Zoom lens and imaging device

Abstract

In zoom lenses, we aim to achieve miniaturization, wider angle, and high optical performance. [Solution] The zoom lens is composed of a first lens group L1 with positive refractive power that does not move for zooming, an intermediate group including at least three moving lens groups L2 to L4 that move for zooming, and a rear lens group L5 with positive refractive power that does not move for zooming. The zoom lens has five or more aspherical surfaces. The first lens group is composed of seven or more lenses. The first lens group includes a focusing group that moves for focusing. When TL is the distance on the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0

Description

Technical Field

[0001] The present invention relates to a zoom lens suitable for imaging.

Background Art

[0002] Zoom lenses are desired to be small in size while having a wide angle of view and high optical performance. Patent Document 1 discloses a zoom lens having, in order from the object side to the image side, a first lens group with a positive refractive power that does not move for zooming, a plurality of lens groups that move for zooming, and a rear lens group with a positive refractive power that does not move for zooming. The first lens group of this zoom lens includes a focus group that moves for focusing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the zoom lens disclosed in Patent Document 1, when miniaturizing while achieving high specifications such as an increase in the angle of view and a high zoom ratio, various aberrations during zooming and focusing vary, making it difficult to obtain high optical performance.

Means for Solving the Problems

[0005] One aspect of the present invention is a zoom lens, which includes a plurality of lens groups. The plurality of lens groups consist of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The zoom lens has five or more aspherical surfaces. The first lens group consists of seven or more lenses. The first lens group includes a focusing group that moves for focusing. When TL is the distance on the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0 <TL / fw≦53 It is characterized by satisfying the following conditions. Furthermore, an imaging device equipped with the above-mentioned zoom lens also constitutes another aspect of the present invention. [Effects of the Invention]

[0006] This invention can provide a zoom lens that is compact yet has a wide field of view and high optical performance. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the zoom lens of Example 1. [Figure 2] Aberration diagrams of the zoom lens of Example 1 at the (A) wide-angle end and (B) telephoto end. [Figure 3] Cross-sectional view of the zoom lens in Example 2. [Figure 4] Aberration diagrams of the zoom lens of Example 2 at the (A) wide-angle end and (B) telephoto end. [Figure 5] Cross-sectional view of the zoom lens of Example 3. [Figure 6] Aberration diagrams of the zoom lens of Example 3 at the (A) wide-angle end and (B) telephoto end. [Figure 7] Cross-sectional view of the zoom lens of Example 4. [Figure 8] Aberration diagrams of the zoom lens of Example 4 at the (A) wide-angle end and (B) telephoto end. [Figure 9] Cross-sectional view of the zoom lens of Example 5. [Figure 10] Aberration diagrams of the zoom lens of Example 5 at the (A) wide-angle end and (B) telephoto end. [Figure 11] Cross-sectional view of the zoom lens of Example 6. [Figure 12] Aberration diagrams of the zoom lens of Example 6 at the (A) wide-angle end and (B) telephoto end. [Figure 13] A diagram showing the aspherical shape of the second lens in Examples 1 to 4. [Figure 14] A diagram showing an imaging device equipped with a zoom lens according to Examples 1 to 6. [Modes for carrying out the invention]

[0008] The embodiments of the present invention will be described below with reference to the drawings. First, before describing the specific embodiments 1 to 5, we will explain the matters common to each embodiment.

[0009] The zoom lenses in each embodiment can be used in various imaging devices such as cinema cameras, broadcast cameras, video cameras, surveillance cameras, digital still cameras, and silver halide film cameras.

[0010] In a zoom lens, a lens group is a collection of one or more lenses that move together or remain stationary during zooming between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming. A lens group may include an aperture diaphragm. The wide-angle and telephoto ends represent the zoom states at the maximum angle of view (shortest focal length) and minimum angle of view (longest focal length), respectively, when the lens group that moves during zooming is positioned at the two ends of the range that is mechanically or controllly movable along the optical axis.

[0011] Figures 1, 3, 5, 7, 9, and 11 each show a cross-section of the zoom lens of Examples 1 to 6 in a state focused on an infinite object (hereinafter referred to as an infinite focus state) and at the wide-angle end. In each figure, the left side is the object side (front side), and the right side is the image side (rear side). OA indicates the optical axis of the zoom lens. Li is the i-th lens group counted from the object side (i = 1, 2, 3,...), and L1m is the m-th sub-lens group counted from the object side in the first lens group L1 (m = 1, 2, 3,...). G1 and G2 are the lenses closest to the object side and the second lens counted from the object side among the plurality of lenses constituting the first lens group L1, respectively. SP is the aperture stop, and I is the image plane. On the image plane I, the imaging surface (light-receiving surface) of the imaging element in the imaging device and the film surface (photosensitive surface) of the silver halide film are arranged.

[0012] Under the lens group that moves during zooming, the movement trajectory of the lens group during zooming from the wide-angle end to the telephoto end is indicated by an arrow. Further, under the lens group (sub-lens group) that moves during focusing, the movement direction of the lens group during focusing from infinity to the closest distance is indicated by an arrow marked with FOCUS.

[0013] The zoom lens of each example includes a plurality of lens groups. The plurality of lens groups includes a first lens group L1 with a positive refractive power that does not move for zooming, an intermediate group including at least three moving lens groups that move for zooming, and a rear lens group with a positive refractive power that does not move for zooming, which are arranged in order from the object side to the image side. The zoom lens has five or more aspherical surfaces. The first lens group L1 is composed of seven or more lenses. Note that one cemented lens in which two lenses are cemented is counted as two lenses. Further, the first lens group L1 includes a focus group that moves for focusing. <{

[0014] When the distance on the optical axis from the most object-side surface of the zoom lens of each example to the image plane (total lens length) is TL and the focal length of the zoom lens at the wide-angle end is fw, the condition of the following formula (1) is satisfied.

[0015] 0 < TL / fw ≤ 53 (1) The condition of Equation (1) indicates an appropriate relationship between the overall length of the lens and the focal length of the entire system in order to obtain high optical performance across the entire focusing range with a wide angle of view while being compact. When TL / fw exceeds the upper limit of Equation (1), the overall length of the lens becomes too long with respect to the focal length at the wide-angle end, making miniaturization difficult. Also, the outermost marginal ray determines the diameter of the lens arranged closest to the object side. At this time, when the overall length of the lens increases, the diameter of the lens increases, making it difficult to achieve both wide-angle and miniaturization, which is not preferable. When TL / fw is below the lower limit of Equation (1), the focal length at the wide-angle end becomes a negative value, and intermediate imaging occurs within the zoom lens. As a result, the overall length of the lens increases in order to re-image at the image plane, making miniaturization of the zoom lens difficult, which is not preferable.

[0016] Note that it is more preferable that the upper limit of Equation (1) be 50, 45, 40, 35, or 30. Also, it is more preferable that the lower limit of Equation (1) be 1, 3, 5, 8, or 10.

[0017] By satisfying the above configuration and the condition of Equation (1), a zoom lens that is compact while having a wide angle and high optical performance can be realized.

[0018] Also, it is preferable that the zoom lens of each embodiment satisfy at least one of the conditions of the following Equations (2) and (3).

[0019] 1 ≤ f1 / fw ≤ 12 (2) -8 ≤ f1 / f2 < 0 (3) In Equations (2) and (3), f1 is the focal length of the first lens group L1, and f2 is the focal length of the moving lens group having the strongest negative refractive power among at least one moving lens group with negative refractive power included in the intermediate group.

[0020] The conditions in equation (2) indicate an appropriate relationship between the focal length of the first lens group L1 and the focal length of the entire system at the wide-angle end in order to obtain a zoom lens that is compact yet has a wide angle of view, a high zoom ratio, and high optical performance. If f1 / fw exceeds the upper limit of equation (2), the diameter of the first lens group L1 becomes large, making it difficult to obtain a compact zoom lens, which is undesirable. If f1 / fw falls below the lower limit of equation (2), it becomes difficult to obtain a zoom lens with a wide angle of view and a high zoom ratio, or it becomes difficult to keep aberrations at the wide-angle end within an acceptable range, which is also undesirable.

[0021] The conditions in equation (3) indicate an appropriate relationship between the focal length of the first lens group L1 and the movable lens group with negative refractive power included in the intermediate group. Satisfying the conditions in equation (3) makes it possible to achieve a refractive power arrangement that is advantageous for miniaturization, weight reduction, and high magnification as a zoom lens. If f1 / f2 exceeds the upper limit of equation (3), the refractive power of the negative movable lens group becomes too weak compared to the refractive power of the first lens group L1, making it difficult to achieve high magnification, which is undesirable. If f1 / f2 falls below the lower limit of equation (3), the refractive power of the negative movable lens group becomes too strong, resulting in large aberration fluctuations during zooming, and it becomes difficult to achieve miniaturization and weight reduction in order to suppress these aberration fluctuations, which is also undesirable.

[0022] Furthermore, it is more preferable to set the upper limit of equation (2) to 11.5, 11, 10.5, or 10. Also, it is more preferable to set the lower limit of equation (2) to 1.2, 1.5, 1.8, or 2.

[0023] Furthermore, it is preferable to set the upper limit of equation (3) to -0.1, -0.3, -0.5, or -0.7. Also, it is preferable to set the lower limit of equation (3) to -7.8, -7.5, -7.3, or -7.

[0024] The zoom lens of each embodiment preferably has at least one of the following configurations.

[0025] The object-side surface of the first lens G1, which is positioned closest to the object in the first lens group L1, is preferably aspherical. This configuration makes it possible to effectively correct distortion at the wide-angle end.

[0026] The object-side surface of the second lens G2, which is adjacent to the first lens L1 on the image side, is preferably aspherical. This configuration makes it possible to effectively correct field curvature at the wide-angle end. In this configuration, the aspherical surface of the object-side surface of the second lens G2 is preferably an aspherical surface in which the sign of curvature does not reverse in the radial direction. This is preferable because reversing the sign of curvature increases the difficulty of processing, while not reversing it results in a shape that is easy to process.

[0027] In each embodiment of the zoom lens, it is preferable that one of the moving lens groups included in the intermediate group has an aspherical surface. This configuration makes it possible to suppress variations in various aberrations due to zooming.

[0028] In the zoom lens of each embodiment, it is preferable that the first lens group L1 has a second sub-lens group L12 with positive refractive power, which is the focusing group. Furthermore, it is preferable that the first lens group L1 has a first sub-lens group L11 with negative refractive power, which is positioned closer to the object than the second sub-lens group L12 and does not move for focusing, and a third sub-lens group L13 with positive refractive power, which is positioned closer to the image than the second focusing group L12 and does not move for focusing. This configuration makes it possible to suppress aberration fluctuations due to focusing.

[0029] In each embodiment, it is preferable that the zoom lens does not form an intermediate image between the surface closest to the object (first lens G1) and the image plane I. If an intermediate image is formed, it is necessary to re-image at the image plane I, which increases the number of lenses constituting the zoom lens and makes the zoom lens larger. In contrast, if an intermediate image is not formed, the zoom lens can be made smaller.

[0030] The zoom lenses of Examples 1 to 5 will be described in detail below. Following Example 5, numerical examples 1 to 5 corresponding to each of Examples 1 to 5 will be shown. [Examples]

[0031] The zoom lens of Embodiment 1 (Numerical Example 1) shown in Figure 1 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0032] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The first sub-lens group L11 consists of four lenses, including the first lens G1 with negative refractive power, which is the closest to the object in the first lens group L1, and the second lens G2 with negative refractive power, which is adjacent to the first lens G1 on the image side. The first sub-lens group L11 is fixed and does not move during focusing. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close, and consists of a single lens with positive refractive power. The third sub-lens group L13 is fixed and does not move during focusing. The first lens group L1 consists of a total of 10 lenses arranged in order from the object side to the image side: a negative lens (G1), a negative lens (G2), a negative lens, a positive lens, a positive lens (L12), a joined negative lens and a positive lens, and a joined positive lens, a negative lens, and a positive lens.

[0033] The second lens group L2 is a variator group with negative refractive power and moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each act as compensator groups and move toward the image side when zooming from the wide-angle end to the telephoto end. Optical units such as an extender lens for focal length conversion may be inserted into the space within the fifth lens group L5.

[0034] In this embodiment, the object-side surface of the first lens G1, the object-side surface of the second lens G2, the image-side surface of the single lens constituting the second sub-lens group L12, the object-side surface of the second lens group L2, and the object-side surface of the single lens constituting the fourth lens group L4 are aspherical.

[0035] Figure 11(A) shows the aspherical shape of the object-side surface of the second lens G2 in the zoom lens of numerical example 1. The vertical axis shows the radial position of the object-side surface of the second lens G2 in a cross-section containing the optical axis OA, and the horizontal axis shows the curvature [1 / mm] of the object-side surface of the second lens G2. The numerical values ​​on the vertical axis represent the distance from the optical axis OA to each position when normalized so that the distance from the optical axis OA to the position of the maximum effective diameter (the maximum diameter of the region through which light rays contributing to image formation pass) is 1. The same applies to Figures 13(B) to (D) which show the aspherical shape of the object-side surface of the second lens G2 in numerical examples 2 to 4 described later.

[0036] Figure 2(A) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens of numerical example 1 at infinity focus and the wide-angle end. Figure 2(B) shows the longitudinal aberrations of the zoom lens of numerical example 1 at infinity focus and the telephoto end.

[0037] In the spherical aberration diagram, Fno indicates the F number. The solid line shows the spherical aberration for the d line (wavelength 587.6 nm), the dashed line shows the spherical aberration for the g line (wavelength 435.8 nm), the dashed line shows the spherical aberration for the C line (wavelength 656.3 nm), and the long dashed line shows the spherical aberration for the F line (wavelength 486.1 nm). In the astigmatism diagram, the solid line S shows astigmatism on the sagittal image plane, and the dashed line M shows astigmatism on the meridional image plane. The distortion diagram shows distortion at the d line. The chromatic aberration diagram shows lateral chromatic aberration at the g, C, and F lines. The astigmatism and chromatic aberration diagrams show the amount of aberration when the central ray of the light beam at the aperture position is considered the principal ray. ω is the paraxial half-angle of view (°). Spherical aberration is depicted on a scale of 0.2 mm, astigmatism on 0.2 mm, distortion on 5%, and chromatic aberration on 0.05 mm. The explanation for the above aberration diagrams also applies to the aberration diagrams in the following numerical examples. [Examples]

[0038] The zoom lens of Embodiment 2 (Numerical Example 2) shown in Figure 3 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, an aperture diaphragm SP, and a sixth lens group L6 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5 are movable lens groups that move for zooming and constitute an intermediate group. The sixth lens group L6 is a rear lens group for image formation and does not move for zooming.

[0039] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The first sub-lens group L11 consists of three lenses, including the first lens G1 with negative refractive power, which is closest to the object in the first lens group L1, and the second lens G2 with negative refractive power, which is adjacent to the first lens G1 on the image side. The first sub-lens group L11 is fixed and does not move during focusing. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close, and consists of a single lens with positive refractive power. The third sub-lens group L13 is fixed and does not move during focusing. The first lens group L1 consists of a total of 10 lenses arranged in order from the object side to the image side: a negative lens (G1), a negative lens (G2), a positive lens, a positive lens (L12), a joined positive and negative lens, a joined negative and positive lens, and a positive lens.

[0040] The second lens group L2 and the third lens group L3, together, form a variator group with negative refractive power, and each moves toward the image side when zooming from the wide-angle end to the telephoto end. The fourth lens group L4 and the fifth lens group L5 each act as a compensator group and move toward the image side when zooming from the wide-angle end to the telephoto end. Optical units such as an extender lens for focal length conversion may be inserted into the space within the sixth lens group L6.

[0041] In this embodiment, the object-side surface of the first lens G1, the object-side surface of the second lens G2, the image-side surface of the single lens constituting the second sub-lens group L12, the image-side surface of the first lens group L1, the object-side surface of the second lens group L2, and the object-side surface of the fifth lens group L5 are aspherical.

[0042] Figure 11(B) shows the aspherical shape of the object-side surface of the second lens G2 in numerical example 2.

[0043] Figure 4(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 2. Figure 4(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 2. [Examples]

[0044] The zoom lens of Embodiment 3 (Numerical Example 3) shown in Figure 5 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0045] The first lens group L1 consists of three sub-lens groups: a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The first sub-lens group L11 consists of four lenses, including the first lens G1 with negative refractive power, which is closest to the object in the first lens group L1, and the second lens G2 with negative refractive power, which is adjacent to the first lens G1 on the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close, and consists of a single lens with positive refractive power. The first lens group L1 consists of a total of 10 lenses, arranged in order from the object side to the image side: a negative lens (G1), a negative lens (G2), a negative lens, a positive lens, a positive lens (L12), a joined positive and negative lens, a joined negative and positive lens, and a positive lens.

[0046] The second lens group L2 is a variator group with negative refractive power and moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each act as compensator groups and move toward the image side when zooming from the wide-angle end to the telephoto end. Optical units such as an extender lens for focal length conversion may be inserted into the space within the fifth lens group L5.

[0047] In this embodiment, the object-side surface of the first lens G1, the object-side surface of the second lens G2, the image-side surface of the single lens constituting the second sub-lens group L12, the object-side surface of the second lens group L2, the image-side surface of the third lens group L3, and the object-side surface of the lens adjacent to the aperture diaphragm SP on the image side of the fourth lens group L4 are aspherical.

[0048] Figure 11(C) shows the aspherical shape of the object-side surface of the second lens G2 in numerical example 3.

[0049] Figure 6(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 3. Figure 6(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 3. [Examples]

[0050] The zoom lens of Embodiment 4 (Numerical Example 4) shown in Figure 7 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side.

[0051] The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute the intermediate group. The fifth lens group L5 is the rear lens group for image formation and does not move for zooming.

[0052] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The first sub-lens group L11 consists of three lenses, including the first lens G1 with negative refractive power, which is closest to the object in the first lens group L1, and the second lens G2 with negative refractive power, which is adjacent to the first lens G1 on the image side. The first sub-lens group L11 is fixed and does not move during focusing. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close, and consists of a single lens with positive refractive power. The third sub-lens group L13 is fixed and does not move during focusing. The first lens group L1 consists of a total of eight lenses arranged in order from the object side to the image side: a negative lens (G1), a negative lens (G2) and a positive lens, a positive lens (L12), a joined negative lens and a positive lens, and two positive lenses.

[0053] The second lens group L2 is a variator group with negative refractive power, and moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 are compensator groups, respectively, and move toward the object side and the image side when zooming from the wide-angle end to the telephoto end.

[0054] An optical unit, such as a focal length conversion extender lens, may be inserted in the space between the fourth lens group L4 and the fifth lens group L5.

[0055] In this embodiment, the object-side surface of the first lens G1, the object-side surface of the second lens G2, the image-side surface of the single lens constituting the second sub-lens group L12, the object-side surface of the second lens group L2, and the object-side surface of the lens adjacent to the aperture diaphragm SP on the image side of the fourth lens group L4 are aspherical.

[0056] Figure 11(D) shows the aspherical shape of the object-side surface of the second lens G2 in numerical example 4.

[0057] Figure 8(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 4. Figure 8(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 4. [Examples]

[0058] The zoom lens of Embodiment 5 (Numerical Example 5) shown in Figure 9 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0059] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, a third sub-lens group L13 with negative refractive power, and a fourth sub-lens group L14 with positive refractive power, arranged in order from the object side to the image side. The first sub-lens group L11 consists of the first lens G1 with negative refractive power, which is closest to the object in the first lens group L1, and the second lens G2 with positive refractive power, which is adjacent to the first lens G1 on the image side. The first sub-lens group L11 is fixed and does not move during focusing. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close, and consists of a single lens with positive refractive power. The third sub-lens group L13 is fixed and does not move during focusing. The fourth sub-lens group L14 is a focusing group that moves towards the object side when focusing from infinity to close. The first lens group L1 consists of a total of seven lenses arranged in order from the object side to the image side: a negative lens (G1), a positive lens (G2), a positive lens (L12), a joined negative lens and positive lens, and two positive lenses.

[0060] The second lens group L2 is a variator group with negative refractive power, and moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 are compensator groups, respectively, and move toward the object side and the image side when zooming from the wide-angle end to the telephoto end.

[0061] An optical unit, such as an extender lens for focal length conversion, may be inserted into the space within the fifth lens group L5.

[0062] In this embodiment, the image-side surface of the single lens constituting the second sub-lens group L12, the object-side surface of the second lens group L2, the image-side surface of the second lens group L2, the image-side surface of the third lens group L3, and the object-side surface of the fourth lens group L4 are aspherical.

[0063] Figure 10(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 5. Figure 10(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 5. [Examples]

[0064] The zoom lens of Embodiment 6 (Numerical Example 6) shown in Figure 11 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, an aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0065] The first lens group L1 consists of three lenses arranged in order from the object side to the image side: the first sub-lens group L11 with negative refractive power, the second sub-lens group L12 with positive refractive power, and the third sub-lens group L13 with positive refractive power. The first sub-lens group L11 consists of three lenses, including the first lens G1 with negative refractive power, which is closest to the object in the first lens group L1, and the second lens G2 with positive refractive power, which is adjacent to the first lens G1 on the image side. The second sub-lens group L12 is a focus group that moves towards the object side when focusing from infinity to close. The third sub-lens group L13 is a focus group that moves towards the object side when focusing. The first lens group L1 consists of a total of seven lenses arranged in order from the object side to the image side: a negative lens (G1), a positive lens (G2), a positive lens (L12), a joined negative lens and a positive lens, and two positive lenses.

[0066] The second lens group L2 is a variator group with negative refractive power, and moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each act as compensator groups, and move toward the object side when zooming from the wide-angle end to the telephoto end.

[0067] In this embodiment, the object-side surface of the second lens group L2, the object-side surface of the third lens group L3, the object-side surface of the fourth lens group L4, the image-side surface of the 12th lens from the object side of the fifth lens group L5, and the image-side surface of the fifth lens group L5 are aspherical.

[0068] Figure 12(A) shows the longitudinal aberrations of the zoom lens of numerical example 6 at infinity focus and the wide-angle end. Figure 12(B) shows the longitudinal aberrations of the zoom lens of numerical example 6 at infinity focus and the telephoto end. In this embodiment, spherical aberration is depicted on a scale of 0.4 mm, astigmatism on 0.4 mm, distortion on 5%, and chromatic aberration on 0.05 mm. In Examples 1 to 6, the number of aspherical surfaces was 5 or 6, but it may also have 7 or more aspherical surfaces.

[0069] Numerical examples 1 to 6 are shown below. In each numerical example, the surface number i indicates the order of the surfaces from the object side, r is the radius of curvature of the i-th surface (mm), and d is the distance on the optical axis between the i-th surface and the (i+1)-th surface (mm). The (variable) of the distance d indicates the distance that changes during zooming, and the distance according to the focal length is shown in a separate table. nd is the absolute refractive index at 1 atmosphere at the d-line of the optical material between the i-th surface and the (i+1)-th surface. νd is the Abbe number of the optical material between the i-th surface and the (i+1)-th surface with respect to the d-line. The Abbe number νd with respect to the d-line is given by Nd, NF, and NC, respectively, when the refractive indices at the d-line, F-line, and C-line are Nd, NF, and NC. It is expressed as νd = (Nd-1) / (NF-NC).

[0070] θgF is the partial dispersion ratio of the optical material between the i-th plane and the (i+1)-th plane with respect to the g-line and the F-line. The partial dispersion ratio of the g-line and the F-line is given by, when the refractive index at the g-line is Ng, θgF = (Ng - NF) / (NF - NC) It is represented as follows.

[0071] Each numerical example also shows the half-angle of view (°) of the zoom lens, in addition to the specifications such as the focal length and F-number of the entire zoom lens system. BF is the back focus, which indicates the air-equivalent distance from the image-side lens surface (final surface) to the image plane of the zoom lens. The total lens length is the distance along the optical axis from the object-side lens surface (frontmost) to the final surface of the zoom lens, plus the back focus. Furthermore, the lens group data shows the focal length of each lens group.

[0072] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where X is the displacement from the surface vertex in the optical axis direction, H is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, k is the cone constant, and A3 to A16 are the aspherical coefficients. The cone constant and aspherical coefficients "e±x" are multiplied by 10. ±x It means...

[0073]

number

[0074] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd θgF 1* 42606.960 2.15 1.89190 37.1 0.5780 2 27.149 13.48 3* 58.306 1.50 1.76385 48.5 0.5589 4 36.394 14.57 5 -48.784 1.40 1.90525 35.0 0.5848 6 -139.348 0.20 7 179.434 6.60 1.89286 20.4 0.6393 8 -95.675 3.64 9 1043.755 7.00 1.59522 67.7 0.5442 10* -68.849 4.43 11 1328.657 1.70 2.00069 25.5 0.6136 12 58.203 12.40 1.49700 81.5 0.5375 13 -103.477 0.21 14 -1068.202 14.28 1.43875 94.7 0.5340 15 -39.902 2.00 1.91650 31.6 0.5911 16 -47.581 0.20 17 23517.470 8.27 1.69930 51.1 0.5552 18 -75.192 (variable) 19* -125.330 1.20 1.69930 51.1 0.5552 20 35.256 3.86 21 -220.824 0.82 1.88300 40.8 0.5667 22 25.736 5.81 1.78880 28.4 0.6009 23 -147.111 (variable) 24 -40.955 0.85 1.53775 74.7 0.5392 25 45.600 2.10 1.85478 24.8 0.6122 26 74.105 (Variable) 27* 42.580 5.03 1.73800 32.3 0.5900 28 285.359 (variable) 29 (aperture) ∞ 1.00 30 56.171 1.30 2.05090 26.9 0.6054 31 38.832 6.45 1.53172 48.8 0.5631 32 -318.824 0.42 33 71.419 12.00 1.48749 70.2 0.5300 34 -36.119 1.30 2.00100 29.1 0.5997 35 -113.167 41.07 36 59.085 7.09 1.43875 94.7 0.5340 37 -57.872 6.06 38 -83.704 1.20 2.00100 29.1 0.5997 39 37.639 7.27 1.89286 20.4 0.6393 40 -75.902 0.30 41 48.469 9.55 1.43875 94.7 0.5340 42 -28.911 1.71 2.00100 29.1 0.5997 43 74.397 0.20 44 38.078 7.37 1.48749 70.2 0.5300 45 -77.399 42.48 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4= 1.84806e-05 A 6= 1.22511e-07 A 8= 1.72935e-09 A10= 5.44089e-12 A12= 3.71223e-15 A14= 1.19089e-19 A16=-3.17244e-23 A 3=-5.50989e-05 A 5=-1.04907e-06 A 7=-1.74321e-08 A 9=-1.16501e-10 A1= -1.75300e-13 A13=-4.44063e-17 A15= 3.53356e-21 The 3rd surface k = 0.00000e+00 A 4=-1.16790e-05 A 6=-2.08251e-07 A 8=-1.47790e-09 A10=-1.44163e-13 A12= 4.86545e-15 A14= 1.20477e-18 A 3= 4.09795e-05 A 5= 1.39718e-06 A 7= 2.21440e-08 A 9= 5.34933e-11 A11=-9.07942e-14 A13=-1.19736e-16 The 10th surface k = 0.00000e+00 A 4= 1.89977e-06 A 6=-8.05631e-10 A 8=-5.52707e-13 A 3= 3.80032e-06 A 5= 1.35474e-08 A 7= 1.53113e-11 The 19th surface k = 0.00000e+00 A 4= 4.23146e-06 A 6=-1.89360e-07 A 8=-2.71304e-09 A10=-1.38629e-11 A12=-1.37448e-14 A 3= 1.88284e-06 A 5= 4.88427e-07 A 7= 2.93381e-08 A 9= 2.00605e-10 A11= 6.65827e-13 Page 27 k = 0.00000e+00 A 4=-2.00990e-06 A 6= 1.28494e-08 A 8= 1.11305e-11 A 3=-1.12208e-06 A 5=-9.53336e-08 A 7=-6.19970e-10 Various data Zoom ratio 4.79 Wide-angle, Medium, Telephoto Focal length 11.48 29.42 55.01 F-numbers: 2.72, 2.73, 3.66 Half-angle (°): 52.20 26.71 15.06 Image height 14.80 14.80 14.80 Lens length 321.01 321.01 321.01 BF 42.48 42.48 42.48 d18 1.09 36.15 51.18 d23 32.77 4.24 5.29 d26 10.43 9.60 1.11 d28 16.22 10.52 2.95 Lens group data Group starting plane focal length 1 1 28.85 2 19 -36.48 3 24 -56.10 4 27 67.22 5 29 71.59 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd θgF 1* 1321.162 2.80 1.80100 35.0 0.5864 2 43.517 28.10 3* -72.918 2.20 1.63854 55.4 0.5484 4 240.297 0.15 5 158.845 8.15 1.95906 17.5 0.6598 6 -383.569 1.14 7 200.391 13.70 1.53775 74.7 0.5392 8* -95.836 5.63 9 244.285 12.74 1.48749 70.2 0.5300 10 -95.713 2.10 1.84666 23.8 0.6205 11 -193.393 0.20 12 146.312 2.10 1.80518 25.4 0.6161 13 57.266 14.69 1.43875 94.7 0.5340 14 -998.903 0.20 15 213.979 6.00 1.43875 94.7 0.5340 16 -300.610 0.37 17 187.273 8.47 1.76385 48.5 0.5589 18* -146.619 (variable) 19* 101.537 1.25 2.00100 29.1 0.5997 20 24.654 6.58 21 -46.908 0.90 1.59522 67.7 0.5442 22 29.988 6.10 1.85478 24.8 0.6122 23 -78.709 (variable) 24 -26.718 0.90 1.83481 42.7 0.5648 25 -43.533 (variable) 26 -35.656 0.90 1.59522 67.7 0.5442 27 91.800 2.14 1.78880 28.4 0.6009 28 728.506 (variable) 29* 72.442 7.49 1.90525 35.0 0.5848 30 -121.473 (variable) 31 (aperture) ∞ 1.80 32 352.369 1.10 2.00100 29.1 0.5997 33 43.232 10.20 1.49700 81.5 0.5375 34 -54.772 0.20 35 60.280 7.06 1.48749 70.2 0.5300 36 -62.210 1.10 1.80400 46.5 0.5577 37 480.393 41.38 38 70.560 7.91 1.43875 94.7 0.5340 39 -49.427 4.20 40 370.943 8.26 1.80810 22.8 0.6307 41 -37.916 1.10 1.95375 32.3 0.5905 42 -697.095 0.21 43 120.544 9.57 1.51742 52.4 0.5564 44 -28.274 1.20 1.90525 35.0 0.5848 45 42.599 2.64 46 38.458 9.03 1.48749 70.2 0.5300 47 -58.875 43.00 Image plane ∞ Aspherical data Front page k = 1.99998e+00 A 4= 8.54220e-07 A 6= 1.96040e-09 A 8= 6.53684e-12 A10= 8.28841e-15 A12=-1.36205e-19 A14=-1.86406e-21 A16=-5.53996e-26 A 3=-1.50304e-06 A 5=-2.43022e-08 A 7=-1.24655e-10 A 9=-2.69778e-13 A11=-1.52238e-16 A13= 8.26224e-20 A15= 1.72204e-23 Page 3 k = 0.00000e+00 A 4=-5.45683e-09 A 6=-2.83251e-11 A 8=-1.17356e-14 A10= 3.19153e-18 A12=-3.11552e-22 A 3=-9.08712e-07 A 5= 5.49392e-10 A 7= 2.03602e-13 A 9=-4.51175e-17 A11 = -3.73605e-20 Page 8 k =-9.71744e-01 A 4= 5.95661e-07 A 6= 2.59768e-10 A 8=-2.69647e-14 A10=-6.70399e-16 A12=-7.74380e-20 A 3=-1.15291e-06 A 5=-3.08749e-09 A 7=-1.01360e-11 A 9= 1.67857e-14 A11 = 1.15114e-17 Page 18 k = 0.00000e+00 A 4= 5.80108e-09 A 6= 2.25557e-13 A 8= 1.46282e-14 A10= 5.06274e-18 A12= 2.78562e-21 A14=-1.22035e-23 A16= 6.65177e-27 A 3= 2.08017e-07 A 5= 2.66505e-10 A 7=-1.64439e-13 A 9=-4.83262e-16 A11= 1.41885e-19 A13=-3.86975e-23 A15=-1.89622e-26 Page 19 k = 1.82103e+00 A 4= 4.03264e-06 A 6=-5.32643e-08 A 8=-2.80290e-09 A10=-1.32797e-11 A12=-3.92886e-15 A 3=-1.75499e-06 A 5=-8.16887e-08 A 7= 1.78020e-08 A 9= 2.54221e-10 A11 = 3.64614e-13 Page 29 k = 1.44612e+00 A 4=-2.31215e-06 A 6=-1.06572e-07 A 8=-2.88533e-09 A10=-1.28541e-11 A12= 1.82513e-15 A14= 1.77979e-17 A16= 3.60991e-21 A 3=-1.66616e-07 A 5= 2.89521e-07 A 7= 2.21640e-08 A 9= 2.43506e-10 A11= 3.46624e-13 A13=-4.89946e-16 A15=-3.49460e-19 Various data Zoom ratio 7.60 Wide-angle, Medium, Telephoto Focal length 15.79 45.00 120.00 F-number 2.72 2.72 3.65 Half-angle (°): 43.14 18.21 7.03 Image height 14.80 14.80 14.80 Lens length 351.87 351.87 351.87 BF 43.00 43.00 43.00 d18 1.14 35.39 52.32 d23 3.15 5.45 7.99 d25 39.95 4.84 4.81 d28 13.20 15.68 0.80 d30 9.47 5.55 1.00 Lens group data Group starting plane focal length 1 1 46.03 2 19 -48.58 3 24 -84.93 4 26 -63.79 5 29 51.07 6 31 96.41 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd θgF 1* 5299.568 2.10 1.83481 42.7 0.5648 2 26.390 14.36 3* 58.658 1.50 1.80400 46.5 0.5577 4 34.583 17.21 5 -47.401 1.40 1.91650 31.6 0.5911 6 -151.774 0.13 7 185.556 9.07 1.80810 22.8 0.6307 8 -77.219 1.20 9 -736.255 7.89 1.59522 67.7 0.5442 10* -65.163 3.98 11 272.869 14.19 1.49700 81.5 0.5375 12 -41.172 1.70 1.95375 32.3 0.5905 13 -66.501 0.21 14 229.770 1.70 2.00100 29.1 0.5997 15 52.199 16.99 1.53775 74.7 0.5392 16 -66.894 0.20 17 1475.240 5.58 1.65412 39.7 0.5737 18 -86.882 (variable) 19* 64.766 0.93 1.85150 40.8 0.5695 20 29.448 3.62 21 378.242 0.85 1.76385 48.5 0.5589 22 18.644 5.33 1.85478 24.8 0.6122 23 192.908 0.72 24 -203.604 0.75 2.00100 29.1 0.5997 25 67.794 (Variable) 26 195.242 0.70 1.83481 42.7 0.5648 27 20.129 4.88 1.78880 28.4 0.6009 28 -237.204 1.74 29 -31.449 0.70 1.90525 35.0 0.5848 30* -421.412 (variable) 31 (aperture) ∞ 1.23 32* 163.720 2.99 1.51633 64.1 0.5353 33 -202.442 0.15 34 57.211 8.44 1.67270 32.1 0.5988 35 -37.304 1.10 1.95375 32.3 0.5905 36 -91.416 (variable) 37 116.199 1.00 1.96300 24.1 0.6212 38 32.690 10.95 1.60311 60.6 0.5415 39 -87.682 41.08 40 60.246 7.67 1.53775 74.7 0.5392 41 -59.558 5.50 42 -65.204 1.00 1.95375 32.3 0.5905 43 48.375 6.55 1.92286 18.9 0.6495 44 -76.368 1.96 45 54.589 7.71 1.53775 74.7 0.5392 46 -38.732 1.00 2.00100 29.1 0.5997 47 36.562 0.21 48 29.834 14.04 1.51823 58.9 0.5457 49 -26.006 1.00 2.00100 29.1 0.5997 50 -45.943 37.99 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-3.00133e-06 A 6=-4.71204e-07 A 8=-1.57470e-09 A10=-3.13880e-13 A12= 6.91900e-17 A14=-1.65891e-19 A16=-9.75519e-24 A 3= 2.05042e-05 A 5= 3.37014e-06 A 7= 3.53575e-08 A 9= 3.87228e-11 A11=-6.62646e-15 A13= 5.37587e-18 A15= 2.00120e-21 3rd page k = 0.00000e+00 A 4= 5.38076e-06 A 6= 8.40880e-07 A 8= 1.06309e-08 A10=-8.81100e-13 A12=-6.65923e-14 A14= 7.99567e-17 A16= 2.61196e-20 A 3=-1.21314e-05 A 5=-3.79326e-06 A 7=-1.18698e-07 A 9=-4.99386e-10 A11= 1.45840e-12 A13= 1.37723e-16 A15=-2.55421e-18 Page 10 k = 0.00000e+00 A 4= 5.55314e-07 A 6=-3.22665e-08 A 8= 7.86250e-11 A10= 1.00039e-12 A12=-1.68194e-16 A14=-2.74405e-19 A16= 4.69241e-23 A 3= 1.19903e-06 A 5= 2.29863e-07 A 7= 1.72919e-09 A 9=-1.70004e-11 A11=-2.31999e-14 A13= 1.92733e-17 A15=-1.60775e-21 Page 19 k = 0.00000e+00 A 4= 1.18567e-07 A 6= 1.22085e-09 A 8=-1.22302e-11 A10= 8.72663e-17 A12=-3.01996e-19 A14= 6.91730e-22 A16= 3.09204e-24 A 3=-2.28028e-07 A 5=-1.85118e-08 A 7= 4.56647e-11 A 9= 5.04436e-13 A11= 2.05552e-18 A13=-8.72532e-21 A15=-3.99022e-23 Page 30 k = 0.00000e+00 A 4=-7.03741e-08 A 6= 4.14639e-11 A 8= 1.27259e-13 A10= 5.56621e-15 A12= 1.73647e-17 A14=-2.88252e-19 A16=-2.69879e-21 A 3= 3.00352e-07 A 5=-7.77383e-10 A 7= 6.65859e-13 A 9=-6.10018e-14 A11= 3.09287e-18 A13=-2.52017e-18 A15= 5.64637e-20 Page 32 k = 0.00000e+00 A 4=-6.97696e-06 A 6=-7.89453e-07 A 8=-1.98584e-08 A10=-9.04060e-11 A12=-3.46036e-13 A14=-1.55281e-15 A16=-4.73404e-19 A 3= 2.08347e-06 A 5= 2.49198e-06 A 7= 1.55372e-07 A 9= 1.65304e-09 A11= 4.31418e-12 A13= 2.96113e-14 A15= 4.25677e-17 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.22 55.00 F-numbers: 2.77, 2.78, 3.62 Half-angle (°): 52.30 27.67 15.06 Image height 14.80 14.80 14.80 Lens length 320.41 320.41 320.41 BF 37.99 37.99 37.99 d18 1.30 29.65 41.79 d25 18.08 2.75 3.29 d30 14.60 12.08 2.75 d36 15.24 4.75 1.38 Lens group data Group starting plane focal length 1 1 25.62 2 19 -28.87 3 26 -47.87 4 31 50.19 5 37 79.49 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd θgF 1* 150.825 2.70 1.95375 32.3 0.5905 2 36.552 22.52 3* -178.762 2.10 2.00100 29.1 0.5997 4 -493.217 0.67 5 87.612 4.43 1.95906 17.5 0.6598 6 171.533 2.00 7 115.233 8.12 1.43875 94.7 0.5340 8* -171.116 10.68 9 132.722 2.00 1.85478 24.8 0.6122 10 51.577 16.06 1.43875 94.7 0.5340 11 -130.500 0.30 12 1010.998 10.30 1.43387 95.1 0.5373 13 -65.382 0.30 14 62.771 9.15 1.76385 48.5 0.5589 15 29465.068 (variable) 16* 1002.032 0.95 2.00330 28.3 0.5980 17 15.041 3.67 18 -106.804 0.95 2.00100 29.1 0.5997 19 77.594 6.97 1.80810 22.8 0.6307 20 -11.743 0.70 1.88300 40.8 0.5667 21 94.356 0.30 22 33.138 2.76 1.68893 31.1 0.6004 23 932.407 (variable) 24 -27.520 0.80 1.72916 54.7 0.5444 25 34.696 3.01 1.85478 24.8 0.6122 26 365.984 (variable) 27 (aperture) ∞ 1.00 28* 49.100 7.87 1.69930 51.1 0.5552 29 -49.239 0.20 30 126.217 6.74 1.60342 38.0 0.5835 31 -31.046 1.00 2.00100 29.1 0.5997 32 -328.829 (variable) 33 107.110 3.04 1.75520 27.5 0.6103 34 -149.555 1.74 35 47.264 0.90 1.89190 37.1 0.5780 36 19.727 4.58 1.51823 58.9 0.5457 37 38.455 0.48 38 28.638 8.30 1.43875 94.7 0.5340 39 -35.612 0.90 2.00100 29.1 0.5997 40 -443.466 1.30 41 42.483 6.26 1.48749 70.2 0.5300 42 -53.611 40.62 Image plane ∞ Aspherical data Front page k =-9.42852e-03 A 4= 1.18822e-06 A 6=-7.62250e-11 A 8=-8.12457e-13 A10= 1.32479e-15 A12=-9.61035e-19 A14= 3.32466e-22 A16=-4.45446e-26 3rd page k = 0.00000e+00 A 4=-2.19491e-07 A 6= 8.17815e-11 A 8= 9.24537e-14 A10= 2.92018e-16 A12=-8.95428e-19 A14= 8.68559e-22 A16=-2.71050e-25 Side 8 k = 8.70568e-02 A 4= 1.35150e-06 A 6= 4.58930e-11 A 8=-5.60834e-13 A10= 9.59917e-16 A12=-1.56533e-18 A14= 1.27198e-21 A16=-3.91482e-25 Page 16 k =-2.00040e+00 A 4= 1.32409e-05 A 6=-1.44002e-08 A 8=-2.59748e-09 A10= 1.03345e-10 A12=-1.75137e-12 A14= 1.38044e-14 A16=-4.13090e-17 Page 28 k = 9.36889e-01 A 4=-4.83818e-06 A 6= 2.20752e-09 A 8=-1.35068e-12 Various data Zoom ratio 17.29 Wide-angle, Medium, Telephoto Focal length 5.67 19.84 98.00 F-number 1.90 1.90 3.10 Half-angle (°): 44.14 15.49 3.21 Image height 5.50 5.50 5.50 Lens length 299.22 299.22 299.22 BF 40.62 40.62 40.62 d15 0.51 25.13 38.21 d23 33.61 4.34 5.81 d26 13.81 17.58 2.29 d32 54.92 55.80 56.54 Lens group data Group starting plane focal length 1 1 32.57 2 16 -13.75 3 24 -39.56 4 27 41.39 5 33 51.91 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd θgF 1 -155.668 2.80 1.74951 35.3 0.5818 2 155.754 2.37 3 167.765 5.49 1.95906 17.5 0.6598 4 438.170 3.53 5 935.463 11.25 1.60311 60.6 0.5415 6* -125.187 8.80 7 141.315 2.50 1.84666 23.8 0.6205 8 75.635 9.10 1.43875 94.7 0.5340 9 285.614 6.42 10 117.283 9.95 1.43387 95.1 0.5373 11 -337.833 0.20 12 70.181 9.97 1.59522 67.7 0.5442 13 478.746 (variable) 14* 176.809 0.95 1.75500 52.3 0.5474 15 17.092 7.42 16 -32.452 0.75 1.49700 81.5 0.5375 17 121.674 5.71 1.80000 29.8 0.6017 18 -24.131 0.89 19 -21.449 1.20 1.76385 48.5 0.5589 20* -146.711 (variable) 21 -171.662 4.35 1.80810 22.8 0.6307 22 -41.589 0.98 23 -36.738 1.10 1.90525 35.0 0.5848 24* -1031.815 (variable) 25* 64.115 8.46 1.64000 60.1 0.5370 26 -56.682 0.20 27 78.504 1.10 1.85478 24.8 0.6122 28 45.179 4.97 1.48749 70.2 0.5300 29 313.461 (variable) 30 (aperture) ∞ 1.98 31 331.046 4.72 1.48749 70.2 0.5300 32 -61.779 1.20 2.00100 29.1 0.5997 33 102.995 1.72 34 83.825 5.35 1.72825 28.5 0.6077 35 -96.628 43.76 36 75.816 6.85 1.43875 94.7 0.5340 37 -59.548 0.97 38 53.219 8.84 1.85896 22.7 0.6284 39 -41.598 0.90 2.00100 29.1 0.5997 40 49.358 2.38 41 51.365 7.92 1.48749 70.2 0.5300 42 -35.361 1.00 2.00100 29.1 0.5997 43 51.995 5.61 44 47.600 7.00 1.62004 36.3 0.5879 45 -88.746 41.71 Image plane ∞ Aspherical data Side 6 k =-1.25236e+01 A 4=-7.25004e-07 A 6= 2.49188e-10 A 8=-8.66607e-14 A10= 1.97057e-17 A12=-1.85117e-21 Page 14 k = 0.00000e+00 A 4=-1.04592e-06 A 6= 1.36523e-09 A 8=-3.75192e-11 A10= 1.35676e-13 A12=-2.04485e-16 Page 20 k = 3.85690e+01 A 4=-9.55664e-06 A 6=-4.53489e-09 A 8=-7.61531e-11 A10=3.08152e-13 A12=-9.70099e-16 Page 24 k = 0.00000e+00 A 4=-2.61673e-06 A 6=-7.42368e-08 A 8= 6.76194e-11 A10=-4.49156e-13 A12= 1.99668e-16 A14=-4.95653e-18 A16= 1.77155e-20 A 3= 2.52920e-06 A 5= 5.66243e-07 A 7= 3.54625e-09 A 9=-4.64656e-12 A11=-4.03972e-17 A13= 2.00067e-16 A15=-5.09038e-19 Page 25 k =-2.39273e+00 A 4=-2.38269e-06 A 6= 7.62403e-10 A 8= 2.43110e-12 A10=-9.37067e-15 A12= 9.96906e-18 Various data Zoom ratio 9.61 Wide-angle, Medium, Telephoto Focal length 26.01 78.61 249.99 F-number 2.74 2.74 3.67 Half-angle (°): 29.64, 10.66, 3.39 Image height 14.80 14.80 14.80 Lens length: 313.02 313.02 313.02 BF 41.71 41.71 41.71 d13 1.06 34.95 53.19 d20 54.40 3.12 0.36 d24 0.96 16.98 0.97 d29 4.24 5.62 6.14 Lens group data Group starting plane focal length 1 1 81.53 2 14 -19.18 3 21 -114.46 4 25 45.19 5 30 120.30 [Numerical Example 6] Unit: mm Surface data Face number rd nd νd θgF 1 ∞ 4.40 1.83481 42.7 0.5648 2 338.687 2.02 3 340.320 21.12 1.43387 95.1 0.5373 4 -1184.322 0.07 5 934.667 11.82 1.43387 95.1 0.5373 6 -1347.642 28.41 7 337.483 19.16 1.43387 95.1 0.5373 8 3081.712 0.15 9 438.915 7.96 1.43387 95.1 0.5373 10 830.239 0.15 11 469.553 14.81 1.43387 95.1 0.5373 12 -2186.790 0.09 13 161.121 16.97 1.43875 94.7 0.5340 14 322.247 (variable) 15* 461.639 2.00 2.00100 29.1 0.5997 16 77.852 9.14 17 -90.907 1.80 1.78880 28.4 0.6009 18 69.266 10.12 19 -66.058 1.81 1.80400 46.5 0.5577 20 -415.621 11.88 1.85896 22.7 0.6284 21 -79.575 0.12 22 128.421 14.73 1.78880 28.4 0.6009 23 -53.328 1.83 1.80400 46.5 0.5577 24 200.251 (variable) 25* 381.333 15.72 1.52841 76.5 0.5396 26 -106.008 2.60 1.85026 32.3 0.5929 27 -207.263 0.12 28 658.194 9.73 1.43875 94.7 0.5340 29 -192.655 (variable) 30* 450.673 6.62 1.59282 68.6 0.5458 31 -549.139 0.15 32 128.232 2.40 1.85025 30.1 0.5979 33 83.020 18.09 1.49700 81.5 0.5375 34 ∞ (Variable) 35 (aperture) ∞ 2.55 36 -115.498 1.63 1.72916 54.7 0.5444 37 -457.386 0.12 38 97.338 3.50 1.85896 22.7 0.6284 39 165.699 22.36 40 2454.844 8.71 1.59270 35.3 0.5933 41 -32.078 1.28 1.72916 54.6 0.5443 42 75.719 2.81 43 -295.624 9.05 1.53172 48.8 0.5662 44 -34.767 3.65 45 -37.622 1.13 1.74077 27.8 0.6095 46 -293.438 3.84 1.51742 52.4 0.5564 47 -49.214 3.20 48 -104.390 1.13 1.84850 43.8 0.5620 49 28.715 10.00 1.69895 30.1 0.5993 50 -57.793 7.70 51 -757.715 10.00 1.78590 44.2 0.5631 52 -21.797 1.15 1.78472 25.7 0.6160 53 -154.347 7.91 54 118.042 10.00 1.74000 28.3 0.6079 55* -45.099 5.08 56 -74.411 1.10 1.43700 95.1 0.5326 57 58.059 1.50 1.78880 28.4 0.6009 58 33.787 0.50 59 33.338 12.98 1.55200 70.7 0.5421 60 -20.953 1.20 1.95375 32.3 0.5905 61 18.042 15.00 1.60342 38.0 0.5835 62 -20.496 0.50 63 -20.295 4.47 1.85150 40.8 0.5695 64* -33.168 Image plane ∞ Aspherical data Page 15 K = 0.00000e+00 A 4= 7.22288e-07 A 6= 1.84105e-09 A 8= 1.06170e-12 A10=-1.36790e-14 A12=-2.26526e-17 A14= 1.76948e-19 A16= 3.39612e-23 A 5=-2.07624e-08 A 7=-7.38681e-11 A 9= 5.05429e-14 A11= 1.25468e-15 A13=-2.75498e-18 A15=-4.06819e-21 Page 25 K = 0.00000e+00 A 4= 3.98008e-09 A 6=-1.56598e-10 A 8=-3.80901e-13 A10= 1.04100e-15 A12= 5.60773e-19 A14=-9.67013e-23 A16=-7.27908e-27 A 3=-6.85365e-08 A 5=-3.65339e-10 A 7= 1.35962e-11 A 9=-8.71436e-15 A11=-3.56492e-17 A13=-1.29857e-21 A15= 1.48078e-24 Page 30 K = 0.00000e+00 A 4=-4.01788e-08 A 6=-2.72461e-10 A 8=-4.99905e-13 A10 = 1.05028e-16 A12 = 1.42261e-19 A14 = -1.92874e-23 A16 = -1.06164e-27 A3 = -6.78502e-09 A5 = 3.68410e-09 A7 = 1.45370e-11 A9 = 7.86512e-15 A11 = -7.69245e-18 A13 = -5.14619e-22 A15 = 2.73583e-25 Page 55 K = 0.00000e+00 A4 = 2.26712e-06 A6 = 3.77799e-08 A8 = 7.07722e-10 A10 = 2.94032e-12 A12 = -7.00715e-15 A14 = -1.42891e-17 A16 = -1.08686e-21 A5 = -1.74621e-07 A7 = -6.01002e-09 A9 = -5.93572e-11 A11 = -2.38914e-14 A13 = 4.73952e-16 A15 = 2.07277e-19 Page 64 K = 0.00000e+00 A4 = -7.86120e-06 A6 = -4.03202e-08 A8 = -5.37065e-09 A10 = -7.40380e-11 A12 = -4.53427e-13 A14 = -8.49643e-16 A16 = -1.67351e-19 A5 = -6.59676e-07 A7 = 2.94654e-08 A9 = 6.76290e-10 A11 = 6.61298e-12 A13 = 2.33892e-14 A15 = 1.83497e-17 Various data Zoom ratio 38.49 Wide angle, medium, telephoto Focal length 25.71 489.92 989.59 F-number 2.90 2.90 5.10 Half angle of view (°) 29.04 1.67 0.83 Image height 14.28 14.28 14.28 Overall lens length 762.92 762.92 762.92 BF 40.02 40.02 40.02 d14 5.33 151.36 159.57 d24 273.23 50.00 4.57 d29 47.72 33.49 20.04 d34 6.59 98.02 148.69 d64 40.02 40.02 40.02 Lens group data Group Starting surface Focal length 1 1 240.09 2 15 -35.17 3 25 188.46 4 30 208.28 5 35 968.46 Table 1 summarizes the values of the conditions of formulas (1) to (3) in Numerical Examples 1 to 6. Numerical Examples 1 to 6 satisfy all the conditions of formulas (1) to (3).

[0075] [Table 1]

[0076] [[ID=4q]][Imaging device] Figure 14 shows an imaging device equipped with the zoom lenses of Examples 1 to 6 as an imaging optical system. 101 is any one of the zoom lenses of Examples 1 to 6. 124 is a camera body. 125 is an imaging device configured by attaching the zoom lens 101 to the camera body 124. The zoom lens 101 is detachable from the camera body 124. However, the zoom lens 101 may be provided integrally with the camera body 124.

[0077] The zoom lens 101 has, in order from the object side to the image side, a first lens group F, a zoom section LZ, and an imaging lens group R. The first lens group F includes a focus group that moves during focusing. The zoom section LZ is an intermediate group that includes at least three or more movable lens groups. On the image side of the zoom section LZ are the aperture diaphragm SP, lens group R1, and lens group R2. The imaging device 125 also has an optical unit IE that can be inserted into and removed from the optical path between lens group R1 and lens group R2. By inserting the lens unit IE between lens group R1 and lens group R2, the range of the focal length of the entire zoom lens 101 system can be changed.

[0078] 114 and 115 are drive mechanisms that move the first lens group F and the lens group included in the zoom section LZ along the optical axis, respectively. 116 to 118 are motors that drive the drive mechanisms 114 and 115 and the aperture diaphragm SP, respectively. 119 to 121 are detection units that detect the position of the first lens group F and the lens group included in the zoom section LZ on the optical axis, and detect the aperture diameter of the aperture diaphragm SP, respectively.

[0079] In the camera body 124, 109 is a glass block such as an optical filter, and 110 is an image sensor that captures the subject image (i.e., the subject through the zoom lens 101) formed by the zoom lens 101. The image sensor 110 is composed of photoelectric conversion elements such as a CCD sensor or a CMOS sensor. 111 and 122 are the camera CPU, which is the processing unit in the camera body 124, and the lens CPU, which is the processing unit in the zoom lens 101, respectively.

[0080] The above embodiments include the following configuration.

[0081] (Composition 1) A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The zoom lens has five or more aspherical surfaces, The first lens group is composed of seven or more lenses, The first lens group includes a focus group that moves for focusing, When TL is the distance along the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0 <TL / fw≦53 A zoom lens characterized by satisfying the following conditions. (Configuration 2) When the focal length of the first lens group is f1, 1 ≤ f1 / fw ≤ 12 A zoom lens according to configuration 1, characterized by satisfying the following conditions. (Composition 3) At least one movable lens group included in the intermediate group has a negative refractive power, and when the focal length of the movable lens group with the strongest negative refractive power is f2 and the focal length of the first lens group is f1, -8≦f1 / f2<0 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditions. (Composition 4) A zoom lens according to any one of configurations 1 to 3, characterized in that the object-side surface of the first lens positioned closest to the object in the first lens group is aspherical. (Composition 5) The zoom lens according to configuration 4, characterized in that the object-side surface of the second lens adjacent to the first lens on the image side in the first lens group is aspherical. (Composition 6) The zoom lens according to configuration 5, characterized in that the aspherical surface of the second lens is an aspherical surface in which the sign of curvature does not reverse in the radial direction. (Configuration 7) The zoom lens according to any one of Configurations 1 to 6, wherein at least one moving lens group included in the intermediate group has an aspherical surface. (Configuration 8) The first lens group is a first sub-lens group having a negative refractive power, which is arranged on the object side of the focus group and does not move for focusing, and a second sub-lens group having a positive refractive power as the focus group, and a third sub-lens group having a positive refractive power, which is arranged on the image side of the focus group and does not move for focusing. The zoom lens according to any one of Configurations 1 to 7 is characterized by this. (Configuration 9) The zoom lens according to any one of Configurations 1 to 8, wherein the zoom lens does not form an intermediate image between the surface closest to the object side and the image surface. (Configuration 10) The plurality of lens groups are arranged in order from the object side to the image side, including the first lens group, the second lens group having a negative refractive power, the third lens group having a negative refractive power, and the fourth lens group having a positive refractive power, which constitute the intermediate group and move during zooming, and the fifth lens group as the rear lens group. The zoom lens according to any one of Configurations 1 to 9 is characterized by this. (Configuration 11) The plurality of lens groups are arranged in order from the object side to the image side, including the first lens group, the second lens group having a negative refractive power, the third lens group having a negative refractive power, the fourth lens group having a negative refractive power, and the fifth lens group having a positive refractive power, which constitute the intermediate group and move during zooming, and the sixth lens group as the rear lens group. The zoom lens according to any one of Configurations 1 to 9 is characterized by this. (Configuration 12) A zoom lens including a plurality of lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The zoom lens has five or more aspherical surfaces, The first lens group includes a focus group that moves for focusing, When TL is the distance along the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0 <TL / fw≦53 A zoom lens characterized by satisfying the following conditions. (Composition 13) A zoom lens described in any one of configurations 1 to 12, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

[0082] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of Symbols]

[0083] L1 First lens group L2 Second lens group L3 Third lens group L4 4th lens group L5 5th lens group L6 6th lens group SP aperture diaphragm I image plane

Claims

1. A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The aforementioned zoom lens has five or more aspherical surfaces, The first lens group is composed of seven or more lenses, The first lens group includes a focus group that moves for focusing, When TL is the distance along the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0<TL / fw≦53 A zoom lens characterized by satisfying the following conditions.

2. When the focal length of the first lens group is f1, 1 ≤ f1 / fw ≤ 12 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. At least one movable lens group included in the intermediate group has a negative refractive power, and when the focal length of the movable lens group with the strongest negative refractive power is f2 and the focal length of the first lens group is f1, -8≦f1 / f2<0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. The zoom lens according to claim 1, characterized in that the object-side surface of the first lens, which is positioned closest to the object in the first lens group, is aspherical.

5. The zoom lens according to claim 4, characterized in that the object-side surface of the second lens adjacent to the first lens on the image side in the first lens group is an aspherical surface.

6. The zoom lens according to claim 5, characterized in that the aspherical surface of the second lens is an aspherical surface in which the sign of curvature does not reverse in the radial direction.

7. The zoom lens according to claim 1, characterized in that at least one movable lens group included in the intermediate group has an aspherical surface.

8. The first lens group is, A first sub-lens group with negative refractive power, positioned closer to the object than the aforementioned focusing group and not moving for focusing, The second sub-lens group having positive refractive power as the focusing group, The zoom lens according to claim 1, further comprising a third sub-lens group having positive refractive power, which is positioned closer to the image side than the aforementioned focus group and does not move for focusing.

9. The zoom lens according to claim 1, characterized in that it does not form an intermediate image between the surface closest to the object and the image plane.

10. The zoom lens according to claim 1, characterized in that the plurality of lens groups are arranged in order from the object side to the image side, comprising a first lens group, a second lens group with negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group with negative refractive power and a fourth lens group with positive refractive power, and a fifth lens group as the rear lens group.

11. The zoom lens according to claim 1, characterized in that the plurality of lens groups are arranged in order from the object side to the image side, comprising a first lens group, a second lens group with negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group with negative refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, and a sixth lens group as the rear lens group.

12. A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The aforementioned zoom lens has five or more aspherical surfaces, The first lens group includes a focus group that moves for focusing, When TL is the distance along the optical axis from the object-side surface of the zoom lens to the image plane, and fw is the focal length of the zoom lens at the wide-angle end, 0<TL / fw≦53 A zoom lens characterized by satisfying the following conditions.

13. A zoom lens according to any one of claims 1 to 12, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

Images