JP2017068116A - Zoom lens, optical device, and method for manufacturing the zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens having good optical performance even with a high variable magnification, an optical device, and a method for manufacturing the zoom lens.SOLUTION: A zoom lens includes a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power that are arranged in this order from an object side along an optical axis. The fourth lens group G4 has a plastic negative lens. When ft represents a focal length of an entire system in a telephoto end state, f1 represents a focal length of the first lens group G1, f4 represents a focal length of the fourth lens group G4, β4 represents a magnification ratio of the fourth lens group G4 in the telephoto end state, and β5 represents a synthetic magnification ratio of the lens group arranged closer to an image side than the fourth lens group G4 in the telephoto end state, the zoom lens satisfies the following conditional expression (1): 0.020<{β5(1-β4)f1 (-f4)}/ft<0.035...(1).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens, an optical apparatus, and a method for manufacturing a zoom lens.

  Conventionally, as a zoom lens having a high zoom ratio, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power. There has been proposed a zoom lens that includes a lens group, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, and performs zooming by moving each lens group (for example, a patent) Reference 1).

  The conventional technique has a problem that sufficient optical performance cannot be obtained.

JP2011-75985A

  The zoom lens according to the present invention has a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power, which are arranged in order from the object side along the optical axis. A third lens group, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, the fourth lens group having a plastic negative lens, and Satisfies the equation.

0.020 <{β5 ² (1-β4) ² · f1 · (−f4)} / ft ² <0.035
However,
ft: focal length of the entire system in the telephoto end state,
f1: the focal length of the first lens group,
f4: focal length of the fourth lens group,
β4: magnification of the fourth lens group in the telephoto end state,
β5: A composite magnification of the lens group disposed on the image side of the fourth lens group in the telephoto end state.

  An optical apparatus according to the present invention is equipped with the zoom lens described above.

  The zoom lens manufacturing method according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refraction arranged in order from the object side along the optical axis. A zoom lens having a third lens group having a power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, wherein the fourth lens group includes: Each lens is arranged in a lens barrel so as to have a plastic negative lens and satisfy the following conditional expression.

0.020 <{β5 ² (1-β4) ² · f1 · (−f4)} / ft ² <0.035
However,
ft: focal length of the entire system in the telephoto end state,
f1: the focal length of the first lens group,
f4: focal length of the fourth lens group,
β4: magnification of the fourth lens group in the telephoto end state,
β5: A composite magnification of the lens group disposed on the image side of the fourth lens group in the telephoto end state.

It is a figure which shows the structure of the zoom lens which concerns on 1st Example, and the movement locus | trajectory (arrow) of each group from a wide-angle end state (W) to a telephoto end state (T). FIG. 6 is a diagram illustrating various aberrations of the zoom lens according to Example 1 at an infinite shooting distance, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows a telephoto end state. It is a figure which shows the structure of the zoom lens which concerns on 2nd Example, and the movement locus | trajectory (arrow) of each group from a wide-angle end state (W) to a telephoto end state (T). FIG. 6 is a diagram illustrating various aberrations of the zoom lens according to Example 2 at an imaging distance of infinity, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows a telephoto end state. It is a figure which shows the structure of the zoom lens concerning 3rd Example, and the movement locus | trajectory (arrow) of each group from a wide-angle end state (W) to a telephoto end state (T). FIG. 6 is a diagram illustrating various aberrations of the zoom lens according to Example 3 at an infinite shooting distance, where (a) shows a wide-angle end state, (b) shows an intermediate focal length state, and (c) shows a telephoto end state. It is a figure which shows the structure of the camera carrying the zoom lens which concerns on this embodiment. It is a figure which shows the outline of the manufacturing method of the zoom lens which concerns on this embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. As shown in FIG. 1, the zoom lens ZL according to the present embodiment includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power, which are arranged in order from the object side along the optical axis. A fourth lens group having a lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power; The group G4 has a plastic negative lens (lens L41 in FIG. 1).

  In the present embodiment, either a glass lens or a plastic lens may be used as a lens constituting the zoom lens ZL (except for a lens specified as a plastic lens).

  By having a plurality of lens groups as in the above configuration, an optical system with a high zoom ratio can be easily configured. Moreover, cost reduction can be achieved by using a plastic lens. However, the higher the magnification, the greater the change in optical performance (for example, focal length and aberration fluctuation) due to temperature change. Therefore, in the present embodiment, the negative lens of the fourth lens group G4 is made plastic, and the following conditional expression (1) is satisfied, so that the focal length and aberration fluctuation at the time of temperature change are alleviated, and higher optical performance is achieved. I try to get it.

0.020 <{β5 ² (1-β4) ² · f1 · (−f4)} / ft ² <0.035 (1)
However,
ft: focal length of the entire system in the telephoto end state,
f1: Focal length of the first lens group G1
f4: focal length of the fourth lens group G4,
β4: magnification of the fourth lens group G4 in the telephoto end state,
β5: A composite magnification of the lens unit disposed on the image side of the fourth lens unit G4 in the telephoto end state.

  If the upper limit of conditional expression (1) is exceeded, it will be difficult to correct various aberrations such as spherical aberration and astigmatism when the temperature changes.

  In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 0.032. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 0.029.

  If the lower limit of conditional expression (1) is not reached, it will be difficult to correct various aberrations such as spherical aberration and astigmatism when the temperature changes.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 0.021.

  In the zoom lens ZL according to the present embodiment, it is preferable that the distance between the lens groups changes during zooming from the wide-angle end state to the telephoto end state. By satisfying this configuration, it is possible to achieve a high zoom ratio while maintaining good optical performance.

  In the zoom lens ZL according to the present embodiment, it is preferable that the first lens group G1 to the fourth lens group G4 move during zooming from the wide-angle end state to the telephoto end state. By satisfying this configuration, it is possible to achieve a high zoom ratio while maintaining good optical performance.

  In the zoom lens ZL according to the present embodiment, it is preferable that the first lens group G1 to the fifth lens group G5 move during zooming from the wide-angle end state to the telephoto end state. By satisfying this configuration, it is possible to achieve a high zoom ratio while maintaining good optical performance.

  In the zoom lens ZL according to the present embodiment, it is preferable that the first lens group G1 has a positive lens and satisfies the following conditional expression (2).

65.0 <νdp1 <100.0 (2)
However,
νdp1: Average value of the Abbe number of the positive lens included in the first lens group G1.

  Conditional expression (2) defines an appropriate Abbe number of the positive lens included in the first lens group G1.

  Exceeding the upper limit value of conditional expression (2) is not preferable because longitudinal chromatic aberration and lateral chromatic aberration are deteriorated and performance change at the time of temperature change is increased.

  In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 92.1. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 84.3.

  If the lower limit of conditional expression (2) is not reached, the longitudinal chromatic aberration and the lateral chromatic aberration are deteriorated, and the performance change at the time of temperature change is also increased.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 67.8. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 70.7.

  In the zoom lens ZL according to the present embodiment, it is preferable that the first lens group G1 has a negative lens and satisfies the following conditional expression (3).

23.0 <νdn1 <38.0 (3)
However,
νdp1: Average value of the Abbe number of the negative lens included in the first lens group G1.

  Conditional expression (3) defines an appropriate Abbe number of the negative lens included in the first lens group G1.

  If the upper limit of conditional expression (3) is exceeded, axial chromatic aberration and lateral chromatic aberration will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 36.1. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 34.2.

  If the lower limit value of conditional expression (3) is not reached, axial chromatic aberration and lateral chromatic aberration will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 25.8. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 28.5.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (4).

5.0 <β2t / β2w <13.0 (4)
However,
β2w: magnification of the second lens group G2 in the wide-angle end state,
β2t: magnification of the second lens group G2 in the telephoto end state.

  Conditional expression (4) defines an appropriate ratio between the magnification of the second lens group G2 in the wide-angle end state and the magnification of the second lens group G2 in the telephoto end state.

  If the upper limit of conditional expression (4) is exceeded, various aberrations such as coma will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 11.8. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 10.6.

  Below the lower limit of conditional expression (4), it becomes difficult to correct various aberrations such as coma and astigmatism.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 6.0. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 7.1.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (5).

1.50 <(r41 + r42) / (r41−r42) <3.50 (5)
However,
r41: radius of curvature of the surface closest to the object side of the fourth lens group G4,
r42: radius of curvature of the most image-side surface of the fourth lens group G4.

  Conditional expression (5) defines a preferable shape when the fourth lens group G4 is regarded as one lens.

  If the upper limit value of conditional expression (5) is exceeded, various aberrations such as spherical aberration and field curvature at a short distance deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (5) to 3.37. In order to secure the effect of the present embodiment, it is preferable to set the upper limit value of conditional expression (5) to 3.24.

  If the lower limit value of conditional expression (5) is not reached, various aberrations such as spherical aberration and field curvature at a short distance will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (5) to 1.65. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (5) to 1.80.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (6).

  1.00 <f1 / (− f4) <4.00 (6)

  Conditional expression (6) defines an appropriate ratio between the focal length of the first lens group G1 and the focal length of the fourth lens group G4.

  If the upper limit of conditional expression (6) is exceeded, various aberrations such as lateral chromatic aberration and curvature of field deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (6) to 3.25. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (6) to 2.51.

  If the lower limit of conditional expression (6) is not reached, various aberrations such as lateral chromatic aberration and curvature of field deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (6) to 1.13. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (6) to 1.25.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (7).

  1.50 <β4 <2.00 (7)

  Conditional expression (7) defines an appropriate magnification of the fourth lens group G4.

  If the upper limit value of conditional expression (7) is exceeded, various aberrations such as axial chromatic aberration and lateral chromatic aberration will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (7) to 1.90. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (7) to 1.79.

  If the lower limit value of conditional expression (7) is not reached, various aberrations such as longitudinal chromatic aberration and lateral chromatic aberration are deteriorated.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (7) to 1.54. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (7) to 1.59.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (8).

  2.20 <ft / f1 <2.90 (8)

  Conditional expression (8) defines an appropriate ratio between the focal length of the entire system in the telephoto end state and the focal length of the first lens group G1.

  If the upper limit of conditional expression (8) is exceeded, various aberrations such as lateral chromatic aberration and curvature of field deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (8) to 2.86. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (8) to 2.82.

  If the lower limit of conditional expression (8) is not reached, various aberrations such as lateral chromatic aberration and curvature of field deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (8) to 2.35. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (8) to 2.49.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (9).

1.50 <f3 / (− f2) <2.00 (9)
However,
f2: focal length of the second lens group G2,
f3: focal length of the third lens group G3.

  Conditional expression (9) defines an appropriate ratio between the focal length of the second lens group G2 and the focal length of the third lens group G3.

  If the upper limit value of conditional expression (9) is exceeded, various aberrations such as longitudinal chromatic aberration and spherical aberration will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (9) to 1.95. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (9) to 1.89.

  If the lower limit value of conditional expression (9) is not reached, various aberrations such as axial chromatic aberration and spherical aberration are deteriorated.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (9) to 1.59. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (9) to 1.67.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (10).

22.0 <(β3t · β2t) / (β3w · β2w) <32.0 (10)
However,
β2w: magnification of the second lens group G2 in the wide-angle end state β2t: magnification of the second lens group G2 in the telephoto end state,
β3w: magnification of the third lens group G3 in the wide-angle end state,
β3t: magnification of the third lens group G3 in the telephoto end state.

  Conditional expression (10) defines an appropriate magnification change product of the second lens group G2 and the third lens group G3 during zooming.

  If the upper limit of conditional expression (10) is exceeded, various aberrations such as axial chromatic aberration, lateral chromatic aberration, and astigmatism will deteriorate.

  In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (10) to 31.0. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (10) to 30.1.

  If the lower limit value of conditional expression (10) is not reached, various aberrations such as longitudinal chromatic aberration, lateral chromatic aberration, and astigmatism are deteriorated.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (10) to 22.7. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (10) to 23.5.

  In the zoom lens ZL according to this embodiment, the fourth lens group G4 is preferably made of a plastic negative lens. By satisfying this configuration, the optical system can be reduced in size. Moreover, cost can be suppressed.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (11).

0.10 ° <ωt <10.00 ° (11)
However,
ωt: Half angle of view in the telephoto end state.

  Conditional expression (11) is a condition that defines an optimum value of the angle of view in the telephoto end state. By satisfying this conditional expression (11), coma aberration, distortion aberration, and field curvature can be favorably corrected.

  In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (11) to 8.00 °. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (11) to 6.00 °. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (11) to 4.00 °. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (11) to 2.00 °.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (11) to 0.30 °. In order to secure the effect of the present embodiment, it is preferable to set the lower limit value of conditional expression (11) to 0.50 °.

  The zoom lens ZL according to this embodiment preferably satisfies the following conditional expression (12).

20.00 ° <ωw <80.00 ° (12)
However,
ωw: Half angle of view in the wide angle end state.

  Conditional expression (12) is a condition that defines an optimum value of the angle of view in the wide-angle end state. By satisfying this conditional expression (12), coma aberration, distortion aberration, and field curvature can be favorably corrected while having a wide angle of view.

  In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (12) to 70.00 °. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (12) to 60.00 °. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (12) to 50.00 °.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (12) to 22.00 °. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (12) to 25.00 °. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (12) to 30.00 °. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (12) to 35.00 °.

  According to the zoom lens ZL according to the present embodiment having the above-described configuration, it is possible to realize a zoom lens having good optical performance while being highly variable.

Next, a camera (optical apparatus) including the above-described zoom lens ZL will be described with reference to FIG. As shown in FIG. 7, the camera 1 is an interchangeable lens camera (so-called mirrorless camera) provided with the zoom lens ZL described above as the photographing lens 2. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2, and on the imaging surface of the imaging unit 3 via an OLPF (Optical Low Pass Filter) not shown. A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4. When a release button (not shown) is pressed by the photographer, the subject image generated by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

  The zoom lens ZL according to the present embodiment mounted on the camera 1 as the photographic lens 2 has high optical performance and high optical performance due to its characteristic lens configuration as can be seen from each example described later. Have. Therefore, according to the present camera 1, it is possible to realize an optical apparatus having good optical performance while being highly variable.

  In this embodiment, an example of a mirrorless camera has been described, but the present invention is not limited to this. For example, even when the zoom lens ZL described above is mounted on a single-lens reflex camera that has a quick return mirror in the camera body and observes a subject with a finder optical system, the same effect as the camera 1 can be obtained. .

  Next, the method for manufacturing the zoom lens ZL described above will be outlined with reference to FIG. First, in the lens barrel, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive refractive power. The lenses are arranged so as to have a third lens group G3, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power (step ST10). The fourth lens group G4 arranges each lens in the lens barrel so as to have a plastic negative lens (step ST20). Each lens is arranged in the lens barrel so as to satisfy at least the conditional expression (1) among the conditional expressions (step ST30).

  As an example of the lens arrangement in this embodiment, as shown in FIG. 1, a meniscus negative lens L11 and a biconvex positive lens L12 having a concave surface facing the image side in order from the object side along the optical axis. And a meniscus positive lens L13 having a convex surface facing the object side to form a first lens group G1, a meniscus negative lens L21 having a concave surface facing the image side, and a biconcave lens A negative lens L22 and a biconvex positive lens L23 are arranged to form the second lens group G2, and a biconvex positive lens L31, a biconvex positive lens L32, and a biconcave negative lens L33. A cemented lens and a biconvex positive lens L34 are arranged to form a third lens group G3, and a meniscus plastic negative lens L41 having a concave surface facing the image side is arranged to form a fourth lens group G4. Convex to A positive lens L51 of digits meniscus shape, and the fifth lens group G5 are arranged and a negative lens L52 of a meniscus shape with a concave surface facing the image side. The zoom lens ZL is manufactured by arranging the lens groups thus prepared in the above-described procedure.

  According to the manufacturing method according to the present embodiment, it is possible to manufacture a zoom lens ZL having good optical performance while having a high zoom ratio.

  Each example according to the present embodiment will be described with reference to the drawings. 1, 3, and 5 are cross-sectional views illustrating the configuration and refractive power distribution of zoom lenses ZL (ZL1 to ZL3) according to the respective examples. In the lower part of the cross-sectional views of the zoom lenses ZL1 to ZL3, the moving direction along the optical axis of each lens group when zooming from the wide-angle end state (W) to the telephoto end state (T) is indicated by arrows.

  Each reference code for FIG. 1 according to the first embodiment is used independently for each embodiment in order to avoid complication of explanation due to an increase in the number of digits of the reference code. Therefore, even if the same reference numerals as those in the drawings according to the other embodiments are given, they are not necessarily in the same configuration as the other embodiments.

  Tables 1 to 3 are shown below, but these are tables of specifications in the first to third examples.

  All the lenses are made of glass except those specified as plastic.

  In each embodiment, d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm) are selected as the calculation targets of the aberration characteristics.

  In [Lens Specifications] in the table, the surface number is the order of the optical surfaces from the object side along the light traveling direction, R is the radius of curvature of each optical surface, D is the next optical surface from each optical surface ( Or nd is the refractive index of the material of the optical member with respect to the d-line, and νd is the Abbe number based on the d-line of the material of the optical member. Further, the object surface is the object surface, Di is the surface interval (surface interval between the i-th surface and the (i + 1) -th surface), the curvature radius “∞” is a plane or an aperture, (aperture S) is the aperture stop S, and the image plane Indicates the image plane I, respectively. The refractive index of air “1.0000” is omitted. When the optical surface is an aspherical surface, the surface number is marked with *, and the column of curvature radius R indicates the paraxial curvature radius.

  In [Overall specifications] in the table, f is the focal length of the entire lens system, φ is the aperture stop diameter, Fno is the F number, 2ω is the angle of view (unit: °), and BF is the final lens surface on the optical axis. From the lens front surface to the paraxial image plane, BF (air) is the distance from the last lens surface on the optical axis to the paraxial image plane expressed in terms of air, and TL is from the forefront of the lens on the optical axis. The distance to the paraxial image plane, TL (air), is obtained by adding BF (air) to the distance from the lens front surface to the lens final surface on the optical axis.

In [Aspherical data] in the table, the shape of the aspherical surface shown in [Lens specifications] is shown by the following equation (a). X (y) is the distance along the optical axis direction from the tangential plane at the apex of the aspheric surface to the position on the aspheric surface at height y, R is the radius of curvature of the reference sphere (paraxial radius of curvature), and κ is Ai represents the i-th aspherical coefficient. “E-n” indicates “× 10 ⁻ⁿ ”. For example, 1.234E-05 = 1.234 × 10 ⁻⁵ . The secondary aspheric coefficient A2 is 0, and the description is omitted.

X (y) = (y ² / R) / {1+ (1-κ × y ² / R ² ) ^1/2 } + A4 × y ⁴ + A6 × y ⁶
... (a)

  In [Variable interval data] in the table, the surface interval value Di in each state of the wide-angle end, the intermediate focal length, and the telephoto end is shown. Di represents the distance between the i-th surface and the (i + 1) -th surface.

  In [Lens Group Data] in the table, G is the group number, the first group surface is the surface number of the most object side of each group, the group focal length is the focal length of each group, and the lens configuration length is the most object side of each group. The distance on the optical axis from the lens surface to the lens surface closest to the image plane is shown.

  [Conditional expression] in the table indicates values corresponding to the conditional expressions (1) to (12).

  Hereinafter, in all the specification values, “mm” is generally used for the focal length f, curvature radius R, surface interval D, and other lengths, etc. unless otherwise specified, but the optical system is proportionally enlarged. Alternatively, the same optical performance can be obtained even by proportional reduction, and the present invention is not limited to this. Further, the unit is not limited to “mm”, and other appropriate units can be used.

  The description of the table so far is common to all the embodiments, and the description below is omitted.

(First embodiment)
A first embodiment will be described with reference to FIGS. 1 and 2 and Table 1. FIG. As shown in FIG. 1, the zoom lens ZL (ZL1) according to the first example includes a first lens group G1 having a positive refractive power arranged in order from the object side along the optical axis, and a negative refractive power. A second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The

  The first lens group G1 includes a cemented lens of a meniscus negative lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side. And a meniscus-shaped positive lens L13 facing the lens.

  The second lens group G2 is arranged in order from the object side along the optical axis, the meniscus negative lens L21 having a concave surface on the image side, a biconcave negative lens L22, and a biconvex positive lens L23. It consists of.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex positive lens L31, a cemented lens of a biconvex positive lens L32, and a biconcave negative lens L33, It is composed of a convex positive lens L34. The positive lens L31 has two aspheric surfaces.

  The fourth lens group G4 includes a meniscus plastic negative lens L41 having a concave surface directed toward the image side.

  The fifth lens group G5 is composed of a meniscus positive lens L51 having a convex surface facing the object side and a meniscus negative lens L52 having a concave surface facing the image side, which are arranged in order from the object side along the optical axis. Is done.

  An aperture stop S for adjusting the amount of light is disposed between the second lens group G2 and the third lens group G3.

  On the image side of the fifth lens group G5, a low-pass filter LPF for cutting a spatial frequency equal to or higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I, is disposed.

  In the zoom lens ZL1 according to the present embodiment, the first lens group G1, the second lens group G2, the aperture stop S, and the like so that the distance between the lens groups changes during zooming from the wide-angle end state to the telephoto end state. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 are moved.

  Table 1 below shows the values of each item in the first example. Surface numbers 1 to 27 in Table 1 correspond to the optical surfaces m1 to m27 shown in FIG.

(Table 1)
[Lens specifications]
Surface number R D nd νd
Object ∞
1 113.374 2.17 1.9037 31.3
2 69.405 7.60 1.4978 82.6
3 -2184.641 0.22
4 71.364 5.86 1.4875 70.3
5 647.012 (D5)
6 1087.437 1.52 1.8348 42.7
7 15.039 8.46
8 -33.637 1.30 1.8348 42.7
9 153.075 0.43
10 42.629 3.47 1.9460 18.0
11 -375.399 (D11)
12 ∞ 0.91 (Aperture S)
* 13 14.517 4.99 1.5920 67.1
* 14 -155.641 0.22
15 21.062 4.34 1.5168 63.9
16 -41.568 0.87 1.8830 40.7
17 12.453 1.74
18 27.029 3.26 1.5182 58.8
19 -40.191 (D19)
20 91.941 1.30 1.5311 55.9
21 29.519 (D21)
22 23.334 3.91 1.4875 70.3
23 555.193 0.43
24 112.042 1.09 1.9020 25.3
25 59.119 (D25)
26 ∞ 1.99 1.5168 63.9
27 ∞ (BF)
Image plane ∞

[Overall specifications]
Zoom ratio 33.14
Wide-angle end Intermediate focus Telephoto end f 10.0 53.2 331.4
φ 15.6 15.6 15.6
Fno 3.1 4.7 6.7
2ω 84.0 18.6 3.0
BF 2.07 2.07 2.07
BF (Air) 11.60 28.24 10.55
TL 156.79 179.84 216.36
TL (Air) 156.11 179.16 215.68

[Aspherical data]
Surface number κ A4 A6
13 0.7008 -8.09E-06 0.00E + 00
14 1.0000 1.76E-06 0.00E + 00

[Variable interval data]
Variable interval Wide-angle end Intermediate focus Telephoto end
D5 1.77 46.47 83.48
D11 70.17 22.33 1.55
D19 7.13 18.15 27.06
D21 11.36 9.89 38.96
D25 8.22 24.86 7.17

[Lens group data]
Group number Group first surface Group focal length Lens construction length G1 1 119.4 15.84
G2 6 -16.6 15.19
G3 13 30.6 15.41
G4 20 -82.5 1.30
G5 22 73.8 5.43

[Conditional expression]
Conditional expression (1) {β5 ² (1-β4) ² · f1 · (−f4)} / ft ² = 0.026
Conditional expression (2) νdp1 = 76.4
Conditional expression (3) νdn1 = 31.3
Conditional expression (4) β2t / β2w = 8.1
Conditional expression (5) (r41 + r42) / (r41-r42) = 1.95
Conditional expression (6) f1 / (− f4) = 1.45
Conditional expression (7) β4 = 1.69
Conditional expression (8) ft / f1 = 2.78
Conditional expression (9) f3 / (− f2) = 1.84
Conditional expression (10) (β3t · β2t) / (β3w · β2w) = 26.5
Conditional expression (11) ωt = 1.5 °
Conditional expression (12) ωw = 42.0 °

  From Table 1, it can be seen that the zoom lens ZL1 according to the present example satisfies the conditional expressions (1) to (12).

  FIG. 2 is a diagram illustrating various aberrations (spherical aberration diagram, astigmatism diagram, distortion diagram, coma aberration diagram, and chromatic aberration diagram of magnification) at the photographing distance infinity of the zoom lens ZL1 according to the first example. Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state.

  In each aberration diagram, FNO is an F number, and A is a half field angle (unit: °) with respect to each image height. d indicates the d-line and g indicates the aberration at the g-line. Moreover, those without these descriptions show aberrations at the d-line. In the spherical aberration diagram, the solid line indicates the spherical aberration, and the broken line indicates the sine condition. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. In the coma aberration diagram, the solid line indicates the meridional coma aberration for the d-line and g-line at each incident angle or object height, the broken line on the right side from the origin indicates the sagittal coma aberration generated in the meridional direction with respect to the d-line, and the broken line on the left side from the origin Indicates sagittal coma generated in the sagittal direction with respect to the d-line. Note that the same reference numerals as in this embodiment are used in the aberration diagrams of each embodiment described later.

  As apparent from the respective aberration diagrams shown in FIG. 2, the zoom lens ZL1 according to the first example has excellent aberrations in which various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that it has performance. Since distortion can be sufficiently corrected by image processing after imaging, optical correction is not necessary.

(Second embodiment)
The second embodiment will be described with reference to FIGS. 3 and 4 and Table 2. FIG. As shown in FIG. 3, the zoom lens ZL (ZL2) according to the second example includes a first lens group G1 having a positive refractive power arranged in order from the object side along the optical axis, and a negative refractive power. A second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, The sixth lens group G6 having refractive power.

  The first lens group G1 includes a cemented lens of a meniscus negative lens L11 having a concave surface facing the image side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface on the object side. And a meniscus-shaped positive lens L13 facing the lens.

  The second lens group G2 is arranged in order from the object side along the optical axis, the meniscus negative lens L21 having a concave surface facing the image side, the biconcave negative lens L22, and the convex surface facing the object side. It comprises a meniscus positive lens L23.

  The third lens group G3 includes a meniscus positive lens L31 having a convex surface facing the object side, a biconvex positive lens L32, and a biconcave negative lens L33, which are arranged in order from the object side along the optical axis. It is composed of a cemented lens and a biconvex positive lens L34. The positive lens L31 has two aspheric surfaces.

  The fourth lens group G4 includes a meniscus plastic negative lens L41 having a convex surface directed toward the object side.

  The fifth lens group G5 includes a biconvex positive lens L51.

  The sixth lens group G6 is composed of a biconcave negative lens L61.

  An aperture stop S for adjusting the amount of light is disposed between the second lens group G2 and the third lens group G3.

  On the image side of the sixth lens group G6, a low pass filter LPF for cutting a spatial frequency equal to or higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I, is disposed.

In the zoom lens ZL2 according to the present embodiment, the first lens group G1, the second lens group G2, the aperture stop S, and the like so that the distance between the lens groups changes during zooming from the wide-angle end state to the telephoto end state.
The third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group are moved.

  Table 2 below shows the values of each item in the second embodiment. Surface numbers 1 to 27 in Table 2 correspond to the optical surfaces m1 to m27 shown in FIG.

(Table 2)
[Lens specifications]
Surface number R D nd νd
Object ∞
1 169.269 2.73 1.9538 32.3
2 85.245 9.55 1.4970 81.6
3 -364.120 0.23
4 72.803 5.45 1.6030 65.4
5 308.721 (D5)
6 503.678 1.14 1.8348 42.7
7 15.299 8.86
8 -45.343 1.14 1.8348 42.7
9 81.009 0.45
10 35.726 4.09 1.9460 18.0
11 475.694 (D11)
12 ∞ 1.70 (Aperture S)
* 13 13.057 4.09 1.5920 67.1
* 14 442.624 0.23
15 21.120 3.41 1.4970 81.6
16 -594.967 0.91 1.8830 40.7
17 11.443 1.82
18 25.329 3.18 1.5182 58.8
19 -39.665 (D19)
20 101.362 1.36 1.5311 55.9
21 32.551 (D21)
22 33.364 4.55 1.5311 55.9
23 -52.401 (D23)
24 -220.194 0.91 1.9229 20.9
25 100.129 (D25)
26 ∞ 1.94 1.5168 63.9
27 ∞ (BF)
Image plane ∞

[Overall specifications]
Zoom ratio 32.99
Wide angle end Intermediate focus Telephoto end f 10.0 57.4 329.9
φ 13.64 13.64 13.64
Fno 3.41 5.57 9.91
2ω 86.68 18.28 3.12
BF 2.26 2.26 2.26
BF (Air) 4.78 22.38 4.63
TL 158.1 193.9 219.2
TL (Air) 157.4 193.2 218.6

[Aspherical data]
Surface number κ A4 A6
13 0.701 -7.04E-06 0.00E + 00
14 1.000 6.79E-06 0.00E + 00

[Variable interval data]
Variable interval Wide-angle end Intermediate focus Telephoto end
D5 1.31 47.04 90.60
D11 68.79 17.97 0.50
D19 11.02 14.64 16.12
D21 13.32 30.76 50.16
D23 2.37 4.65 0.78
D25 1.24 18.84 1.09

[Lens group data]
Group number Group first surface Group focal length Lens construction length G1 1 125.0 17.95
G2 6 -17.4 15.68
G3 13 30.7 13.64
G4 20 -90.9 1.36
G5 22 39.1 4.55
G6 24 -74.5 0.91

[Conditional expression]
Conditional expression (1) {β5 ² (1-β4) ² · f1 · (−f4)} / ft ² = 0.026
Conditional expression (2) νdp1 = 73.5
Conditional expression (3) νdn1 = 32.3
Conditional expression (4) β2t / β2w = 9.4
Conditional expression (5) (r41 + r42) / (r41-r42) = 1.95
Conditional expression (6) f1 / (− f4) = 1.38
Conditional expression (7) β4 = 1.66
Conditional expression (8) ft / f1 = 2.64
Conditional expression (9) f3 / (− f2) = 1.76
Conditional expression (10) (β3t · β2t) / (β3w · β2w) = 24.2
Conditional expression (11) ωt = 1.56 °
Conditional expression (12) ωw = 43.34 °

  From Table 2, it can be seen that the zoom lens ZL2 according to the present example satisfies the conditional expressions (1) to (12).

  FIG. 4 is a diagram showing various aberrations (spherical aberration diagram, astigmatism diagram, distortion diagram, coma diagram, and chromatic aberration diagram of magnification) at the photographing distance infinity of the zoom lens ZL2 according to the second example. Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 4, the zoom lens ZL2 according to the second example has excellent aberrations in which various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that it has performance. Since distortion can be sufficiently corrected by image processing after imaging, optical correction is not necessary.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 5 and 6 and Table 3. FIG. As shown in FIG. 5, the zoom lens ZL (ZL3) according to the third example includes a first lens group G1 having a positive refractive power arranged in order from the object side along the optical axis, and a negative refractive power. A second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The

  The first lens group G1 includes a cemented lens of a meniscus negative lens L11 having a convex surface directed toward the object side and a biconvex positive lens L12 arranged in order from the object side along the optical axis, and a convex surface toward the object side. And a meniscus-shaped positive lens L13 facing the lens.

  The second lens group G2 includes a biconcave negative lens L21, a biconcave negative lens L22, and a meniscus positive lens L23 having a convex surface facing the object, which are arranged in order from the object side along the optical axis. It consists of.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex positive lens L31, a cemented lens of a biconvex positive lens L32, and a biconcave negative lens L33, It is composed of a convex positive lens L34. The positive lens L31 has two aspheric surfaces.

  The fourth lens group G4 includes a meniscus plastic negative lens L41 having a convex surface directed toward the object side.

  The fifth lens group G5 includes a biconvex positive lens L51. The positive lens L51 has an aspheric object side surface.

  An aperture stop S for adjusting the amount of light is disposed between the second lens group G2 and the third lens group G3.

  On the image side of the fifth lens group G5, a low-pass filter LPF for cutting a spatial frequency equal to or higher than the limit resolution of the solid-state imaging device, such as a CCD disposed on the image plane I, is disposed.

  In the zoom lens ZL3 according to the present embodiment, the first lens group G1, the second lens group G2, the aperture stop S, and the like so that the distance between the lens groups changes during zooming from the wide-angle end state to the telephoto end state. The third lens group G3 and the fourth lens group G4 are moved. The fifth lens group G5 is fixed with respect to the image plane during zooming.

  Table 3 below shows values of various specifications in the third example. Surface numbers 1 to 25 in Table 3 correspond to the optical surfaces m1 to m25 shown in FIG.

(Table 3)
[Lens specifications]
Surface number R D nd νd
Object ∞
1 176.828 2.94 1.9538 32.3
2 86.780 9.71 1.4970 81.6
3 -336.741 0.23
4 78.084 7.45 1.6030 65.4
5 495.346 (D5)
6 -750.737 1.13 1.8348 42.7
7 16.612 9.26
8 -36.440 1.13 1.6968 55.5
9 83.552 0.45
10 39.164 4.29 1.9460 18.0
11 334.476 (D11)
12 ∞ 1.58 (Aperture S)
* 13 16.733 4.52 1.6226 58.2
* 14 -193.590 0.23
15 19.195 4.74 1.4875 70.3
16 -87.927 0.90 1.8340 37.2
17 13.094 2.26
18 40.381 2.71 1.4970 81.6
19 -39.406 (D19)
20 34.285 1.35 1.5311 55.9
21 17.592 (D21)
* 22 25.885 4.74 1.5311 55.9
23 -873.790 (D23)
24 ∞ 2.12 1.5168 63.9
25 ∞ (BF)
Image plane ∞

[Overall specifications]
Zoom ratio 32.99
Wide angle end Intermediate focus Telephoto end f 10.0 52.9 329.9
φ 14.9 14.9 14.9
Fno 3.53 5.37 6.81
2ω 88.5 18.8 3.1
BF 2.12 2.12 2.12
BF (Air) 4.85 4.85 4.85
TL 172.3 183.2 214.9
TL (Air) 171.6 182.5 214.2

[Aspherical data]
Surface number κ A4 A6
13 0.8277 -4.92E-06 0.00E + 00
14 1.0000 1.05E-05 0.00E + 00
22 1.0000 1.16E-05 7.71E-08

[Variable interval data]
Variable interval Wide-angle end Intermediate focus Telephoto end
D5 1.03 46.82 87.81
D11 77.89 22.54 0.48
D19 6.19 36.21 26.15
D21 22.00 12.48 35.28
D23 1.33 1.33 1.33

[Lens group data]
Group number Group first surface Group focal length Lens construction length G1 1 123.0 20.32
G2 6 -16.9 16.26
G3 13 30.5 15.36
G4 20 -70.0 1.35
G5 22 47.4 4.74

[Conditional expression]
Conditional expression (1) {β5 ² (1-β4) ² · f1 · (−f4)} / ft ² = 0.022
Conditional expression (2) νdp1 = 73.5
Conditional expression (3) νdn1 = 32.3
Conditional expression (4) β2t / β2w = 9.3
Conditional expression (5) (r41 + r42) / (r41-r42) = 3.11
Conditional expression (6) f1 / (− f4) = 1.76
Conditional expression (7) β4 = 1.63
Conditional expression (8) ft / f1 = 2.68
Conditional expression (9) f3 / (− f2) = 1.81
Conditional expression (10) (β3t · β2t) / (β3w · β2w) = 29.1
Conditional expression (11) ωt = 1.55 °
Conditional expression (12) ωw = 44.25 °

  From Table 3, it can be seen that the zoom lens ZL3 according to the present example satisfies the conditional expressions (1) to (12).

  FIG. 6 is a diagram illustrating various aberrations (spherical aberration diagram, astigmatism diagram, distortion diagram, coma diagram, and chromatic aberration diagram of magnification) at the photographing distance infinity of the zoom lens ZL3 according to Example 3, and (a) Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state.

  As apparent from the respective aberration diagrams shown in FIG. 6, the zoom lens ZL3 according to the third example has excellent aberrations in which various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state. It can be seen that it has performance. Since distortion can be sufficiently corrected by image processing after imaging, optical correction is not necessary.

  According to each of the embodiments described above, it is possible to realize a zoom lens having high optical performance while having a high zoom ratio.

  In order to make the present invention easy to understand, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this. The following contents can be appropriately adopted as long as the optical performance of the zoom lens ZL of the present application is not impaired.

  As a numerical example of the zoom lens ZL according to the present embodiment, a lens having a 5-group or 6-group configuration is shown. . Specifically, a configuration in which a lens or a lens group is added closest to the object side or a configuration in which a lens or a lens group is added closest to the image side may be used. The lens group indicates a portion having at least one lens separated by an air interval that changes at the time of zooming or focusing.

  In the zoom lens ZL according to the present embodiment, in order to focus from infinity to a short distance object, a part of the lens group, one entire lens group, or a plurality of lens groups is used as the focusing lens group, and the optical axis It is good also as a structure moved to a direction. This focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (using an ultrasonic motor or the like). In particular, it is preferable that at least a part of the fourth lens group G4 or the fifth lens group G5 is a focusing lens group.

  In the zoom lens ZL according to the present embodiment, either the entire lens group or the partial lens group is moved so as to have a component in a direction perpendicular to the optical axis, or rotated in an in-plane direction including the optical axis ( The image stabilizing lens group may be configured to correct image blur caused by camera shake or the like. In particular, it is preferable that at least a part of the third lens group G3 is an anti-vibration lens group.

  In the zoom lens ZL according to the present embodiment, the lens surface may be formed as a spherical surface, a flat surface, or an aspherical surface. When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and optical performance deterioration due to errors in processing and assembly adjustment can be prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. When the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  In the zoom lens ZL according to the present embodiment, the aperture stop S is preferably disposed between the second lens group G2 to the fourth lens group G4, but without providing a member as the aperture stop, the lens frame is provided. You may substitute that role.

  In the zoom lens ZL according to the present embodiment, each lens surface may be provided with an antireflection film having high transmittance in a wide wavelength region in order to reduce flare and ghost and achieve high contrast and high optical performance. .

  The zoom lens ZL according to the present embodiment has a zoom ratio of about 15 to 80 times.

ZL (ZL1 to ZL3) Zoom lens G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group S Aperture stop LPF Low pass filter I Image plane 1 Camera ( Optical equipment)

Claims (18)

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, arranged in order from the object side along the optical axis, and a negative A fourth lens group having a refractive power and a fifth lens group having a positive refractive power;
The fourth lens group includes a plastic negative lens;
A zoom lens satisfying the following conditional expression:
0.020 <{β5 ² (1-β4) ² · f1 · (−f4)} / ft ² <0.035
However,
ft: focal length of the entire system in the telephoto end state,
f1: the focal length of the first lens group,
f4: focal length of the fourth lens group,
β4: magnification of the fourth lens group in the telephoto end state,
β5: A composite magnification of the lens group disposed on the image side of the fourth lens group in the telephoto end state.   2. The zoom lens according to claim 1, wherein the distance between the lens units changes upon zooming from the wide-angle end state to the telephoto end state.   3. The zoom lens according to claim 1, wherein the first lens group to the fourth lens group move during zooming from the wide-angle end state to the telephoto end state.   4. The zoom lens according to claim 1, wherein the first lens unit to the fifth lens unit move during zooming from the wide-angle end state to the telephoto end state. 5. The first lens group includes a positive lens;
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
65.0 <νdp1 <100.0
However,
νdp1: Average value of Abbe numbers of positive lenses in the first lens group. The first lens group has a negative lens;
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
23.0 <νdn1 <38.0
However,
νdp1: The average value of the Abbe number of the negative lens included in the first lens group. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
5.0 <β2t / β2w <13.0
However,
β2w: magnification of the second lens group in the wide-angle end state;
β2t: magnification of the second lens group in the telephoto end state. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.50 <(r41 + r42) / (r41-r42) <3.50
However,
r41: radius of curvature of the surface closest to the object side of the fourth lens group,
r42: radius of curvature of the most image-side surface of the fourth lens group. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.00 <f1 / (− f4) <4.00 The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.50 <β4 <2.00 The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
2.20 <ft / f1 <2.90 The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.50 <f3 / (− f2) <2.00
However,
f2: focal length of the second lens group,
f3: focal length of the third lens group. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
22.0 <(β3t · β2t) / (β3w · β2w) <32.0
However,
β2w: magnification of the second lens group in the wide-angle end state β2t: magnification of the second lens group in the telephoto end state,
β3w: magnification of the third lens group in the wide-angle end state;
β3t: magnification of the third lens group in the telephoto end state.   The zoom lens according to claim 1, wherein the fourth lens group includes a plastic negative lens. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
0.10 ° <ωt <10.00 °
However,
ωt: Half angle of view in the telephoto end state. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
20.00 ° <ωw <80.00 °
However,
ωw: Half angle of view in the wide-angle end state.   An optical apparatus comprising the zoom lens according to any one of claims 1 to 16. 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, arranged in order from the object side along the optical axis, and a negative A method of manufacturing a zoom lens having a fourth lens group having a refractive power and a fifth lens group having a positive refractive power,
The fourth lens group includes a plastic negative lens;
To satisfy the following conditional expression,
A method of manufacturing a zoom lens, wherein each lens is arranged in a lens barrel.
0.020 <{β5 ² (1-β4) ² · f1 · (−f4)} / ft ² <0.035
However,
ft: focal length of the entire system in the telephoto end state,
f1: the focal length of the first lens group,
f4: focal length of the fourth lens group,
β4: magnification of the fourth lens group in the telephoto end state,
β5: A composite magnification of the lens group disposed on the image side of the fourth lens group in the telephoto end state.

Images