JP7395326B2 - Lens device, imaging device, communication method, and program - Google Patents

Description

The present invention relates to a lens device and an imaging device that perform focus detection using a phase difference method.

2. Description of the Related Art Conventionally, imaging apparatuses are known that perform focus detection using a phase difference method based on pixel signals output from an imaging element. Further, a lens device including an optical element having a transmittance distribution has been proposed. Such an optical element is provided to smooth the edges of a blurred image, and can realize a blur depiction that cannot be obtained with a normal imaging optical system, thereby expanding the range of photographic expression.

Patent Document 1 discloses that a parameter (conversion coefficient) regarding the ratio between the phase difference and the defocus amount is calculated based on the transmittance distribution of the optical element, the incident angle range of the luminous flux, and the light receiving sensitivity distribution of the image sensor. An imaging device is disclosed. By using this information, it is possible to calculate a conversion coefficient (defocus conversion coefficient) used to calculate the amount of defocus in an imaging device equipped with an optical element having a transmittance distribution.

Patent No. 6171106

However, it is difficult to store the transmittance distribution of the optical element, the incident angle range of the luminous flux, and the light receiving sensitivity distribution of the image sensor in the imaging device, and calculate the defocus conversion coefficient based on this information each time focus detection is performed. requires increased storage capacity and computational time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lens device, an imaging device, a communication method, and a program that can calculate a defocus conversion coefficient without increasing storage capacity or calculation time.

A lens device according to one aspect of the present invention is a lens device that can be attached to and detached from an imaging device, and includes an imaging optical system having a transmittance distribution layer that is rotationally symmetrical with respect to an optical axis, and the imaging optical system capable of receiving light from an imaging element. The aperture information includes a storage means for storing aperture information that defines an area , and a communication means for transmitting the aperture information to the imaging device, and the aperture information is configured to calculate a defocus conversion coefficient when the imaging device performs focus detection. It is used for calculation and includes first aperture information regarding a baseline length corresponding to a change in the baseline length due to the transmittance distribution layer.

Another aspect of the present invention is an imaging device having a detachable lens device, which captures images from an imaging element and the lens device using an imaging optical system having a transmittance distribution layer that is rotationally symmetrical with respect to an optical axis. It has a communication means for receiving aperture information that defines a light-receiving area of the element , and a calculation means for calculating a defocus conversion coefficient based on the aperture information, and the aperture information includes a base line length by the transmittance distribution layer. The first aperture information includes first aperture information regarding the baseline length corresponding to the change in the base line length.

A communication method according to another aspect of the present invention is a communication method between an imaging device and a lens device including an imaging optical system having a transmittance distribution layer that is rotationally symmetrical with respect to an optical axis, the method comprising: The method includes a step of acquiring aperture information that defines a light-receiving area of an image sensor by the imaging optical system, and a step of transmitting the aperture information to the imaging device. It is used to calculate a defocus conversion coefficient when carrying out the process, and includes first aperture information regarding the base line length corresponding to the change in the base line length due to the transmittance distribution layer.

A program according to another aspect of the present invention causes a computer to execute the communication method.

Other objects and features of the invention are illustrated in the following examples.

According to the present invention, it is possible to provide a lens device, an imaging device, a communication method, and a program that can calculate a defocus conversion coefficient without increasing storage capacity and calculation time.

2 is a block diagram of an imaging device in Examples 1 and 2. FIG. FIG. 3 is a schematic diagram of a pixel arrangement of an image sensor in each example. FIG. 2 is a schematic plan view and a schematic cross-sectional view of a pixel of an image sensor in each example. FIG. 3 is a schematic explanatory diagram of pixels of an image sensor and pupil division in each example. FIG. 2 is a schematic explanatory diagram of an image sensor and pupil division in each example. FIG. 3 is a schematic relationship diagram between the amount of defocus and the amount of image shift in each example. FIG. 6 is a schematic explanatory diagram of the base line length in the case where there is no transmittance distribution layer in each example. FIG. 6 is a schematic explanatory diagram of the base line length in the case where there is no transmittance distribution layer in each example. FIG. 3 is a schematic explanatory diagram of a transmittance distribution layer in each example. FIG. 3 is a schematic explanatory diagram of the base line length when there is a transmittance distribution layer in each example. FIG. 3 is a schematic explanatory diagram of the base line length when there is a transmittance distribution layer in each example. FIG. 3 is a schematic explanatory diagram of first aperture information in each example. FIG. 3 is a schematic explanatory diagram of first aperture information in each example. 7 is a flowchart of obtaining aperture information in Example 1. FIG. 7 is a flowchart for calculating a defocus conversion coefficient in Example 2. FIG. 3 is a block diagram of an imaging device in Example 3. FIG. 7 is a flowchart of obtaining aperture information in Example 3. FIG. 7 is a schematic explanatory diagram of third aperture information and fourth aperture information in Example 3; FIG. 7 is a schematic explanatory diagram of third aperture information and fourth aperture information in Example 3; FIG. 7 is a schematic explanatory diagram of third aperture information and fourth aperture information in Example 3;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Configuration of imaging device)
First, with reference to FIG. 1, the configuration of an imaging apparatus in Example 1 of the present invention will be described. FIG. 1 is a block diagram of an imaging device (single-lens reflex digital camera with interchangeable lenses) 10 in this embodiment. The imaging device 10 is a camera system (imaging system) that includes a lens unit (interchangeable lens, lens device) 100 and a camera body (imaging device main body) 120. The lens unit 100 is detachably attached to the camera body 120 via a mount M shown by a dotted line in FIG. However, this embodiment is not limited to this, and can also be applied to an imaging device (digital camera) in which a lens unit (imaging optical system) and a camera body are integrally configured. Further, the present embodiment is not limited to digital cameras, but can also be applied to other imaging devices such as video cameras.

The lens unit 100 includes a first lens group 101 as an optical system, an aperture 102, a second lens group 103, a focus lens group (hereinafter simply referred to as "focus lens") 104, a transmittance distribution layer 105, and a driving/distributing layer 105. It has a control system. In this way, the lens unit 100 is a photographic lens (imaging optical system) that includes the focus lens 104 and forms a subject image (optical image).

The first lens group 101 is disposed at the tip of the lens unit 100 and is held movable in the optical axis direction OA. The diaphragm 102 adjusts the amount of light during photographing by adjusting its aperture diameter, and also functions as a shutter for adjusting the exposure time during still image photographing. The diaphragm 102 and the second lens group 103 are movable together in the optical axis direction OA, and achieve a zoom function in conjunction with the forward and backward movements of the first lens group 101. The focus lens 104 is movable in the optical axis direction OA, and the subject distance (focusing distance) on which the lens unit 100 focuses changes depending on its position. By controlling the position of the focus lens 104 in the optical axis direction OA, focus adjustment (focus control) that adjusts the focusing distance of the lens unit 100 is possible. The transmittance distribution layer 105 is an optical element having a rotationally symmetric transmittance distribution about the optical axis. In this embodiment, the transmittance distribution layer 105 will be described as having a structure in which the transmittance is highest at the center of the optical axis, and the transmittance decreases as the distance from the center of the optical axis increases.

The drive/control system includes a zoom actuator 111, an aperture actuator 112, a focus actuator 113, a zoom drive circuit 114, an aperture drive circuit 115, a focus drive circuit 116, a lens MPU 117, and a lens memory 118. The zoom drive circuit 114 uses the zoom actuator 111 to drive the first lens group 101 and the third lens group 103 in the optical axis direction OA, and controls the angle of view of the optical system of the lens unit 100 (performs a zoom operation). . The diaphragm drive circuit 115 drives the diaphragm 102 using the diaphragm actuator 112, and controls the aperture diameter and opening/closing operation of the diaphragm 102. The focus drive circuit 116 drives the focus lens 104 in the optical axis direction OA using the focus actuator 113 to control the focusing distance of the optical system of the lens unit 100 (performs focus control). Further, the focus drive circuit 116 has a function as a position detection unit that detects the current position (lens position) of the focus lens 104 using the focus actuator 113.

A lens MPU (processor) 117 performs all calculations and controls related to the lens unit 100, and controls a zoom drive circuit 114, an aperture drive circuit 115, and a focus drive circuit 116. Further, the lens MPU 117 is connected to the camera MPU 125 through the mount M, and is a communication means for communicating commands and data. For example, the lens MPU 117 detects the position of the focus lens 104 and notifies lens position information in response to a request from the camera MPU 125. The lens position information includes the position of the focus lens 104 in the optical axis direction OA, the position and diameter of the exit pupil in the optical axis direction OA when the imaging optical system is not moving, and the lens frame that limits the luminous flux of the exit pupil. It includes information such as the position and diameter in the optical axis direction OA. Further, the lens MPU 117 controls the zoom drive circuit 114, the aperture drive circuit 115, and the focus drive circuit 116 in response to a request from the camera MPU 125. A lens memory (storage means) 118 stores optical information necessary for automatic focus adjustment (AF control). The camera MPU 125 controls the operation of the lens unit 100 by, for example, executing a program stored in a built-in nonvolatile memory or the lens memory 118.

The camera body 120 has an optical low-pass filter 121, an image sensor 122, and a drive/control system. The optical low-pass filter 121 and the imaging device 122 function as an imaging unit (imaging means) that photoelectrically converts a subject image (optical image) formed through the lens unit 100 and outputs image data. In this embodiment, the image sensor 122 photoelectrically converts a subject image formed through an imaging optical system, and outputs an imaging signal and a focus detection signal as image data. Further, in this embodiment, the first lens group 101, the diaphragm 102, the second lens group 103, the focus lens 104, and the optical low-pass filter 121 constitute an imaging optical system.

The optical low-pass filter 121 reduces false colors and moiré in captured images. The image sensor 122 is composed of a CMOS image sensor and its peripheral circuit, and has m pixels in the horizontal direction and n pixels in the vertical direction (m and n are integers of 2 or more). The image sensor 122 of this embodiment also serves as a focus detection element, has a pupil division function, and is a pupil division pixel capable of phase difference detection method focus detection (phase difference AF) using image data (image signal). has. The image processing circuit 124 generates data for phase difference AF and image data for display, recording, and contrast AF (TVAF) based on the image data output from the image sensor 122.

The drive/control system includes an image sensor drive circuit 123, an image processing circuit 124, a camera MPU 125, a display 126, an operation switch group (operation SW) 127, a memory 128, and a phase difference AF section (imaging plane phase difference focus detection section) 129. , and a TVAF section (TVAF focus detection section) 130. The image sensor drive circuit 123 controls the operation of the image sensor 122, performs A/D conversion on an image signal (image data) output from the image sensor 122, and transmits the converted image signal to the camera MPU 125. The image processing circuit 124 performs general image processing performed in a digital camera, such as γ conversion, white balance adjustment processing, color interpolation processing, and compression encoding processing, on the image signal output from the image sensor 122. The image processing circuit 124 also generates a signal for phase difference AF.

A camera MPU (processor, control unit) 125 performs all calculations and controls related to the camera body 120. That is, the camera MPU 125 controls the image sensor drive circuit 123, the image processing circuit 124, the display 126, the operation switch group 127, the memory 128, the phase difference AF section 129, and the TVAF section 130. Further, the camera MPU 125 is connected to the lens MPU 117 via the signal line of the mount M, and is a communication means for communicating commands and data with the lens MPU 117. The camera MPU 125 issues a request to the lens MPU 117 to acquire the lens position and drive the lens with a predetermined drive amount, and also issues a request from the lens MPU 117 to acquire optical information specific to the lens unit 100 .

The camera MPU 125 includes a ROM 125a that stores a program for controlling the operation of the camera body 120, a RAM (camera memory) 125b that stores variables, and an EEPROM 125c that stores various parameters. Further, the camera MPU 125 executes focus detection processing based on a program stored in the ROM 125a. In the focus detection process, a known correlation calculation process is performed using a pair of image signals obtained by photoelectrically converting an optical image formed by a light flux that has passed through different pupil areas (pupil partial areas) of the imaging optical system. .

The display 126 is composed of a liquid crystal display (LCD) or the like, and displays information regarding the photographing mode of the imaging device 10, a preview image before photographing, a confirmation image after photographing, a focus state display image at the time of focus detection, and the like. The operation switch group 127 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The memory (storage means) 128 is a removable flash memory and records captured images.

The phase difference AF unit 129 performs focus detection processing using a phase difference detection method based on an image signal of focus detection image data obtained from the image sensor 122 and the image processing circuit 124. More specifically, the image processing circuit 124 generates a pair of image data formed by a light beam passing through a pair of pupil regions of the imaging optical system as focus detection data, and the phase difference AF unit 129 generates a pair of image data as focus detection data. The amount of defocus is detected based on the amount of deviation of image data. In this way, the phase difference AF unit 129 of this embodiment performs phase difference AF (imaging surface phase difference AF) based on the output of the image sensor 122 without using a dedicated AF sensor. In this embodiment, the phase difference AF section 129 includes an acquisition means 129a and a calculation means 129b. The acquisition unit 129a acquires the aperture information received from the lens unit 100 from the camera MPU 125. The calculation means 129b calculates a defocus conversion coefficient based on the aperture information. Note that at least a part of the phase difference AF section 129 (a part of the acquisition means 129a or the calculation means 129b) may be provided in the camera MPU 125.

The TVAF unit 130 performs focus detection processing using a contrast detection method based on the TVAF evaluation value (contrast information of image data) generated by the image processing circuit 124. During focus detection processing using the contrast detection method, the focus lens 104 is moved and the focus lens position where the evaluation value (focus evaluation value) reaches its peak is detected as the in-focus position.

In this way, the imaging device 10 of the present embodiment can perform the imaging plane phase difference AF and TVAF in combination, and depending on the situation, these can be used selectively or in combination. can. The phase difference AF unit 129 and the TVAF unit 130 function as a focus control unit that controls the position of the focus lens 104 using the respective focus detection results.

(Image sensor)
Next, the pixel arrangement of the image sensor 122 in this embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic diagram of the arrangement of pixels (imaging pixels and focus detection pixels) of the image sensor 122. In FIG. 2, the pixel (imaging pixel) array of the image sensor (two-dimensional CMOS sensor element) 122 of this embodiment is shown in a range of 4 columns x 4 rows, and the focus detection pixel array is shown in a range of 8 columns x 4 rows. In this example, in the pixel group 200 of 2 columns x 2 rows shown in FIG. A pixel 200B having a spectral sensitivity of B (blue) is arranged at the lower left and at the lower right. Further, each pixel includes a first focus detection pixel (first pixel) 201 and a second focus detection pixel (second pixel) 202 arranged in two columns and one row.

A large number of 4 columns x 4 rows of pixels (8 columns x 4 rows of focus detection pixels) shown in FIG. 2 are arranged on a surface to enable acquisition of a captured image (focus detection signal). In this example, the pixel period P is 4 μm, the number of pixels N is 5575 horizontal columns × 3725 vertical rows = approximately 20.75 million pixels, the column direction period PAF of focus detection pixels is 2 μm, and the number of focus detection pixels NAF is 11150 horizontal columns × The explanation will be given assuming that the image sensor has 3725 vertical lines = approximately 41.5 million pixels.

FIG. 3 is a schematic plan view and a schematic cross-sectional view of pixels of the image sensor 122. 3(a) is a plan view of one pixel 200G of the image sensor 122 shown in FIG. 2, viewed from the light-receiving surface side (+z side) of the image sensor 122, and FIG. 3(b) is a plan view of one pixel 200G of the image sensor 122 shown in FIG. A cross-sectional view of the a-a cross section viewed from the -y side is shown.

As shown in FIG. 3, in the pixel 200G of this example, a microlens 305 is formed to condense incident light on the light receiving side of each pixel, and NH division (division into two) is performed in the x direction, and NH division is performed in the y direction. A photoelectric conversion section 301 and a photoelectric conversion section 302 which are divided into NV (divided into one) are formed. A photoelectric conversion unit 301 and a photoelectric conversion unit 302 correspond to the first focus detection pixel 201 and the second focus detection pixel 202, respectively.

The photoelectric conversion unit 301 and the photoelectric conversion unit 302 may be a pin structure photodiode in which an intrinsic layer is sandwiched between a p-type layer and an n-type layer, or if necessary, the intrinsic layer may be omitted and a pn junction It can also be used as a photodiode. In each pixel, a color filter 306 is formed between the microlens 305 and the photoelectric conversion section 301 and the photoelectric conversion section 302. Furthermore, if necessary, the spectral transmittance of the color filter 306 may be changed for each subpixel, or the color filter 306 may be omitted.

The light incident on the pixel 200G shown in FIG. 3 is collected by the microlens 305, separated by the color filter 306, and then received by the photoelectric conversion unit 301 and the photoelectric conversion unit 302. In the photoelectric conversion unit 301 and the photoelectric conversion unit 302, pairs of electrons and holes are generated depending on the amount of light received, and after being separated by a depletion layer, negatively charged electrons are accumulated in an n-type layer (not shown). Holes are discharged to the outside of the image sensor through a p-type layer connected to a constant voltage source (not shown). Electrons accumulated in the n-type layers (not shown) of the photoelectric conversion section 301 and the photoelectric conversion section 302 are transferred to a capacitance section (FD) via a transfer gate and converted into a voltage signal.

Next, with reference to FIG. 4, the correspondence between the pixel structure of the image sensor 122 of the present embodiment shown in FIG. 3 and pupil division will be described. FIG. 4 is a schematic explanatory diagram of pixels and pupil division of the image sensor 122, and is a cross-sectional view of the a-a cross section of the pixel structure of the present embodiment shown in FIG. shows the pupil plane (pupil distance Ds) of In FIG. 4, the x-axis and y-axis of the cross-sectional view are reversed with respect to FIG. 3 in order to correspond to the coordinate axes of the pupil plane of the image sensor 122.

In FIG. 4, the first pupil partial region 501 of the first focus detection pixel 201 has an approximately conjugate relationship with the light receiving surface of the photoelectric conversion unit 301 whose center of gravity is eccentric in the −x direction due to the microlens 305. It represents the pupil area where light can be received by the single focus detection pixel 201. The first pupil partial region 501 of the first focus detection pixel 201 has a center of gravity eccentric to the +X side on the pupil plane. In FIG. 4, the second pupil partial region 502 of the second focus detection pixel 202 has an approximately conjugate relationship with the light receiving surface of the photoelectric conversion unit 302 whose center of gravity is eccentric in the +x direction due to the microlens 305. It represents the pupil area where the focus detection pixel 202 can receive light. The center of gravity of the second pupil partial region 502 of the second focus detection pixel 202 is eccentric to the −X side on the pupil plane. Further, in FIG. 4, the pupil area 500 is the pupil area where light can be received by the entire pixel 200G when the photoelectric conversion unit 301 and the photoelectric conversion unit 302 (the first focus detection pixel 201 and the second focus detection pixel 202) are all combined. be.

In imaging plane phase difference AF, the microlens 305 of the imaging element 122 is used to divide the pupil, so it is affected by diffraction. In FIG. 4, the pupil distance to the pupil plane of the image sensor 122 is several tens of mm, while the diameter of the microlens 305 is several μm. For this reason, the aperture value of the microlens 305 is in the tens of thousands, and diffraction blur on the order of tens of millimeters occurs. Therefore, the image of the light-receiving surface of the photoelectric conversion unit does not represent a clear pupil region or pupil partial region, but a light-receiving sensitivity characteristic (incident angle distribution of light-receiving rate).

Next, with reference to FIG. 5, the correspondence between the image sensor 122 and pupil divisions will be described. FIG. 5 is a schematic diagram of the image sensor 122 and pupil division. The light fluxes that have passed through different pupil partial areas, the first pupil partial area 501 and the second pupil partial area 502, enter each pixel of the image sensor 122 at different angles, and are divided into 2×1 for first focus detection. The light is received by the pixel 201 and the second focus detection pixel 202. This embodiment is an example in which the pupil area is divided into two pupils in the horizontal direction. If necessary, pupil division may be performed in the vertical direction. Further, pupil division may be performed both in the horizontal direction and in the vertical direction.

In the image sensor 122 of this embodiment, a plurality of image sensors including a first focus detection pixel 201 and a second focus detection pixel 202 are arranged. The first focus detection pixel 201 receives a light beam passing through the first pupil partial region 501 of the imaging optical system. The second focus detection pixel 202 receives a light flux that passes through a second pupil partial area 502 of the imaging optical system, which is different from the first pupil partial area 501 . Further, the imaging pixel receives a light flux that passes through a pupil region 500 that is a combination of a first pupil partial region 501 and a second pupil partial region 502 of the imaging optical system.

In the image sensor 122 of this embodiment, each image sensor is composed of a first focus detection pixel 201 and a second focus detection pixel 202. If necessary, the imaging pixel, the first focus detection pixel 201, and the second focus detection pixel 202 are made into individual pixel configurations, and the first focus detection pixel 2001 and the second focus detection pixel 202 are formed as part of the imaging pixel array. It may also be configured to be partially arranged.

In this embodiment, the light reception signals of the first focus detection pixel 201 of each pixel of the image sensor 122 are collected to generate the first focus signal, and the light reception signals of the second focus detection pixel 202 of each pixel are collected to generate the second focus signal. Generates a signal and performs focus detection. Furthermore, by adding the signal from the first focus detection pixel 201 (first focus detection signal) and the signal from the second focus detection pixel 202 (second focus detection signal) for each pixel of the image sensor 122, An imaging signal (captured image) with a resolution of N effective pixels is generated. Note that the method of generating each signal is not limited to the embodiment described in this example. For example, the second focus signal may be generated from the difference between the imaging signal and the first focus signal.

(Relationship between defocus amount and image shift amount)
Next, with reference to FIG. 6, the relationship between the defocus amount and the image shift amount of the first focus detection signal and the second focus detection signal acquired by the image sensor 122 will be described. FIG. 6 is a schematic relationship diagram between the defocus amount of the first focus detection signal and the second focus detection signal and the image shift amount between the first focus detection signal and the second focus detection signal. The image sensor 122 is arranged on the image sensor 800, and the pupil plane of the image sensor 122 is divided into two into a first pupil partial area 501 and a second pupil partial area 502, similar to FIGS. 4 and 5.

The defocus amount d is defined as the distance from the subject's imaging position to the imaging plane as size |d|, and the front focus state where the subject's imaging position is closer to the subject than the imaging plane is defined as a negative sign (d<0). defined. Further, a back focus state in which the imaging position of the subject is on the opposite side of the subject from the imaging plane is defined as a positive sign (d>0). In a focused state where the imaging position of the subject is on the imaging plane (focusing position), d=0. In FIG. 6, a subject 801 shows an example of an in-focus state (d=0), and a subject 802 shows an example of a front-focus state (d<0). The front focus state (d<0) and the back focus state (d>0) are combined to form a defocus state (|d|>0).

In the front focus state (d<0), among the light fluxes from the subject 802, the light fluxes that have passed through the first pupil partial area 501 (second pupil partial area 502) are once condensed and then moved to the center of gravity G1 of the light beams. (G2) as the center and spreads to a width Γ1 (Γ2), resulting in a blurred image on the imaging surface 800. The blurred image is received by the first focus detection pixel 201 (second focus detection pixel 202) that constitutes each pixel arranged in the image sensor 122, and a first focus detection signal (second focus detection signal) is generated. Ru. Therefore, the first focus detection signal (second focus detection signal) is recorded as a subject image in which the subject 802 is blurred to a width Γ1 (Γ2) at the center of gravity position G1 (G2) on the imaging surface 800. The blur width Γ1 (Γ2) of the subject image generally increases in proportion as the magnitude |d| of the defocus amount d increases. Similarly, the magnitude |p| of the image shift amount p of the subject image between the first focus detection signal and the second focus detection signal (=difference G1-G2 in the center of gravity position of the luminous flux) is also equal to the defocus amount d. As the magnitude |d| increases, it generally increases proportionally. The same is true in the rear focus state (d>0), although the direction of image shift of the subject image between the first focus detection signal and the second focus detection signal is opposite to that in the front focus state.

Therefore, in this embodiment, even though the magnitude of the defocus amount of the first focus detection signal and the second focus detection signal or the imaging signal obtained by adding the first focus detection signal and the second focus detection signal increases, Accordingly, the amount of image shift between the first focus detection signal and the second focus detection signal increases. As the amount of defocus of the imaging signal increases, the amount of image shift between the first focus detection signal and the second focus detection signal increases. Based on this relationship, focus detection is performed by converting the image shift amount into a detected defocus amount using a conversion coefficient (defocus conversion coefficient) calculated based on the base line length.

(baseline length)
Next, the base line length will be explained with reference to FIGS. 7(a) and 7(b). The base line length is calculated based on the difference in the center of gravity of the light receiving sensitivity characteristics of the first focus detection pixel 201 and the second focus detection pixel 202. FIGS. 7(a) and 7(b) are schematic explanatory diagrams of the base line length when there is no transmittance distribution layer, and FIG. 7(a) is the aperture at the center image height, and FIG. 7(b) is the aperture at the peripheral image height. , the light-receiving sensitivity characteristics, and the baseline length.

At the center image height, as shown in FIG. 7(a), the light flux that can be received is defined by the aperture 102, which is one of the aperture information. Therefore, of the first light receiving sensitivity characteristic 701 which is the light receiving sensitivity characteristic of the first focus detection pixel 201 and the second light receiving sensitivity characteristic 702 which is the light receiving sensitivity characteristic of the second focus detection pixel 202, the area where light can be received is the aperture. This is the inner area of 102. Therefore, the difference in the center of gravity between the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702, that is, the base line length is BL711.

On the other hand, at the peripheral image height, as shown in FIG. 7(b), there is an underlined frame 401 that is one of the aperture information that defines the luminous flux on the x<0 side, and aperture information that defines the luminous flux on the x>0 side. An overlined frame 402, which is one of the above, defines the light flux that can be received. Therefore, the area where light can be received among the first light receiving sensitivity characteristic and the second light receiving sensitivity characteristic is the area surrounded by the underlined frame 401 and the overlined frame 402, and the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702 are The difference in the center of gravity, that is, the base line length is BL712.

In this way, the baseline length is determined based on the light-receiving sensitivity characteristics and the aperture information that defines the light-receiving area, and these pieces of information are required to calculate the accurate baseline length.

(Transmittance distribution)
Next, the transmittance distribution layer 105 will be described with reference to FIG. 8. FIG. 8 is a schematic explanatory diagram of the transmittance distribution layer 105. The transmittance distribution 810 at the pupil distance Ds by the transmittance distribution layer 105 has a peak at the center of the optical axis and decreases as the distance from the optical axis increases. By arranging such a transmittance distribution, the edges of the blurred image can be smoothed, and it is possible to achieve a blur depiction that cannot be obtained with a normal optical system, thereby expanding the expressive range of photography.

However, since the transmittance distribution is no longer uniform, the base line length is determined by multiplying the light receiving sensitivity characteristic of the first focus detection pixel 201 or the second focus detection pixel 202 by the transmittance distribution of the transmittance distribution layer 105. Determined by state. Therefore, the base line length needs to be calculated in consideration of the transmittance distribution. Therefore, in this example, the influence of the transmittance distribution is taken into account by holding aperture information that corresponds to changes in the base line length due to the transmittance distribution, and the baseline length is It is possible to calculate

(Baseline length and transmittance distribution)
Next, the base line length when the transmittance distribution layer 105 is present will be described with reference to FIGS. 9(a) and 9(b). 9(a) and 9(b) are schematic explanatory diagrams of the base line length when there is the transmittance distribution layer 105, and FIG. 9(a) is for the central image height, and FIG. 9(b) is for the peripheral image height. The aperture, light-receiving sensitivity characteristics, and baseline length are shown.

The third light receiving sensitivity characteristic 901 and the fourth light receiving sensitivity characteristic 902 are light receiving sensitivity characteristics obtained by multiplying each of the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702 by the transmittance distribution 810. The third light receiving sensitivity characteristic 901 and the fourth light receiving sensitivity characteristic 902 have lower light receiving sensitivity as they move away from the optical axis than the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702, respectively, according to the characteristics of the transmittance distribution 810. It has become. Therefore, the base line length BL911 when the transmittance distribution layer 105 is present is shorter than the base line length BL711 when the transmittance distribution layer 105 is not present. The base line length BL912 of the peripheral image height is also shorter than the base line length BL712 when the transmittance distribution layer 105 is not provided. However, since the shape of the aperture and the transmittance distribution are different from those at the central image height, the rate of change at the peripheral image height is different from that at the central image height.

(Aperture information indicating baseline length considering transmittance distribution)
In order to calculate the baseline length with the same behavior as an imaging optical system that does not have the transmittance distribution layer 105, it is necessary to maintain aperture information that takes into account the influence of the transmittance distribution, corresponding to the change in the baseline length due to the transmittance distribution. There is.

Next, aperture information (first aperture information) indicating a baseline length in consideration of the influence of transmittance distribution will be described with reference to FIGS. 10(a) and 10(b). FIG. 10 is a schematic explanatory diagram of the first aperture information, in which FIG. 10(a) shows the aperture information indicating the base line length in consideration of the transmittance distribution at the central image height and FIG. 10(b) in consideration of the transmittance distribution at the peripheral image height.

As shown in FIG. 10A, the long baseline aperture frame 1000 is a long baseline aperture frame (first aperture information for the central image height) that indicates a baseline length that takes into account the transmittance distribution at the central image height. The long baseline aperture frame 1000 is configured such that the baseline length for the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702 without the transmittance distribution layer 105 is equal to the baseline length BL911 when the transmittance distribution layer 105 is present. In this case, the diameter of the aperture 102 is changed. The long baseline aperture frame 1000 has a smaller diameter than the aperture 102 in consideration of the fact that the baseline length is shortened due to the transmittance distribution. By retaining and using the baseline long aperture frame 1000 as first aperture information, it becomes possible to calculate the baseline length with the same behavior as an imaging optical system that does not have the transmittance distribution layer 105.

As shown in FIG. 10B, a base line length underlined frame 1001 on the x<0 side and a base line length overlined frame 1002 on the x>0 side indicate the base line length in consideration of the transmittance distribution of the peripheral image height. These are set in the underlined box so that the baseline length for the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702 without the transmittance distribution layer 105 is equal to the baseline length BL912 in the case where the transmittance distribution layer 105 is present. 401 and the center position of the overlined frame 402 are changed. The method of changing the center position is to change it so that the distance between the transmittance distribution center (transmittance distribution peak position) and the baseline length underlined frame 1001 is equal to the distance between the transmittance distribution center and the baseline length overlined frame 1002. There is. When the distances to the transmittance distribution centers are made equal, if either the base length underline frame 1001 or the base line length upper line frame 1002 is located outside the underline frame 401 or the overline frame 402, only the center position of the one that is not outside is set. change.

In this embodiment, the base line length underline frame 1001 and the base line length upper line frame 1002 are calculated by changing the center positions of the underline frame 401 and the overline frame 402, but they may be calculated by changing the diameter instead of the center position. . The base line length underline frame 1001 and the base line length upper line frame 1002 are located inside the underline frame 401 and the upper line frame 402 in consideration of the fact that the base line length is shortened due to the transmittance distribution. By retaining and using the baseline length underlined frame 1001 and the baseline length overlined frame 1002 as first aperture information, it becomes possible to calculate the baseline length with the same behavior as a lens without a transmittance distribution layer.

(Processing flow)
Next, with reference to FIG. 11, aperture information acquisition in this embodiment will be described. FIG. 11 is a flowchart of aperture information acquisition (communication method) in this embodiment. Each step in FIG. 11 is mainly executed by the lens MPU 117.

First, in step S1101, the lens MPU 117 acquires the current zoom state of the lens unit 100. Subsequently, in step S1102, the lens MPU 117 acquires the current focus state of the lens unit 100. Subsequently, in step S1103, the lens MPU 117 acquires image height information designated by the camera MPU 125 through communication via the mount M. Subsequently, in step S1104, the lens MPU 117 obtains the current set aperture value.

Subsequently, in step S1105, the lens MPU 117 determines whether the first aperture information can be acquired. In order to reduce memory capacity, the lens memory 118 stores first aperture information only in a range below a predetermined aperture value. In the transmittance distribution 810, the transmittance decreases as the distance from the optical axis increases, and the difference in transmittance from the center of the optical axis increases. Therefore, the more regions farther from the optical axis are included, the greater the influence on the baseline length. Conversely, in the case of only a region near the center of the optical axis, the difference in transmittance from the center of the optical axis is small, so the influence on the baseline length is small. Therefore, when the aperture value is large, the aperture diameter becomes small and only the area near the center of the optical axis is covered, so that the influence of the transmittance distribution on the baseline length becomes small.

From the above, when the aperture value is large, the influence on the baseline length becomes small. Therefore, in order to reduce memory capacity, the range of aperture values for which the first aperture information is held is limited to a range smaller than a predetermined aperture value. Therefore, in this embodiment, if the lens memory 118 holds the first aperture information in step S1105 (if the current aperture value is smaller than the predetermined aperture value), the lens MPU 117 can acquire the first aperture information. It is determined that there is, and the process advances to step S1106. On the other hand, if the lens memory 118 does not hold the first aperture information in step S1105 (if the current aperture value is larger than the predetermined aperture value), step S1106 is skipped, and the lens MPU 117 acquires the first aperture information. The process advances to step S1107 without doing so. Note that in this embodiment, in order to reduce memory capacity, the range in which the first aperture information is held in the lens memory 118 is limited, but the first aperture information is held in the entire range of settable aperture values, The process may always proceed to step S1106 to obtain the first aperture information.

In step S1106, the lens MPU 117 obtains first aperture information corresponding to the zoom state, focus state, image height, and set aperture value obtained in steps S1101 to S1104 from the lens memory 118. The lens memory 118 is stored for each zoom state in which the zoom range is divided into a plurality of parts, for each focus state in which the focus range is divided into a plurality of parts, for each image height in which the image height range is divided into a plurality of parts, and for each image height in which the predetermined aperture value range is divided into a plurality of parts. First aperture information is stored for each aperture value. Therefore, the current zoom state, focus state, aperture value, and first aperture information at the image height specified by the camera MPU 125 are calculated and obtained by linear interpolation from the first aperture information of neighboring states. In this embodiment, the current zoom state, focus state, aperture value, and first aperture information of the image height specified by the camera MPU 125 are obtained by calculating by linear interpolation. 1 aperture information may be acquired.

Subsequently, in step S1107, the lens MPU 117 acquires second aperture information. The second aperture information is aperture information indicating the amount of light, and is aperture information calculated in consideration of light attenuation due to the transmittance distribution 810. As described with reference to FIG. 10, the first aperture information is aperture information indicating the baseline length in consideration of the influence of the transmittance distribution. Similarly, the aperture information indicating the amount of light (second aperture information) is aperture information in which the aperture 102, the underlined frame 401, and the overlined frame 402 are changed in consideration of light attenuation due to the transmittance distribution. In this embodiment, the second aperture information is calculated for the underlined frame and the overlined frame based on the peripheral image height and stored in the lens memory 118, but it is regarded as one frame with the same amount of light, and only one frame information is used. may be held as the second aperture information. Further, in this embodiment, the second aperture information has been described as aperture information indicating the amount of light, but it may be aperture information indicating depth in consideration of the influence of the transmittance distribution 810 on the depth. Further, the second aperture information may be information regarding an aperture value (aperture diameter). In that case, the information on the set aperture value acquired in step S1104 may be used as the second aperture information, and the process in step S1107 may be skipped.

Subsequently, in step S1108, the lens MPU 117 transmits the aperture information to the camera MPU 125, and ends this flow. That is, when the lens MPU 117 determines in step S1105 that the first aperture information can be acquired, the lens MPU 117 transmits the first aperture information and the second aperture information to the camera MPU 125. On the other hand, if the lens MPU 117 determines in step S1105 that the first aperture information cannot be acquired, it transmits the second aperture information to the camera MPU 125.

In this embodiment, the lens MPU 117 acquires the first aperture information according to the image height and transmits it to the camera MPU 125, but the invention is not limited to this. For example, the lens MPU 117 may transmit the first aperture information of the entire image height to the camera MPU 125, and the camera MPU 125 may acquire the first aperture information according to the image height. The same applies to the zoom state, focus state, or set aperture value.

In addition, in this embodiment, the aperture value range is divided into multiple parts and held, and calculation is performed by linear interpolation, but the first aperture information is held as a function of the aperture value, and the first aperture information is calculated as a function according to the obtained aperture value. It may be calculated by This also applies to the zoom state, focus state, or image height.

Further, in this embodiment, only the first aperture information calculated based on the specific first light-receiving sensitivity characteristic and second light-receiving sensitivity characteristic is held, but the present invention is not limited to this. For example, even if the first aperture information calculated based on the first light-receiving sensitivity characteristic and the second light-receiving sensitivity characteristic of multiple patterns with different characteristics is held, and the first aperture information is acquired based on the characteristics of the image sensor 122, good.

Next, Example 2 of the present invention will be described. This embodiment differs from the first embodiment with respect to the location where the aperture information is acquired and the use of the aperture information after acquisition. Note that the other configurations and operations in this example are the same as in Example 1, so their descriptions will be omitted.

In the first embodiment, the lens MPU 117 acquires the first aperture information and the second aperture information stored in the lens memory 118 of the lens unit 100 and transmits them to the camera MPU 125. On the other hand, in this embodiment, the camera MPU 125 acquires the first aperture information and the second aperture information stored in the memory 128 of the camera body 120, and calculates the defocus conversion coefficient using the first aperture information.

(Processing flow)
Hereinafter, with reference to FIG. 12, calculation of the defocus conversion coefficient in this embodiment will be described. FIG. 12 is a flowchart of defocus conversion coefficient calculation (communication method) in this embodiment. Note that each step in FIG. 12 is mainly executed by the camera MPU 125.

First, in step S1201, the camera MPU 125 acquires the current zoom state of the lens unit 100 from the lens MPU 117 through communication via the mount M. Subsequently, in step S1202, the camera MPU 125 acquires the current focus state of the lens unit 100 from the lens MPU 117 through communication via the mount M. Subsequently, in step S1203, the camera MPU 125 acquires image height information for performing defocus calculation. Subsequently, in step S1204, the camera MPU 125 acquires the current set aperture value from the lens MPU 117 through communication via the mount M.

Subsequently, in step S1205, the camera MPU 125 acquires the lens identification number (lens information such as lens ID) of the lens unit 100 from the lens MPU 117 through communication via the mount M. The memory 128 stores first aperture information and second aperture information for each lens identification number (for each lens unit). That is, the memory 128 holds first aperture information and second aperture information calculated in the same manner as in the first embodiment regarding the lens unit having the transmittance distribution layer 105. On the other hand, for a lens unit that does not have the transmittance distribution layer 105, the first aperture information and the second aperture information are the same, so the memory 128 does not hold the first aperture information and only stores the second aperture information. keeping.

Subsequently, in step S1206, the camera MPU 125 (obtaining means 129a) obtains the zoom state, focus state, image height, set aperture value, and first aperture information corresponding to the lens identification number obtained in steps S1201 to S1205. do. When acquiring the lens identification number of a lens unit that does not have the transmittance distribution layer 105, the camera MPU 125 acquires the second aperture information as the first aperture information. The memory 128 stores information for each lens identification number, each zoom state in which the zoom range is divided into a plurality of parts, each focus state in which the focus range is divided into a plurality of parts, each image height in which the image height range is divided into a plurality of parts, and a plurality of predetermined aperture value ranges. First aperture information is stored for each aperture value divided into. For this reason, the camera MPU 125 linearly interpolates the lens identification number, current zoom state, focus state, set aperture value, and first aperture information at the image height for defocus calculation from the first aperture information of neighboring states. Calculate and obtain.

Subsequently, in step S1207, the camera MPU 125 retrieves from the memory 128 a coefficient (coefficient m000 of a function for calculating the baseline length BL expressed by the following formula (1)) according to the set aperture value acquired in step S1204. ~m220). The coefficients acquired here are for the image height information h acquired in step S1203, the distance b1 between the overlined frame and the aperture center of the first aperture information acquired in step S1206, and the distance b2 between the underlined frame and the aperture center. It is a coefficient of a quadratic function. In this embodiment, coefficients in a quadratic function regarding the image height information h and distances b1 and b2 are obtained, but the coefficients are not limited to quadratic functions, and may be linear functions or functions of three or more. You can. Alternatively, the order may be made different for each variable by decreasing the order for variables with small changes and increasing the order for variables with large changes.

Subsequently, in step S1208, the camera MPU 125 (calculating means 129b) calculates a defocus conversion coefficient K for converting the image shift amount into a defocus amount. That is, the camera MPU 125 calculates the following equations (1) and (2) based on the image height information obtained in step S1203, the first aperture information obtained in step S1206, and the coefficient obtained in step S1207. The defocus conversion coefficient K is calculated using the defocus conversion coefficient K.

After completing step S1208, the camera MPU 125 ends the process of calculating the defocus conversion coefficient. Then, the camera MPU 125 calculates the defocus amount by multiplying the image shift amount calculated by the correlation calculation for the pair of image signals from the image sensor 122 by the defocus conversion coefficient K calculated according to the flowchart of FIG. Then, the camera MPU 125 and the lens MPU 117 perform focus control (AF control) based on the calculated defocus amount.

Next, Example 3 of the present invention will be described. This embodiment differs from the first embodiment in that a detachable unit (converter lens unit) is attached between the lens unit 100 and the camera body 120. In this embodiment, the third aperture information indicating the baseline length with the removable unit stored in advance is acquired, and the fourth aperture information is calculated from the optical information of the removable unit and the second aperture information. A case where aperture information is acquired will be explained. Note that the other configurations and operations in this example are the same as in Example 1, so their descriptions will be omitted.

First, with reference to FIG. 13, the configuration of the imaging device in this example will be described. FIG. 13 is a block diagram of the imaging device 10a in this embodiment. The imaging device 10a includes a lens unit (interchangeable lens, lens device) 100, a camera body (imaging device body) 120, and a detachable unit (converter lens unit 600) between the lens unit 100 and the camera body 120. It is a camera system. Converter lens unit 600 is detachably attached to camera body 120 via mount M, and detachably attached to lens unit 100 via mount M2. In addition, the same reference numerals are given to the same structure as FIG. 1, and description is abbreviate|omitted. Further, in this embodiment, the converter lens unit 600 is a unit that can be attached and detached between the lens unit 100 and the camera body 120, but the unit is not limited to this.

In FIG. 13, a converter lens unit 600 is a photographic lens that includes a converter lens 601 and a converter memory 602, and changes the focal length of the lens unit 100 that forms an optical image of a subject. Note that in the following description, the lens unit 100 will be referred to as a "master lens 100" to distinguish it from the converter lens 601. When the converter lens unit 600 is attached, the first lens group 101, the second lens group 103, and the converter lens 601 realize a zoom function. Converter memory 602 stores in advance optical information (aperture information) necessary for automatic focus adjustment. Lens MPU 117 is configured to be able to acquire optical information (aperture information) stored in converter memory 602.

(Processing flow)
Next, with reference to FIG. 14, aperture information acquisition in this embodiment will be described. FIG. 14 is a flowchart of aperture information acquisition (communication method) in this embodiment. Each step in FIG. 14 is mainly executed by the lens MPU 117.

First, in step S1401, the lens MPU 117 obtains the current zoom state of the lens unit 100. Subsequently, in step S1402, the lens MPU 117 obtains the current focus state of the lens unit 100. Subsequently, in step S1403, the lens MPU 117 acquires image height information designated by the camera MPU 125 through communication via the mounts M and M2. Subsequently, in step S1404, the lens MPU 117 obtains the current set aperture value. Subsequently, in step S1405, the lens MPU 117 acquires second aperture information. In this embodiment, the second aperture information is information regarding the aperture value (aperture diameter).

Subsequently, in step S1406, the lens MPU 117 determines whether the converter lens unit (removable unit) 600 is attached. If it is determined in step S1406 that the converter lens unit 600 is attached, the process advances to step S1407.

In step S1407, the lens MPU 117 acquires optical information of the converter lens unit 600 from the converter lens unit 600. In this embodiment, the optical information is the focal length magnification of the converter lens unit 600.

Subsequently, in step S1408, the lens MPU 117 acquires the acquired zoom state, focus state, image height, and third aperture information according to the set aperture value. The lens memory 118 is stored for each zoom state in which the zoom range is divided into a plurality of parts, for each focus state in which the focus range is divided into a plurality of parts, for each image height in which the image height range is divided into a plurality of parts, and for each image height in which the predetermined aperture value range is divided into a plurality of parts. Third aperture information is stored for each aperture value. Therefore, the lens MPU 117 calculates the current zoom state, focus state, set aperture value, and third aperture information at the image height specified by the camera MPU 125 by linearly interpolating the third aperture information of neighboring states. get. In this embodiment, the current zoom state, focus state, aperture value, and third aperture information of the image height specified by the camera MPU 125 are obtained by calculating by linear interpolation. 3 aperture information may be acquired.

Subsequently, in step S1409, the lens MPU 117 calculates fourth aperture information based on the acquired second aperture information and the optical information of the converter lens unit 600. The fourth aperture information is information regarding the aperture value (aperture diameter) when the converter lens unit 600 is attached. The aperture value when the converter lens unit 600 is attached is proportional to the focal length magnification of the converter lens unit 600. Therefore, it is possible to calculate the fourth aperture information based on the acquired second aperture information and the optical information of the converter lens unit 600. In this embodiment, the fourth aperture information is calculated using the focal length magnification as the optical information of the converter lens 601, but the fourth aperture information may be calculated using optical information other than the focal length magnification.

Here, the third aperture information and the fourth aperture information will be explained with reference to FIG. 15. FIG. 15 is a schematic explanatory diagram of the third aperture information and the fourth aperture information. FIG. 15A is a schematic explanatory diagram of the transmittance distribution layer 105 with the converter lens unit 600 attached. With the converter lens unit 600 attached, the transmittance distribution layer 105 is located further away from the light receiving surface than in the case of FIG. 8 where the converter lens unit 600 is not attached. Therefore, the transmittance distribution 811 at the pupil distance Ds by the transmittance distribution layer 105 is distributed as if the transmittance distribution 810 in FIG. 8 is reduced.

FIG. 15(b) is a schematic explanatory diagram of the base line length and fourth aperture information when the converter lens unit 600 is attached. The fifth light-receiving sensitivity characteristic 1501 and the sixth light-receiving sensitivity characteristic 1502 indicate the light-receiving sensitivity characteristic obtained by multiplying each of the first light-receiving sensitivity characteristic 701 and the second light-receiving sensitivity characteristic 702 by the transmittance distribution 811. The base line length BL1511 is the base line length for the fifth light receiving sensitivity characteristic 1501 and the sixth light receiving sensitivity characteristic 1502 in a state where the converter lens unit 600 is attached, according to the characteristics of the transmittance distribution 811. The base line length BL1511 is shorter than the base line length BL911 for the third light receiving sensitivity characteristic 901 and the fourth light receiving sensitivity characteristic 902 in a state where the converter lens unit 600 is not attached.

Further, the aperture 102 in a state where the converter lens unit 600 is attached is located further away from the light receiving surface than in the state shown in FIG. 9A where the converter lens unit 600 is not attached. Therefore, the diameter of the aperture 102 at the pupil distance Ds is smaller than the diameter of the aperture 102 at the pupil distance Ds in FIG. 9A where the converter lens unit 600 is not attached.

FIG. 15C is a schematic explanatory diagram of aperture information (third aperture information) indicating the base line length in consideration of the transmittance distribution layer 105 in a state where the converter lens unit 600 is attached. A baseline long aperture frame 1510 (third aperture information) indicating a baseline length in consideration of the transmittance distribution with the converter lens unit 600 attached is obtained by changing the diameter of the aperture 102. That is, in the baseline long aperture frame 1510, the baseline length for the first light receiving sensitivity characteristic 701 and the second light receiving sensitivity characteristic 702 without the transmittance distribution layer 105 is equal to the baseline length BL1511 in the case where the transmittance distribution layer 105 is present. The diameter of the diaphragm 102 is changed so that the diameter of the diaphragm 102 is changed. The baseline long aperture frame 1510 has a smaller diameter than the aperture 102 in consideration of the fact that the baseline length is shortened due to the transmittance distribution. By retaining and using the baseline long aperture frame 1510 as the third aperture information, it becomes possible to calculate the baseline length with the same behavior as the lens unit 100 that does not have the transmittance distribution layer 105.

Subsequently, in step S1410 of FIG. 14, the lens MPU 117 transmits the third aperture information and the fourth aperture information to the camera MPU 125 through communication via the mounts M and M2. After completing step S1410, the lens MPU 117 ends the aperture information acquisition process.

Next, a case will be described in which it is determined in step S1406 that the converter lens unit 600 is not attached. If it is determined in step S1406 that converter lens unit 600 is not attached, the process advances to step S1411.

In step S1411, the lens MPU 117 acquires the acquired zoom state, focus state, image height, and first aperture information according to the set aperture value. The lens memory 118 stores information for each zoom state in which the zoom range is divided into a plurality of parts, for each focus state in which the focus range is divided into a plurality of parts, for each image height in which the image height range is divided into a plurality of parts, and for each aperture value in which a predetermined aperture value range is divided into a plurality of parts. The first aperture information is stored for each time. Therefore, the lens MPU 117 calculates and obtains the first aperture information at the current zoom state, focus state, aperture value, and image height specified by the camera MPU 125 by linear interpolation from the first aperture information of neighboring states. In this embodiment, the current zoom state, focus state, aperture value, and first aperture information of the image height specified by the camera MPU 125 are calculated and acquired by linear interpolation, but the lens MPU 117 calculates and obtains the first aperture information of the current zoom state, focus state, aperture value, and image height specified by the camera MPU 125. First aperture information may be acquired.

Subsequently, in step S1412, the lens MPU 117 transmits the first aperture information and the second aperture information to the camera MPU 125 through communication via the mounts M and M2. Upon completion of step S1412, the aperture information acquisition process ends.

In this embodiment, the lens MPU 117 acquires first aperture information and third aperture information according to the acquired image height, and transmits the acquired information to the camera MPU 125. However, the present embodiment is not limited to this, and the first aperture information and the third aperture information for all image heights are sent together to the camera MPU 125, and the camera MPU 125 The first aperture information and the third aperture information may be acquired. The same applies to the zoom state, focus state, or set aperture value.

In this example, the aperture value range is divided into a plurality of parts and held, and the calculation is performed by linear interpolation. However, the first aperture information and the third aperture information are held as a function of the aperture value, and the aperture value range is It may also be calculated using a function. This also applies to the zoom state, focus state, or image height.

In this embodiment, only the first aperture information and the third aperture information calculated based on the specific first light-receiving sensitivity characteristic and second light-receiving sensitivity characteristic are held in the lens memory 118, but the invention is not limited to this. do not have. The lens memory 118 holds first aperture information and third aperture information calculated based on a plurality of patterns of first light-receiving sensitivity characteristics and second light-receiving sensitivity characteristics having different characteristics, and the lens MPU 117 stores first aperture information and third aperture information calculated based on a plurality of patterns of first light-receiving sensitivity characteristics and second light-receiving sensitivity characteristics having different characteristics. The first aperture information may be acquired according to the following.

(Other examples)
The present invention provides a system or device with a program that implements one or more of the functions of the above-described embodiments via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

As described above, in each embodiment, the lens device (lens unit 100) is removably attached to the imaging device (camera body 120), and includes the imaging optical system, storage means (lens memory 118), and communication means (lens memory 118). MPU 117). The imaging optical system has a transmittance distribution layer 105 that is rotationally symmetrical about the optical axis. The storage means stores aperture information of the imaging optical system. The communication means transmits the aperture information to the imaging device. Further, the aperture information includes first aperture information regarding the baseline length of the imaging optical system having the transmittance distribution layer.

Preferably, the communication means transmits first aperture information corresponding to at least one of a zoom state, a focus state, or an aperture value of the imaging optical system, out of the first aperture information stored in the storage means, to the imaging device. do. Preferably, the aperture information includes second aperture information regarding at least one of the aperture value, the amount of light, and the depth. Preferably, the baseline length is based on the light receiving sensitivity characteristics of the first pixel (first focus detection pixel 201) and the second pixel (second focus detection pixel 202) of the image sensor 122, and the transmittance distribution of the transmittance distribution layer. , determined based on.

Preferably, the first aperture information is determined based on at least one of the outer edge of the aperture of the imaging optical system or the outer edge of the aperture of the imaging optical system, and the transmittance distribution of the transmittance distribution layer. More preferably, the aperture area based on the first aperture information is smaller than each of the area surrounded by the outer edge of the aperture and the area surrounded by the outer edge of the aperture. Preferably, the difference between the aperture area based on the aperture information and the area surrounded by the outer edge of the aperture or the area surrounded by the outer edge of the aperture becomes smaller as the diameter of the outer edge of the aperture becomes smaller. Preferably, the communication means does not transmit the first aperture information to the imaging device when the diameter of the outer edge of the aperture is smaller than a predetermined diameter. Preferably, the storage means does not store the first aperture information when the diameter of the outer edge of the aperture is smaller than a predetermined diameter. Preferably, the storage means stores aperture information according to the type of the image sensor 122, and the communication means transmits the aperture information according to the type of the image sensor to the camera body. Preferably, the communication means transmits the aperture information for each signal acquisition frame of the imaging device.

Preferably, a unit (converter lens unit 600) is removably attachable between the lens device and the imaging device, and the aperture information includes third aperture information regarding the baseline length when the unit is attached to the lens device. More preferably, the lens device includes calculation means (lens MPU 117) that calculates the fourth aperture information based on the optical information of the unit and the second aperture information. The communication means transmits the third aperture information and the fourth aperture information to the imaging device.

Further, in each embodiment, the imaging device has a removable lens device, an imaging element, a communication means (camera MPU 125), and a calculation means 129b. The communication means receives, from the lens device, aperture information of an imaging optical system having a transmittance distribution layer that is rotationally symmetrical with respect to the optical axis. The calculation means calculates a defocus conversion coefficient based on the aperture information. The aperture information includes first aperture information regarding the baseline length of the imaging optical system having the transmittance distribution layer.

According to each embodiment, an accurate defocus amount can be calculated by holding and communicating aperture information calculated in consideration of the transmittance distribution of the imaging optical system having the transmittance distribution layer. Therefore, according to each embodiment, it is possible to provide a lens device, an imaging device, a communication method, and a program that can calculate a defocus conversion coefficient without increasing storage capacity and calculation time.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

100 Lens unit (lens device)
105 Transmittance distribution layer 117 Lens MPU (communication means)
118 Lens memory (storage means)

Claims (18)

A lens device that can be attached to and detached from an imaging device,
an imaging optical system having a transmittance distribution layer rotationally symmetrical about the optical axis;
storage means for storing aperture information that defines a light-receiving area of the image sensor by the imaging optical system;
a communication means for transmitting the aperture information to the imaging device,
The aperture information is used to calculate a defocus conversion coefficient when the imaging device performs focus detection, and includes first aperture information corresponding to a change in baseline length due to the transmittance distribution layer. lens device. The communication means transmits first aperture information corresponding to at least one of a zoom state, a focus state, or an aperture value of the imaging optical system, out of the first aperture information stored in the storage means, to the imaging device. 2. The lens device according to claim 1, wherein the lens device transmits the information to:. 3. The lens device according to claim 1, wherein the aperture information includes second aperture information regarding at least one of an aperture value, a light amount, and a depth. 4. The base line length is determined based on light receiving sensitivity characteristics of a first pixel and a second pixel of an image sensor and a transmittance distribution of the transmittance distribution layer. The lens device according to item 1. The imaging optical system has a diaphragm that adjusts the amount of light during imaging by adjusting the aperture diameter,
The first aperture information is determined based on at least one of an outer edge defining the aperture diameter of the diaphragm or an outer edge of the aperture of the imaging optical system, and a transmittance distribution of the transmittance distribution layer. The lens device according to any one of claims 1 to 4, characterized in that: 6. The aperture area based on the first aperture information is smaller than each of an area surrounded by an outer edge defining the aperture diameter of the diaphragm and an area surrounded by an outer edge of the aperture. lens device. The difference between the aperture area based on the aperture information and the area surrounded by the outer edge defining the aperture diameter of the aperture or the area surrounded by the outer edge of the aperture is determined by The lens device according to claim 5 or 6, wherein the smaller the lens device, the smaller the lens device. 8. The communication means does not transmit the first aperture information to the imaging device when a diameter of an outer edge defining the aperture diameter of the diaphragm is smaller than a predetermined diameter. The lens device according to item 1. 9. The storage means does not store the first aperture information when the diameter of the outer edge defining the aperture diameter of the diaphragm is smaller than a predetermined diameter. The lens device described. The storage means stores the aperture information according to the type of image sensor,
The lens device according to any one of claims 1 to 9, wherein the communication means transmits the aperture information according to the type of the image pickup device to the image pickup device. 11. The lens device according to claim 1, wherein the communication means transmits the aperture information for each signal acquisition frame of the imaging device. A unit is removable between the lens device and the imaging device,
4. The lens device according to claim 3, wherein the aperture information includes third aperture information regarding a baseline length when the unit is attached to the lens device. 13. The lens device according to claim 12, wherein the unit is a converter lens unit. further comprising calculation means for calculating fourth aperture information based on the optical information of the unit and the second aperture information,
14. The lens device according to claim 12, wherein the communication means transmits the third aperture information and the fourth aperture information to the imaging device. The first aperture information is information for changing the baseline length when the imaging optical system does not have the transmittance distribution layer to the baseline length when it has the transmittance distribution layer. A lens device according to any one of claims 1 to 14. An imaging device with a detachable lens device,
An image sensor and
communication means for receiving, from the lens device, aperture information that defines a light-receivable area of an imaging element by an imaging optical system having a transmittance distribution layer that is rotationally symmetrical with respect to the optical axis;
a calculation means for calculating a defocus conversion coefficient based on the aperture information,
The imaging device is characterized in that the aperture information includes first aperture information regarding a baseline length that corresponds to a change in baseline length due to the transmittance distribution layer. A communication method between an imaging device and a lens device including an imaging optical system having a transmittance distribution layer rotationally symmetrical with respect to an optical axis, the method comprising:
acquiring aperture information that defines a light-receiving area of an image sensor by the imaging optical system from a storage means of the lens device;
transmitting the aperture information to the imaging device,
The aperture information is used to calculate a defocus conversion coefficient when the imaging device performs focus detection, and includes first aperture information regarding a baseline length corresponding to a change in baseline length due to the transmittance distribution layer. A communication method characterized by: A program that causes a computer to execute the communication method according to claim 17 .