JP2014063026A - Zoom lens and imaging apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens capable of easily obtaining high optical performance over the whole zoom range and over the whole object distance.SOLUTION: The zoom lens includes: a first lens group having a positive refractive power; a second lens group having a negative refractive power; an aperture stop; and a rear group including a plurality of lens groups, and when zooming, the second lens group and at least two lens groups in the rear group are moved. The first lens group includes a first-a lens group having a negative refractive power and a first-b lens group having a positive refractive power. The first-a lens group includes a first-a1 lens group having a negative refractive power and a first-a2 lens group having a positive refractive power and being moved when focusing. The amount m1 of movement of a lens group in the rear group whose amount of movement during zooming is largest, the amount mi of movement of another lens group in the rear group, the focal distances f1, f2 of the first lens group and the second lens group, the principal point intervals h12w, h12t between the first lens group and the second lens group at the wide angle end and at the telephoto end, the distances sw, st between the lens surface closest to the image side in the second lens group and the aperture stop at the wide angle end and at the telephoto end, and the zoom ratio Z are appropriately set, respectively.

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same. For example, an image pickup apparatus using a solid-state image pickup device such as a video camera, an electronic still camera, a broadcast camera, a surveillance camera, or a camera using a silver salt film. It is suitable for an imaging device. In addition, it is suitable for a projection device that projects an image.

  In recent years, imaging devices such as a video camera and a broadcast television camera that can shoot moving images in high-definition broadcasting and HD standards have become widespread, and the output video from the imaging device has been improved in image quality. Zoom lenses used in these image pickup devices are required to have high optical performance (resolution) corresponding to the increase in the number of pixels from the image pickup device and the increase in pixel density. Further, there is a demand that the zoom magnification does not change due to focusing.

  Conventionally, as a zoom lens used in a television camera for broadcasting, a positive lead type zoom lens in which a lens group having a positive refractive power is disposed closest to the object side is known (Patent Document 1). In Patent Document 1, the first to fifth lens groups having positive, negative, positive, negative, and positive refractive powers are arranged in order from the object side to the image side, and an aperture stop is provided between the second lens group and the third lens group. Is arranged. Then, zooming is performed by moving the second lens group on the object side from the aperture stop and the fourth lens group on the image side from the aperture stop.

  On the other hand, when three or more lens groups are moved during zooming, it becomes easy to correct aberration fluctuations accompanying zooming. In a zoom lens used in an imaging apparatus such as a digital camera, a zoom lens is known in which three or more lens groups are moved during zooming to reduce aberration fluctuations associated with zooming (Patent Document 2). In Patent Document 2, the first to fourth lens groups having positive, negative, positive, and positive refractive power are sequentially arranged from the object side to the image side, and zooming is performed by moving the first lens group to the fourth lens group. ing.

JP 2000-105336 A JP 2009-80483 A

  In recent years, a zoom lens used in an imaging apparatus such as a TV camera is required to obtain a high image quality equivalent to Super Hi-Vision over the entire zoom range. In addition, zoom lenses used in video cameras, digital still cameras, and the like are also required to have high optical performance over the entire zoom range.

  In order to obtain high optical performance over the entire zoom range and the entire object distance, it is important that various aberrations are corrected well over the entire zoom range and the entire object distance, in particular, the field curvature is corrected well. It becomes. In the above-described positive lead type zoom lens, it is important to appropriately configure the zoom type, the lens group to be moved during zooming or focusing, and the movement conditions thereof. If the configuration at this time is inappropriate, it becomes difficult to obtain a zoom lens having high optical performance over the entire zoom range and the entire object distance.

  In a zoom lens in which only two lens groups move during zooming, aberration fluctuations caused by zooming, particularly fluctuations in field curvature, are large, and it is difficult to obtain high optical performance over the entire zoom range. Further, the first lens group (front lens) in the zoom lens for a TV camera has a large effective diameter and is heavy. For this reason, it is difficult to perform focusing at high speed in the method of performing focusing on the entire first lens unit.

  In addition, when zooming from the wide-angle end to the telephoto end, if the entrance pupil diameter does not increase corresponding to zooming, the F-number fluctuates during zooming, and when the F-number increases at the telephoto end, the entrance pupil diameter becomes relatively small. The influence of image quality deterioration due to diffraction cannot be ignored. For this reason, in order to obtain high optical performance over the entire zoom range, it is important to set the entrance pupil diameter so as to correspond to zooming and to reduce the deterioration in image quality due to diffraction.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens and an image pickup apparatus having the same that can easily obtain high optical performance over the entire zoom range and the entire object distance.

The zoom lens of the present invention has a rear group including a first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, and a plurality of lens groups in order from the object side to the image side. During zooming, in the zoom lens in which the first lens group is stationary and at least two lens groups of the second lens group and the rear group are moved, the first lens group is sequentially moved from the object side to the image side. The first a lens group having a negative refractive power and the first b lens group having a positive refractive power are arranged in order from the object side to the image side. It is composed of a first a2 lens unit having a positive refractive power that moves, and m1 represents the amount of movement of the lens unit having the maximum amount of movement in zooming from the wide-angle end to the telephoto end in the rear group, and the other lens units of the rear group The movement amount of the first lens The focal lengths of the first lens group and the second lens group are f1 and f2, respectively, and the principal point intervals of the first lens group and the second lens group at the wide-angle end and the telephoto end are h12w and h12t, respectively. The distance from the lens surface closest to the image side of the two lens groups to the aperture stop is Sw and St, and the zoom ratio is Z.
Zp = {(Sw + f2) (f1 + f2-h12w)-(f2 ² )} / {(St + f2) (f1 + f2-h12t)-(f2 ² )}
When you leave
1.1 <m1 / mi <15
1.1 <Z / Zp <2.0
It satisfies the following conditional expression.

  According to the present invention, it is possible to obtain a zoom lens that can easily obtain high optical performance over the entire zoom range and the entire object distance.

Sectional view of the lens at the wide-angle end of Embodiment 1 (A), (B) Aberration diagrams at the wide-angle end and the telephoto end of Example 1 of the present invention. Sectional view of the lens at the wide-angle end of Embodiment 2 of the present invention (A), (B) Aberration diagrams at the wide-angle end and the telephoto end of Example 2 of the present invention. Sectional view of the lens at the wide-angle end of Embodiment 3 (A), (B) Aberration diagrams at the wide-angle end and the telephoto end of Example 3 of the present invention. Cross-sectional view of a lens at a wide angle end according to Embodiment 4 of the present invention (A), (B) Aberration diagrams at the wide-angle end and the telephoto end of Example 4 of the present invention Schematic diagram of main parts of an imaging apparatus of the present invention

  Embodiments of a zoom lens and an image pickup apparatus having the same according to the present invention will be described below with reference to the accompanying drawings. The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, and a rear group including a plurality of lens groups. Yes. During zooming, the first lens group does not move, and at least two lens groups, the second lens group and the rear group, move. The first lens group includes, in order from the object side to the image side, a first a1 lens group having a negative refractive power, a first a2 lens group having a positive refractive power for focusing, and a first b lens group having a positive refractive power. A synthetic first-a lens group composed of a lens group and a first-a2 lens group has a negative refractive power.

  FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 1 of the present invention. FIGS. 2A and 2B are aberration diagrams at the wide-angle end and the telephoto end (long focal length end), respectively, of the zoom lens according to the first exemplary embodiment. FIG. 3 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 2 of the present invention. 4A and 4B are aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end, respectively. FIG. 5 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention. 6A and 6B are aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end, respectively.

  FIG. 7 is a lens cross-sectional view at the wide-angle end of the zoom lens according to a fourth exemplary embodiment of the present invention. 8A and 8B are aberration diagrams of the zoom lens of Example 4 at the wide-angle end and the telephoto end, respectively. Lens cross-sectional views and aberration diagrams show when the object distance is infinite. FIG. 9 is a schematic diagram of a main part when applied to a TV camera (imaging device) as an example including the zoom lens of the present invention. The zoom lens of each embodiment is a photographing lens system used in an imaging device such as a TV camera. is there. In the lens cross-sectional view, the left side is the subject side (object side) (front), and the right side is the image side (rear). In each lens cross-sectional view, L0 is a zoom lens.

  i represents the order of the lens groups from the object side to the image side, and Li represents the i-th lens group. LR is a rear group including a plurality of lens groups. SP is an aperture (aperture stop) that determines the axial maximum beam diameter at the wide-angle end. Here, the “aperture that determines the maximum axial beam diameter” means that the F number is determined for the axial beam when the object distance is infinity (the light beam in which the principal ray travels on the optical axis). It refers to the opening.

  1 and 3, L1 is a first lens group having a positive refractive power (optical power = reciprocal of focal length), L2 is a second lens group having a negative refractive power, and FIGS. L3 is a third lens group having a positive refractive power, and L4 is a fourth lens group having a positive refractive power. L5 is a fifth lens unit having a positive refractive power. The rear group LR includes a third lens unit L3 having a positive refractive power, a fourth lens unit L4 having a positive refractive power, and a fifth lens unit L5 having a positive refractive power.

  The first lens unit L1 includes, in order from the object side to the image side, a first-a lens unit L1a having a negative refractive power and a first-b lens unit L1b having a positive refractive power. The first a lens unit L1a includes, in order from the object side to the image side, a first a1 lens unit L1a1 having a negative refractive power and a first a2 lens unit L1a2 having a positive refractive power that moves during focusing. The first-a lens unit L1a has a negative refractive power in the entire focusing region. The aperture stop SP is located between the second lens unit L2 and the third lens unit L3. GB is an optical block corresponding to a color separation prism, an optical filter, or the like.

  IP is an image plane on which an imaging surface of an imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is placed. During zooming, the first lens unit L1 does not move. During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image side as indicated by an arrow. The third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5 move independently of each other (with different tracks) while drawing a convex track on the object side. The aperture stop SP moves independently of the other lens groups.

  5 and 7, L1 is a first lens unit having a positive refractive power, L2 is a second lens unit having a negative refractive power, L3 is a third lens unit having a negative refractive power, and L4 is a third lens unit having a negative refractive power. A fourth lens group having a positive refractive power, L5 is a fifth lens group having a positive refractive power, and L6 is a sixth lens group having a positive refractive power. The rear group LR includes a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a positive refractive power.

  In order from the object side to the image side, the first lens unit L1 includes a first a1 lens unit L1a1 having a negative refractive power, a first a2 lens unit L1a2 having a positive refractive power for focusing, and a first b lens unit L1b having a positive refractive power. It is configured. The combined first a lens unit L1a including the first a1 lens unit L1a1 and the first a2 lens unit L1a2 has a negative refractive power in the entire focusing region.

  The aperture stop SP is disposed between the second lens unit L2 and the third lens unit L3. GB is an optical block, and IP is an image plane. During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image side. The third lens unit L3 moves along a locus convex toward the object side. The fourth lens unit L4 and the fifth lens unit L5 move independently of each other toward the object side. The first lens unit L1 and the sixth lens unit L6 do not move for zooming. In Example 3 of FIG. 5, the aperture stop SP moves independently of the other lens groups. In Example 4 of FIG. 7, the aperture stop SP moves integrally with the third lens unit L3 (same locus).

  In the aberration diagrams, d-line is d-line and g-line is g-line. ΔM and ΔS are a meridional image plane and a sagittal image plane at d-line. Lateral chromatic aberration is represented by the g-line. Fno is the F number, and ω is the half angle of view. In the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zoom lens group is positioned at both ends of a range in which the zoom lens group can move on the optical axis.

  In a zoom lens for a TV camera, it is known that a rear group has a function of correcting image plane fluctuations accompanying zooming, a so-called competition function. In the present invention, the rear group has a function other than the competition function, for example, an aberration correction function. That is, the rear group is constituted by a plurality of lens groups that are driven while having a relative driving amount relationship.

  In addition, when the aperture stop and the rear group are driven to increase the zoom ratio of the zoom lens, the zoom ratio becomes larger than the magnification of the entrance pupil diameter. As a result, the F number increases on the telephoto side, and the image quality due to diffraction deteriorates. Deterioration of image quality due to this diffraction is a major issue.

  Therefore, in the present invention, the aberration variation during zooming is suppressed by driving the two or more lens groups in the rear group while maintaining a certain relationship, and at the same time, the aperture stop and the rear group are driven to reduce the entrance pupil diameter. Considering the change, the influence of the diffraction limit is reduced.

  In each embodiment, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and an aperture stop are sequentially arranged from the object side to the image side. Let Zp be the zoom ratio of the entrance pupil diameter due to zooming from the wide-angle end to the telephoto end. The zoom ratio Zp is obtained when the aperture stop is imaged by the lens group (first and second lens groups) on the object side. That is, it is approximated as follows by multiplying the corresponding lateral magnifications.

Zp = {(Sw + f2) (f1 + f2-h12w)-(f2 ² )} / {(St + f2) (f1 + f2-h12t)-(f2 ² )}
In the present invention, attention is paid to the relationship between the principal point interval h12w and the principal point interval h12t in order to increase the value of the zoom ratio Zp during zooming. The difference is large, that is, the zoom ratio of the object side lens unit (first and second lens units) is set high with respect to the aperture stop.

  Most of the zoom lenses used in TV cameras are, in order from the object side to the image side, a front lens group having a positive refractive power, a variable power lens group having a negative refractive power for zooming, and an image plane variation accompanying zooming. Correction lens group, and a relay lens group having a positive refractive power. Since this zoom lens is zoomed only by the lens group on the object side of the aperture stop, the relationship between the zoom ratio Zp and the zoom ratio is substantially the same, that is, 1. In this case, it is difficult to achieve a high image quality because it cannot be expected to share the variable magnification of the lens group on the image side from the aperture stop, and the aberration correction effect.

  Therefore, in the present invention, in order to reduce the effective diameter of the front lens at the wide angle end, the position of the aperture stop is arranged on the object side. Specifically, each member is driven so as to increase the difference between the distances Sw and St from the lens surface closest to the image side of the second lens unit L2 at the wide-angle end and the telephoto end to the aperture stop SP, and the zoom ratio Zp Has increased. In addition, regarding the measuring method for the magnification ratio Zp of the entrance pupil diameter in the embodiment, the zoom lens is illuminated from the image side by placing a pinhole at the focus position. At this time, the screen may be disposed close to the object side of the zoom lens and the diameter of the light beam projected thereon may be measured at the wide-angle end and the telephoto end.

  In addition, the variables related to the zoom ratio Zp corresponding thereto can be calculated from the measurement of numerical examples of the zoom lens (the radius of curvature of the lens, the thickness, the refractive index of the material, etc.).

In each embodiment, the movement amount of the lens group having the maximum movement amount during zooming from the wide-angle end to the telephoto end in the rear group LR is m1, and the movement amounts of the other lens groups are mi. The focal lengths of the first lens unit L1 and the second lens unit L2 are f1 and f2, respectively. The principal point intervals of the first lens unit L1 and the second lens unit L2 at the wide-angle end and the telephoto end are set to h12w and f12t, respectively. The distances from the most image-side lens surface of the second lens unit L2 at the wide-angle end and the telephoto end to the aperture stop SP are Sw and St, respectively, and the zoom ratio is Z.
Zp = {(Sw + f2) (f1 + f2-h12w)-(f2 ² )} / {(St + f2) (f1 + f2-h12t)-(f2 ² )}
far. At this time,
1.1 <m1 / mi <15 (1)
1.1 <Z / Zp <2.0 (2)
The following conditional expression is satisfied.

  Here, the sign of the movement amount is positive for the movement amount to the image side. In each embodiment, the first lens unit L1 having positive refractive power is disposed closest to the object side, and the second lens unit L2 having negative refractive power disposed adjacently is driven to change the magnification. Therefore, the zoom ratio is increased. Since the front lens (first lens unit L1) is feared to be large and heavy, the first lens unit L1 is fixed. Then, the first lens unit L1 is sequentially moved from the object side to the image side by a first a1 lens unit L1a1 having a negative refractive power, a first a2 lens unit L1a2 having a positive refractive power for focusing, and a first b lens unit L1b having a positive refractive power. It is composed.

  Accordingly, the main plane of the first lens unit L1 is disposed on the image side, the refractive power of the second lens unit L2 is relaxed, and aberration (curvature) fluctuation during zooming is reduced. The first a2 lens unit L1a2 is focused (focused), thereby suppressing the magnification fluctuation at the time of focusing on the object at close range. Further, at the time of zooming, at least two lens units in the rear group LR are moved to increase the resolution. At this time, conditional expressions (1) and (2) are satisfied.

  Conditional expression (1) defines the ratio of the moving amount of the other moving lens unit to the moving amount of the lens unit having the maximum moving amount during zooming in the rear group LR. If the lower limit of conditional expression (1) is exceeded, this is equivalent to the movement of the lens group having the largest movement amount and the other lens group, making it difficult to correct the curvature aberration. On the contrary, if the upper limit is exceeded, it becomes equivalent to the situation where other lens groups are fixed, so that it becomes difficult to correct the bending aberration due to the movement of the plurality of lens groups. Desirably, by setting the following conditional expression (1a) range, it becomes easy to achieve a zoom lens in which the variation of various aberrations is further reduced.

1.1 <m1 / mi <10 (1a)
In addition, it is preferable that all the lens groups that move by zooming in the rear group LR satisfy the conditional expression (1) or the conditional expression (1a).

  Conditional expression (2) defines an approximate equivalent value of the magnification ratio and the ratio of the entrance pupil diameter magnification at the time of magnification. If the lower limit of conditional expression (2) is exceeded, the variable magnification sharing by the rear lens group LR will be insufficient, aberration correction will be insufficient, and high zoom ratio will be difficult. Conversely, when the upper limit is exceeded, image quality deterioration due to diffraction increases near the telephoto end. Desirably, by setting the following conditional expression (2a) range, it becomes easy to achieve a zoom lens in which various aberration variations are further reduced and the influence of diffraction due to the F number becoming dark at the telephoto end is small.

1.1 <Z / Zp <1.7 (2a)
In each embodiment, the combined first a lens unit L1a including the first a1 lens unit L1a1 having a negative refractive power and the first a2 lens unit L1a2 having a positive refractive power has a negative refractive power. Then, focusing is performed by the first a2 lens unit L1a2.

  The first-a lens unit L1a having a negative refractive power has a lens configuration having a weak refractive power, so that the driving sensitivity at the time of focusing is small, and the first-a lens unit L1a is not suitable for focusing. For this reason, the first a lens group L1a is divided into a first a1 lens group L1a1 and a first a2 lens group L1a2, and the lighter first a2 lens group L1a2 is focused. As a result, the change in magnification is reduced even when an object at close range is in focus.

  As described above, according to the present invention, it is possible to obtain a high-quality and high-quality zoom lens that can obtain a sufficient aberration correction effect and suppress deterioration in image quality due to diffraction. In each embodiment, it is more preferable to satisfy one or more of the following conditional expressions. Let the focal length of the first a2 lens unit L1a2 be f1a2. The rear group LR includes a lens group LX1 that moves along a locus convex toward the object side during zooming from the wide-angle end to the telephoto end, and a lens group LX2 that moves adjacent to the lens group LX1. The maximum distance between the lens unit LX1 and the lens unit LX2 during zooming is Lmax, and the minimum interval is Lmin.

  When the distance from the aperture stop SP to the front main plane position of the rear group LR is 0r1, the focal length of the rear group LR is fr, and the ratio (0r1 / fr) of the distance 0r1 to the focal length fr is the maximum and minimum over the entire zoom range The difference between the values is Δ (0r1 / fr). At this time, it is preferable to satisfy one or more of the following conditional expressions.

1 <f1a2 / f1 <5 (3)
2 <Lmax / Lmin <10 (4)
0.9 <0r1 / fr <2.0 (5)
Δ (0r1 / fr) <1.0 (6)
Next, the technical meaning of each conditional expression described above will be described.

  Conditional expression (3) defines the focal length ratio between the first a2 lens unit L1a2 and the first lens unit L1. If the lower limit of conditional expression (3) is exceeded, if the refractive power of the first a2 lens unit L1a2 becomes too strong, fluctuations in aberrations during focusing increase. On the contrary, if the upper limit is exceeded, the amount of movement of the first a2 lens unit L1a2 during focusing increases, and aberration fluctuations increase. Desirably, by setting the following conditional expression (3a) range, it becomes easier to achieve a zoom lens with less aberration fluctuation at the time of focusing.

2 <f1a2 / f1 <4 (3a)
In each embodiment, the rear group LR includes a lens group LX1 that moves along a convex locus toward the object side during zooming from the wide-angle end to the telephoto end, and a lens group LX2 that moves adjacent thereto. In zooming, the maximum distance Lmax and the minimum distance Lmin between the lens unit LX1 and the lens unit LX2 satisfy the conditional expression (4).

  Conditional expression (4) is for reducing the fluctuation of the curvature of the image plane in the intermediate zoom range. Exceeding the lower limit of conditional expression (4) makes it difficult to correct field curvature in the intermediate zoom range. On the other hand, if the upper limit is exceeded, the correction of field curvature becomes excessive in the middle of the zoom. Desirably, by setting the range in the following conditional expression (4a), it becomes easy to achieve a zoom lens with less aberration fluctuation such as a curvature at the time of zooming.

3 <Lmax / Lmin <7 (4a)
In each embodiment, there are three lens groups having positive refractive power from the image side to the object side. In a TV camera, a color separation element or the like is inserted on the image side of a zoom lens, and an image with a higher image quality is obtained by using a plurality of image pickup elements for each color. In the case of such a configuration, it is desirable to consider a condition regarding the exit-side pupil in addition to the above-described entrance-side pupil diameter zoom ratio condition. That is, it is desirable that the zoom lens has a pupil position far from the image plane. For this reason, a lens group arranged on the image side is preferably configured with a positive refractive power.

  Conditional expressions (5) and (6) define the distance 0r1 from the aperture stop SP to the front main plane position of the rear group LR and the focal length fr of the rear group LR. Conditional expression (5) defines the ratio between the front main plane position of the rear group LR and the focal length. Regardless of whether the upper limit or the lower limit of conditional expression (5) is exceeded, the angle of light incident on the color separation surface of the color separation element varies greatly depending on the angle of view, and color shading occurs. Desirably, by setting the following conditional expression (5a) range, it becomes easy to achieve a higher-quality zoom lens.

1.0 <0r1 / fr <2.0 (5a)
Conditional expression (6) defines the difference between the maximum and minimum values during zooming for the (0r1 / fr) value of conditional expression (5). Regardless of which the upper and lower limits of conditional expression (6) are exceeded, the angle of the light ray incident on the color separation surface of the color separation element varies greatly due to zooming, and color shading occurs. Desirably, by setting the following conditional expression (6a) range, it becomes easy to achieve a higher quality zoom lens.

0.2 <Δ (0r1 / fr) <0.9 (6a)
As described above, when each element is set, when applied to an imaging device such as a TV camera, for example, the image quality and high quality that can sufficiently meet the demand when the number of pixels of the imaging device becomes twice or more, etc. A zoom lens can be obtained. In particular, the rear group can be driven to provide an aberration correction effect. At the same time, the drive can suppress the deterioration of the image quality due to diffraction in consideration of the change in the entrance pupil magnification of the zoom lens, and a high-quality and high-quality zoom lens can be obtained.

Next, the lens configuration of the zoom lens of each embodiment will be described.
[Example 1]
With reference to FIG. 1, the zoom lens of Example 1 will be described. Embodiment 1 is a zoom lens with a high zoom ratio that is mounted on a TV camera or the like. In order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, an aperture stop SP, and a rear group LR are provided. The rear group LR includes a third lens unit L3 having a positive refractive power, a fourth lens unit L4 having a positive refractive power, and a fifth lens unit L5 having a positive refractive power.

  In the present embodiment, the first lens unit L1 does not move during zooming from the wide-angle end to the telephoto end. The second lens unit L2 to the fifth lens unit L5 move. In this embodiment, although the zoom ratio is 11.4, the zoom lens has high resolution with little aberration fluctuation during zooming. The aperture stop SP moves while drawing a convex locus on the object side during zooming from the wide-angle end to the telephoto end.

  The first lens unit L1 includes a first a1 lens unit L1a1 that does not move during focusing, a first a2 lens unit L1a2 that moves during focusing, and a first b lens unit L1b that does not move during focusing. By moving a part of the first lens unit L1 to adjust the focus when the shooting distance changes, the zoom magnification does not change even when focusing from an infinite object to a close object. It has a simple structure.

  Both the third lens unit L3 to the fifth lens unit L5 constituting the rear group LR move along a locus that is convex toward the object side during zooming from the wide-angle end to the telephoto end. This prevents the field curvature from deteriorating in the intermediate zoom range.

  In the present embodiment, the third lens unit L3 has the maximum movement amount with respect to the zoom position at the wide-angle end in the rear group LR, and is −18.6 mm (− sign is toward the object side) at the zoom intermediate position. Represents movement). The maximum moving amounts of the other moving lens groups (L4, L5) are −12.3 mm and −11.0 mm, respectively, at the zoom intermediate position. For this reason, the values corresponding to the conditional expression (1) are 1.51 and 1.69.

  The value of conditional expression (2) regarding the movement of the second lens unit L2, the aperture stop SP, and the rear unit LR is 1.32. Accordingly, the relationship between the amount approximately equivalent to the magnification of the entrance pupil diameter and the zoom ratio is appropriately designed to suppress deterioration in image quality due to diffraction effects due to the F number becoming large (the lens system darkening). In this embodiment, the lens group corresponding to the lens group LX1 according to the conditional expression (4) is the fourth lens group L4, and the lens group corresponding to the lens group LX2 is the fifth lens group L5.

[Example 2]
With reference to FIG. 3, the zoom lens of Example 2 will be described. The second embodiment is a zoom lens with a high zoom ratio that is mounted on the same TV camera as the first embodiment. The zoom type is the same as in the first embodiment. That is, in order from the object side to the image side, the first lens unit L1 having a positive refractive power, the second lens unit L2 having a negative refractive power, an aperture stop SP, and a rear group LR are provided. The rear group LR includes a third lens unit L3 having a positive refractive power, a fourth lens unit L4 having a positive refractive power, and a fifth lens unit L5 having a positive refractive power.

  In Example 2, the first-b lens unit L1b includes three positive lenses. In Example 2, it is the third lens unit L3 that has the largest moving amount with respect to the zoom position at the wide-angle end in the rear group LR, and is −35.7 mm at the zoom intermediate position. The maximum moving amounts of the moving lens groups (L4, L5) are -22.1 mm and -11.6 mm, respectively, at the zoom intermediate position. For this reason, the values corresponding to the conditional expression (1) are 1.62 and 3.07. The value of conditional expression (2) regarding the movement of the second lens unit L2, the aperture stop SP, and the rear unit LR is 1.19.

  In this embodiment, the lens group corresponding to the lens group LX1 according to the conditional expression (4) is the fourth lens group L4, and the lens group corresponding to the lens group LX2 is the fifth lens group L5. Other configurations are the same as those in the first embodiment.

[Example 3]
With reference to FIG. 5, the zoom lens of Example 3 will be described. Example 3 is a zoom lens with a high zoom ratio that is mounted on a TV camera or the like. In order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, an aperture stop SP, and a rear group LR are provided. The rear group LR includes a third lens unit L3 having a negative refractive power, a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a positive refractive power, and a sixth lens unit L6 having a positive refractive power. Has been.

  In the present embodiment, the first lens unit L1 and the sixth lens unit L6 do not move during zooming from the wide-angle end to the telephoto end. Since all of the second lens unit L2 to the fifth lens unit L5 are movable, the zoom ratio is 11.4, and the lens has high resolution with little aberration fluctuation during zooming. The aperture stop SP moves to the image side during zooming from the wide-angle end to the telephoto end.

  During zooming from the wide-angle end to the telephoto end, the third lens unit L3 moves along a locus that is convex toward the object side. The fourth lens unit L4 and the fifth lens unit L5 move to the object side and perform zooming. This prevents the field curvature from deteriorating in the zoom intermediate range.

  In the present embodiment, the fifth lens unit L5 has the maximum movement amount with respect to the zoom position at the wide-angle end in the rear group LR, and is −12.6 mm at the zoom position at the telephoto end. And the maximum moving amount of the other moving lens units (L3, L4) is −7.2 mm at the zoom intermediate position of the third lens unit L3, and −5.0 mm at the zoom position of the telephoto end of the fourth lens unit L4. is there. For this reason, the values corresponding to the conditional expression (1) are 1.76 and 2.53. The value of conditional expression (2) regarding the movement of the second lens unit L2, the aperture stop SP, and the rear unit LR is 1.61.

  In this embodiment, the lens group corresponding to the lens group LX1 according to the conditional expression (4) is the third lens group L3, and the lens group corresponding to the lens group LX2 is the fourth lens group L4. Other configurations are the same as those in the first embodiment.

[Example 4]
A zoom lens according to Example 4 will be described with reference to FIG. Example 4 is a zoom lens with a high zoom ratio that is mounted on a TV camera or the like. In order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, an aperture stop SP, and a rear group LR are provided. The rear group LR includes a third lens unit L3 having a negative refractive power that moves integrally with the aperture stop SP, a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a positive refractive power, and a positive refractive power. The sixth lens unit L6 includes the sixth lens unit L6.

  In Example 4, the first lens unit L1 and the sixth lens unit L6 do not move during zooming from the wide-angle end to the telephoto end. Since all of the second lens unit L2 to the fifth lens unit L5 are movable, the zoom ratio is 11.4, and the lens has high resolution with little aberration fluctuation during zooming. The aperture stop SP moves together with the third lens unit L3 (same locus) during zooming, but may move independently (with a different locus).

  In the present embodiment, the fifth lens unit L5 has the largest amount of movement with reference to the zoom position at the wide-angle end in the rear group LR, and is −38.4 mm at the zoom position at the telephoto end. The maximum movement amount of the other moving lens groups (L3, L4) is −8.4 mm at the zoom intermediate position of the third lens group L3, and −4.0 mm at the zoom position of the telephoto end of the fourth lens group L4. is there.

  For this reason, the values corresponding to the conditional expression (1) are 4.59 and 9.6. The value of conditional expression (2) regarding the movement of the second lens unit L2, the aperture stop SP, and the rear unit LR is 1.17. Other points are the same as those in the third embodiment. The zoom lenses according to the first to fourth embodiments may be electrically corrected depending on the amount of distortion when combined with an image pickup apparatus including an image pickup element that converts an optical image formed on the light receiving surface into an electric signal. May be added.

  FIG. 9 is a schematic diagram of a main part of an imaging apparatus (television camera system) using the zoom lenses of Examples 1 to 4 as a photographing optical system. In FIG. 9, reference numeral 101 denotes any one of the zoom lenses according to the first to fourth embodiments. Reference numeral 124 denotes a camera. The zoom lens 101 can be attached to and detached from the camera 124. An imaging apparatus 125 is configured by attaching the zoom lens 101 to the camera 124. Reference numerals 114 and 115 denote driving mechanisms such as helicoids and cams for driving the respective lens groups in the optical axis direction.

  Reference numerals 116 and 117 denote motors (drive means) that electrically drive the drive mechanisms 114 and 115 and an aperture stop (not shown). Although not shown in FIG. 9, a detector such as an encoder, a potentiometer, or a photosensor for detecting the position of each lens group on the optical axis and the aperture diameter of the aperture stop is provided. Reference numeral 109 denotes a glass block corresponding to an optical filter or a color separation prism in the camera 124, and 110 denotes a solid-state image pickup device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the zoom lens 101.

  Reference numerals 111 and 122 denote CPUs that control various types of driving of the camera 124 and the zoom lens body 101. Thus, by applying the zoom lens of the present invention to a television camera, an imaging device having high optical performance is realized.

Numerical examples 1 to 4 corresponding to the first to fourth embodiments of the present invention will be shown below. In each numerical example, i indicates the order of the surfaces from the object side, r _i is the radius of curvature of the i-th surface from the object side, d _i is the i-th and i + 1-th distance from the object side, nd _i and νd _i are the refractive index and Abbe number of the i-th optical member. The three surfaces closest to the image are glass block surfaces.

  The focal length, the F number, and the angle of view (degree) indicate when the object is focused on infinity. BF is the back focus, and is indicated by the distance from the final surface (glass block surface) to the image surface. The aspheric shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the eccentricity, and A4, A6, A8, and A10 are aspherical surfaces. As a coefficient

It is expressed by the following formula. Further, for example, the display of “e-Z” means “10 ^−Z ”. Table 1 shows the relationship between the above-described conditional expressions and numerical values in the numerical examples.

[Numerical Example 1]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 196.578 3.80 1.77250 49.6 158.29
2 94.834 24.61 137.21
3 438.686 3.30 1.71300 53.9 136.73
4 186.532 24.38 131.05
5 -232.900 3.20 1.69680 55.5 129.54
6 387.879 0.20 129.26
7 218.577 15.33 1.84666 23.8 130.27
8 -1457.607 4.72 129.58
9 -500.097 8.63 1.49700 81.5 128.76
10 -206.143 0.15 128.31
11 -1725.295 22.35 1.51633 64.1 122.24
12 -109.692 3.60 1.69895 30.1 121.23
13 -225.917 20.26 122.96
14 212.315 3.80 1.74950 35.3 118.38
15 103.489 21.72 1.49700 81.5 115.66
16 -2744.339 0.20 115.58
17 180.844 19.12 1.43387 95.1 115.04
18 -242.755 0.20 114.35
19 130.297 8.56 1.43387 95.1 104.00
20 300.000 (variable) 102.70
21 88.254 1.80 1.77250 49.6 45.09
22 34.999 9.76 39.55
23 -57.822 1.80 1.59240 68.3 39.38
24 81.946 0.05 1.61937 19.2 37.74
25 50.827 8.82 37.42
26 -50.321 2.95 1.59240 68.3 37.62
27 -281.311 2.96 39.82
28 241.016 6.17 1.76182 26.6 42.33
29 -68.202 (variable) 42.77
30 (Aperture) ∞ (Variable) 27.54
31 * 191.537 2.83 1.49700 81.5 37.32
32 -1287.606 0.25 37.58
33 43.567 3.60 1.76182 26.6 38.55
34 60.603 0.65 37.91
35 69.534 2.00 1.77250 49.6 37.91
36 44.450 (variable) 37.03
37 487.924 6.05 1.61800 63.3 48.69
38 -92.839 0.20 48.92
39 1125.343 2.00 1.78590 44.2 48.31
40 48.424 11.25 1.49700 81.5 47.47
41 -114.983 (variable) 47.73
42 449.990 10.15 1.49700 81.5 47.40
43 -42.235 1.80 1.77250 49.6 47.22
44 * -479.326 0.20 48.47
45 74.188 12.40 1.43387 95.1 49.75
46 -54.538 (variable) 49.74
47 ∞ 50.00 1.69680 55.5 50.00
48 ∞ 19.00 1.51633 64.2 50.00
49 ∞ 16.56 50.00
Image plane ∞

Aspheric data 31st surface
K = 0.00000e + 000 A 4 = -9.57947e-007 A 6 = -6.53262e-011 A 8 = -2.00710e-013

44th page
K = 0.00000e + 000 A 4 = 4.28288e-007 A 6 = 2.77206e-010 A 8 = -5.06765e-015 A10 = 1.71241e-016

Various data Zoom ratio 11.54
Wide angle Medium telephoto focal length 10.21 56.31 117.88
F number 1.87 2.26 2.35
Half angle of view (degrees) 38.07 8.09 3.88
Statue height 8.00 8.00 8.00
Total lens length 555.0 555.0 555.0
BF 16.56 16.56 16.56

d20 1.30 97.55 121.61
d29 85.68 20.82 3.81
d30 57.75 7.75 2.75
d36 45.00 51.27 59.53
d41 0.55 1.90 0.55
d46 3.37 14.33 5.41

Entrance pupil position 103.83 266.12 431.95
Exit pupil position 72.11 210.91 189.06
Front principal point position 115.92 338.75 630.39
Rear principal point position 6.34 -39.77 -101.31

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position h12w h12t
1 1 116.22 188.13 125.10 57.13 -55.65 64.66
2 21 -39.17 34.31 0.18 -35.52
Aperture 30 ∞ 0.00 0.00 -0.00
3 31 354.31 9.33 -22.03 -26.24
4 37 145.35 19.50 7.55 -5.28
5 42 101.20 24.56 14.90 -1.95
GB 47 ∞ 69.00 21.00 -21.00

Single lens Data lens Start surface Focal length
1 1 -241.11
2 3 -457.65
3 5 -208.40
4 7 225.44
5 9 698.84
6 11 225.81
7 12 -309.00
8 14 -273.47
9 15 201.17
10 17 242.18
11 19 522.91
12 21 -76.20
13 23 -56.95
14 24 -216.23
15 26 -103.94
16 28 70.39
17 31 335.70
18 33 186.38
19 35 -165.24
20 37 126.71
21 39 -64.44
22 40 70.16
23 42 78.22
24 43 -60.06
25 45 74.62
26 47 0.00
27 48 0.00

[Numerical Example 2]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 360.683 3.80 1.77250 49.6 159.31
2 132.936 25.08 142.98
3 -704.073 3.30 1.71300 53.9 142.45
4 258.240 20.19 136.37
5 -300.943 3.20 1.62588 35.7 135.51
6 157.251 0.20 136.11
7 158.937 25.32 1.84666 23.8 136.13
8 -461.768 5.00 135.68
9 2118.389 17.23 1.49700 81.5 130.88
10 -191.980 0.50 129.33
11 299.127 24.14 1.49700 81.5 114.24
12 -137.356 3.60 1.75520 27.5 111.98
13 -12828.561 21.95 109.80
14 5312.248 11.20 1.49700 81.5 106.78
15 -194.111 0.20 106.76
16 175.191 8.44 1.43387 95.1 102.11
17 618.433 0.20 100.97
18 114.565 9.75 1.43387 95.1 96.57
19 300.000 (variable) 94.94
20 113.423 1.80 1.77250 49.6 44.83
21 * 30.375 11.64 38.36
22 -41.905 1.80 1.59240 68.3 37.99
23 124.415 0.05 1.61937 19.2 37.86
24 65.308 8.50 37.83
25 -51.938 2.95 1.59240 68.3 38.55
26 -74.830 0.11 40.55
27 208.353 7.11 1.76182 26.6 42.88
28 -74.430 (variable) 43.53
29 (Aperture) ∞ (Variable) 30.08
30 * 86.437 3.56 1.49700 81.5 36.84
31 940.026 1.01 36.80
32 251.463 3.81 1.76182 26.6 36.78
33 -170.719 0.10 36.67
34 -247.964 2.00 1.77250 49.6 36.57
35 110.037 (variable) 36.26
36 344.353 6.49 1.61800 63.3 45.78
37 -79.776 0.20 46.08
38 342.331 2.00 1.78590 44.2 45.41
39 43.115 10.37 1.49700 81.5 44.40
40 -170.980 (variable) 44.59
41 -201.201 8.60 1.49700 81.5 44.34
42 -36.930 1.80 1.77250 49.6 44.51
43 * -213.232 0.20 46.89
44 75.684 13.35 1.43387 95.1 49.34
45 -46.755 (variable) 49.55
46 ∞ 50.00 1.69680 55.5 50.00
47 ∞ 19.00 1.51633 64.2 50.00
48 ∞ 18.93 50.00
Image plane ∞

Aspheric data 21st surface
K = 1.01206e-002 A 4 = -1.40590e-006 A 6 = 2.61109e-010 A 8 = -4.46694e-012 A10 = 2.86456e-015

30th page
K = 0.00000e + 000 A 4 = -1.19779e-006 A 6 = -8.26351e-011 A 8 = -2.03449e-013

No. 43
K = 0.00000e + 000 A 4 = 9.39172e-007 A 6 = 5.23004e-010 A 8 = 1.54654e-013 A10 = 2.79735e-016

Various data Zoom ratio 11.54
Wide angle Medium Telephoto focal length 10.21 62.35 117.87
F number 1.87 2.05 2.19
Half angle of view (degrees) 38.07 7.31 3.88
Statue height 8.00 8.00 8.00
Total lens length 555.0 555.0 555.0
BF 18.93 18.93 18.93

d19 1.30 97.89 120.54
d28 104.78 7.54 3.81
d29 41.70 6.70 1.70
d35 45.34 58.94 60.11
d40 2.22 12.68 7.18
d45 1.00 12.59 2.98

Entrance pupil position 103.42 263.92 439.60
Exit pupil position 97.58 152.86 189.08
Front principal point position 114.96 355.29 639.13
Rear principal point position 8.71 -43.44 -98.93

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position h12w h12t
1 1 118.86 183.31 122.06 52.46 -53.06 66.18
2 20 -39.50 33.96 -1.90 -37.93
Aperture 29 ∞ 0.00 0.00 -0.00
3 30 354.20 10.48 -11.03 -17.23
4 36 125.85 19.06 5.12 -7.34
5 41 109.76 23.95 18.82 3.27
GB 46 ∞ 69.00 21.00 -21.00

Single lens Data lens Start surface Focal length
1 1 -274.53
2 3 -264.62
3 5 -164.58
4 7 142.32
5 9 355.06
6 11 192.94
7 12 -183.87
8 14 377.05
9 16 560.15
10 18 420.50
11 20 -54.21
12 22 -52.70
13 23 -222.02
14 25 -301.01
15 27 72.78
16 30 191.27
17 32 134.00
18 34 -98.42
19 36 105.42
20 38 -62.95
21 39 70.41
22 41 89.46
23 42 -58.08
24 44 68.88
25 46 0.00
26 47 0.00

[Numerical Example 3]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 192.538 3.80 1.69680 55.5 150.81
2 90.124 26.53 130.15
3 1137.046 3.30 1.69680 55.5 129.65
4 173.488 23.56 123.09
5 -211.400 3.20 1.69680 55.5 121.93
6 1107.320 0.20 122.61
7 227.918 13.31 1.72825 28.5 125.27
8 -830.254 2.34 125.56
9 -803.054 9.85 1.43387 95.1 125.84
10 -197.901 0.10 126.11
11 -91563.853 21.72 1.48749 70.2 125.09
12 -107.730 3.60 1.68893 31.1 124.97
13 -196.978 24.29 126.46
14 220.132 3.80 1.72342 38.0 115.22
15 100.029 20.24 1.49700 81.6 110.55
16 -4267.236 0.20 109.81
17 188.345 17.01 1.43387 95.1 108.68
18 -241.512 0.20 107.93
19 112.264 7.08 1.59240 68.3 98.03
20 187.523 (variable) 96.68
21 77.858 1.50 1.81600 46.6 39.87
22 34.542 7.32 35.73
23 -77.035 1.40 1.81600 46.6 35.47
24 50.165 7.11 33.92
25 -60.355 9.36 1.61340 44.3 34.17
26 -25.171 1.40 1.61800 63.4 35.57
27 -115.309 0.20 37.85
28 138.818 7.25 1.64769 33.8 38.91
29 -92.338 (variable) 39.37
30 (Aperture) ∞ (Variable) 24.28
31 -54.496 1.70 1.78800 47.4 32.30
32 76.811 3.92 1.84666 23.9 34.58
33 -603.198 (variable) 35.16
34 808.791 5.18 1.66672 48.3 38.35
35 -75.507 0.20 39.08
36 120.558 3.74 1.48749 70.2 39.91
37 3972.637 0.20 39.93
38 68.841 8.24 1.48749 70.2 40.01
39 -80.816 1.80 1.80400 46.6 39.50
40 302.876 (variable) 39.24
41 128.751 6.34 1.51633 64.2 40.55
42 -84.948 0.20 40.42
43 -141.016 2.00 1.83400 37.2 39.99
44 52.611 8.97 1.48749 70.2 39.64
45 -86.168 0.20 40.05
46 253.711 2.89 1.72342 38.0 40.12
47 -49498.685 (variable) 40.05
48 145.112 6.69 1.52249 59.8 39.57
49 -67.605 1.80 1.80 100 35.0 39.27
50 -657.975 0.20 39.26
51 42.238 5.18 1.48749 70.2 38.99
52 109.458 (variable) 38.22
53 ∞ 50.00 1.69680 55.5 40.00
54 ∞ 19.00 1.51633 64.2 40.00
55 ∞ 8.36 40.00
Image plane ∞

Various data Zoom ratio 11.54
Wide angle Medium Telephoto focal length 10.26 50.94 118.48
F number 1.93 2.16 2.82
Half angle of view (degrees) 37.93 8.93 3.86
Statue height 8.00 8.00 8.00
Total lens length 542.8 542.8 542.8
BF 8.36 8.36 8.36

d20 1.30 91.59 112.77
d29 65.65 8.19 2.81
d30 53.43 13.43 3.43
d33 5.21 10.70 1.58
d40 48.26 46.37 40.62
d47 0.70 4.27 13.34
d52 11.55 11.55 11.53

Entrance pupil position 99.15 239.19 388.19
Exit pupil position 57.46 134.78 774.18
Front principal point position 111.56 310.66 525.00
Rear principal point position -1.90 -42.57 -110.12

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position h12w h12t
1 1 105.99 184.34 120.71 54.38 -55.70 55.77
2 21 -39.54 35.54 -2.62 -38.21
Aperture 30 ∞ 0.00 0.00 -0.00
3 31 -81.82 5.62 -0.41 -3.50
4 34 67.51 19.36 0.48 -11.55
5 41 161.58 20.59 10.34 -3.35
6 48 126.41 13.88 1.72 -7.30
GB 53 ∞ 69.00 21.00 -21.00

Single lens Data lens Start surface Focal length
1 1 -246.92
2 3 -294.22
3 5 -254.50
4 7 246.87
5 9 602.33
6 11 221.23
7 12 -350.90
8 14 -256.85
9 15 196.96
10 17 246.86
11 19 456.22
12 21 -77.29
13 23 -37.05
14 25 63.92
15 26 -52.41
16 28 86.69
17 31 -40.23
18 32 80.69
19 34 103.82
20 36 254.96
21 38 77.66
22 39 -79.18
23 41 100.13
24 43 -45.73
25 44 68.46
26 46 348.93
27 48 89.23
28 49 -94.19
29 51 137.61
30 53 0.00
31 54 0.00

[Numerical Example 4]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 217.698 3.80 1.69680 55.5 137.13
2 96.671 20.28 121.26
3 1068.206 3.30 1.69680 55.5 120.76
4 173.708 21.05 114.88
5 -206.041 3.20 1.69680 55.5 113.59
6 886.631 0.20 113.80
7 232.202 13.45 1.72825 28.5 115.31
8 -605.827 2.75 115.72
9 -511.347 7.97 1.43387 95.1 115.88
10 -254.920 0.82 116.41
11 1119.132 22.40 1.48749 70.2 116.09
12 -99.326 3.60 1.68893 31.1 115.96
13 -168.718 20.26 117.64
14 250.021 3.80 1.72342 38.0 108.93
15 104.448 18.91 1.49700 81.6 107.00
16 -2007.328 0.20 107.01
17 172.890 16.78 1.43387 95.1 106.88
18 -263.576 0.20 106.31
19 106.273 7.08 1.59240 68.3 98.01
20 168.920 (variable) 96.56
21 83.337 1.50 1.81600 46.6 38.89
22 35.662 6.84 35.06
23 -78.070 1.40 1.81600 46.6 34.82
24 51.157 7.18 33.40
25 -57.496 8.35 1.61340 44.3 33.66
26 -28.487 1.40 1.61800 63.4 35.19
27 -123.714 0.20 37.15
28 181.047 8.43 1.64769 33.8 38.09
29 -79.192 (variable) 38.93
30 (Aperture) ∞ 3.47 33.45
31 -58.409 1.70 1.78800 47.4 33.62
32 86.486 5.95 1.84666 23.9 36.07
33 -993.488 (variable) 37.53
34 1613.898 5.75 1.66672 48.3 42.78
35 -68.571 0.20 43.52
36 140.977 7.00 1.48749 70.2 44.40
37 -624.247 0.20 44.41
38 81.405 10.27 1.48749 70.2 44.32
39 -73.594 1.80 1.80400 46.6 43.53
40 357.150 (variable) 43.33
41 122.357 8.88 1.51633 64.2 46.30
42 -101.302 0.20 45.96
43 -377.667 2.00 1.83400 37.2 45.22
44 54.869 9.61 1.48749 70.2 44.35
45 -117.115 (variable) 44.53
46 135.304 7.89 1.52249 59.8 44.02
47 -66.268 1.80 1.80 100 35.0 43.73
48 -347.126 0.20 43.77
49 50.736 5.71 1.48749 70.2 43.27
50 191.208 (variable) 42.53
51 ∞ 50.00 1.69680 55.5 40.00
52 ∞ 19.00 1.51633 64.2 40.00
53 ∞ 8.36 40.00
Image plane ∞

Various data Zoom ratio 11.54
Wide angle Medium Telephoto focal length 11.03 51.47 127.30
F number 1.93 1.85 2.30
Half angle of view (degrees) 35.96 8.83 3.60
Statue height 8.00 8.00 8.00
Total lens length 542.8 542.8 542.8
BF 8.36 8.36 8.36

d20 1.30 88.99 110.92
d29 113.91 17.86 2.81
d33 4.10 10.46 1.58
d40 53.52 47.80 19.11
d45 3.11 10.83 41.51
d50 11.55 11.56 11.54

Entrance pupil position 96.96 241.06 378.51
Exit pupil position 245.10 191.35 1209.18
Front principal point position 108.50 307.01 519.31
Rear principal point position -2.67 -43.11 -118.94

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position h12w h12t
1 1 110.51 170.04 114.33 50.28 -51.38 58.24
2 21 -38.63 35.30 -2.40 -37.29
3 30 -83.99 11.12 3.12 -4.54
4 34 67.99 25.21 0.34 -15.21
5 41 202.56 20.69 5.83 -8.17
6 46 110.70 15.60 3.15 -7.09
GB 51 ∞ 69.00 21.00 -21.00

Single lens Data lens Start surface Focal length
1 1 -252.81
2 3 -298.16
3 5 -239.65
4 7 232.07
5 9 1160.73
6 11 188.27
7 12 -358.12
8 14 -250.72
9 15 200.36
10 17 243.47
11 19 464.21
12 21 -77.49
13 23 -37.69
14 25 82.97
15 26 -60.22
16 28 86.16
17 31 -44.02
18 32 94.21
19 34 98.79
20 36 236.62
21 38 81.05
22 39 -75.75
23 41 108.80
24 43 -57.32
25 44 78.07
26 46 86.29
27 47 -102.54
28 49 139.80
29 51 0.00
30 52 0.00

L0 Zoom lens LR Rear group L1 1st lens group L1a 1a lens group L1a1 1a1 lens group L1a2 1a2 lens group L1b 1b lens group L2 2nd lens group L3 3rd lens group L4 4th lens group L5 5th lens Group L6 Sixth lens group SP Aperture stop

Claims (8)

In order from the object side to the image side, the first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, and a rear group including a plurality of lens groups. In the zoom lens in which the group is stationary and at least two lens groups of the second lens group and the rear group move,
The first lens group includes, in order from the object side to the image side, a first-a lens group having a negative refractive power and a first-b lens group having a positive refractive power, and the first-a lens group is formed from the object side to the image side. In order, the first a1 lens unit having a negative refractive power and the first a2 lens unit having a positive refractive power that moves upon focusing,
Of the rear group, the movement amount of the lens group having the maximum movement amount during zooming from the wide-angle end to the telephoto end is m1, the movement amount of the other lens groups of the rear group is mi, and the first lens group and the second lens group are the second group. The focal lengths of the lens groups are f1 and f2, respectively, and the principal point intervals of the first lens group and the second lens group at the wide-angle end and the telephoto end are h12w and h12t, respectively. The distances from the image side lens surface to the aperture stop are Sw and St, respectively, and the zoom ratio is Z.
Zp = {(Sw + f2) (f1 + f2-h12w)-(f2 ² )} / {(St + f2) (f1 + f2-h12t)-(f2 ² )}
When you leave
1.1 <m1 / mi <15
1.1 <Z / Zp <2.0
A zoom lens satisfying the following conditional expression: When the focal length of the first a2 lens group is f1a2,
1 <f1a2 / f1 <5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The rear group includes a lens group LX1 that moves along a locus convex to the object side during zooming from the wide-angle end to the telephoto end, and a lens group LX2 that moves adjacent to the lens group LX1, and the lens group LX2 moves during zooming. When the maximum distance between the lens group LX1 and the lens group LX2 is Lmax and the minimum distance is Lmin,
2 <Lmax / Lmin <10
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   4. The zoom lens according to claim 1, wherein the rear group includes three lens groups having a positive refractive power from the image side to the object side. 5. When the distance from the aperture stop to the front main plane position of the rear group is 0r1, the focal length of the rear group is fr, and the ratio (0r1 / fr) of the distance 0r1 to the focal length fr is the maximum and minimum over the entire zoom range. When the value difference is Δ (0r1 / fr),
0.9 <0r1 / fr <2.0
Δ (0r1 / fr) <1.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The rear group includes, in order from the object side to the image side, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power. The zoom lens according to any one of claims 1 to 5, wherein three lens groups, the fourth lens group, and the fifth lens group move.   The rear group includes, in order from the object side to the image side, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a sixth lens having a positive refractive power. 6. The zoom lens according to claim 1, further comprising a lens group, wherein the third lens group, the fourth lens group, and the fifth lens group move during zooming, and the sixth lens group does not move. The zoom lens according to claim 1.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.