Lens device and image pickup device

Abstract

A lens device and an imaging device having the same are provided. The lens device is detachable from an imaging device main body having a dichroic prism, and includes a storage unit that stores correction data for correcting color shading of image data obtained by imaging an image formed by the zoom lens via the dichroic prism of the imaging device main body, and a communication unit that transmits the correction data to the imaging device main body. The correction data has correction values set for each combination of a zoom state, a focus state, and an aperture state of the zoom lens. The zoom lens includes a first lens group including a focus group, disposed at a position closest to an object side, and not moved during zooming, a plurality of moving lens groups moved during zooming, and a final lens group disposed at a position closest to an image side, and not moved during zooming.

Description

Technical Field

[0001] The present invention relates to a lens device and a camera device. Background Technology

[0002] Previously, there were camera devices described in the following patent document 1.

[0003] Patent Document 1: International Publication No. 2018 / 168214

[0004] Previously, dichroic prisms were known to separate light beams into colors, such as three-plate dichroic prisms that separate light into the three primary colors of blue, green, and red. In camera devices, when such three-plate dichroic prisms are used to separate camera beams into colors, a phenomenon known as color shading sometimes occurs where the vertical hue of the captured image differs. Summary of the Invention

[0005] The present invention provides a lens device that facilitates the correction of color shadows and a camera device having the lens device.

[0006] The lens device according to a first aspect of the present invention includes a zoom lens, wherein the zoom lens comprises: a first lens group including a focusing group that moves during focusing and is positioned closest to the object side, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the spacing between them and adjacent lens groups during zooming; and a final lens group positioned closest to the image side and fixed relative to the image plane during zooming. The lens device is detachable from a camera body having a dichroic prism and includes: a storage unit for storing information for correcting errors caused by the camera body. The image data obtained by taking a picture of the image formed by the zoom lens using a dichroic prism is color shading correction data; and the communication unit sends the correction data to the main body of the imaging device. The correction data has correction values ​​set for each combination of zoom state, focus state and aperture state of the zoom lens at a specific image height. When the focal length and maximum half angle of view of the zoom lens in each zoom state are set to f and ω respectively, and the unit of f is set to mm, the specific image height is defined by 0.49×f×tanω. The lens device satisfies the following conditional expression (1):

[0007] 1.5mm<0.49×f×tanω<5mm (1).

[0008] The lens device of the second aspect of the present invention includes a zoom lens, wherein the zoom lens includes: a first lens group, including a focusing group that moves during focusing and is positioned closest to the object side, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the interval between them and adjacent lens groups during zooming; and a final lens group that is positioned closest to the image side and is fixed relative to the image plane during zooming. The lens device can be attached to and detached from a camera device body having a dichroic prism, and includes: a storage unit that stores correction data for correcting color shading of image data obtained by the camera device body through which an image formed by the zoom lens is captured by the dichroic prism; and a communication unit that sends the correction data to the camera device body. The correction data has correction values ​​set for each combination of zoom state, focus state, and aperture state of the zoom lens. When the number of zoom states, the number of focus states, and the number of aperture states in each combination are set to Nz, Nf, and Na, respectively, the lens device satisfies the following conditional expressions (2) and (3):

[0009] 0.05≤Nf / (Nz×Na)≤0.3 (2)

[0010] 8≤(Nz×Nf) / Na≤256 (3).

[0011] In the lens device of the second method, it is preferable to set the focal length and maximum half angle of view of the zoom lens in each zoom state to f and ω respectively, and set the unit of f to mm, and the correction value is a value of a specific image height defined by 0.49×f×tanω, and the lens device satisfies the following conditional expression (1):

[0012] 1.5mm<0.49×f×tanω<5mm (1).

[0013] When the number of zoom states, focus states, and aperture states in each group are set to Nz, Nf, and Na respectively, the lens device described above preferably satisfies the following conditional expression (4):

[0014] 256≤Nz×Nf×Na≤2048 (4).

[0015] The preferred method is as follows: With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and f in mm, the correction value is the value defined by 0.49 × f × tanω at a specific image height. The ray incident on the image plane at a specific image height, where the angle between the upper and lower rays is bisected, is defined as the intermediate ray. The focal length when focusing on an infinity object at the telephoto end of the zoom lens is set to ft. The focal length when focusing on an infinity object at the wide-angle end of the zoom lens is set to fw. The distance from the image plane to the exit pupil of the intermediate ray when focusing on an infinity object is set to Dexp. The sign of Dexp is based on the image plane, with the image-side distance set positive and the object-side distance set negative. Therefore, Dexp is negative at the wide-angle end and positive at the telephoto end. Dexp becomes the focal length of the zoom lens at infinity at fw × (ft / fw). 0.6 The above and fw × (ft / fw) 0.9 Within the following range.

[0016] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, one or more but no more than three lens groups that move by changing the interval between them and adjacent lens groups during zooming, and a final lens group with positive refractive power.

[0017] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second and third lens groups move by changing their intervals.

[0018] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, and fourth lens groups move by changing the spacing between them and the adjacent lens groups.

[0019] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, and fourth lens groups move by changing the spacing between them and the adjacent lens groups.

[0020] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the interval between them and the adjacent lens groups.

[0021] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the spacing between them and the adjacent lens groups.

[0022] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the interval between them and the adjacent lens groups.

[0023] The lens device described above can be configured to include: an EX group, which can be inserted and removed relative to the optical path of a zoom lens and the focal length can be changed by insertion and removal; and an insertion / removal detection unit, which detects the insertion / removal status and sets a correction value for each insertion / removal status.

[0024] When the open F-number for focusing on an infinity object at the telephoto end of the zoom lens is set to FNot, the focal length for focusing on an infinity object at the telephoto end of the zoom lens is set to ft, and the focal length for focusing on an infinity object at the wide-angle end of the zoom lens is set to fw, the lens device described above preferably satisfies the following condition (5):

[0025] 0.03<FNot / (ft / fw)<0.3 (5).

[0026] When the focal length of the lens group with the strongest negative refractive power among the lens groups that move during zooming in the zoom lens is set to fn, and the focal length of the zoom lens when focusing on an object at infinity at the telephoto end is set to ft, the lens device described above preferably satisfies the following conditional expression (6):

[0027] -0.4<fn / ft<-0.02 (6).

[0028] The first lens group of the zoom lens can be configured such that, from the object side to the image side, it consists of a first subgroup A with negative refractive power that is fixed relative to the image plane during focusing, a first subgroup B with positive refractive power that moves along the optical axis during focusing, and a first subgroup C whose interval with the first subgroup B changes during focusing.

[0029] When the back focal length of the zoom lens in terms of air distance is set to Bfw, the focal length when the zoom lens is focused on an infinity object at the wide-angle end is set to fw, and the maximum half angle of view when the zoom lens is focused on an infinity object at the wide-angle end is set to ωw, the lens device described above preferably satisfies the following condition (7).

[0030] 4<Bfw / (fw×tanωw)<10 (7).

[0031] When the focal length and maximum half angle of view of the zoom lens in each zoom state are set to f and ω respectively, and the unit of f is set to mm, the correction value is the value at a specific image height defined by 0.49×f×tanω. When the ray incident on the image plane of the zoom lens at a specific image height is defined as the ray that bisectes the angle between the upper ray and the lower ray, the focal length when the zoom lens is focused on an infinity object at the wide-angle end is set to fw, the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an infinity object at the wide-angle end is set to Dexpw, and when an optical component without refractive power is arranged between the image plane and the exit pupil position of the intermediate ray, Dexpw is calculated using the air equivalent distance for the optical component. The lens device described above preferably satisfies the following condition (8):

[0032] 4<|Dexpw / fw|<360 (8).

[0033] The preferred method is as follows: when the focal length and maximum half angle of view of the zoom lens in each zoom state are set to f and ω respectively, and the unit of f is set to mm, the correction value is the value of a specific image height defined by 0.49×f×tanω. When the zoom lens is focused on an object at infinity, in the entire zoom area, the exit pupil position of the principal ray of the specific image height is located on the image side closer than the image plane.

[0034] The camera device of the present invention includes a lens device and a camera device body as described above. The camera device body includes: a dichroic prism; an imaging element for capturing an image formed by a zoom lens; and a processing unit for correcting the color and shadow of the image data based on correction data sent from the lens device.

[0035] In addition, the terms "composed of" and "composed of" in this specification mean that, in addition to the constituent elements listed, it may also include lenses that do not substantially have refractive power, as well as optical elements other than lenses such as apertures, filters and cover glass, and mechanism parts such as lens flanges, lens barrels, imaging elements and hand shaking correction mechanisms.

[0036] In this manual, "a group with positive refractive power" means that the group as a whole has positive refractive power. Similarly, "a group with negative refractive power" means that the group as a whole has negative refractive power. "A lens with positive refractive power" has the same meaning as "positive lens." "A lens with negative refractive power" has the same meaning as "negative lens." In this manual, "a lens group" and "focusing group" are not limited to a structure consisting of multiple lenses; they can also be a structure consisting of only one lens.

[0037] In this specification, the number of lens elements refers to the number of individual lenses that constitute the lens. For example, the number of lenses in a combined lens, which is formed by joining multiple individual lenses of different materials, is expressed as the number of individual lenses constituting the combined lens. However, a compound aspherical lens (i.e., a lens (e.g., a spherical lens) and an aspherical film formed on the lens are integrated and function as a single aspherical lens) is used as a single lens and not considered a combined lens. Unless otherwise specified, the symbols for refractive power and surface shapes related to lenses including aspherical surfaces use the symbols and surface shapes of the paraxial region.

[0038] In this manual, the "focal length" used in the conditional expressions refers to the paraxial focal length. Unless otherwise specified, the values ​​used in the conditional expressions are based on the d-line when the zoom lens is focused on an object at infinity.

[0039] The “d-line,” “C-line,” “F-line,” and “g-line” described in this specification are bright lines. The wavelength of the d-line is considered to be 587.56 nm, the wavelength of the C-line is considered to be 656.27 nm, the wavelength of the F-line is considered to be 486.13 nm, and the wavelength of the g-line is considered to be 435.84 nm.

[0040] -Invention Effects-

[0041] According to the present invention, a lens device that facilitates the correction of color shadows and a camera device having the lens device can be provided. Attached Figure Description

[0042] Figure 1 This is a functional structure diagram of the camera device according to the first embodiment.

[0043] Figure 2 This is a structural cross-sectional view of an example of a zoom lens.

[0044] Figure 3 It means Figure 2 Cross-sectional views of the beam and structure of the zoom lens in various states.

[0045] Figure 4 This is a schematic diagram of an example of a three-plate dichroic prism.

[0046] Figure 5 This is a diagram representing an example of corrected data.

[0047] Figure 6 This is a graph representing an example of the number of states contained in the correction data.

[0048] Figure 7 It is a diagram used to illustrate the intermediate light rays.

[0049] Figure 8 yes Figure 7 A magnified view of region A.

[0050] Figure 9 This is a flowchart representing an example of an action.

[0051] Figure 10 This is a flowchart representing another example of an action.

[0052] Figure 11 This is a graph showing the relationship between focal length and Dexp.

[0053] Figure 12 This is a functional structure diagram of the camera device according to the second embodiment.

[0054] Figure 13 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 1.

[0055] Figure 14 These are aberration diagrams of the zoom lens in Example 1.

[0056] Figure 15 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 2.

[0057] Figure 16 These are aberration diagrams of the zoom lens in Example 2.

[0058] Figure 17 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 3.

[0059] Figure 18 These are aberration diagrams of the zoom lens in Example 3.

[0060] Figure 19 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 4.

[0061] Figure 20 These are aberration diagrams of the zoom lens in Example 4.

[0062] Figure 21 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 5.

[0063] Figure 22 These are aberration diagrams of the zoom lens in Example 5.

[0064] Figure 23 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 6.

[0065] Figure 24 These are aberration diagrams of the zoom lens in Example 6.

[0066] Figure 25 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 7.

[0067] Figure 26 These are aberration diagrams of the zoom lens in Example 7.

[0068] Figure 27 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 8.

[0069] Figure 28 These are aberration diagrams of the zoom lens in Example 8.

[0070] Figure 29 This is a cross-sectional view and a diagram showing the movement trajectory of the zoom lens in Embodiment 9.

[0071] Figure 30 These are aberration diagrams of the zoom lens in Example 9.

[0072] Symbol Explanation

[0073] 1-Zoom lens, 10-Lens assembly, 12-Focus detection unit, 14-Zoom detection unit, 16-Aperture detection unit, 20-Storage unit, 22-Correction data, 30-Communication unit, 40-Mount, 50-Camera device body, 60-Dial prism, 61-First prism component, 61B-Blue light transmission filter, 62-Second prism component, 62R-Red light transmission filter, 63-Third prism component, 63G-Green light transmission filter, 64-First optical filter, 65-Second optical filter, 68-Imaging element, 70-Processing unit, 80-Communication unit, 90-Display unit, 100-Camera device, 200-Camera device, 201-Zoom lens, 218-Insertion / removal detection unit, 220-Storage unit, 222-Correction Data, A-Region, EX-EX Group, G1-First Lens Group, G1A-First A Subgroup, G1B-First B Subgroup, G1C-First C Subgroup, G2-Second Lens Group, G3-Third Lens Group, G4-Fourth Lens Group, G5-Fifth Lens Group, GE-Final Lens Group, L-Incident Beam, L11~L59-Lens, LB-Blue Light, LG-Green Light, LR-Red Light, P1-Plot Point, P6-Plot Point, P7-Plot Point, P8-Plot Point, Pexpw-Exit Pupil Position, Ry1-Upper Ray, Ry2-Lower Ray, Ry3-Intermediate Ray, Sim-Image Plane, St-Aperture Stop, Ys-Specific Image Height, Z-Optical Axis, ωm-Maximum Half Angle of View, ωt-Maximum Half Angle of View, ωw-Maximum Half Angle of View. Detailed Implementation

[0074] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0075] [First Embodiment]

[0076] Figure 1 The diagram shows a functional structure of a camera device 100 according to the first embodiment of the present invention. The camera device 100 is, for example, a broadcast camera. The camera device 100 includes a lens assembly 10 and a camera device body 50. The lens assembly 10 is detachable from the camera device body 50 and can be mounted to the camera device body 50 via a bayonet 40 provided on the camera device body 50.

[0077] The lens assembly 10 includes a zoom lens 1 that captures an image of a subject (not shown). The camera assembly main body 50 includes a dichroic prism 60 and an imaging element 68. When the lens assembly 10 is mounted on the camera assembly main body 50, the camera assembly main body 50 can capture the image formed by the zoom lens 1 through the dichroic prism 60 via the imaging element 68, and generate image data through this capture.

[0078] [Structure of the lens assembly]

[0079] In addition to the zoom lens 1, the lens assembly 10 also includes a focus detection unit 12, a zoom detection unit 14, an aperture detection unit 16, a storage unit 20, and a communication unit 30.

[0080] Zoom lens 1 functions as a camera lens, capturing an image of the subject. Figure 1 The concept shows a zoom lens 1. Figure 2 The diagram shows a cross-sectional view of the zoom lens 1 at its wide-angle end. Figure 2 The example shown corresponds to the zoom lens of Embodiment 1 described later. Figure 3 The middle shows Figure 2 The structural cross-sectional views of zoom lens 1 under various zoom states. Figure 3 In the image, the upper section labeled "Wide" shows the wide-angle end, the middle section labeled "Middle" shows the intermediate focal length end, and the lower section labeled "Tele" shows the telephoto end. Figure 3 The image also shows beams, including an on-axis beam at the wide-angle end with a maximum half-angle angle ωw, an on-axis beam at the intermediate focal length with a maximum half-angle angle ωm, and an on-axis beam at the telephoto end with a maximum half-angle angle ωt. Figure 2 and Figure 3 In the image, the left side is the object side, the right side is the image side, and the image is focused on an object at infinity.

[0081] exist Figure 3 The diagram schematically illustrates a dichroic prism 60 positioned between the zoom lens 1 and the image plane Sim. In this example, the dichroic prism 60 comprises not only prism components but also filters that reflect or transmit light of specific wavelengths. The detailed structure of the dichroic prism 60 will be described later.

[0082] The zoom lens 1 includes a first lens group G1 positioned closest to the object, multiple movable lens groups that move along the optical axis Z by changing the spacing between them and adjacent lens groups during zooming, and a final lens group GE positioned closest to the image. Zooming is achieved by moving the movable lens groups. During zooming, the first lens group G1 and the final lens group GE remain fixed relative to the image plane Sim. By keeping the lens groups closest to the object and image plane Sim stationary during zooming, changes in the center of gravity during zooming can be suppressed. This structure is suitable for a dynamic image camera lens used in a camera optical system with a three-plate dichroic prism, and it is beneficial for correcting color shading.

[0083] An aperture stop St is disposed inside the zoom lens 1. The aperture stop St has an opening with a variable aperture size. By changing the aperture size of the aperture stop St, the amount of light passing through the zoom lens 1 changes, thereby changing the F-number of the zoom lens 1. The change in aperture size can be performed by the user or configured to be performed in conjunction with zoom.

[0084] As an example, Figure 2 The zoom lens 1 is configured as follows: From the object side to the image side, the zoom lens 1 consists of the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the final lens group GE. The first lens group G1 consists of 8 lenses, L11 to L18, from the object side to the image side. The second lens group G2 consists of 1 lens, L21. The third lens group G3 consists of 5 lenses, L31 to L35, from the object side to the image side. The fourth lens group G4 consists of 2 lenses, L41 to L42, from the object side to the image side. The final lens group GE consists of 9 lenses, L51 to L59, from the object side to the image side. Figure 2 The aperture stop St shown does not represent its size or shape, but rather its position along the optical axis. Figure 2 In the examples, the second lens group G2, the third lens group G3, and the fourth lens group G4 are examples of the "moving lens group" of the present invention. Figure 2 In the image, below the lens group corresponding to the moving lens group, curved arrows indicate the approximate movement trajectory of each moving lens group when zooming from the wide-angle end to the telephoto end.

[0085] The first lens group G1 is configured to include a focusing group. The focusing group moves along the optical axis Z during focusing. Focusing of the zoom lens 1 is achieved by moving the focusing group. By using a lens positioned closer to the object side than the moving lens group that moves during zooming, and which remains stationary during zooming, zooming and focusing can be made independent. Therefore, a lens structure suitable for use with moving images can be established.

[0086] Figure 2 In the example, the first lens group G1, from the object side to the image side, consists of a first subgroup G1A with negative refractive power that is fixed relative to the image plane Sim during focusing; a first subgroup G1B with positive refractive power that moves along the optical axis Z during focusing; and a first subgroup G1C whose interval with the first subgroup G1B changes during focusing. That is, in Figure 2 In the example, subgroup G1B of the first subgroup corresponds to the focus group. Figure 2 In the image, a double arrow pointing horizontally is shown below the group corresponding to the focus group. Figure 2In the example, subgroup 1A G1A is composed of lenses L11 to L13, subgroup 1B G1B is composed of lenses L14 to L16, and subgroup 1C G1C is composed of lenses L17 to L18.

[0087] The movement of the focusing group, the movement of the moving lens group, and the change in the opening amount of the aperture stop St are performed, for example, by a drive unit (not shown) including actuators such as linear motors, stepper motors, or voice coil motors.

[0088] The focus detection unit 12 detects the position of the optical axis of the focus group and uses this detected position to detect the focus state of the zoom lens 1. The focus state can be represented, for example, by the distance between the subject being focused on by the zoom lens 1 and the zoom lens 1. The focus detection unit 12 is configured, for example, to include an encoder such as a photoelectric circuit breaker and / or a magnetic sensor.

[0089] The zoom detection unit 14 detects the position of the optical axis of each moving lens group and uses the detected position to detect the zoom state of the zoom lens 1. Zoom state refers to magnification state. Wide-angle and telephoto states each constitute one zoom state. The zoom state can be represented, for example, by the overall focal length of the zoom lens 1. The zoom detection unit 14 is configured, for example, to include an encoder such as a photoelectric circuit breaker and / or a magnetic sensor.

[0090] The aperture detection unit 16 detects the opening amount of the aperture stop St and uses the detected opening amount to detect the aperture state of the zoom lens 1. The aperture state can be represented, for example, by the effective F-number of the zoom lens 1. The aperture detection unit 16 is configured, for example, to include an encoder such as a photoelectric circuit breaker and / or a magnetic sensor.

[0091] Storage unit 20 stores correction data 22. Correction data 22 is data used to correct color shading in image data obtained by capturing images using the camera body 50. The correction data 22 will be described in detail later. Storage unit 20 is, for example, composed of non-volatile memory such as flash memory.

[0092] The communication unit 30 communicates with the camera device body 50. With the lens device 10 mounted on the bayonet 40, the lens device 10 is electrically connected to the camera device body 50. Through this electrical connection, the communication unit 30 within the lens device 10 and the communication unit 80 within the camera device body 50 are able to communicate with each other. The communication unit 30 transmits the various states of the lens device 10 and the correction data 22 to the camera device body 50. Furthermore, "transmitting the correction data 22" is not limited to transmitting the entire correction data; it also includes transmitting only a portion of the correction data 22.

[0093] In the lens assembly 10, various parts are controlled and various processes are performed by a processor (not shown). This processor is, for example, a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0094] [Structure of the main body of the camera device]

[0095] In addition to having a dichroic prism 60 and an imaging element 68, the main body of the camera device 50 also has a processing unit 70, a communication unit 80 and a display unit 90.

[0096] The dichroic prism 60 is a prism that decomposes an incident light beam into beams of multiple colors and emits them outwards. In a camera device that uses three solid-state imaging elements for taking pictures—red, green, and blue—the camera beam is configured such that the dichroic prism 60 decomposes the camera beam into the three primary colors of red, green, and blue before it is incident on the solid-state imaging elements for each color.

[0097] Figure 4 A schematic structural diagram of an example of a dichroic prism 60 is shown. Figure 4 The dichroic prism 60 is a three-plate dichroic prism that splits the incident light beam L into three colors; it is an optical component without refractive power. The dichroic prism 60 has three prism components arranged sequentially from the light incident side: a first prism component 61, a second prism component 62, and a third prism component 63. A first optical filter 64 for color separation is formed at the interface between the first prism component 61 and the second prism component 62, and a second optical filter 65 for color separation is formed at the interface between the second prism component 62 and the third prism component 63.

[0098] exist Figure 4 In the dichroic prism 60, the first optical filter 64 is tilted to allow the incident light beam L to be incident at a predetermined angle, and is composed of an optical multilayer film that reflects blue light LB and transmits green light LG and red light LR. The second optical filter 65 is tilted relative to the first optical filter 64 at a predetermined angle, and is composed of an optical multilayer film that reflects red light LR and transmits green light LG. The optical multilayer films constituting the first optical filter 64 and the second optical filter 65 are films made by alternately stacking two or more optical films with different refractive indices.

[0099] A blue light transmission filter 61B, which allows only blue light LB to pass through, is provided on the light-emitting surface of the first prism component 61. A red light transmission filter 62R, which allows only red light LR to pass through, is provided on the light-emitting surface of the second prism component 62. A green light transmission filter 63G, which allows only green light LG to pass through, is provided on the light-emitting surface of the third prism component 63.

[0100] After the incident beam L is incident on the first prism component 61, it is reflected in the first optical filter 64, and blue light LB, green light LG, and red light LR are transmitted. The blue light LB reflected by the first optical filter 64 is totally internally reflected at the incident surface of the first prism component 61 and then emitted through the blue light transmission filter 61B toward a blue light solid-state imaging element (not shown).

[0101] The red light LR transmitted through the first optical filter 64 is reflected in the second optical filter 65 and emitted through the red light transmission filter 62R toward a red light solid-state imaging element (not shown). The green light LG transmitted through the first optical filter 64 is transmitted through the second optical filter 65 and emitted through the green light transmission filter 63G toward a green light solid-state imaging element (not shown).

[0102] In addition, Figure 4 For ease of understanding, the incident beam L toward the dichroic prism 60 is schematically shown with three arrows traveling in the horizontal direction. However, since the actual imaging beam passes through the zoom lens 1, the imaging beam incident on the dichroic prism 60 includes not only light rays perpendicular to the incident surface, but also light rays incident at various angles of incidence.

[0103] Typically, optical multilayer films exhibit angle-of-incident dependence; the larger the angle of incidence, the more the spectral characteristics tend to shift towards shorter wavelengths. Furthermore, the larger the angle of incidence, the lower the transmittance. Therefore, the amount of light reflected or transmitted differs depending on whether the light incident at a high angle of incidence or at a low angle of incidence. Since the first optical filter 64 and the second optical filter 65 are composed of optical multilayer films, the light passing through the dichroic prism 60, according to the aforementioned angle-of-incident dependence, produces a phenomenon known as "color shading" where the light has different hues in the vertical direction of the captured image. Additionally, in this specification, "vertical direction of the image" refers to the direction perpendicular to the optical axis.

[0104] In particular, green light LG is separated by passing through two optical filters, the first optical filter 64 and the second optical filter 65. Therefore, compared to blue light LB and red light LR, the angular dependence of the amount of green light LG is stronger. As a result, for example, green increases while red and blue decrease at the periphery of the captured image. In particular, green light has a stronger effect on brightness; areas with more green light transmission are brighter, while areas with less green light are dimmer. This is the cause of the phenomenon known as "brightness shadows," where brightness differs in the vertical direction of the image.

[0105] In the main body 50 of the imaging device, the imaging beam transmitted through the dichroic prism 60 is incident on the imaging element 68. The imaging surface of the imaging element 68 is positioned at the image plane (Sim) of the zoom lens 1. The imaging element 68 captures the image formed by the zoom lens 1, generates image data through this capture, and outputs it to the processing unit 70. As the imaging element 68, for example, a solid-state imaging element such as a CCD (Charge-Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) can be used.

[0106] The processing unit 70 processes the signal output from the imaging element 68 to generate output image data. Furthermore, when generating the output image data, the processing unit 70 performs color and shadow correction processing on the image data based on the correction data 22 sent from the lens device 10 and acquired via the communication unit 80.

[0107] The communication unit 80 communicates with the communication unit 30 of the lens assembly 10. The correction data 22 sent from the lens assembly 10 to the camera body 50 via the communication unit 30 is received by the communication unit 80 and sent to the processing unit 70.

[0108] The display unit 90 displays the output image data generated by the processing unit 70. The display unit 90 is, for example, a liquid crystal monitor.

[0109] The main body 50 of the camera device is configured to include an operation unit (not shown) for receiving user input. The operation unit may consist of, for example, a zoom button, a release button, a dial, a cross-shaped or control wheel type selection button, and a touch panel provided on the display.

[0110] Within the main body 50 of the camera device, various components are controlled and various processes are executed by a processor (not shown). This processor may be, for example, a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The processing unit 70 may be configured as part of this processor.

[0111] [Correction Data]

[0112] The correction data 22 has correction values ​​set for various combinations of zoom, focus, and aperture states of the zoom lens 1. That is, the correction data 22 has multiple combinations of zoom, focus, and aperture states, and sets a corresponding correction value for each combination. This structure helps to keep the size of the correction data 22 compact.

[0113] The correction data 22 can be stored as table data. As an example, in... Figure 5 The image shows an example of correction data 22 stored as table data. Figure 5 The correction data 22 has correction values ​​v1, v2, v3, ... set for each combination of zoom states z1, z2, ..., focus states foc1, foc2 and aperture states a1, a2.

[0114] In order to suppress the size of the correction data 22 while appropriately obtaining the effect of color shading correction, it is preferable to satisfy at least one of the following conditional expressions (2), (3) and (4). Here, the number of zoom states in each group of combinations of the correction data 22 is set as Nz, the number of focus states is set as Nf, and the number of aperture states is set as Na.

[0115] 0.05≤Nf / (Nz×Na)≤0.3 (2)

[0116] 8≤(Nz×Nf) / Na≤256 (3)

[0117] 256≤Nz×Nf×Na≤2048 (4)

[0118] By ensuring that the corresponding value of conditional expression (2) is not below the lower limit, the number of focus states in the correction data 22 can be ensured, thus preventing undercorrection when correcting color shading caused by changes in focus state. By ensuring that the corresponding value of conditional expression (2) is not above the upper limit, the proportion of the number of focus states in the correction data 22 will not become too large, thus preventing undercorrection when correcting color shading caused by changes in zoom state and aperture state.

[0119] To obtain better properties, the lower limit of condition (2) is more preferably set to 0.0625, further preferably 0.1, and even more preferably 0.125. To obtain better properties, the upper limit of condition (2) is more preferably set to 0.25. For example, it is more preferable to satisfy condition (2) instead of condition (2), further preferably to satisfy condition (2-2), and even more preferably to satisfy condition (2-3).

[0120] 0.0625≤Nf / (Nz×Na)≤0.25 (2-1)

[0121] 0.1≤Nf / (Nz×Na)≤0.25 (2-2)

[0122] 0.125≤Nf / (Nz×Na)≤0.25 (2-3)

[0123] By ensuring that the corresponding value of conditional expression (3) is not below the lower limit, the proportion of aperture states in the correction data 22 will not become too large, thus making it easy to prevent undercorrection when correcting color shading caused by changes in zoom and focus states. By ensuring that the corresponding value of conditional expression (3) is not above the upper limit, the number of aperture states in the correction data 22 can be ensured, thus making it easy to prevent undercorrection when correcting color shading caused by changes in aperture states.

[0124] To obtain better properties, the lower limit of condition (3) is more preferably set to 16, more preferably 20, more preferably 24, and more preferably 32. To obtain better properties, the upper limit of condition (3) is more preferably set to 128, and more preferably 64. For example, it is more preferable to satisfy condition (3) instead of condition (3), more preferably to satisfy condition (3-2), more preferably to satisfy condition (3-3), and even more preferably to satisfy condition (3-4).

[0125] 16≤(Nz×Nf) / Na≤128 (3-1)

[0126] 20≤(Nz×Nf) / Na≤128 (3-2)

[0127] 24≤(Nz×Nf) / Na≤128 (3-3)

[0128] 32≤(Nz×Nf) / Na≤64 (3-4)

[0129] The lens assembly 10 preferably satisfies both conditions (2) and (3). The change in the angle of incidence of light relative to the imaging plane is mainly caused by the changes in the various states of the zoom lens 1, but is significantly affected by the changes in the zoom state, the focus state, and the aperture state in turn. By simultaneously satisfying conditions (2) and (3), the number of focus states and the number of aperture states can be set within an appropriate range, thus suppressing the size of the correction data 22 while effectively correcting color shading.

[0130] By ensuring that the corresponding value of condition (4) is not below the lower limit, it is easy to prevent insufficient correction of color shading. By ensuring that the corresponding value of condition (4) is not above the upper limit, it is possible to suppress the size of the correction data 22 from becoming too large. By satisfying condition (4), it is possible to effectively correct color shading while suppressing the size of the correction data 22.

[0131] To obtain better properties, the lower limit of condition (4) is more preferably set to 320, more preferably 384, and even more preferably 448. To obtain better properties, the upper limit of condition (4) is more preferably set to 1600, more preferably 1296, and even more preferably 1024. For example, it is more preferable to satisfy condition (4) instead of condition (4), more preferably to satisfy condition (4-2), and even more preferably to satisfy condition (4-3).

[0132] 320≤Nz×Nf×Na≤1600 (4-1)

[0133] 384≤Nz×Nf×Na≤1296 (4-2)

[0134] 448≤Nz×Nf×Na≤1024 (4-3)

[0135] Figure 6 Examples of Nz, Nf, and Na in each combination are shown, along with the corresponding values ​​of conditional expressions (2), (3), and (4) calculated from these examples.

[0136] The correction value of the correction data 22 is preferably set to a value at a preset image height. Hereinafter, this preset image height is referred to as the "specific image height". In this invention, the "specific image height" is the image height defined by 0.49×f×tanω, where the focal length and maximum half angle of view of the zoom lens 1 in each zoom state are set to f and ω respectively, and the unit of f is set to mm (millimeters). The specific image height preferably satisfies the following conditional expression (1).

[0137] 1.5mm<0.49×f×tanω<5mm (1)

[0138] By ensuring that the corresponding value of condition (1) is not below the lower limit, it is easy to prevent insufficient correction of color shadows. By ensuring that the corresponding value of condition (1) is not above the upper limit, it is easy to prevent over-correction of color shadows. By satisfying condition (1), it is easy to effectively correct the color shadows in the vertical direction of the image.

[0139] To obtain better properties, the lower limit of condition (1) is more preferably set to 1.7 mm, more preferably 1.9 mm, and even more preferably 2.1 mm. To obtain better properties, the upper limit of condition (1) is more preferably set to 3.5 mm, more preferably 3.2 mm, and even more preferably 3 mm. For example, it is more preferable to satisfy condition (1-1) instead of condition (1), more preferably to satisfy condition (1-2), and even more preferably to satisfy condition (1-3).

[0140] 1.7mm<0.49×f×tanω<3.5mm (1-1)

[0141] 1.9mm<0.49×f×tanω<3.2mm (1-2)

[0142] 2.1mm<0.49×f×tanω<3mm (1-3)

[0143] As a correction value, specifically, it can be set, for example, as the distance on the optical axis between the exit pupil position of a ray incident on a specific image height of the image plane Sim and the image plane Sim. There are many types of rays incident on a specific image height, but among them, the principal ray (i.e., the ray passing through the center of the aperture stop St), the ray passing through the centroid of the spot pattern, or the intermediate ray described below can be used.

[0144] In this specification, for ease of explanation, the ray incident on a specific image height that bisects the angle between the upper and lower rays is referred to as the "intermediate ray". (Reference) Figure 7 and Figure 8 The intermediate light rays are explained.

[0145] exist Figure 7 The text is a jumbled collection of characters and phrases, seemingly from different sources and lacking coherent sentences. A direct translation wouldn Figure 2 The zoom lens 1 shown is in a wide-angle state where it is focused on an object at infinity. The upper ray Ry1 and lower ray Ry2 are incident on a specific image height Ys. The upper ray Ry1 is the ray incident on the specific image height Ys that is furthest from the optical axis Z within a cross-section containing the optical axis Z. The lower ray Ry2 is the ray incident on the specific image height Ys that is closest to the optical axis Z within the same cross-section containing the optical axis Z. The terms "farthest from the optical axis Z" and "closest to the optical axis Z" are determined near the image plane Sim of the zoom lens 1.

[0146] exist Figure 7 In the diagram, the region A near the image plane Sim is represented by a dashed line. Figure 8 The image shows a magnified view of region A. Additionally, in... Figure 7 and Figure 8 In the text, for ease of understanding, the dichroic prism 60 is marked with a slash. Figure 8 The diagram shows an intermediate ray Ry3 incident at an angle that bisects the angle between the upper ray Ry1 and the lower ray Ry2. That is, the angle between the upper ray Ry1 and the intermediate ray Ry3 is equal to the angle between the lower ray Ry2 and the intermediate ray Ry3. As an example, in... Figure 7 The image shows the exit pupil position Pexpw for the intermediate ray Ry3.

[0147] Furthermore, in the technology of this invention, the ray used to set the correction value is not limited to the ray incident on a specific image height. For example, the correction value may also be set as the distance from the image plane (Sim) to the paraxial exit pupil position. Moreover, it is preferable to appropriately determine which value to use as the correction value according to the required specifications, etc. For example, the correction value may be the incident angle of the ray incident on the imaging plane. When the correction value is set as the incident angle of the ray incident on the imaging plane, this ray may be the principal ray of the specific image height, the ray passing through the centroid of the spot pattern of the beam incident on the specific image height, or the aforementioned intermediate ray.

[0148] Furthermore, the correction value is not limited to actual values ​​such as actual distance and actual angle; values ​​obtained by converting actual values ​​can also be used. Examples of conversions include proportional conversion, exponential conversion, number base conversion, 8-bit conversion, and 16-bit conversion.

[0149] [Action Example]

[0150] Next, refer to Figure 9 The flowchart illustrates an example of the operation of this embodiment.

[0151] In step S10, the lens assembly 10 is mounted on the camera device main body 50. The user can change the zoom state, focus state, and / or aperture state of the zoom lens 1 by operating the camera device main body 50 and / or the operation unit (not shown) provided on the lens assembly 10 as needed.

[0152] In step S20, the user uses the zoom lens 1 to photograph the subject. The imaging element 68 captures the image formed by the zoom lens 1 to generate image data, which is then output to the processing unit 70.

[0153] In step S30, each detection unit of the lens assembly 10 detects its respective state during shooting. Specifically, the focus detection unit 12 detects the focus state, the zoom detection unit 14 detects the zoom state, and the aperture detection unit 16 detects the aperture state.

[0154] In step S40, the lens assembly 10 transmits the detected focus state, zoom state, and aperture state to the camera assembly main body 50 via the communication unit 30. Furthermore, the lens assembly 10 retrieves a correction value set for the combination of the detected states from the storage unit 20 and transmits it to the camera assembly main body 50 via the communication unit 30. The processing unit 70 of the camera assembly main body 50 receives the states and correction value via the communication unit 30 and the communication unit 80.

[0155] In step S50, the processing unit 70 performs color and shadow correction on the image data based on the received correction values, generates output image data, and outputs it to the display unit 90. The display unit 90 displays the output image data.

[0156] In step S40 of the above-described operation, the lens device 10 sends a correction value corresponding to the combination of each detected state. However, the present invention is not limited to the above example. For example, the lens device 10 may send all correction values ​​before detecting each state. (See reference...) Figure 10 The flowchart, for Figure 9 Examples of different actions are provided.

[0157] In step S210, the lens assembly 10 is mounted on the camera device main body 50. The user can change the zoom state, focus state, and / or aperture state of the zoom lens 1 by operating the camera device main body 50 and / or the operation unit (not shown) provided with the lens assembly 10 as needed.

[0158] In step S220, the lens assembly 10 sends all color and shadow correction data 22 to the camera assembly main body 50 via the communication unit 30. The processing unit 70 of the camera assembly main body 50 receives the correction data 22 via the communication unit 30 and the communication unit 80.

[0159] In step S230, the user uses the zoom lens 1 to photograph the subject. The imaging element 68 captures the image formed by the zoom lens 1 to generate image data, which is then output to the processing unit 70.

[0160] In step S240, each detection unit of the lens assembly 10 detects a state during shooting. Specifically, the focus detection unit 12 detects the focus state, the zoom detection unit 14 detects the zoom state, and the aperture detection unit 16 detects the aperture state.

[0161] In step S250, the lens assembly 10 transmits the detected focus state, zoom state, and aperture state to the camera assembly main body 50 via the communication unit 30. The processing unit 70 of the camera assembly main body 50 receives the states of the zoom lens 1 via the communication unit 30 and the communication unit 80.

[0162] In step S260, the processing unit 70 reads the correction value set for the combination of the received states from the correction data 22 received in step S220, performs color and shadow correction on the image data based on the read correction value, generates output image data, and outputs it to the display unit 90. The display unit 90 displays the output image data.

[0163] Furthermore, since the values ​​of each state in the correction data are discrete, the detected state values ​​may sometimes differ from those in the correction data. In such cases, the closest value among the values ​​in the correction data can be used, or a correction value can be created through interpolation, and color shading correction can be performed based on this created correction value.

[0164] [Structure of zoom lens]

[0165] Next, the preferred structure and achievable structure of the zoom lens used in the technology of the present invention will be described. In the following description, "specific image height" refers to the image height defined by 0.49×f×tanω as described above. Furthermore, in the following description, to avoid lengthy explanations, the same notation will be used for the same definitions, and repeated explanations of the notation will be omitted.

[0166] In a zoom lens, when focused on an object at infinity, the exit pupil of the principal ray at a specific image height is preferably located further to the image side than the image plane throughout the zoom range. This characteristic is achieved through the lens structure of dynamic image lenses used in imaging optical systems with three-plate dichroic prisms, and it is beneficial for correcting color shading.

[0167] Let Dexp be the distance from the image plane of the zoom lens to the exit pupil of the intermediate light ray, ft be the focal length of the zoom lens at the telephoto end, and fw be the focal length of the zoom lens at the wide-angle end. The zoom lens is preferably configured as follows: Preferably, Dexp is negative at the wide-angle end and positive at the telephoto end, with the focal length of the zoom lens at Dexp being infinity, and the focal length being fw × (ft / fw). 0.6 The above and fw × (ft / fw) 0.9 Within the following range. Furthermore, regarding the sign of Dexp, the distance on the image side is set to positive, and the distance on the object side is set to negative, based on the image plane of the zoom lens. Also, Dexp, ft, and fw are set to values ​​when the zoom lens is focused on an object at infinity. As described above, by setting the value of Dexp to be negative at the wide-angle end, infinity in the intermediate region, and positive at the telephoto end, the absolute value of Dexp can be increased across the entire zoom range. This makes it easier to reduce the angle of incidence of light rays from the zoom lens 1 to the dichroic prism 60, thus improving color shading correction.

[0168] As an example, in Figure 11 The relationship between the focal length and Dexp of the zoom lens in Embodiment 1, described later, is shown. Figure 11 In this example, the horizontal axis is set to focal length, the vertical axis is set to Dexp, and the units of the horizontal and vertical axes are set to mm (millimeters). The data of Example 1 in Table 27, which will be described later, are plotted. Figure 11 Plot point P1 represents the value at the wide-angle end, and plot point P8 represents the value at the telephoto end. Figure 11 In the diagram, dashed lines represent fw × (ft / fw). 0.6 The corresponding focal length and its relationship to fw × (ft / fw) 0.9 The corresponding focal length. Figure 11 The area enclosed by the two dashed lines represents the focal length fw × (ft / fw). 0.6 The above and fw × (ft / fw) 0.9 The following range contains plotted points P6 and P7. The Dexp value of plotted point P6 is negative, and the Dexp value of plotted point P7 is positive. In Embodiment 1 described later, the Dexp value between the focal lengths of plotted points P6 and P7 becomes an infinitely far focal length.

[0169] When the distance from the image plane to the exit pupil of the intermediate ray is set to Dexpw when the zoom lens is focused on an object at infinity at the wide-angle end, the zoom lens preferably satisfies the following condition (8). Furthermore, when an optical component without refractive power is arranged between the image plane Sim and the exit pupil of the intermediate ray, Dexpw is calculated using the air-equivalent distance for that optical component. By ensuring that the corresponding value of condition (8) is not below the lower limit, it is advantageous to reduce the incident angle of the light rays incident on the image plane, thus enabling the optical system to be suitable for a camera optical system with a three-plate dichroic prism. By ensuring that the corresponding value of condition (8) is not above the upper limit, it is easy to shorten the overall length of the optical system, thus facilitating miniaturization.

[0170] 4 < |Dexpw / fw| < 360 (8)

[0171] To obtain better properties, the lower limit of condition (8) is more preferably set to 6, more preferably 8, and more preferably 10. To obtain better properties, the upper limit of condition (8) is more preferably set to 200, more preferably 100, and more preferably 50. For example, it is more preferable to satisfy condition (8) instead of condition (8), more preferably to satisfy condition (8-2), and more preferably to satisfy condition (8-3).

[0172] 6<|Dexpw / fw|<200 (8-1)

[0173] 8<|Dexpw / fw|<100 (8-2)

[0174] 10<|Dexpw / fw|<50 (8-3)

[0175] When the open F-number for focusing on an object at infinity at the telephoto end of a zoom lens is set to FNot, the zoom lens preferably satisfies the following condition (5). By ensuring that the corresponding value of condition (5) is not below the lower limit, it is beneficial to miniaturize the overall optical system, or it is particularly easy to suppress various aberrations at the telephoto end. By ensuring that the corresponding value of condition (5) is not above the upper limit, it is easy to obtain sufficient brightness at the telephoto end, or it is possible to obtain an optical system with high magnification.

[0176] 0.03<FNot / (ft / fw)<0.3 (5)

[0177] To obtain better properties, the lower limit of condition (5) is more preferably set to 0.04, and even more preferably 0.05. To obtain better properties, the upper limit of condition (5) is more preferably set to 0.25, and even more preferably 0.2. For example, it is more preferable to satisfy condition (5) instead of condition (5), and even more preferably to satisfy condition (5-2).

[0178] 0.04<FNot / (ft / fw)<0.25(5-1)

[0179] 0.05<FNot / (ft / fw)<0.2(5-2)

[0180] When the focal length of the lens group with the strongest negative refractive power among the lens groups that move during zoom is set to fn, the zoom lens preferably satisfies the following condition (6). By ensuring that the corresponding value of condition (6) is not below the lower limit, sufficient refractive power for zooming can be ensured, thus facilitating the acquisition of a high-magnification optical system. By ensuring that the corresponding value of condition (6) is not above the upper limit, it is beneficial to suppress various aberrations at the telephoto end.

[0181] -0.4 < fn / ft < -0.02 (6)

[0182] To obtain better characteristics, the lower limit of condition (6) is more preferably set to -0.35, and even more preferably -0.3. To obtain better characteristics, the upper limit of condition (6) is more preferably set to -0.03, and even more preferably -0.04. For example, it is more preferable to satisfy condition (6) instead of condition (6), and even more preferably to satisfy condition (6-2).

[0183] -0.35<fn / ft<-0.03 (6-1)

[0184] -0.3<fn / ft<-0.04 (6-2)

[0185] When the back focal length of the zoom lens, measured in air distance, is set to Bfw, and the maximum half-angle of the zoom lens when focusing on an object at infinity at the wide-angle end is set to ωw, the zoom lens preferably satisfies the following condition (7). By ensuring that the corresponding value of condition (7) is not below the lower limit, the back focal length will not become too short, thus enabling it to be configured as an optical system suitable for a camera optical system with a three-plate dichroic prism. By ensuring that the corresponding value of condition (7) is not above the upper limit, the back focal length will not become too long, thus facilitating miniaturization.

[0186] 4<Bfw / (fw×tanωw)<10 (7)

[0187] To obtain better properties, the lower limit of condition (7) is more preferably set to 4.5, and even more preferably 5. To obtain better properties, the upper limit of condition (7) is more preferably set to 9, and even more preferably 8. For example, it is more preferable to satisfy the following condition (7-1) instead of condition (7), and even more preferably to satisfy the following condition (7-2).

[0188] 4.5<Bfw / (fw×tanωw)<9 (7-1)

[0189] 5<Bfw / (fw×tanωw)<8 (7-2)

[0190] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, one or more but no more than three lens groups that move by changing the spacing between them and adjacent lens groups during zooming, and a final lens group with positive refractive power. This structure is suitable for high-magnification dynamic image lenses used in imaging optical systems with three-plate dichroic prisms, and is beneficial for correcting color shading.

[0191] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second and third lens groups move by changing their spacing. This structure is suitable for use in camera optical systems with three-plate dichroic prisms, providing a lens structure for high-magnification dynamic images with a focal length close to that of a wide-angle lens, and is beneficial for correcting color shading.

[0192] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, and fourth lens groups move by changing the spacing between them and adjacent lens groups. This structure is suitable for high-magnification dynamic image lenses with a focal length close to the standard at the wide-angle end, used in imaging optical systems with three-plate dichroic prisms, and is beneficial for correcting color shading.

[0193] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, and fourth lens groups move by changing the spacing between them and adjacent lens groups. This structure is suitable for use in camera optical systems with dichroic prisms, providing high-magnification dynamic image lenses where the focal length at the wide-angle end ranges from near wide-angle to super-telephoto, and is beneficial for correcting color shading.

[0194] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the spacing between them and adjacent lens groups. This structure is suitable for high-magnification dynamic image lenses with a focal length close to the standard at the wide-angle end, used in imaging optical systems with three-plate dichroic prisms, and is beneficial for correcting color shading.

[0195] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the spacing between them and adjacent lens groups. This structure is suitable for high-magnification dynamic image lenses with a focal length close to the standard at the wide-angle end, used in imaging optical systems with three-plate dichroic prisms, and is beneficial for correcting color shading.

[0196] A zoom lens can be configured such that, from the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second, third, fourth, and fifth lens groups move by changing the spacing between them and adjacent lens groups. This structure is suitable for use in high-magnification (over 40x) dynamic image lenses with a focal length close to the standard at the wide-angle end in camera optical systems with dichroic prisms, and is beneficial for correcting color shading.

[0197] Furthermore, in this specification, a lens group is defined as a group whose spacing in the optical axis direction changes during zooming. During zooming, the spacing between adjacent lenses within a single lens group remains unchanged. That is, a "lens group" is a component of a zoom lens, comprising at least one lens separated by an air gap that changes during zooming. During zooming, each lens group unit can be moved or fixed. A "lens group" may include components other than lenses that do not have refractive power, such as aperture stops.

[0198] The aperture stop can be positioned on the object side of the final lens group, or it can be configured to be included in the movable lens group.

[0199] The first lens group can be configured such that, from the object side to the image side, it consists of a first subgroup A with negative refractive power that is fixed relative to the image plane during focusing, a first subgroup B with positive refractive power that moves along the optical axis Z during focusing, and a first subgroup G1C that moves by changing the interval between itself and the first subgroup B G1B during focusing.

[0200] Structures related to conditional expressions are also included. The preferred structures and achievable structures described above can be combined arbitrarily within the scope of non-contradiction, and preferably selected appropriately according to the required specifications.

[0201] [Second Implementation]

[0202] Figure 12 The diagram shows a functional structure of the imaging device 200 according to the second embodiment of the present invention. The main difference between the second embodiment and the first embodiment is that the zoom lens includes an EX group EX that can be inserted and removed relative to the optical path, and the lens assembly includes an insertion / removal detection unit for detecting the insertion and removal of the EX group EX. In the following description of the second embodiment, the differences from the first embodiment will be explained, and descriptions of identical structures will be omitted.

[0203] The camera device 200 includes a lens device 210 and a camera device body 50. The lens device 210 is detachable from the camera device body 50 and can be mounted on the camera device body 50 via a bayonet 40 provided on the camera device body 50.

[0204] The lens assembly 210 includes a zoom lens 201, a focus detection unit 12, a zoom detection unit 14, an aperture detection unit 16, a plug-in / plug-out detection unit 218, a storage unit 220, and a communication unit 30.

[0205] The zoom lens 201 functions as a camera lens, capturing an image of the subject. Figure 12 The zoom lens 201 is shown conceptually. The zoom lens 201 can, for example, be configured to include the zoom lens 1 of the first embodiment and an EX group EX that can be plugged into or removed from the optical path of the zoom lens 1. By plugging or removing the EX group EX, the focal length of the zoom lens 201 changes.

[0206] EX group EX can be configured, for example, as a teleconverter lens that, when inserted into the optical path, makes the focal length of the lens system after insertion longer than that of the lens system before insertion. Preferably, the imaging position remains constant even when EX group EX is inserted or removed. Regarding the maximum image height, it can be configured to remain constant even when EX group EX is inserted or removed, or it can be configured to change due to the insertion or removal of EX group EX. Furthermore, the term "remain constant" as used herein also includes cases where the error is kept constant within the generally permissible range of the art to which this invention pertains.

[0207] The insertion / removal detection unit 218 detects the insertion / removal status of EX group EX.

[0208] Storage unit 220 stores correction data 222. Correction data 222 is data used to correct color shading in image data obtained by capturing images using the camera body 50. Correction data 222 has correction values ​​set individually for each combination of zoom state, focus state, and aperture state of the zoom lens 1. Furthermore, each insertion / removal state of the EX group EX is also set with a correction value. Depending on the insertion / removal state of the EX group EX, the angle of incidence of light relative to the imaging surface differs. Therefore, each insertion / removal state of the EX group EX has a separate correction value, and the correction value is switched according to the insertion / removal state, thereby enabling more accurate correction.

[0209] A correction value is set for each insertion / removal state of EX group EX. Otherwise, the correction data 222 of the second embodiment can be understood in the same way as the correction data 22 of the first embodiment. That is, the preferred structure and the structure that can be implemented regarding the correction value of the second embodiment can also be understood in the same way as the correction value of the first embodiment.

[0210] In the second embodiment, when the zoom lens states are sent from the lens assembly 210 to the camera assembly 50, the zoom state, focus state, aperture state, and the insertion / removal state of the EX group EX are sent. The processing unit 70 of the camera assembly 50 performs color and shading correction based on correction values ​​set for the combination of the zoom state, focus state, aperture state, and the insertion / removal state of the EX group EX.

[0211] [Example of a zoom lens]

[0212] Next, embodiments of the zoom lens of the present invention will be described with reference to the accompanying drawings. Furthermore, the reference numerals labeled in each group of cross-sectional views of each embodiment are used independently in each embodiment to avoid complicating the description and drawings as the number of reference numerals increases. Therefore, even if common reference numerals are used in the drawings of different embodiments, they do not necessarily represent common structures.

[0213] [Example 1]

[0214] A cross-sectional view of the structure and movement trajectory of the zoom lens of Example 1 are shown below. Figure 13 .exist Figure 13 In the diagram, the upper section labeled "Wide" shows the wide-angle end, and the lower section labeled "Tele" shows the telephoto end. Between the upper and lower sections, solid arrows represent the approximate movement trajectory of each lens group during zoom, from the wide-angle end to the telephoto end. Figure 13 In the image, the on-axis beam at the wide-angle end and the beam at the maximum half-angle angle are shown, as well as the on-axis beam at the telephoto end and the beam at the maximum half-angle angle.

[0215] The zoom lens in Example 1 consists of a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with negative refractive power, and a final lens group GE with positive refractive power, arranged sequentially from the object side to the image side.

[0216] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, arranged sequentially from the object side to the image side. The focusing group consists of subgroup 1B G1B. When focusing from an object at infinity to a closer object, subgroup 1B G1B moves towards the image side, while the other groups remain fixed relative to the image plane Sim. Figure 13 The parentheses and horizontal arrows in subgroup G1B (1B) indicate that subgroup G1B is the focus group and the direction of movement when focusing from an object at infinity to a closer object. This method of illustrating the focus group is the same in the figures of other embodiments.

[0217] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0218] Regarding the zoom lens of Embodiment 1, the basic lens data is shown in Tables 1A and 1B, the specifications and variable surface spacing are shown in Table 2, and the aspherical coefficients are shown in Table 3. In this specification, to avoid making one table too long, the basic lens data is shown in two tables.

[0219] The basic lens data is shown in the table below. The "Sn" column shows the surface numbering with the object-side surface designated as surface 1 and the numbering increasing sequentially towards the image side. The "R" column shows the radius of curvature of each surface. The "D" column shows the surface spacing along the optical axis of each surface and its image-side neighbor. The "Nd" column shows the refractive index of each component relative to the d-line. The "νd" column shows the Abbe number of each component based on the d-line. The "θg,F" column shows the partial dispersion ratio between the g-line and F-line of each component. The "ED" column shows the maximum effective diameter of each surface.

[0220] Furthermore, when the refractive indices of a lens relative to the g-line, F-line, and C-line are set to Ng, NF, and NC respectively, and the partial dispersion ratio between the g-line and F-line of the lens is set to θg,F, θg,F is defined by the following formula.

[0221] θg,F=(Ng-NF) / (NF-NC)

[0222] In the table of basic lens data, the sign of the radius of curvature of the surface that makes the convex shape face the object side is set to positive, and the sign of the radius of curvature of the surface that makes the convex shape face the image side is set to negative. The table of basic lens data also shows the aperture stop St and the dichroic prism 60. The surface number and the statement (St) are recorded in the surface number column corresponding to the aperture stop St. The value in the bottom column of column D of Table 1B is the interval between the surface closest to the image side and the image plane Sim. Regarding the variable surface interval during zoom, the notation DD[ ] is used, and the object side surface number of the interval is marked in [ ] and recorded in the surface interval column.

[0223] Table 2 shows the zoom ratio Zr, focal length f, open F-number FNo., maximum field of view 2ω, and variable surface spacing, using the d-line as a reference. The zoom ratio has the same meaning as the zoom factor and zoom magnification. The [°] in the 2ω column indicates the unit as degrees. In Table 2, the values ​​for the wide-angle, middle focal length, and telephoto ends are shown in the columns labeled "Wide," "Middle," and "Tele," respectively.

[0224] In the table of basic lens data, the aspherical surface number is marked with an asterisk (*), and the paraxial radius of curvature value is recorded in the aspherical surface radius of curvature column. In Table 3, the aspherical surface number is shown in row Sn, and the aspherical coefficient values ​​for each aspherical surface are shown in rows KA and Am. Furthermore, m in Am is an integer greater than or equal to 3, and varies depending on the surface. For example, on the first surface of Example 1, m = 4, 6, 8, ... 20. The aspherical coefficient values ​​in Table 3, “E±n” (n: integer), represent “×10”. ±n KA and Am are the aspheric coefficients in the aspheric formula expressed by the following equation.

[0225] Zd=C×h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+ΣAm×h m

[0226] in,

[0227] Zd: Aspherical depth (the length of the perpendicular line from a point on the aspherical surface at height h to the plane perpendicular to the optical axis Z that is in contact with the vertex of the aspherical surface)

[0228] h: Height (distance from the optical axis Z to the lens surface)

[0229] C: The reciprocal of the paraxial radius of curvature

[0230] KA, Am: These are aspherical coefficients. In the aspherical form, Σ refers to the summation related to m.

[0231] In the data in each table, degrees are used as the unit of angle, and millimeters (mm) are used as the unit of length. The optical system can use both magnification and reduction scales, so other appropriate units can also be used. Furthermore, the tables shown below record the pre-set rounded values ​​to a predetermined number of digits.

[0232]

[0233]

[0234]

[0235]

[0236] exist Figure 14 The diagram shows the aberrations of the zoom lens of Embodiment 1 when it is focused on an object at infinity. Figure 14In the diagram, the upper section marked "Wide" shows aberrations at the wide-angle end, the middle section marked "Middle" shows aberrations at the intermediate focal length, and the lower section marked "Tele" shows aberrations at the telephoto end. Figure 14 In the diagram, from left to right, spherical aberration, astigmatism, distortion aberration, and chromatic aberration are shown. In the spherical aberration diagram, aberrations along the d-line, C-line, F-line, and g-line are shown using solid lines, long dashed lines, short dashed lines, and single-dot dashed lines, respectively. In the astigmatism diagram, aberrations along the d-line in the sagittal direction are shown using solid lines, and aberrations along the d-line in the meridional direction are shown using short dashed lines. In the distortion aberration diagram, aberrations along the d-line are shown using solid lines. In the chromatic aberration diagram, aberrations along the C-line, F-line, and g-line are shown using long dashed lines, short dashed lines, and single-dot dashed lines, respectively. In the spherical aberration diagram, the open F-value is shown after "FNo.=". In the other aberration diagrams, the maximum half-angle value is shown after "ω=".

[0237] The notations, meanings, recording methods, and illustration methods of the data related to Embodiment 1 above are basically the same in the following embodiments unless otherwise specified, so repeated descriptions are omitted below.

[0238] [Example 2]

[0239] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 2 are shown below. Figure 15 The zoom lens in Example 2 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with negative refractive power, a fifth lens group G5 with negative refractive power, and a final lens group GE with positive refractive power.

[0240] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, sequentially from the object side to the image side. The zoom lens of Embodiment 2 has two focusing groups: subgroup 1B G1B and subgroup 1C G1C. When focusing from an object at infinity to a closer object, subgroups 1B G1B and 1C G1C change their spacing and move towards the object side, while the other groups remain fixed relative to the image plane (Sim).

[0241] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0242] Regarding the zoom lens of Example 2, basic lens data are shown in Tables 4A and 4B, specifications and variable plane spacing are shown in Table 5, and various aberrations are illustrated in Table 5. Figure 16 .

[0243]

[0244]

[0245]

[0246] [Example 3]

[0247] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 3 are shown below. Figure 17 The zoom lens in Example 3 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a final lens group GE with positive refractive power.

[0248] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, sequentially from the object side to the image side. The zoom lens in Embodiment 3 has two focusing groups: subgroup 1B G1B and subgroup 1C G1C. When focusing from an object at infinity to a closer object, subgroups 1B G1B and 1C G1C change their spacing and move towards the object side, while the other groups remain fixed relative to the image plane Sim.

[0249] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0250] Regarding the zoom lens of Example 3, basic lens data are shown in Tables 6A and 6B, specifications and variable surface spacing are shown in Table 7, aspherical coefficients are shown in Table 8, and various aberrations are illustrated in Table 6B. Figure 18 .

[0251]

[0252]

[0253]

[0254]

[0255] [Example 4]

[0256] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 4 are shown below. Figure 19The zoom lens in Example 4 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with negative refractive power, a fifth lens group G5 with positive refractive power, and a final lens group GE with positive refractive power.

[0257] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, sequentially from the object side to the image side. The zoom lens of Embodiment 4 has two focusing groups: subgroup 1B G1B and subgroup 1C G1C. When focusing from an object at infinity to a closer object, subgroups 1B G1B and 1C G1C change their spacing and move towards the object side, while the other groups remain fixed relative to the image plane Sim.

[0258] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0259] Regarding the zoom lens of Example 4, basic lens data are shown in Tables 9A and 9B, specifications and variable surface spacing are shown in Table 10, aspherical coefficients are shown in Table 11, and various aberrations are illustrated in Table 9B. Figure 20 .

[0260]

[0261]

[0262]

[0263]

[0264] [Example 5]

[0265] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 5 are shown below. Figure 21 The zoom lens in Example 5 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, and a final lens group GE with positive refractive power.

[0266] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, sequentially from the object side to the image side. The zoom lens of Embodiment 5 has two focusing groups: subgroup 1B G1B and subgroup 1C G1C. When focusing from an object at infinity to a closer object, subgroups 1B G1B and 1C G1C change their spacing and move towards the object side, while the other groups remain fixed relative to the image plane Sim.

[0267] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0268] Regarding the zoom lens of Example 5, basic lens data are shown in Tables 12A and 12B, specifications and variable surface spacing are shown in Table 13, aspherical coefficients are shown in Table 14, and various aberrations are illustrated in Table 15. Figure 22 .

[0269]

[0270]

[0271]

[0272]

[0273] [Example 6]

[0274] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 6 are shown below. Figure 23 The zoom lens of Embodiment 6 has a structure that adds an EX group EX to the zoom lens of Embodiment 5. In the zoom lens of Embodiment 6, the EX group EX can be plugged in and out relative to the optical path. Figure 23 The diagram shows the state where the EX group EX is inserted in the optical path between the fourth lens group G4 and the final lens group GE. The structure of the lens groups other than the EX group EX, the movement of each lens group during focusing, and the movement of each lens group during zooming are the same as the operation of the zoom lens in Embodiment 5.

[0275] Regarding the zoom lens of Example 6, basic lens data are shown in Tables 15A and 15B, specifications and variable surface spacing are shown in Table 16, aspherical coefficients are shown in Table 17, and various aberrations are illustrated in Table 15B. Figure 24 .

[0276]

[0277]

[0278]

[0279]

[0280] [Example 7]

[0281] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 7 are shown below. Figure 25The zoom lens in Example 7 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with negative refractive power, and a final lens group GE with positive refractive power.

[0282] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, arranged sequentially from the object side to the image side. The focusing group consists of subgroup 1B G1B. When focusing from an object at infinity to a closer object, subgroup 1B G1B moves towards the image side, while the other groups remain fixed relative to the image plane Sim.

[0283] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0284] Regarding the zoom lens of Example 7, basic lens data are shown in Tables 18A and 18B, specifications and variable surface spacing are shown in Table 19, aspherical coefficients are shown in Table 20, and various aberrations are illustrated in Table 18B. Figure 26 .

[0285]

[0286]

[0287]

[0288]

[0289] [Example 8]

[0290] A cross-sectional view of the structure and movement trajectory of the zoom lens in Example 8 are shown. Figure 27 The zoom lens in Example 8 consists of, from the object side to the image side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a final lens group GE with positive refractive power.

[0291] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, sequentially from the object side to the image side. The zoom lens of Embodiment 8 has two focusing groups: subgroup 1B G1B and subgroup 1C G1C. When focusing from an object at infinity to a closer object, subgroups 1B G1B and 1C G1C change their spacing and move towards the object side, while the other groups remain fixed relative to the image plane Sim.

[0292] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0293] Regarding the zoom lens of Example 8, basic lens data are shown in Tables 21A and 21B, specifications and variable surface spacing are shown in Table 22, aspherical coefficients are shown in Table 23, and various aberrations are illustrated in Table 24. Figure 28 .

[0294]

[0295]

[0296]

[0297]

[0298] [Example 9]

[0299] A cross-sectional view of the structure and movement trajectory of the zoom lens of Example 9 are shown below. Figure 29 The zoom lens in Example 9 consists of a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with negative refractive power, and a final lens group GE with positive refractive power, arranged sequentially from the object side to the image side.

[0300] The first lens group G1 consists of subgroup 1A G1A, subgroup 1B G1B, and subgroup 1C G1C, arranged sequentially from the object side to the image side. The focusing group consists of subgroup 1B G1B. When focusing from an object at infinity to a closer object, subgroup 1B G1B moves towards the image side, while the other groups remain fixed relative to the image plane Sim.

[0301] When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed relative to the image plane Sim, while the other lens groups change the spacing between themselves and the adjacent lens groups and move along the optical axis Z.

[0302] Regarding the zoom lens of Example 9, basic lens data are shown in Tables 24A and 24B, specifications and variable plane spacing are shown in Table 25, and various aberrations are illustrated in... Figure 30 .

[0303]

[0304]

[0305]

[0306] Table 26 shows the corresponding values ​​of conditional equation (1) and conditions (5) to (8) for the zoom lenses of Examples 1 to 9. Examples of the corresponding values ​​of conditions (2) to (4) are shown below. Figure 6 As shown. The unit of the corresponding value in conditional expression (1) of Table 26 is mm (millimeters). Table 26 and... Figure 6 The values ​​shown are used as upper or lower limits of the condition to set the preferred range of the condition.

[0307]

[0308] The Dexp values ​​for each focal length of the zoom lenses in Examples 1 to 9 are shown in Tables 27 to 29. The values ​​shown in Tables 27 to 29 are the values ​​when the zoom lens is focused on an object at infinity.

[0309]

[0310]

[0311]

[0312] [Variation Example]

[0313] The above description, through examples and embodiments, illustrates the technology of the present invention. However, the technology of the present invention is not limited to the above examples and embodiments, and various modifications are possible. For example, the radius of curvature, interplanar spacing, refractive index, Abbe number, and aspherical coefficient of each lens included in the zoom lens are not limited to the values ​​shown in the above embodiments, and other values ​​can be used.

[0314] The zoom lens can be configured to include an image stabilization group, which consists of at least one lens that moves during image shake correction. The lens assembly can be configured to include an image shake detection unit that detects the position of the image stabilization group and uses the detected position to detect the state of image shake correction. In this case, the correction data used to correct color shading preferably has a correction value set for each state of image shake correction.

[0315] In the above example, a three-plate dichroic prism that separates a light beam into three colors—blue, red, and green—was described as a dichroic prism. However, the dichroic prism of the present invention is not limited to the above example. In the technology of the present invention, the colors of the separated light beams, the order in which the colored light beams are separated, and the number of separated light beams may differ from the above example.

[0316] In the above description, an example of a camera device body including a processing unit for color and shadow correction was given. However, in the technology of the present invention, a lens device may be configured to include a processing unit for color and shadow correction.

[0317] The camera device of the present invention is not limited to a broadcast camera, and can be configured as a movie camera, digital camera, video camera, surveillance camera, FA (Factory Automation) camera, MV (Machine Vision) camera, etc.

[0318] The following notes further disclose the above-described implementation methods and embodiments.

[0319] [Postscript 1]

[0320] A lens device comprising a zoom lens, wherein...

[0321] The zoom lens includes: a first lens group, comprising a focusing group that moves during focusing and is positioned closest to the object, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the spacing between themselves and adjacent lens groups during zooming; and a final lens group positioned closest to the image plane and fixed relative to the image plane during zooming.

[0322] The lens assembly can be attached to and detached from the main body of the camera device, which has a dichroic prism.

[0323] The lens device includes:

[0324] The storage unit stores correction data for correcting color shading in image data obtained by capturing an image formed by the zoom lens through the dichroic prism using the main body of the imaging device; and

[0325] The communication unit sends the correction data to the main body of the camera device.

[0326] The correction data includes correction values ​​set at a specific image height for various combinations of zoom state, focus state, and aperture state of the zoom lens.

[0327] With the focal length and maximum half angle of view of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the specific image height is defined as 0.49 × f × tanω.

[0328] The lens assembly satisfies the following condition (1):

[0329] 1.5mm<0.49×f×tanω<5mm (1).

[0330] [Postscript 2]

[0331] A lens device comprising a zoom lens, wherein...

[0332] The zoom lens includes: a first lens group, comprising a focusing group that moves during focusing and is positioned closest to the object, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the spacing between themselves and adjacent lens groups during zooming; and a final lens group positioned closest to the image plane and fixed relative to the image plane during zooming.

[0333] The lens assembly can be attached to and detached from the main body of the camera device, which has a dichroic prism.

[0334] The lens device includes:

[0335] The storage unit stores correction data for correcting color shading in image data obtained by capturing an image formed by the zoom lens through the dichroic prism using the main body of the imaging device; and

[0336] The communication unit sends the correction data to the main body of the camera device.

[0337] The correction data includes correction values ​​set for various combinations of zoom state, focus state, and aperture state of the zoom lens.

[0338] When the number of zoom states, the number of focus states, and the number of aperture states in each group are set to Nz, Nf, and Na, respectively.

[0339] The lens assembly satisfies the following conditions (2) and (3):

[0340] 0.05≤Nf / (Nz×Na)≤0.3 (2)

[0341] 8≤(Nz×Nf) / Na≤256 (3).

[0342] [Postscript 3]

[0343] According to the lens assembly described in Appendix 2, wherein...

[0344] With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω.

[0345] The lens assembly satisfies the following condition (1):

[0346] 1.5mm<0.49×f×tanω<5mm (1).

[0347] [Postscript 4]

[0348] The lens device according to any one of Appendices 1 to 3, wherein...

[0349] When the number of zoom states, the number of focus states, and the number of aperture states in each group are set to Nz, Nf, and Na, respectively.

[0350] The lens assembly satisfies the following conditional expression (4):

[0351] 256≤Nz×Nf×Na≤2048 (4).

[0352] [Postscript 5]

[0353] The lens device according to any one of Appendices 1 to 4, wherein...

[0354] With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω.

[0355] The ray incident at a specific image height on the image plane of the zoom lens, whose angle is bisected by the angle formed by the upper ray and the lower ray, is defined as the intermediate ray.

[0356] The focal length of the zoom lens when focusing on an object at infinity at the telephoto end is set to ft.

[0357] The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw.

[0358] Let Dexp be the distance from the image plane of the zoom lens when it is focused on an object at infinity to the position of the exit pupil of the intermediate ray.

[0359] The Dexp symbol is based on the image plane, with the image-side distance set to positive and the object-side distance set to negative.

[0360] The zoom lens has a negative Dexp at the wide-angle end.

[0361] The zoom lens has a positive Dexp at the telephoto end.

[0362] The focal length of the zoom lens, where Dexp is at infinity, is fw × (ft / fw). 0.6 The above and fw × (ft / fw) 0.9 Within the following range.

[0363] [Postscript 6]

[0364] The lens device according to any one of Appendices 1 to 5, wherein...

[0365] The zoom lens, from the object side to the image side, consists of, in sequence, a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, one or more but no more than three lens groups that move by changing the interval between them and adjacent lens groups during zooming, and a final lens group with positive refractive power.

[0366] [Postscript 7]

[0367] The lens device according to any one of Appendices 1 to 5, wherein...

[0368] The zoom lens consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, and a final lens group with positive refractive power, arranged sequentially from the object side to the image side. During zooming, the second lens group and the third lens group move by changing their relative spacing.

[0369] [Postscript 8]

[0370] The lens device according to any one of Appendices 1 to 5, wherein...

[0371] The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power.

[0372] During zooming, the second lens group, the third lens group, and the fourth lens group move by changing the interval between them and the adjacent lens groups.

[0373] [Postscript 9]

[0374] The lens device according to any one of Appendices 1 to 5, wherein...

[0375] The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power.

[0376] During zooming, the second lens group, the third lens group, and the fourth lens group move by changing the interval between them and the adjacent lens groups.

[0377] [Postscript 10]

[0378] The lens device according to any one of Appendices 1 to 5, wherein...

[0379] The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power.

[0380] During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

[0381] [Postscript 11]

[0382] The lens device according to any one of Appendices 1 to 5, wherein...

[0383] The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, and a final lens group with positive refractive power.

[0384] During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

[0385] [Postscript 12]

[0386] The lens device according to any one of Appendices 1 to 5, wherein...

[0387] The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power.

[0388] During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

[0389] [Postscript 13]

[0390] The lens device according to any one of Appendices 1 to 12 comprises:

[0391] The EX group is capable of being plugged in and out relative to the optical path of the zoom lens, and the focal length can be changed by such plugging and unplugging; and

[0392] The insertion / removal detection unit detects the insertion / removal status.

[0393] The correction value is set for each of the insertion / removal states.

[0394] [Postscript 14]

[0395] The lens device according to any one of Appendices 1 to 13, wherein,

[0396] When the zoom lens is focused on an object at infinity at its telephoto end, the open F-value is set to FNot.

[0397] The focal length of the zoom lens when focusing on an object at infinity at the telephoto end is set to ft.

[0398] When the focal length of the zoom lens is set to fw at the wide-angle end and focused on an object at infinity,

[0399] The lens assembly satisfies the following condition (5):

[0400] 0.03<FNot / (ft / fw)<0.3 (5).

[0401] [Postscript 15]

[0402] The lens device according to any one of Appendices 1 to 14, wherein,

[0403] The focal length of the lens group with the strongest negative refractive power among the lens groups included in the zoom lens that move during zooming is set as fn.

[0404] When the focal length of the zoom lens is set to ft when focusing on an object at infinity at the telephoto end,

[0405] The lens assembly satisfies the following condition (6):

[0406] -0.4<fn / ft<-0.02 (6).

[0407] [Postscript 16]

[0408] The lens assembly according to any one of Appendices 1 to 15, wherein,

[0409] The first lens group of the zoom lens consists of, from the object side to the image side, a first A subgroup with negative refractive power that is fixed relative to the image plane during focusing, a first B subgroup with positive refractive power that moves along the optical axis during focusing, and a first C subgroup whose interval with the first B subgroup changes during focusing.

[0410] [Postscript 17]

[0411] The lens device according to any one of Appendices 1 to 16, wherein,

[0412] The back focal length of the zoom lens, measured in air distance, is set to Bfw.

[0413] The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw.

[0414] When the maximum half-angle view of the zoom lens focused on an object at infinity at the wide-angle end is set to ωw,

[0415] The lens assembly satisfies the following conditional expression (7):

[0416] 4<Bfw / (fw×tanωw)<10 (7).

[0417] [Postscript 18]

[0418] The lens assembly according to any one of Appendices 1 to 17, wherein,

[0419] With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω.

[0420] The ray incident at a specific image height on the image plane of the zoom lens, whose angle is bisected by the angle formed by the upper ray and the lower ray, is defined as the intermediate ray.

[0421] The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw.

[0422] Let Dexpw be the distance from the image plane to the exit pupil of the intermediate ray when the zoom lens is focused on an object at infinity at its wide-angle end.

[0423] When an optical component without refractive power is disposed between the image plane and the exit pupil position of the intermediate ray, and Dexpw is calculated using the air-equivalent distance for the optical component,...

[0424] The lens assembly satisfies the following condition (8):

[0425] 4<|Dexpw / fw|<360 (8).

[0426] [Postscript 19]

[0427] The lens assembly according to any one of Appendices 1 to 18, wherein,

[0428] With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω.

[0429] When the zoom lens is focused on an object at infinity, the exit pupil position of the principal ray of the specific image height is located further to the image side than the image plane throughout the entire zoom area.

[0430] [Postscript 20]

[0431] A camera device comprising:

[0432] The lens device described in any one of Appendices 1 to 19; and

[0433] The main body of the camera device,

[0434] The main body of the camera device includes:

[0435] The dichroic prism;

[0436] Imaging element, capturing the image formed by the zoom lens; and

[0437] The processing unit performs color and shadow correction processing on the image data based on the correction data sent from the lens device.

Claims

1. A lens device comprising a zoom lens, wherein, The zoom lens includes: a first lens group, comprising a focusing group that moves during focusing and is positioned closest to the object, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the spacing between themselves and adjacent lens groups during zooming; and a final lens group positioned closest to the image plane and fixed relative to the image plane during zooming. The lens assembly can be attached to and detached from the main body of the camera device, which has a dichroic prism. The lens device includes: The storage unit stores correction data for correcting color shading in image data obtained by capturing an image formed by the zoom lens through the dichroic prism using the main body of the imaging device; and The communication unit sends the correction data to the main body of the camera device. The correction data includes correction values ​​set at a specific image height for various combinations of zoom state, focus state, and aperture state of the zoom lens. With the focal length and maximum half angle of view of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the specific image height is defined as 0.49 × f × tanω. The lens assembly satisfies the following condition (1): 1.5mm<0.49×f×tanω<5mm (1).

2. A lens device comprising a zoom lens, wherein, The zoom lens includes: a first lens group, comprising a focusing group that moves during focusing and is positioned closest to the object, and is fixed relative to the image plane during zooming; a plurality of movable lens groups that move by changing the spacing between themselves and adjacent lens groups during zooming; and a final lens group positioned closest to the image plane and fixed relative to the image plane during zooming. The lens assembly can be attached to and detached from the main body of the camera device, which has a dichroic prism. The lens device includes: The storage unit stores correction data for correcting color shading in image data obtained by capturing an image formed by the zoom lens through the dichroic prism using the main body of the imaging device; and The communication unit sends the correction data to the main body of the camera device. The correction data includes correction values ​​set for various combinations of zoom state, focus state, and aperture state of the zoom lens. When the number of zoom states, the number of focus states, and the number of aperture states in each group are set to Nz, Nf, and Na, respectively. The lens assembly satisfies the following conditions (2) and (3): 0.05≤Nf / (Nz×Na)≤0.3 (2) 8≤(Nz×Nf) / Na≤256 (3).

3. The lens device according to claim 2, wherein, With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω. The lens assembly satisfies the following condition (1): 1.5mm<0.49×f×tanω<5mm (1).

4. The lens device according to claim 1 or 2, wherein, When the number of zoom states, the number of focus states, and the number of aperture states in each group are set to Nz, Nf, and Na, respectively. The lens assembly satisfies the following conditional expression (4): 256≤Nz×Nf×Na≤2048 (4).

5. The lens device according to claim 1 or 2, wherein, With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω. The ray incident at a specific image height on the image plane of the zoom lens, whose angle is bisected by the angle formed by the upper ray and the lower ray, is defined as the intermediate ray. The focal length of the zoom lens when focusing on an object at infinity at the telephoto end is set to ft. The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw. Let Dexp be the distance from the image plane of the zoom lens when it is focused on an object at infinity to the position of the exit pupil of the intermediate ray. The Dexp symbol is based on the image plane, with the image-side distance set to positive and the object-side distance set to negative. The zoom lens has a negative Dexp at the wide-angle end. The zoom lens has a positive Dexp at the telephoto end. The focal length of the zoom lens, where Dexp becomes infinity, is fw × (ft / fw). 0.6 The above and fw × (ft / fw) 0.9 Within the following range.

6. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of, in sequence, a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, one or more but no more than three lens groups that move by changing the interval between them and adjacent lens groups during zooming, and a final lens group with positive refractive power.

7. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second lens group and the third lens group move by changing their relative spacing.

8. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second lens group, the third lens group, and the fourth lens group move by changing the interval between them and the adjacent lens groups.

9. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second lens group, the third lens group, and the fourth lens group move by changing the interval between them and the adjacent lens groups.

10. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

11. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, and a final lens group with positive refractive power. During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

12. The lens device according to claim 1 or 2, wherein, The zoom lens, from the object side to the image side, consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a final lens group with positive refractive power. During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move by changing the interval between them and the adjacent lens groups.

13. The lens device according to claim 1 or 2, comprising: The EX group is capable of being plugged in and out relative to the optical path of the zoom lens, and the focal length can be changed by such plugging and unplugging; and The insertion / removal detection unit detects the insertion / removal status. The correction value is set for each of the insertion / removal states.

14. The lens device according to claim 6, wherein, When the zoom lens is focused on an object at infinity at its telephoto end, the open F-value is set to FNot. The focal length of the zoom lens when focusing on an object at infinity at the telephoto end is set to ft. When the focal length of the zoom lens is set to fw at the wide-angle end and focused on an object at infinity, The lens assembly satisfies the following condition (5): 0.03<FNot / (ft / fw)<0.3 (5).

15. The lens device according to claim 6, wherein, The focal length of the lens group with the strongest negative refractive power among the lens groups included in the zoom lens that move during zooming is set as fn. When the focal length of the zoom lens is set to ft when focusing on an object at infinity at the telephoto end, The lens assembly satisfies the following condition (6): -0.4<fn / ft<-0.02 (6).

16. The lens device according to claim 6, wherein, The first lens group of the zoom lens consists of, from the object side to the image side, a first A subgroup with negative refractive power that is fixed relative to the image plane during focusing, a first B subgroup with positive refractive power that moves along the optical axis during focusing, and a first C subgroup whose interval with the first B subgroup changes during focusing.

17. The lens device according to claim 1 or 2, wherein, The back focal length of the zoom lens, measured in air distance, is set to Bfw. The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw. When the maximum half-angle view of the zoom lens focused on an object at infinity at the wide-angle end is set to ωw, The lens assembly satisfies the following conditional expression (7): 4<Bfw / (fw×tanωw)<10 (7).

18. The lens device according to claim 1 or 2, wherein, With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω. The ray incident at a specific image height on the image plane of the zoom lens, whose angle is bisected by the angle formed by the upper ray and the lower ray, is defined as the intermediate ray. The focal length of the zoom lens in the state of focusing on an object at infinity at the wide-angle end is set to fw. Let Dexpw be the distance from the image plane to the exit pupil of the intermediate ray when the zoom lens is focused on an object at infinity at its wide-angle end. When an optical component without refractive power is disposed between the image plane and the exit pupil position of the intermediate ray, and Dexpw is calculated using the air-equivalent distance for the optical component,... The lens assembly satisfies the following condition (8): 4<|Dexpw / fw|<360 (8).

19. The lens device according to claim 1 or 2, wherein, With the focal length and maximum half-angle of the zoom lens in each zoom state set to f and ω respectively, and the unit of f set to mm, the correction value is a value at a specific image height defined by 0.49 × f × tanω. When the zoom lens is focused on an object at infinity, the exit pupil position of the principal ray of the specific image height is located further to the image side than the image plane throughout the entire zoom area.

20. A camera device comprising: The lens device according to any one of claims 1 to 19; and The main body of the camera device, The main body of the camera device includes: The dichroic prism; An imaging element that captures the image formed by the zoom lens; and The processing unit performs color and shadow correction processing on the image data based on the correction data sent from the lens device.

Images