Imaging device and control method thereof

Abstract

This invention provides an imaging device that can reduce the effects of flicker by using an optimal shutter mode under flickering light sources. [Solution] The imaging device comprises an imaging means, a setting means capable of setting a first shooting mode and a second shooting mode different from the first shooting mode, a detection means for detecting flicker, which is a periodic change in the amount of light of a subject, a lens information acquisition means for acquiring information about a lens attached to the imaging device, a shooting parameter acquisition means for acquiring shooting parameters of the imaging device, and a calculation means for calculating optical characteristics using the lens information and the shooting parameters. The setting means sets the second shooting mode if the shooting parameters and the frequency of the flicker do not satisfy predetermined conditions, and sets the first shooting mode if the shooting parameters and the frequency of the flicker satisfy predetermined conditions and the optical characteristics are equal to or greater than the first value.

Description

Technical Field

[0001] The present invention relates to a technique for performing imaging in an imaging device typified by a digital camera, particularly reducing the influence of external light changes (generally called flicker) caused by a fluorescent lamp or the like that occurs during imaging.

Background Art

[0002] In an imaging device equipped with a mechanical shutter and an electronic shutter, an imaging device has been proposed that automatically switches to an appropriate shutter mode in consideration of the shooting environment, shooting settings, attachments to the shooting device, and the like.

[0003] In Patent Document 1, in order to suppress image blur due to shutter shock, the shutter mode is automatically switched in consideration of the shutter speed, the presence or absence of a tripod attachment, and the like.

[0004] Also, in Patent Document 2, in order to suppress image blur due to shutter shock, the shutter mode is automatically switched in consideration of the presence or absence of a macro lens attachment, the ON / OFF of the lens anti-shake function, the aperture value, and the like.

[0005] Conventionally, when imaging is performed in an environment where a fluorescent lamp is arranged, a phenomenon (flicker) occurs in which a subject corresponding to its driving frequency flickers in the captured image. More specifically, since a fluorescent lamp is driven at a commercial power frequency of 50 / 60 Hz, the light quantity change cycle of flicker due to the fluorescent lamp appears limited to 100 / 120 Hz.

[0006] In recent years, the number of light sources of light-emitting diodes (hereinafter, LEDs) has been increasing. In an LED, the method of supplying current is different from that of a fluorescent lamp, and since the driving current is controlled by a rectifier circuit, flickering occurs at a different period and a different waveform from the power frequency. Also, an LED is a light source that flickers at a faster period than a fluorescent lamp (hereinafter, referred to as a high-frequency flicker light source).

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-129230 [Patent Document 2] Japanese Patent Publication No. 2013-123248 [Overview of the project] [Problems that the invention aims to solve]

[0008] To suppress the effects of high-frequency flicker in captured images, it is preferable to change the shutter speed and shutter mode in the imaging device to an appropriate setting. However, prior art documents 1 and 2 do not disclose any methods for automatic switching to suppress the effects of high-frequency flicker. Furthermore, it is difficult for users to understand the characteristics of each shutter mode and to appropriately switch shutter modes while considering the relationship between the flickering period of the light source and the shutter speed.

[0009] The present invention has been made in view of the above-mentioned problems, and its objective is to provide an imaging device that can reduce the effects of flicker by using an optimal shutter mode under a flicker light source. [Means for solving the problem]

[0010] To achieve the above objective, an imaging device in one aspect of the present invention includes: an imaging means; a setting means capable of setting a first shooting mode for performing photography by driving a mechanical shutter and a second shooting mode for performing photography using the electronic shutter function of the imaging means; a detection means for detecting flicker, which is a periodic change in the amount of light of a subject; a lens information acquisition means for acquiring information about a lens attached to the imaging device; a shooting parameter acquisition means for acquiring shooting parameters of the imaging device; and a calculation means for calculating optical characteristics using the lens information and the shooting parameters, wherein the setting means sets the second shooting mode when the shooting parameters and the frequency of the flicker do not satisfy predetermined conditions, and sets the first shooting mode when the shooting parameters and the frequency of the flicker satisfy predetermined conditions and the optical characteristics are equal to or greater than a first value. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an imaging device that can reduce the effects of high-frequency flicker by taking pictures with an optimal shutter mode under a flicker light source. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the system configuration of a digital mirrorless camera in an embodiment of the present invention. [Figure 2] This is a flowchart of the control for selecting the shutter mode in an embodiment of the present invention. [Figure 3] This is a flowchart for calculating the luminous flux diameter in an embodiment of the present invention. [Figure 4] This figure shows the luminous flux diameter in an embodiment of the present invention. [Modes for carrying out the invention]

[0013] The present invention will be described in detail below with reference to the attached drawings, based on exemplary embodiments thereof. Note that the following embodiments do not limit the invention to the claims. Furthermore, while multiple features are described in the embodiments, not all of them are essential to the invention, and the multiple features may be combined arbitrarily. In addition, in the attached drawings, the same or similar configurations are given the same reference numeral, and redundant descriptions are omitted.

[0014] In the following embodiments, the present invention will be described in relation to cases where it is implemented using an imaging device that is a digital camera or a digital video camera. However, the present invention can be implemented with any electronic device having an imaging function. Such electronic devices include computer equipment (personal computers, tablet computers, media players, PDAs, etc.), mobile phones, smartphones, game consoles, robots, drones, dashcams, etc. These are examples, and the present invention can be implemented with other electronic devices.

[0015] <Functional Configuration of a Digital Mirrorless Camera> Figure 1 is a block diagram showing the functional configuration of the camera body 100, which is a digital mirrorless camera according to this embodiment. Note that one or more of the functional blocks shown in Figure 1 may be implemented by hardware such as an ASIC or a programmable logic array (PLA). Alternatively, they may be implemented by a programmable processor (microprocessor, microcomputer) such as a CPU or MPU executing software. Furthermore, they may be implemented by a combination of software and hardware. Therefore, even if different functional blocks are described as the primary operating components in the following description, the same hardware may be the primary implementing component.

[0016] First, let's explain the various parts that make up the camera body 100. The camera body 100 is equipped with a frame memory (not shown), which functions as a memory unit that can temporarily store signals (video signals) and read them out when needed. Generally, frame memory is also called RAM, and in recent years, DDR3-SDRAM (DUAL DATA RATE 3-SYNCHRONOUS DYNAMIC RAM) is often used. Various processing becomes possible by using this frame memory.

[0017] The image sensor 101 is an imaging means that uses a charge-accumulating solid-state image sensor such as a CMOS or CCD, which can receive the light beam of a subject guided into the camera body 100 via the lens unit 110 and convert it into an electrical image signal. The image (signal) obtained using the image sensor 101 through drive control by the CPU 104, which will be described later, is handled as various image signals such as live view display, flicker detection, and captured images for recording. Since the electrical signal obtained by the image sensor 101 is an analog value, it also has a function to convert it to a digital value. Furthermore, an evaluation value (photometric value) related to the brightness of the subject can be detected based on the image signal output from the image sensor 101. In addition, the exposure time of the image sensor 101 can be controlled according to the shutter speed, which can be set as an exposure control value related to the image sensor 101.

[0018] The mechanical shutter 102 is a light-shielding means that can travel in a direction parallel to the signal scanning direction of the image sensor 101. The exposure time of the image sensor 101 can be controlled by adjusting the exposure aperture formed by the multiple shutter blades of the mechanical shutter according to the shutter speed described above. The adjustment of the exposure time according to the present invention can be achieved by using or using in combination the so-called electronic shutter, which is achieved by adjusting the signal reset and readout timing of the image sensor 101, and the mechanical shutter 102.

[0019] The display unit 103 is a display device (display section) that can be visually recognized by the user, and the operating status of the camera body 100 can be confirmed. For example, the display unit 103 displays videos subjected to image processing based on the image signal of the subject, setting menus, and the like. The information displayed on the display unit 103 can be controlled by the CPU 104 described later. That is, the CPU 104 functions as display control means.

[0020] As the display unit 103, an LCD (LIQUID CRYSTAL DISPLAY) or an organic EL (ORGANIC ELECTROLUMINESCENCE) may be used. By displaying in real time on the display unit 103 an image acquired by the imaging element 101 during imaging of the subject and setting conditions such as an exposure control value, so-called live view display can be performed. Note that the display unit 103 of the present embodiment includes a resistive film type or a capacitive film element called a touch panel, and also serves as an operation unit that can be touched by the user. For example, various settings of the camera body 100 can be changed by touching an icon or a menu display displayed on the display unit 103.

[0021] The CPU 104 is control means that can comprehensively control each part of the camera body 100 and accessories attached to the camera body 100. A ROM (READ ONLY MEMORY) and a RAM (RANDOM ACCESS MEMORY) are connected to the CPU 104. The ROM (not shown) is a non-volatile recording element, and stores a program for operating the CPU 104 and various adjustment parameters. The program read from the ROM is expanded and executed in a volatile RAM (not shown). Generally, as compared with a frame memory (not shown), an element with low speed and low capacity is used for the RAM.

[0022] As an example of the functions of the CPU 104, the CPU 104 can implement an electronic shutter function by controlling the reset of each line of the image sensor 101. In addition, the CPU 104 can move the image sensor 101 between a position where it is shielded from light and a position where it is exposed by controlling the mechanical shutter 102 (mechanical shutter function).

[0023] Next, the details of the lens unit 110 will be described. The lens unit 110 is an accessory that can be attached to the camera body 100 and is a so-called interchangeable lens equipped with a group of lenses 111 such as a focus lens, a zoom lens, and a shift lens. For example, the focusing lens of the lens group 111 can adjust the focus on the subject by adjusting the lens position in the direction of the optical axis of the lens.

[0024] The aperture 112 is a light intensity adjustment member for adjusting the amount of light related to the light beam of a subject guided into the camera body 100 via the lens unit 110. In this embodiment, the amount of light can be adjusted by adjusting the aperture diameter of the aperture 112, and this is achieved by changing the aperture value as an exposure control value related to the aperture diameter.

[0025] The LPU 113 is a control means that controls various parts of the lens unit 110, and can, for example, control the drive of the lens group 111 and the aperture 112. The LPU 113 is connected to the CPU 104 of the camera body 100 via a group of terminals (not shown), and can drive various parts of the lens unit 110 in response to control instructions from the CPU 104. In addition, the LPU 113 can communicate with the CPU 104 of the camera body 100 via a group of terminals (not shown) to exchange information such as focus position and aperture with the camera body.

[0026] (Shutter mode) Next, the shutter modes that can be set in the digital mirrorless camera according to this embodiment will be described. The user can select the shutter mode from a menu screen on the display unit 103, for example. However, the direction of selection of the shutter mode is not limited to this; for example, the camera body 100 may be provided with operation buttons (not shown), and the shutter mode may be set based on operation of those buttons.

[0027] In this embodiment, the configurable shutter modes include electronic front curtain shutter mode, electronic shutter mode, mechanical shutter mode, and automatic shutter mode.

[0028] In electronic front curtain shutter mode, shutter control at the start of exposure (front curtain shutter control) is performed electronically by the image sensor 101, and shutter control at the end of light exposure (rear curtain shutter control) is performed by the shutter 102. In electronic shutter mode, both front curtain shutter control and rear curtain shutter control are performed electronically by the image sensor 101. In mechanical shutter mode, both front curtain shutter control and rear curtain shutter control are performed by the mechanical shutter 102. In automatic shutter mode, it is possible to automatically switch between implementing front curtain shutter control and rear curtain shutter control using either an electronic shutter or a mechanical shutter. When set to automatic shutter mode, in this embodiment, as will be described later, the CPU 104 uses flicker information, shooting parameters, lens information, and optical characteristics to select the shutter mode.

[0029] (Shutter mode selection) Next, with reference to the flowchart shown in Figure 2, the control for selecting the shutter mode in Embodiment 1 of the present invention will be described. In this embodiment, the shutter mode will be described assuming that the user has selected the automatic shutter mode.

[0030] First, in step S200, after the camera is powered on and while waiting for the user to perform a shooting operation, the CPU 104 controls various parts of the camera body 100 to perform flicker detection processing. As mentioned earlier, unlike fluorescent lamps and other light sources, LED light sources control the drive current with a rectifier circuit, so changes in light intensity (flickering), i.e., flicker, occur at a different frequency than the power supply frequency used to drive the light source. Therefore, when detecting flicker caused by light sources such as LEDs, it is not possible to narrow down the frequency to be detected to a specific value, as is the case with the drive power supply frequency, so it is necessary to analyze whether or not flicker occurs over a wide range of frequencies.

[0031] On the other hand, when the frequency of the flicker's light intensity change (the blinking period of the light source) matches or is an integer multiple of the imaging period when continuously imaging a subject (hereinafter referred to as synchronization), periodic changes in light intensity (blinking) between continuously obtained images are suppressed. In this case, for example, in live view display where images are displayed continuously, no degradation in image quality such as unevenness caused by flicker occurs, but still images acquired by imaging at an arbitrary shutter speed may have exposure unevenness caused by flicker. Furthermore, even if the imaging frame rate for live view display images matches the frequency of the flicker's light intensity change, if video for recording is acquired at a different frame rate, there is a risk that the video may have exposure unevenness or brightness fluctuations caused by flicker.

[0032] Here, a known method for identifying the frequency of light intensity changes in flicker is to detect and compare the difference in light intensity (brightness and darkness) in images obtained by continuous imaging. Therefore, when using this method to identify the frequency of light intensity changes in flicker, it is necessary to adjust the imaging period (frame rate) so that it does not synchronize with the frequency of light intensity changes in flicker.

[0033] Therefore, in this embodiment, for example, the method described in Japanese Patent Application Publication No. 2022-130277 (hereinafter referred to as "Patent Document 3") is used. In the method of Patent Document 3, the presence or absence of flicker can be detected by analyzing the frequency of the change in light intensity of the flicker over multiple imaging periods. With this method, by analyzing the frequency of the change in light intensity of the flicker over multiple frequencies, it is possible to avoid the synchronization of the flicker's light intensity change frequency and the imaging period, and effective detection processing can be performed even for flicker over a wide range of frequencies. Note that the method for detecting flicker is not limited to the method of Patent Document 3, and any method that can detect the presence or absence of flicker over a wide range of frequencies may be used. Once flicker detection is complete, the process proceeds to step S201.

[0034] In step S201, the CPU 104 determines, as a predetermined condition, whether the difference between the shutter speed set as a shooting parameter and an integer multiple of the flicker cycle identified in step S200 is greater than or equal to a threshold (for example, the threshold is set to 10 microseconds). If it is greater than or equal to the threshold, the predetermined condition is met and the process proceeds to step S202; if it is less than the threshold, the predetermined condition is not met and the process proceeds to step S205.

[0035] In step S202, the CPU 104 calculates the radius R1 of the light beam entering the slit 105 of the shutter 102 shown in Figure 4. The method for calculating the light beam diameter will be described later.

[0036] In step S203, the CPU 104 determines whether the radius R1 of the light beam entering the slit 105 of the shutter 102, calculated in S102, is greater than or equal to a threshold. If the radius R1 of the light beam entering the slit 105 of the shutter 102 is greater than or equal to the threshold, the process proceeds to step S204; otherwise, the process proceeds to step S205.

[0037] In step S204, the CPU 104 selects the mechanical shutter mode, and in step S205, the CPU 104 selects the electronic shutter mode. The CPU 104 controls the camera body 100 so that shooting is performed based on the selected shutter mode.

[0038] The following explains the reasons for using mechanical shutter mode and electronic shutter mode. Ideally, the light beam entering each pixel on the image sensor forms a cone with the pupil of the image sensor as the base and each pixel as the apex. The exposure amount for each pixel is controlled by cutting off this light beam by moving a wide slit, and this can be increased or decreased by changing the width of the slit and the speed at which it moves. Generally, in a single camera, it is difficult to change the speed of the electronic shutter due to the limitations of the electrical circuit, and in the mechanical shutter due to mechanical limitations such as spring force, so the exposure amount is controlled by adjusting the width of the slit.

[0039] In electronic shutter mode, exposure control is performed on the image sensor plane, while in mechanical shutter mode, exposure control is performed on a plane a certain distance away from the image sensor. Therefore, in contrast, in electronic shutter mode, each element receives light with a high peak for a short time, while in mechanical shutter mode, it receives light with a low peak for a long time. The shorter the exposure time, the more pronounced the effect that each pixel receives from a high-frequency flicker light source. As a result, the image in electronic shutter mode shows more distinct light and dark stripes than in mechanical shutter mode, and the effects of flicker are more noticeable.

[0040] Therefore, in step S203, if a reduction in flicker can be expected, the mechanical shutter mode is selected. In this embodiment, if a reduction in flicker cannot be expected, the electronic shutter, which has a faster release time lag and continuous shooting speed, is selected.

[0041] (Calculation of luminous beam diameter) Next, using Figures 3 and 4, we will explain how to calculate the radius R1 of the light beam entering the slit 105 of the shutter 102 in step S202.

[0042] Figure 3 illustrates the flow for calculating the light beam diameter. First, in step S300, the LPU 113 obtains the lens pupil position from the ROM of the LPU 113. Next, in step S301, the LPU 113 obtains the current focal length L2 of the lens unit 110. Then, in step S302, the CPU 104 obtains the aperture value F set in the aperture 112.

[0043] In step S303, the CPU 104 acquires the distance L1 between the image sensor 101 and the shutter 102. It goes without saying that the order in which the various pieces of information are acquired as shown in steps S300 to S303 is not limited to this order.

[0044] In step S304, the LPU 113 transmits the lens focal length L2 as lens information and the aperture value F and the distance L0 between the image sensor and the lens pupil as shooting parameters to the CPU 104 of the camera body 100 via a group of terminals not shown. That is, the CPU 104 functions as a means for acquiring lens information and shooting parameters (lens information acquisition means, shooting parameter acquisition means). Note that the aperture value F and the distance L0 between the image sensor and the lens pupil may be information acquired in advance by the camera body 100, for example, and do not necessarily need to be acquired via the LPU 113. For example, the aperture value set by the user can be known in advance by the camera body 100.

[0045] Based on the transmitted information, the CPU 104 calculates the radius R1 of the light beam entering the slit 105 of the mechanical shutter 102.

[0046] The radius R1 of the light beam entering the slit 105 of the shutter 102 is calculated using the following formula, where R0 is the lens pupil radius, L1 is the distance between the image sensor 101 and the slit 105 of the shutter 102, and L0 is the distance between the image sensor and the lens pupil.

[0047] [Mathematics 1] R1 = R0 × L1 ÷ L0 Furthermore, the lens pupil radius R0 can be calculated using the lens focal length L2 and aperture value F by the following formula.

[0048] [Math 2] R0 = L2 ÷ F ÷ 2 Based on the above calculation formula, the luminous flux diameter is calculated in step S202, and the determination in step S203 is made based on the calculated luminous flux diameter.

[0049] In this way, by selecting the appropriate shutter mode based on shutter speed, flicker frequency, and light beam diameter, it is possible to take photos with reduced flicker effects.

[0050] Furthermore, in step S205, if the user has selected electronic shutter mode instead of automatic shutter mode, the CPU 104 may be controlled to forcibly switch to mechanical shutter mode. Alternatively, an icon prompting the user to switch to mechanical shutter mode may be displayed on the display unit 103. The icon prompting the user to switch to mechanical shutter mode may also include information indicating the degree of flicker reduction effect.

[0051] As described above, by selecting the appropriate shutter mode based on shutter speed, flicker frequency, and light beam diameter, it is possible to take photos with reduced flicker effects.

[0052] (Variation 1) In the above-described embodiment, the mechanical shutter mode was selected in step S204, but a different shutter mode may be selected depending on the situation. For example, in scenes where the user desires high-speed continuous shooting, it is undesirable for release time lag or a decrease in continuous shooting speed to occur. Therefore, the CPU 104 may determine the shooting scene by referring to the set shooting mode and select a shutter mode based on the determination result. For example, if the CPU 104 determines that it is an undesirable shooting scene for release time lag or a decrease in continuous shooting speed to occur, instead of normally selecting the mechanical shutter mode in step S204, it may select the electronic front curtain shutter mode.

[0053] (Modification 2) As a modification of this embodiment, we will describe a control that notifies the user of a change in shooting settings that is expected to have a greater effect in reducing flicker, when the user has selected the mechanical shutter. Note that the basic configuration is the same as the practical configuration described above, so we will omit the explanation.

[0054] The radius R1 of the light beam entering the slit 105 of the mechanical shutter 102 increases as the distance L0 between the image sensor and the lens pupil decreases, the lens focal length L2 increases, and the aperture value F decreases, as shown in [Equation 1] and [Equation 2].

[0055] Therefore, the system will notify the user of shooting settings that increase the radius R1 of the light beam entering the slit 105 of the shutter 102, depending on the current shooting settings and lens condition.

[0056] Examples of notifications include displaying an icon on the display unit 103 prompting the user to decrease the aperture value F. Additionally, if a lens unit 110 with a variable focal length L2 is attached to the camera body 100, displaying an icon on the display unit 102 prompting the user to increase the lens's focal length L2.

[0057] As described above, by notifying users of changes to shooting settings that have a greater flicker reduction effect, we encourage users to set shooting conditions that can reduce the effects of flicker. This allows us to provide users with more opportunities to take photos with reduced flicker effects.

[0058] (Other embodiments) Furthermore, the present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0059] 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. Furthermore, the disclosure of this embodiment includes the following imaging device and control method.

[0060] (Configuration 1) An imaging device comprising: an imaging means; a setting means capable of setting a first shooting mode for performing photography by driving a mechanical shutter and a second shooting mode for performing photography using the electronic shutter function of the imaging means; a detection means for detecting flicker, which is a periodic change in the amount of light of a subject; a lens information acquisition means for acquiring information about a lens attached to the imaging device; a shooting parameter acquisition means for acquiring shooting parameters of the imaging device; and a calculation means for calculating optical characteristics using the lens information and the shooting parameters, wherein the setting means sets the second shooting mode when the shooting parameters and the frequency of the flicker do not satisfy predetermined conditions, and sets the first shooting mode when the shooting parameters and the frequency of the flicker satisfy predetermined conditions and the optical characteristics are equal to or greater than a first value.

[0061] (Configuration 2) The imaging device according to Configuration 1, characterized in that the optical characteristic is the diameter of the light beam that enters the position of the slit of the mechanical shutter.

[0062] (Configuration 3) The imaging device according to Configuration 1 or 2, characterized in that the lens information is the pupil position, focal length, and aperture value of the lens.

[0063] (Configuration 4) An imaging device according to any one of Configurations 1 to 3, characterized in that at least one of the shooting parameters is shutter speed.

[0064] (Configuration 5) An imaging device according to any one of Configurations 1 to 4, characterized in that the difference between the shutter speed and an integer multiple of the flicker cycle is smaller than the first value for the predetermined conditions of the shooting parameters and the flicker frequency.

[0065] (Configuration 6) An imaging device according to any one of Configurations 1 to 5, characterized in that the first shooting mode has an electronic shutter for the front curtain and a mechanical shutter for the rear curtain, and the second shooting mode has an electronic shutter for the front curtain and an electronic shutter for the rear curtain.

[0066] (Configuration 7) An imaging device according to any one of Configurations 1 to 6, wherein the device has a display control means for controlling the display of a display unit, and when the second shooting mode is selected, if the shooting parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are equal to or greater than a first value, the display control means displays information on the display unit prompting the user to switch to the first shooting mode.

[0067] (Configuration 8) An imaging device according to any one of Configurations 1 to 6, characterized in that it has a notification means for notifying the degree of the flicker reduction effect when the first shooting mode is selected.

[0068] (Configuration 9) An imaging device according to any one of Configurations 1 to 6, characterized in that when the first shooting mode is selected, the imaging parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are greater than or equal to a first value, the device has a notification means that notifies information prompting the user to increase the focal length of the lens.

[0069] (Configuration 10) An imaging device according to any one of Configurations 1 to 6, characterized in that when the first shooting mode is selected, the imaging parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are greater than or equal to a first value, the imaging device has a notification means that notifies information prompting the user to reduce the aperture value of the imaging device.

[0070] (Method 1) A method for controlling an imaging device, comprising: an imaging step; a setting step for setting an imaging mode, a first shooting mode for performing photography by driving a mechanical shutter, and a second shooting mode for performing photography using the electronic shutter function of the imaging means; a detection step for detecting flicker, which is a periodic change in the amount of light of a subject; a lens information acquisition step for acquiring information about a lens attached to the imaging device; a shooting parameter acquisition step for acquiring shooting parameters of the imaging device; and a calculation step for calculating optical characteristics using the lens information and the shooting parameters, wherein in the setting step, if the shooting parameters and the frequency of the flicker do not satisfy predetermined conditions, the second shooting mode is set, and if the shooting parameters and the frequency of the flicker satisfy predetermined conditions and the optical characteristics are equal to or greater than a first value, the first shooting mode is set. [Explanation of Symbols]

[0071] 100 Camera Body 101 Image sensor 102 Shutter 103 Display Unit 104 CPU 105 slits 110 Lens Unit 111 lens group 112 aperture 113 LPU

Claims

1. An imaging device, Imaging means, A setting means that can set a first shooting mode in which a mechanical shutter is driven to take a picture, and a second shooting mode in which the electronic shutter function of the imaging means is used to take a picture. A detection means for detecting flicker, which is a periodic change in the light intensity of a subject, A lens information acquisition means for acquiring information about the lens attached to the imaging device, A means for acquiring imaging parameters of the imaging device, It has a calculation means for calculating optical characteristics using the lens information and the shooting parameters, The setting means sets the second shooting mode if the shooting parameters and the flicker frequency do not meet predetermined conditions, and sets the first shooting mode if the shooting parameters and the flicker frequency meet predetermined conditions and the optical characteristics are equal to or greater than the first value. An imaging device characterized by the following features.

2. The imaging apparatus according to claim 1, characterized in that the optical characteristic is the diameter of the light beam that enters the position of the slit of the mechanical shutter.

3. The imaging device according to claim 2, characterized in that the lens information is the pupil position, focal length, and aperture value of the lens.

4. The imaging apparatus according to claim 1, characterized in that at least one of the aforementioned shooting parameters is shutter speed.

5. The imaging apparatus according to claim 1, characterized in that the difference between the shutter speed and an integer multiple of the flicker cycle is smaller than a first value for the predetermined conditions of the shooting parameters and the flicker frequency.

6. The imaging device according to claim 1, characterized in that the first shooting mode has an electronic shutter for the front curtain and a mechanical shutter for the rear curtain, and the second shooting mode has an electronic shutter for the front curtain and an electronic shutter for the rear curtain.

7. It has a display control means for controlling the display unit, The imaging device according to claim 1, characterized in that, when the second shooting mode is selected, if the shooting parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are equal to or greater than the first value, information prompting the user to switch to the first shooting mode is displayed on the display unit.

8. The imaging device according to claim 1, characterized in that it has a notification means for notifying the degree of the flicker reduction effect when the first shooting mode is selected.

9. The imaging device according to claim 1, characterized in that, when the first shooting mode is selected, the imaging parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are greater than or equal to a first value, the device has a notification means that notifies the user of information prompting the user to increase the focal length of the lens.

10. The imaging device according to claim 1, characterized in that, when the first shooting mode is selected, the imaging parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are greater than or equal to a first value, the imaging device has a notification means that notifies information prompting the user to reduce the aperture value of the imaging device.

11. A method for controlling an imaging device, Imaging step, A setting step for setting a first shooting mode in which a mechanical shutter is driven to take a picture, and a second shooting mode in which the electronic shutter function of the imaging means is used to take a picture. A detection step that detects flicker, which is a periodic change in the amount of light in the subject, A lens information acquisition step to acquire information about the lens attached to the imaging device, A step of acquiring imaging parameters for the imaging device, The system includes a calculation step of calculating optical characteristics using the lens information and the shooting parameters, A method for controlling an imaging device, characterized in that, in the setting step, if the shooting parameters and the flicker frequency do not satisfy predetermined conditions, the second shooting mode is set, and if the shooting parameters and the flicker frequency satisfy predetermined conditions and the optical characteristics are equal to or greater than the first value, the first shooting mode is set.

Images