Lens device and imaging device having the same, imaging system

Abstract

To provide a lens device that offers a wide field of view while appropriately correcting lens breathing. [Solution] A lens device that is detachable from an imaging device having an image sensor, and whose half-angle of view corresponding to the maximum image height at infinity focus at the wide-angle end exceeds 90°, comprising a first communication means for communicating with the imaging device, wherein the first communication means transmits to the imaging device information regarding the region of the image formed by the lens device on the image sensor.

Description

Technical Field

[0001] The present invention relates to a lens device, and is suitable for an imaging device using an imaging element such as a digital still camera, a video camera, a broadcast camera, a surveillance camera, an in-vehicle camera, or an imaging device such as a camera using a silver halide photographic film.

Background Art

[0002] A lens device used in an imaging device is required to have good optical characteristics while having a wide angle of view. Patent Document 1 discloses a negative lead type lens device in which a lens group having a negative refractive power on the object side is arranged as a wide-angle lens device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a lens device, it is required to correct a change in the angle of view due to focusing, that is, bleeding. In particular, in an imaging device using a wide-angle lens device, since the area actually used for imaging is limited with respect to the entire area on the imaging surface of the imaging element, it is necessary to perform appropriate bleeding correction.

Means for Solving the Problems

[0005] A lens device according to one aspect of the present invention is a lens device that is detachable from an imaging device having an imaging element, and has a half angle of view corresponding to the maximum image height at infinity focus at the wide-angle end exceeding 90°, and includes a first communication means for communicating with the imaging device, and the first communication means transmits information regarding the area of an image formed by the lens device on the imaging element to the imaging device. [Effects of the Invention]

[0006] This allows us to provide a lens device that offers a wide field of view while also being able to properly correct for lens breathing. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the lens device of Example 1 [Figure 2] Aberration diagram of the lens device in Example 1 [Figure 3] Cross-sectional view of the lens device of Example 2 [Figure 4] Aberration diagram of the lens device in Example 2 [Figure 5] Cross-sectional view of the lens device of Example 3 [Figure 6] Aberration diagram of the lens device in Example 3 [Figure 7] Cross-sectional view of the lens device of Example 4 [Figure 8] Aberration diagram of the lens device in Example 4 [Figure 9] Cross-sectional view of the lens device of Example 5 [Figure 10] Aberration diagram of the lens device in Example 5 [Figure 11] Cross-sectional view of the lens device of Example 6 [Figure 12] Aberration diagram of the lens device of Example 6 [Figure 13] Schematic diagram of the electrical configuration of the lens apparatus in Examples 1 to 6 [Figure 14] Schematic diagram of the electrical configuration of the imaging device [Figure 15] Schematic diagram of the light-shielding area in the imaging device. [Figure 16] Schematic diagram of the imaging device [Figure 17] Flowchart of the imaging device [Figure 18] Diagram and flowchart of the first correction method [Figure 19] Diagram and flowchart of the second correction method [Figure 20] Diagram and flowchart of the third correction method [Figure 21] Diagram and flowchart of the fourth correction method

Mode for Carrying Out the Invention

[0008] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the drawings. Note that each drawing may be drawn at a scale different from the actual one for convenience. Also, in each drawing, the same members are denoted by the same reference numerals, and redundant explanations are omitted.

[0009] Figs. 1, 3, 5, 7, 9, and 11 are cross-sectional views of the lens device L0 at the wide-angle end of Examples 1 to 6 in a state focused at infinity. The lens device L0 of each embodiment is used in an imaging device such as a digital video camera, a digital still camera, a broadcast camera, a silver halide film camera, a surveillance camera, or an optical device including an interchangeable lens. In each cross-sectional view, the left side is the object side and the right side is the image side.

[0010] The lens device L0 of each embodiment is composed of a plurality of lens groups. Note that the lens group in this specification is a collection of one or more lenses that move integrally during zooming. In the lens device L0 of each embodiment, the distance between adjacent lens groups changes during zooming from the wide-angle end to the telephoto end.

[0011] In each cross-sectional view, Li represents the i-th (i is a natural number) lens group counted from the object side among the lens groups included in the lens device L0. Also, LR is the rear group and includes all the lenses and lens groups arranged on the image side of the first lens group L1.

[0012] In each cross-sectional view, SP is the aperture diaphragm. In each cross-sectional view, IP is the image plane, and when the lens device L0 of each embodiment is used as the photographic optical system of a digital still camera or digital video camera, the image plane of a solid-state image sensor such as a CCD sensor or a photoelectric conversion element such as a CMOS sensor is arranged on the image plane IP. Furthermore, when the lens device L0 of each embodiment is used as the photographic optical system of a silver halide film camera, a photosensitive surface corresponding to the film plane is arranged on the image plane IP.

[0013] The solid arrows shown in each lens cross-sectional diagram represent a simplified representation of the movement trajectory of each lens group when zooming from the wide-angle end to the telephoto end. In this specification, the wide-angle end and telephoto end refer to the zoom positions when each lens group is located at the ends of the range in which it can move along the optical axis. The dashed arrows shown in each lens cross-sectional diagram represent a simplified representation of the movement trajectory of the focus group LF when focusing from infinity to close range, as it moves relative to the image plane.

[0014] The lens apparatus L0 of each embodiment consists of a first lens group L1 with negative refractive power, arranged sequentially from the object side to the image side, and a rear group LR including one or more lens groups. The rear group LR includes all lens groups positioned closer to the image side than the first lens group L1. In the lens apparatus L0 of each embodiment, an optical element with substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be placed between the lens positioned closest to the image and the imaging plane.

[0015] Figures 2, 4, 6, 8, 10, and 12 are aberration diagrams of the lens apparatus L0 of Examples 1 to 6. Each aberration diagram represents the aberration of each example when focused at infinity, with (A) being at the wide-angle end, (B) at the intermediate zoom position, and (C) at the telephoto end.

[0016] In the spherical aberration diagram, Fno is the F-number, and the solid line shows the amount of spherical aberration for the d-line (wavelength 587.6 nm) and the dashed g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS shows the amount of astigmatism at the sagittal image plane, and ΔM shows the amount of astigmatism at the meridional image plane. In the distortion diagram, the solid line shows the amount of distortion for the d-line. In the chromatic aberration diagram, the dashed line shows the amount of chromatic aberration at the g-line. In each aberration diagram, ω is the half-angle of view (°), which is the angle of view calculated paraxially.

[0017] In the lens apparatus L0 of each embodiment, the projection method of Embodiments 1 to 3 is an equi-angle projection method expressed by the equation Y = f·θ. The projection method of Embodiments 4 to 6 is an equi-solid angle projection method expressed by the equation Y = 2·f·sin(θ / 2). Here, f represents the focal length of the entire lens apparatus L0 system, and θ represents the angle of incidence of the light ray. Note that the projection method in the lens apparatus of each embodiment is not limited to equi-angle projection or equi-solid angle projection, and other projection methods may be used.

[0018] Next, we will describe the electrical configuration common to the lens device 200 in each embodiment.

[0019] Figure 13 is a schematic diagram of the characteristic electrical configuration of the lens apparatus 200 in each embodiment.

[0020] The lens device 200 includes a lens substrate 201 and a lens mount 202. The lens mount 202 can be attached to an imaging device, which will be described later. The lens device 200 has the same configuration as the lens device L0 described above.

[0021] The lens substrate 201 includes a lens CPU 203, a focal position detection means 204, and a zoom position detection means 205. The focal position detection means 204 can detect the current focal position (hereinafter referred to as the actual focal length) of the lens device 200. The zoom position detection means 205 can detect the current zoom position of the lens device 200.

[0022] The lens CPU 203 includes a lens communication means 206 and a storage means 207.

[0023] The lens communication means 206 controls communication between the lens device 200 and an external device. In the embodiments described herein, the external device is an imaging device attached to the lens device 200, but is not limited to this; an image processing device and other devices also qualify as external devices. In this specification, the lens communication means 206 corresponds to the first communication means.

[0024] The storage means 207 stores lens-specific optical information. In this disclosure, lens-specific optical information refers to first optical information relating to the current zoom position of the lens device 200, second optical information relating to the variation in actual focal length, and third optical information relating to the light-shielding region. However, it is not limited to these, and other optical information may also be stored.

[0025] Here, the second optical information, which is information regarding the variation in actual focal length, is information for obtaining the rate of change of the actual focal length with respect to the maximum focal length that can be taken within the range in which the focus group LF of the lens device 200 can be driven (hereinafter referred to as the maximum actual focal length). At this time, the rate of variation of the actual focal length is Actual focal length variation rate = Actual focal length / Maximum actual focal length The calculation is performed using the following formula. The second optical information is defined for each focus position and stored in the storage means 207 as an actual focal length information table.

[0026] Furthermore, the third type of optical information, information regarding the light-shielding region, refers to information regarding the region of the image sensor of the lens device 200 where an optical image is not formed, i.e., the region that is shielded from light and not used for imaging. Figure 15 is a conceptual diagram illustrating the light-shielding region. In Figure 15, the rectangles drawn with solid lines represent the image-capable region of the image sensor, the circles drawn with dashed lines represent the image circle region, and the gray shaded areas represent the light-shielding region. Specifically, the light-shielding region is defined by information regarding the image region formed by the lens device 200 on the image sensor, i.e., the image circle, and refers to the region of the image-capable region of the image sensor that does not include the image circle. The light-shielding region is defined for each focus position and stored as a light-shielding region table by the storage means 207.

[0027] The lens CPU 203 transmits the information detected by the focus position detection means 204 and the zoom position detection means 205, as well as the information stored in the storage means 207, to the imaging device via the lens communication means 206.

[0028] Figure 14 is a schematic diagram of the electrical configuration of the imaging device in this embodiment.

[0029] The imaging device 300 includes a camera substrate 301, a camera mount 302, and an imaging means 303. The camera mount 302 is capable of mounting a lens device, and as shown in the figure, the lens device 200 is mounted on the imaging device 300 via a lens mount 202.

[0030] The camera substrate 301 includes an imaging means 303 and a camera CPU 304.

[0031] The imaging means 303 captures an image by converting the optical image formed by the lens device 200 into an optical image.

[0032] The camera CPU 304 includes a camera communication means 305, an image generation means 306, and a correction means 307.

[0033] The camera communication means 305 controls communication between the lens device 200 and the imaging device 300 via the camera mount 302. In this specification, the camera communication means 305 corresponds to a second communication means.

[0034] The image generation means 306 generates an image based on the image signal that has been photoelectrically converted by the imaging means 303.

[0035] The correction means 307 corrects the image generated by the image generation means 306.

[0036] The camera CPU 304 corrects the image using the correction means 307 based on the information received from the lens device 200 via the camera communication means 305.

[0037] Next, we will describe the characteristic configuration of the lens device L0 in each embodiment.

[0038] When the half-angle of view at infinity focus at the wide-angle end of the lens device L0 in each embodiment is denoted as ωw(°), satisfying the condition ωw > 90 allows for obtaining the wide angle of view necessary for a fisheye lens device or an ultra-wide-angle lens device. Furthermore, to obtain a sufficiently wide angle of view for a fisheye lens device or an ultra-wide-angle lens device, it is more preferable to satisfy the condition ωw > 92. It is even more preferable to satisfy the condition ωw > 94.

[0039] In the imaging device 300 to which the lens device L0 of each embodiment is applied, the correction means 307 performs cropping correction on a portion of the captured image in order to suppress breathing. At that time, the correction means 307 performs cropping correction after excluding the light-shielding region based on third optical information regarding the light-shielding region at the current zoom position. This shortens the correction process by eliminating unnecessary processing in the electrical correction of breathing, and makes it possible to perform appropriate breathing correction.

[0040] The specific correction method of the correction means 307 will be described later.

[0041] With the above configuration, a lens system is obtained that offers a wide angle of view while suppressing focusing-induced breathing.

[0042] Next, we will describe the conditions that are preferable for the lens device L0 of each embodiment to satisfy.

[0043] In the lens apparatus L0 of each embodiment, it is preferable that the focusing group LF is included in the rear group LR, making it a so-called rear-focus type. This prevents the overall length of the lens from changing during focusing, thus suppressing focusing-induced breathing.

[0044] The lens device L0 of each embodiment preferably satisfies at least one of the following conditional equations (1) to (12). However, in each conditional equation, the numerical values ​​are expressed as follows.

[0045] Let fL1 be the focal length of the first lens group L1, and fL2 be the focal length of the second lens group L2.

[0046] Let fw be the focal length of lens device L0 at the wide-angle end.

[0047] Let fG1 be the focal length of lens G1, which is positioned closest to the object in the first lens group L1, and fG2 be the focal length of lens G2, which is positioned adjacent to lens G1 on the image side.

[0048] Let the focal length of the LF group be fLF.

[0049] Let fLRw be the focal length of the rear group LR at the wide-angle end of the lens device L0.

[0050] Let Skw be the back focus of lens device L0 at the wide-angle end.

[0051] DSPw is the distance along the optical axis from the aperture diaphragm SP of the lens device L0 at the wide-angle end to the lens surface closest to the image.

[0052] Let ndG1 be the refractive index of the material of lens G1, the lens closest to the object in the first lens group L1, with respect to the d line.

[0053] In the first lens group L1, of the lens G1 closest to the object, let R1 be the radius of curvature of the object-side lens surface and R2 be the radius of curvature of the image-side lens surface.

[0054] Let Yta be the maximum image height that can be captured at the telephoto end of the lens device L0, and Ywa be the maximum image height that can be captured at the wide-angle end.

[0055] -3.0 <fL1 / fw<-1.7 (1) -5.0 < |fL2| / fL1 < -1.1 (2) 1.4 <fG1 / fL1<3.0 (3) 0.40 <fG1 / fG2<1.60 (4) 3.5 <fLF / fw<15.0 (5) -4.1 <fLF / fL1<-1.8 (6) -1.30 <fL1 / fLRw<-0.55 (7) 2.0 <Skw / fw<6.0 (8) 0.40 <DSPw / Skw<1.00 (9) 1.65 <ndG1<2.20 (10) 1.3 < (R1 + R2) / (R1 - R2) < 3.0 (11) 1.5 <Yta / Ywa<3.0 (12)

[0056] Here, we will explain the technical meaning of the aforementioned conditional expressions (1) through (12).

[0057] Condition (1) defines the ratio of the focal length fL1 of the first lens group L1 to the focal length fw of the lens device L0 at the wide-angle end. By satisfying condition (1), the focal length fL1 of the first lens group L1 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fL1 of the first lens group L1 becomes too long, falling below the lower limit of condition (1), the first lens group L1 becomes large, making it difficult to miniaturize the lens device L0. If the focal length fL1 of the first lens group L1 becomes too short, exceeding the upper limit of condition (1), the image height change due to coma aberration becomes large, making it difficult to correct field curvature and astigmatism.

[0058] Condition (2) specifies the ratio of the focal length fL2 of the second lens group L2 to the focal length fL1 of the first lens group L1. By satisfying condition (2), the focal lengths fL1 of the first lens group L1 and fL2 of the second lens group L2 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fL1 of the first lens group L1 becomes too short, falling below the lower limit of condition (2), the image height change due to off-axis coma aberration becomes large, making it difficult to correct field curvature and astigmatism. If the focal length fL1 of the first lens group L1 becomes too long, exceeding the upper limit of condition (2), the first lens group L1 becomes large, making it difficult to miniaturize the lens device L0.

[0059] Condition (3) specifies the ratio of the focal length fG1 of the lens G1 closest to the object in the first lens group L1 to the focal length fL1 of the first lens group L1. By satisfying condition (3), the focal length fG1 of lens G1 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fG1 of lens G1 becomes too short, falling below the lower limit of condition (3), it becomes difficult to correct field curvature and distortion. If the focal length fG1 of lens G1 becomes too long, exceeding the upper limit of condition (3), the first lens group L1 becomes larger, making it difficult to miniaturize the lens device L0.

[0060] Conditional equation (4) specifies the ratio of the focal length fG1 of the lens G1 closest to the object in the first lens group L1 to the focal length fG2 of the lens G2 positioned adjacent to the image side of lens G1. Two negative lenses are arranged in order from the object side to achieve a wide-angle view. If the focal length fG1 of lens G1 becomes too short, falling below the lower limit of conditional equation (4), it becomes difficult to correct field curvature and distortion. If the focal length fG1 of lens G1 becomes too long, exceeding the upper limit of conditional equation (4), lens G1 and the first lens group L1 become large, making it difficult to miniaturize the lens device L0.

[0061] Conditional equation (5) defines the ratio of the focal length fLF of the focusing group LF to the focal length fw of the lens device L0 at the wide-angle end. If the focal length fLF of the focusing group LF becomes too short, falling below the lower limit of conditional equation (5), it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration associated with focusing. If the focal length fLF of the focusing group LF becomes too long, exceeding the upper limit of conditional equation (5), the amount of movement associated with focusing becomes large, making it difficult to miniaturize the lens device L0.

[0062] Condition (6) specifies the ratio of the focal length fLF of the focusing group LF to the focal length fL1 of the first lens group L1. If the focal length fLF of the focusing group LF becomes too long, below the lower limit of condition (6), the amount of movement required for focusing becomes long, making it difficult to miniaturize the optical system. If the focal length fLF of the focusing group LF becomes too short, above the upper limit of condition (6), it becomes difficult to suppress fluctuations in various aberrations, including spherical aberration, that occur during focusing.

[0063] Condition (7) specifies the ratio of the focal length fL1 of the first lens group L1 to the focal length fLRw of the rear group LR at the wide-angle end. If the focal length fL1 of the first lens group L1 becomes too long, falling below the lower limit of condition (7), the convergence effect in the rear group LR becomes large, causing strong lateral chromatic aberration and axial chromatic aberration, thus degrading optical performance. If the focal length fL1 of the first lens group L1 becomes too short, exceeding the upper limit of condition (7), it becomes difficult to correct spherical aberration and coma aberration in the rear group LR.

[0064] Conditional equation (8) defines the ratio of the back focus Skw at the wide-angle end to the focal length fw of the lens device L0 at the wide-angle end. If the back focus Skw becomes too short, falling below the lower limit of conditional equation (8), it becomes difficult to place optical elements such as a low-pass filter near the image sensor that converts the optical image formed by this lens device L0 into photoelectric form. If the back focus Skw becomes too long, exceeding the upper limit of conditional equation (8), the total optical length of the lens device L0 at the wide-angle end becomes long, making miniaturization difficult.

[0065] Conditional equation (9) defines the ratio of the distance DSPw on the optical axis from the aperture diaphragm SP to the image-side lens surface at the wide-angle end to the back focus Skw at the wide-angle end. If the distance DSPw on the optical axis from the aperture diaphragm SP to the image-side lens surface falls below the lower limit of conditional equation (9) and becomes too short, it becomes difficult to position the focus group LF. If the back focus Skw exceeds the upper limit of conditional equation (9) and becomes too short, the overall optical length of the lens device L0 at the wide-angle end becomes long, making miniaturization difficult.

[0066] Condition (10) defines the refractive index ndG1 of the material of lens G1, which is closest to the object in the first lens group L1, with respect to the d line. By satisfying condition (10), the refractive index of the material of lens G1 can be set to an appropriate range, thereby enabling good correction of chromatic aberration.

[0067] If the refractive index ndG1 of the material of the lens G1 closest to the object becomes too small, below the lower limit of condition (10), it becomes necessary to weaken the refractive power of the negative lens to correct the field curvature, which increases the back focus and makes it difficult to miniaturize the lens device L0. If the refractive index ndG1 of the material of the lens G1 closest to the object becomes too large, it becomes necessary to select a highly dispersed material with a small Abbe number, making it difficult to adequately correct distortion and chromatic aberration.

[0068] Condition (11) defines the shape of the object-side lens G1 in the first lens group L1. R1 is the radius of curvature of the object-side lens surface of the object-side lens G1, and R2 is the radius of curvature of the image-side lens surface of the object-side lens G1. By satisfying condition (11), if the value falls below the lower limit of condition (11), the refractive power of the object-side lens G1 becomes too strong, making it difficult to obtain high optical performance. If the value exceeds the upper limit of condition (11), the refractive power of the object-side lens G1 becomes too weak, making it difficult to obtain a wide field of view.

[0069] Conditional equation (12) defines the ratio of the maximum image height Yta at the telephoto end to the maximum image height Ywa at the wide-angle end. The maximum image height is the distance between the optical axis and the image point where the peripheral illumination is 15% among the image points that can be photographed. If the maximum image height at the telephoto end becomes too small, falling below the lower limit of conditional equation (12), it becomes difficult to make the lens device L0 a wide-angle lens device that includes everything from circular fisheye to diagonal fisheye.

[0070] If the maximum image height at the telephoto end becomes too large, exceeding the upper limit of condition (12), the amount of movement of each lens group or the refractive power of each lens group during zooming becomes large, making it difficult to suppress aberrations during zooming.

[0071] Furthermore, it is preferable that the numerical ranges of conditional expressions (1) to (12) be the numerical ranges of the following conditional expressions (1a) to (12a). -2.6 <fL1 / fw<-1.9 (1a) -3.6 < |fL2| / fL1 < -1.6 (2a) 1.6 <fG1 / fL1<2.7 (3a) 0.47 <fG1 / fG2<1.30 (4a) 4.4 <fLF / fw<10.0 (5a) -3.9 <fLF / fL1<-2.1 (6a) -1.20 <fL1 / fLRw<-0.60 (7a) 4.0 <Skw / fw<5.3 (8a) 0.50 <DSPw / Skw<0.81 (9a) 1.66 <ndG1<1.96 (10a) 1.5 < (R1 + R2) / (R1 - R2) < 2.7 (11a) 1.8 <Yta / Ywa<2.3 (12a)

[0072] Furthermore, it is even more preferable that the numerical ranges of conditional expressions (1) to (12) be the numerical ranges of the following conditional expressions (1b) to (12b). -2.5 <fL1 / fw<-2.0 (1b) -3.4 < |fL2| / fL1 < -1.7 (2b) 1.7 <fG1 / fL1<2.6 (3b) 0.48 <fG1 / fG2<1.20 (4b) 4.6 <fLF / fw<8.0 (5b) -3.7 <fLF / fL1<-2.2 (6b) -1.10 <fL1 / fLRw<-0.63 (7b) 4.3 <Skw / fw<4.9 (8b) 0.53 <DSPw / Skw<0.79 (9b) 1.71 <ndG1<1.91 (10b) 1.7 < (R1 + R2) / (R1 - R2) < 2.5 (11b) 1.9 <Yta / Ywa<2.1 (12b)

[0073] Next, we will describe the detailed configuration of the lens device L0 according to Examples 1 to 6. Note that in each example of the lens device L0, we will omit explanations of overlapping configurations and mainly describe the differences from Example 1.

[0074] [Example 1] Figure 1 shows a cross-sectional view of the lens device L0 of Example 1. The lens device L0 of Example 1 consists of a first lens group L1 and a rear group LR. In the lens device L0 of Example 1, the rear group LR consists of a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group L1 remains stationary relative to the image plane, while the second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5 move toward the object. The focusing group LF is the fourth lens group L4.

[0075] In the lens apparatus L0 of Example 1, the first lens group L1 is composed of two negative lenses. The second lens group L2 is composed of one negative lens, a cemented lens consisting of a positive lens and a negative lens, and another cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side. The third lens group L3 is composed of a cemented lens consisting of two positive and negative lenses, an aperture diaphragm, and one positive lens, arranged in order from the object side. The fourth lens group L4 is composed of a negative lens and a positive lens, arranged in order from the object side. The fifth lens L5 is composed of two cemented lenses consisting of a negative lens and a positive lens. By having three cemented lenses in the optical system, the correction effect of axial chromatic aberration can be further enhanced.

[0076] In the lens apparatus L0 of Example 1, the focusing group LF is the fourth lens group L4, so the 4-group lens barrel 114 is a holding member for the focusing group.

[0077] [Example 2] Figure 3 shows a cross-sectional view of the lens apparatus L0 of Example 2. In the lens apparatus L0 of Example 2, the third lens group L3 is composed of one positive lens, a cemented lens consisting of a negative lens and a positive lens, an aperture diaphragm, and one positive lens, arranged in order from the object side.

[0078] [Example 3] Figure 5 shows a cross-sectional view of the lens device L0 of Example 3. In the lens device L0 of Example 3, the second lens group L2 is composed of a cemented lens consisting of a positive lens and a negative lens, one negative lens, and a cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side. The third lens group L3 is composed of one positive lens, a cemented lens consisting of a positive lens and a negative lens, one positive lens, and an aperture diaphragm, arranged in order from the object side.

[0079] [Example 4] Figure 7 shows a cross-sectional view of the lens device L0 of Example 4. In the lens device L0 of Example 4, the second lens group L2 consists of a positive lens, a negative lens, a negative lens, and a positive lens, arranged in order from the object side. The third lens group L3 consists of a cemented lens consisting of a positive lens and a negative lens, one positive lens, a cemented lens consisting of a negative lens and a positive lens, and an aperture diaphragm, arranged in order from the object side. The fourth lens group L4 consists of a positive lens and a negative lens, arranged in order from the object side. The fifth lens group L5 consists of a negative lens and a positive lens, arranged in order from the object side.

[0080] [Example 5] Figure 9 shows a cross-sectional view of the lens device L0 of Example 5. The lens device L0 of Example 5 consists of a first lens group L1 and a rear group LR. In the lens device L0 of Example 5, the rear group LR consists of a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group L1 is stationary relative to the image plane, while the second lens group L2, third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 move toward the object. The focusing group LF is the fifth lens group L5.

[0081] In the lens apparatus L0 of Example 5, the second lens group L2 consists of a positive lens and a negative lens arranged in order from the object side. The third lens group L3 consists of a cemented lens consisting of a positive lens and a negative lens. The fourth lens group L4 consists of two cemented lenses consisting of a negative lens and a positive lens, arranged in order from the object side, and an aperture diaphragm. The fifth lens group L5 consists of one positive lens. The sixth lens group L6 consists of a negative lens, a positive lens, and a cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side.

[0082] [Example 6] Figure 11 shows a cross-sectional view of the lens device L0 of Example 6. In the lens device L0 of Example 6, the second lens group L2 consists of a cemented lens made up of a negative lens and a positive lens, and one negative lens. The third lens group L3 consists of a cemented lens made up of a positive lens and a negative lens. The fourth lens group L4 consists of a cemented lens made up of a positive lens, a negative lens, and a positive lens, and an aperture diaphragm. The fifth lens group L5 consists of a positive lens and a negative lens arranged in order from the object side. The sixth lens group L6 consists of a positive lens and a cemented lens made up of a negative lens and a positive lens, arranged in order from the object side. By having three cemented lenses in the optical system, the correction effect of axial chromatic aberration can be further enhanced.

[0083] Next, we will describe the configurations that are preferable to satisfy in the lens device L0 of each embodiment.

[0084] In the lens device L0 of each embodiment, it is preferable that the lens G1 closest to the object among the lenses included in the first lens group L1 is fixed to the image plane during zooming. This is preferable because the overall optical length of the lens device L0 does not change during zooming, thereby improving the robustness of the lens device L0.

[0085] In the lens device L0 of each embodiment, it is preferable that the first lens group L1 has two or more negative lenses in order from the object side. Furthermore, it is preferable that the lens G1 closest to the object is a convex meniscus lens on the object side, and that the vertex of the object-side surface of the lens G1 closest to the object is located closer to the object than the first lens barrel 111. This makes it easier to widen the angle of view of the lens device L0.

[0086] In the lens device L0 of each embodiment, it is preferable to make the object-side lens surface and the image-side lens surface of the lens G1 positioned closest to the object a meniscus shape with a convex surface on the object side, as this allows for easier manufacturing of the lens device L0 while satisfying the required optical performance.

[0087] In the lens device L0 of each embodiment, it is preferable that the first lens group L1 is composed of two negative lenses. Furthermore, in the lens device L0 of each embodiment, it is preferable to make all the lenses included in the first lens group L1 spherical lenses, as this makes the manufacturing of the lens device L0 even easier.

[0088] In the lens device L0 of each embodiment, it is preferable to configure the focus group LF with two or fewer lenses and to position it on the image side of the aperture diaphragm SP, as this facilitates miniaturization of the focus group LF and speeds up focusing.

[0089] In the lens apparatus L0 of each embodiment, it is more preferable to configure the rear group LR with three or more lens groups, as this makes it possible to achieve a sufficient magnification ratio.

[0090] The lens device L0 in each embodiment may include distortion correction data for correcting distortion aberration. This allows distortion aberration occurring in the lens optical system to be corrected by the lens device L0. In this case, the lens device L0 includes storage means for storing distortion correction data.

[0091] Next, the numerical examples 1 to 6 corresponding to each of the examples 1 to 6 are shown below. In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the distance on the optical axis between the m-th surface and the (m+1)-th surface. Here, m is the number of the surface counted from the light incident side. Also, nd represents the refractive index of the material of each optical component with respect to the d line, and νd represents the Abbe number of the material of the optical component. Note that the Abbe number νd of a certain material is given by Nd, NF, and NC, respectively, when the refractive indices at the Fraunhofer lines d line (587.6 nm), F line (486.1 nm), and C line (656.3 nm) are Nd, NF, and NC. νd = (Nd-1) / (NF-NC) It is represented as follows.

[0092] Furthermore, in each numerical example, d, focal length (mm), F-number, and half-angle of view (°) are all values ​​when the lens device L0 of each example is focused on an object at infinity. Back focus is the distance along the optical axis from the image-side lens surface to the paraxial image plane of the lens device L0, expressed in terms of air equivalent length. Total lens length is the distance along the optical axis from the object-side lens surface to the image-side lens surface of the lens device L0, plus the back focus. Note that the lens group in each numerical example includes not only cases composed of multiple lenses, but also cases composed of a single lens.

[0093] Furthermore, if the optical surface is aspherical, the sign * is added to the right of the surface number. The aspherical shape is expressed as follows, where X is the displacement from the surface vertex in the direction of the optical axis, h is the height from the optical axis perpendicular to the optical axis, R is the radius of paraxial curvature, K is the cone constant, and A4, A6, A8, A10, A12 are the aspherical coefficients of each order. X=(h2 / R) / [1+[1-(1+K)(h / R)2]1 / 2]+A4×h4+A6×h6+A8×h8+A10×h10+A12×h12+A14×h14

[0094] Note that "e±XX" in each aspherical coefficient represents "×10±XX".

[0095] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd 1 48.932 2.00 1.85150 40.8 2 20.284 16.25 3 557.363 1.10 1.80400 46.5 4 28.772 (variable) 5 34.855 0.90 1.85896 22.7 6 17.068 0.10 1.53344 52.7 7* 17.589 4.70 8 50.857 6.99 1.83400 37.2 9 -20.635 1.05 1.49700 81.7 10 22.129 4.34 11 -16.265 0.80 1.49700 81.7 12 21.161 3.64 1.66565 35.6 13 -55.693 (variable) 14 21.234 3.68 1.63980 34.5 15 -27.788 0.70 1.90043 37.4 16 12.518 4.24 1.59270 35.3 17 -87.908 0.91 18 (aperture) ∞ 2.09 19 42.390 4.09 1.49700 81.7 20 -19.741 (variable) 21 -19.756 0.90 2.00100 29.1 22 -46.915 0.10 1.53344 52.7 23* -32.818 0.25 24 49.974 5.10 1.49700 81.7 25 -15.524 (variable) 26 -39.407 0.70 1.81600 46.6 27 24.127 5.47 1.49700 81.7 28 -23.248 (variable) Image plane ∞ Aspherical data Side 7 K = 0.00000e+00 A 4= 4.48181e-07 A 6= 3.99220e-08 A 8=-9.08985e-11 A10= 1.59194e-12 A12=-4.38981e-15 Page 23 K = 0.00000e+00 A 4= 6.12566e-05 A 6= 1.17826e-07 A 8= 2.22470e-09 A10=-3.70114e-11 A12= 2.37590e-13 Various data Zoom ratio 2.00 Wide-angle, Medium, Telephoto Focal length 6.81 9.58 13.60 F-number 2.85 3.23 3.60 Half-angle 94.94 87.43 89.96 Image height 11.15 14.80 21.64 Lens length 127.71 127.71 127.71 BF 30.73 40.08 49.42 d 4 6.34 6.31 2.10 d13 15.72 6.40 1.27 d20 2.33 3.71 3.67 d25 2.47 1.10 1.14 d28 30.73 40.08 49.42 Lens device group data Group starting plane focal length L1 1 -16.55 L2 5 -42.17 L3 14 26.64 L4 21 47.74 L5 26 -101.75

[0096] [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 55.485 2.30 1.85150 40.8 2 19.371 17.05 3 -1103.546 1.30 1.90525 35.0 4 34.645 (variable) 5 37.524 0.90 1.89286 20.4 6 18.491 0.10 1.58946 30.6 7* 18.199 2.37 8 31.026 8.14 1.78880 28.4 9 -20.624 1.10 1.49700 81.7 10 16.423 5.40 11 -14.389 0.80 1.49700 81.7 12 18.091 3.89 1.61340 44.3 13 -39.413 (variable) 14 18.952 4.42 1.53172 48.8 15 -17.614 0.09 16 -17.868 0.70 1.88300 40.8 17 15.902 4.19 1.59270 35.3 18 -41.659 1.44 19 (aperture) ∞ 1.27 20 34.703 4.01 1.49700 81.7 21 -25.217 (variable) 22 -26.388 0.80 1.88300 40.8 23 -78.439 0.10 1.53344 52.7 24* -49.028 0.15 25 31.715 4.97 1.49700 81.7 26 -18.785 (variable) 27 -53.258 0.75 1.88300 40.8 28 19.564 4.78 1.49700 81.7 29 -25.590 (variable) Image plane ∞ Aspherical data Side 7 K = 0.00000e+00 A 4=-9.88827e-06 A 6= 6.80002e-09 A 8=-9.44113e-12 A10= 1.04890e-12 A12=-2.43934e-15 Page 24 K = 0.00000e+00 A 4= 5.68392e-05 A 6= 1.09227e-07 A 8= 3.24013e-10 A10= 1.13582e-12 A12=-2.42531e-14 Various data Zoom ratio 1.97 Wide-angle, Medium, Telephoto Focal length 6.80 9.52 13.41 F-numbers: 2.86, 3.22, 3.61 Half-angle 95.03 88.50 91.04 Image height 11.15 14.80 21.60 Lens length 126.11 126.11 126.11 BF 30.90 39.23 47.55 d 4 4.47 5.13 1.29 d13 14.12 5.13 0.65 d21 4.03 3.69 2.74 d26 1.58 1.92 2.87 d29 30.90 39.23 47.55 Lens device group data Group starting plane focal length L1 1 -14.82 L2 5 -38.96 L3 14 27.05 L4 22 39.68 L5 27 -68.35

[0097] [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 52.863 2.00 1.85150 40.8 2 19.811 16.64 3 268.068 1.30 2.00100 29.1 4 31.150 (variable) 5 159.698 4.99 1.95375 32.3 6 -30.207 1.20 1.49700 81.7 7 16.611 5.20 8 -17.533 0.80 1.49700 81.7 9 18.643 0.28 10 19.966 6.58 1.78880 28.4 11 -12.466 0.80 2.00100 29.1 12 -61.500 (variable) 13* 55.457 0.10 1.58946 30.6 14 97.068 3.52 1.56732 42.8 15 -14.576 0.05 16 -14.461 0.80 2.00100 29.1 17 22.989 3.89 1.59270 35.3 18 -25.500 0.15 19 52.181 4.70 1.63980 34.5 20 -16.612 0.30 21 (aperture) ∞ (variable) 22 -20.107 0.80 1.95375 32.3 23 -48.225 0.10 1.58946 30.6 24* -37.531 0.15 25 48.217 4.74 1.49700 81.7 26 -16.669 (variable) 27 -101.305 0.80 1.88300 40.8 28 18.672 3.74 1.49700 81.7 29 -30.910 (variable) Image plane ∞ Aspherical data Page 13 K = 0.00000e+00 A 4=-5.40095e-05 A 6=-1.58648e-07 A 8=-6.84435e-09 A10= 1.41530e-10 A12=-1.69897e-12 Page 24 K = 0.00000e+00 A 4= 3.89315e-05 A 6= 1.19235e-07 A 8=-4.99023e-10 A10= 1.75021e-11 A12=-1.12723e-13 Various data Zoom ratio 1.97 Wide-angle, Medium, Telephoto Focal length 6.82 9.56 13.42 F-numbers: 2.83, 3.21, 3.60 Half-angle 94.95 88.37 91.14 Image height 11.15 14.80 21.60 Lens length 123.73 123.73 123.73 BF 32.13 40.19 48.25 d 4 7.71 7.34 3.55 d12 13.02 5.32 1.05 d21 5.99 6.19 5.14 d26 1.25 1.05 2.10 d29 32.13 40.19 48.25 Lens device group data Group starting plane focal length L1 1 -14.97 L2 5 -42.81 L3 13 23.42 L4 22 53.48 L5 27 -82.35

[0098] [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 60.163 2.60 1.83481 42.7 2 21.063 12.33 3 109.832 1.50 1.59522 67.7 4 17.672 (variable) 5 150.019 4.20 1.72047 34.7 6 -51.359 1.58 7 -37.627 0.90 1.89190 37.1 8 91.089 2.62 9 -17.827 0.85 1.49700 81.7 10 19.500 0.71 11 24.491 4.63 1.75520 27.5 12 -127.292 (variable) 13* 32.487 0.05 1.58946 30.6 14 24.928 6.44 1.53172 48.8 15 -10.792 0.85 2.00100 29.1 16 -49.566 0.15 17 260.837 3.61 1.59270 35.3 18 -19.964 0.06 19 -83.132 0.90 1.77250 49.6 20 12.974 5.93 1.59270 35.3 21 -21.635 0.87 22 (aperture) ∞ (variable) 23 20.807 4.87 1.49700 81.7 24 -19.178 0.15 25 -22.797 0.80 2.00100 29.1 26 -66.112 (variable) 27 -2019.764 0.80 1.88300 40.8 28 21.543 2.23 29 31.926 3.93 1.49700 81.7 30 -24.775 (variable) Image plane ∞ Aspherical data Page 13 K = 0.00000e+00 A 4= 7.64291e-06 A 6= 4.60507e-07 A 8=-1.46830e-08 A10= 3.93238e-10 A12=-3.23460e-12 Various data Zoom ratio 2.06 Wide-angle, Medium, Telephoto Focal length 7.22 10.80 14.86 F-numbers: 2.88, 3.61, 4.12 Half-angle 99.23 96.79 92.92 Image height 10.75 16.00 21.60 Lens length 128.99 128.99 128.99 BF 32.52 42.88 49.78 d 4 9.19 8.61 5.93 d12 14.96 5.18 0.95 d22 7.59 6.65 3.60 d26 1.17 2.11 5.15 d30 32.52 42.88 49.78 Lens device group data Group starting plane focal length L1 1 -16.14 L2 5 -36.44 L3 13 35.25 L4 23 46.70 L5 27 -822.66

[0099] [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 58.998 2.50 1.76385 48.5 2 15.716 16.74 3 -118.695 1.40 1.59282 68.6 4 37.945 (variable) 5 52.243 3.96 1.66565 35.6 6 -30.668 0.59 7 -22.962 1.00 1.90043 37.4 8 23.854 (variable) 9 23.518 3.91 1.66565 35.6 10 -20.591 1.00 1.49700 81.7 11 22.024 (Variable) 12 18.264 1.00 1.88300 40.8 13 11.917 4.60 1.68430 26.8 14 -39.891 0.15 15 -32.692 1.00 2.05090 26.9 16 17.207 5.02 1.59410 60.5 17 -18.631 0.50 18 (aperture) ∞ (variable) 19 20.545 2.96 1.53775 74.7 20 -202.410 (variable) 21 -60.820 1.28 1.77250 49.6 22* 52.786 0.52 23 80.866 3.72 1.49700 81.7 24 -23.726 0.15 25 -31.425 1.31 1.88300 40.8 26 52.500 3.91 1.49700 81.7 27 -17.095 (variable) Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4= 2.64230e-05 A 6=-4.03358e-09 A 8= 7.40566e-10 A10=-2.79295e-11 A12= 2.33887e-13 Various data Zoom ratio 2.03 Wide-angle, Medium, Telephoto Focal length 7.24 10.93 14.69 F-number 4.10 4.10 4.10 Half-angle 98.14 94.28 93.38 Image height 10.75 16.00 21.60 Lens length 127.38 127.38 127.38 BF 32.32 43.68 51.25 d 4 13.34 9.39 4.19 d 8 5.91 6.34 6.60 d11 11.80 3.96 1.33 d18 3.21 3.73 3.00 d20 3.58 3.06 3.79 d27 32.32 43.68 51.25 Lens device group data Group starting plane focal length L1 1 -14.79 L2 5 -25.40 L3 9 64.83 L4 12 41.50 L5 19 34.85 L6 21 -442.01

[0100] [Numerical Example 6] Unit: mm Surface data Face number rd nd νd 1 58.154 2.50 1.76385 48.5 2 15.775 16.08 3 -425.603 1.40 1.59282 68.6 4 37.744 (variable) 5 248.610 5.62 1.77047 29.7 6 -19.550 1.00 1.95906 17.5 7 -38.557 (variable) 8 -22.637 1.00 1.91354 36.8 9 28.532 3.85 10 28.132 5.18 1.77047 29.7 11 -21.134 1.00 1.43875 94.7 12 22.654 (variable) 13 24.356 6.32 1.68430 26.8 14 -13.488 1.00 2.00100 29.1 15 28.481 4.91 1.51823 58.9 16 -15.181 0.40 17 (aperture) ∞ (variable) 18 22.580 3.05 1.49700 81.7 19 -104.450 (variable) 20 -34.188 1.28 1.76450 49.1 21* 87.503 2.04 22 32.469 4.26 1.49700 81.7 23 -18.234 0.15 24 -176.617 1.31 1.88300 40.8 25 19.236 3.68 1.49700 81.7 26 -61.995 (variable) Image plane ∞ Aspherical data Page 21 K = 0.00000e+00 A 4= 3.50880e-05 A 6= 1.70964e-08 A 8= 3.91104e-09 A10=-9.58126e-11 A12= 7.92141e-13 Various data Zoom ratio 2.06 Wide-angle, Medium, Telephoto Focal length 7.25 11.01 14.97 F-number 4.10 4.10 4.10 Half-angle 97.86 93.05 90.55 Image height 10.75 16.00 21.60 Lens length 131.41 131.41 131.41 BF 32.32 43.52 50.99 d 4 11.62 9.61 3.44 d 7 1.54 1.48 2.68 d12 13.54 4.41 1.90 d17 4.43 4.43 3.35 d19 1.92 1.92 3.00 d26 32.32 43.52 50.99 Lens device group data Group starting plane focal length L1 1 -16.36 L2 5 54.77 L3 8 -23.38 L4 13 42.94 L5 18 37.66 L6 20 -345.10

[0101] The various values ​​in each numerical example are summarized in Table 1 below.

[0102] [Table 1]

[0103] [Imaging device] Next, we will describe an imaging device to which the lens device L0 of this embodiment is applied. Figure 16 is a schematic diagram of the imaging device 10 of this embodiment. The imaging device 10 comprises a camera body 13, a lens device 11 which is the same as in any of the embodiments 1 to 6 described above, and a light-receiving element 12 which converts the optical image formed by the lens device 11 into photoelectricity.

[0104] The imaging device 10 of this embodiment has a lens device 11 that is compact and has good optical characteristics, so it can obtain high-quality images.

[0105] Furthermore, an image sensor such as a CCD or CMOS sensor can be used as the light-receiving element 12. In this case, the output image can be made higher quality by electrically correcting various aberrations such as distortion and chromatic aberration of the image acquired by the light-receiving element 12.

[0106] Furthermore, the lens apparatus L0 in each of the above embodiments can be applied not only to digital still cameras as shown in Figure 16, but also to various optical instruments such as silver halide film cameras, video cameras, and telescopes.

[0107] Next, we will describe the specific correction process in the imaging device 300 of each embodiment.

[0108] Figure 17 is a flowchart showing the correction process in the imaging device 300.

[0109] S101 marks the start of processing, and the program proceeds to S102.

[0110] In S102, the camera communication means 305 receives the actual focal length variation rate table and the light-shielding area table transmitted from the lens device L0, and proceeds to S103.

[0111] In S103, the camera communication means 305 receives the current actual focal length and zoom position transmitted from the lens device L0, and proceeds to S104.

[0112] In S104, the imaging means 303 transmits the photoelectrically converted signal to the image generation means 306, and the process proceeds to S105.

[0113] In S105, the image generation means 306 generates an image based on the signal received from the imaging means 303, transmits it to the correction means 307, and proceeds to S106.

[0114] In S106, the correction means 307 performs a correction process and proceeds to S107.

[0115] In S107, if the correction process is to be terminated, the process proceeds to S108 and ends. Otherwise, the process proceeds to S103. Termination of the process occurs, for example, when the camera 200 is powered off.

[0116] Next, we will describe the specific correction method of the correction means 307 performed in S106.

[0117] Figure 18 is a schematic diagram of the first correction method and flowchart of the correction means 307. Figure 18 shows the uncorrected image when the imaging means 303 captures images at first, second, and third different focal positions, the corrected image obtained by correcting each uncorrected image with the correction means 307, and the post-corrected image obtained by further correcting the corrected image with the correction means 307. Note that the relationship between the uncorrected image, corrected image, and post-corrected image at each focal position is an example in this embodiment and is not limited to this.

[0118] S201 marks the start of processing, and the program proceeds to S102.

[0119] In S202, the correction means 307 corrects the magnification of the image before correction by multiplying the magnification of the image before correction by "1 / actual focal length variation rate" based on the information of the actual focal length variation rate, and then proceeds to S203.

[0120] In S203, the correction means 307 checks the light-shielding area table to see if there is a light-shielding area at the current zoom position. If there is a light-shielding area, the process proceeds to S204; otherwise, the process proceeds to S205 and terminates.

[0121] In S204, the correction means 307 performs a trimming process to remove the light-shielding area from the corrected image whose magnification was corrected in S202, and then proceeds to S205 to complete the process.

[0122] As shown in the diagram, by performing the correction process using the first correction method, it is possible to eliminate unwanted light-shielding areas while obtaining the same field of view at any focal position.

[0123] Figure 19 is a schematic diagram of the second correction method and flowchart of the correction means 307. In the second correction method, In S301, processing begins, and the program proceeds to S302.

[0124] In S302, the correction means 307 checks the received light-shielding area table to see if there is a light-shielding area at the current zoom position. If there is, it proceeds to S303; otherwise, it proceeds to S304.

[0125] In S303, the correction means 307 multiplies the pre-correction image by "1 / actual focal length variation rate", performs a trimming process to remove the light-shielding area, and proceeds to S305 to terminate the process.

[0126] In S304, the correction means 307 multiplies the uncorrected image by "1 / actual focal length variation rate", crops it to the image size, and proceeds to S305 to complete the process.

[0127] In the second correction method, the area of ​​the correction image that needs to be generated by the correction means 307 is reduced, making it possible to shorten the correction process.

[0128] Thus, by performing the correction process using the second correction method, it is possible to obtain the same field of view at any focal position, as shown in the figure, while eliminating unnecessary light-shielding areas and further shortening the correction process.

[0129] Figure 20 is a schematic diagram relating to the third correction method and flowchart of the correction means 307.

[0130] S401 marks the start of processing, and the program proceeds to S402.

[0131] In S402, the correction means 307 checks the received light-shielding area table to see if there is a light-shielding area at the current zoom position. If there is, it proceeds to S403; otherwise, it proceeds to S404.

[0132] In S403, the correction means 307 multiplies the pre-correction image by "1 / actual focal length variation rate", performs a trimming process to remove the light-shielding area, and proceeds to S405.

[0133] In S404, the correction means 307 multiplies the pre-correction image by "1 / actual focal length variation rate", crops it to the image size, and proceeds to S407 to complete the process.

[0134] In S405, if the angle of view of the corrected image is 180° or more, the process proceeds to S406; if it is less than 180°, the process proceeds to S407 and the process ends.

[0135] In S406, the correction means 307 performs trimming processing to delete the region with an angle of view of 180° or more in the corrected image, and then proceeds to S407 to end the process.

[0136] The zoom position of the lens device L0 is wide-angle, and there may be cases where there are unnecessary imaging regions depending on the user's usage scene. For example, when the angle of view exceeds 180° depending on the zoom position, the angle of view portion of 180° or more may be unnecessary as a region because the photographer or the imaging equipment is reflected in the imaging region. In such a case, in the imaging region corresponding to the zoom position with an angle of view of 180° or more, by performing trimming correction processing so that the angle of view is less than 180° at any zoom position, unnecessary reflections in the captured image can be removed.

[0137] Note that setting the angle of view to 180° or more is an example in this embodiment, but it is not limited to this, and different angles of view may be used.

[0138] FIG. 21 is a schematic diagram regarding the fourth correction method of the correction means 307.

[0139] In the fourth correction method, in S104, the imaging means 303 calculates in advance the region to be trimmed from the information received in S102, and performs imaging after excluding that region. Then, in S106, the same correction method as the second correction method is implemented.

[0140] By performing the correction process according to the fourth correction method, as shown in the figure, at any focal position, it is possible to obtain the same angle of view while excluding unnecessary light-shielding regions, and it is also possible to shorten the correction process.

[0141] Although preferred embodiments of the present invention have been described above as one aspect of the present invention, the present invention is not limited to these embodiments, and various combinations, modifications, and changes are possible within the scope of its gist.

[0142] The imaging system may include the lens device L0 of each embodiment and a control unit that controls the lens device L0. In this case, the control unit can control the lens device L0 so that each lens group moves during zooming, focusing, or image blur correction. At this time, the control unit does not need to be integrally configured with the lens device L0; the control unit may be configured separately from the lens device L0. For example, a control unit located far away from the drive unit that drives each lens of the lens device L0 may be configured to include a transmission unit that sends control signals for controlling the lens device L0. With such a control unit, the lens device L0 can be remotely operated.

[0143] The imaging system may be configured to control the lens device L0 in response to user input, by providing an operating unit such as a controller or buttons in the control unit for remotely operating the lens device L0. For example, the operating unit may include a zoom-in button and a zoom-out button. In this case, the system should be configured such that when the user presses the zoom-in button, the magnification of the lens device L0 increases, and when the user presses the zoom-out button, the magnification of the lens device L0 decreases, by sending a signal from the control unit to the drive unit of the lens device L0.

[0144] The imaging system may have a display unit, such as an LCD panel, that displays information regarding the movement of the lens device L0 during zooming. This information regarding the zoom of the lens device L0 may include, for example, the zoom magnification and the amount of movement of each lens group during zooming. In this case, the user can remotely control the lens device L0 via the control unit while viewing the zoom information of the lens device L0 displayed on the display unit. The display unit and the control unit may be integrated, for example, by employing a touch panel.

[0145] In the lens device L0 of each embodiment, the correction means 307 may not refer to the light-shielding area table stored in the storage means 207, but may directly refer to whether there is a light-shielding area at the current zoom position from third optical information relating to the image area at the current zoom position. For example, a reference point may be set in the imageable area, and the light-shielding area may be referred to from the brightness difference with the reference brightness at the reference point.

[0146] Furthermore, in the lens device L0 of each embodiment, any of the first to fourth correction methods shown in Figures 18 to 21 may be adopted.

[0147] Furthermore, each embodiment disclosed includes the following configuration.

[0148] (Composition 1) A lens device that is detachable from an imaging device having an image sensor, and whose half-angle of view corresponding to the maximum image height at infinity focus at the wide-angle end exceeds 90°, It includes a first communication means for communicating with the imaging device, The lens device is characterized in that the first communication means transmits to the imaging device information regarding the region of an image formed by the lens device on the image sensor.

[0149] (Configuration 2) The lens device according to configuration 1, characterized in that the first communication means transmits information regarding the change in focal length due to focusing of the lens device to the imaging device.

[0150] (Composition 3) The lens device according to configuration 1 or 2, characterized in that the first communication means transmits information regarding the zoom position of the lens device to the imaging device.

[0151] (Composition 4) It has a first lens group having negative refractive power, arranged sequentially from the object side to the image side, and a rear group including one or more lens groups that have positive refractive power as a whole. When zooming, the distance between adjacent lenses changes. The focusing group, which consists of one or more lens groups included in the rear group, is configured to move in the optical axis direction during focusing, and is the lens device according to any one of Configurations 1 to 3.

[0152] (Configuration 5) When the focal length of the first lens group is fL1 and the focal length of the lens device at the wide-angle end is fw, -3.0 < fL1 / fw < -1.7 The lens device according to any one of Configurations 1 to 4, characterized by satisfying the conditional expression.

[0153] (Configuration 6) The rear group includes a second lens group having a negative refractive power. When the focal length of the second lens group is fL2 and the focal length of the first lens group is fL1, -5.0 < |fL2| / fL1 < -1.1 The lens device according to any one of Configurations 1 to 5, characterized by satisfying the conditional expression.

[0154] (Configuration 7) When the focal length of the lens G1 disposed closest to the object side in the first lens group is fG1 and the focal length of the first lens group is fL1, 1.4 < fG1 / fL1 < 3.0 The lens device according to any one of Configurations 1 to 6, characterized by satisfying the conditional expression.

[0155] (Configuration 8) When the focal length of the lens G1 disposed closest to the object side in the first lens group is fG1 and the focal length of the lens G2 disposed adjacent to the image side of the lens G1 is fG2, 0.40 < fG1 / fG2 < 1.60 The lens device according to any one of Configurations 1 to 7, characterized by satisfying the conditional expression.

[0156] (Configuration 9) When the focal length of the aforementioned focus group is fLF and the focal length of the lens device at the wide-angle end is fw, 3.5 <fLF / fw<15.0 A lens device according to any one of configurations 1 to 8, characterized in that it satisfies the following conditional expression.

[0157] (Composition 10) When the focal length of the aforementioned focusing group is fLF and the focal length of the first lens group is fL1, -4.1 <fLF / fL1<-1.8 A lens device according to any one of configurations 1 to 9, characterized in that it satisfies the following conditional expression.

[0158] (Composition 11) When the focal length of the first lens group is fL1 and the focal length of the rear group at the wide-angle end is fLRw, -1.30 <fL1 / fLRw<-0.55 A lens device according to any one of configurations 1 to 10, characterized by satisfying the following conditional expression.

[0159] (Composition 12) When the back focus at the wide-angle end is Skw and the focal length of the lens device at the wide-angle end is fw, 2.0 <Skw / fw<6.0 A lens device according to any one of configurations 1 to 11, characterized by satisfying the following conditional expression.

[0160] (Composition 13) The aforementioned rear group has an aperture diaphragm, When DSPw is the distance along the optical axis from the aperture diaphragm to the lens surface closest to the image at the wide-angle end, and Skw is the back focus at the wide-angle end, 0.40 <DSPw / Skw<1.00 A lens device according to any one of configurations 1 to 12, characterized by satisfying the following conditional expression.

[0161] (Composition 14) When the refractive index of the material of lens G1, which is positioned closest to the object in the first lens group, is ndG1 with respect to the d line, 1.65 <ndG1<2.20 A lens device according to any one of configurations 1 to 13, characterized by satisfying the following conditional expression.

[0162] (Composition 15) In the first lens group, the lens G1 positioned closest to the object is a negative lens having a meniscus shape with its convex surface facing the object. When the radius of curvature of the object-side lens surface of lens G1 is R1, and the radius of curvature of the image-side lens surface of lens G1 is R2, 1.3 < (R1 + R2) / (R1 - R2) < 3.0 A lens device according to any one of configurations 1 to 14, characterized by satisfying the following conditional expression.

[0163] (Composition 16) When the maximum image height at the telephoto end is Yta and the maximum image height at the wide-angle end is Ywa, 1.5 <Yta / Ywa<3.0 A lens device according to any one of configurations 1 to 15, characterized by satisfying the following conditional expression.

[0164] (Composition 17) The lens device according to any one of configurations 1 to 16, characterized in that the first lens group has a plurality of negative lenses.

[0165] (Composition 18) The lens device according to any one of configurations 1 to 17, characterized in that the focus group consists of two or fewer lenses.

[0166] (Composition 19) A lens device according to any one of configurations 1 to 18, characterized in that all lens surfaces included in the first lens group are spherical.

[0167] (Composition 20) The lens device according to any one of configurations 1 to 19, characterized in that the aforementioned rear group includes three or more lens groups whose spacing changes during zooming.

[0168] (Composition 21) It comprises a first lens barrel that holds the first lens group, The lens G1 closest to the object in the first lens group is a meniscus lens with its convex surface facing the object. The lens device according to any one of configurations 1 to 20, characterized in that the vertex of the object-side surface of the lens G1 is located closer to the object than the first lens barrel.

[0169] (Composition 22) The aforementioned rear group has an aperture diaphragm, The lens device according to any one of configurations 1 to 21, characterized in that the focus group is arranged on the image side of the aperture diaphragm.

[0170] (Composition 23) The lens device according to any one of configurations 1 to 22, characterized in that the rear group comprises 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 a fifth lens group having negative refractive power, all arranged in order from the object side to the image side.

[0171] (Composition 24) The lens device according to any one of configurations 1 to 23, characterized in that the rear group comprises a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

[0172] (Composition 25) The lens device according to any one of configurations 1 to 24, characterized in that the rear group comprises a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

[0173] (Composition 26) An imaging device that is detachable from any one of the configurations 1 to 25, and is characterized by comprising the image sensor.

[0174] (Composition 27) An imaging device equipped with an image sensor, It is detachable from lens devices whose half-angle of view, corresponding to the maximum image height at infinity focus at the wide-angle end, exceeds 90°. The lens device includes a first communication means for communicating with the imaging device. The imaging device is characterized in that the first communication means transmits to the imaging device information regarding the region of an image formed on the image sensor by the lens device.

[0175] (Composition 28) The imaging device includes correction means for correcting an image generated based on an image signal output from the image sensor, When the information relating to the zoom position is considered the first optical information, the information relating to the variation in focal length is considered the second optical information, and the information relating to the image region is considered the third optical information, The imaging apparatus according to configuration 26 or 27, characterized in that the correction means corrects the image based on the first to third optical information.

[0176] (Composition 29) The imaging device includes a second communication means for communicating with the lens device. The second communication means receives the first and second optical information from the first communication means, The imaging apparatus according to any one of the configurations 26 to 28, characterized in that the correction means performs a first correction that corrects the magnification of the image based on the first and second optical information.

[0177] (Composition 30) The second communication means receives the third optical information from the first communication means, The imaging apparatus according to any one of configurations 26 to 29, characterized in that the correction means performs a second correction on the image that has undergone the first correction, by trimming it based on the third optical information.

[0178] (Composition 31) The imaging apparatus according to any one of the configurations 26 to 30, characterized in that the correction means determines a correction region for performing the first and second corrections from the image generated by the image generation means.

[0179] (Composition 32) The imaging apparatus according to any one of configurations 26 to 31, characterized in that the correction means determines the region of the image generated by the image generation means, excluding the region that is darker than the reference brightness, as the correction region.

[0180] (Composition 33) The imaging apparatus according to any one of the configurations 26 to 32, characterized in that the correction means limits the area to be imaged by the imaging apparatus based on the first optical information.

[0181] (Composition 34) An imaging system characterized by comprising a lens device according to any one of configurations 1 to 25 and an imaging device according to any one of configurations 26 to 33. [Explanation of Symbols]

[0182] 200 Lens device 206 First means of communication 300 Imaging devices 303 Image sensor

Claims

1. A lens device that is detachable from an imaging device having an image sensor, and whose half-angle of view corresponding to the maximum image height at infinity focus at the wide-angle end exceeds 90°, It is equipped with a first communication means for communicating with the imaging device, The lens device is characterized in that the first communication means transmits to the imaging device information regarding the region of an image formed by the lens device on the image sensor.

2. The lens device according to claim 1, characterized in that the first communication means transmits information regarding the change in focal length due to focusing of the lens device to the imaging device.

3. The lens device according to claim 2, characterized in that the first communication means transmits information regarding the zoom position of the lens device to the imaging device.

4. It has a first lens group having negative refractive power, arranged sequentially from the object side to the image side, and a rear group including one or more lens groups that have positive refractive power as a whole. When zooming, the distance between adjacent lens groups changes. The lens device according to claim 3, characterized in that the focus group, which consists of one or more lens groups from among the lens groups included in the aforementioned rear group, moves in the direction of the optical axis during focusing.

5. When the focal length of the first lens group is fL1 and the focal length of the lens device at the wide-angle end is fw, -3.0<fL1 / fw<-1.7 The lens device according to claim 4, characterized in that it satisfies the following condition.

6. The aforementioned rear group includes a second lens group having negative refractive power. When the focal length of the second lens group is fL2 and the focal length of the first lens group is fL1, -5.0<|fL2| / fL1<-1.1 The lens device according to claim 4, characterized in that it satisfies the following condition.

7. When the focal length of the lens G1 positioned closest to the object in the first lens group is fG1, and the focal length of the first lens group is fL1, 1.4<fG1 / fL1<3.0 The lens device according to claim 4, characterized in that it satisfies the following condition.

8. When the focal length of lens G1, which is positioned closest to the object in the first lens group, is fG1, and the focal length of lens G2, which is positioned adjacent to lens G1 on the image side, is fG2, 0.40<fG1 / fG2<1.60 The lens device according to claim 4, characterized in that it satisfies the following condition.

9. When the focal length of the aforementioned focus group is fLF and the focal length of the lens device at the wide-angle end is fw, 3.5<fLF / fw<15.0 The lens device according to claim 4, characterized in that it satisfies the following condition.

10. When the focal length of the aforementioned focus group is fLF and the focal length of the first lens group is fL1, -4.1<fLF / fL1<-1.8 The lens device according to claim 4, characterized in that it satisfies the following condition.

11. When the focal length of the first lens group is fL1 and the focal length of the rear group at the wide-angle end is fLRw, -1.30<fL1 / fLRw<-0.55 The lens device according to claim 4, characterized in that it satisfies the following condition.

12. When the back focus at the wide-angle end is Skw and the focal length of the lens device at the wide-angle end is fw, 2.0<Skw / fw<6.0 The lens device according to claim 4, characterized in that it satisfies the following condition.

13. The aforementioned rear group has an aperture diaphragm, When DSPw is the distance along the optical axis from the aperture diaphragm to the lens surface closest to the image at the wide-angle end, and Skw is the back focus at the wide-angle end, 0.40<DSPw / Skw<1.00 The lens device according to claim 4, characterized in that it satisfies the following condition.

14. When the refractive index of the material of lens G1, which is positioned closest to the object in the first lens group, is ndG1 with respect to the d line, 1.65<ndG1<2.20 The lens device according to claim 4, characterized in that it satisfies the following condition.

15. In the first lens group, the lens G1 positioned closest to the object is a negative lens having a meniscus shape with its convex surface facing the object. When the radius of curvature of the object-side lens surface of the lens G1 is R1, and the radius of curvature of the image-side lens surface of the lens G1 is R2, 1.3<(R1+R2) / (R1-R2)<3.0 The lens device according to claim 4, characterized in that it satisfies the following condition.

16. When Yta is the maximum image height at the telephoto end and Ywa is the maximum image height at the wide-angle end, 1.5<Yta / Ywa<3.0 The lens device according to claim 4, characterized in that it satisfies the following condition.

17. The lens device according to claim 4, characterized in that the first lens group has a plurality of negative lenses.

18. The lens device according to claim 4, characterized in that the focus group consists of two or fewer lenses.

19. The lens device according to claim 4, characterized in that all lens surfaces included in the first lens group are spherical.

20. The lens device according to claim 4, characterized in that the aforementioned rear group includes three or more lens groups whose spacing changes during zooming.

21. It comprises a first lens barrel that holds the first lens group, The lens G1 closest to the object in the first lens group is a meniscus lens with its convex surface facing the object. The lens device according to claim 4, characterized in that the vertex of the object-side surface of the lens G1 is located closer to the object than the first lens barrel.

22. The aforementioned rear group has an aperture diaphragm, The lens device according to claim 4, characterized in that the focus group is arranged on the image side of the aperture diaphragm.

23. The lens device according to claim 4, characterized in that the rear group comprises 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 a fifth lens group having negative refractive power, all arranged in order from the object side to the image side.

24. The lens device according to claim 4, characterized in that the rear group comprises a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

25. The lens device according to claim 4, characterized in that the rear group comprises a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

26. An imaging device that is detachable from the lens device described in any one of claims 3 to 25, and is characterized by comprising the image sensor.

27. The imaging device includes correction means for correcting an image generated based on an image signal output from the image sensor, When the information relating to the zoom position is considered the first optical information, the information relating to the variation in focal length is considered the second optical information, and the information relating to the image region is considered the third optical information, The imaging apparatus according to claim 26, characterized in that the correction means corrects the image based on the first to third optical information.

28. The imaging device includes a second communication means for communicating with the lens device. The second communication means receives the first and second optical information from the first communication means, The imaging apparatus according to claim 27, characterized in that the correction means performs a first correction to correct the magnification of the image based on the first and second optical information.

29. The second communication means receives the third optical information from the first communication means, The imaging apparatus according to claim 28, characterized in that the correction means performs a second correction on the image that has undergone the first correction, by trimming it based on the third optical information.

30. The imaging apparatus according to claim 29, characterized in that the correction means determines a correction region for performing the first and second corrections on the image.

31. The imaging apparatus according to claim 30, characterized in that the correction means determines the area in the image excluding the area darker than the reference brightness as the correction area.

32. The imaging apparatus according to claim 30, characterized in that the correction means limits the area to be imaged by the imaging apparatus based on the first optical information.

33. An imaging device equipped with an image sensor, It is detachable from lens devices where the half-angle of view corresponding to the maximum image height at infinity focus at the wide-angle end exceeds 90°. The lens device includes a first communication means for communicating with the imaging device. The imaging device is characterized in that the first communication means transmits to the imaging device information regarding the region of an image formed on the image sensor by the lens device.

Images