Imaging device, its control method, and program

Abstract

This system suppresses exposure fluctuations caused by external disturbances, while enabling the capture of properly exposed images when exposure changes are necessary. [Solution] The system control unit 50 of the imaging device 100 detects the brightness of the subject, acquires the imaging settings during imaging, sets an exposure tolerance range that allows deviation from the exposure target value, and automatically controls the exposure during imaging. When imaging for video recording, if the imaging settings change, the system control unit 50 changes the exposure tolerance range from a first range to a second range that is narrower than the first range, and changes the exposure if the brightness of the subject is outside the exposure tolerance range.

Description

Technical Field

[0001] The present invention relates to an imaging device, its control method, and a program, and particularly to exposure control during imaging.

Background Art

[0002] Many video cameras have a so-called automatic exposure control function that automatically changes the brightness according to the subject being imaged (see, for example, Patent Document 1). In automatic exposure control, the brightness is determined from the luminance information of the subject, and various exposure parameters such as the aperture, ND filter, shutter, and sensitivity are changed so that the brightness becomes the appropriate exposure. Since these exposure parameters have different controllable resolutions, to what level the brightness of the subject can be approximated to the appropriate exposure depends on the resolution of each exposure parameter. For example, the coarsest resolution is stored in advance, and when the appropriate exposure falls within the width of the stored resolution, it is determined as the appropriate exposure, and subsequent control is stopped. As an example, if the coarsest resolution is 1 / 8 stop, the range within ±1 / 16 stop from the appropriate exposure is regarded as the appropriate exposure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the brightness during imaging is adjusted to follow the subject, the overall brightness of the screen changes due to the change in the brightness of the subject and the exposure change, resulting in a sense of discomfort. In movie and news imaging, this sense of discomfort is disliked, so the exposure setting is often set to manual (hand-operated) for imaging.

[0005] However, if the exposure value is maintained at a manually set value, and the brightness of the subject changes gradually or suddenly, overexposure or underexposure may occur. For example, when shooting with a fixed camera or in long take mode, changes in the environment or the appearance of an unexpected subject may cause overexposure or underexposure compared to the expected brightness.

[0006] The present invention aims to provide an imaging device that can capture images with proper exposure at the time of exposure change while suppressing exposure fluctuations caused by external disturbances. [Means for solving the problem]

[0007] The imaging device according to the present invention comprises a photometering means for detecting the brightness of a subject, an acquisition means for acquiring imaging settings at the time of imaging, a setting means for setting an exposure tolerance range that allows deviation from an exposure target value, and an exposure control means for automatically controlling the exposure at the time of imaging, wherein the setting means changes the exposure tolerance range from a first range to a second range narrower than the first range when the imaging settings acquired by the acquisition means change during video recording, and the exposure control means changes the exposure when the brightness of the subject falls outside the exposure tolerance range during video recording. [Effects of the Invention]

[0008] According to the present invention, it becomes possible to capture stable images with proper exposure at the time of exposure change while suppressing exposure fluctuations due to external disturbances. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing a schematic configuration of an imaging device according to an embodiment of the present invention. [Figure 2] This is a flowchart of the exposure control according to the first embodiment. [Figure 3] This is a schematic diagram showing the movement of the imaging environment, subject, and imaging device. [Figure 4]This figure shows the relationship between elapsed time, photometric value, and target value in exposure control according to the first embodiment, corresponding to Figure 3. [Figure 5] This is a flowchart of exposure control according to the second embodiment. [Figure 6] This figure shows the relationship between elapsed time, photometric value, and target value in exposure control according to the second embodiment, corresponding to Figure 3. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1 is a block diagram showing a schematic configuration of an imaging device 100 according to an embodiment of the present invention. In this case, the imaging device 100 is assumed to be a digital video camera mainly used for shooting video.

[0011] The imaging device 100 includes an aperture 101, a barrier 102, an imaging lens 103, an ND filter 104, a D / A converter 13, a memory control unit 15, an imaging unit 22, an A / D converter 23, an image processing unit 24, a display unit 28, a memory 32, a gyroscope 40, and a system control unit 50. The imaging device 100 also includes an I / F_18, a power supply unit 30, a system memory 52, a system timer 53, a non-volatile memory 56, a recording switch 61, a mode switching switch 60, an operation unit 70, and a power control unit 80.

[0012] The imaging lens 103 includes a zoom lens, a focus lens, a shift lens, etc., and forms an image of the subject on the imaging unit 22 (image sensor). The aperture 101 adjusts the amount of light incident on the imaging unit 22. The barrier 102 covers the imaging system, including the imaging lens 103, aperture 101, and imaging unit 22, to prevent dirt and damage to the imaging system. The ND filter 104 is a light-reducing filter that reduces the amount of light incident on the imaging unit 22 without affecting the color.

[0013] The imaging unit 22 has an image sensor such as a CCD or CMOS element that converts an optical image into an electrical signal. The imaging unit 22 also has functions such as controlling storage by an electronic shutter, changing the analog gain, and changing the readout speed. The A / D converter 23 converts the analog signal output from the imaging unit 22 into a digital signal (image data) and outputs it. The imaging unit 22 may also have the functions of the A / D converter 23.

[0014] The image processing unit 24 performs various processes on the data from the A / D converter 23 and the memory control unit 15, including pixel interpolation, resizing such as reduction, detection of brightness information, color information, characteristic subjects, color conversion, gamma correction, and digital gain addition. The image processing unit 24 also performs predetermined calculations using the image data from the A / D converter 23 and transmits the calculation results to the system control unit 50.

[0015] Image data output from the A / D converter 23 is written to the memory 32 via the image processing unit 24 and the memory control unit 15, or via the memory control unit 15. The memory 32 stores image data output from the A / D converter 23 and image data used for display on the display unit 28. The memory 32 has sufficient storage capacity to store moving images and audio for a predetermined period of time. The memory 32 also serves as memory for image display (video memory).

[0016] The D / A converter 13 converts the image display data stored in the memory 32 into an analog signal and supplies it to the display unit 28. The display unit 28 is equipped with a display device such as an LCD and displays an image according to the analog signal sent from the D / A converter 13. By converting the digital signal output from the A / D converter 23 and stored in the memory 32 into an analog signal using the D / A converter 13 and sequentially transferring it to the display unit 28 for display, an electronic viewfinder function is realized, enabling through-image display.

[0017] The system control unit 50 is a microcomputer that has at least one processor (CPU) and controls the entire imaging device 100. Based on the calculation results sent from the image processing unit 24, the system control unit 50 performs exposure control, distance measurement control, white balance control, etc. Specifically, the system control unit 50 performs TTL (through-the-lens) type AF (auto focus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, etc. Also, according to the movement or posture change of the imaging device 100 such as camera shake detected by the gyro 40, the system control unit 50 performs image blur correction by operating the shift lens of the imaging lens 103 or shifting the image by the image processing unit 24. The system control unit 50 performs display control by controlling the memory 32, D / A converter 13, display unit 28, etc.

[0018] The non-volatile memory 56 is a memory that can be electrically erased and stored, and for example, EEPROM is used. In the non-volatile memory 56, constants for the operation of the system control unit 50, programs, etc. are stored. The program includes a program for executing the processing according to each flowchart in FIGS. 2 and 5. A RAM is used for the system memory 52. In the system memory 52, constants for the operation of the system control unit 50, variables, programs read from the non-volatile memory 56, etc. are expanded. The system timer 53 measures the time used for various controls and the time of the built-in clock.

[0019] The mode switch 60, the recording switch 61, and the operation unit 70 are each operating means for inputting various operation instructions to the system control unit 50. The mode switch 60 switches the operating mode of the system control unit 50. The operating modes include, but are not limited to, video recording mode, still image recording mode, and playback mode. The video recording mode and still image recording mode further include multiple imaging modes such as auto imaging mode, auto scene detection mode, manual mode, various scene modes which are set according to the imaging scene, program AE mode, and custom mode. By operating the mode switch 60, it is possible to directly switch to any of the multiple imaging modes included in the video recording mode. Alternatively, after switching to the video recording mode with the mode switch 60, it may be possible to switch to any of the multiple modes included in the video recording mode using other operating members.

[0020] The recording switch 61 switches between the image capture standby state and the image capture state. When the recording switch 61 is turned on, the system control unit 50 starts a series of operations from reading the signal from the image capture unit 22 to writing image data (still image data, video data) to the storage medium 200. Each operating element of the operation unit 70 is assigned a function for each situation by touching the various function icons displayed on the display unit 28, and operates as various function buttons. Examples of function buttons include an end button, a back button, an image advance button, a jump button, a filter button, and an attribute change button. For example, when the menu button is pressed, various configurable menu screens are displayed on the display unit 28. The user can intuitively make various settings using the menu screen displayed on the display unit 28 and the four-way directional pad (up, down, left, and right) and the SET button.

[0021] The power control unit 80 is composed of a battery detection circuit, a DC-DC converter, a switch circuit for switching the energized block, etc., and detects the presence or absence of a battery, the type of battery, and the remaining battery level. Also, the power control unit 80 controls the DC-DC converter based on the detection results such as the remaining battery level and the instructions of the system control unit 50, and supplies the necessary voltage to each block including the storage medium 200 for the necessary period. The power supply unit 30 is a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, a Li-ion battery, an AC adapter, etc.

[0022] I / F_18 is an interface that enables communication between the system control unit 50 and a storage medium 200 such as a memory card or a hard disk and an external display device 300, etc. The storage medium 200 is a memory card for storing image data obtained by imaging, a semiconductor memory, a magnetic disk, etc., and may be built into the main body of the imaging device 100 or may be detachable. The external display device 300 receives the image signal output from the A / D converter 23 and processed by the image processing unit 24 from the I / F_18, and displays it after applying monitor gamma.

[0023] <First Embodiment> The exposure control method according to the first embodiment in the imaging device 100 will be described in detail. FIG. 2 is a flowchart of the exposure control according to the first embodiment. Each process (step) indicated by the S number in the flowchart of FIG. 2 is realized by the system control unit 50 developing the program stored in the non-volatile memory 56 in the system memory 52 and controlling the operations of each part of the imaging device 100.

[0024] Figure 3 is a schematic diagram showing the movement of the imaging environment, subject, and imaging device. Here, the imaging environment is broadly divided into two parts: the outdoors on the left side of Figure 3 and the indoors on the right side of Figure 3. The imaging device 100 tracks and images the main subject as it moves across these imaging environments (main subject follow). The ambient light outdoors is sunlight, and the ambient light indoors is illumination light. Here, it is assumed that during imaging, the signal with intermediate gamma applied is stored and the signal is output to the external display device 300. Figure 4 is a diagram showing the relationship between elapsed time, photometric value, and target value in exposure control according to the first embodiment when the imaging environment changes as shown in Figure 3.

[0025] The flowchart in Figure 2 will be explained with reference to Figures 3 and 4.

[0026] In S201, the system control unit 50 acquires photometric values ​​for the subject in order to obtain the brightness of the subject. For example, it acquires the average brightness value of the image data processed by the image processing unit 24 via the imaging system and A / D converter 23.

[0027] In S202, the system control unit 50 acquires the current camera information of the imaging device 100. The camera information includes information on parameters that affect the image quality, such as the brightness and color of the captured image (hereinafter referred to as "imaging settings"). For example, the system control unit 50 acquires the WB gain applied by the image processing unit 24 for white balance adjustment. The WB gain is a value that changes when the white balance setting is changed by an auto white balance function that calculates the white balance by obtaining an evaluation value from the subject, or by user operation, and is one of the imaging settings. The acquired WB gain may be, for example, the R gain value and the B gain value, or their ratio, etc. Alternatively, it may be the filter density of the ND filter 104, the detection result of the imaging scene performed by the system control unit 50 using the imaging results, or the likelihood of the assumed imaging scene, etc. Here, it is assumed that an imaging setting of R gain value / B gain value = 2 has been acquired.

[0028] In S203, the system control unit 50 saves the camera information acquired in S202 as the current camera information. At the same time, it saves the previously saved camera information as the previous camera information. Here, the previous camera information includes the imaging settings R gain value / B gain value = 1.9.

[0029] In S204, the system control unit 50 determines whether the imaging settings have changed. That is, it compares the current imaging settings saved in S203 with the previous imaging settings to determine whether the imaging settings have changed. If the system control unit 50 determines that the imaging settings have changed (YES in S204), it proceeds to S205; if it determines that the imaging settings have not changed (NO in S204), it proceeds to S206.

[0030] In the example above, the R gain / B gain value, one of the current imaging settings acquired in S202, is '2', while the previous R gain / B gain value saved in S203 was '1.9'. Since the values ​​are different, it is determined that the imaging settings have changed. Here, the targets of automatic exposure control are the aperture 101, shutter, gain (gain value independent of color), and ND, and changes in WB gain are not targets of automatic exposure control. In this case, there are two possible causes for the change in WB gain, and either cause is acceptable. One is that the photographer changed the WB gain manually because the imaging scene changed (in the example in Figure 3, the main subject moves from outdoors to indoors). The other is that the AWB function activated in response to the change in the imaging scene and the color evaluation value changed, which is when the WB gain was changed by the system control unit 50. Examples of exposure changes that are not targets of automatic exposure control include various manual operations, such as manually inserting or removing the ND filter 104 from the incident light path.

[0031] In this example, we determined whether the imaging settings matched or not, but it is also possible to determine whether the change in the imaging settings falls within a predetermined threshold. Alternatively, the distance between feature vectors, with several other imaging settings as one of the parameters, may be compared with a predetermined threshold.

[0032] In S205, the system control unit 50 reduces the exposure tolerance range, and then proceeds to S207. In S206, the system control unit 50 expands the exposure tolerance range, and then proceeds to S207.

[0033] Looking at the processing in S205 and S206 in Figure 4, firstly, in the region before time T1, no change in imaging settings is detected, resulting in a wide exposure tolerance range. Specifically, it allows for an exposure of up to ±2 stops from the target value.

[0034] If processing progresses from S204 to S205 at time T1 (i.e., if imaging settings other than the parameters targeted by automatic exposure control change), the exposure tolerance range is reduced (narrowed). Here, at time T1, the exposure tolerance range is reduced from the previous ±2 stops to ±1 / 2 stops. Scenes in which imaging settings other than the parameters targeted by automatic exposure control change are scenes in which the photographer intends to capture an image with appropriate exposure, such as when the photographer changes the WB gain, so the system will actively control the exposure to achieve proper exposure. Therefore, automatic exposure control is enabled at time T1.

[0035] The expansion of the exposure tolerance range at time T2 indicates that, while the exposure tolerance range was ±1 / 2 stop (after it was reduced to ±1 / 2 stop at time T1), the judgment in S204 was made, and as a result of proceeding to S206, the exposure tolerance range was expanded.

[0036] When changing the exposure tolerance range, the maximum range is set to the range within which the difference from the predetermined exposure target value is acceptable, and the minimum range is set to be wider than the control tolerance range, which depends on the control resolution and control error of each exposure parameter. After time T2, automatic exposure control is disabled to avoid frequent changes in the overall brightness of the screen due to changes in the brightness of the subject and changes in exposure.

[0037] Furthermore, the exposure tolerance range will not exceed the minimum range when reduced, and if the process proceeds to S205 when the exposure tolerance range has already reached the minimum range, it will be maintained at the minimum range. Similarly, the exposure tolerance range will not exceed the maximum range when increased, and if the process proceeds to S206 when the exposure tolerance range has already reached the maximum range, it will be maintained at the maximum range. The maximum and minimum ranges may each be set by user operation via the operation unit 70 within the range that can be set by the imaging device 100. The method for changing the exposure tolerance range may be to switch between a wide range and a narrow range with a single change, or the amount of change in a single change may be set to be small and controlled to change gradually.

[0038] In S207, the system control unit 50 compares the exposure target value with the photometric value obtained in S201. For example, the difference ΔY between the average luminance value Yn (photometric value) and the luminance target value Yt is expressed by the following equation (1). As can be seen from this equation, ΔY increases by 1 when the brightness doubles. In Figure 4, the luminance target value Yt (target value) is shown by a dashed line, and ΔY is shown by a solid line. [Mathematics 1] ΔY = log2(Yn / Yt) ... Equation (1)

[0039] In S208, the system control unit 50 determines whether the brightness of the subject (photometric value acquired in S201) is within an acceptable range. For example, it determines whether ΔY is within an acceptable range for the brightness reduced in S205. In this case, if the acceptable range is ±1 / 2 stop, then if ΔY is -1 / 2 stop or greater and less than +1 / 2 stop, it is determined to be within an acceptable range. The determination in S208 is to determine whether ΔY (solid line) is included in the exposure target value range at any given time in Figure 4. If the system control unit 50 determines that the photometric value is not within an acceptable range (NO in S208), it proceeds to S209; if it determines that the photometric value is within an acceptable range (YES in S208), it proceeds to S210.

[0040] In S209, the system control unit 50 enables automatic exposure control with respect to the exposure control mode, and then proceeds to S211. On the other hand, in S210, the system control unit 50 disables automatic exposure control with respect to the exposure control mode, and then proceeds to S211. Here, the exposure control mode refers to whether automatic exposure control is enabled or disabled. The determination results of whether automatic exposure control is enabled or disabled for each time period, which are determined from the detection of changes in imaging settings (S204) and the determination of whether the photometric value is within the acceptable range (S208), correspond to the automatic exposure control disabled time period (~T1, T2~) and the automatic exposure control enabled time period (T1~T2) in Figure 4.

[0041] In S211, the system control unit 50 determines whether automatic exposure control is enabled or disabled. If the system control unit 50 determines that automatic exposure control is enabled (YES in S211), it proceeds to S212. If it determines that automatic exposure control is disabled (NO in S211), it terminates the process. For example, if the process in S209 changes the automatic exposure control from disabled to enabled at time T1, the process proceeds to S212. On the other hand, if automatic exposure control was disabled, the process terminates without changing the exposure.

[0042] In S212, the system control unit 50 determines the exposure parameters subject to automatic exposure control. The pattern of variation of the exposure parameters is predetermined according to the program AE mode. For example, after changing from a small aperture state to F4.0, the shutter speed is changed from 1 / 250 to 1 / 60, and then after opening the aperture from F4.0, the sensitivity is increased from the lowest sensitivity to the highest sensitivity. How far the aperture can be opened or closed, and how far the lowest and highest sensitivity can be set, varies depending on the state of the imaging device 100 (zoom position, focus position, presence or absence of a filter, etc.) and exposure-related settings (sensitivity expansion function, gamma setting, etc.).

[0043] Based on the state of the imaging device 100 and exposure-related settings, information such as aperture and sensitivity is applied to the above-mentioned pattern of exposure parameter variation. For example, subject brightness BV can be calculated using the aperture value AV, shutter speed TV, and ISO sensitivity SV by the following formula (2). Note that the values ​​of BV, AV, TV, and SV are converted to APEX units. [Math 2] BV = AV + TV - SV ... Equation (2)

[0044] In S213, the system control unit 50 changes the exposure and terminates the process. Specifically, the system control unit 50 converts the exposure parameters obtained in S212 into control values ​​that can be set for the aperture 101, ND filter 104, imaging unit 22, A / D converter 23, and image processing unit 24, and transmits these control values ​​to each. In this way, the aperture, ND filter, shutter speed, and ISO sensitivity are changed to achieve the desired exposure.

[0045] Applying the above control to Figure 4, automatic exposure control is disabled during the time period before time T1, and therefore no exposure changes are made. From time T1, when a change in imaging settings is detected, to time T2, automatic exposure control is enabled, and the exposure is automatically changed so that ΔY falls within the acceptable exposure range. When ΔY falls within the acceptable exposure range at time T2, automatic exposure control is disabled. After time T2, no change in imaging settings is detected, and therefore no exposure changes are performed.

[0046] As described above, according to the exposure control of the first embodiment, the exposure tolerance range is switched according to the change in imaging settings, and the automatic exposure control is switched on or off according to the comparison result between the subject's metering value and the exposure tolerance range. This makes it possible to change the exposure when necessary while minimizing exposure fluctuations.

[0047] <Second Embodiment> In the first embodiment, the frequency of exposure changes is reduced by determining whether automatic exposure control is enabled or disabled based on changes in the imaging settings. On the other hand, even when the imaging settings do not change, there are cases where exposure control is desired if the exposure deviates significantly from the target exposure value. Therefore, in the second embodiment, an example is described in which the exposure tolerance range is changed when a change in imaging settings is detected while performing automatic exposure control, and also when the exposure tolerance range is changed while maintaining a certain range from the target exposure value even when the imaging settings do not change.

[0048] Figure 5 is a flowchart of exposure control according to the second embodiment. Each process (step) indicated by the number S in the flowchart of Figure 5 is realized by the system control unit 50 loading and executing a program stored in the non-volatile memory 56 into the system memory 52 to control the operation of each part of the imaging device 100. Figure 6 is a diagram showing the relationship between elapsed time, photometric value, and target value in exposure control according to the second embodiment when the imaging environment changes as shown in Figure 3. Note that the block configuration of the imaging device 100 is the same as in Figure 1, so the explanation is omitted.

[0049] Since the processes S501 to S508 are the same as the processes S201 to S208 in the flowchart of Figure 2, their explanation will be omitted. If the system control unit 50 determines that the photometric value is not within the exposure tolerance range (NO in S508), it proceeds to S509. If it determines that the photometric value is within the exposure tolerance range (YES in S508), it terminates this process without changing the exposure.

[0050] In S509, the system control unit 50 determines the exposure parameters. The processes in S509 and S510 are the same as the processes in S212 and S203 of the flowchart in Figure 2, so their explanation is omitted. The process ends in S510.

[0051] The processing in S508-S509 will be explained by applying it to Figure 6. In Figure 6, the exposure tolerance range is maintained at a wide range during the time period before time T3, and the magnitude of ΔY is permitted within the exposure tolerance range. During the time period from T3 to T4, when a change in the imaging settings is detected, the exposure tolerance range narrows, and the exposure is controlled so that ΔY falls within the narrow exposure target value range. At time T4, no change in the imaging settings is detected, and accordingly, control to expand the exposure tolerance range is started. Here, no change in imaging settings is detected after time T4, the exposure tolerance range reaches its maximum range at time T5, and the exposure tolerance range is maintained at its maximum range during the time period thereafter, thereby keeping the frequency of exposure changes low.

[0052] As described above, according to the exposure control of the second embodiment, when the imaging settings do not change, the exposure tolerance range can be set wide, allowing the difference between the target exposure value and the metered value to remain within a certain range while still expressing changes in the brightness of the subject. When the imaging settings change, the exposure tolerance range can be narrowed, and exposure control can be performed to reduce the difference between the target exposure value and the metered value, thereby bringing the exposure closer to a more appropriate state in response to changes in imaging settings. In this way, by changing the exposure tolerance range according to whether or not the imaging settings have changed, and performing exposure control within the changed exposure tolerance range, the frequency of exposure changes can be reduced.

[0053] Although the present invention has been described in detail above based on its preferred embodiments, the present invention is not limited to these specific embodiments, and various forms that do not depart from the spirit of the invention are also included in the present invention. Some of the embodiments described above may be combined as appropriate. For example, although the present invention was described using a digital video camera as an example in the above embodiments, the present invention can be used as a video recording function in a digital still camera or as a video recording function in a portable electronic device equipped with an imaging function such as a smartphone. [Explanation of Symbols]

[0054] 22 Imaging Department 24 Image Processing Unit 50 System Control Unit 100 Imaging device 103 Imaging lens 104 ND filter

Claims

1. A photometering means for detecting the brightness of a subject, A means for acquiring imaging settings during imaging, A setting means for setting an exposure tolerance range that allows deviation from the target exposure value, It includes an exposure control means that automatically controls the exposure during imaging, The setting means, in the imaging of video recording, changes the exposure tolerance range from a first range to a second range that is narrower than the first range when the imaging settings acquired by the acquisition means change. The exposure control means is characterized in that, during video recording, the exposure is changed when the brightness of the subject falls outside the acceptable exposure range.

2. The imaging apparatus according to claim 1, further comprising a detection means for detecting changes in the imaging settings.

3. The system further includes a comparison means for comparing the brightness of the subject with the exposure tolerance range. The imaging apparatus according to claim 1 or 2, characterized in that the exposure control means changes the exposure based on the comparison result by the comparison means.

4. The imaging apparatus according to any one of claims 1 to 3, characterized in that the minimum range of the exposure tolerance range is wider than the control tolerance range which depends on the resolution of the controlled object and the control error in the automatic exposure control by the exposure control means.

5. The imaging apparatus according to any one of claims 1 to 4, characterized in that the exposure control means changes the exposure by changing at least one of the aperture value, shutter speed, ISO sensitivity, and ND.

6. The imaging apparatus according to any one of claims 1 to 5, characterized in that the imaging settings include at least one of WB gain, ND filter density, and imaging scene.

7. The system further includes a switching means for switching between enabling and disabling automatic exposure control by the exposure control means, The imaging apparatus according to any one of claims 1 to 6, characterized in that the switching means switches between enabling and disabling the automatic exposure control based on the change in the imaging settings.

8. A method for controlling an imaging device, A photometric step that detects the brightness of the subject, The acquisition step involves obtaining the imaging settings at the time of imaging, A setting step to set an exposure tolerance range that allows deviation from the target exposure value, It includes an exposure control step that automatically controls the exposure during imaging, In the setting step, when capturing video footage, if the imaging settings acquired in the acquisition step change, the exposure tolerance range is changed from a first range to a second range that is narrower than the first range. The method for controlling an imaging device is characterized in that, in the exposure control step, the exposure is changed when the brightness of the subject falls outside the acceptable exposure range during video recording.

9. A program that causes a computer to execute each step of the control method for the imaging device described in claim 8.

Images