
23 * 34.591 (variable)
24 * 35.448 5.00 1.62263 58.2
25 * -30.710 0.15
26 -71.585 0.90 1.80809 22.8
27 749.486 (variable)
28 ∞ 1.50 1.48749 70.2
29 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -1.18698e-005 A 6 = 2.45459e-007 A 8 = -9.91207e-010

11th page
K = 0.00000e + 000 A 4 = 4.14596e-008 A 6 = 2.35342e-007 A 8 = -8.81437e-010

15th page
K = -3.51356e-002 A 4 = -1.30996e-005 A 6 = -1.29163e-007 A 8 = 2.45824e-010

16th page
K = -6.71333e + 003 A 4 = 1.32107e-005 A 6 = -1.64420e-007 A 8 = 4.94942e-010

20th page
K = 1.83562e + 000 A 4 = -1.21088e-005 A 6 = -2.17210e-007 A 8 = 2.35505e-009

21st page
K = -1.15322e + 001 A 4 = 2.77417e-005 A 6 = -7.31070e-008 A 8 = 3.08082e-009

22nd page
K = 7.97629e + 001 A 4 = 2.39052e-004 A 6 = -1.69187e-006 A 8 = 1.02934e-008

23rd page
K = 1.68614e + 000 A 4 = 2.38798e-004 A 6 = -1.10583e-006 A 8 = 6.02308e-009

24th page
K = 0.00000e + 000 A 4 = -7.53270e-006 A 6 = 6.27479e-007 A 8 = -1.01813e-009

25th page
K = 0.00000e + 000 A 4 = 2.90055e-006 A 6 = 4.35069e-007 A 8 = -1.65396e-009

Various data Zoom ratio 11.81

Focal length 9.10 47.95 107.50
F number 2.88 2.88 2.88
Angle of view 34.27 9.34 4.20
Image height 6.20 7.89 7.89
Total lens length 111.76 127.95 136.56
BF 1.01 1.01 1.01

d 5 1.20 37.93 51.76
d13 29.00 2.03 1.89
d14 13.86 10.18 2.00
d21 2.25 14.01 13.57
d23 6.76 10.15 14.59
d27 9.00 3.98 3.07
d29 1.01 1.01 1.01

Zoom lens group data group Start surface Focal length
1 1 87.29
2 6 -14.32
3 15 20.79
4 22 -39.00
5 24 39.80


[Numerical example 2]
Unit mm

Surface data surface number rd nd vd
1 95.172 1.40 1.85478 24.8
2 61.371 5.70 1.53775 74.7
3 -30938.631 0.50
4 61.110 4.40 1.59282 68.6
5 240.237 (variable)
6 202.989 0.90 1.72916 54.7
7 16.769 3.85
8 -67.534 0.80 1.55332 71.7
9 42.924 3.42
10 * -16.945 0.80 1.55332 71.7
11 * -42.153 0.17
12 61.768 1.60 1.95906 17.5
13 748.577 (variable)
14 (Aperture) ∞ (Variable)
15 * 16.723 5.00 1.55332 71.7
16 * 1904.173 0.50
17 17.690 3.80 1.59282 68.6
18 28.012 1.20 1.85478 24.8
19 13.128 3.00
20 * 22.716 3.30 1.61881 63.9
21 * -55.065 (variable)
22 * -81.504 1.31 1.61881 63.9
23 * 34.496 (variable)
24 * 35.762 5.00 1.62263 58.2
25 * -30.736 0.15
26 -69.062 0.90 1.80809 22.8
27 -34057.238 (variable)
28 ∞ 1.50 1.48749 70.2
29 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -1.95940e-005 A 6 = 1.10974e-007 A 8 = -4.10487e-011

11th page
K = 0.00000e + 000 A 4 = -9.61703e-006 A 6 = 1.52418e-007 A 8 = -8.47747e-011

15th page
K = -3.89399e-002 A 4 = -1.49999e-005 A 6 = -1.29031e-007 A 8 = 4.41196e-010

16th page
K = -2.36413e + 004 A 4 = 1.13878e-005 A 6 = -1.67725e-007 A 8 = 8.37720e-010

20th page
K = 1.76399e + 000 A 4 = -9.05466e-006 A 6 = -1.72536e-007 A 8 = 1.97293e-009

21st page
K = -1.09481e + 001 A 4 = 3.04102e-005 A 6 = -2.51025e-008 A 8 = 2.34302e-009

22nd page
K = 7.72881e + 001 A 4 = 2.23103e-004 A 6 = -1.53039e-006 A 8 = 6.80309e-009

23rd page
K = -4.69151e-001 A 4 = 2.25407e-004 A 6 = -9.86519e-007 A 8 = 2.16444e-009

24th page
K = 0.00000e + 000 A 4 = -1.69965e-005 A 6 = 3.75989e-007 A 8 = -5.23077e-010

25th page
K = 0.00000e + 000 A 4 = -5.02682e-006 A 6 = 6.74979e-008 A 8 = 2.38833e-010

Various data Zoom ratio 12.64
Wide angle Medium Telephoto focal length 9.10 50.79 115.00
F number 2.88 3.00 3.00
Angle of view 34.27 8.83 3.92
Image height 6.20 7.89 7.89
Total lens length 112.92 132.55 142.17
BF 1.00 1.00 1.00

d 5 1.20 40.28 54.40
d13 28.99 3.15 1.89
d14 14.08 8.83 2.00
d21 2.78 15.37 15.33
d23 6.40 10.44 15.36
d27 9.26 4.27 2.99
d29 1.00 1.00 1.00

Zoom lens group data group Start surface Focal length
1 1 90.70
2 6 -14.27
3 15 21.26
4 22 -39.00
5 24 39.07


[Numerical Example 3]
Unit mm

Surface data surface number rd nd vd
1 97.129 1.40 2.00069 25.5
2 64.431 5.70 1.53775 74.7
3 -2529.364 0.50
4 60.935 4.40 1.59282 68.6
5 261.371 (variable)
6 190.335 0.90 1.72916 64.0
7 16.678 3.67
8 -73.195 0.80 1.55332 71.7
9 40.912 3.46
10 * -16.886 0.80 1.55332 71.7
11 * -41.789 0.17
12 62.864 1.60 1.95906 17.5
13 748.577 (variable)
14 (Aperture) ∞ (Variable)
15 * 16.849 5.00 1.55332 71.7
16 * -1053.741 0.50
17 16.814 3.80 1.49700 81.5
18 27.100 1.20 1.85478 24.8
19 13.277 3.00
20 * 21.776 3.30 1.59201 67.0
21 * -51.793 (variable)
22 * -82.477 1.31 1.62263 58.2
23 * 34.625 (variable)
24 * 44.709 5.00 1.62263 58.2
25 * -34.412 0.15
26 -112.612 0.90 1.80518 25.4
27 -1952.359 (variable)
28 ∞ 1.50 1.48749 70.2
29 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -5.09858e-005 A 6 = 4.80930e-007 A 8 = -2.18466e-009

11th page
K = 0.00000e + 000 A 4 = -3.82608e-005 A 6 = 5.37359e-007 A 8 = -2.35012e-009

15th page
K = -1.39687e-001 A 4 = -1.45766e-005 A 6 = -1.24264e-007 A 8 = 6.44146e-010

16th page
K = -1.60431e + 004 A 4 = 7.38481e-006 A 6 = -1.83260e-007 A 8 = 1.11516e-009

20th page
K = 1.51088e + 000 A 4 = -1.02221e-006 A 6 = -3.09103e-007 A 8 = 2.05882e-009

21st page
K = -8.48382e + 000 A 4 = 4.32813e-005 A 6 = -1.50150e-007 A 8 = 2.27648e-009

22nd page
K = 7.13821e + 001 A 4 = 2.31416e-004 A 6 = -1.56293e-006 A 8 = 7.33062e-009

23rd page
K = 1.03097e + 000 A 4 = 2.31346e-004 A 6 = -9.31031e-007 A 8 = 4.05836e-009

24th page
K = 0.00000e + 000 A 4 = -2.80208e-005 A 6 = 6.91767e-007 A 8 = -3.32504e-009

25th page
K = 0.00000e + 000 A 4 = -1.65840e-005 A 6 = 3.37024e-007 A 8 = -2.74555e-009

Various data Zoom ratio 13.19
Wide angle Medium telephoto focal length 9.10 53.80 120.00
F number 2.88 3.00 3.50
Angle of view 34.27 8.34 3.76
Image height 6.20 7.89 7.89
Total lens length 112.28 135.45 144.41
BF 1.00 1.00 1.00

d 5 1.20 43.55 57.34
d13 28.77 3.48 1.89
d14 13.93 8.44 2.00
d21 3.04 14.54 14.12
d23 6.28 11.36 16.01
d27 9.00 4.01 2.99
d29 1.00 1.00 1.00

Zoom lens group data group Start surface Focal length
1 1 92.89
2 6 -14.22
3 15 21.10
4 22 -39.00
5 24 40.29


[Numerical Example 4]
Unit mm

Surface data surface number rd nd vd
1 91.749 1.40 2.00069 25.5
2 61.489 5.70 1.53775 74.7
3 2578.023 0.50
4 63.187 4.40 1.59282 68.6
5 306.149 (variable)
6 155.616 0.90 1.72916 68.0
7 15.690 4.56
8 -33.472 0.80 1.49700 81.5
9 121.521 2.81
10 * -17.621 0.80 1.49700 81.5
11 * -46.593 0.17
12 79.154 1.60 2.10205 16.8
13 748.577 (variable)
14 (Aperture) ∞ (Variable)
15 * 16.711 5.00 1.55332 71.7
16 * -225.666 0.50
17 16.748 3.80 1.49700 81.5
18 25.786 1.20 1.85478 24.8
19 12.825 3.00
20 * 21.947 3.30 1.59201 67.0
21 * -65.678 (variable)
22 * -71.318 1.31 1.62263 58.2
23 * 37.078 (variable)
24 * 40.546 5.00 1.62263 58.2
25 * -34.382 0.15
26 -64.820 0.90 1.80518 25.4
27 -123.084 (variable)
28 ∞ 1.50 1.48749 70.2
29 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -3.63412e-005 A 6 = 1.69083e-007 A 8 = 4.13746e-012

11th page
K = 0.00000e + 000 A 4 = -2.91538e-005 A 6 = 2.39419e-007 A 8 = -2.51096e-010

15th page
K = 7.86705e-002 A 4 = -1.84850e-005 A 6 = -1.19843e-007 A 8 = 1.38907e-010

16th page
K = -5.33738e + 002 A 4 = 1.02313e-005 A 6 = -1.84726e-007 A 8 = 7.90810e-010

20th page
K = 6.90829e-001 A 4 = 2.39218e-005 A 6 = -2.73743e-007 A 8 = 1.56823e-009

21st page
K = -6.73995e + 000 A 4 = 5.50644e-005 A 6 = -1.02355e-007 A 8 = 1.37322e-009

22nd page
K = 5.48958e + 001 A 4 = 2.23624e-004 A 6 = -1.31730e-006 A 8 = 1.76060e-009

23rd page
K = 2.89917e-001 A 4 = 2.19267e-004 A 6 = -6.40083e-007 A 8 = -5.32807e-009

24th page
K = 0.00000e + 000 A 4 = -2.02395e-005 A 6 = 4.21169e-007 A 8 = 1.71228e-009

25th page
K = 0.00000e + 000 A 4 = -1.24532e-005 A 6 = 4.74019e-008 A 8 = 4.02476e-009

Various data Zoom ratio 13.74
Wide angle Medium Tele focal length 9.10 50.20 125.00
F number 2.88 3.50 4.00
Angle of view 34.27 8.93 3.61
Image height 6.20 7.89 7.89
Total lens length 112.75 136.03 147.11
BF 1.00 1.00 1.00

d 5 1.20 41.99 58.18
d13 28.98 4.69 1.89
d14 13.60 8.39 2.00
d21 1.94 14.40 15.14
d23 6.68 11.96 16.62
d27 10.04 4.29 2.97
d29 1.00 1.00 1.00

Zoom lens group data group Start surface Focal length
1 1 94.52
2 6 -14.28
3 15 21.29
4 22 -39.00
5 24 37.08


[Numerical Example 5]
Unit mm

Surface data surface number rd nd vd
1 88.847 1.40 2.00069 25.5
2 60.759 5.70 1.53775 74.7
3 1064.834 0.50
4 64.876 4.40 1.59282 68.6
5 282.888 (variable)
6 189.488 0.90 1.72916 70.0
7 14.962 5.22
8 -27.815 0.80 1.43875 94.9
9 464.502 2.59
10 * -20.541 0.80 1.43875 94.9
11 * -74.667 0.17
12 85.908 1.60 2.10205 16.8
13 748.577 (variable)
14 (Aperture) ∞ (Variable)
15 * 16.769 5.00 1.55332 71.7
16 * -259.351 0.50
17 16.877 3.80 1.49700 81.5
18 26.084 1.20 1.85478 24.8
19 12.989 3.00
20 * 21.999 3.30 1.59201 67.0
21 * -68.840 (variable)
22 * -59.852 1.31 1.62263 58.2
23 * 41.203 (variable)
24 * 38.063 5.00 1.62263 58.2
25 * -33.527 0.15
26 -56.757 0.90 1.80518 25.4
27 -106.537 (variable)
28 ∞ 1.50 1.48749 70.2
29 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -8.93602e-005 A 6 = 9.66023e-007 A 8 = -9.29084e-009

11th page
K = 0.00000e + 000 A 4 = -8.49546e-005 A 6 = 1.01486e-006 A 8 = -8.24865e-009

15th page
K = 1.20576e-001 A 4 = -1.95899e-005 A 6 = -6.36481e-008 A 8 = 6.36857e-010

16th page
K = -6.03568e + 002 A 4 = 8.20967e-006 A 6 = -8.21368e-008 A 8 = 1.30004e-009

20th page
K = 7.29996e-001 A 4 = 1.14766e-005 A 6 = -1.98352e-007 A 8 = 1.97528e-009

21st page
K = -2.04654e + 001 A 4 = 4.12681e-005 A 6 = -6.71293e-008 A 8 = 2.04500e-009

22nd page
K = 4.52232e + 001 A 4 = 2.13137e-004 A 6 = -1.45940e-006 A 8 = 7.13566e-009

23rd page
K = -2.24344e + 000 A 4 = 2.03415e-004 A 6 = -1.11315e-006 A 8 = 2.51129e-010

24th page
K = 0.00000e + 000 A 4 = 1.90568e-006 A 6 = 1.91865e-007 A 8 = 1.58924e-009

25th page
K = 0.00000e + 000 A 4 = 1.65797e-005 A 6 = -1.13900e-007 A 8 = 3.17191e-009

Various data Zoom ratio 14.42
Wide angle Medium Telephoto focal length 9.01 47.89 130.00
F number 2.80 4.00 5.60
Angle of view 34.52 9.36 3.47
Image height 6.20 7.89 7.89
Total lens length 113.60 140.52 151.81
BF 1.00 1.00 1.00

d 5 1.20 44.92 62.98
d13 29.00 5.73 1.89
d14 13.38 8.58 1.99
d21 1.87 13.30 14.26
d23 7.13 11.96 15.86
d27 10.27 5.29 4.09
d29 1.00 1.00 1.00

Zoom lens group data group Start surface Focal length
1 1 98.44
2 6 -14.22
3 15 21.47
4 22 -39.00
5 24 36.16


[Numerical Example 6]
Unit mm

Surface data surface number rd nd vd
1 146.951 1.20 1.85478 24.8
2 74.247 4.80 1.59522 67.7
3 -620.072 0.59
4 53.627 3.50 1.60311 60.6
5 169.449 (variable)
6 -7270.894 1.04 1.72916 58.2
7 16.584 2.55
8 100.958 0.93 1.55332 71.7
9 23.390 3.54
10 * -24.102 0.93 1.59282 68.6
11 * -90.356 0.20
12 67.809 1.86 2.10205 16.8
13 868.349 (variable)
14 (Aperture) ∞ (Variable)
15 * 18.138 5.80 1.55332 71.7
16 * -386.305 0.59
17 22.656 4.41 1.49700 81.5
18 40.030 1.39 1.85478 24.8
19 15.811 3.48
20 * 28.331 3.83 1.59282 68.6
21 * -58.310 (variable)
22 123.796 3.00 1.59282 68.6
23 * -120.048 (variable)
24 ∞ 1.50 1.51633 64.1
25 ∞ (variable)
Image plane ∞

Aspheric data 10th surface
K = 0.00000e + 000 A 4 = -2.83945e-004 A 6 = 1.61447e-006 A 8 = 9.80609e-010

11th page
K = 0.00000e + 000 A 4 = -2.62516e-004 A 6 = 2.15045e-006 A 8 = -3.20770e-009

15th page
K = 5.78925e-001 A 4 = -2.72589e-005 A 6 = -1.22980e-007 A 8 = -6.84194e-010

16th page
K = 2.15531e + 002 A 4 = 1.07879e-005 A 6 = -1.85649e-007 A 8 = 2.49618e-010

20th page
K = 2.05414e + 000 A 4 = -4.27490e-006 A 6 = -1.48953e-007 A 8 = -1.12446e-009

21st page
K = -2.34619e + 001 A 4 = 4.38736e-006 A 6 = 7.20270e-008 A 8 = -1.68803e-009

23rd page
K = 0.00000e + 000 A 4 = 8.99440e-007 A 6 = -2.86521e-008

Various data Zoom ratio 11.05
Wide angle Medium Tele focal length 9.97 24.00 110.15
F number 2.88 4.00 5.60
Angle of view 31.88 18.01 4.05
Image height 6.20 7.80 7.80
Total lens length 112.86 121.12 150.95
BF 1.00 1.00 1.00

d 5 2.23 19.98 54.62
d13 19.31 3.36 2.10
d14 22.37 17.19 2.00
d21 13.41 24.12 39.26
d23 9.43 10.36 6.86
d25 1.00 1.00 1.00

Zoom lens group data group Start surface Focal length
1 1 91.03
2 6 -14.80
3 14 ∞
4 15 25.87
5 22 103.28

Table 1 shows the relationship between the above-described conditional expressions and various numerical values in the numerical examples.

  Next, an embodiment of a digital camera (optical apparatus) using the zoom lens of the present invention as a photographing optical system will be described with reference to FIG. In FIG. 25, reference numeral 60 denotes a digital camera body, 61 denotes a photographing optical system constituted by the zoom lens of the above-described embodiment, 62 denotes an imaging element such as a CCD that receives a subject image by the photographing optical system 61, and 63 denotes an imaging element 62. A recording means 64 for recording the received subject image, and a viewfinder 64 for observing the subject image displayed on a display element (not shown). The display element is constituted by a liquid crystal panel or the like, and a subject image formed on the image sensor 62 is displayed. Reference numeral 65 denotes a liquid crystal display panel having a function equivalent to that of the finder. Thus, by applying the zoom lens of the present invention to an optical apparatus such as a digital camera, an optical apparatus having a small size and high optical performance is realized.

Li i-th lens group, SP aperture stop

Claims (15)

A rear group including a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and at least one lens group in order from the object side to the image side. Comprising
In zoom lenses in which at least the first to third lens units move during zooming from the wide-angle end to the telephoto end,
The second lens group has at least three negative lenses and one or more positive lenses,
The focal length of the second lens is f2, the focal length ft at the telephoto end, the average Abbe number of the negative lens included in the second lens group is v2nave, and the average Abbe number of the positive lens included in the second lens group is v2pave. A zoom lens that satisfies the following formula:
0.050 <| f2 | / ft <0.140
40.0 <v2nave−v2pave <100.0 2. The zoom lens according to claim 1, wherein when the lateral magnification of the second lens group at the wide-angle end is β2w and the lateral magnification at the telephoto end is β2t, the following expression is satisfied.
4.0 <β2t / β2w <10.0 3. The zoom according to claim 1, wherein when the average focal length of the negative lens included in the second lens group is f2nave and the focal length at the wide-angle end is fw, the following expression is satisfied. lens.
3.00 <| f2nave | / fw <10.00 4. The zoom lens according to claim 1, wherein the following expression is satisfied when an average refractive index of a negative lens included in the second lens group is N2nave. 5.
1.500 <N2nave <1.800   The second lens group includes 21 lenses having a negative refractive power, 22 lenses having a negative refractive power, and 23 lenses having a negative refractive power in order from the object side. The zoom lens according to any one of claims 1 to 4. 6. The zoom lens according to claim 5, wherein when the radius of curvature of the object side surface of the 21 lens of the second lens group is R21o and the radius of curvature of the image side surface is R21i, the following expression is satisfied.
0.90 <(R21o + R21i) / (R21o−R21i) <2.00 The zoom according to claim 5 or 6, wherein when the radius of curvature of the object side surface of the 22 lenses of the second lens group is R22o and the radius of curvature of the image side surface is R22i, the following expression is satisfied. lens.
−1.00 <(R22o + R22i) / (R22o−R22i) <2.00 The following expression is satisfied, where R23o is the radius of curvature of the object side surface of the 23 lenses of the second lens group, and R23i is the radius of curvature of the image side surface. The zoom lens according to item.
−3.00 <(R23o + R23i) / (R23o−R23i) <− 1.00 9. The zoom lens according to claim 1, wherein the following expression is satisfied when a focal length of the one lens group is f <b> 1.
0.500 <f1 / ft <1.000 The first lens group includes at least one positive lens and a negative lens. The average Abbe number of positive lenses included in the first lens group is v1pave, and the average Abbe number of negative lenses is v1nave. The zoom lens according to claim 1, wherein the following expression is satisfied.
40.0 <v1pave−v1nave <80.0 11. The zoom lens according to claim 1, wherein the following expression is satisfied when a focal length of the three lens groups is f <b> 3.
0.100 <f3 / ft <0.250 The third lens group includes at least one positive lens and a negative lens. The average Abbe number of positive lenses included in the third lens group is v3pave, and the average Abbe number of negative lenses is v3nave. The zoom lens according to any one of claims 1 to 11, wherein the following expression is satisfied.
40.0 <v3pave−v3nave <80.0   The zoom lens according to any one of claims 1 to 12, wherein the rear group includes a fourth lens group having a negative refractive power closest to the object side.   The zoom lens according to any one of claims 1 to 12, wherein the rear group includes a fourth lens group having a positive refractive power closest to the object side.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.