ZOOM LENS AND IMAGE PICKUP APPARATUS

Abstract

A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power that does not move during zooming, an intermediate group including at least three lens units that move during zooming, and a final lens unit having positive refractive power that does not move during zooming. A distance between adjacent lens units changes during zooming. The intermediate group includes at least one lens unit having negative refractive power. A lens unit having negative refractive power and closest to an object among the at least one lens unit having negative refractive power includes at least one negative lens. Predetermined inequalities are satisfied.

Description

BACKGROUND

Technical Field

The present disclosure relates to a zoom lens for imaging.

Description of Related Art

As a positive lead type zoom lens in which a lens unit having positive refractive power is disposed closest to the object, Japanese Patent Laid-Open Nos. 2019-039945 and 2021-032925 disclose zoom lenses including five or more lens units. Japanese Patent Laid-Open No. 2019-039945 discloses a zoom lens having a zoom ratio of about 23 times, and including, in order from the object side to the image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having negative refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having positive refractive power. Japanese Patent Laid-Open No. 2021-032925 discloses a zoom lens having a zoom ratio of about 10 times, and including, in order from the object side to the image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having positive refractive power.

SUMMARY

A zoom lens according to one aspect of the disclosure includes, in order from an object side to an image side, a first lens unit having positive refractive power that does not move during zooming, an intermediate group including at least three lens units that move during zooming, and a final lens unit having positive refractive power that does not move during zooming. A distance between adjacent lens units changes during zooming. The intermediate group includes at least one lens unit having negative refractive power. A lens unit having negative refractive power and closest to an object among the at least one lens unit having negative refractive power includes at least one negative lens. The following inequalities are satisfied:

$2.02\le \mathrm{nn}\le 2.3$ $20.\le \mathrm{vn}\le 40.$ $1.5\le f1/\mathrm{fw}\le 7.7$

where nn is a refractive index for d-line of a negative lens closest to the object among the at least one negative lens, vn is an Abbe number based on the d-line of the negative lens closest to the object, fl is a focal length of the first lens unit, and fw is a focal length of the zoom lens at a wide-angle end. An image pickup apparatus having the above zoom lens also constitutes another aspect of the disclosure.

Further features of various embodiments of the disclosure will become apparent from the following description of embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a sectional view of a zoom lens according to Example 1 at a wide-angle end in an in-focus state at infinity.

FIG. 2A illustrates an aberration diagram of the zoom lens according to Example 1 at a wide-angle end in an in-focus state at infinity, and FIG. 2B illustrates an aberration diagram of the zoom lens according to Example 1 at a telephoto end in an in-focus state at infinity.

FIG. 3 illustrates a sectional view of a zoom lens according to Example 2 at a wide-angle end in an in-focus state at infinity.

FIG. 4A illustrates an aberration diagram of the zoom lens according to Example 2 at a wide-angle end in an in-focus state at infinity, and FIG. 4B illustrates an aberration diagram of the zoom lens according to Example 2 at a telephoto end in an in-focus state at infinity.

FIG. 5 illustrates a sectional view of a zoom lens according to Example 3 at a wide-angle end in an in-focus state at infinity.

FIG. 6A is an aberration diagram of the zoom lens according to Example 3 at a wide-angle end in an in-focus state at infinity, and FIG. 6B is an aberration diagram of the zoom lens according to Example 3 at a telephoto end in an in-focus state at infinity.

FIG. 7 is a sectional view of a zoom lens according to Example 4 at a wide-angle end in an in-focus state at infinity.

FIG. 8A is an aberration diagram of the zoom lens according to Example 4 at a wide-angle end in an in-focus state at infinity, and FIG. 8B is an aberration diagram of the zoom lens according to Example 4 at a telephoto end in an in-focus state at infinity.

FIG. 9 is a sectional view of a zoom lens according to Example 5 at a wide-angle end in an in-focus state at infinity.

FIG. 10A is an aberration diagram of the zoom lens according to Example 1 at a wide-angle end in an in-focus state at infinity, and FIG. 10B is an aberration diagram of the zoom lens according to Example 1 at a telephoto end in an in-focus state at infinity.

FIG. 11 is a sectional view of a zoom lens according to Example 6 at a wide-angle end in an in-focus state at infinity.

FIG. 12A is an aberration diagram of the zoom lens according to Example 6 at a wide-angle end in an in-focus state at infinity, and FIG. 12B is an aberration diagram of the zoom lens according to Example 6 at a telephoto end in an in-focus state at infinity.

FIG. 13 illustrates an image pickup apparatus having the zoom lens according to any one of Examples 1 to 6.

DETAILED DESCRIPTION

Referring now to the accompanying drawings, a description will be given of examples according to the disclosure. Prior to a detailed description according to Examples 1 to 6, matters common to each example will be described.

In a zoom lens, a lens unit is a group of one or more lenses that move together during magnification variation (zooming) between a wide-angle end and a telephoto end. That is, a distance between adjacent lens units changes during zooming. The lens unit may include an aperture stop (diaphragm). The wide-angle end and the telephoto end respectively indicate the zoom states of a maximum angle of view (shortest focal length) and a minimum angle of view (longest focal length) when the lens unit that moves during zooming is located at both ends of a mechanically or controllably movable range on the optical axis.

The zoom lens according to each example is used for cinema cameras, broadcasting cameras, video cameras, surveillance cameras, digital still cameras, and film-based cameras.

The zoom lens according to each example includes, in order from the object side to the image side, a first lens unit having positive refractive power, an intermediate group, and a final lens unit having positive refractive power. The first lens unit does not move during zooming. The intermediate group includes at least three lens units that move during zooming. The final lens unit does not move during zooming. The intermediate group includes at least one lens unit having negative refractive power. A lens unit having negative refractive power and closest to the object among the at least one lens unit having negative refractive power (referred to as an object-side negative lens unit hereinafter) V includes at least one negative lens.

The following inequalities (1) to (3) may be satisfied:

$\begin{array}{cc}2.02\le \mathrm{nn}\le 2.3& \left(1\right)\end{array}$ $\begin{array}{cc}20.\le \mathrm{vn}\le 40.& \left(2\right)\end{array}$ $\begin{array}{cc}1.5\le f1/\mathrm{fw}\le 7.7& \left(3\right)\end{array}$

where nn is a refractive index for the d-line of the negative lens closest to the object among the at least one negative lens included in the object-side negative lens unit V, vn is an Abbe number based on the d-line of the negative lens closest to the object, fl is a focal length of the first lens unit, and fw is a focal length of the zoom lens at the wide-angle end.

The Abbe number v based on the d-line is expressed as:

$v=\left(\mathrm{Nd}-1\right)/\left(\mathrm{NF}-\mathrm{NC}\right)$

where Nd, NF, and NC are refractive indices for the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) in the Fraunhofer line, respectively.

Inequalities (1) and (2) define proper characteristics of the glass material of the negative lens closest to the object among the object-side negative lens unit V. Using glass materials that satisfy inequalities (1) and (2) can achieve a refractive power arrangement that is beneficial to a wide angle and high magnification, and suppress various aberrations. In a case where nn becomes higher than the upper limit of inequality (1), the dispersion becomes too large for currently available glass materials, and it becomes difficult to correct chromatic aberration. In a case where nn becomes lower than the lower limit of inequality (1), it becomes difficult to achieve a wide angle and high magnification and to suppress various aberrations. In a case where nn becomes higher than the upper limit of inequality (2), the refractive index becomes too low for currently available glass materials, and it becomes difficult to achieve a wide angle and high magnification and to suppress various aberrations. In a case where nn becomes lower below the lower limit of inequality (2), the dispersion becomes too large, and it becomes difficult to correct chromatic aberration.

Inequality (3) defines a proper relationship between the first lens unit and the focal length at the wide-angle end of the zoom lens. Satisfying inequality (1) can achieve both the size reduction and high optical performance of the zoom lens. In a case where fl/fw becomes higher than the upper limit of inequality (1), the refractive power of the first lens unit decreases, the lens diameter of the first lens unit increases, and it becomes difficult to reduce the size of the zoom lens. In a case where fl/fw becomes lower than the lower limit of inequality (1), the refractive power of the first lens unit increases, the curvature of the lenses in the first lens unit increases, and it becomes difficult to achieve high optical performance.

Inequalities (1) to (3) may be replaced with inequalities (1a) to (3a) below:

$\begin{array}{cc}2.03\le \mathrm{nn}\le 2\text{.25}& \left(1a\right)\end{array}$ $\begin{array}{cc}22.\le \mathrm{vn}\le 35.& \left(2a\right)\end{array}$ $\begin{array}{cc}1.7\le f1/\mathrm{fw}\le 7.5& \left(3a\right)\end{array}$

Inequalities (1) to (3) may be replaced with inequalities (1b) to (3b) below:

$\begin{array}{cc}2.04\le \mathrm{nn}\le 2\text{.20}& \left(1b\right)\end{array}$ $\begin{array}{cc}24.\le \mathrm{vn}\le 30.& \left(2b\right)\end{array}$ $\begin{array}{cc}1.9\le f1/\mathrm{fw}\le 4.0& \left(3b\right)\end{array}$

Satisfying the above configurations and conditions can achieve a zoom lens that has a wide angle of view, a high zoom ratio, and high optical performance over the entire zoom range.

The zoom lens according to each example may satisfy at least one of the following inequalities (4) to (9) and configurations:

$\begin{array}{cc}0.7\le \mathrm{fn}/\mathrm{fV}\le 2.& \left(4\right)\end{array}$ $\begin{array}{cc}0.63\le \theta n+0.00162\times \mathrm{vn}\le 0.7& \left(5\right)\end{array}$ $\begin{array}{cc}60\le v\le 100& \left(6\right)\end{array}$ $\begin{array}{cc}-0.004\le \left(\theta p_{\mathrm{ave}}-\theta n_{\mathrm{ave}}\right)/\left({\mathrm{vp}}_{\mathrm{ave}}-{\mathrm{vn}}_{\mathrm{ave}}\right)<0.& \left(7\right)\end{array}$ $\begin{array}{cc}-5.5\le \mathrm{fV}/\mathrm{fw}\le -0.3& \left(8\right)\end{array}$ $\begin{array}{cc}0.2\le \mathrm{fw}/\mathrm{IS}\le 2.2& \left(9\right)\end{array}$

In inequalities (4) to (9), fn is a focal length of the negative lens closest to the object in the object-side negative lens unit V, fV is a focal length of the lens unit V, and θn is a partial dispersion ratio of the negative lens closest to the object in the lens unit V for the g-line and F-line. v is an Abbe number based on the d-line as a reference of at least one negative lens included in the object-side negative lens unit V. θp_ave and vp_ave are an average value of partial dispersion ratios for the g-line and F-line of all positive lenses included in the object-side negative lens unit V, and an average value of Abbe numbers based on the d-line as the reference of all positive lenses included in the object-side negative lens unit V, respectively. The partial dispersion ratio θ at the g-line and F-line is expressed as follows:

$\theta =\left(\mathrm{Ng}-\mathrm{NF}\right)/\left(\mathrm{NF}-\mathrm{NC}\right)$

where Ng is a refractive index for the g-line (435.8 nm) in the Fraunhofer line.

θn_ave and vn_ave are an average value of partial dispersion ratios for the g-line and F-line of all negative lenses included in the object-side negative lens unit V, and an average value of Abbe numbers for the d-line as the reference of all negative lenses included in the object-side negative lens unit V, respectively. IS is a diagonal length of the effective imaging surface of the image sensor configured to perform imaging through the zoom lens. The effective imaging surface is an area of the imaging surface of the image sensor that includes pixels that output signals that are used to generate image data.

Inequality (4) defines a proper relationship between the focal length of the negative lens closest to the object in the object-side negative lens unit V and the focal length of the object-side negative lens unit V. Satisfying inequality (4) can achieve a wide angle and suppress various aberrations. In a case where fn/fV becomes higher than the upper limit of inequality (4), the refractive power of the negative lens closest to the object decreases, and it becomes difficult to achieve a wide angle. In a case where fn/fV becomes lower than the lower limit of inequality (4), the refractive power of the negative lens closest to the object increases, and it becomes difficult to suppress various aberrations.

Inequality (5) illustrates a proper characteristic of the glass material of the negative lens closest to the object in the object-side negative lens unit V. Satisfying inequality (5) can suppress longitudinal and lateral chromatic aberrations. In a case where θn+0.00162×vn becomes higher than the upper limit of inequality (5), there is no existing glass material. In a case where θn+0.00162×vn becomes lower than the lower limit of inequality (5), the correction of chromatic aberration becomes insufficient.

Inequality (6) defines a proper characteristic of the glass material of the negative lens included in the object-side negative lens unit V. Satisfying inequality (6) can satisfactorily correct longitudinal chromatic aberration at the telephoto end. In a case where v becomes higher than the upper limit of inequality (6), there is no existing glass material. In a case where v becomes lower than the lower limit of inequality (6), it becomes difficult to satisfactorily correct the longitudinal chromatic aberration at the telephoto end.

Inequality (7) defines a proper achromatic condition for the object-side negative lens unit V. Satisfying inequality (7) can provide an achromatic effect that can satisfactorily correct longitudinal and lateral chromatic aberrations. In a case where (θp_ave−θn_ave)/(vp_ave−vn_ave) becomes higher than the upper limit of inequality (7), it becomes difficult to effectively correct longitudinal chromatic aberration. In a case where (θp_ave−θn_ave)/(vp_ave−vn_ave) becomes lower than the lower limit of inequality (7), it becomes difficult to effectively correct lateral chromatic aberration at the wide-angle side and the fluctuation of lateral chromatic aberration due to zooming.

Inequality (8) illustrates a proper relationship between the focal length of the object-side negative lens unit V and the focal length at the wide-angle end of the zoom lens. Satisfying inequality (8) can achieve a high zoom ratio and suppress various aberrations. In a case where fV/fw becomes higher than the upper limit of inequality (8), the refractive power of the object-side negative lens unit V becomes too weak, and the zoom lens becomes too large to achieve a high zoom ratio. In a case where fV/fw becomes lower than the lower limit of inequality (8), the refractive power of the object-side negative lens unit V becomes too strong, and it becomes difficult to suppress various aberrations.

Inequality (9) defines a proper relationship between the focal length at the wide-angle end of the zoom lens and the diagonal length of the effective imaging surface of the image sensor when the zoom lens according to each example is used for the image pickup apparatus. Satisfying inequality (9) can achieve a proper specification according to the image pickup apparatus. In a case where fw/IS becomes lower than the lower limit of inequality (9), the zoom lens becomes excessively wide-angle, and it becomes difficult to correct off-axis aberrations such as distortion and lateral chromatic aberration. In a case where fw/IS becomes higher than the upper limit of inequality (9), the zoom lens becomes excessively telephoto, and it becomes difficult to correct longitudinal chromatic aberration and other aberrations at the telephoto end.

Inequalities (4) to (9) may be replaced with inequalities (4a) to (9a) below:

$\begin{array}{cc}0.8\le \mathrm{fn}/\mathrm{fV}\le 1.8& \left(4a\right)\end{array}$ $\begin{array}{cc}0.63\le \theta n+0.00162\times \mathrm{vn}\le 0.68& \left(5a\right)\end{array}$ $\begin{array}{cc}62\le v\le 98& \left(6a\right)\end{array}$ $\begin{array}{cc}-0.0038\le \left(\theta p_{\mathrm{ave}}-\theta n_{\mathrm{ave}}\right)/\left({\mathrm{vp}}_{\mathrm{ave}}-{\mathrm{vn}}_{\mathrm{ave}}\right)\le -0.0005& \left(7a\right)\end{array}$ $\begin{array}{cc}-5.2\le \mathrm{fV}/\mathrm{fw}\le -0.5& \left(8a\right)\end{array}$ $\begin{array}{cc}0.3\le \mathrm{fw}/\mathrm{IS}\le 2.1& \left(9a\right)\end{array}$

Inequalities (4) to (9) may be replaced with inequalities (4b) to (9b) below:

$\begin{array}{cc}0.9\le \mathrm{fn}/\mathrm{fV}\le 1.6& \left(4b\right)\end{array}$ $\begin{array}{cc}0.64\le \theta n+0.00162\times \mathrm{vn}\le 0.66& \left(5b\right)\end{array}$ $\begin{array}{cc}64\le v\le 96& \left(6b\right)\end{array}$ $\begin{array}{cc}-0.0035\le \left(\theta p_{\mathrm{ave}}-\theta n_{\mathrm{ave}}\right)/\left({\mathrm{vp}}_{\mathrm{ave}}-{\mathrm{vn}}_{\mathrm{ave}}\right)\le -0.001& \left(7b\right)\end{array}$ $\begin{array}{cc}-4.9\le \mathrm{fV}/\mathrm{fw}\le -0.7& \left(8b\right)\end{array}$ $\begin{array}{cc}0.35\le \mathrm{fw}/\mathrm{IS}\le 2.& \left(9b\right)\end{array}$

In each example, the negative lens closest to the object among at least one negative lens in the object-side negative lens unit V may be an aspheric lens. This configuration can easily suppress the fluctuation in distortion on the wide-angle side.

In each example, the object-side negative lens unit V may include at least four lenses. This configuration can easily suppress various aberrations, particularly fluctuations in off-axis aberrations due to zooming on the wide-angle side.

In each example, a part of the first lens unit (a focus subgroup) may move for focusing. This configuration can maintain a moving amount of the focus subgroup constant over the entire zoom range, and prevent fluctuations in zoom magnification along with focusing on an object at a close distance.

The zoom lens according to each example will be described in detail below. After the description according to Example 6, numerical examples 1 to 6 corresponding to Examples 1 to 6, respectively, will be illustrated.

Example 1

FIG. 1 illustrates a section of a zoom lens 1a according to Example 1 (numerical example 1) at a wide-angle end in a state where the lens is in focus on an object at infinity (hereinafter referred to as “in an in-focus state at infinity”). In this sectional view and in the sectional views of other examples described later, a left side is an object side (front side) and a right side is an image side (rear side). OA represents an optical axis and I represents an image plane. An imaging surface (light receiving surface) of an image sensor such as a CCD sensor or a CMOS sensor or a film surface (photosensitive surface) of a silver film is disposed on the image plane I.

The zoom lens 1a consists of, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, a fourth lens unit L4 having positive refractive power, a fifth lens unit L5 having positive refractive power, an aperture stop SP, and a sixth lens unit L6 having positive refractive power. The first lens unit L1 does not move during zooming, while the second, third, fourth and fifth lens units L2, L3, L4 and L5, which constitute the intermediate group, move during zooming. Arrows in FIG. 1 indicate moving loci of the lens units that move during zooming from the wide-angle end to the telephoto end, and this is similarly applicable to the sectional views of other examples described later. The sixth lens unit L6 is the final lens unit for imaging and does not move during zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, and a third sub-lens unit L13 having positive refractive power. The second sub-lens unit L12 is a focus subgroup that moves to the image side during focusing from infinity to a close distance, as indicated by an arrow (FOCUS) in FIG. 1.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes four lenses (two of which form a cemented lens), and the negative lens closest to the object is an aspherical lens. An optical unit such as an extender lens for focal length conversion may be inserted into the sixth lens unit L6.

FIG. 2A illustrates a longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens 1a at the wide-angle end in an in-focus state at infinity. FIG. 2B illustrates a longitudinal aberration of the zoom lens 1a at a telephoto end in an in-focus state at infinity. A solid line, alternate long and two short dashes line, alternate long and short dash line, and dashed line in the spherical aberration diagram illustrate spherical aberration amounts for the d-line, g-line, C-line, and F-line, respectively. Solid and dashed lines in the astigmatism diagram illustrate astigmatism amounts on a sagittal image plane (ΔS) and a meridional image plane (ΔM), respectively. The distortion diagram illustrates a distortion amount for the d-line. An alternate long and two short dashes line, alternate long and short dash line, and dashed line in the chromatic aberration diagram indicate lateral chromatic aberration amounts for the g-line, C-line, and F-line, respectively. The astigmatism and lateral chromatic aberration illustrate aberration amounts when the ray passing through the center of the light beam at the position of the aperture stop SP is set as a principal ray. ω is a paraxial half angle of view (°), and Fno is an F-number. The spherical aberration diagram is illustrated on a scale of 0.4 mm, the astigmatism diagram is illustrated on a scale of 0.4 mm, the distortion diagram is illustrated on a scale of 10%, and the chromatic aberration diagram is illustrated on a scale of 0.1 mm.

A description regarding the sectional view and longitudinal aberration diagram of the zoom lens according to this example is similarly applicable to the following examples.

Example 2

FIG. 3 illustrates a section of a zoom lens 1b according to Example 2 (numerical example 2) at a wide-angle end in an in-focus state at infinity.

The zoom lens 1b consists of, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, an aperture stop SP, a fourth lens unit L4 having positive refractive power, and a fifth lens unit L5 having positive refractive power. The first lens unit L1 does not move during zooming, while the second lens unit L2, the third lens unit L3, and the fourth lens unit L4, which constitute the intermediate group, do move during zooming. The fifth lens unit L5 is the final lens unit for imaging, and does not move during zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, and a third sub-lens unit L13 having positive refractive power. The second sub-lens unit L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to a close distance, as indicated by an arrow (FOCUS) in FIG. 3.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes four lenses (three of which form one cemented lens), and the negative lens closest to the object is an aspheric lens. The fourth lens unit L4 moves together with the aperture stop SP during zooming. An optical unit such as an extender lens may be inserted into the fifth lens unit L5.

FIG. 4A illustrates a longitudinal aberration of zoom lens 1b at a wide-angle end in an in-focus state at infinity and, and FIG. 4B illustrates a longitudinal aberration of zoom lens 1b at a telephoto end in an in-focus state at infinity.

Example 3

FIG. 5 illustrates a section of a zoom lens 1c according to Example 3 (numerical example 3) at a wide-angle end in an in-focus state at infinity.

The zoom lens 1c consists of, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, a fourth lens unit L4 having positive refractive power, a fifth lens unit L5 having positive refractive power, an aperture stop SP, and a sixth lens unit L6 having positive refractive power. The first lens unit L1 does not move during zooming, while the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5, which constitute the intermediate group, move during zooming. The sixth lens unit L6 is the final lens unit for imaging, and does not move for zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, a third sub-lens unit L13 having positive refractive power, a fourth sub-lens unit L14 having positive refractive power, and a fifth sub-lens unit L15 having positive refractive power. The second sub-lens unit L12, the fourth sub-lens unit L14, and the fifth sub-lens unit L15 are focus subgroups that move on different loci when focusing from infinity to a close distance, as illustrated by an arrow (FOCUS) in FIG. 5.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes four lenses (two of which form a cemented lens), and the negative lens closest to the object is an aspheric lens. An optical unit such as an extender lens may be inserted into the sixth lens unit L6.

FIG. 6A illustrates a longitudinal aberration of the zoom lens 1c at a wide-angle end in an in-focus state at infinity, and FIG. 6B illustrates a longitudinal aberration of the zoom lens 1b at a telephoto end in an in-focus state at infinity.

Example 4

FIG. 7 illustrates a section of the zoom lens 1d according to Example 4 (numerical example 4) at a wide-angle end in an in-focus state at infinity.

The zoom lens 1d consists of, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, an aperture stop SP, a fourth lens unit L4 having positive refractive power, and a fifth lens unit L5 having positive refractive power. The first lens unit L1 does not move during zooming, while the second lens unit L2, the third lens unit L3, and the fourth lens unit L4 which constitute the intermediate group, move during zooming. The fifth lens unit L5 is the final lens unit for imaging, and does not move during zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, and a third sub-lens unit L13 having positive refractive power. The second sub-lens unit L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to a close distance, as indicated by an arrow (FOCUS) in FIG. 7.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes four lenses (two of which form a cemented lens), and the negative lens closest to the object is an aspheric lens. In this example, the second lens unit L2 corresponds to the object-side negative lens unit V. The fourth lens unit L4 moves integrally with the aperture stop SP during zooming. An optical unit such as an extender lens may be inserted into the fifth lens unit L5.

FIG. 8A illustrates a longitudinal aberration of the zoom lens 1d at a wide-angle end in an in-focus state at infinity and, and FIG. 8B illustrates a longitudinal aberration of the zoom lens 1d at a telephoto end in an in-focus state at infinity.

Example 5

FIG. 9 illustrates a section of a zoom lens 1e according to Example 5 (numerical example 5) at a wide-angle end in an in-focus state at infinity.

The zoom lens 1e includes, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, an aperture stop SP, a fourth lens unit L4 having positive refractive power, a fifth lens unit L5 having positive refractive power, and a sixth lens unit having positive refractive power. G is an optical block such as a prism or an optical filter.

The first lens unit L1 does not move during zooming, and the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5, which constitute the intermediate groups, do move during zooming. The sixth lens unit L6 is the final lens unit for imaging, and does not move during zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, and a third sub-lens unit L13 having positive refractive power. The second sub-lens unit L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to a close distance, as indicated by an arrow (FOCUS) in FIG. 9.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes five lenses (two of which form one cemented lens), and the negative lens closest to the object is an aspheric lens. The fourth lens unit L4 moves together with the aperture stop SP during zooming. An optical unit such as an extender lens may be inserted into the sixth lens unit L6.

FIG. 10A illustrates a longitudinal aberration of the zoom lens 1e at a wide-angle end in an in-focus state at infinity, and FIG. 10B illustrates a longitudinal aberration of the zoom lens 1e at a telephoto end in an in-focus state at infinity.

Example 6

FIG. 11 illustrates a section of a zoom lens 1f according to Example 6 (numerical example 6) at a wide-angle end in an in-focus state at infinity.

The zoom lens 1f includes, in order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having negative refractive power, a fourth lens unit L4 having positive refractive power, an aperture stop SP, and a fifth lens unit L5 having positive refractive power. G is an optical block such as a prism or an optical filter.

The first lens unit L1 does not move during zooming, and the second lens unit L2, the third lens unit L3, and the fourth lens unit L4, which constitute the intermediate group, move during zooming. The fifth lens unit L5 is the final lens unit for imaging and does not move during zooming.

The first lens unit L1 includes, in order from the object side to the image side, a first sub-lens unit L11 having negative refractive power, a second sub-lens unit L12 having positive refractive power, and a third sub-lens unit L13 having positive refractive power. The second sub-lens unit L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to a close distance, as indicated by an arrow (FOCUS) in FIG. 11.

The second lens unit L2 corresponds to the object-side negative lens unit V, and moves to the image side as a variator during zooming from the wide-angle end to the telephoto end. The second lens unit L2 includes five lenses (two of which form one cemented lens), and the negative lens closest to the object is an aspheric lens. An optical unit such as an extender lens may be inserted into the fifth lens unit L5.

Numerical examples 1 to 6 will be illustrated below. In each numerical example, a surface number i is the order of a surface counted from the object side, r represents a radius of curvature of an i-th surface (mm), and d represents a distance on the optical axis between i-th and (i+1)-th surfaces (mm). A portion where the distance d is (variable) indicates a distance that changes during zooming and accord with a focal length illustrated in a separate table.

nd is a refractive index (absolute refractive index at 1 atmosphere) for the d-line of the optical material between i-th and (i+1)-th surfaces. vd is an Abbe number based on the d-line of the optical material between i-th and (i+1)-th surfaces. θgF is a partial dispersion ratio for the g-line and F-line of the optical material between i-th and (i+1)-th surfaces.

In addition to a specification, such as a focal length and an F-number, of the zoom lens, each numerical example illustrates a half angle of view (°) of the zoom lens. BF represents a back focus, which is an air equivalent length from a (final) surface closest to the image plane of the zoom lens to the image surface. An overall lens length is a distance from a (foremost) surface closest to the object of a zoom lens to the final surface plus the back focus. WIDE, MIDDLE, and TELE represent a wide-angle end, an intermediate zoom position, and a telephoto end, respectively.

An asterisk “*” next to a surface number means that the surface has an aspheric shape. The aspheric shape is expressed by the following equation:

$x=\frac{H^2/R}{1+\sqrt{1-\left(1+k\right){\left(H/R\right)}^2}}+A4·H^4+A6H^6+A8H^8+A10H^{10}+A12H^{12}+A14H^{14}+A16H^{16}+A3H^3+A5H^5+A7H^7+A9H^9+A11H^{11}+A13H^{13}+A15H^{15}$

where x is a displacement amount from a surface vertex in the optical axis direction, His a height from the optical axis in a direction perpendicular to the optical axis, a light traveling direction is positive, R is a paraxial radius of curvature, k is a conic constant, and A3 to A16 are aspheric coefficients.

In the conic constant and aspheric coefficients, “e-X” means “×10^−X.”

The lens unit data illustrates a focal length of each lens unit. Table 1 summarizes values of inequalities (1) to (9) for each numerical example. The zoom lens according to each numerical example satisfies all of inequalities (1) to (9).

Numerical Example 1

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1*	∞	2.80	1.80100	35.0	0.5864
2	45.306	26.83
3	−76.888	2.00	1.64000	60.1	0.5370
4	130.776	1.31
5	139.162	8.49	1.95906	17.5	0.6598
6	−402.098	1.19
7	646.982	11.36	1.59522	67.7	0.5442
8*	−82.754	5.15
9	514.992	9.73	1.43875	94.7	0.5340
10	−98.376	2.00	1.84666	23.8	0.6205
11	−275.863	0.20
12	194.597	7.32	1.49700	81.5	0.5375
13	−296.206	0.20
14	155.285	2.00	1.80518	25.4	0.6161
15	58.335	17.85	1.43875	94.7	0.5340
16	−162.863	0.20
17	131.230	10.48	1.76385	48.5	0.5589
18	−154.452	(Variable)
19*	117.501	1.24	2.05090	26.9	0.6054
20	23.330	7.71
21	−33.594	0.85	1.49700	81.5	0.5375
22	35.319	5.34	1.85478	24.8	0.6122
23	−49.243	1.51
24	−28.530	1.00	1.88300	40.8	0.5667
25	−55.566	(Variable)
26	−34.067	0.80	1.59522	67.7	0.5442
27	73.984	2.39	1.85896	22.7	0.6284
28	344.383	(Variable)
29*	73.879	5.01	1.89190	37.1	0.5780
30	−161.379	(Variable)
31	86.610	1.10	2.00069	25.5	0.6136
32	40.331	7.35	1.55200	70.7	0.5421
33	−124.178	(Variable)
34 (SP)	∞	1.00
35	126.863	5.96	1.48749	70.2	0.5300
36	−61.210	0.25
37	−184.110	5.67	1.76182	26.5	0.6136
38	−32.960	1.10	2.00100	29.1	0.5997
39	533.450	41.06
40	−677.771	5.71	1.48749	70.2	0.5300
41	−37.548	2.04
42	49.952	7.10	1.80810	22.8	0.6307
43	−40.270	0.90	2.00100	29.1	0.5997
44	36.481	1.73
45	32.405	11.06	1.43875	94.7	0.5340
46	−23.422	1.00	1.88300	40.8	0.5667
47	191.906	0.50
48	52.888	7.16	1.48749	70.2	0.5300
49	−44.634	44.77
Image Plane	∞
ASPHERIC DATA
1st Surface
K = 0.00000e+00	A4 = 5.17853e−07	A6 = 5.27289e−10	A8 = −6.93652e−13
A10 = 4.72801e−16	A12 = −1.88957e−19	A14 = 4.12626e−23	A16 = −3.82327e−27
8th Surface
K = 0.00000e+00	A4 = 5.70451e−07	A6 = 8.31297e−11	A8 = −8.23396e−14
A10 = 1.96459e−16	A12 = −2.97759e−19	A14 = 2.00949e−22	A16 = −5.03199e−26
19th Surface
K = 0.00000e+00	A4 = 3.75208e−06	A6 = −2.79727e−09	A8 = 1.59700e−11
A10 = −7.27063e−14	A12 = 1.95147e−16
29th Surface
K = 0.00000e+00	A4 = −1.64984e−06	A6 = 5.45725e−10	A8 = −3.16916e−13
VARIOUS DATA
ZOOM RATIO 8.22
	WIDE	MIDDLE	TELE
Focal Length	15.08	58.04	124.02
Fno	2.72	2.72	3.77
Half Angle of View (°)	44.46	14.30	6.81
Image Height	14.80	14.80	14.80
Overall Lens Length	340.03	340.03	340.03
BF	44.77	44.77	44.77
d18	0.99	38.95	48.44
d25	33.07	2.45	2.31
d28	17.89	15.68	1.16
d30	6.17	2.39	1.50
d33	1.50	0.14	6.21
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	41.26
2	19	−26.27
3	26	−60.84
4	29	57.40
5	31	203.83
6	34	119.33

Numerical Example 2

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1*	10000.000	2.58	1.80400	46.5	0.5577
2	32.590	14.26
3	93.927	1.65	1.88300	40.8	0.5667
4	44.959	18.42
5	−43.953	1.65	1.77250	49.6	0.5520
6	−71.542	5.77
7	565.785	7.99	1.89286	20.4	0.6393
8	−117.933	1.61
9	115.176	9.95	1.49700	81.5	0.5375
10*	−159.676	11.65
11	−2566.642	9.34	1.43875	94.7	0.5340
12	−64.155	2.00	2.00100	29.1	0.5997
13	−74.025	0.20
14	104.797	1.84	1.96300	24.1	0.6212
15	47.782	11.71	1.49700	81.5	0.5375
16	−121.878	0.50
17	148.537	8.00	1.49700	81.5	0.5375
18	−140.367	(Variable)
19*	107.996	1.20	2.05090	26.9	0.6054
20	28.944	5.00
21	−82.229	0.83	1.49700	81.5	0.5375
22	28.282	4.39	1.85478	24.8	0.6122
23	−296.990	0.83	1.76385	48.5	0.5589
24	103.912	(Variable)
25	−46.645	0.83	1.88300	40.8	0.5667
26	73.071	2.06	1.92286	18.9	0.6495
27	−2265.947	(Variable)
28 (SP)	∞	1.00
29*	36.924	3.81	1.69680	55.5	0.5434
30	274.187	(Variable)
31	92.171	1.11	2.00069	25.5	0.6136
32	35.401	5.63	1.51823	58.9	0.5457
33	−87.881	35.00
34	87.968	4.90	1.49700	81.5	0.5375
35	−46.509	0.37
36	416.555	3.77	1.92286	18.9	0.6495
37	−49.455	0.83	1.91650	31.6	0.5911
38	262.820	10.00
39	51.195	6.72	1.43875	94.7	0.5340
40	−26.203	0.92	2.00100	29.1	0.5997
41	82.576	0.65
42	38.677	6.56	1.48749	70.2	0.5300
43	−70.233	38.98
Image Plane	∞
ASPHERIC DATA
1st Surface
K = 0.00000e+00	A4 = 4.18291e−06	A6 = −2.97629e−09	A8 = 2.26460e−12
A10 = −1.23261e−15	A12 = 3.82334e−19	A14 = −3.82317e−23	A16 = −4.93139e−27
10th Surface
K = 0.00000e+00	A4 = 1.39531e−06	A6 = −2.83059e−10	A8 = 1.22795e−13
A10 = −1.02418e−16	A12 = 3.09917e−20
19th Surface
K = 0.00000e+00	A4 = −7.21477e−07	A6 = −2.32086e−09	A8 = 1.93226e−11
A10 = −1.16522e−13	A12 = 2.44693e−16
29th Surface
K = 0.00000e+00	A4 = −5.27893e−06	A6 = 9.60956e−10	A8 = −3.16459e−12
VARIOUS DATA
ZOOM RATIO 4.00
	WIDE	MIDDLE	TELE
Focal Length	12.50	27.91	49.99
Fno	2.69	2.69	3.09
Half Angle of View(°)	49.82	27.94	16.49
Image Height	14.80	14.80	14.80
Overall Lens Length	291.28	291.28	291.28
BF	38.98	38.98	38.98
d18	0.50	26.13	37.11
d24	16.64	3.63	6.85
d27	19.96	13.83	1.29
d30	9.66	3.18	1.51
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	27.64
2	19	−36.85
3	25	−55.68
4	28	60.84
5	31	70.49

Numerical Example 3

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1	−298.726	1.60	1.89190	37.1	0.5780
2	147.923	2.01
3	158.765	4.92	1.98612	16.5	0.6657
4	287.958	2.39
5	280.011	11.22	1.49700	81.5	0.5375
6*	−185.843	9.43
7	179.212	2.10	1.85478	24.8	0.6122
8	87.572	0.27
9	89.176	11.76	1.53775	74.7	0.5392
10	−747.731	7.19
11	106.075	8.53	1.53775	74.7	0.5392
12	2546.824	1.00
13	92.547	8.34	1.61800	63.3	0.5426
14	866.235	(Variable)
15*	412.405	1.20	2.05090	26.9	0.6054
16	24.508	7.25
17	−38.635	0.80	1.52841	76.5	0.5396
18	30.110	6.51	1.85478	24.8	0.6122
19	−42.813	2.20
20	−27.265	0.75	1.76385	48.5	0.5589
21	−239.767	(Variable)
22	−55.914	0.90	1.88300	40.8	0.5667
23	94.395	3.48	1.85478	24.8	0.6122
24	−149.521	(Variable)
25*	74.801	6.89	1.76385	48.5	0.5589
26	−98.208	(Variable)
27	107.857	1.20	1.85478	24.8	0.6122
28	37.690	7.11	1.59522	67.7	0.5442
29	−361.701	(Variable)
30 (SP)	∞	1.00
31	275.057	4.41	1.53775	74.7	0.5392
32	−132.095	7.31
33	−77.008	2.00	1.88300	40.8	0.5667
34	−216.738	43.69
35	76.510	6.85	1.55200	70.7	0.5421
36	−62.564	6.44
37	48.673	7.98	1.89286	20.4	0.6393
38	−37.719	1.00	2.05090	26.9	0.6054
39	37.396	2.76
40	97.544	7.35	1.48749	70.2	0.5300
41	−25.465	0.90	1.89190	37.1	0.5780
42	174.494	0.51
43	38.737	8.55	1.48749	70.2	0.5300
44	−35.456	0.95	2.00069	25.5	0.6136
45	−55.422	37.99
Image Plane	∞
ASPHERIC DATA
6th Surface
K = −5.68862e−01	A4 = 5.47754e−08	A6 = −1.24236e−12	A8 = −1.07816e−15
15th Surface
K = 1.92279e+00	A4 = 3.81337e−06	A6 = −2.75045e−09	A8 = 1.48101e−11
A10 = −4.33253e−14	A12 = 8.22883e−17
25th Surface
K = 2.00015e+00	A4 = −2.15756e−06	A6 = 1.15981e−10	A8 = −1.57896e−13
VARIOUS DATA
ZOOM RATIO 11.51
	WIDE	MIDDLE	TELE
Focal Length	24.92	89.42	286.96
Fno	2.73	2.73	4.18
Half Angle of View(°)	30.70	9.40	2.95
Image Height	14.80	14.80	14.80
Overall Lens Length	318.17	318.17	318.17
BF	37.99	37.99	37.99
d14	1.00	38.59	54.70
d21	53.98	2.00	2.01
d24	7.03	21.18	1.16
d26	5.73	5.27	1.50
d29	1.72	2.42	10.09
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	83.13
2	15	−19.43
3	22	−98.42
4	25	56.56
5	27	369.96
6	30	133.92

Numerical Example 4

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1*	1000.000	2.60	1.78800	47.4	0.5559
2	32.299	23.71
3	−90.802	1.90	1.76385	48.5	0.5589
4	90.802	7.17
5	120.800	8.39	1.84666	23.8	0.6205
6	−305.584	1.50
7*	133.699	12.35	1.59522	67.7	0.5442
8	−82.940	10.44
9	1725.489	2.10	1.80518	25.4	0.6161
10	55.871	9.41	1.43875	94.7	0.5340
11	203.972	0.20
12	118.020	15.03	1.72916	54.7	0.5444
13	−67.209	(Variable)
14*	205.547	1.25	2.05090	26.9	0.6054
15	48.364	4.59
16	−203.099	1.25	1.59522	67.7	0.5442
17	56.505	5.21	1.95906	17.5	0.6598
18	387.830	5.28
19	−43.707	1.25	1.88300	40.8	0.5667
20	−72.099	(Variable)
21	−103.496	1.40	1.43875	94.7	0.5340
22	1152.733	(Variable)
23 (SP)	∞	1.00
24	74.231	6.01	1.80610	40.9	0.5713
25*	−252.102	(Variable)
26	34.472	5.90	1.51633	64.1	0.5353
27	72.860	3.50
28	59.699	1.30	2.00100	29.1	0.5997
29	29.646	11.36	1.43875	94.7	0.5340
30	−70.883	0.45
31	134.895	9.65	1.80810	22.8	0.6307
32	−31.578	1.30	2.00100	29.1	0.5997
33	−190.743	0.91
34	84.793	1.20	2.00100	29.1	0.5997
35	23.466	7.31	1.49700	81.5	0.5375
36	71.932	2.10
37	35.085	5.57	1.49700	81.5	0.5375
38	92.149	51.99
Surface Data	∞
ASPHERIC DATA
1st Surface
K = 0.00000e+00	A4 = 3.58870e−06	A6 = −2.14135e−09	A8 = 1.47525e−12
A10 = −8.12339e−16	A12 = 3.46755e−19	A14 = −1.00783e−22	A16 = 1.44431e−26
7th Surface
K = 0.00000e+00	A4 = −2.10391e−06	A6 = 7.90945e−10	A8 = −1.74703e−12
A10 = 3.45388e−15	A12 = −4.08574e−18	A14 = 2.61795e−21	A16 = −6.95832e−25
14th Surface
K = −7.36061e−01	A4 = 7.22343e−08	A6 = −1.52191e−10	A8 = 1.09496e−12
A10 = −2.08267e−15	A12 = 1.14680e−18
25th Surface
K = 0.00000e+00	A4 = 1.47861e−06	A6 = 2.63873e−10	A8 = −3.53362e−13
VARIOUS DATA
ZOOM RATIO 2.50
	WIDE	MIDDLE	TELE
Focal Length	20.00	35.00	49.99
Fno	2.30	2.30	2.30
Half Angle of View(°)	49.24	33.54	24.89
Image Height	23.20	23.20	23.20
Overall Lens Length	286.93	286.93	286.93
BF	51.99	51.99	51.99
d13	1.40	36.36	53.55
d20	30.44	3.04	1.55
d22	3.26	10.42	3.26
d25	27.26	12.55	3.99
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	51.49
2	14	−40.47
3	21	−216.38
4	23	71.73
5	26	91.86

Numerical Example 5

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1*	208.829	2.50	1.83481	42.7	0.5648
2	42.979	20.22
3*	−146.676	2.00	1.89190	37.1	0.5780
4	133.898	0.15
5	89.888	5.94	1.95906	17.5	0.6598
6	396.326	3.12
7	285.020	9.53	1.59522	67.7	0.5442
8*	−90.951	8.44
9	−124.552	5.54	1.43387	95.1	0.5373
10	−63.104	0.30
11	−62.877	1.70	1.80000	29.8	0.6017
12	−152.423	0.18
13	114.339	1.70	2.00100	29.1	0.5997
14	61.814	15.48	1.49700	81.5	0.5375
15	−121.372	0.20
16	356.300	10.87	1.43387	95.1	0.5373
17	−76.581	0.20
18	80.452	8.31	1.76385	48.5	0.5589
19	−12653.070	(Variable)
20*	72.226	0.70	2.05090	26.9	0.6054
21	16.800	4.06
22	−155.568	0.70	1.43875	94.7	0.5340
23	42.302	2.72
24	−146.175	5.36	1.85478	24.8	0.6122
25	−15.612	0.70	1.88300	40.8	0.5667
26	74.487	0.43
27	36.672	2.88	1.73800	32.3	0.5900
28	−220.003	(Variable)
29	−30.840	0.80	1.72916	54.7	0.5444
30	49.687	2.38	1.84666	23.8	0.6205
31	1984.632	(Variable)
32 (SP)	∞	1.00
33*	118.953	5.04	1.89190	37.1	0.5780
34	−75.584	(Variable)
35	46.778	5.33	1.51742	52.4	0.5564
36	−98.699	1.00	1.83481	42.7	0.5648
37	105.890	(Variable)
38	56.779	1.00	1.95375	32.3	0.5905
39	24.833	5.63	1.51633	64.1	0.5353
40	−431.483	35.00
41	97.774	6.00	1.63980	34.5	0.5922
42	−44.117	0.80
43	−140.597	0.90	1.88300	40.8	0.5667
44	27.791	5.14	1.55200	70.7	0.5421
45	−178.218	0.50
46	43.965	6.20	1.43875	94.7	0.5340
47	−33.355	0.90	2.00100	29.1	0.5997
48	−64.288	0.50
49	301.737	2.31	1.48749	70.2	0.5300
50	−95.058	4.00
51	∞	33.00	1.60859	46.4	0.5664
52	∞	13.20	1.51680	64.2	0.5347
53	∞	7.45
Image Plane	∞
ASPHERIC DATA
1st Surface
K = 0.00000e+00	A4 = −7.47662e−06	A6 = −1.47215e−07	A8 = −2.46563e−10
A10 = 4.11514e−13	A12 = 1.22984e−16	A14 = −1.08151e−19	A16 = −5.20408e−24
A3 = 2.09871e−05	A5 = 1.42449e−06	A7 = 8.72980e−09	A9 = −2.02602e−12
A11 = −1.32062e−14	A13 = 3.20728e−18	A15 = 1.23717e−21
3rd Surface
K = 0.00000e+00	A4 = 1.01909e−05	A6 = 2.91856e−07	A8 = 2.33150e−09
A10 = 6.11514e−12	A12 = 2.38406e−15	A14 = −1.91675e−18	A16 = −2.08863e−22
A3 = −2.52129e−05	A5 = −2.14476e−06	A7 = −2.95677e−08	A9 = −1.40308e−10
A11 = −1.75105e−13	A13 = 2.93400e−17	A15 = 3.29607e−20
8th Surface
K = 0.00000e+00	A4 = 3.94298e−06	A6 = −7.42330e−08	A8 = −1.93707e−09
A10 = −5.79331e−12	A12 = −3.06732e−15	A14 = −6.44985e−19	A16 = −8.11343e−23
A3 = −1.14993e−05	A5 = −1.55382e−07	A7 = 1.74480e−08	A9 = 1.31655e−10
A11 = 1.65574e−13	A13 = 4.17505e−17	A15 = 1.03987e−20
20th Surface
K = 1.55546e+00	A4 = 2.78255e−07	A6 = −4.73484e−10	A8 = −4.37626e−12
33rd Surface
K = −3.93401e+01	A4 = 1.76086e−06	A6 = −2.89485e−09	A8 = 2.28335e−12
VARIOUS DATA
ZOOM RATIO 18.02
	WIDE	MIDDLE	TELE
Focal Length	5.50	21.02	99.12
Fno	1.86	1.86	2.97
Half Angle of View(°)	45.00	14.67	3.18
Image Height	5.50	5.50	5.50
Overall Lens Length	324.65	324.65	324.65
BF	7.45	7.45	7.45
d19	0.65	36.44	52.33
d28	35.32	3.10	16.62
d31	18.13	21.19	1.24
d34	17.56	1.00	1.00
d37	1.00	10.92	1.45
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	40.24
2	20	−18.35
3	29	−46.09
4	32	52.46
5	35	2340.64
6	38	49.70

Numerical Example 6

UNIT: mm
SURFACE DATA
Surface No.	r	d	nd	vd	θgF
1*	1658.310	2.50	1.83481	42.7	0.5648
2	31.052	17.12
3*	165.877	2.00	1.83481	42.7	0.5648
4	86.855	9.99
5	−94.683	1.80	1.83481	42.7	0.5648
6	−532.838	0.15
7	94.232	4.27	1.92286	18.9	0.6495
8	357.216	1.71
9	166.608	8.24	1.60300	65.4	0.5401
10*	−97.414	4.41
11	−603.969	7.95	1.43387	95.1	0.5373
12	−55.416	0.33
13	−53.264	1.70	1.80000	29.8	0.6017
14	−109.667	0.18
15	168.829	1.70	1.91650	31.6	0.5911
16	53.722	13.56	1.43875	94.7	0.5340
17	−120.939	0.40
18	978.223	9.10	1.43387	95.1	0.5373
19	−66.338	0.40
20	111.808	8.12	1.76385	48.5	0.5589
21	−168.562	(Variable)
22*	135.706	0.70	2.05090	26.9	0.6054
23	17.909	3.93
24	−62.560	0.70	1.43875	94.7	0.5340
25	81.625	2.11
26	−164.446	5.71	1.85478	24.8	0.6122
27	−14.283	0.70	1.88300	40.8	0.5667
28	157.961	0.21
29	41.883	2.86	1.73800	32.3	0.5900
30	−191.791	(Variable)
31	−32.514	0.80	1.72916	54.7	0.5444
32	45.779	2.59	1.84666	23.8	0.6205
33	2489.967	(Variable)
34*	65.079	6.37	1.58913	61.1	0.5407
35	−53.660	(Variable)
36 (SP)	∞	1.95
37	130.028	5.31	1.51742	52.4	0.5564
38	−45.807	1.00	1.83481	42.7	0.5648
39	−171.417	35.50
40	62.385	5.48	1.63980	34.5	0.5922
41	−50.700	1.53
42	−91.839	0.90	1.88300	40.8	0.5667
43	27.881	5.28	1.48749	70.2	0.5300
44	−140.321	0.20
45	61.712	7.86	1.43875	94.7	0.5340
46	−20.931	0.90	2.00100	29.1	0.5997
47	−54.391	0.13
48	143.444	5.38	1.48749	70.2	0.5300
49	−31.599	4.00
50	∞	33.00	1.60859	46.4	0.5664
51	∞	13.20	1.51680	64.2	0.5347
52	∞	7.45
Image Plane	∞
ASPHERIC DATA
1st Surface
K = 0.00000e+00	A4 = 4.07369e−06	A6 = 1.07123e−08	A8 = 7.80444e−12
A10 = 9.49529e−14	A12 = 1.11177e−16	A14 = 1.85178e−20	A16 = −6.42205e−26
A3 = 1.27705e−05	A5 = −1.68113e−07	A7 = −3.07821e−10	A9 = −1.17404e−12
A11 = −4.11434e−15	A13 = −1.90018e−18	A15 = −7.33161e−23
3rd Surface
K = 0.00000e+00	A4 = −2.28149e−06	A6 = −7.50517e−08	A8 = −7.10699e−10
A10 = −3.23653e−13	A12 = 1.59720e−15	A14 = −6.51703e−19	A16 = −2.02837e−22
A3 = −1.08050e−05	A5 = 4.35381e−07	A7 = 9.13498e−09	A9 = 3.03383e−11
A11 = −3.27445e−14	A13 = −1.78369e−17	A15 = 2.23156e−20
10th Surface
K = 0.00000e+00	A4 = 1.14792e−06	A6 = 1.37632e−08	A8 = 2.71470e−10
A10 = 2.08439e−13	A12 = −7.68942e−16	A14 = 1.05267e−18	A16 = 2.18868e−22
A3 = −3.26263e−06	A5 = −2.00722e−08	A7 = −2.66909e−09	A9 = −1.44185e−11
A11 = 1.68145e−14	A13 = −4.82496e−18	A15 = −2.63977e−20
22nd Surface
K = 3.26077e+01	A4 = 3.46197e−06	A6 = 4.66573e−08	A8 = −2.68025e−10
A10 = 2.62133e−12
A3 = −2.92893e−06	A5 = −7.62030e−07	A7 = 3.83578e−09	A9 = −3.83807e−11
34th Surface
K = −1.23593e+01	A4 = 1.51830e−06	A6 = −4.16722e−09	A8 = 2.26731e−12
VARIOUS DATA
ZOOM RATIO 13.61
	WIDE	MIDDLE	TELE
Focal Length	4.43	15.50	60.26
Fno	1.86	1.86	2.77
Half Angle of View(°)	51.16	19.54	5.22
Image Height	5.50	5.50	5.50
Overall Lens Length	315.65	315.65	315.65
BF	7.45	7.45	7.45
d21	0.65	35.73	52.42
d30	41.36	5.66	4.62
d33	14.46	17.85	2.09
d35	7.81	5.04	5.15
LENS UNIT DATA
Lens Unit	Starting Surface	Focal Length
1	1	29.67
2	22	−20.17
3	31	−49.54
4	34	50.93
5	36	52.86

	Numerical Example
	Inequality	1	2	3	4	5	6
(1)	nn	2.05	2.05	2.05	2.05	2.05	2.05
(2)	vn	26.9	26.9	26.9	26.9	26.9	26.9
(3)	fl/fw	2.7	2.2	3.3	2.6	7.3	6.7
(4)	fn/fV	1.1	1.0	1.3	1.5	1.1	1.0
(5)	θn + 0.00162 × vn	0.65	0.65	0.65	0.65	0.65	0.65
(6)	v	82	82	76	68	95	95
(7)	(θpave − θnave)/	−0.0017	−0.0016	−0.0017	−0.0032	−0.0013	−0.0013
	(vpave − vnave)
(8)	fV/fw	−1.7	−2.9	−0.8	−2.0	−3.3	−4.6
(9)	fw/IS	0.5	0.4	0.8	0.5	0.5	0.4
	fl	41.3	27.6	83.0	51.5	40.2	29.7
	fw	15.1	12.5	24.9	20.0	5.5	4.4
	fn	−27.9	−37.9	−24.6	−60.4	−21.0	−19.7
	fV	−26.3	−36.9	−19.4	−40.5	−18.3	−20.2
	θpave	0.612	0.612	0.612	0.660	0.601	0.601
	θnave	0.570	0.567	0.568	0.572	0.569	0.569
	vpave	24.80	24.80	24.80	17.47	28.57	28.57
	vnave	49.75	52.32	50.63	45.15	54.12	54.12
	IS	29.6	29.6	29.6	43.3	11.0	11.0

Image Pickup Apparatus

FIG. 13 illustrates an image pickup apparatus using the zoom lens according to any one of the above examples as an imaging optical system. In FIG. 13, reference numeral 101 denotes one of the zoom lenses according to Examples 1 to 6. Reference numeral 124 denotes a camera body. An image pickup apparatus 125 is configured by detachably attaching the zoom lens 101 to the camera body 124. However, the image pickup apparatus may be one in which the zoom lens 101 is integrated with the camera body 124.

The zoom lens 101 includes a first lens unit F, a zoom unit LZ, and an imaging lens unit R. The first lens unit F includes a focus subgroup that moves during focusing.

The zoom unit LZ includes at least three or more lens units that move during zooming. An aperture stop SP, a lens unit R1, and a lens unit R2 are disposed on the image side of the zoom unit LZ. The image pickup apparatus 125 also includes a lens unit IE that can be inserted into and removed from the optical path between the lens unit R1 and the lens unit R2. By inserting the lens unit IE, a focal length range of the zoom lens 101 can be changed.

Reference numerals 114 and 115 denote drive mechanisms that drive the first lens unit F and the zoom unit LZ in the optical axis direction, respectively. Reference numerals 116 to 118 denote drive units including actuators that drive the drive mechanisms 114 and 115 and the aperture stop SP. Reference numerals 119 to 121 denote detectors for detecting the position of the focus subgroup on the optical axis, the position of the zoom unit LZ on the optical axis, and the aperture diameter of the aperture stop SP. In the camera body 124, reference numeral 109 denotes a glass block including an optical filter, etc., and reference numeral 110 denotes an image sensor such as a CCD sensor or CMOS sensor configured to photoelectrically convert (captures) an object image formed by the zoom lens 101. Reference numerals 111 and 122 denote CPUs that serve as processing units (control units) in the camera body 124 and the zoom lens 101, respectively.

Using the zoom lens according to any one of the above example as an imaging optical system can provide an image with good image quality across the entire zoom range with a wide angle of view and a high zoom ratio.

While the disclosure has described example embodiments, it is to be understood that some embodiments are not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Each example can provide a zoom lens having a wide angle of view, a high zoom ratio, and high optical performance over the entire zoom range.

This application claims priority to Japanese Patent Application No. 2023-207367, which was filed on Dec. 8, 2023, and which is hereby incorporated by reference herein in its entirety.

Claims

1. A zoom lens comprising, in order from an object side to an image side: a first lens unit having positive refractive power that does not move during zooming;an intermediate group including at least three lens units that move during zooming; anda final lens unit having positive refractive power that does not move during zooming,wherein a distance between adjacent lens units changes during zooming,wherein the intermediate group includes at least one lens unit having negative refractive power,wherein a lens unit having negative refractive power and closest to an object among the at least one lens unit having negative refractive power includes at least one negative lens, andwherein the following inequalities are satisfied:

2. The zoom lens according to claim 1, wherein the following inequality is satisfied:

3. The zoom lens according to claim 1, wherein the following inequality is satisfied:

4. The zoom lens according to claim 1, wherein the negative lens closest to the object is an aspheric lens.

5. The zoom lens according to claim 1, wherein the lens unit having negative refractive power and closest to the object includes at least four lenses.

6. The zoom lens according to claim 1, wherein the following inequality is satisfied: 60≤v≤100where v is an Abbe number based on the d-line of the at least one negative lens.

7. The zoom lens according to claim 1, wherein the following inequality is satisfied:

8. The zoom lens according to claim 1, wherein the following inequality is satisfied:

9. The zoom lens according to claim 1, wherein a part of the first lens unit moves for focusing.

10. An image pickup apparatus comprising: a zoom lens; andan image sensor configured to capture an object image through the zoom lens,wherein the zoom lens includes, in order from an object side to an image side:a first lens unit having positive refractive power that does not move during zooming;an intermediate group including at least three lens units that move during zooming; anda final lens unit having positive refractive power that does not move during zooming,wherein a distance between adjacent lens units changes during zooming,wherein the intermediate group includes at least one lens unit having negative refractive power,wherein a lens unit having negative refractive power and closest to an object among the at least one lens unit having negative refractive power includes at least one negative lens, andwherein the following inequalities are satisfied:

11. The image pickup apparatus according to claim 10, wherein the following inequality is satisfied: