JP2017003646A - Zoom lens and image capturing device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens which has an image capturing area where the lens switches from a circular fisheye mode to a diagonal fisheye mode, allows for capturing an image at an imaging angle of approximately a standard view angle at a maximum focal length, and easily provides high optical performance over an entire zoom range.SOLUTION: A zoom lens comprises a first lens group L1 having negative refractive power and a rear group LR having positive refractive power, and an image sensor has a rectangular image capturing area. When a focal length of the entire zoom lens system is at a minimum focal length, a maximum image height is less than half of a diagonal length of the image capturing area and an image of an object is not formed in a portion of the image capturing area. A focal length of the entire zoom lens system when the maximum image height is half the diagonal length of the image capturing area is defined as a first intermediate focal length. The maximum image height continuously increases from the minimum focal length to the first intermediate focal length. A focal length ft of the entire zoom lens system at the maximum focal length, an imaging half angle ωt of the entire zoom lens system at the maximum focal length, an image height Yw at the minimum focal length, and a length D corresponding to half the diagonal length of the image sensor are each set appropriately.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is suitable as an image pickup optical system used for an image pickup apparatus using an image pickup device such as a digital still camera, a video camera, a surveillance camera, an in-vehicle camera, and a broadcast camera. is there.

  In recent years, there has been a demand for a fish-eye zoom lens with a wide angle of view that can be easily picked up with few blind spots in an imaging optical system used for a surveillance camera, an in-vehicle camera, and the like. The fish-eye zoom lens is mainly intended to ensure a wide imaging angle of view by allowing distortion. For example, there is a method in which the image circle diameter is set with reference to the diagonal direction of the imaging element at the lens image formation position, and the total imaging field angle (2ω) at the diagonal of the imaging element is about 180 degrees (“diagonal fish” Called the "eye system").

  On the other hand, an image having a substantially circular shape is formed on the image pickup device of the image pickup device by adopting a method in which the entire image pickup view angle in the short side direction of the image pickup device is set to an image pickup view angle of about 180 degrees. There is a method for securing an imaging angle of view of about 180 degrees on the entire circumference (referred to as “all-around fisheye method”).

  Conventionally, zoom lenses that can select any fisheye method by zooming are known in order to select the whole fisheye method from the diagonal fisheye method in this way. (Patent Document 1). In addition, a fish-eye zoom lens with a relatively high zoom ratio that has an imaging half field angle of about 90 degrees at the shortest focal length (wide angle end) and can zoom to a standard imaging field angle at the telephoto end is known. (Patent Document 2).

JP2012-22109A JP 2012-194238 A

  In recent years, in imaging devices such as surveillance cameras and in-vehicle cameras, there is an increasing demand for fish-eye lenses using a circumferential fish-eye method that enables imaging with a small blind spot. However, the circumferential fish-eye method has problems that it cannot effectively use all the pixels of the image sensor, and that the enlargement magnification becomes small and the subject identification ability is insufficient. For this reason, imaging devices such as surveillance cameras and in-vehicle cameras have good optical performance in the entire range from the range including the circumferential fisheye method and the diagonal fisheye method to the longest focal length that is the standard imaging angle of view. There is a need for zoom lenses.

  In order to satisfy these requirements, the shape and size of the imaging area of the image sensor, the change in the imaging angle of view and the change in the maximum image height associated with zooming of the zoom lens should be set appropriately for the imaging area of the image sensor. Becomes important.

  The present invention has an imaging area that changes from an all-round fish-eye system to a diagonal fish-eye system, and can capture images with an imaging field angle of the standard field angle at the longest focal length, and has high optical performance over the entire zoom range. An object is to provide a zoom lens that can be easily obtained.

The zoom lens of the present invention is a zoom lens for forming a subject image formed on an image sensor,
In order from the object side to the image side, the first lens group having a negative refractive power and a rear group including a plurality of lens groups, the rear group includes a lens group having a positive refractive power, and from the shortest focal length When zooming to the longest focal length, the distance between adjacent lens groups changes,
The imaging area of the imaging element is rectangular, and when the focal length of the entire zoom lens system is the shortest focal length, the maximum image height is lower than half the diagonal length of the rectangular imaging area, and the imaging area There is an area where the subject image is not formed,
When the focal length of the entire zoom lens system when the maximum image height is half the diagonal length of the imaging region is the first intermediate focal length, the maximum image height is from the shortest focal length to the first intermediate focal length. Continuously increasing,
The focal length of the entire zoom lens system at the longest focal length is ft, the imaging half field angle of the entire zoom lens system at the longest focal length is ωt, the image height at the shortest focal length is Yw, and half the diagonal length of the imaging element. When the length of D is D
0.75 <D / ft × tan (ωt) <1.10
1.4 <D / Yw <2.6
It satisfies the following conditional expression.

  According to the present invention, there is an imaging region that changes from the all-round fish-eye method to the diagonal fish-eye method, and at the longest focal length, an image can be picked up with an image angle of view that is about the standard angle of view, and high optical performance in the entire zoom range A zoom lens with easy performance can be obtained.

Lens cross section at the shortest focal length in Example 1 (A), (B), (C) Aberration diagrams at the shortest focal length, the first intermediate focal length, and the longest focal length in Example 1. Lens cross-sectional view at the shortest focal length in Example 2 (A), (B), (C) Aberration diagrams at the shortest focal length, the first intermediate focal length, and the longest focal length in Example 2. Lens cross-sectional view at the shortest focal length in Example 3 (A), (B), (C) Aberration diagrams of Example 3 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens cross-sectional view at the shortest focal length in Example 4 (A), (B), (C) Aberration diagrams of Example 4 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens cross-sectional view at the shortest focal length in Example 5 (A), (B), (C) Aberration diagrams of Example 5 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens sectional drawing at the shortest focal length in Example 6 (A), (B), (C) Aberration diagrams of Example 6 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens cross section at the shortest focal length in Example 7 (A), (B), (C) Aberration diagrams of Example 7 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens cross section at the shortest focal length in Example 8 (A), (B), (C) Aberration diagrams at the shortest focal length, the first intermediate focal length, and the longest focal length in Example 8. Lens sectional view of Example 9 at the shortest focal length (A), (B), (C) Aberration diagrams of Example 9 at the shortest focal length, the first intermediate focal length, and the longest focal length Lens cross section at the shortest focal length in Example 10 (A), (B), (C) Aberration diagrams at Example 10 at the shortest focal length, the first intermediate focal length, and the longest focal length Schematic of image circle and image sensor at each zoom position of zoom lens of the present invention Schematic diagram of image circle of zoom lens of the present invention and image sensor Schematic diagram of main parts of an imaging apparatus of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is a zoom lens for forming a subject image on an image sensor. The imaging area of the imaging element is rectangular. The zoom lens includes, in order from the object side to the image side, a rear group having a plurality of lens groups including a first lens group having a negative refractive power and a lens group having a positive refractive power, and adjacent lens groups for zooming. The interval of changes.

  FIG. 1 is a lens cross-sectional view at the shortest focal length of the zoom lens according to Embodiment 1 of the present invention. 2A, 2B, and 2C are aberration diagrams of the zoom lens of Example 1 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. The first embodiment is a zoom lens having a zoom ratio of 5.00 and an F number of 1.60 to 3.50.

  FIG. 3 is a lens cross-sectional view at the shortest focal length of the zoom lens according to the second embodiment of the present invention. 4A, 4B, and 4C are aberration diagrams of the zoom lens of Example 2 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. The second embodiment is a zoom lens having a zoom ratio of 4.00 and an F number of 1.60 to 3.50.

  FIG. 5 is a lens cross-sectional view at the shortest focal length of the zoom lens according to Embodiment 3 of the present invention. 6A, 6B, and 6C are aberration diagrams of the zoom lens of Example 3 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. Example 3 is a zoom lens having a zoom ratio of 4.00 and an F number of 1.60 to 3.50.

  FIG. 7 is a lens cross-sectional view at the shortest focal length of the zoom lens according to the fourth exemplary embodiment of the present invention. 8A, 8B, and 8C are aberration diagrams of the zoom lens of Example 4 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. Example 4 is a zoom lens having a zoom ratio of 8.00 and an F number of 1.60 to 4.50.

  FIG. 9 is a lens cross-sectional view at the shortest focal length of the zoom lens according to Example 5 of the present invention. 10A, 10B, and 10C are aberration diagrams of the zoom lens of Example 5 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. Example 5 is a zoom lens having a zoom ratio of 10.00 and an F number of 1.60 to 4.90.

  FIG. 11 is a lens cross-sectional view at the shortest focal length of the zoom lens according to Example 6 of the present invention. FIGS. 12A, 12B, and 12C are aberration diagrams of the zoom lens of Example 6 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. Example 6 is a zoom lens having a zoom ratio of 5.00 and an F number of 1.60 to 3.50.

  FIG. 13 is a lens cross-sectional view at the shortest focal length of the zoom lens according to the seventh embodiment of the present invention. FIGS. 14A, 14B, and 14C are aberration diagrams of the zoom lens of Example 7 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. The seventh exemplary embodiment is a zoom lens having a zoom ratio of 5.00 and an F number of 1.60 to 3.50.

  FIG. 15 is a lens cross-sectional view at the shortest focal length of the zoom lens according to the eighth embodiment of the present invention. FIGS. 16A, 16B, and 16C are aberration diagrams of the zoom lens of Example 8 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. The eighth embodiment is a zoom lens having a zoom ratio of 4.99 and an F number of 1.60 to 3.50.

  FIG. 17 is a lens cross-sectional view at the shortest focal length of the zoom lens according to Example 9 of the present invention. 18A, 18B, and 18C are aberration diagrams of the zoom lens of Example 9 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. The ninth embodiment is a zoom lens having a zoom ratio of 4.99 and an F number of 1.60 to 3.50.

  FIG. 19 is a lens cross-sectional view at the shortest focal length of the zoom lens according to the tenth embodiment of the present invention. 20A, 20B, and 20C are aberration diagrams of the zoom lens of Example 10 at the shortest focal length, the first intermediate focal length, and the longest focal length, respectively. Example 10 is a zoom lens having a zoom ratio of 5.00 and an F number of 1.60 to 3.50.

  FIG. 21 is an explanatory diagram showing the relationship between the image circle and the image sensor at each zoom position in the zoom lens of the present invention. FIG. 22 is an explanatory diagram showing the relationship between the image circle and the image sensor in the zoom lens of the present invention. FIG. 23 is a schematic diagram of a main part of the imaging apparatus of the present invention.

  The zoom lens of each embodiment is an imaging optical system used for a surveillance camera. You may use the zoom lens of each Example for imaging devices, such as a video camera, a digital camera, a silver salt film camera, and a TV camera.

  In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear). In the lens cross-sectional view, L0 is a zoom lens. LR is a rear group including a lens unit having a positive refractive power and a plurality of lens units. When i is the order of the lens groups from the object side, Li indicates the i-th lens group. SP is an aperture stop. G is an optical block such as a filter. IP is the image plane. The image plane IP corresponds to an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor when a zoom lens is used as an imaging optical system of a digital camera, video camera, or surveillance camera.

  Further, when a zoom lens is used as an imaging optical system of a silver salt film camera, it corresponds to a film surface. In the zoom lens of each embodiment, the interval between adjacent lens groups changes during zooming. The arrows indicate the movement trajectory of each lens group during zooming from the shortest focal length to the longest focal length. An arrow related to the focus indicates the moving direction of the lens unit when focusing from infinity to a short distance.

  In the spherical aberration diagram, the solid line d indicates the d line (wavelength 587.6 nm), and the two-dot chain line g indicates the g line (wavelength 435.8 nm). In the astigmatism diagram, the dotted line ΔM is the d-line meridional image plane, and the solid line ΔS is the d-line sagittal image plane. The distortion aberration indicates a value at the d-line when the equal solid angle projection method is used as a reference. Lateral chromatic aberration is represented by the g-line. ω is an imaging half angle of view (degree), and Fno is an F number. In each embodiment, the shortest focal length and the longest focal length are zoom positions when the zooming lens groups are positioned at both ends of a range in which the zoom lens unit can move on the optical axis.

  The zoom lens of the present invention has a first lens group having a negative refractive power closest to the object side, and a rear group having a plurality of lens groups including a lens group having a positive refractive power closer to the image side than the first lens group. It is composed of LR. Then, zooming is performed by changing the interval between adjacent lens groups.

  As described above, zooming is performed by changing the interval between three or more lens groups, so that the standard is the longest focal length through the circular fisheye at the shortest focal length and the diagonal fisheye at the intermediate focal length. A high zoom ratio is achieved up to a wide angle of view. In addition to this, aberration fluctuations caused by large fluctuations in the imaging angle of view accompanying zooming are reduced well over the entire zoom range.

  In the zoom lens of the present invention, the maximum image height is smaller than the diagonal length of the rectangular imaging region when the focal length of the entire system is the shortest focal length. Then, there is an area where no subject image is formed in the periphery of the long side direction and the diagonal direction of the rectangular imaging area. Furthermore, the circumferential fish-eye method is adopted by making the maximum image height at the shortest focal length substantially coincide with the half length of the short side of the imaging region of the imaging device.

  In zooming from the shortest focal length to the longest focal length, the maximum image height continuously and monotonously increases to an intermediate focal length. The focal length of the entire zoom lens system in which the maximum image height is a length D that is half the diagonal length of the rectangular imaging region is defined as a first intermediate focal length. The zoom position at this time is a diagonal fisheye. Zooming is performed from this zoom position to the longest focal length.

  In the image pickup apparatus of the present invention, a subject image is picked up by a combination of a zoom lens and an image pickup element having a rectangular image pickup region.

  FIG. 21 is an explanatory diagram showing the relationship between the imaging element IM and the imaging region. The maximum image height Yw at the shortest focal length in FIG. 21A is shorter than the length D that is half the diagonal length of the rectangular imaging region SR, and the peripheral portion in the long side direction and the diagonal direction of the rectangular imaging region SR. There is a region BR where no subject image is formed. Furthermore, a circumferential fisheye is formed by making the maximum image height Yw at the shortest focal length substantially coincide with the half of the short side of the image sensor IM.

  Further, by zooming from the shortest focal length of FIG. 21A to the longest focal length of FIG. 21C, the maximum image height Y continuously increases monotonously to the intermediate focal length shown in FIG. . Here, the first intermediate focal length in which the maximum image height Y exceeds the half length D of the diagonal length of the rectangular imaging element IM is referred to as a first intermediate focal length. This zoom position becomes the diagonal fisheye. The zooming is performed from this zooming position to the longest focal length.

  21A, 21 </ b> B, and 21 </ b> C illustrate the relationship between the image circle diameter that changes with zooming and the imaging element IM, taking Example 1 as an example. As shown in FIG. 21 (A), at the shortest focal length, the short side length of the image sensor IM and the image circle diameter are substantially the same, resulting in a circular fisheye having an imaging field angle of 190 degrees in all directions. Yes. By increasing the image circle diameter by zooming from the shortest focal length, the diagonal length of the image sensor IM and the image circle diameter substantially coincide with each other at the first intermediate focal length shown in FIG. Is a diagonal fish-eye with an angle of view of 190 degrees.

  As shown in FIG. 21C, the diagonal length of the imaging element IM and the image circle diameter substantially coincide with each other even at the longest focal length, and the diagonal field angle is a standard imaging field angle of 55 degrees. . The radius of the image circle referred to here and the maximum image height Y at each focal length are substantially the same. However, the maximum image height Yt at the longest focal length may be smaller than the half length D of the diagonal length of the image sensor IM. This is because a combination with a so-called digital zoom that changes the effective imaging region by image processing can be applied.

In the zoom lens of the present invention, the focal length of the entire zoom lens system at the longest focal length is ft, the imaging half field angle of the entire zoom lens system at the longest focal length is ωt, and the imaging half field angle at the shortest focal length is ωw. The imaging half field angle at the first intermediate focal length is ωm, the image height at the shortest focal length is Yw, and the half length of the diagonal length of the rectangular imaging element IM is D. At this time,
0.75 <D / ft × tan (ωt) <1.10 (1)
1.4 <D / Yw <2.6 (2)
The following conditional expression is satisfied.

  In general, a fish-eye lens employs a projection system that satisfies the following expression, where Y is the image height, f is the focal length, and ω is the half angle of view.

Y = 2f × sin (ω / 2)... Solid angle projection method Y = 2f × tan (ω / 2)... Stereo projection method Y = f × ω. Equidistant projection method Y = fx sinω ... Orthographic projection method On the other hand, the zoom lens according to the present invention achieves a high zoom ratio as a fish-eye zoom lens, and has a central projection method represented by Y = f × tanω at the longest focal length. The standard angle of view of the lens. For this reason, if the distortion is large, an unnatural image is generated.

  FIG. 22 is a schematic diagram of an image circle picked up by the zoom lens according to the present invention and an image pickup surface of an image pickup element used in the image pickup apparatus. In the figure, IM is a rectangular imaging device having a diagonal length of 2 × D.

  Conditional expression (1) defines the ratio of the half length D of the imaging element IM to the ideal image height ft × tan (ωt) in the central projection method at the longest focal length. It defines a numerical range in which distortion does not become too large. Exceeding the lower limit value of conditional expression (1) is not preferable because barrel distortion becomes too large, resulting in an unnatural image. Exceeding the upper limit value of conditional expression (1) is not preferable because the pincushion type distortion becomes too large, resulting in an unnatural image.

  In FIG. 22, ISw represents an image circle at the shortest focal length, and the maximum image height Yw substantially matches the radius of the image circle ISw. Further, the maximum image height Yw substantially coincides with half DS of the short side length of the rectangular imaging element IM. ISm is an image circle at the first intermediate focal length, and the maximum image height Ym at the first intermediate focal length substantially coincides with the length D that is half the diagonal length of the imaging element IM.

  Conditional expression (2) defines the ratio of the length D which is half the diagonal length of the rectangular imaging element IM and the maximum image height Yw at the shortest focal length. There are various aspect ratios (vertical / horizontal ratios) of the rectangular imaging element IM, such as 3: 2 on the long side: 3: 2, 4: 3, and 16: 9. In the circumferential fish-eye state, the state in which the subject image is not formed in the peripheral portion of the rectangular imaging region has the smallest aspect ratio 1: 1 in which the lengths of the long side and the short side are equal, and the ratio increases. As a result, the area where the subject image is not formed becomes larger.

  In Examples 1 to 5 and 8 to 10, the imaging element IM has a ratio of the long side to the short side of 4: 3. In Example 6, the imaging element IM has a ratio of the long side to the short side of 1: 1. In Example 7, the imaging element IM has a ratio of the long side to the short side of 2.35: 1.

  When the lower limit value of conditional expression (2) is exceeded, the maximum image height Yw at the shortest focal length exceeds half DS of the short side length of the rectangular image pickup device IM. A blind spot is born in the part, which is not preferable. If the upper limit value of conditional expression (2) is exceeded, the area where no subject image is formed becomes too large in the periphery of the rectangular imaging area, which is not preferable because the resolving power of an image captured at the shortest focal length is low. Preferably, the numerical ranges of the conditional expressions (1) and (2) are set as follows.

0.78 <D / ft × tan (ωt) <1.05 (1a)
1.40 <D / Yw <2.57 (2a)
More preferably, the numerical ranges of conditional expressions (1a) and (2a) are set as follows.
0.785 <D / ft × tan (ωt) <1.00 (1b)
1.40 <D / Yw <2.56 (2b)

  With the above configuration, the imaging half field angle has a wide imaging field angle of 80 degrees or more at the shortest focal length. In addition, a zoom lens having a high zoom ratio and high optical performance can be obtained, which is easy to shoot by enlarging a subject at a shooting angle of view of the standard angle of view at the longest focal length. Furthermore, it is preferable to satisfy one or more of the following conditional expressions. The imaging half field angle at the shortest focal length is ωw, and the imaging half field angle at the first intermediate focal length is ωm.

  The lens unit Lmp having a positive refractive power included in the rear group LR is a lens unit that monotonically moves from the image side to the object side during zooming from the shortest focal length to the longest focal length, and has the largest movement amount during zooming. The focal length of the lens unit Lmp is fp, and the amount of movement of the lens unit Lmp during zooming from the shortest focal length to the longest focal length is mp. Here, the sign of the moving amount of the lens group is negative when the position is located on the object side at the longest focal length compared to the shortest focal length as a result of moving during zooming from the shortest focal length to the longest focal length. The position is positive.

  The first lens unit L1 includes, in order from the object side to the image side, a meniscus first negative lens with a convex surface facing the object side, and a meniscus second negative lens with a convex surface facing the object side. At this time, the curvature radii of the object-side and image-side lens surfaces of the first negative lens are R1a and R1b, respectively, and the curvature radii of the second negative lens and the object-side and image-side lens surfaces are R2a and R2b, respectively.

  In the first lens unit L1, when three negative lenses are successively arranged in order from the most object side to the image side, the focal lengths of the three negative lenses are fG1 and fG2 in order from the object side to the image side, respectively. , FG3. Let the focal length of the first lens group be f1. At this time, it is preferable to satisfy one or more of the following conditional expressions.

0.9 <ωm / ωw <1.1 (3)
80 ° <ωw <115 ° (4)
1.0 <| mp / fp | <4.0 (5)
1.0 <(R1a + R1b) / (R1a-R1b) <4.5 (6)
0.5 <(R2a + R2b) / (R2a−R2b) <3.5 (7)
0.8 <fG1 / fG2 <4.0 (8)
0.3 <fG2 / fG3 <1.5 (9)
0.2 <| f1 / fp | <0.7 (10)
0.4 <fp / ft <3.0 (11)

  Next, the technical meaning of each conditional expression described above will be described. In the zoom lens according to the present invention, the lens unit Lmp having a positive refractive power included in the rear unit LR is a main variable power lens unit. The zoom lens according to the present invention has a high zoom ratio and a bright F-number (F number), and further achieves downsizing of the entire system, so that the power arrangement of the main zoom lens unit and the movement of the lens unit Lmp during zooming are performed. The amount is set appropriately.

  Conditional expression (3) defines the ratio between the maximum half field angle ωw at the shortest focal length and the maximum half field angle ωm at the first intermediate focal length. If the upper limit value or lower limit value of conditional expression (3) is exceeded, the imaging angle of view may change too much due to scaling from the circumferential fisheye state to the diagonal fisheye state, and the subject at the periphery of the screen may not be displayed due to zooming. This is not preferable.

  Conditional expression (4) defines the maximum half angle of view at the shortest focal length. In particular, surveillance cameras and the like are often installed on the ceiling or wall surface, and are required to have a wide imaging angle of view of about 180 degrees as a fisheye lens in order to reduce blind spots. Exceeding the lower limit value of conditional expression (4) is not preferable because a blind spot is created and a desired subject cannot be imaged. If the upper limit value of conditional expression (4) is exceeded, the refractive power of the first lens unit having a negative refractive power will become too strong, increasing off-axis aberrations and achieving high zoom performance while achieving a high zoom ratio. It becomes difficult to obtain.

  Conditional expression (5) defines the ratio between the movement amount mp of the lens unit Lmp and the focal length fp of the lens unit Lmp during zooming from the shortest focal length to the longest focal length. If the lower limit of conditional expression (5) is exceeded and the amount of movement becomes small, it becomes difficult to achieve a high zoom ratio. Alternatively, the refractive power of the lens unit Lmp becomes too weak, and the amount of movement of the lens unit Lmp during zooming increases, making it difficult to reduce the size of the entire system.

  If the upper limit of conditional expression (5) is exceeded and the amount of movement becomes too large, it becomes difficult to downsize the entire system. Alternatively, the refractive power of the lens unit Lmp becomes strong, the amount of various aberrations increases, and it becomes difficult to obtain high optical performance.

  The zoom lens according to the present invention has an imaging angle of view of about 160 to 220 degrees in a circular fisheye to diagonal fisheye state, and the incident angle of light rays on the first lens unit L1 is substantially orthogonal to the optical axis. doing. As described above, the zoom lens according to the present invention achieves an imaging half field angle of 80 degrees or more at the shortest focal length, and the incident angle of the light beam to the first lens unit L1 with respect to the optical axis is large. It is necessary to greatly bend (refract) the incident light within the lens unit L1.

  On the other hand, if the light beam is bent too much, various aberrations related to the peripheral image height such as distortion and curvature of field increase in particular, so the lens configuration, lens shape, power arrangement, etc. in the first lens unit L1 are appropriately set. It becomes important to do.

  In the zoom lens according to the present invention, a negative meniscus lens having a convex surface facing the object side is arranged in order from the object side to the image side in order to bend the incident light greatly while maintaining high optical performance. Two sheets are arranged continuously. More preferably, one negative lens is also arranged on the image side.

  Conditional expression (6) defines the lens shape (shape factor) of the meniscus first negative lens included in the first lens unit L1. Conditional expression (7) defines the lens shape of the meniscus second negative lens included in the first lens unit L1. When the lower limit value of conditional expression (6) or conditional expression (7) is exceeded, the refractive power of both the first negative lens and the second negative lens becomes too strong, making it difficult to obtain high optical performance.

  When the upper limit value of conditional expression (6) or conditional expression (7) is exceeded, the values of the curvature radii of the object-side lens surface and the image-side lens surface in each of the first negative lens and the second negative lens are Get closer. As a result, the refractive power of the first negative lens and the second negative lens becomes too weak, making it difficult to obtain a wide imaging angle of view.

  Conditional expression (8) and conditional expression (9) are expressed by three negative lenses, a first negative lens, a second negative lens, and a third negative lens, which are sequentially arranged in order from the object side to the image side of the first lens unit L1. Defines the lens focal length ratio. Exceeding the lower limit of conditional expression (8), if the negative refractive power of the first negative lens is too strong, it becomes difficult to correct distortion, or the negative refractive power of the second negative lens is too weak and wide imaging. It becomes difficult to obtain the angle of view. If the upper limit of conditional expression (8) is exceeded and the negative refractive power of the first negative lens becomes too weak, it will be difficult to achieve a wide imaging angle of view, or the negative refractive power of the second negative lens will be strong. Thus, corrections such as distortion and curvature of field become insufficient, and it becomes difficult to obtain high optical performance.

  If the lower limit of conditional expression (9) is exceeded and the negative refracting power of the second negative lens is too strong, correction of distortion, curvature of field, etc. will be insufficient and it will be difficult to obtain high optical performance. Since the negative refractive power of the third negative lens is too weak, it is difficult to obtain a wide imaging angle of view. If the upper limit of conditional expression (9) is exceeded and the negative refractive power of the second negative lens is too weak, it becomes difficult to obtain a wide imaging angle of view, or the negative refractive power of the third negative lens is too strong. As a result, corrections such as coma and curvature of field become insufficient, making it difficult to obtain high optical performance.

  Conditional expression (10) defines the ratio of the focal length f1 of the first lens unit L1 having negative refractive power and the focal length fp of the lens unit Lmp having positive refractive power included in the rear group LR. If the lower limit of conditional expression (10) is exceeded and the negative refractive power of the first lens unit L1 becomes too strong (the absolute value of the negative refractive power becomes too large), the divergence of the incident light beam to the lens unit Lmp It is difficult to achieve a bright F-number because of too strong properties. Alternatively, the positive refractive power of the lens unit Lmp becomes too weak, and the amount of movement of the lens unit Lmp during zooming is too large, making it difficult to downsize the entire system.

  If the upper limit of conditional expression (10) is exceeded and the negative refractive power of the first lens unit L1 becomes too weak, the amount of movement of the first lens unit L1 becomes too large during zooming, making it difficult to downsize the entire system. become. Alternatively, the positive refractive power of the lens unit Lmp becomes too strong, and the amount of various aberrations increases, making it difficult to obtain high optical performance.

  Conditional expression (11) defines the ratio between the focal length fp of the lens unit Lmp having a positive refractive power and the focal length ft of the entire zoom lens system at the longest focal length. If the lower limit of conditional expression (11) is exceeded and the positive refractive power of the lens unit Lmp increases, the amount of various aberrations increases, making it difficult to obtain high optical performance. If the upper limit of conditional expression (11) is exceeded and the positive refractive power of the lens unit Lmp becomes weak, the amount of movement of the lens unit Lmp becomes too large during zooming, making it difficult to downsize the entire system.

  In each embodiment, it is preferable to set the numerical ranges of conditional expressions (3) to (11) as follows.

0.95 <ωm / ωw <1.05 (3a)
85 ° <ωw <115 ° (4a)
1.05 <| mp / fp | <3.50 (5a)
1.5 <(R1a + R1b) / (R1a-R1b) <4.0 (6a)
0.8 <(R2a + R2b) / (R2a−R2b) <3.0 (7a)
1.0 <fG1 / fG2 <3.5 (8a)
0.4 <fG2 / fG3 <1.3 (9a)
0.25 <| f1 / fp | <0.65 (10a)
0.5 <fp / ft <2.5 (11a)

More preferably, the numerical ranges of the conditional expressions (3a) to (11a) are set as follows.
0.97 <ωm / ωw <1.02 (2b)
90 ° <ωw <115 ° (3b)
1.15 <| mp / fp | <2.60 (5b)
1.8 <(R1a + R1b) / (R1a−R1b) <3.1 (6b)
1.3 <(R2a + R2b) / (R2a−R2b) <2.3 (7b)
1.3 <fG1 / fG2 <3.0 (8b)
0.5 <fG2 / fG3 <1.1 (9b)
0.29 <| f1 / fp | <0.57 (10b)
0.7 <fp / ft <2.1 (11b)

  In the zoom lens according to the present invention, the first lens unit L1 preferably includes three or more negative lenses and one or more positive lenses. As described above, the first lens unit L1 has three or more negative lenses. However, in particular, in order to correct axial chromatic aberration and lateral chromatic aberration, it may have one or more positive lenses. preferable. In the zoom lens according to the present invention, the lens unit Lmp, which is the main variable magnification lens unit, includes a lens having an aspheric lens surface and a cemented lens in which a positive lens and a negative lens are cemented in the lens unit Lmp. Is preferred.

  In the lens group Lmp, it is necessary to largely bend the diverging light incident from the first lens group having a negative refractive power into the convergent light, and particularly, a large spherical aberration is generated. Therefore, in order to correct spherical aberration, the lens unit Lmp preferably includes at least one aspherical lens. Moreover, it is preferable to have a cemented lens in which a positive lens and a negative lens are cemented in order to correct axial chromatic aberration and lateral chromatic aberration.

  In the zoom lens according to the present invention, the rear group LR includes, in order from the object side to the image side, a second lens group L2 having a positive refractive power, a third lens group L3 having a negative refractive power, and a fourth lens having a positive refractive power. It is preferable that the lens unit L4 is configured. It is preferable that the first lens unit L1, the second lens unit L2, and the third lens unit L3 move during zooming. In this way, by sequentially arranging the lens groups having different refractive powers of negative, positive, negative, and positive in order from the object side to the image side, the refractive power of each lens group becomes stronger and a high zoom ratio can be easily achieved. Has been achieved.

  The main zoom lens unit is the second lens unit L2, and the correction of the image plane position accompanying zooming is mainly performed by the first lens unit L1, and the third lens unit L3 moves independently to achieve high zoom. The zoom variation of various aberrations associated with the ratio is effectively suppressed, and high optical performance is obtained. In the zoom lens according to the present invention, the rear group LR includes, in order from the object side to the image side, a second lens group L2 having a positive refractive power, a third lens group L3 having a positive refractive power, and a fourth lens having a negative refractive power. It is preferable that the lens unit L4 includes a fifth lens unit L5 having a positive refractive power. Further, it is preferable that the first lens unit L1 to the fourth lens unit L4 move during zooming.

  The main zoom lens unit is the third lens unit L3. The correction of the image plane position accompanying zooming is mainly performed by the first lens unit L1 and the second lens unit L2, and the third lens unit L3 moves independently. As a result, the zoom fluctuation of various aberrations accompanying the increase in the zoom ratio is effectively suppressed, and high optical performance is achieved. Further, since the movement locus of the second lens unit L2 is slightly different from that of the first lens unit L1, the off-axis aberration on the shortest focal length side is corrected favorably and high optical performance is obtained.

  In the zoom lens according to the present invention, it is preferable that the rear group LR includes a second lens unit L2 having a positive refractive power and a third lens unit L3 having a positive refractive power in order from the object side to the image side. It is preferable that the first lens unit L1, the second lens unit L2, and the third lens unit L3 move during zooming.

  The main zoom lens unit is the second lens unit L2, and the correction of the image plane position accompanying zooming is mainly performed by the first lens unit L1, and the third lens unit L3 moves independently to achieve a high zoom ratio. The zoom fluctuation of various aberrations accompanying the shift to the zoom is effectively suppressed, and high optical performance is obtained. In the zoom lens according to the present invention, it is preferable that the rear group LR includes a second lens group L2 having a positive refractive power and a third lens group L3 having a negative refractive power in order from the object side to the image side. The first lens unit L1, the second lens unit L2, and the third lens unit L3 are preferably moved during zooming.

  The main zoom lens group is the second lens group L2, and the correction of the image plane position accompanying zooming is mainly handled by the first lens group L1, and the third lens group L3 moves independently to increase the zoom. This effectively suppresses zoom fluctuations of various aberrations associated with the lens and obtains high optical performance. More specifically, the zoom lens according to the present invention preferably has the following configuration.

  Next, the lens configuration of the zoom lens of each embodiment will be described. In the zoom lenses of Examples 1 to 7, the first lens unit L1 having a negative refractive power, the second lens unit L2 having a positive refractive power, and the third lens having a negative refractive power are sequentially arranged from the object side to the image side. The lens unit includes a group L3 and a fourth lens unit L4 having a positive refractive power. The rear group LR includes a second lens group L2, a third lens group L3, and a fourth lens group L4. Each lens unit moves so that the interval between adjacent lens units changes during zooming. As a result, by sharing the zoom ratio among the lens groups, the entire lens length is shortened and the front lens effective diameter is reduced while securing a sufficient zoom ratio.

  During zooming from the shortest focal length to the longest focal length, the first lens unit L1 moves along a locus convex to the image side, and the second lens unit L2 and the third lens unit L3 move to the object side. The fourth lens unit L4 is stationary. The aperture stop SP moves (integrally) along the same locus as the third lens unit L3.

  In Examples 1 to 7, a rear focus method in which focusing is performed by the third lens unit L3 is employed. A solid line 3a and a dotted line 3b relating to the third lens unit L3 in the lens cross-sectional view indicate movement trajectories accompanying zooming from the shortest focal length to the longest focal length when focusing at infinity and short distance, respectively. Further, when focusing from infinity to a short distance at the longest focal length, the third lens unit L3 is retracted to the image side as indicated by an arrow 3c in the lens cross-sectional view.

  In the zoom lens of Example 8, in order from the object side to the image side, the first lens unit L1 having a negative refractive power, the second lens unit L2 having a positive refractive power, the third lens unit L3 having a positive refractive power, and a negative lens unit. The lens unit includes a fourth lens unit L4 having a refractive power and a fifth lens unit L5 having a positive refractive power. The rear group LR includes the second lens group L2 to the fifth lens group L5.

  The distance between adjacent lens units changes during zooming. During zooming from the shortest focal length to the longest focal length, the first lens unit L1 and the second lens unit L2 move along a convex locus toward the image side, and the third lens unit L3 and the fourth lens unit L4 move toward the object side. The fifth lens unit L5 does not move. A solid line 4a and a dotted line 4b relating to the fourth lens unit L4 in the lens cross-sectional view indicate movement trajectories accompanying zooming from the shortest focal length to the longest focal length when focusing at infinity and short distance, respectively. When performing focusing from infinity to a short distance at the longest focal length, the fourth lens unit L4 is moved to the image side as indicated by an arrow 4c.

  The zoom lens according to the ninth exemplary embodiment includes, in order from the object side to the image side, a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, and a third lens unit L3 having a positive refractive power. Is done. The rear group LR includes a third lens group L3. The rear group LR includes a second lens group L2 and a third lens group L3. When zooming from the shortest focal length to the longest focal length, each lens unit moves as indicated by an arrow.

  Specifically, during zooming from the shortest focal length to the longest focal length, the first lens unit L1 moves along a locus convex to the image side, the second lens unit L2 monotonously moves to the object side, and the third lens unit L3 moves to the image side. The aperture stop SP moves (integrally) along the same locus as the second lens unit L2.

  An arrow 3a related to the third lens unit L3 indicates a movement locus during zooming from the shortest focal length to the longest focal length when focusing on an object at infinity. An arrow 3b indicates a movement locus during zooming from the shortest focal length to the longest focal length when focusing on a short-distance object. An arrow 3c relating to the third lens unit L3 indicates a moving direction during focusing from infinity to a short distance. In focusing from infinity to short distance, the third lens unit L3 moves to the object side.

  The zoom lens of Example 10 includes, in order from the object side to the image side, a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, and a third lens unit L3 having a negative refractive power. The The rear group LR includes a second lens group L2 and a third lens group L3. When zooming from the shortest focal length to the longest focal length, each lens unit moves as indicated by an arrow. Specifically, during zooming from the shortest focal length to the longest focal length, the first lens unit L1 moves along a locus convex to the image side, the second lens unit L2 monotonously moves to the object side, and the third lens unit L3 moves to the object side. The aperture stop SP moves (integrally) along the same locus as the second lens unit L2.

  An arrow 1a regarding the first lens unit L1 indicates a movement locus during zooming from the shortest focal length to the longest focal length when focusing at infinity. An arrow 1b indicates a movement locus during zooming from the shortest focal length to the longest focal length when focusing on a short distance. An arrow 1c relating to the first lens unit L1 indicates a moving direction during focusing from infinity to a short distance. In focusing from infinity to short distance, the first lens unit L1 moves to the object side.

  In each embodiment, the first lens unit L1 includes three or more negative lenses and one or more positive lenses. In each embodiment, the second lens unit L2 has a positive lens having both aspheric surfaces on the most object side and a cemented lens in which a negative lens and a positive lens are cemented. As a result, high optical performance is obtained over the entire zoom range. In each embodiment, a design assuming an equal solid angle projection method represented by Y = 2f × sin (ω / 2) is made. However, a projection method peculiar to a fish-eye lens such as the above-described three-dimensional projection method, and the like. The projection method may be used.

  As described above, according to the present invention, the entire system has a wide imaging half angle of view of 80 degrees or more at the shortest focal length, and can magnify the subject with an angle of view about the standard angle of view at the longest focal length. Is small, and a zoom lens having a bright F number, a zoom ratio, and high optical performance can be obtained.

  FIG. 23 is a schematic view of a main part of a surveillance camera using a zoom lens according to the present invention. Reference numeral 20 denotes a surveillance camera body, and 21 denotes an imaging optical system constituted by any of the zoom lenses described in the first to tenth embodiments. Reference numeral 22 denotes a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the imaging optical system 21.

  Next, numerical data corresponding to the first to tenth embodiments of the present invention will be shown. In each numerical data, i indicates the order of the optical surfaces from the object side. ri is the radius of curvature of the i-th optical surface (i-th surface), di is the distance between the i-th surface and the i + 1-th surface, and ndi and νdi are the refractions of the material of the i-th optical member with respect to the d-line, respectively. Shows rate and Abbe number. The two optical surfaces closest to the image side are glass materials such as a face plate. * Attached to the surface number indicates that the lens surface is aspherical.

  Further, K is the eccentricity, A4, A6, A8, A10, and A12 are aspherical coefficients, and the displacement in the optical axis direction at the position of the height h from the optical axis is x with respect to the surface vertex. At this time, the aspherical shape is expressed by the following equation.

x = (h ² / R) / [1+ [1− (1 + K) (h / R) ² ] ^1/2 ] + A4h ⁴ + A6h ⁶ + A8h ⁸ + A10h ¹⁰ + A12h ¹²
Is displayed. Where R is the paraxial radius of curvature. The display of “e-Z” means “10 ^−Z ”.

  In each embodiment, the back focus (BF) represents the distance from the surface closest to the image side to the image surface of the lens system excluding a glass block such as a parallel plate by an air-converted length. The total lens length is a value obtained by adding back focus (BF) to the distance from the front lens surface to the final lens surface. Fno is a numerical value related to the F-number and the half field angle (ω) relating to the imageable field angle in consideration of the amount of distortion. Table 1 shows the correspondence with the above-described conditional expressions in each numerical data.

[Example 1]
Unit mm

Surface data surface number rd nd νd
1 28.064 1.10 1.78800 47.4
2 11.648 4.71
3 38.228 0.75 1.78800 47.4
4 7.236 8.61
5 -19.301 0.45 1.75 500 52.3
6 18.322 0.15
7 16.294 1.66 1.95906 17.5
8 135.475 (variable)
9 (Aperture) ∞ 1.00
10 * 12.509 6.00 1.69350 53.2
11 * -43.880 2.24
12 36.329 0.40 1.84666 23.8
13 9.146 2.92 1.49700 81.5
14 -16.179 0.15
15 819.957 1.10 1.49700 81.5
16 -26.056 (variable)
17 -40.224 0.70 1.77250 49.6
18 184.665 (variable)
19 15.913 2.04 1.49700 81.5
20 -36.252 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = -1.38286e-001 A 4 = -7.49796e-005 A 6 = -3.15768e-007
A 8 = 1.88748e-009 A10 = 6.26009e-011

11th page
K = 0.00000e + 000 A 4 = 1.22542e-004 A 6 = -5.62573e-007

Various data Zoom ratio 5.00
Shortest 1st middle longest focal length 1.67 2.77 8.37
F number 1.60 1.85 3.50
Half angle of view (degrees) 95.22 94.96 27.52
Image height 2.40 4.00 4.00
Total lens length 68.02 58.97 63.93
BF 4.82 4.82 4.82

d 8 25.26 13.07 1.50
d16 1.50 3.77 8.49
d18 1.78 2.64 14.46

Zoom lens group data group Start surface Focal length
1 1 -4.81
2 9 11.92
3 17 -42.70
4 19 22.54

[Example 2]
Unit mm

Surface data surface number rd nd νd
1 30.125 1.40 1.83481 42.7
2 12.072 6.25
3 30.258 0.80 1.83481 42.7
4 7.021 9.74
5 -18.682 0.45 1.75 500 52.3
6 17.046 0.15
7 15.215 2.94 1.95906 17.5
8 140.545 (variable)
9 (Aperture) ∞ 1.00
10 * 12.429 5.87 1.69350 53.2
11 * -32.047 2.37
12 50.275 0.40 1.84666 23.8
13 8.936 2.34 1.49700 81.5
14 -22.072 0.15
15 51.822 1.14 1.49700 81.5
16 -20.144 (variable)
17 -53.135 0.70 1.77250 49.6
18 115.735 (variable)
19 30.306 1.71 1.49700 81.5
20 -23.347 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = -1.79267e-001 A 4 = -9.00830e-005 A 6 = -9.80669e-007
A 8 = 2.98779e-008 A10 = -7.83349e-010

11th page
K = 0.00000e + 000 A 4 = 1.22119e-004 A 6 = -1.43231e-006

Various data Zoom ratio 4.00
Shortest 1st middle longest focal length 1.50 2.46 5.98
F number 1.60 1.97 3.50
Half angle of view (degrees) 111.01 109.93 38.72
Image height 2.40 4.00 4.00
Total lens length 70.06 60.49 61.02
BF 4.82 4.82 4.82

d 8 24.13 11.82 1.50
d16 1.50 3.62 5.78
d18 1.53 2.14 10.84

Zoom lens group data group Start surface Focal length
1 1 -4.39
2 9 11.41
3 17 -47.06
4 19 26.82

[Example 3]
Unit mm

Surface data surface number rd nd νd
1 22.154 1.00 1.77250 49.6
2 11.089 3.12
3 25.416 0.70 1.77250 49.6
4 6.505 8.22
5 -15.443 0.40 1.72916 54.7
6 17.588 0.15
7 15.031 1.41 1.95906 17.5
8 74.562 (variable)
9 (Aperture) ∞ 1.00
10 * 11.626 5.81 1.69350 53.2
11 * -34.115 1.57
12 49.436 0.40 1.84666 23.8
13 9.584 2.49 1.49700 81.5
14 -13.770 0.15
15 -269.774 1.08 1.49700 81.5
16 -17.814 (variable)
17 -48.004 0.70 1.77250 49.6
18 53.579 (variable)
19 16.426 1.95 1.49700 81.5
20 -29.481 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = -6.03930e-001 A 4 = -6.92722e-005 A 6 = -1.14491e-006
A 8 = 6.40109e-008 A10 = -1.62662e-009

11th page
K = 0.00000e + 000 A 4 = 2.14069e-004 A 6 = -1.41998e-006

Various data Zoom ratio 4.00
Shortest first middle longest focal length 1.88 3.09 7.50
F number 1.60 1.99 3.50
Half angle of view (degrees) 81.05 80.99 30.71
Image height 2.40 4.00 4.00
Total lens length 58.02 51.38 54.52
BF 4.82 4.82 4.82

d 8 19.35 9.68 1.50
d16 1.50 3.51 7.12
d18 1.53 2.55 10.27

Zoom lens group data group Start surface Focal length
1 1 -4.78
2 9 10.44
3 17 -32.68
4 19 21.53

[Example 4]
Unit mm

Surface data surface number rd nd νd
1 38.178 1.60 1.78800 47.4
2 14.433 7.41
3 37.220 1.00 1.78800 47.4
4 8.622 11.38
5 -21.875 0.55 1.75 500 52.3
6 21.735 0.18
7 19.640 1.90 1.95906 17.5
8 163.886 (variable)
9 (Aperture) ∞ 1.00
10 * 11.916 6.00 1.69350 53.2
11 * -422.860 2.22
12 24.068 0.40 1.84666 23.8
13 8.682 3.45 1.49700 81.5
14 -16.004 0.15
15 374.184 1.04 1.49700 81.5
16 -78.545 (variable)
17 -90.808 0.70 1.77250 49.6
18 30.576 (variable)
19 16.079 2.08 1.49700 81.5
20 -33.506 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = 7.32309e-003 A 4 = -2.52328e-005 A 6 = 2.49313e-007
A 8 = -3.36977e-010 A10 = -5.62066e-012

11th page
K = 0.00000e + 000 A 4 = 1.64347e-004 A 6 = 6.47698e-007

Various data Zoom ratio 8.00
Shortest first intermediate longest focal length 1.54 2.55 12.30
F number 1.60 1.83 4.50
Half angle of view (degrees) 107.09 104.97 18.63
Image height 2.40 4.00 4.00
Total lens length 89.37 74.59 80.99
BF 4.82 4.82 4.82

d 8 39.01 21.44 1.50
d16 1.50 3.20 10.12
d18 2.30 3.38 22.81

Zoom lens group data group Start surface Focal length
1 1 -5.39
2 9 13.11
3 17 -29.54
4 19 22.17

[Example 5]
Unit mm

Surface data surface number rd nd νd
1 39.696 1.30 1.77250 49.6
2 13.243 4.05
3 24.861 0.90 1.77250 49.6
4 9.367 8.71
5 -24.039 0.65 1.69680 55.5
6 30.885 0.15
7 21.828 1.94 1.95906 17.5
8 80.313 (variable)
9 (Aperture) ∞ 1.00
10 * 10.840 5.97 1.69350 53.2
11 * 23.629 2.02
12 22.054 0.40 1.85478 24.8
13 9.602 4.23 1.49700 81.5
14 -14.229 0.15
15 14.108 1.54 1.49700 81.5
16 48.947 (variable)
17 -92.066 0.70 1.69680 55.5
18 14.722 (variable)
19 12.665 2.57 1.49700 81.5
20 -46.851 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = 2.01725e-002 A 4 = -1.22434e-005 A 6 = 1.06289e-007
A 8 = -8.40518e-009 A10 = 7.12164e-011

11th page
K = 0.00000e + 000 A 4 = 2.05184e-004 A 6 = 9.17735e-007

Various data Zoom ratio 10.00
Shortest first middle longest focal length 1.84 3.07 18.37
F number 1.60 1.84 4.90
Half angle of view (degrees) 82.00 80.99 12.44
Image height 2.40 4.00 4.00
Total lens length 95.02 76.59 80.56
BF 4.82 4.82 4.82

d 8 49.61 28.26 1.50
d16 1.50 2.38 8.32
d18 2.12 4.17 28.95

Zoom lens group data group Start surface Focal length
1 1 -7.39
2 9 13.03
3 17 -18.17
4 19 20.35

[Example 6]
Unit mm

Surface data surface number rd nd νd
1 31.302 1.30 1.78800 47.4
2 12.687 5.24
3 35.463 0.90 1.78800 47.4
4 7.891 9.33
5 -18.952 0.55 1.75 500 52.3
6 23.066 0.15
7 19.962 1.75 1.95906 17.5
8 455.674 (variable)
9 (Aperture) ∞ 1.00
10 * 14.477 5.55 1.69350 53.2
11 * -45.648 3.22
12 46.602 0.45 1.84666 23.8
13 10.603 3.14 1.49700 81.5
14 -18.163 0.15
15 247.748 1.21 1.49700 81.5
16 -28.226 (variable)
17 -51.679 0.80 1.77250 49.6
18 95.706 (variable)
19 15.297 2.66 1.49700 81.5
20 -38.203 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = 1.98402e-001 A 4 = -5.14881e-005 A 6 = 8.07605e-009
A 8 = 1.00915e-009 A10 = -6.08754e-012

11th page
K = 0.00000e + 000 A 4 = 9.74683e-005 A 6 = -2.01144e-009

Various data Zoom ratio 5.00
Shortest first middle longest focal length 1.94 2.74 9.71
F number 1.60 1.76 3.50
Half angle of view (degrees) 95.84 94.98 23.68
Image height 2.83 4.00 4.00
Total lens length 75.03 67.54 71.05
BF 4.82 4.82 4.82

d 8 27.47 17.71 1.50
d16 1.50 3.27 12.22
d18 3.16 3.67 14.43

Zoom lens group data group Start surface Focal length
1 1 -5.34
2 9 13.32
3 17 -43.34
4 19 22.35

[Example 7]
Unit mm

Surface data surface number rd nd νd
1 24.396 1.10 1.77250 49.6
2 11.101 4.55
3 41.771 0.75 1.77250 49.6
4 6.372 7.37
5 -20.443 0.45 1.69680 55.5
6 10.652 0.15
7 10.135 3.17 1.95906 17.5
8 29.037 (variable)
9 (Aperture) ∞ 1.00
10 * 15.418 5.98 1.69350 53.2
11 * -257.173 1.62
12 34.506 0.40 1.84666 23.8
13 10.648 2.25 1.49700 81.5
14 -16.962 0.15
15 68.193 1.24 1.49700 81.5
16 -14.000 (variable)
17 -37.064 0.70 1.77250 49.6
18 -93.359 (variable)
19 12.012 2.17 1.49700 81.5
20 -76.369 2.00
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.49
Image plane ∞

Aspheric data 10th surface
K = -4.36427e-001 A 4 = -1.60904e-004 A 6 = -1.70189e-006
A 8 = 1.03080e-008 A10 = -2.33625e-009

11th page
K = 0.00000e + 000 A 4 = 6.18458e-005 A 6 = -2.28778e-006

Various data Zoom ratio 5.00
Shortest First Middle Longest Focal Length 1.10 2.82 5.51
F number 1.60 2.30 3.50
Half angle of view (degrees) 94.90 94.97 42.60
Image height 1.57 4.00 4.00
Total lens length 69.03 55.03 59.61
BF 4.81 4.81 4.81

d 8 27.47 7.31 1.50
d16 1.50 5.97 7.08
d18 1.52 3.21 12.49

Zoom lens group data group Start surface Focal length
1 1 -4.04
2 9 11.28
3 17 -80.00
4 19 21.06

[Example 8]
Unit mm

Surface data surface number rd nd νd
1 28.936 1.10 1.78800 47.4
2 11.680 4.46
3 34.847 0.75 1.78800 47.4
4 7.299 8.22
5 -21.543 0.45 1.75 500 52.3
6 28.560 (variable)
7 27.485 0.45 1.49700 81.5
8 14.534 1.60 1.95906 17.5
9 49.301 (variable)
10 (Aperture) ∞ 1.00
11 * 12.493 6.00 1.69350 53.2
12 * -40.391 2.30
13 39.190 0.40 1.84666 23.8
14 9.077 2.96 1.49700 81.5
15 -14.975 0.15
16 440.811 1.05 1.49700 81.5
17 -32.689 (variable)
18 -29.587 0.70 1.77250 49.6
19 -305.083 (variable)
20 14.495 2.09 1.49700 81.5
21 -38.318 2.00
22 ∞ 2.00 1.51633 64.1
23 ∞ 1.50
Image plane ∞

Aspheric data 11th surface
K = -2.35887e-001 A 4 = -7.55418e-005 A 6 = -3.32982e-007
A 8 = 8.59163e-009 A10 = -1.45109e-010

12th page
K = 0.00000e + 000 A 4 = 1.12583e-004 A 6 = -6.22943e-007

Various data Zoom ratio 4.99
Shortest 1st middle longest focal length 1.67 2.76 8.32
F number 1.60 1.86 3.50
Half angle of view (degrees) 95.11 94.95 27.71
Image height 2.40 4.00 4.00
Total lens length 68.09 59.18 64.78
BF 4.82 4.82 4.82

d 6 0.50 0.56 0.62
d 9 25.26 13.04 1.50
d17 1.50 3.63 7.59
d19 1.66 2.76 15.90

Zoom lens group data group Start surface Focal length
1 1 -3.55
2 7 32.11
3 10 12.00
4 18 -42.46
5 20 21.44

[Example 9]
Unit mm

Surface data surface number rd nd νd
1 27.555 1.10 1.78800 47.4
2 11.384 4.43
3 30.855 0.75 1.78800 47.4
4 6.896 6.97
5 -24.295 0.45 1.75 500 52.3
6 14.538 0.14
7 12.958 1.77 1.95906 17.5
8 48.972 (variable)
9 (Aperture) ∞ 1.00
10 * 12.525 4.76 1.69350 53.2
11 * 144.132 3.54
12 31.445 0.40 1.84666 23.8
13 9.982 2.68 1.49700 81.5
14 -20.051 0.15
15 32.875 1.30 1.49700 81.5
16 -30.642 (variable)
17 -29.109 0.70 1.77250 49.6
18 -128.985 1.02
19 13.103 2.08 1.49700 81.5
20 -41.284 (variable)
21 ∞ 2.00 1.51633 64.1
22 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = -1.03170e-001 A 4 = -3.48328e-005 A 6 = -7.57643e-007
A 8 = 2.53453e-008 A10 = -2.98498e-010

11th page
K = 0.00000e + 000 A 4 = 1.11596e-004 A 6 = -2.20679e-007

Various data Zoom ratio 4.99
Shortest 1st middle longest focal length 1.64 2.74 8.17
F number 1.60 1.90 3.50
Half angle of view (degrees) 95.00 94.94 28.42
Image height 2.40 4.00 4.00
Total lens length 68.12 59.37 63.68
BF 6.21 5.74 4.82

d 8 26.49 14.07 1.50
d16 1.50 5.63 23.45
d20 3.39 2.92 2.00

Zoom lens group data group Start surface Focal length
1 1 -4.90
2 9 13.00
3 17 32.53

[Example 10]
Unit mm

Surface data surface number rd nd νd
1 33.691 1.30 1.80 400 46.6
2 10.001 4.91
3 44.432 0.80 1.78800 47.4
4 7.981 3.64
5 -432.818 0.50 1.75500 52.3
6 14.102 1.26
7 14.377 2.36 1.95906 17.5
8 38.724 (variable)
9 (Aperture) ∞ 1.00
10 * 9.716 2.98 1.55332 71.7
11 * -33.063 2.59
12 34.349 1.53 1.49700 81.5
13 -16.775 0.40 1.88300 40.8
14 42.341 0.13
15 11.276 1.61 1.49700 81.5
16 -30.055 0.40 1.91082 35.3
17 11.924 0.25
18 12.868 1.89 1.69680 55.5
19 -12.785 (variable)
20 * 42.920 0.80 1.85135 40.1
21 * 35.080 (variable)
22 ∞ 2.00 1.51633 64.1
23 ∞ 1.50
Image plane ∞

Aspheric data 10th surface
K = -8.83459e-002 A 4 = -1.14811e-004 A 6 = 5.57176e-007
A 8 = 2.19466e-009

11th page
K = 2.36941e + 000 A 4 = 6.74315e-005 A 6 = 1.67148e-006
A 8 = -1.66281e-009

20th page
K = 0.00000e + 000 A 4 = -1.30255e-003 A 6 = -1.07107e-006
A 8 = -1.06843e-006 A10 = 1.84286e-008 A12 = 2.99759e-009

21st page
K = 0.00000e + 000 A 4 = -1.09110e-003 A 6 = 5.67614e-006
A 8 = -1.31367e-006 A10 = 5.79101e-008 A12 = 2.23959e-009

Various data Zoom ratio 5.00
Shortest First Middle Longest Focal Length 1.71 2.77 8.56
F number 1.60 1.89 3.50
Half angle of view (degrees) 89.74 90.21 26.73
Image height 2.40 4.00 4.00
Total lens length 70.01 57.03 52.22
BF 6.21 8.44 20.10

d 8 33.11 17.98 1.47
d19 1.67 1.59 1.63
d21 3.39 5.62 17.28

Zoom lens group data group Start surface Focal length
1 1 -5.79
2 9 11.67
3 20 -236.70

L0 Zoom lens LR Rear group L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group

Claims (14)

A zoom lens for forming a subject image formed on an image sensor,
In order from the object side to the image side, the first lens group having a negative refractive power and a rear group including a plurality of lens groups, the rear group includes a lens group having a positive refractive power, and from the shortest focal length When zooming to the longest focal length, the distance between adjacent lens groups changes,
The imaging area of the imaging element is rectangular, and when the focal length of the entire zoom lens system is the shortest focal length, the maximum image height is lower than half the diagonal length of the rectangular imaging area, and the imaging area There is an area where the subject image is not formed,
When the focal length of the entire zoom lens system when the maximum image height is half the diagonal length of the imaging region is the first intermediate focal length, the maximum image height from the shortest focal length to the first intermediate focal length Increases continuously,
The focal length of the entire zoom lens system at the longest focal length is ft, the imaging half field angle of the entire zoom lens system at the longest focal length is ωt, the image height at the shortest focal length is Yw, and the diagonal length of the imaging element. When half of the length is D,
0.75 <D / ft × tan (ωt) <1.10
1.4 <D / Yw <2.6
A zoom lens satisfying the following conditional expression: When the imaging half field angle of the entire zoom lens system at the shortest focal length is ωw and the imaging half field angle of the entire zoom lens system at the first intermediate focal length is ωm,
0.9 <ωm / ωw <1.1
80 ° <ωw <115 °
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The lens unit having a positive refractive power included in the rear group moves monotonically toward the object side during zooming from the shortest focal length to the longest focal length, and the focal length of the positive refractive power lens group is fp, which is the shortest focal length. When the amount of movement of the lens unit having the positive refractive power during zooming from the distance to the longest focal length is mp,
1.0 <| mp / fp | <4.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The first lens group includes, in order from the object side to the image side, a meniscus first negative lens having a convex surface facing the object side, and a meniscus second negative lens having a convex surface facing the object side. The zoom lens according to any one of claims 1 to 3. When the radius of curvature of the object-side and image-side lens surfaces of the first negative lens is R1a and R1b, respectively, and the radius of curvature of the object-side and image-side lens surfaces of the second negative lens are R2a and R2b, respectively.
1.0 <(R1a + R1b) / (R1a-R1b) <4.5
0.5 <(R2a + R2b) / (R2a-R2b) <3.5
The zoom lens according to claim 4, wherein the following conditional expression is satisfied. The first lens group has three negative lenses successively in order from the object side to the image side, and the focal lengths of the three negative lenses are fG1, fG2, and fG3 in order from the object side to the image side, respectively. And when
0.8 <fG1 / fG2 <4.0
0.3 <fG2 / fG3 <1.5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first lens unit is f1, and the focal length of the positive refractive power lens unit included in the rear unit is fp,
0.2 <| f1 / fp | <0.7
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the positive refractive power lens group included in the rear group is fp,
0.4 <fp / ft <3.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   9. The lens unit having positive refractive power included in the rear group includes a lens having an aspherical lens surface and a cemented lens in which a positive lens and a negative lens are cemented. The zoom lens according to claim 1.   The first lens group moves during zooming, the rear group moves in order from the object side to the image side, a second lens group having positive refractive power that moves during zooming, and a third lens having negative refractive power that moves during zooming. The zoom lens according to any one of claims 1 to 9, wherein the zoom lens includes a fourth lens group having a positive refractive power.   The first lens group moves during zooming, the rear group moves in order from the object side to the image side, a second lens group having positive refractive power that moves during zooming, and a third lens having positive refractive power that moves during zooming. 10. The zoom lens according to claim 1, wherein the zoom lens includes a group, a fourth lens group having a negative refractive power that moves during zooming, and a fifth lens group having a positive refractive power.   The first lens group moves during zooming, the rear group moves in order from the object side to the image side, a second lens group having positive refractive power that moves during zooming, and a third lens having positive refractive power that moves during zooming. The zoom lens according to claim 1, comprising a group.   The first lens group moves during zooming, the rear group moves in order from the object side to the image side, a second lens group having positive refractive power that moves during zooming, and a third lens having negative refractive power that moves during zooming. The zoom lens according to claim 1, comprising a group.   An image pickup apparatus comprising: the zoom lens according to claim 1; and an image pickup element that receives an image formed by the zoom lens.