Lens device and imaging device

Abstract

The present invention provides a lens device advantageous for correcting color shading, and an imaging device equipped with this lens device. [Solution] The lens device is detachable from the main body of an imaging device having a color separation prism, and includes a storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens with the main body of the imaging device via the color separation prism, and a communication unit that transmits the correction data to the main body of the imaging device. The correction data has correction values ​​set for each combination of the zoom state, focus state and aperture state of the zoom lens. The zoom lens includes a first lens group that is positioned closest to the object and is fixed during magnification, including a focus group, a plurality of movable lens groups that move during magnification, and a final lens group that is positioned closest to the image and is fixed during magnification.

Description

[Technical Field]

[0001] The technology disclosed herein relates to a lens device and an imaging device. [Background technology]

[0002] Conventionally, the imaging device described in Patent Document 1 below is known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-210371 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventionally, color-separating prisms that separate a light beam into its three primary colors, such as a three-plate color-separating prism that separates it into the three primary colors of blue, green, and red, are known. In imaging devices, when the imaging light beam is separated into its three primary colors using such a three-plate color-separating prism, a phenomenon called color shading may occur, in which the color tone differs in the vertical direction of the image.

[0005] This disclosure provides a lens device advantageous for correcting color shading, and an imaging device equipped with this lens device. [Means for solving the problem]

[0006] A lens device according to a first aspect of this disclosure is a lens device comprising a zoom lens, the zoom lens comprising a first lens group that includes a focus group that moves when focusing and is positioned closest to the object and fixed to the image plane when zooming, a plurality of moving lens groups that move by changing the distance between adjacent lens groups when zooming, and a final lens group that is positioned closest to the image and fixed to the image plane when zooming, the lens device is detachable from an imaging device body having a color separation prism, and comprises a storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens with the imaging device body via the color separation prism, and a communication unit that transmits the correction data to the imaging device body, the correction data having correction values ​​set for each combination of the zoom state, focus state and aperture state of the zoom lens at a specific image height, where the focal length and maximum half-angle of view of the zoom lens in each zoom state are f and ω, respectively, and the unit of f is mm, the specific image height is defined as 0.49 × f × tanω, 1.5 mm < 0.49 × f × tanω < 5 mm (1) The condition (1) expressed by is satisfied.

[0007] A lens device according to a second aspect of the present disclosure is a lens device comprising a zoom lens, the zoom lens comprising a first lens group that is positioned closest to the object and fixed to the image plane during magnification, including a focus group that moves when focusing, a plurality of moving lens groups that move by changing the distance between adjacent lens groups during magnification, and a final lens group that is positioned closest to the image and fixed to the image plane during magnification, the lens device is detachable from an imaging device body having a color separation prism, and comprises a storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens with the imaging device body via the color separation prism, and a communication unit that transmits the correction data to the imaging device body, the correction data having correction values ​​set for each combination of the zoom state, focus state and aperture state of the zoom lens, and when the number of zoom states, the number of focus states and the number of aperture states in each combination group are Nz, Nf, and Na, respectively, 0.05 ≤ Nf / (Nz × Na) ≤ 0.3 (2) 8 ≤ (Nz × Nf) / Na ≤ 256 (3) This lens device satisfies the conditions (2) and (3) expressed by .

[0008] In the lens device of the second embodiment, the focal length and maximum half-angle of view of the zoom lens in each zoom state are f and ω, respectively, and the unit of f is mm, the correction value is the value at a specific image height defined as 0.49 × f × tanω, and the lens device is 1.5 mm < 0.49 × f × tanω < 5 mm (1) It is preferable that the condition (1) expressed by is satisfied.

[0009] In the lens device of the above embodiment, if the number of zoom states, the number of focus states, and the number of aperture states in each combination group are Nz, Nf, and Na, 256 ≤ Nz × Nf × Na ≤ 2048 (4) It is preferable that the condition (4) expressed by is satisfied.

[0010] Let f and ω be the focal length and maximum half-angle of view of the zoom lens at each zoom state, respectively, with the unit of f being mm. The correction value is the value at a specific image height defined as 0.49 × f × tanω. Among the rays incident on the image plane of the zoom lens at a specific image height, the ray that incident at an angle bisector of the angle between the upper and lower rays is defined as the intermediate ray. Let ft be the focal length when the zoom lens is focused on an object at infinity at its telephoto end, and fw be the focal length when the zoom lens is focused on an object at infinity at its wide-angle end. Let Dexp be the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an object at infinity. The sign of Dexp is such that, with the image plane as the reference, the distance on the image side is positive and the distance on the object side is negative. Therefore, Dexp at the wide-angle end of the zoom lens is negative, and Dexp at the telephoto end of the zoom lens is positive. The focal length of the zoom lens when Dexp is at infinity is fw × (ft / fw). 0.6 The above and fw×(ft / fw) 0.9 It is preferable that the range be as follows:

[0011] A zoom lens may be configured to consist of, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power that moves when the zoom is changed, one or more but no more than three lens groups that move by changing the distance between adjacent lens groups when the zoom is changed, and a final lens group having positive refractive power.

[0012] 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 in order from the object side to the image side. When the magnification is changed, the second and third lens groups may be configured to move while changing their relative distance from each other.

[0013] The zoom lens consists of, in order from the object side to the image side, 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. When the magnification is changed, the second, third, and fourth lens groups may be configured to move by changing the distance between them and adjacent lens groups.

[0014] The zoom lens consists of, in order from the object side to the image side, 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. When the magnification is changed, the second, third, and fourth lens groups may be configured to move by changing the distance between them and adjacent lens groups.

[0015] The zoom lens consists of, in order from the object side to the image side, 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. When the zoom is changed, the second, third, fourth, and fifth lens groups may be configured to move by changing the distance between them and adjacent lens groups.

[0016] The zoom lens consists of, in order from the object side to the image side: a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, and a final lens group having positive refractive power. During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group may be configured to move while changing the spacing between adjacent lens groups.

[0017] The zoom lens consists of, in order from the object side to the image side: a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having negative refractive power, and a final lens group having positive refractive power. During zooming, the second lens group, the third lens group, the fourth lens group, and the fifth lens group may be configured to move while changing the spacing between adjacent lens groups.

[0018] The lens device according to the above aspect may include: an EX group that can be inserted into and removed from the optical path of the zoom lens and changes the focal length through the insertion and removal; and an insertion / removal detection unit that detects the insertion / removal state, and the correction value may be configured to be set for each insertion / removal state.

[0019] When FNot is the open F-number in a state where the zoom lens is focused on an object at infinity at the telephoto end, ft is the focal length in a state where the zoom lens is focused on an object at infinity at the telephoto end, and fw is the focal length in a state where the zoom lens is focused on an object at infinity at the wide-angle end, the lens device according to the above aspect is characterized in that: 0.03 < FNot / (ft / fw) < 0.3 (5) it is preferable to satisfy conditional expression (5) represented by the above formula.

[0020] When fn is the focal length of the lens group having the strongest negative refractive power among the lens groups that have negative refractive power included in the zoom lens and move during zooming, and ft is the focal length in a state where the zoom lens is focused on an object at infinity at the telephoto end, the lens device according to the above aspect is characterized in that: -0.4 <fn / ft<-0.02 (6) It is preferable that the condition expressed in equation (6) is satisfied.

[0021] The first lens group of the zoom lens may be configured to consist of, in order from the object side to the image side, a first A subgroup having a negative refractive force that is fixed with respect to the image plane when focusing, a first B subgroup having a positive refractive force that moves along the optical axis when focusing, and a first C subgroup whose distance from the first B subgroup changes when focusing.

[0022] If Bf is the back focus of the zoom lens in air equivalent distance, fw is the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end, and ωw is the maximum half-angle of view when the zoom lens is in focus on an object at infinity at its wide-angle end, then the lens device of the above embodiment is: 4 <Bfw / (fw×tanωw)<10 (7) It is preferable that the condition (7) expressed by is satisfied.

[0023] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let the unit of f be mm. The correction value is the value at a specific image height defined as 0.49 × f × tanω. Among the rays incident on the image plane of the zoom lens at a specific image height, the ray that incident at an angle bisector of the angle between the upper ray and the lower ray is defined as the intermediate ray. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. Let Dexpw be the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is in focus on an object at infinity at its wide-angle end. If an optical element that does not have refractive power is placed between the image plane and the exit pupil position of the intermediate ray, Dexpw is calculated using the air equivalent distance for the optical element. In this case, the lens device of the above embodiment is: 4<|Dexpw / fw|<360 (8) It is preferable that the condition (8) expressed by is satisfied.

[0024] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. The correction value is the value at a specific image height defined as 0.49 × f × tanω. When the zoom lens is focused on an object at infinity, it is preferable that the exit pupil position of the principal ray at a specific image height is located on the image side of the image plane throughout the entire zoom range.

[0025] The imaging device of this disclosure comprises a lens device as described above and an imaging device body, the imaging device body including a color separation prism, an image sensor for capturing an image formed by a zoom lens, and a processing unit for performing a process to correct the color shading of image data based on correction data transmitted from the lens device.

[0026] Furthermore, the terms "~consisting of" and "~consisting of" in this specification are intended to include, in addition to the listed components, lenses that substantially have no refractive power, optical elements other than lenses such as apertures, filters, and cover glass, and mechanical parts such as lens flanges, lens barrels, image sensors, and image stabilization mechanisms.

[0027] In this specification, "a group of lenses having positive refractive power" means that the group as a whole has positive refractive power. Similarly, "a group of lenses having negative refractive power" means that the group as a whole has negative refractive power. "A lens having positive refractive power" and "a positive lens" are synonymous. "A lens having negative refractive power" and "a negative lens" are synonymous. In this specification, "a lens group" and "a focus group" are not limited to a configuration consisting of multiple lenses, but may also consist of a single lens.

[0028] In this specification, the number of lenses refers to the number of constituent lenses. For example, in a cemented lens formed by joining multiple single lenses of different materials, the number of lenses is expressed as the number of single lenses that make up the cemented lens. However, a composite aspherical lens (i.e., a lens in which a lens (e.g., a spherical lens) and an aspherical film formed on that lens are integrally constructed and function as a single aspherical lens as a whole) is not considered a cemented lens and is treated as a single lens. Unless otherwise specified, the sign of the refractive power and the surface shape for lenses including aspherical surfaces are those of the paraxial region.

[0029] In this specification, the "focal length" used in the conditional equations refers to the paraxial focal length. Unless otherwise specified, the values ​​used in the conditional equations are those obtained with the zoom lens focused on an object at infinity, with the d line as the reference.

[0030] The terms "d-line," "C-line," "F-line," and "g-line" used herein are emission lines. The wavelength of the d-line is treated as 587.56 nm (nanometers), the wavelength of the C-line as 656.27 nm (nanometers), the wavelength of the F-line as 486.13 nm (nanometers), and the wavelength of the g-line as 435.84 nm (nanometers). [Effects of the Invention]

[0031] According to this disclosure, it is possible to provide a lens device advantageous for correcting color shading, and an imaging device equipped with this lens device. [Brief explanation of the drawing]

[0032] [Figure 1] This is a functional configuration diagram of the imaging device according to the first embodiment. [Figure 2] This is a cross-sectional view of an example of a zoom lens configuration. [Figure 3] Figure 2 is a cross-sectional view showing the light beam and configuration of the zoom lens in each state. [Figure 4] This is a schematic diagram of an example of a three-plate color separation prism. [Figure 5]This figure shows an example of correction data. [Figure 6] This figure shows an example of the number of states included in the correction data. [Figure 7] This is a diagram to explain intermediate rays. [Figure 8] This is an enlarged view of region A in Figure 7. [Figure 9] This is a flowchart illustrating an example of the operation. [Figure 10] Here is another example of the operation in a flowchart. [Figure 11] This figure shows the relationship between focal length and Dexp. [Figure 12] This is a functional configuration diagram of the imaging device according to the second embodiment. [Figure 13] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 1. [Figure 14] These are aberration diagrams of the zoom lens of Example 1. [Figure 15] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration in Example 2. [Figure 16] These are aberration diagrams for the zoom lens of Example 2. [Figure 17] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration in Example 3. [Figure 18] These are aberration diagrams for the zoom lens of Example 3. [Figure 19] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration in Example 4. [Figure 20] These are aberration diagrams for the zoom lens of Example 4. [Figure 21] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 5. [Figure 22] These are aberration diagrams for the zoom lens of Example 5. [Figure 23] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 6. [Figure 24] These are aberration diagrams for the zoom lens of Example 6. [Figure 25]This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 7. [Figure 26] These are aberration diagrams for the zoom lens of Example 7. [Figure 27] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 8. [Figure 28] These are aberration diagrams for the zoom lens of Example 8. [Figure 29] This figure shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 9. [Figure 30] These are aberration diagrams for the zoom lens of Example 9. [Modes for carrying out the invention]

[0033] Embodiments of this disclosure will be described below with reference to the drawings.

[0034] [First Embodiment] Figure 1 shows a functional configuration diagram of an imaging device 100 according to the first embodiment of this disclosure. The imaging device 100 is, for example, a broadcast camera. The imaging device 100 comprises a lens device 10 and an imaging device body 50. The lens device 10 is detachably attached to the imaging device body 50 and can be mounted on the imaging device body 50 via a mount 40 provided on the imaging device body 50.

[0035] The lens device 10 has a zoom lens 1 that photographs a subject (not shown) and forms an image. The imaging device body 50 has a color separation prism 60 and an image sensor 68. With the lens device 10 mounted on the imaging device body 50, the imaging device body 50 can capture the image formed by the zoom lens 1 via the color separation prism 60 and the image sensor 68, and generates image data through this capture.

[0036] [Lens device configuration] The lens device 10 includes a zoom lens 1, a focus detection unit 12, a zoom detection unit 14, an aperture detection unit 16, a storage unit 20, and a communication unit 30.

[0037] Zoom lens 1 functions as an imaging lens and forms an image of the subject. Figure 1 conceptually shows zoom lens 1. Figure 2 shows a cross-sectional view of an example of zoom lens 1 at the wide-angle end. The example shown in Figure 2 corresponds to the zoom lens of Embodiment 1 described later. Figure 3 shows cross-sectional views of zoom lens 1 at each zoom state of Figure 2. In Figure 3, the upper section labeled "Wide" shows the wide-angle end state, the middle section labeled "Middle" shows the intermediate focal length state, and the lower section labeled "Tele" shows the telephoto end state. Figure 3 also shows the light beam, which is the axial light beam and the light beam of the maximum half-angle ωw at the wide-angle end, the axial light beam and the light beam of the maximum half-angle ωm at the intermediate focal length state, and the axial light beam and the light beam of the maximum half-angle ωt at the telephoto end. In Figures 2 and 3, the left side is the object side and the right side is the image side, showing the state when focused on an object at infinity.

[0038] Figure 3 schematically shows the color separation prism 60 positioned between the zoom lens 1 and the image plane Sim. In this example, the color separation prism 60 includes not only prism elements but also filters that reflect / transmit light of specific wavelengths. The detailed configuration of the color separation prism 60 will be described later.

[0039] The zoom lens 1 includes a first lens group G1 positioned closest to the object, a plurality of movable lens groups that move along the optical axis Z by changing the distance between adjacent lens groups during magnification, and a final lens group GE positioned closest to the image. Magnification of the zoom lens 1 is performed by the movement of the movable lens groups. During magnification, the first lens group G1 and the final lens group GE are fixed with respect to the image plane Sim. Because the lens group closest to the object and the lens group closest to the image are immobile with respect to the image plane Sim during magnification, fluctuations in the center of gravity during magnification can be suppressed. The above configuration is suitable as a video imaging lens to be used in an imaging optical system having a three-plate color separation prism, and is advantageous for correcting color shading.

[0040] An aperture diaphragm St is located inside the zoom lens 1. The aperture diaphragm St has an opening with a variable aperture size. By changing the aperture size of the aperture diaphragm 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 may be performed by user operation, or it may be configured to change in conjunction with the zoom level.

[0041] As an example, the zoom lens 1 in Figure 2 is configured as follows. The zoom lens 1 consists of, in order from the object side to the image side, 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 eight lenses, L11 to L18, in order from the object side to the image side. The second lens group G2 consists of one lens, L21. The third lens group G3 consists of five lenses, L31 to L35, in order from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 to L42, in order from the object side to the image side. The final lens group GE consists of the aperture diaphragm St and nine lenses, L51 to L59, in order from the object side to the image side. The aperture diaphragm St shown in Figure 2 indicates its position in the optical axis direction, not its size or shape. In the example shown in Figure 2, the second lens group G2, the third lens group G3, and the fourth lens group G4 are examples of the "movable lens groups" of this disclosure. In Figure 2, below the lens groups corresponding to the movable lens groups, the approximate movement trajectories of each movable lens group when changing magnification from the wide-angle end to the telephoto end are shown by curved arrows.

[0042] The first lens group G1 is configured to include a focusing group. The focusing group is a group that moves along the optical axis Z when focusing occurs. The movement of the focusing group enables the zoom lens 1 to focus. By positioning the lenses of the first lens group G1, which is fixed to the object side and is positioned closer to the object than the moving lens group that moves during zoom variation, and using the fixed lenses of the first lens group G1 to achieve focusing during zoom variation, zoom variation and focusing can be made independent. This makes it possible to create a lens configuration suitable for video lenses.

[0043] In the example in Figure 2, the first lens group G1 consists of, in order from the object side to the image side, a first A subgroup G1A having a negative refractive force fixed to the image plane Sim when in focus, a first B subgroup G1B having a positive refractive force that moves along the optical axis Z when in focus, and a first C subgroup G1C whose distance from the first B subgroup G1B changes when in focus. In other words, in the example in Figure 2, the first B subgroup G1B corresponds to the focus group. In Figure 2, a horizontal double arrow is shown below the group corresponding to the focus group. In the example in Figure 2, the first A subgroup G1A consists of lenses L11 to L13, the first B subgroup G1B consists of lenses L14 to L16, and the first C subgroup G1C consists of lenses L17 to L18.

[0044] The movement of the focus group, the movement of the movable lens group, and the variation in the aperture amount of the aperture diaphragm St are performed by a drive unit (not shown) including an actuator such as a linear motor, a stepping motor, or a voice coil motor.

[0045] The focus detection unit 12 detects the position of the focus group along the optical axis and uses this detected position to detect the focus state of the zoom lens 1. The focus state may be expressed, for example, using the distance between the subject in focus of the zoom lens 1 and the zoom lens 1. The focus detection unit 12 is configured to include, for example, an encoder such as a photointerrupter and / or a magnetic sensor.

[0046] The zoom detection unit 14 detects the position of each moving lens group along the optical axis and uses this detected position to detect the zoom state of the zoom lens 1. The zoom state refers to the magnification state. The wide-angle end state and the telephoto end state are each one zoom state. The zoom state may also be expressed using, for example, the focal length of the entire zoom lens 1. The zoom detection unit 14 is configured to include, for example, an encoder such as a photointerrupter and / or a magnetic sensor.

[0047] The aperture detection unit 16 detects the aperture amount of the aperture diaphragm St and uses this detected aperture amount to detect the aperture state of the zoom lens 1. The aperture state may be represented, for example, using the effective F-number of the zoom lens 1. The aperture detection unit 16 is configured to include, for example, an encoder such as a photointerrupter and / or a magnetic sensor.

[0048] The storage unit 20 stores correction data 22. The correction data 22 is data used to correct the color shading of image data obtained by imaging with the imaging device body 50. The correction data 22 will be described in detail later. The storage unit 20 is composed of, for example, non-volatile memory such as flash memory.

[0049] The communication unit 30 communicates with the imaging device body 50. When the lens device 10 is mounted on the mount 40, the lens device 10 and the imaging device body 50 are electrically connected, and this electrical connection enables the communication unit 30 in the lens device 10 and the communication unit 80 in the imaging device body 50 to communicate with each other. The communication unit 30 transmits the status of the lens device 10 and the correction data 22 to the imaging device body 50. Note that "transmitting the correction data 22" includes not only the transmission of the entire correction data, but also the transmission of only a part of the correction data 22.

[0050] In the lens device 10, each part is controlled and various processes are executed by a processor (not shown). This processor consists of, for example, a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0051] [Configuration of the imaging device body] The imaging device body 50 includes a color separation prism 60 and an image sensor 68, as well as a processing unit 70, a communication unit 80, and a display unit 90.

[0052] The color separation prism 60 is a prism that separates an incident light beam into multiple colored light beams and emits them. In an imaging device that uses three solid-state image sensors for red, green, and blue light, the color separation prism 60 is used to separate the imaging light beam into the three primary colors of red, green, and blue, and then directs it into the solid-state image sensor for each color.

[0053] Figure 4 shows a schematic diagram of an example of a color separation prism 60. The color separation prism 60 in Figure 4 is a three-plate color separation prism that separates an incident light beam L into three colors, and is an optical component that does not have refractive power. The color separation prism 60 has three prism members arranged in order from the light incident side: a first prism member 61, a second prism member 62, and a third prism member 63. A first optical filter 64 for color separation is formed at the interface between the first prism member 61 and the second prism member 62, and a second optical filter 65 for color separation is formed at the interface between the second prism member 62 and the third prism member 63.

[0054] In the color separation prism 60 shown in Figure 4, the first optical filter 64 is positioned at an angle such that the incident light beam L is incident at a predetermined angle of incidence, 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 positioned at a predetermined angle of inclination relative to the first optical filter 64, 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.

[0055] The first prism member 61 is provided with a blue light transmission filter 61B that transmits only blue light LB on its light-emitting surface. The second prism member 62 is provided with a red light transmission filter 62R that transmits only red light LR on its light-emitting surface. The third prism member 63 is provided with a green light transmission filter 63G that transmits only green light LG on its light-emitting surface.

[0056] After the incident light beam L enters the first prism member 61, the blue light LB is reflected by the first optical filter 64, while the green light LG and red light LR are transmitted. The blue light LB reflected by the first optical filter 64 is totally internalized at the incident surface of the first prism member 61 and then emitted towards a blue light solid-state image sensor (not shown) via the blue light transmission filter 61B.

[0057] Red light LR that has passed through the first optical filter 64 is reflected by the second optical filter 65 and emitted towards a red light solid-state image sensor (not shown) via a red light transmission filter 62R. Green light LG that has passed through the first optical filter 64 passes through the second optical filter 65 and is emitted towards a green light solid-state image sensor (not shown) via a green light transmission filter 63G.

[0058] In Figure 4, for ease of understanding, the incident light beam L to the color separation prism 60 is schematically shown with three horizontal arrows. However, since the actual imaging light beam passes through the zoom lens 1, the imaging light beam incident to the color separation prism 60 includes not only rays perpendicular to the incident plane but also rays incident at various angles of incidence.

[0059] Generally, optical multilayer films exhibit an incident angle dependence, with the spectral characteristics tending to shift towards shorter wavelengths as the incident angle increases. Also, generally, the transmittance value tends to decrease as the incident angle increases. Therefore, the amount of light reflected or transmitted differs between light incident at a high incident angle and light incident at a low incident angle. Since the first optical filter 64 and the second optical filter 65 are composed of optical multilayer films, the light that passes through the color separation prism 60 exhibits a phenomenon called "color shading," where the color tone differs in the vertical direction of the image due to the aforementioned incident angle dependence. In this specification, "vertical direction of the image" refers to the direction perpendicular to the optical axis.

[0060] In particular, because green light (LG) is separated by passing through two optical filters, the first optical filter 64 and the second optical filter 65, the angle-dependent characteristics of the light intensity of green light (LG) are stronger compared to blue light (LB) and red light (LR). As a result, for example, green increases and red and blue decreases in the peripheral areas of the captured image. In particular, green light has a strong effect on brightness; brightness is high where the amount of transmitted green light is high, and conversely, brightness is low where the amount is low. This can also cause a phenomenon called "luminance shading," where the brightness differs in the vertical direction of the screen.

[0061] In the imaging device body 50, the imaging light beam that has passed through the color separation prism 60 is incident on the image sensor 68. The imaging surface of the image sensor 68 is positioned at the same location as the image plane Sim of the zoom lens 1. The image sensor 68 captures the image formed by the zoom lens 1, generates image data from this capture, and outputs it to the processing unit 70. As the image sensor 68, for example, a solid-state image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) can be used.

[0062] The processing unit 70 processes the signal output from the image sensor 68 to generate output image data. In addition, when generating output image data, the processing unit 70 performs a process to correct the color shading of the image data based on the correction data 22 transmitted from the lens device 10 and acquired via the communication unit 80.

[0063] The communication unit 80 communicates with the communication unit 30 of the lens device 10. The correction data 22 transmitted from the lens device 10 to the imaging device body 50 by the communication unit 30 is received by the communication unit 80 and transmitted to the processing unit 70.

[0064] The display unit 90 displays output image data generated by the processing unit 70. The display unit 90 is composed of, for example, a liquid crystal monitor.

[0065] The imaging device body 50 is configured to include an operating section (not shown) that receives user input. The operating section consists of, for example, a zoom button, a shutter release button, a dial, a cross-shaped or control wheel-type selection button, and a touch panel provided on the display.

[0066] In the imaging device body 50, each part is controlled and various processes are executed by a processor (not shown). This processor is composed of, 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.

[0067] [Correction data] The correction data 22 has correction values ​​set for each combination of the zoom state, focus state, and aperture state of the zoom lens 1. That is, the correction data 22 has multiple combinations of zoom state, focus state, and aperture state, and one corresponding correction value is set for each combination. This configuration is advantageous in suppressing the size of the correction data 22.

[0068] The correction data 22 may be stored as table data. As an example, Figure 5 shows an example of correction data 22 stored as table data. The correction data 22 in Figure 5 has correction values ​​v1, v2, v3, ... set for each combination of zoom state z1, z2, ..., focus state foc1, foc2, and aperture state a1, a2.

[0069] In order to obtain a suitable color shading correction effect while suppressing the size of the correction data 22, it is preferable to satisfy at least one of the following conditional equations (2), (3), and (4). Here, in each group of combinations of the correction data 22, Nz is the number of zoom states, Nf is the number of focus states, and Na is the number of aperture states. 0.05 ≤ Nf / (Nz × Na) ≤ 0.3 (2) 8 ≤ (Nz × Nf) / Na ≤ 256 (3) 256 ≤ Nz × Nf × Na ≤ 2048 (4)

[0070] By ensuring that the corresponding value in conditional equation (2) does not fall below the lower limit, the number of focus states in the correction data 22 can be secured, making it easier to prevent insufficient correction when correcting color shading caused by changes in the focus state. By ensuring that the corresponding value in conditional equation (2) does not exceed the upper limit, the proportion of focus states in the correction data 22 does not become too large, making it easier to prevent insufficient correction when correcting color shading caused by changes in the zoom state and aperture state.

[0071] To obtain better characteristics, the lower limit of condition (2) is more preferably 0.0625, even more preferably 0.1, and even more preferably 0.125. To obtain better characteristics, the upper limit of condition (2) is more preferably 0.25. For example, it is more preferable to satisfy the following condition (2-1) instead of condition (2), even more preferable to satisfy the following condition (2-2), and even more preferable to satisfy the following condition (2-3). 0.0625 ≤ Nf / (Nz × Na) ≤ 0.25 (2-1) 0.1 ≤ Nf / (Nz × Na) ≤ 0.25 (2-2) 0.125 ≤ Nf / (Nz × Na) ≤ 0.25 (2-3)

[0072] By ensuring that the corresponding value in conditional equation (3) does not fall below the lower limit, the proportion of aperture states in the correction data 22 does not become too large, making it easier to prevent insufficient correction when correcting color shading caused by changes in zoom and focus states. By ensuring that the corresponding value in conditional equation (3) does not exceed the upper limit, the number of aperture states in the correction data 22 can be ensured, making it easier to prevent insufficient correction when correcting color shading caused by changes in aperture states.

[0073] To obtain better characteristics, the lower limit of condition (3) is more preferably 16, even more preferably 20, even more preferably 24, and even more preferably 32. To obtain better characteristics, the upper limit of condition (3) is more preferably 128, even more preferably 64. For example, it is more preferable to satisfy the following condition (3-1) instead of condition (3), even more preferably to satisfy the following condition (3-2), even more preferably to satisfy the following condition (3-3), and even more preferably to satisfy the following condition (3-4). 16 ≤ (Nz × Nf) / Na ≤ 128 (3-1) 20 ≤ (Nz × Nf) / Na ≤ 128 (3-2) 24 ≤ (Nz × Nf) / Na ≤ 128 (3-3) 32 ≤ (Nz × Nf) / Na ≤ 64 (3-4)

[0074] It is preferable that the lens device 10 simultaneously satisfies conditions (2) and (3). Changes in the angle of incidence of light rays to the imaging plane are caused by changes in each state of the zoom lens 1, but are most significantly affected in the order of changes in zoom state, focus state, and aperture state. By simultaneously satisfying conditions (2) and (3), the number of focus states and aperture states can be kept within a suitable range, thereby effectively correcting color shading while keeping the size of the correction data 22 down.

[0075] By ensuring that the corresponding value in condition (4) does not fall below the lower limit, it becomes easier to prevent insufficient color shading correction. By ensuring that the corresponding value in condition (4) does not exceed the upper limit, it is possible to suppress the size of the correction data 22 from becoming excessive. By satisfying condition (4), it is possible to effectively correct color shading while keeping the size of the correction data 22 down.

[0076] To obtain better characteristics, the lower limit of condition (4) is more preferably 320, even more preferably 384, and even more preferably 448. To obtain better characteristics, the upper limit of condition (4) is more preferably 1600, even more preferably 1296, and even more preferably 1024. For example, it is more preferable to satisfy the following condition (4-1) instead of condition (4), even more preferable to satisfy the following condition (4-2), and even more preferable to satisfy the following condition (4-3). 320 ≤ Nz × Nf × Na ≤ 1600 (4-1) 384 ≤ Nz × Nf × Na ≤ 1296 (4-2) 448 ≤ Nz × Nf × Na ≤ 1024 (4-3)

[0077] Figure 6 shows examples of Nz, Nf, and Na in each combination group, and the corresponding values ​​of conditional equations (2), (3), and (4) calculated from these examples.

[0078] The correction value in the correction data 22 is preferably a value at a predetermined image height. Hereinafter, this predetermined image height will be referred to as the "specific image height". In this disclosure, the "specific image height" is defined as 0.49 × f × tanω, where f and ω are the focal length and maximum half-angle of view of the zoom lens 1 in each zoom state, respectively, and the unit of f is mm (millimeters). The specific image height preferably satisfies the following condition (1). 1.5 mm < 0.49 × f × tanω < 5 mm (1)

[0079] By ensuring that the corresponding value in condition (1) does not fall below the lower limit, it becomes easier to prevent insufficient correction of color shading. By ensuring that the corresponding value in condition (1) does not exceed the upper limit, it becomes easier to prevent overcorrection of color shading. By satisfying condition (1), it becomes easier to effectively correct the vertical color shading on the screen of the captured image.

[0080] To obtain better characteristics, the lower limit of condition (1) is more preferably 1.7 mm, even more preferably 1.9 mm, and even more preferably 2.1 mm. To obtain better characteristics, the upper limit of condition (1) is more preferably 3.5 mm, even more preferably 3.2 mm, and even more preferably 3 mm. For example, it is more preferable to satisfy the following condition (1-1) instead of condition (1), even more preferable to satisfy the following condition (1-2), and even more preferable to satisfy the following condition (1-3). 1.7mm<0.49×f×tanω<3.5mm (1-1) 1.9mm<0.49×f×tanω<3.2mm (1-2) 2.1mm<0.49×f×tanω<3mm (1-3)

[0081] Specifically, the correction value may be set as, for example, the distance on the optical axis between the exit pupil position of a ray incident on a particular image height of the image plane Sim and the image plane Sim. There are many rays incident on a particular image height, and among them, the principal ray (i.e., the ray passing through the center of the aperture diaphragm St) may be used, the ray passing through the centroid position of the spot diagram may be used, or the intermediate rays described below may be used.

[0082] For the sake of explanation, in this specification, among the light rays incident at a particular image height, the ray that enters at an angle bisector of the angle between the upper and lower rays is referred to as the "intermediate ray." Intermediate rays will be explained with reference to Figures 7 and 8.

[0083] Figure 7 shows the upper ray Ry1 and lower ray Ry2 incident on a specific image height Ys when the zoom lens 1 shown in Figure 2 is focused on an object at infinity at its wide-angle end. The upper ray Ry1 is the ray that is furthest from the optical axis Z within a single cross-section containing the optical axis Z, and the lower ray Ry2 is the ray that is closest to the optical axis Z within the same cross-section containing the optical axis Z, among the rays incident on the specific image height Ys. The terms "far from the optical axis Z" and "close to the optical axis Z" are determined in the vicinity of the image plane Sim of the zoom lens 1.

[0084] In Figure 7, the region A near the image plane Sim is shown with a dashed line, and Figure 8 shows a magnified view of this region A. In Figures 7 and 8, the color separation prism 60 is shaded for ease of understanding. Figure 8 shows the 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, Figure 7 shows the exit pupil position Pexpw of the intermediate ray Ry3.

[0085] In the technology disclosed herein, the ray used to set the correction value is not limited to a ray incident at a specific image height. For example, the correction value may be the distance from the image plane Sim to the paraxial exit pupil position. Furthermore, it is preferable to appropriately determine what value to use as the correction value according to the required specifications. For example, the correction value may be the incident angle of a ray incident on the imaging plane. Even when the correction value is the incident angle of a ray incident on the imaging plane, this ray may be the principal ray at a specific image height, a ray passing through the centroid position of the spot diagram of the light beam incident at a specific image height, or one of the intermediate rays mentioned above.

[0086] Furthermore, the correction values ​​are not limited to actual values ​​such as actual distance and actual angle; values ​​obtained by converting actual values ​​may also be used. Examples of such conversions include proportional conversion, exponential conversion, number base conversion, 8-bit conversion, and 16-bit conversion.

[0087] [Example of operation] Next, an example of the operation of this embodiment will be described with reference to the flowchart in Figure 9.

[0088] In step S10, the lens device 10 is mounted on the imaging device body 50. The user, as needed, operates the control units (not shown) on the imaging device body 50 and / or the lens device 10 to change the zoom state, focus state, and / or aperture state of the zoom lens 1.

[0089] In step S20, the user photographs a subject using the zoom lens 1. The image sensor 68 captures the image formed by the zoom lens 1, generates image data, and outputs it to the processing unit 70.

[0090] In step S30, each detection unit of the lens device 10 detects the respective states 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.

[0091] In step S40, the lens device 10 transmits the detected focus state, zoom state, and aperture state to the imaging device body 50 via the communication unit 30. The lens device 10 also retrieves a single correction value set for each detected state combination from the storage unit 20 and transmits it to the imaging device body 50 via the communication unit 30. The processing unit 70 of the imaging device body 50 receives each state and correction value via the communication unit 30 and the communication unit 80.

[0092] In step S50, the processing unit 70 performs color shading correction on the image data based on the received correction value, generates output image data, and outputs it to the display unit 90. The display unit 90 displays the output image data.

[0093] In step S40 of the above operation, the lens device 10 transmits one correction value corresponding to each detected combination of states. However, the present invention is not limited to the above example. For example, the lens device 10 may transmit all correction values ​​before detecting each state. An example of operation different from that shown in Figure 9 will be described with reference to the flowchart in Figure 10.

[0094] In step S210, the lens device 10 is mounted on the imaging device body 50. The user, as needed, operates the control units (not shown) on the imaging device body 50 and / or the lens device 10 to change the zoom state, focus state, and / or aperture state of the zoom lens 1.

[0095] In step S220, the lens device 10 transmits all of the correction data 22 for color shading correction to the imaging device body 50 via the communication unit 30. The processing unit 70 of the imaging device body 50 receives the correction data 22 via the communication unit 30 and the communication unit 80.

[0096] In step S230, the user photographs a subject using the zoom lens 1. The image sensor 68 captures the image formed by the zoom lens 1, generates image data, and outputs it to the processing unit 70.

[0097] In step S240, each detection unit of the lens device 10 detects the respective states 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.

[0098] In step S250, the lens device 10 transmits the detected focus state, zoom state, and aperture state to the imaging device body 50 via the communication unit 30. The processing unit 70 of the imaging device body 50 receives each state of the zoom lens 1 via the communication unit 30 and the communication unit 80.

[0099] In step S260, the processing unit 70 reads the correction values ​​set for each of the received state combinations from the correction data 22 received in step S220, performs color shading correction on the image data based on the read correction values, generates output image data, and outputs it to the display unit 90. The display unit 90 displays the output image data.

[0100] Note that since the values ​​for each state in the correction data are discrete, the detected state value may not match the values ​​for each state in the correction data. In such cases, the closest value from the correction data may be used as a substitute, or a correction value may be created by interpolation, and color shading correction may be performed based on this created correction value.

[0101] [Zoom lens configuration] Next, preferred and possible configurations of the zoom lens used in the technology of this disclosure will be described. In the following description, “specific image height” refers to the image height defined as 0.49 × f × tanω as described above. Also, in the following description, to avoid redundant explanations, the same symbols will be used for things with the same definition, and redundant explanations of symbols will be omitted.

[0102] In a zoom lens, when focused on an object at infinity, it is preferable that the exit pupil position of the principal ray at a specific image height is located on the image side of the image plane throughout the entire zoom range. This is a characteristic that arises from a lens configuration suitable for motion-capable lenses used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0103] When Dexp is the distance from the image plane of a zoom lens to the exit pupil position of the intermediate ray, ft is the focal length at the telephoto end of the zoom lens, and fw is the focal length at the wide-angle end of the zoom lens, it is preferable that the zoom lens be configured as follows: The focal length of the zoom lens when Dexp at the wide-angle end is negative, Dexp at the telephoto end is positive, and Dexp is at infinity is fw × (ft / fw). 0.6 The above and fw×(ft / fw) 0.9It is preferable that the values ​​are within the following range. Note that the sign of Dexp is positive for distances on the image side and negative for distances on the object side, with the image plane of the zoom lens as the reference. Also, Dexp, ft, and fw are the values ​​when the zoom lens is focused on an object at infinity. As described above, by making the value of Dexp negative at the wide-angle end, at infinity in the intermediate range, and positive at the telephoto end, the absolute value of Dexp can be increased throughout the entire zoom range. This makes it easier to reduce the angle of incidence of the light rays entering the color separation prism 60 from the zoom lens 1, which is advantageous for correcting color shading.

[0104] As an example, Figure 11 shows the relationship between the focal length and Dexp of the zoom lens in Example 1, which will be described later. In Figure 11, the horizontal axis represents the focal length, the vertical axis represents Dexp, and the units of both the horizontal and vertical axes are mm (millimeters). The data for Example 1 in Table 27, described later, is plotted. Plot P1 in Figure 11 shows the value at the wide-angle end, and plot P8 shows the value at the telephoto end. In Figure 11, fw × (ft / fw) 0.6 The corresponding focal length, and fw × (ft / fw) 0.9 The corresponding focal length is shown by a dashed line. The area enclosed by the two dashed lines in Figure 11 is where the focal length is fw × (ft / fw). 0.6 The above and fw×(ft / fw) 0.9 The following range exists, and plots P6 and P7 are located within this range. The Dexp of plot P6 is a negative value, and the Dexp of plot P7 is a positive value. In Example 1 described later, there exists a focal length between the focal length of plot P6 and the focal length of plot P7 where Dexp is at infinity.

[0105] When the zoom lens is focused on an object at infinity at its wide-angle end, and Dexpw is the distance from the image plane to the exit pupil position of the intermediate ray, it is preferable that the zoom lens satisfies the following condition (8). If an optical element that does not have refractive power is placed between the image plane Sim and the exit pupil position of the intermediate ray, Dexpw will be calculated using the air equivalent distance for that optical element. By ensuring that the corresponding value of condition (8) does not fall below the lower limit, it is advantageous to reduce the incident angle of the light rays incident on the imaging plane, thus making it an optical system suitable for imaging optical systems with a three-plate color separation prism. By ensuring that the corresponding value of condition (8) does not exceed the upper limit, it is easy to shorten the overall length of the optical system, which is advantageous for miniaturization. 4<|Dexpw / fw|<360 (8)

[0106] To obtain better characteristics, the lower limit of condition (8) is more preferably 6, even more preferably 8, and even more preferably 10. To obtain better characteristics, the upper limit of condition (8) is more preferably 200, even more preferably 100, and even more preferably 50. For example, it is more preferable to satisfy the following condition (8-1) instead of condition (8), even more preferable to satisfy the following condition (8-2), and even more preferable to satisfy the following condition (8-3). 6 < |Dexpw / fw| < 200 (8-1) 8 < |Dexpw / fw| < 100 (8-2) 10 < |Dexpw / fw| < 50 (8-3)

[0107] When the maximum aperture F-number when the zoom lens is focused on an object at infinity at its telephoto end is denoted as FNot, it is preferable that the zoom lens satisfies the following condition (5). By ensuring that the corresponding value in condition (5) does not fall below the lower limit, it becomes advantageous to miniaturize the entire optical system, or it becomes easier to suppress various aberrations, especially at the telephoto end. By ensuring that the corresponding value in condition (5) does not exceed the upper limit, it becomes easier to obtain sufficient brightness at the telephoto end, or it becomes possible to obtain a high-magnification optical system. 0.03 <FNot / (ft / fw)<0.3 (5)

[0108] To obtain better characteristics, the lower limit of condition (5) is more preferably 0.04, and even more preferably 0.05. To obtain better characteristics, the upper limit of condition (5) is more preferably 0.25, and even more preferably 0.2. For example, it is more preferable to satisfy the following condition (5-1) instead of condition (5), and even more preferable to satisfy the following condition (5-2). 0.04 <FNot / (ft / fw)<0.25 (5-1) 0.05 <FNot / (ft / fw)<0.2 (5-2)

[0109] In a zoom lens, if the focal length of the lens group with the strongest negative refractive power among the lens groups that have negative refractive power and move during magnification is fn, it is preferable that the zoom lens satisfies the following condition (6). By ensuring that the corresponding value in condition (6) does not fall below the lower limit, sufficient refractive power for magnification can be secured, which is advantageous for obtaining a high-magnification optical system. By ensuring that the corresponding value in condition (6) does not exceed the upper limit, it is advantageous for suppressing various aberrations at the telephoto end. -0.4 <fn / ft<-0.02 (6)

[0110] To obtain better characteristics, the lower limit of condition (6) is more preferably -0.35, and even more preferably -0.3. To obtain better characteristics, the upper limit of condition (6) is more preferably -0.03, and even more preferably -0.04. For example, it is more preferable to satisfy the following condition (6-1) instead of condition (6), and even more preferable to satisfy the following condition (6-2). -0.35 <fn / ft<-0.03 (6-1) -0.3 <fn / ft<-0.04 (6-2)

[0111] If Bf is the air-equivalent back focus of a zoom lens, and ωw is the maximum half-angle of view when the zoom lens is in focus on an object at infinity at its wide-angle end, it is preferable that the zoom lens satisfies the following condition (7). By ensuring that the corresponding value in condition (7) does not fall below the lower limit, the back focus does not become too short, making it an optical system suitable for an imaging optical system with a three-chip color-resolving prism. By ensuring that the corresponding value in condition (7) does not exceed the upper limit, the back focus does not become too long, which is advantageous for miniaturization. 4 <Bfw / (fw×tanωw)<10 (7)

[0112] To obtain better characteristics, the lower limit of condition (7) is more preferably 4.5, and even more preferably 5. To obtain better characteristics, the upper limit of condition (7) is more preferably 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 preferable to satisfy the following condition (7-2). 4.5 <Bfw / (fw×tanωw)<9 (7-1) 5 <Bfw / (fw×tanωw)<8 (7-2)

[0113] A zoom lens may be configured to consist of, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power that moves during magnification, one to three lens groups that move by changing the distance between adjacent lens groups during magnification, and a final lens group having positive refractive power. This configuration is suitable for high-magnification video lenses used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0114] 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 in order from the object side to the image side. When the magnification is changed, the second and third lens groups may be configured to move while changing their relative distance. This configuration is suitable for high-magnification video lenses with a wide-angle focal length at the wide-angle end, which are used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0115] The zoom lens consists of, in order from the object side to the image side, 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. When changing magnification, the second, third, and fourth lens groups may be configured to move by changing the distance between them and adjacent lens groups. This configuration is suitable for high-magnification video lenses with a wide-angle focal length close to standard, which are used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0116] The zoom lens consists of, in order from the object side to the image side, 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. When the magnification is changed, the second, third, and fourth lens groups may be configured to move by changing the distance between them and adjacent lens groups. This configuration is suitable for high-magnification video lenses used in imaging optical systems with a three-plate color-resolving prism, where the focal length at the wide-angle end is close to wide-angle and the focal length at the telephoto end is super-telephoto, and is advantageous for correcting color shading.

[0117] The zoom lens consists of, in order from the object side to the image side, 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. When changing magnification, the second, third, fourth, and fifth lens groups may be configured to move by changing the distance between them and adjacent lens groups. This configuration is suitable for high-magnification video lenses with a wide-angle focal length close to standard, which are used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0118] The zoom lens consists of, in order from the object side to the image side, 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. When changing magnification, the second, third, fourth, and fifth lens groups may be configured to move by changing the distance between them and adjacent lens groups. This configuration is suitable for high-magnification video lenses with a wide-angle focal length close to standard, which are used in imaging optical systems with a three-plate color-resolving prism, and is advantageous for correcting color shading.

[0119] The zoom lens consists of, in order from the object side to the image side, 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. When changing magnification, the second, third, fourth, and fifth lens groups may be configured to move by changing the distance between them and adjacent lens groups. This configuration is suitable for high-magnification video lenses with a wide-angle focal length close to standard and a magnification exceeding 40x, and is advantageous for correcting color shading, and is used in imaging optical systems with a three-plate color separation prism.

[0120] In this specification, a lens group is defined as a group whose distance in the optical axis direction changes when the magnification is varied. Within a single lens group, the distance between adjacent lenses does not change when the magnification is varied. That is, a "lens group" is a component of a zoom lens that includes at least one lens and is separated by the air gap that changes when the magnification is varied. When the magnification is varied, each lens group is moved or fixed. A "lens group" may include components other than lenses that do not have refractive power, such as an aperture diaphragm.

[0121] The aperture diaphragm may be positioned closest to the object in the final lens group, or it may be configured to be included in the moving lens group.

[0122] The first lens group may be configured to consist of, in order from the object side to the image side, a first A subgroup having a negative refractive force that is fixed to the image plane when focusing, a first B subgroup having a positive refractive force that moves along the optical axis Z when focusing, and a first C subgroup G1C that moves while changing the distance between itself and the first B subgroup G1B when focusing.

[0123] The preferred and possible configurations described above, including those relating to conditional expressions, can be combined in any way within the bounds of consistency, and are preferably selected selectively as appropriate according to the required specifications.

[0124] [Second Embodiment] Figure 12 shows a functional configuration diagram of the imaging device 200 according to the second embodiment of this disclosure. The second embodiment differs significantly from the first embodiment in that the zoom lens includes an EX group EX that can be inserted into and removed from the optical path, and the lens device includes an insertion / removal detection unit that detects 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 the same configurations will not be described.

[0125] The imaging device 200 comprises a lens device 210 and an imaging device body 50. The lens device 210 is detachable from the imaging device body 50 and can be mounted on the imaging device body 50 via a mount 40 provided on the imaging device body 50.

[0126] The lens device 210 includes a zoom lens 201, a focus detection unit 12, a zoom detection unit 14, an aperture detection unit 16, an insertion / removal detection unit 218, a storage unit 220, and a communication unit 30.

[0127] The zoom lens 201 functions as an imaging lens and forms an image of the subject. Figure 12 conceptually shows the zoom lens 201. The zoom lens 201 may be configured to include, for example, the zoom lens 1 of the first embodiment and an EX group EX that can be inserted into or removed from the optical path of the zoom lens 1. The focal length of the zoom lens 201 changes by inserting or removing the EX group EX.

[0128] The EX group EX can be configured, for example, as an extender lens that, when inserted into the optical path, increases the focal length of the lens system after insertion compared to the lens system before insertion. It is preferable that the image formation position remains constant even when the EX group EX is inserted or removed. The maximum image height may be configured to remain constant even when the EX group EX is inserted or removed, or it may be configured to change with the insertion or removal of the EX group EX. Note that "remains constant" as used herein includes cases where it remains constant including errors that are generally acceptable in the field to which the technology of this disclosure belongs.

[0129] The insertion / removal detection unit 218 detects the insertion / removal status of EX group EX.

[0130] The memory unit 220 stores correction data 222. The correction data 222 is data for correcting the color shading of image data obtained by imaging with the imaging device body 50. The correction data 222 has a correction value set for each of several combinations of the zoom state, focus state, and aperture state of the zoom lens 1, and furthermore, this correction value is set for each insertion / removal state of the EX group EX. The angle of incidence of the light rays used for imaging to the imaging plane differs depending on the insertion / removal state of the EX group EX. Therefore, by having a separate correction value for each insertion / removal state of the EX group EX and switching the correction value based on this insertion / removal state, more accurate correction becomes possible.

[0131] Except for the fact that the correction value is set for each insertion / removal state of EX group EX, the correction data 222 of the second embodiment can be considered in the same way as the correction data 22 of the first embodiment. That is, the preferred and possible configurations of the correction value of the second embodiment can also be considered in the same way as the correction value of the first embodiment.

[0132] In the second embodiment, when the lens device 210 transmits the status of each state of the zoom lens to the imaging device body 50, the zoom state, focus state, aperture state, and insertion / removal state of EX group EX are transmitted. The processing unit 70 of the imaging device body 50 performs color shading correction based on correction values ​​set for the combination of the zoom state, focus state, aperture state, and insertion / removal state of EX group EX.

[0133] [Examples of zoom lenses] Next, embodiments of the zoom lens of this disclosure will be described with reference to the drawings. Note that the reference numerals assigned to each group in the cross-sectional view of each embodiment are used independently for each embodiment to avoid complexity in the explanation and drawings due to the increasing number of digits in the reference numerals. Therefore, even if the same reference numerals are assigned to drawings of different embodiments, they do not necessarily represent the same configuration.

[0134] [Example 1] Figure 13 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 1. In Figure 13, the upper section labeled "Wide" shows the wide-angle end state, and the lower section labeled "Tele" shows the telephoto end state. Between the upper and lower sections, solid arrows show the approximate movement trajectory of each lens group that moves during magnification from the wide-angle end to the telephoto end. In Figure 13, the luminous flux is shown as the axial luminous flux and the luminous flux of the maximum half-angle at the wide-angle end, and the axial luminous flux and the luminous flux of the maximum half-angle at the telephoto end.

[0135] The zoom lens of Example 1 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having negative refractive power, and a final lens group GE having positive refractive power.

[0136] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The focusing group consists of the G1B subgroup. When focusing from an object at infinity to a nearby object, the G1B subgroup moves towards the image side, while the other groups remain fixed relative to the image plane Sim. The brackets and horizontal arrows attached to the G1B subgroup in Figure 13 indicate that the G1B subgroup is the focusing group and the direction in which it moves when focusing from an object at infinity to a nearby object. This method of illustrating the focusing group is the same in the figures of other embodiments.

[0137] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0138] For the zoom lens of Example 1, the basic lens data is shown in Tables 1A and 1B, the specifications and variable plane spacing are shown in Table 2, and the aspherical coefficient is shown in Table 3. In this specification, the basic lens data is shown in two separate tables to avoid making a single table too long.

[0139] The basic lens data table is as follows: The "Sn" column shows the surface number, where the surface closest to the object is designated as the first surface, and the number increases by one as you move towards the image side. The "R" column shows the radius of curvature of each surface. The "D" column shows the interplanar spacing on the optical axis between each surface and the surface adjacent to it on the image side. The "Nd" column shows the refractive index of each component with respect to the d line. The "νd" column shows the Abbe number of each component with respect to the d line. The "θg,F" column shows the partial dispersion ratio between the g line and the F line of each component. The "ED" column shows the maximum effective diameter of each surface.

[0140] Furthermore, if the refractive indices of a lens for the g-line, F-line, and C-line are Ng, NF, and NC, respectively, and the partial dispersion ratios between the g-line and F-line of that lens are θg and F, then θg and F are defined by the following equations. θg,F=(Ng-NF) / (NF-NC)

[0141] In the basic lens data table, the sign of the radius of curvature of a surface with a convex shape facing the object is positive, and the sign of the radius of curvature of a surface with a convex shape facing the image is negative. The basic lens data table also shows the aperture diaphragm St and the chromatic separation prism 60. In the column for the surface number corresponding to the aperture diaphragm St, the surface number and the phrase (St) are entered. The value in the bottom column of column D in Table 1B is the distance between the image-side surface in the table and the image plane Sim. For variable surface spacing during magnification, the symbol DD[ ] is used, and the object-side surface number for this spacing is placed inside the [ ] and entered in the surface spacing column.

[0142] Table 2 shows the zoom ratio Zr, focal length f, maximum aperture F-number FNo., maximum angle of view 2ω, and variable plane spacing relative to the d line. The zoom ratio is synonymous with zoom ratio and zoom magnification. The [°] in the 2ω column indicates that the unit is degrees. In Table 2, the columns labeled "Wide," "Middle," and "Tele" show the values ​​for the wide-angle end, intermediate focal length, and telephoto end, respectively.

[0143] In the table of basic lens data, an asterisk * is marked next to the surface number of an aspheric surface, and the value of the paraxial radius of curvature is described in the column for the radius of curvature of the aspheric surface. In Table 3, the row Sn shows the surface number of the aspheric surface, and the rows KA and Am show the numerical values of the aspheric coefficients for each aspheric surface. Note that m in Am is an integer of 3 or greater, and differs depending on the surface. For example, on the first surface in Example 1, m = 4, 6, 8, ··· 20. In the numerical values of aspheric coefficients in Table 3, "E±n" (n: integer) means "×10 ±n ^n". KA and Am are aspheric coefficients in the aspheric surface formula expressed by the following formula. Zd = C × h 2 / {1+(1-KA × C 2 × h 2 ) 1 / 2}^1 / 2 + ΣAm × h m where, Zd: depth of the aspheric surface (the length of the perpendicular drawn from a point on the aspheric surface at height h to the plane perpendicular to the optical axis Z to which the vertex of the aspheric surface is tangent) h: height (distance from optical axis Z to the lens surface) C: reciprocal of the paraxial radius of curvature KA, Am: aspheric coefficients and Σ in the aspheric formula represents the summation with respect to m.

[0144] In the data of each table, degrees are used as the unit of angle, and millimeters (mm) are used as the unit of length. However, since the optical system can be used even after proportional expansion or proportional reduction, other appropriate units may also be used. In addition, each table shown below describes numerical values rounded to a predetermined number of digits.

[0145]

Table 1A

[0146]

Table 1B

[0147]

Table 2

[0148] [Table 3]

[0149] Figure 14 shows the aberration diagrams for the zoom lens of Example 1 when focused on an object at infinity. In Figure 14, the upper section labeled "Wide" shows the aberrations at the wide-angle end, the middle section labeled "Middle" shows the aberrations at intermediate focal lengths, and the lower section labeled "Tele" shows the aberrations at the telephoto end. From left to right in Figure 14, the diagrams show spherical aberration, astigmatism, distortion, and chromatic aberration. In the spherical aberration diagram, the aberrations along the d, C, F, and g lines are shown as solid lines, long dashed lines, short dashed lines, and dashed lines, respectively. In the astigmatism diagram, the aberration along the d line in the sagittal direction is shown as a solid line, and the aberration along the d line in the tangential direction is shown as a short dashed line. In the distortion diagram, the aberration along the d line is shown as a solid line. In the chromatic aberration diagram, the aberrations along the C, F, and g lines are shown by long dashed lines, short dashed lines, and dashed lines, respectively. In the spherical aberration diagram, the value of the wide-open F number is shown after "FNo.=". In other aberration diagrams, the value of the maximum half-angle of view is shown after "ω=".

[0150] The symbols, meanings, methods of description, and methods of illustration for each data point in Example 1 described above are basically the same in the following examples unless otherwise specified, so redundant explanations will be omitted below.

[0151] [Example 2] Figure 15 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 2. The zoom lens of Example 2 consists of, in order 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.

[0152] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The zoom lens of Embodiment 2 has two focus groups, G1B and G1C. When focusing from an object at infinity to an object at a close distance, the G1B and G1C subgroups change their relative distances and move towards the object, while the other groups remain fixed relative to the image plane Sim.

[0153] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0154] For the zoom lens of Example 2, the basic lens data is shown in Tables 4A and 4B, the specifications and variable plane spacing are shown in Table 5, and the aberration diagrams are shown in Figure 16.

[0155] [Table 4A]

[0156] [Table 4B]

[0157] [Table 5]

[0158] [Example 3] Figure 17 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 3. The zoom lens of Example 3 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, and a final lens group GE having positive refractive power.

[0159] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The zoom lens of Embodiment 3 has two focus groups, G1B and G1C. When focusing from an object at infinity to an object at a close distance, the G1B and G1C subgroups change their relative distances and move toward the object side, while the other groups remain fixed relative to the image plane Sim.

[0160] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0161] For the zoom lens of Example 3, the basic lens data is shown in Tables 6A and 6B, the specifications and variable plane spacing are shown in Table 7, the aspherical coefficient is shown in Table 8, and the aberration diagrams are shown in Figure 18.

[0162] [Table 6A]

[0163] [Table 6B]

[0164] [Table 7]

[0165] [Table 8]

[0166] [Example 4] Figure 19 shows a cross-sectional view and movement trajectory of the configuration of the zoom lens of Example 4. The zoom lens of Example 4 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, and a final lens group GE having positive refractive power.

[0167] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The zoom lens of Embodiment 4 has two focus groups, G1B and G1C. When focusing from an object at infinity to an object at a close distance, the G1B and G1C subgroups change their relative distances and move toward the object side, while the other groups remain fixed relative to the image plane Sim.

[0168] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0169] For the zoom lens of Example 4, the basic lens data is shown in Tables 9A and 9B, the specifications and variable plane spacing are shown in Table 10, the aspherical coefficient is shown in Table 11, and the aberration diagrams are shown in Figure 20.

[0170] [Table 9A]

[0171] [Table 9B]

[0172] [Table 10]

[0173] [Table 11]

[0174] [Example 5] Figure 21 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 5. The zoom lens of Example 5 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, and a final lens group GE having positive refractive power.

[0175] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The zoom lens of Example 5 has two focus groups, G1B and G1C. When focusing from an object at infinity to an object at a close distance, the G1B and G1C subgroups change their relative distances and move toward the object side, while the other groups remain fixed relative to the image plane Sim.

[0176] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0177] For the zoom lens of Example 5, the basic lens data is shown in Tables 12A and 12B, the specifications and variable plane spacing are shown in Table 13, the aspherical coefficient is shown in Table 14, and the aberration diagrams are shown in Figure 22.

[0178] [Table 12A]

[0179] [Table 12B]

[0180] [Table 13]

[0181] [Table 14]

[0182] [Example 6] Figure 23 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 6. The zoom lens of Example 6 has a configuration in which the EX group EX is added to the zoom lens of Example 5. In the zoom lens of Example 6, the EX group EX can be inserted into and removed from the optical path. Figure 23 shows the state in which the EX group EX is inserted into the optical path between the fourth lens group G4 and the final lens group GE. The configuration of the lens groups other than the EX group EX, the movement of each group during focusing, and the behavior of each lens group during zoom variation are the same as those of the zoom lens of Example 5.

[0183] For the zoom lens of Example 6, the basic lens data is shown in Tables 15A and 15B, the specifications and variable plane spacing are shown in Table 16, the aspherical coefficient is shown in Table 17, and the aberration diagrams are shown in Figure 24.

[0184] [Table 15A]

[0185] [Table 15B]

[0186] [Table 16]

[0187] [Table 17]

[0188] [Example 7] Figure 25 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 7. The zoom lens of Example 7 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having negative refractive power, and a final lens group GE having positive refractive power.

[0189] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The focusing group consists of the G1B subgroup. When focusing from an object at infinity to a nearby object, the G1B subgroup moves towards the image side, while the other groups remain fixed relative to the image plane Sim.

[0190] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0191] For the zoom lens of Example 7, the basic lens data is shown in Tables 18A and 18B, the specifications and variable plane spacing are shown in Table 19, the aspherical coefficient is shown in Table 20, and the aberration diagrams are shown in Figure 26.

[0192] [Table 18A]

[0193] [Table 18B]

[0194] [Table 19]

[0195] [Table 20]

[0196] [Example 8] Figure 27 shows a cross-sectional view and movement trajectory of the zoom lens configuration of Example 8. The zoom lens of Example 8 consists of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, and a final lens group GE having positive refractive power.

[0197] The first lens group G1 consists of three subgroups, G1A, G1B, and G1C, arranged in order from the object side to the image side. The zoom lens of Example 8 has two focus groups, G1B and G1C. When focusing from an object at infinity to an object at a close distance, the G1B and G1C subgroups change their relative distances and move toward the object side, while the other groups remain fixed relative to the image plane Sim.

[0198] When changing magnification 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 move along the optical axis Z by changing the spacing between adjacent lens groups.

[0199] For the zoom lens of Example 8, the basic lens data is shown in Tables 21A and 21B, the specifications and variable plane spacing are shown in Table 22, the aspherical coefficient is shown in Table 23, and the aberration diagrams are shown in Figure 28.

[0200] [Table 21A]

[0201] [Table 21B]

[0202] [Table 22]

[0203] [Table 23]

[0204] [Example 9] FIG. 29 shows a cross-sectional view of the configuration of the zoom lens of Example 9 and movement trajectories thereof. The zoom lens of Example 9 comprises, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, and a final lens group GE having positive refractive power.

[0205] The first lens group G1 comprises, in order from the object side to the image side, a first A subgroup G1A, a first B subgroup G1B, and a first C subgroup G1C. A focus group consists of the first B subgroup G1B. During focusing from an infinite distance object to a close-distance object, the first B subgroup G1B moves toward the image side, and other groups are fixed with respect to the image plane Sim.

[0206] During zooming from the wide-angle end to the telephoto end, the first lens group G1 and the final lens group GE are fixed with respect to the image plane Sim, and the other lens groups move along the optical axis Z while changing the spacing between adjacent lens groups.

[0207] For the zoom lens of Example 9, basic lens data are shown in Tables 24A and 24B, specifications and variable surface spacings are shown in Table 25, and various aberration diagrams are shown in FIG. 30.

[0208] [Table 24A]

[0209] [Table 24B]

[0210] [Table 25]

[0211] Table 26 shows the corresponding values of conditional expressions (1) and (5) to (8) of the zoom lenses of Examples 1 to 9. Examples of corresponding values of conditional expressions (2) to (4) are as shown in FIG. 6. The unit of the corresponding values of conditional expression (1) in Table 26 is mm (millimeters). The values shown in Table 26 and FIG. 6 may be used as the upper limit or lower limit of the conditional expressions to set preferred ranges for the conditional expressions.

[0212] [Table 26]

[0213] Tables 27 to 29 show the values of Dexp at each focal length of the zoom lenses of Examples 1 to 9. The values shown in Tables 27 to 29 are values obtained when the zoom lens is focused on an object at infinity.

[0214] [Table 27]

[0215] [Table 28]

[0216] [Table 29]

[0217] [Modification] The technology of the present disclosure has been described above with reference to embodiments and examples, but the technology of the present disclosure is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, Abbe number, aspheric coefficient, and the like of each lens included in the zoom lens are not limited to the values shown in the above examples, and may take other values.

[0218] The zoom lens may be configured to include an image stabilization group consisting of at least one lens that moves during image blur correction. The lens device may also be configured to include an image blur detection unit that detects the position of the image stabilization group and uses the detected position to detect the state of image blur correction. In this case, it is preferable that the correction data for correcting color shading has correction values ​​set for each state of image blur correction.

[0219] In the above example, a three-plate color separation prism that separates a light beam into three in the order of blue light, red light, and green light was described as a color separation prism, but the color separation prisms of the present disclosure are not limited to the above example. In the art of the present disclosure, the colors of the light beams to be separated, the order in which each color light beam is separated, and the number of light beams to be separated may differ from the above example.

[0220] In the above description, an example was given in which the imaging device body includes a processing unit for performing color shading correction. However, in the technology of this disclosure, the lens device may be configured to include a processing unit for performing color shading correction.

[0221] The imaging device described herein is not limited to broadcast cameras, but can take various forms, including cameras for filmmaking, digital cameras, video cameras, surveillance cameras, FA (Factory Automation) cameras, and MV (Machine Vision) cameras.

[0222] The following additional information is disclosed regarding the above embodiments and examples. [Note 1] A lens device equipped with a zoom lens, The zoom lens includes a first lens group that is positioned closest to the object and fixed to the image plane when zooming, which includes a focus group that moves when focusing; a plurality of moving lens groups that move by changing the distance between adjacent lens groups when zooming; and a final lens group that is positioned closest to the image and fixed to the image plane when zooming. The aforementioned lens device is It is detachable from the main body of the imaging device which has a color separation prism. A storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens through the color separation prism with the main body of the imaging device, The system includes a communication unit that transmits the correction data to the imaging device body, The correction data has correction values ​​set for each combination of the zoom state, focus state, and aperture state of the zoom lens at a specific image height. Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the specific image height is defined as 0.49 × f × tanω. 1.5 mm < 0.49 × f × tanω < 5 mm (1) A lens device that satisfies the condition (1) represented by . [Note 2] A lens device equipped with a zoom lens, The zoom lens includes a first lens group that is positioned closest to the object and fixed to the image plane when zooming, which includes a focus group that moves when focusing; a plurality of moving lens groups that move by changing the distance between adjacent lens groups when zooming; and a final lens group that is positioned closest to the image and fixed to the image plane when zooming. The aforementioned lens device is It is detachable from the main body of the imaging device which has a color separation prism. A storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens through the color separation prism with the main body of the imaging device, The system includes a communication unit that transmits the correction data to the imaging device body, The correction data has correction values ​​set for each combination of the zoom state, focus state, and aperture state of the zoom lens. If the number of zoom states, the number of focus states, and the number of aperture states in each of the above combination groups are Nz, Nf, and Na, respectively, 0.05 ≤ Nf / (Nz × Na) ≤ 0.3 (2) 8 ≤ (Nz × Nf) / Na ≤ 256 (3) A lens device that satisfies the conditions (2) and (3) represented by . [Note 3] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. 1.5 mm < 0.49 × f × tanω < 5 mm (1) The condition (1) expressed by satisfies The lens device described in Appendix 2. [Note 4] If the number of zoom states, the number of focus states, and the number of aperture states in each of the above combination groups are Nz, Nf, and Na, respectively, 256 ≤ Nz × Nf × Na ≤ 2048 (4) The condition (4) expressed by satisfies A lens device as described in any one of the appendices 1 through 3. [Note 5] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. Of the light rays incident on the image plane of the zoom lens at the specific image height, the light ray that is incident at an angle bisector of the angle between the upper ray and the lower ray is defined as the intermediate ray. Let ft be the focal length when the zoom lens is in focus on an object at infinity at its telephoto end. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. Let Dexp be the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an object at infinity. The sign of Dexp is determined by taking the image plane as the reference, where the distance on the image side is positive and the distance on the object side is negative. The Dexp of the aforementioned zoom lens at the wide-angle end is negative. The Dexp at the telephoto end of the aforementioned zoom lens is positive. The focal length of the zoom lens when Dexp is at infinity is fw × (ft / fw). 0.6 The above and fw×(ft / fw) 0.9 Within the following range A lens device as described in any one of the appendices 1 through 4. [Note 6] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power that moves during magnification, one to three lens groups that move while changing the distance between adjacent lens groups during magnification, and the final lens group having positive refractive power. A lens device as described in any one of the appendices 1 through 5. [Note 7] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second lens group and the third lens group move while changing their relative distance from each other. A lens device as described in any one of the appendices 1 through 5. [Note 8] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second lens group, the third lens group, and the fourth lens group move by changing the distance between them and adjacent lens groups. A lens device as described in any one of the appendices 1 through 5. [Note 9] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second lens group, the third lens group, and the fourth lens group move by changing the distance between them and adjacent lens groups. A lens device as described in any one of the appendices 1 through 5. [Note 10] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. A lens device as described in any one of the appendices 1 through 5. [Note 11] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. A lens device as described in any one of the appendices 1 through 5. [Note 12] The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. A lens device as described in any one of the appendices 1 through 5. [Note 13] The EX group can be inserted into and removed from the optical path of the zoom lens, and the focal length is changed by such insertion and removal. The system includes an insertion / removal detection unit that detects the state of insertion and removal, The correction value is set for each insertion / removal state. A lens device as described in any one of the appendices 1 through 12. [Note 14] Let FNot be the maximum aperture F-number when the zoom lens is in focus on an object at infinity at its telephoto end. Let ft be the focal length when the zoom lens is in focus on an object at infinity at its telephoto end. If fw is the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end, 0.03 <FNot / (ft / fw)<0.3 (5) The condition (5) expressed by satisfies A lens device as described in any one of the appendices 1 through 13. [Note 15] Among the lens group in the aforementioned zoom lens that has negative refractive power and moves during magnification, let fn be the focal length of the lens group with the strongest negative refractive power. If the focal length of the aforementioned zoom lens when it is in focus on an object at infinity is denoted as ft, -0.4 <fn / ft<-0.02 (6) The condition (6) expressed by satisfies A lens device as described in any one of the appendices 1 through 14. [Note 16] The first lens group of the zoom lens comprises, in order from the object side to the image side, a first A subgroup having a negative refractive force that is fixed to the image plane when in focus, a first B subgroup having a positive refractive force that moves along the optical axis when in focus, and a first C subgroup whose distance from the first B subgroup changes when in focus. A lens device as described in any one of the appendices 1 through 15. [Note 17] Let Bf be the back focus of the aforementioned zoom lens at the air-equivalent distance. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. If ωw is the maximum half-angle of view when the zoom lens is in focus on an object at infinity at its wide-angle end, 4 <Bfw / (fw×tanωw)<10 (7) The condition (7) expressed by satisfies A lens device as described in any one of the appendices 1 through 16. [Note 18] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. Of the light rays incident on the image plane of the zoom lens at the specific image height, the light ray that is incident at an angle bisector of the angle between the upper ray and the lower ray is defined as the intermediate ray. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. Let Dexpw be the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an object at infinity at its wide-angle end. If an optical element that does not have refractive power is placed between the image plane and the exit pupil position of the intermediate ray, when calculating Dexpw for the optical element using the air equivalent distance, 4<|Dexpw / fw|<360 (8) The condition (8) expressed by satisfies A lens device as described in any one of the appendices 1 through 17. [Note 19] Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 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 on the image side of the image plane throughout the entire zoom range. A lens device as described in any one of the appendices 1 through 18. [Note 20] A lens device described in any one of the appendices 1 to 19, The imaging device body is provided, The imaging device body is The aforementioned color separation prism, An image sensor that captures the image formed by the zoom lens, An imaging apparatus including a processing unit that performs a process to correct the color shading of the image data based on the correction data transmitted from the lens device. [Explanation of symbols]

[0223] 1 Zoom lens 10 Lens device 12 Focus detection unit 14 Zoom detection unit 16 Aperture detection unit 20 Memory section 22 Correction data 30 Communications Department 40 Mount 50 Imaging device main unit 60-color separation prism 61 First prism member 61B Blue light transmission filter 62 Second prism member 62R Red Light Transmission Filter 63 Third prism member 63G Green Light Transmission Filter 64 First Optical Filter 65. Second Optical Filter 68 Image sensors 70 Processing Unit 80 Communications Department 90 Display section 100 Imaging device 200 Imaging device 201 Zoom Lens 218 Insertion / removal detection unit 220 Storage section 222 Correction data Area A EX EX group G1 First Lens Group G1A 1st A subgroup G1B 1B subgroup G1C 1C subgroup G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group GE Final Lens Series L incident light flux L11~L59 Lenses LB blue light lg green light LR Red Light P1 Plot P6 Plot P7 Plot P8 Plot Pexpw exit pupil position Ry1 upper ray Ry2 lower ray Ry3 mid-ray Sim image plane St aperture diaphragm Ys specific image height Z optical axis ωm Maximum half-angle ωt Maximum half-angle ωw Maximum half-angle

Claims

1. A lens device equipped with a zoom lens, The zoom lens includes a first lens group that is positioned closest to the object and fixed to the image plane when zooming, which includes a focus group that moves when focusing; a plurality of moving lens groups that move by changing the distance between adjacent lens groups when zooming; and a final lens group that is positioned closest to the image and fixed to the image plane when zooming. The aforementioned lens device is It is detachable from the main body of the imaging device which has a color separation prism. A storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens through the color separation prism with the main body of the imaging device, The system includes a communication unit that transmits the correction data to the main body of the imaging device, The correction data has correction values ​​set for each combination of the zoom state, focus state, and aperture state of the zoom lens at a specific image height. If the focal length and maximum half-angle of view of the zoom lens in each zoom state are f and ω, respectively, and the unit of f is mm, then the specific image height is defined as 0.49 × f × tanω. 1.5mm<0.49×f×tanω<5mm (1) A lens device that satisfies the condition (1) represented by .

2. A lens device equipped with a zoom lens, The zoom lens includes a first lens group that is positioned closest to the object and fixed to the image plane when zooming, which includes a focus group that moves when focusing; a plurality of moving lens groups that move by changing the distance between adjacent lens groups when zooming; and a final lens group that is positioned closest to the image and fixed to the image plane when zooming. The aforementioned lens device is It is detachable from the main body of the imaging device which has a color separation prism. A storage unit that stores correction data for correcting color shading of image data obtained by imaging the image formed by the zoom lens through the color separation prism with the main body of the imaging device, The system includes a communication unit that transmits the correction data to the imaging device body, The correction data has correction values ​​set for each combination of the zoom state, focus state, and aperture state of the zoom lens. If the number of zoom states, the number of focus states, and the number of aperture states in each of the above combination groups are Nz, Nf, and Na, respectively, 0.05 ≤ Nf / (Nz × Na) ≤ 0.3 (2) 8 ≤ (Nz × Nf) / Na ≤ 256 (3) A lens device that satisfies the conditions (2) and (3) represented by .

3. Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. 1.5mm<0.49×f×tanω<5mm (1) The condition (1) expressed by satisfies The lens device according to claim 2.

4. If the number of zoom states, the number of focus states, and the number of aperture states in each of the above combination groups are Nz, Nf, and Na, respectively, 256 ≤ Nz × Nf × Na ≤ 2048 (4) The condition (4) expressed by satisfies The lens device according to claim 1 or claim 2.

5. Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. Of the light rays incident on the image plane of the zoom lens at the specific image height, the light ray that is incident at an angle bisector of the angle between the upper ray and the lower ray is defined as the intermediate ray. Let ft be the focal length when the zoom lens is in focus on an object at infinity at its telephoto end. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. Denoted as Deexp, the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an object at infinity, The sign of DeExp is determined by taking the image plane as the reference, with the distance on the image side being positive and the distance on the object side being negative. The DeExp at the wide-angle end of the aforementioned zoom lens is negative. The DeExp at the telephoto end of the aforementioned zoom lens is positive. The focal length of the zoom lens when Dexp is at infinity is fw × (ft / fw) ０．６ The above and fw × (ft / fw) ０．９ Within the following range The lens device according to claim 1 or claim 2.

6. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power that moves during magnification, one to three lens groups that move while changing the distance between adjacent lens groups during magnification, and the final lens group having positive refractive power. The lens device according to claim 1 or claim 2.

7. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second lens group and the third lens group move while changing their relative distance from each other. The lens device according to claim 1 or claim 2.

8. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second lens group, the third lens group, and the fourth lens group move by changing the distance between them and adjacent lens groups. The lens device according to claim 1 or claim 2.

9. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second lens group, the third lens group, and the fourth lens group move by changing the distance between them and adjacent lens groups. The lens device according to claim 1 or claim 2.

10. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. The lens device according to claim 1 or claim 2.

11. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. The lens device according to claim 1 or claim 2.

12. The zoom lens comprises, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having negative refractive power, and the final lens group having positive refractive power. During magnification, the second, third, fourth, and fifth lens groups move by changing the distance between them and adjacent lens groups. The lens device according to claim 1 or claim 2.

13. The EX group can be inserted into and removed from the optical path of the aforementioned zoom lens, and the focal length is changed by such insertion and removal. The system includes an insertion / removal detection unit that detects the state of insertion and removal, The correction value is set for each insertion / removal state. The lens device according to claim 1 or claim 2.

14. Let FNot be the maximum aperture F-number when the zoom lens is in focus on an object at infinity at its telephoto end. Let ft be the focal length when the zoom lens is in focus on an object at infinity at its telephoto end. If fw is the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end, 0.03<FNot / (ft / fw)<0.3 (5) The condition (5) expressed by satisfies The lens device according to claim 6.

15. Among the lens group in the aforementioned zoom lens that has negative refractive power and moves during magnification, let fn be the focal length of the lens group with the strongest negative refractive power. If the focal length of the aforementioned zoom lens when it is in focus on an object at infinity is denoted as ft, -0.4<fn / ft<-0.02 (6) The condition (6) expressed by satisfies The lens device according to claim 6.

16. The first lens group of the zoom lens comprises, in order from the object side to the image side, a first A subgroup having a negative refractive force that is fixed to the image plane when focusing, a first B subgroup having a positive refractive force that moves along the optical axis when focusing, and a first C subgroup whose distance from the first B subgroup changes when focusing. The lens device according to claim 6.

17. Let Bf be the back focus of the aforementioned zoom lens at the air-equivalent distance. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. If ωw is the maximum half-angle of view when the zoom lens is in focus on an object at infinity at its wide-angle end, 4<Bfw / (fw×tanωw)<10 (7) The condition (7) expressed by satisfies The lens device according to claim 1 or claim 2.

18. Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 0.49 × f × tanω. Of the light rays incident on the image plane of the zoom lens at the specific image height, the light ray that is incident at an angle bisector of the angle between the upper ray and the lower ray is defined as the intermediate ray. Let fw be the focal length when the zoom lens is in focus on an object at infinity at its wide-angle end. Denoted as Deexpw, the distance from the image plane to the exit pupil position of the intermediate ray when the zoom lens is focused on an object at infinity at its wide-angle end, If an optical element that does not have refractive power is placed between the image plane and the exit pupil position of the intermediate ray, when calculating DeExpw for the optical element using the air equivalent distance, 4<|Dexpw / fw|<360 (8) The condition (8) expressed by satisfies The lens device according to claim 1 or claim 2.

19. Let f and ω be the focal length and maximum half-angle of view of the zoom lens in each zoom state, respectively, and let f be in mm. Then the correction value is the value at a specific image height defined as 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 on the image side of the image plane throughout the entire zoom range. The lens device according to claim 1 or claim 2.

20. A lens device according to claim 1 or claim 2, The imaging device body is provided, The imaging device body is The aforementioned color separation prism, An image sensor that captures the image formed by the zoom lens, An imaging apparatus including a processing unit that performs a process to correct the color shading of the image data based on the correction data transmitted from the lens device.

Images