Imaging device, exposure control method, and program

Abstract

This invention provides an imaging device, an exposure control method, and a program that enable natural exposure tracking when the focus position is moved using manual focus (MF) operation. [Solution] A camera equipped with a focus ring that allows the user to change the current focus position, when a first subject and a second subject are detected from an captured image, acquires information corresponding to the positions of the first and second subjects by the distance measuring unit, calculates information regarding the brightness of the first and second subjects by the photometering unit, and controls the exposure when the focus position moves based on the information regarding the brightness and the position of the first and second subjects.

Description

[Technical Field]

[0001] The present invention relates to an imaging device, an exposure control method, and a program, and more particularly to an imaging device, an exposure control method, and a program that perform automatic exposure control when a user moves the focus position to different subjects within the field of view using manual focus (MF) operation. [Background technology]

[0002] Conventionally, in photography using digital cameras (hereinafter simply referred to as cameras), exposure control is performed automatically by the AE (Auto Exposure) function. One known method of AE is to control the exposure so that the subject detected by the camera (such as a person's face) is at the appropriate brightness. In cases where there are multiple subjects within the field of view, a method is known in which the main subject is determined by the size of the subjects, and the exposure is adjusted to that main subject (see, for example, Patent Document 1).

[0003] Furthermore, camera focus control is known to have two main methods: AF (Auto Focus), where the camera automatically adjusts the focus, and MF (Manual Focus), where the user can manually move the focus point.

[0004] Now, let's consider the case where there are two people with different depths of field within the frame. Figure 1 shows the relative positions of the camera and the people in this case. In this scene, as shown in Figure 1, people 102 and 103 are in the foreground and background relative to camera 101, respectively. Note that in the scene in Figure 1, due to the lighting, person 103 is in a darker position than person 102.

[0005] Figure 2 shows the image acquired by the camera at this time. The image 201 of person 102, which is in focus, is shown as a solid line, and the image 202 of person 103, which is out of focus, is shown as a dotted line.

[0006] For such scenes, for example, Patent Document 2 proposes a method in which images are captured while changing the focus position before shooting, and the focus area of ​​each image is detected and photometered, making it possible to adjust the exposure to each focus area when the focus position is moved. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-105850 [Patent Document 2] Japanese Patent Publication No. 2008-172516 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, Patent Document 2 does not take into account the speed at which the user moves the focus position at an arbitrary speed during manual focus operation when controlling the exposure.

[0009] The problems arising from this type of exposure control are explained using Figure 3, with Figure 2 illustrating the case where the focus position is moved from person 102 to person 103 using manual focus (MF).

[0010] Figure 3 shows the images acquired while the focus position is shifting. Starting from state 303, where the focus is on the image 301 of the person 102 in the foreground, as the focus position shifts to the image 302 of the person 103 in the background, initially neither person 102 nor person 103 is completely in focus, but the degree of focus is person 102 < person 103. Subsequently, the image transitions to state 304, where the focus is on the image 302 of the person 103 in the background.

[0011] Now, let's consider the case where the main subject is determined using the method disclosed in Patent Document 1. In this case, the main subject changes from state 303, where the person 102 in the foreground is the main subject, to state 304, where the focus is on person 103, which is the main subject.

[0012] Furthermore, the optimal AE for each of states 303 to 305 is as follows. First, in state 303, the person 102 in the foreground becomes the main subject, so the exposure is set to match the image 301 of person 102. Next, in state 304, the moment the main subject switches to the image 302 of person 103 in the background, the system operates to set the exposure to match the image 302 of person 103. Here, since the brightness of the image 302 of person 103 is lower than that of person 102, the exposure transitions towards becoming brighter. After that, until state 305, the image 302 of person 103 in the background becomes the main subject, so the operation of setting the exposure to match the image 302 of person 103 continues.

[0013] Let's consider exposure control when the focus position is moved as shown in Figure 3, specifically the case where the user moves the focus position slowly using manual focus (MF) operation. Here, MF operation is the operation in which the user arbitrarily moves the focus position, for example, by rotating the focus ring on the camera, and the focus position changes at a speed corresponding to the speed of rotation of the focus ring.

[0014] If the user performs a slow manual focus (MF) operation in relation to the exposure control operation shown in Figure 3 above, the focus position will change slowly, while the exposure control will change abruptly when the main subject changes (state 304). Since the user sets the speed of focus position change due to MF operation, it is difficult for the camera to predict. Therefore, the discrepancy between the speed of focus position change and the speed of exposure change results in unnatural exposure control in the image, which is a problem.

[0015] Therefore, the object of the present invention is to provide an imaging device, an exposure control method, and a program that enable natural exposure tracking when the focus position is moved using manual focus (MF) operation. [Means for solving the problem]

[0016] In order to solve the above problems, the imaging device according to claim 1 of the present invention is an imaging device including a changing unit that changes the current focus position by a user operation, and includes an imaging unit that captures an image, a detection unit that detects a subject from the image, a subject position acquisition unit that acquires information corresponding to the position of the subject detected by the detection unit, a calculation unit that calculates information regarding the luminance of the subject detected by the detection unit, and when the detection unit detects a first subject and a second subject as the subject, the subject position acquisition unit acquires information corresponding to the position of the first subject and information corresponding to the position of the second subject, the calculation unit calculates information regarding the luminance of the first subject and information regarding the luminance of the second subject, and control means for controlling exposure when the focus position moves from the information regarding the luminance of the first subject and the second subject and the information corresponding to the position.

Effect of the Invention

[0017] According to the present invention, when the focus position is moved by an MF operation, natural exposure tracking can be achieved.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing the positional relationship between a camera and a person in a scene where there are two persons with a depth difference within the angle of view. [Figure 2] It is a diagram showing an image acquired by MF in the scene of FIG. 1. [Figure 3] It is a diagram showing an image acquired by the camera when the focus position is moved from the person in the foreground to the person in the background in the scene of FIG. 1. [Figure 4] It is a block diagram showing the hardware configuration of a camera as an imaging device according to the first embodiment of the present invention. [Figure 5] It is a diagram showing a shooting scene assumed in the first embodiment. [Figure 6] It is a flowchart of exposure control processing according to the first embodiment. [Figure 7]This figure shows the positional relationship between the camera and the person within the field of view in the shooting scene shown in Figure 5, as well as the current focus position achieved through manual focus (MF) operation. [Figure 8] Figure 5 shows the image recorded while MF operation is being performed during the shooting scene. [Figure 9] This graph shows the change in the third metering value M3 during manual focus operation in the shooting scene shown in Figure 5. [Figure 10] This is a flowchart of the exposure control process according to the second embodiment. [Figure 11] This diagram illustrates a shooting scene with a deep depth of field, as envisioned in the third embodiment. [Figure 12] This figure shows the positional relationship, including the tracking start threshold and tracking end threshold, in the shooting scene shown in Figure 11. [Figure 13] This graph shows the relationship between the third photometric value M'3 and the focus position according to the third embodiment, using the tracking start threshold and tracking end threshold. [Figure 14] This is a flowchart of the exposure control process according to the third embodiment. [Figure 15] This is an example screen showing how a user can set the tracking start threshold and tracking end threshold in Figure 12. [Figure 16] This is a flowchart of the exposure control process according to the fourth embodiment. [Figure 17] This is an example screen showing the user selecting two subjects in step S602 of Figure 16. [Figure 18] This diagram illustrates a shooting scene in which multiple subjects, which are candidates for the second subject, have roughly the same priority, as envisioned in the fifth embodiment. [Figure 19] This is a flowchart of the exposure control process according to the fifth embodiment. [Figure 20] This is a flowchart of the exposure control process according to the sixth embodiment. [Modes for carrying out the invention]

[0019] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention to the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0020] Embodiments of the present invention will be described below with reference to the drawings.

[0021] (First embodiment) Figure 4 is a block diagram showing the hardware configuration of camera 1 as an imaging device according to the first embodiment of the present invention. Camera 1 consists of a camera body 400 and a lens unit 401 that is detachable from the camera body 400. The configuration of camera 1 with the lens unit 401 attached to the camera body 400 will be described below with reference to Figure 4.

[0022] The camera body 400 comprises a camera system control unit 402, a memory 403, an image sensor 404, a shutter 405, an A / D conversion unit 406, an image processing unit 407, a memory control unit 408, a D / A conversion unit 409, and a display unit 410. Furthermore, the camera body 400 comprises a timing generator (hereinafter referred to as TG) 411, a release button 412, an operation unit 413, a detection unit 414, a photometering unit 415, and a distance measuring unit 416.

[0023] Furthermore, the lens unit 401 includes a lens system control unit 417, a photographic lens group 418, an aperture 419, and a focus ring 420.

[0024] The camera system control unit 402 is a control means that comprehensively controls each part of the camera body 400. The memory 403 is a memory such as RAM or ROM connected to the camera system control unit 402. The image sensor 404 (imaging means) is a charge-storage type image sensor such as a CMOS, which converts the light beam (optical image of the subject) incident through the lens unit 401 into photoelectric data and outputs analog image data (captured image). The shutter 405 is controlled to operate by a signal from the camera system control unit 402. The shutter 405 is controlled to switch between a light-shielding state that blocks the image sensor 404 from the light beam incident through the lens unit 401, and a retracted state that guides the optical image of the subject incident through the lens unit 401 to the image sensor 404.

[0025] The A / D conversion unit 406 is a conversion means that converts analog image data output from the image sensor 404 into digital image data, and the converted digital image data is recorded in the memory 403. The image processing unit 407 performs resizing processing such as predetermined image interpolation and reduction, color conversion processing, and calculation processing of the number of inaccurate pixel data such as saturated pixels and blacked-out pixels on the data from the A / D conversion unit 406 or the data from the memory control unit 408. The D / A conversion unit 409 is a conversion means that converts the digital image data recorded in the memory 403 into analog image data for display. The display unit 410 is a display means composed of a TFT type LCD (thin film transistor driven liquid crystal display) or the like, and can display analog image data for display. The display unit 410 can also perform live view display by sequentially displaying the analog image data output from the D / A conversion unit 409. In addition, the display unit 410 can also display various information other than the acquired image data. Furthermore, the display control of the display unit 410 is performed, for example, by the camera system control unit 402 (display control means) controlling the memory 403, the memory control unit 408, and an image drawing unit (not shown). The image drawing unit (not shown) generates superimposed image data by superimposing various information such as icons onto image data acquired from, for example, the memory 403, the image sensor 404, and the image processing unit 407. By controlling the camera system control unit 402 to display the generated superimposed image data on the display unit 410, the display unit 410 can perform live view display with various information superimposed, or image display.

[0026] TG411 is a timing generation means that transmits timings related to the operation of the camera 1 to various parts of the camera 1, such as the timing of exposure of the image sensor 404, changes in frame rate, and the timing of switching between the light-shielding state and the retracted state of the shutter 405.

[0027] The release button 412 and the operation unit 413 are operating means for inputting various operation instructions to the camera system control unit 402. The release button 412 is an instruction means for instructing the start of the image preparation operation and the image capture operation. When the user changes the release button 412 to the SW1 state (in this case, a half-press operation), the start of the image preparation operation is instructed, and distance measurement calculation processing, photometering calculation processing, etc. are started. Also, when the user changes the release button 412 to the SW2 state (in this case, a full-press operation), the start of the image capture operation is instructed, and a series of processes from capturing the subject to acquiring the image are started. The operation unit 413 is a group of input devices consisting of operating members such as switches, buttons, and dials for the user to give various instructions and settings to the camera body 400. For example, the operation unit 413 includes a power switch, a menu button, a direction indicator button, etc. In this embodiment, the display unit 410 is a touch panel display in which a TFT-type LCD and a capacitive touch panel are integrated, and the user can input information in the same way as when operating the operation unit 413 by operating the UI displayed on the display unit 410.

[0028] The detection unit 414 (detection means) uses image data obtained from the image processing unit 407 to perform detection processing for a specific subject. The photometric unit 415 (calculation means) uses image data obtained from the image processing unit 407 to calculate a photometric value that results in proper exposure for the detected subject, as information regarding the subject's brightness. The distance measuring unit 416 uses image data obtained from the image processing unit 407 to perform distance measurement calculations.

[0029] The detection unit 414, photometric unit 415, and distance measuring unit 416 described above may be configured to be integrated with the camera system control unit 402. In this case, the camera system control unit 402 performs various calculations in the detection unit 414, distance measuring unit 416, and photometric unit 415.

[0030] The lens system control unit 417 is a control means that comprehensively controls the operation of the lens unit 401. When the lens unit 401 is attached to the camera body 400, the lens system control unit 417 and the camera system control unit 402 can communicate via an interface (not shown). For example, in response to instructions from the camera system control unit 402, information regarding the lens unit 401 attached to the camera body 400 is output to the camera system control unit 402.

[0031] The photographic lens group 418 is a lens group consisting of multiple lenses, including optical axis shift lenses, zoom lenses, and focus lenses. The aperture 419 is a light intensity adjustment member for adjusting the amount of light beam transmitted through the photographic lens group 418, and its drive is controlled by the lens system control unit 417. Note that the lens unit 401 may not have a lens system control unit 417. In this configuration, the operation of the photographic lens group 418 and the aperture 419 is controlled by instructions from the camera system control unit 402.

[0032] The focus ring 420 (adjustment part) is a ring provided on the outer circumference of the lens unit 401, and is a component that adjusts the position of the photographic lens group 418 in accordance with the user's rotation operation of the focus ring 420 (user operation) to change the focus position. The amount of rotation of the focus ring 420 due to this rotation operation is input to the lens system control unit 417, and the lens system control unit 417 controls the position adjustment of the photographic lens group 418 according to the amount of rotation. Hereinafter, this operation by the user to change the focus position, which is the rotation operation of the focus ring 420, will be referred to as MF (manual focus) operation.

[0033] Camera 1 may also be provided with a recording medium 421, such as a memory card or hard disk, capable of recording image data stored in memory 403. Here, the recording medium 421 is exemplified as a memory card or the like, which is a recording medium that can be inserted into and removed from the camera body 400, but is not limited to this. For example, the recording medium 421 may be an optical disc such as a DVD-RW disc or a magnetic disc such as a hard disk. Furthermore, the recording medium 421 may not be removable but may be pre-built into the camera body 400.

[0034] The above describes the basic configuration of the camera 1 according to this embodiment.

[0035] The exposure control process according to this embodiment will be described below using the flowcharts in Figures 5 and 6. This process is executed by the camera system control unit 402, which loads the program stored in the ROM in the memory 403 into the RAM, which is also located in the memory 403.

[0036] Figure 5 is a diagram illustrating a shooting scene assumed in this embodiment.

[0037] In the scene shown in Figure 5, two people, 502 and 503, are within the field of view of camera 1. From the perspective of position 501 where camera 1 is positioned, person 502 is closer and person 503 is further away. In other words, it assumes a situation where there is a difference in the focus position between person 502 and person 503. Although Figure 5 illustrates a case where the subject of the photograph is a person, other subjects such as animals or vehicles may also be used as the subject of the photograph.

[0038] The shooting method is assumed to be a case where the user moves the current focus position from the person 502 in the foreground to the person 503 in the background using manual focus (MF) operation while recording. However, the focus position may be moved in the opposite direction, i.e., from the person 503 in the background to the person 502 in the foreground, while recording. Furthermore, this embodiment and other embodiments described later are not limited to the case of recording, as long as the user can see the periodically captured frame images; for example, it may also be the case where live view is displayed in the shooting standby state.

[0039] Figure 6 is a flowchart of the exposure control process according to this embodiment. This process starts when the user half-presses the release button 412.

[0040] First, step S601 determines whether the focus setting is MF mode or AF mode. If it is MF mode (YES in step S601), proceed to step S602; if it is AF mode (NO in step S601), proceed to step S603.

[0041] If the process proceeds to step S603, the normal AF operation is performed. Here, the detection unit 414 detects the person 502 that is closest to the camera 1 within the field of view as the subject to be AF, moves the focus position to the position of person 502, and then calculates the metering value. After that, the process proceeds to step S609. On the other hand, if the process proceeds to step S602, the detection unit 414 detects both person 502 and person 503 within the field of view. After that, the process proceeds to step S604.

[0042] In step S604, the position information of person 502 and person 503 detected in step S602 is determined. In this embodiment, the distances of person 502 and person 503 to camera 1 at position 501 are determined as their respective position information from focus information (information corresponding to the position of the subject) obtained from distance measuring unit 416 (subject position acquisition means), but this is not limited to this. For example, the distances of person 502 and person 503 to camera 1 may be determined as their respective position information from ToF (Time Of Flight) information using an infrared light source and an infrared sensor.

[0043] Next, the process proceeds to step S605 to obtain the current focus position. The current focus position only needs to be information that shows the positional relationship between the focus position moved by the MF operation at that time and the people 502 and 503. For example, it can be calculated from the amount of rotation of the focus ring 420 provided on the lens unit 401.

[0044] Next, we proceed to step S606, where we calculate the ratio x that represents the positional relationship between the current focus position and persons 502 and 503, using the respective positional information of persons 502 and 503 obtained in step S604 and the current focus position obtained in step S605. For example, if person 502 is located 1.0m away from position 501 of camera 1, person 503 is located 1.5m away from position 501 of camera 1, and the current focus position is located Am away from position 501 of camera 1, then the ratio X% can be calculated using the following formula 1.

[0045]

number

[0046] Next, the process proceeds to step S607, where the photometer 415 performs photometry on the person 502 and person 503 detected in step S603, determining a first photometric value M1 that results in proper exposure for person 502 and a second photometric value M2 that results in proper exposure for person 503.

[0047] Next, we proceed to step S608, where the third photometric value M3 is determined from the current focus position ratio and the first and second photometric values ​​M1 and M2. The method for determining the third photometric value M3 is expressed by the following equation 2.

[0048]

number

[0049] According to equation (2) above, as the focus position moves from person 502 to person 503 by MF operation, the third photometric value M3 can be changed from the photometric value M1 of person 502 to the photometric value M2 of person 503. However, if the ratio X% becomes greater than 100%, the photometric value will move away from the second photometric value M2, and the third photometric value M3 will not match either the first photometric value M1 or the second photometric value M2. For this reason, if the ratio X calculated in equation (1) is greater than 100%, the ratio X is set to 100%. That is, the value of the third photometric value M3 is set to the second photometric value M2. Similarly, if the ratio X calculated in equation (1) becomes less than 0%, the third photometric value M3 will not match either the first photometric value M1 or the second photometric value M2, so the ratio X is set to 0%. In other words, the value of the third photometric value M3 is taken as the first photometric value M1.

[0050] Furthermore, Figures 7 and 8 will be used to explain the image quality obtained when recording video while moving the focus point using manual focus (MF) operation. Figure 7 shows the positional relationship between camera 1 (position 701), people 702 (focus point A) and 703 (focus point B) within the field of view in the shooting scene of Figure 5, and the current focus point due to MF operation. Here, we will explain a scene in which the focus point due to MF operation moves from focus point A at the start of movement, through focus point B, and to focus point C at the end of movement. In addition, in this shooting scene, person 703 is a darker subject compared to person 702.

[0051] Figure 8 shows images 801-803 recorded during manual focus operation in this shooting scene, and the relationship between the metering value M3 and the focus position is shown in the graph in Figure 9.

[0052] As indicated by the boxed text in each of the images 801 to 803 in FIG. 8, the images 804, 805, and 806 of the person on the left correspond to the person 702 in FIG. 7, and the images 807, 808, and 809 of the person on the right correspond to the person 703 in FIG. 7.

[0053] That is, the image 801 is an image (an image whose exposure is controlled based on the photometric value M which is the result of photometry of the image 804 of the person 702) corresponding to the focusing position A. A The image 803 is an image (an image whose exposure is controlled based on the photometric value M which is the result of photometry of the image 809 of the person 703) corresponding to the focusing position C. B The image 802 is an image (an image whose exposure is controlled based on the third photometric value M3 obtained by inputting the photometric value M as the first photometric value M1 and the photometric value M as the second photometric value M2 into Equation 2) corresponding to the focusing position B. A as the first photometric value M1 and the photometric value M B as the second photometric value M2 and is an image whose exposure is controlled based on the third photometric value M3 obtained thereby.

[0054] FIG. 9 is a graph showing the change in the third photometric value M3 during the MF operation in the shooting scene of FIG. 5.

[0055] In the image 801 that is first recorded and shot, the focusing position is at the position of the person 702 in the foreground (focusing position A). The photometric value M3 at this time is the photometric value M as shown in the graph of FIG. 9. A That is, since the exposure is controlled based on the photometry result of the person 702, the image 804 of the person 702 has an appropriate brightness.

[0056] Next, in the image 802 that is recorded and shot, the focusing position is in a state where the focusing position is at the intermediate position between the person 702 and the person 703 (focusing position B). The photometric value M3 at this time is, as shown in the graph of FIG. 9, M A +(M B -M A ) / 2. This equation is a calculation formula when X = 50 for the ratio X of the current focusing position according to Equation 2. Since the photometric value M3 at this time is the intermediate value between the person 702 and the person 703, the photometric value is M at the focusing position A AIt becomes smaller. Therefore, the exposure changes to a brighter setting, approaching the brightness at which the image 808 of the person 703 in image 802 is appropriate.

[0057] In the final recorded image 803, the focus point has been moved to the position of the person 703 in the background (focus position C). The photometric value M3 at this time is as shown in the graph in Figure 9. B This means that the exposure is controlled by the photometering result of the person 703 in the background, so the image 809 of person 703 has the appropriate brightness.

[0058] In this method, the final photometric value M3 is determined by the positional relationship between the positions of person 702 and person 703 in Figure 7 and the focus position moved by the manual focus (MF) operation. Therefore, if the user performs the MF operation slowly, the exposure will change slowly, and if the MF operation is performed quickly, the exposure will change quickly.

[0059] As described above, according to this embodiment, when the focus is moved from the first subject to the second subject using manual focus (MF) operation, the third metering value M3 is determined from the metering value M1 for the first subject and the metering value M2 for the second subject, based on the positions and focus positions of each subject. This allows for natural exposure tracking that matches the focus, even when the ring is operated slowly using MF operation.

[0060] (Second embodiment) The exposure control process according to the second embodiment of the present invention will be described below using the flowchart in Figure 10. In this embodiment, the same numbering will be used for components similar to those in the first embodiment, and redundant explanations will be omitted.

[0061] In this embodiment, the user can select AF (auto focus) mode, MF (manual focus) mode, and a hybrid mode (first mode) that allows the user to perform manual operations while in AF mode. Hereinafter, this hybrid mode will be referred to as full-time MF for convenience. Full-time MF mode normally performs AF operation, but when the user performs MF operation, such as when operating the focus ring 420, the AF operation is stopped and the focus position is changed according to the amount of movement of the focus ring 420.

[0062] The exposure control process in this embodiment is shown in the flowchart of Figure 10. The difference between the flowchart of Figure 10 and the flowchart of Figure 6 in the first embodiment is that step S1001 is included instead of step S601. Therefore, step S1001 will be described below. In Figure 10, the same numbering is used for steps that are the same as in Figure 6, and redundant explanations are omitted.

[0063] In step S1001, it is determined whether the selected focus mode is full-time MF and whether manual operation is currently in progress. If manual operation has not been performed for a certain threshold time and it is determined that manual operation is not in progress, the process from step S603 onwards is performed. Otherwise, it is determined that manual operation is in progress and the process from step S602 onwards is performed. This is because if the determination were made strictly based only on the most recent state, the result would change sensitively, so this is done to stabilize the result.

[0064] In other words, if manual operation is not in progress, the process proceeds to step S603, where normal AF operation is performed and the metering value is calculated according to the subject targeted by AF. If manual operation is in progress, the process proceeds to step S602, and the subsequent steps S602 and S604-S609 are performed.

[0065] As described above, according to this embodiment, when the focus setting of camera 1 is in full-time MF mode, the same effects as in the first embodiment can be obtained, and even when the ring is operated slowly in MF mode, natural exposure tracking that matches the focus can be achieved.

[0066] (Third embodiment) The exposure control process according to the third embodiment of the present invention will be described below with reference to Figures 11 to 14. In this embodiment, the same numbering will be used for components similar to those in the first embodiment, and redundant explanations will be omitted.

[0067] In this embodiment, we assume that the user has set the aperture 419 of the lens unit 401 to have a deep depth of field. Depth of field is the range in which the image is in focus along the optical axis, and it becomes shallower as the aperture 419 is opened and deeper as it is stopped down. In other words, when the focus point coincides with the subject, a shallow depth of field makes it appear as if only the subject is in focus, while a deep depth of field makes it appear as if a certain range in front of and behind the subject is also in focus.

[0068] Figure 11 shows the camera 1, the subjects (people 1104, 1105), the focus position, and the depth of field in a shooting scene assumed in this embodiment, where the depth of field is deep.

[0069] State 1101 shown in Figure 11 indicates that the position of the person 1104 in the foreground and the focus position coincide with the camera 1 positioned at position 1103, while state 1102 indicates that the focus position has been moved further back from camera 1 compared to state 1101.

[0070] In state 1101 shown in Figure 11, the focus is on person 1104 because the position of person 1104 and the focus point coincide. However, when the depth of field is this deep, person 1104 will be in focus even if it does not coincide with the focus point, as long as it is within the depth of field. In other words, even if the focus point is moved from person 1104's position to the back of camera 1, as in state 1102, if person 1104 is within the depth of field, the state in which person 1104 is in focus will continue.

[0071] In the first and second embodiments, in a scene where the focus position is moved from state 1101 to state 1102, when the focus position is moved by MF operation from state 1101, where the person 1104 is in focus, the third metering value M3 begins to change. Along with this, the exposure also begins to change. However, even when the focus position is moved by MF operation, as long as the person 1104 is within the depth of field and in focus, it is desirable to control the exposure with a metering value that matches the person 1104.

[0072] When the depth of field is shallow, as soon as the focus point starts to shift due to manual focus operation, the focus immediately goes out of focus on person 1104 and it starts to blur, so it is not a problem even if the exposure changes from the moment the focus point starts to shift. However, when the depth of field is deep, even when the focus point starts to shift due to manual focus operation, the focus remains on person 1104 until person 1104 moves out of the depth of field. Therefore, it becomes a problem that the exposure changes even when person 1104 is still in focus, as in state 1102. Note that this problem occurs not only when the focus point is near person 1104, but also when the focus point is near person 1105.

[0073] In this embodiment, to solve the above problems, a tracking start threshold and a tracking end threshold are provided between person 1104 and person 1105, as shown in Figure 12. The tracking start threshold represents the distance at which exposure tracking begins during the period in which the focus position moves from the position of person 1104 to the position of person 1105, and the reference distance is the position of person 1104. The tracking end threshold represents the distance at which exposure tracking ends during the period in which the focus position moves from the position of person 1104 to the position of person 1105, and the reference distance is the position of person 1105.

[0074] The tracking start threshold and tracking end threshold will be explained using Figures 12 and 13.

[0075] Figure 12 shows the positional relationships between camera 1, people 1104, 1105, the focus position, and the tracking start threshold and tracking end threshold when the focus position is moved from the position of person 1104 in the foreground to the position of person 1105 in the background with respect to camera 1 positioned at position 1103.

[0076] Here, we assume a state where M1 > M2, where the metering value for person 1104 is M1 and the metering value for person 1105 is M2. The focus position moves from the position of person 1104 to the position of person 1105 by the user's MF operation, but if the focus position is between the position of person 1104 and the tracking start threshold (section 1204), the metering value M1 of person 1104 is used as a third metering value M'3 for exposure control.

[0077] Furthermore, if the focus position is between the tracking start threshold and the tracking end threshold (interval 1205), first, the ratio X'% of the focus position to the positions of the tracking start threshold and the tracking end threshold is calculated as follows.

[0078] For example, if the tracking start threshold is 1.2m away from camera 1, the tracking end threshold is 1.4m away from camera 1, and the current focus position is Bm away from camera 1, the percentage X'% can be calculated using the following equation 3.

[0079]

number

[0080] Next, using the percentage X'%, the photometric value M1 of person 1104, and the photometric value M2 of person 1105, a third photometric value M'3 is obtained using the following equation 4 and used for exposure control.

[0081]

number

[0082] If the focus position is between the tracking termination threshold and the position of person 1105 (section 1206), the photometric value M2 of person 1105 is used as a third photometric value M'3 for exposure control.

[0083] In other words, if the focus position moves between person 1104 and the tracking start threshold (section 1204), and between the tracking end threshold and person 1105 (section 1206), the camera controls the exposure so as not to change the metering value used for exposure control. Note that depth of field A shown in Figure 12 represents the depth of field when the focus position is aligned with person 1104, and depth of field B represents the depth of field when the focus position is aligned with person 1105. It is desirable to set the tracking start threshold and tracking end threshold to the depth of field when the focus position is aligned with each subject, as shown in Figure 12.

[0084] The relationship between the distance to the focus position and the third photometric value M'3 in Figure 12 above is shown in the graph in Figure 13. First, while the focus position is between person 1104 and the tracking start threshold, the third photometric value M'3 used for exposure control remains constant at the value of the photometric value M1 of person 1104. Next, while the focus position is between the tracking start threshold and the tracking end threshold, the photometric value M'3 used for exposure control changes from the photometric value M1 of person 1104 to the photometric value M2 of person 1105. Finally, while the focus position is between the tracking end threshold and person 1105, the photometric value M'3 used for exposure control remains constant at the value of the photometric value M2 of person 1105.

[0085] Figure 14 is a flowchart of the exposure control process according to this embodiment. The difference between the flowchart in Figure 10 and the flowchart in Figure 6 in the first embodiment is that steps S1406 to S1411 are included instead of steps S606 to S608. Therefore, steps S1406 to S1411 will be described below. Note that in Figure 14, the same numbering is used for steps that are the same as in Figure 6, and redundant explanations are omitted.

[0086] First, steps S601 to S605 execute the same process as shown in the flowchart in Figure 6.

[0087] Step S605 is followed by step S1406, in which the tracking start threshold and tracking end threshold are set (setting means). Here, the tracking start threshold and tracking end threshold are calculated according to the respective positions of the people 1104 and 1105 and the depth of field. Furthermore, the respective values ​​of the tracking start threshold and tracking end threshold may be adjusted manually by the user, or the camera system control unit 402 may adjust them automatically.

[0088] Figure 15 illustrates an example screen showing the user manually adjusting the tracking start threshold and tracking end threshold values. Figure 15 shows the live view screen on the display unit 410 before shooting.

[0089] The number line 1503 at the bottom of the screen in Figure 15 has an adjustment bar 1504 (first icon) for adjusting the tracking start threshold and an adjustment bar 1505 (second icon) for adjusting the tracking end threshold. The positions of adjustment bars 1504 and 1505 represent the relative positions of the tracking start threshold and tracking end threshold with respect to camera 1. The left and right ends of the number line 1503 represent the relative positions 1501 of person 1104 and 1502 of person 1105 with respect to camera 1. The user can manually adjust the tracking start threshold and tracking end threshold by dragging the adjustment bars 1504 and 1505 on the number line 1503.

[0090] Next, we will explain an example of when the camera system control unit 402 automatically adjusts the values ​​of the tracking start threshold and the tracking end threshold. In the case of automatic adjustment, for example, the threshold may be adjusted according to the absolute value of the difference in metering values ​​between the foreground and background subjects (=|M1-M2|). If the absolute value of the difference in metering values ​​between the foreground and background subjects is large, the amount of exposure change when the focus position is moved will be large, and if the interval from the tracking start threshold to the tracking end threshold becomes short, the rate of exposure change tends to become steep. Here, if the exposure change is steep, it may be perceived as exposure flickering in video shooting. Therefore, in order to reduce this problem, an automatic adjustment method can be considered in which the interval from the tracking start threshold to the tracking end threshold becomes longer the greater the difference in metering values ​​of the subjects.

[0091] Returning to Figure 14, we then proceed to step S1407, where the photometric values ​​of the subjects detected in step S602 (in this case, people 1104 and 1105) are calculated. This is the same as step S607 in Figure 6, which is the first embodiment.

[0092] Next, the process proceeds to step S1408 to determine which section the focus position is in. The sections classified here are the three sections 1204-1206 in Figure 12, namely, the section from the subject in front of camera 1 to the tracking start threshold, the section from the tracking start threshold to the tracking end threshold, and the section from the tracking end threshold to the subject in the background relative to camera 1. If the focus position is in the section from the subject in front to the tracking start threshold, the process proceeds to step S1409, and the photometric value of the subject in front is used for exposure control in the subsequent step S609. If the focus position is between the tracking start threshold and the tracking end threshold, the process proceeds to step S1410, where, first, the percentage X'% of the focus position between the tracking start threshold and the tracking end threshold is calculated using equation 3. Next, using equation 4, the photometric value to be used for exposure control in the subsequent step S609 is calculated from the calculated percentage X'% and the photometric values ​​of the subjects in front and in the background. In other words, setting the tracking start threshold to 0% and the tracking end threshold to 100%, the percentage X'% at which the current focus position is located is calculated. If the focus position is between the tracking end threshold and the subject in the background, the process proceeds to step S1411, where the photometric value of the subject in the background is used for exposure control in the subsequent step S609. Finally, the process proceeds to step S1412, where exposure control is performed based on the obtained photometric values.

[0093] As described above, according to this embodiment, by providing a tracking start threshold and a tracking end threshold, exposure tracking can be performed in conjunction with the degree of focus of each subject that becomes the in-focus position at the start and end of MF operation.

[0094] (Fourth embodiment) The exposure control process of the fourth embodiment of the present invention will be described below using the flowchart in Figure 16 and Figure 17. In this embodiment, the same numbering will be used for components similar to those in the first embodiment, and redundant explanations will be omitted.

[0095] In this embodiment, we assume a case where there are three or more subjects within the field of view.

[0096] The exposure control process in this embodiment is shown in the flowchart of Figure 16. The difference between the flowchart of Figure 16 and the flowchart of Figure 6 in the first embodiment is that steps S1604 and S1605 are included instead of step S604. Therefore, steps S1604 and S1605 will be described below. Note that in Figure 16, the same numbering is used for steps that are the same as in Figure 6, and redundant explanations are omitted.

[0097] First, steps S601 to S603 execute the same process as shown in the flowchart in Figure 6.

[0098] After step S602, the process proceeds to step S1604, where two subjects are selected from the subjects detected in step S602 (selection means). One of the two subjects selected here is designated as the first subject, and the other as the second subject. The selection method may be arbitrarily chosen by the user, or it may be automatically selected by camera 1.

[0099] An example screen for when the user makes a selection will be explained using Figure 17. Figure 17 shows a live view screen of a scene in which three subjects have been detected within the field of view, as displayed on the display unit 410. When there are three subjects within the field of view, one possible method is to display the faces of the detected people 1701 to 1703 with user-selectable frames 1704 to 1706 attached to each, as shown in Figure 17, and allow the user to select two frames from the displayed frames 1704 to 1706. One possible method of user selection is to touch the display unit 410 to select the frames attached to the two target subjects. For example, the subject selected first by touch will be designated as the first subject, and the subject selected later by touch will be designated as the second subject.

[0100] Next, an example of how camera 1 automatically selects a subject will be explained using Figure 17. One way camera 1 automatically selects a subject is to choose the subject closest to the current focus position in the depth direction (person 1701 in the example of Figure 17) as the first subject, and then select a second subject from the remaining subjects. For example, one method is to calculate the priority of the remaining subjects using a priority calculation method that gives higher priority to larger subjects and subjects closer to the center of the screen, and then select the subject with the highest calculated priority as the second subject. In this case, person 1702 is selected as the second subject in Figure 17.

[0101] Returning to Figure 16, we proceed to step S1605, where we obtain location information for the subjects selected in step S1604. The processing is the same as in step S604 of Figure 6 in the first embodiment, except that the two target subjects were selected in step S1604.

[0102] Next, steps S605 and onward are performed in the same manner as in the first embodiment.

[0103] As described above, according to this embodiment, two target subjects are selected by the user's arbitrary selection or by the camera's automatic selection. This allows for natural exposure tracking that matches the movement of the focus point relative to the subject the user intends to focus on, even when there are three or more subjects within the field of view.

[0104] (Fifth embodiment) The exposure control process according to the fifth embodiment of the present invention will be described below using the flowcharts in Figures 18 and 19. In this embodiment, the same numbering will be used for components similar to those in the first embodiment, and redundant explanations will be omitted.

[0105] In this embodiment, the two target subjects are automatically selected by camera 1, similar to step S1604 of the fourth embodiment. However, in this embodiment, it is assumed that the priority of multiple subjects that could be candidates for the second subject is about the same, that is, that there are multiple subjects with the highest priority calculated in step S1604.

[0106] Figure 18 shows an example of the positional relationship between camera 1 and the three people 1802-1804 within the field of view when the priority of the two people 1803 and 1804, who are candidates for the second subject, is about the same.

[0107] As shown in Figure 18, consider a scene where three people 1802-1804 are within the field of view of camera 1, and people 1803 and 1804 are at the same depth (i.e., they are at approximately the same distance from camera 1). In such a scene, when camera 1 automatically selects a second subject in step S1604 of the fourth embodiment, we consider calculating the selection priority based on the proximity of the subject to camera 1 and the size of the subject in the acquired image. In this case, people 1803 and 1804 have the same priority, making it impossible to determine which one should be selected as the second subject.

[0108] In this embodiment, this is addressed by calculating the average of the photometric values ​​for person 1803 and person 1804, who have the same priority.

[0109] The exposure control process in this embodiment is as shown in the flowchart of Figure 19. The difference between the flowchart of Figure 19 and the flowchart of Figure 16 in the fourth embodiment is that step S1904 is added between steps S602 and S1604, and steps S1906 and S1907 are added between steps S1604 and S1605. In Figure 19, the same numbering is used for steps that are the same as in Figure 16, and redundant explanations are omitted.

[0110] First, steps S601 to S603 execute the same process as shown in the flowchart in Figure 16.

[0111] Following step S602, the process proceeds to step S1904, where the photometric value of the subject detected in step S602 is calculated. This step S1904 is the same process as step S607 in Figure 16 of the fourth embodiment, with only the order of the steps being changed.

[0112] Next, the process proceeds to step S1604, where two subjects are selected from the subjects detected in step S602. The selection method is assumed to be automatic selection by camera 1.

[0113] Next, the process proceeds to step S1906, where it is determined whether the two subjects are selectable in the selection process of step S1604, that is, whether there are subjects of the same priority when automatically selected based on criteria such as the size of the subjects. If they are selectable (no subjects of the same priority exist), the process proceeds to step S1908; if they are not selectable (subjects of the same priority exist), the process proceeds to step S1907.

[0114] If it is determined in step S1906 that a selection is not possible and the process proceeds to step S1907, the average of the photometric values ​​for subjects of the same priority is calculated (average value calculation means). The average of the photometric values ​​calculated here is used as the second photometric value M2 in the subsequent step S608. After that, the process proceeds to step S1908.

[0115] In step S1908, the position information of the two subjects selected in step S1604 is obtained. If it is determined in step S1906 that there are subjects of the same priority, the position information of one of the subjects of the same priority is obtained, since the distance from camera 1 of the subjects of the same priority is approximately the same. However, the average value of the position information of the subjects of the same priority may be obtained instead. After that, steps S605 and S606 are executed, and the process proceeds to step S608.

[0116] In step S608, the photometric value used for exposure control is calculated from the ratio of focus positions obtained in step S606 and the photometric value of the subject. Here, in step S608 in the first, second, and fourth embodiments, and in step S1410 which corresponds to step S608 in the third embodiment, the photometric value of a single subject is used as the second photometric value M2. In contrast, in step S608 of this embodiment, the average value of the photometric values ​​calculated in step S1906 may also be used as the second photometric value M2.

[0117] Finally, the process proceeds to step S609, where exposure control is performed based on the photometric value obtained in step S608, and the process ends.

[0118] As described above, according to this embodiment, when selecting two target subjects by automatic selection of the camera 1, similar to the fourth embodiment, if multiple subjects have the same priority and cannot be selected, the average of the metering values ​​of the subjects with the same priority is calculated. As a result, when there are three or more subjects in the field of view, natural exposure tracking is possible when moving the focus position, taking into account the metering values ​​of these subjects.

[0119] (Sixth embodiment) The exposure control process according to the sixth embodiment of the present invention will be described below using the flowchart in Figure 20. In this embodiment, the same numbering will be used for components similar to those in the first embodiment, and redundant explanations will be omitted.

[0120] In this embodiment, we assume a case where the exposure tracking speed is fast and the exposure fluctuations are steep when the focus position is moved by MF operation.

[0121] In the first embodiment, when the positional relationship is as shown in Figure 1, if the difference in photometric values ​​between person 102 and person 103 is large, the amount of exposure change when moving the focus position from person 102 to person 103 will be large. Also, if the distance between person 102 and person 103 is small, the time it takes to move the focus position from person 102 to person 103 will be shorter, resulting in a faster exposure change rate. When these conditions are combined, the exposure change when moving the focus position becomes steep.

[0122] When such abrupt exposure fluctuations occur, the entire screen of the display unit 410 appears to flicker during live view display. This problem arises when the issue of overall screen flickering takes precedence over the correlation between the movement of the focus position and the exposure fluctuations.

[0123] The exposure control process in this embodiment is shown in the flowchart of Figure 20. The difference between the flowchart in Figure 20 and the flowchart in Figure 6 of the first embodiment is that steps S2009 to S2011 are included between steps S608 and S609. In Figure 20, the same numbering is used for steps that are the same as in Figure 6, and redundant explanations are omitted.

[0124] First, in steps S601 to S608, the same process as in the flowchart in Figure 6 is executed.

[0125] Next, the process proceeds to step S2009 to calculate the exposure tracking speed (tracking speed calculation means). The exposure tracking speed is determined by, for example, storing the photometric value used for exposure control in the previous frame in memory 403 and calculating the difference between the photometric value of the previous frame and the photometric value of the current frame. In other words, the larger the difference in photometric values, the faster the exposure tracking speed calculated in step S2009.

[0126] Next, the process proceeds to step S2010, where it is determined whether the exposure tracking speed calculated in step S2009 exceeds the upper limit. The upper limit is set in advance and may be a value specified by the user from the menu settings, or a value pre-set for camera 1. If the exposure tracking speed does not exceed the upper limit (NO in step S2010), the process proceeds to step S609. If it exceeds the upper limit (YES in step S2010), the process proceeds to step S2011.

[0127] If it is determined in step S2010 that the exposure tracking speed exceeds the upper limit and the process proceeds to step S2011, the metered value is calculated based on the upper limit of the exposure tracking speed. For example, if the exposure tracking speed was calculated from the difference between the metered values ​​of the previous frame and the current frame, the metered value of the current frame is calculated so that the difference in metered values ​​is equal to the upper limit. After that, the process proceeds to step S609.

[0128] Finally, the process proceeds to step S609, where exposure control is performed based on the obtained photometric value, and then the process ends.

[0129] As described above, according to this embodiment, by setting an upper limit on the exposure tracking speed, it is possible to prevent abrupt exposure fluctuations while performing natural exposure tracking that matches the focus.

[0130] (Other embodiments) In the above embodiments, the imaging device according to the present invention was described as a personal digital camera, but it is not limited to this. That is, as long as it is equipped with an imaging function and an image synthesis function and has a user interface for setting the exposure time, the imaging device according to the present invention may be a portable device, a smartphone, or a network camera connected to a server. In addition, some of the processing described above may be performed by a portable device, a smartphone, or a network camera connected to a server.

[0131] The present invention can also be realized by supplying a program that implements one or more of the functions of this embodiment to a system or device via a network or recording medium, and by having one or more processors in the computer of that system or device read and operate the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0132] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention.

[0133] 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 are possible within the scope of its gist.

[0134] This embodiment includes the following configurations, methods, and programs. (Configuration 1) An imaging device comprising an imaging means for changing the current focus position by user operation, the imaging device comprising: an imaging means for capturing an image; a detection means for detecting a subject from the image; a subject position acquisition means for acquiring information corresponding to the position of the subject detected by the detection means; a calculation means for calculating information regarding the brightness of the subject detected by the detection means; and, when the detection means detects a first subject and a second subject as the subject, the subject position acquisition means acquires information corresponding to the position of the first subject and information corresponding to the position of the second subject, the calculation means calculates information regarding the brightness of the first subject and information regarding the brightness of the second subject, and a control means for controlling the exposure when the focus position moves based on the information regarding the brightness and position of the first subject and the second subject. (Configuration 2) The imaging device according to Configuration 1, characterized in that the subject position acquisition means acquires information corresponding to the position of the subject detected by the detection means from the distance between the subject detected by the detection means and the imaging device, which is obtained from either focus information or ToF (Time Of Flight) information. (Configuration 3) The imaging apparatus according to Configuration 1 or 2, characterized in that the control means is executed when the focus setting is in MF mode, in which the user manually adjusts the focus position. (Configuration 4) An imaging device according to any one of Configurations 1 to 3, wherein the focus setting is an AF mode that automatically adjusts the focus position, but further comprises a first mode that changes the current focus position when a user operation is performed on the modification unit, and the control means is executed when the focus setting is in the first mode and the user operation is in progress. (Configuration 5) The imaging device according to any one of Configurations 1 to 4, further comprising setting means for setting an exposure tracking start threshold and a tracking end threshold according to information corresponding to the position of the first subject, information corresponding to the position of the second subject, and depth of field, wherein the control means performs exposure control based on information relating to the brightness and position of the first subject and the second subject when the current focus position is between the tracking start threshold and the tracking end threshold. (Configuration 6) The imaging device according to Configuration 5, characterized in that the setting means sets the tracking start threshold according to the position of the first subject and the depth of field when the position of the first subject is closer to the imaging device than the position of the second subject, sets the tracking end threshold according to the position of the second subject and the depth of field, performs exposure control using information about the brightness of the first subject when the current focus position is less than the tracking start threshold, and performs exposure control using information about the brightness of the second subject when the current focus position is greater than the tracking end threshold. (Configuration 7) The imaging apparatus according to Configuration 6, characterized in that the control means adjusts the values ​​of the tracking start threshold and the tracking end threshold according to the difference between the information regarding the brightness of the first subject and the information regarding the brightness of the second subject. (Configuration 8) The imaging device according to Configuration 6 or 7, further comprising a display control means for displaying information on the display unit indicating the relative positions of the position of the first subject, the position of the second subject, the tracking start threshold, and the tracking end threshold with respect to the imaging device, wherein a first icon for adjusting the tracking start threshold by user operation is provided at the relative position of the tracking start threshold, and a second icon for adjusting the tracking end threshold by user operation is provided at the relative position of the tracking end threshold. (Configuration 9) The imaging device according to any one of Configurations 1 to 8, further comprising a selection means for selecting two subjects from the three or more subjects detected by the detection means, wherein one of the two subjects selected by the selection means is designated as the first subject and the other as the second subject. (Configuration 10) The imaging apparatus according to Configuration 9, further comprising a display control means that displays on a display unit an image in which a user-selectable frame is attached to each of the three or more subjects detected by the detection means, wherein the selection means selects from the displayed frames the subjects to which each of the two user-selected frames is attached as the two subjects. (Configuration 11) The imaging apparatus according to Configuration 9, wherein the selection means selects the subject closest to the current focus position in the depth direction from among the three or more subjects as the first subject, and selects the second subject from the remaining subjects. (Configuration 12) The imaging apparatus according to Configuration 11, characterized in that the selection means calculates a priority for each of the remaining subjects using a predetermined priority calculation method, and selects the subject with the highest calculated priority among the remaining subjects as the second subject. (Configuration 13) The imaging apparatus according to Configuration 12, further comprising an average value calculation means for calculating the average value of the photometric values ​​of each of the multiple subjects if there are multiple subjects among the remaining subjects that have the highest calculated priority. (Configuration 14) An imaging device according to any one of Configurations 1 to 13, further comprising a tracking speed calculation means for calculating the exposure tracking speed, wherein the control means controls the exposure when the focus position moves based on the upper limit value when the exposure tracking speed exceeds a preset upper limit value. (Method 1) An exposure control method for an imaging device equipped with a change unit that changes the current focus position by user operation, comprising: an imaging step of capturing an image; a detection step of detecting a subject from the image; a subject position acquisition step of acquiring information corresponding to the position of the subject detected in the detection step; a calculation step of calculating information regarding the brightness of the subject detected in the detection step; and, if a first subject and a second subject are detected as the subject in the detection step, in the subject position acquisition step, information corresponding to the position of the first subject and information corresponding to the position of the second subject are acquired, in the calculation step, information regarding the brightness of the first subject and information regarding the brightness of the second subject are calculated, and a control step of controlling the exposure when the focus position moves based on the information regarding the brightness and position of the first subject and the second subject. (Program 1) A program for causing a computer to function as one of the means of an imaging device described in any one of configurations 1 to 14. [Explanation of Symbols]

[0135] 1 Camera 400 Camera Body 401 Lens Unit 402 Camera System Control Unit 403 memory 404 Image Sensor 405 Shutter 406 A / D Conversion Unit 407 Image Processing Unit 408 Memory Control Unit 409 D / A Conversion Section 410 Display section 411 TG 412 Release button 413 Operation section 414 Detection Unit 415 Photometry section 416 Ranging section 417 Lens System Control Unit 418 Photographing lens group 419 aperture 420 Focus Ring 421 Recording media

Claims

1. An imaging device equipped with a change unit that allows the user to change the current focus position, An imaging means for capturing an image, A detection means for detecting a subject from the aforementioned image, A subject position acquisition means that acquires information corresponding to the position of the subject detected by the detection means, A calculation means for calculating information regarding the brightness of the subject detected by the detection means, When the detection means detects a first subject and a second subject as the subject, The subject position acquisition means acquires information corresponding to the position of the first subject and information corresponding to the position of the second subject. The calculation means calculates information regarding the brightness of the first subject and information regarding the brightness of the second subject. A control means for controlling the exposure when the focus position moves based on information relating to the brightness and position of the first subject and the second subject, An imaging device characterized by comprising:

2. The imaging device according to claim 1, characterized in that the subject position acquisition means acquires information corresponding to the position of the subject detected by the detection means from the distance between the subject detected by the detection means and the imaging device, which is determined from either focus information or ToF (Time Of Flight) information.

3. The imaging apparatus according to claim 1, characterized in that the control means is performed when the focus setting is in MF mode, in which the user manually adjusts the focus position.

4. The focus setting is an AF mode that automatically adjusts the focus position, but it also includes a first mode that changes the current focus position if the user performs an operation on the aforementioned modification unit. The imaging apparatus according to claim 1, characterized in that the control means is executed when the focus setting is in the first mode and the user operation is in progress.

5. The system further includes setting means for setting an exposure tracking start threshold and an exposure tracking end threshold according to information corresponding to the position of the first subject, information corresponding to the position of the second subject, and depth of field. The control means is The imaging device according to claim 1, characterized in that when the current focus position is between the tracking start threshold and the tracking end threshold, exposure control is performed based on information relating to the brightness and position of the first subject and the second subject.

6. The setting means sets the tracking start threshold according to the position of the first subject and the depth of field when the position of the first subject is closer to the imaging device than the position of the second subject, and sets the tracking end threshold according to the position of the second subject and the depth of field. If the current focus position is smaller than the tracking start threshold, exposure control is performed using information about the brightness of the first subject. The imaging device according to claim 5, characterized in that, if the current focus position is greater than the tracking termination threshold, exposure control is performed using information regarding the brightness of the second subject.

7. The control means is The imaging apparatus according to claim 6, characterized in that the values ​​of the tracking start threshold and the tracking end threshold are adjusted according to the difference between the information regarding the brightness of the first subject and the information regarding the brightness of the second subject.

8. The system further includes a display control means that displays information indicating the relative positions of the first subject's position, the second subject's position, the tracking start threshold, and the tracking end threshold with respect to the imaging device on a display unit. A first icon is provided at the relative position of the tracking start threshold for user operation to adjust the tracking start threshold. The imaging apparatus according to claim 6, wherein a second icon for adjusting the tracking termination threshold by user operation is provided at the relative position of the tracking termination threshold.

9. If the detection means detects three or more subjects as subjects, the system further comprises a selection means for selecting two subjects from the three or more detected subjects. The imaging apparatus according to claim 1, characterized in that one of the two subjects selected by the selection means is designated as the first subject and the other as the second subject.

10. The system further includes a display control means that displays images on a display unit, each of the three or more subjects detected by the detection means, with a user-selectable frame attached to each of them. The imaging apparatus according to claim 9, characterized in that the selection means selects the subjects to which each of the two user-selected frames is attached from among the displayed frames as the two subjects.

11. The imaging apparatus according to claim 9, wherein the selection means selects the subject closest to the current focus position in the depth direction from among the three or more subjects as the first subject, and selects the second subject from the remaining subjects.

12. The aforementioned selection means is, For each of the remaining subjects, a priority is calculated using a pre-set priority calculation method. The imaging apparatus according to claim 11, characterized in that, from among the remaining subjects, the subject with the highest calculated priority is selected as the second subject.

13. The imaging apparatus according to claim 12, further comprising an average value calculation means for calculating the average value of the photometric values ​​of each of the multiple subjects if there are multiple subjects among the remaining subjects that have the highest calculated priority.

14. The system further includes a tracking speed calculation means for calculating the exposure tracking speed, The imaging apparatus according to claim 1, characterized in that the control means controls the exposure when the focus position moves based on a preset upper limit when the exposure tracking speed exceeds a preset upper limit.

15. An exposure control method for an imaging device, comprising a modification unit that changes the current focus position by user operation, The imaging step involves capturing an image, A detection step of detecting a subject from the aforementioned image, A subject position acquisition step, which acquires information corresponding to the position of the subject detected in the detection step, A calculation step which calculates information regarding the brightness of the subject detected in the detection step, If, in the detection step, a first subject and a second subject are detected as the subject, In the subject position acquisition step, information corresponding to the position of the first subject and information corresponding to the position of the second subject are acquired. In the calculation step, information regarding the brightness of the first subject and information regarding the brightness of the second subject are calculated, A control step that controls the exposure when the focus position moves based on information corresponding to the brightness and position of the first subject and the second subject, An exposure control method characterized by having the following features.

16. A program for causing a computer to function as each of the means of the imaging apparatus described in claim 1.

Images