JP7370875B2 - Imaging device and its control method - Google Patents

Description

The present invention relates to an imaging device and a control method thereof.

When a lighting device (so-called strobe device) built into or attached to an imaging device emits light, a certain amount of time is required for a charging operation to store the energy necessary for light emission. Therefore, even if the photographer performs a release operation at the intended timing (so-called photo opportunity), the illumination device may not emit light due to insufficient charging, and it may not be possible to capture an image. To address this problem, for example, Patent Document 1 discloses that when a photographer performs a release operation, even if the predetermined amount of light emission cannot be obtained because the predetermined charge level has not been reached, the illumination device is activated to take an image. Discloses technology to do this.

Japanese Patent Application Publication No. 3-77929

However, the above-mentioned Patent Document 1 does not mention automatic light control operation accompanied by pre-light emission. With automatic flash control, a pre-flash is performed to measure the reflected light from the subject, the main flash amount is calculated to achieve the correct exposure, and the main flash is used during the main image capture to achieve the appropriate exposure. do. Therefore, if automatic dimming control is performed at a charge level below a predetermined charge level, only pre-light emission may be performed, and a state in which main light emission may not be performed may continue. In this case, only the energy for pre-light emission will continue to be consumed, and as a result, there is a possibility that more shutter opportunities will be missed than in conventional light emission control.

The present invention provides an imaging device that is capable of reducing the possibility that an image with insufficient main flash amount deviates from the proper exposure when automatic light adjustment is performed in flash photography that allows flash emission regardless of the charge level. The purpose is to provide

The imaging device according to the present invention includes a light emitting section that irradiates light to a subject when an image is captured by an imaging means, a charging section that supplies energy for emitting light to the light emitting section, and a charging section that causes the light emitting section to perform pre-light emission to capture the image. a light control means for determining a main light emission amount when causing the light emitting unit to emit light during main imaging based on an image acquired by the imaging means; and a light control unit for obtaining the main light emission amount determined by the light control means during main imaging. a setting means for setting a light emission mode in which the light emitting section is caused to emit light even when the charge level is such that the light emitting section cannot emit light; After the number of times that the main light emission amount determined by the light control means has not been obtained reaches a predetermined number of times, the main light emission amount is changed by the light control means only when the current charging section is at a predetermined charge level or higher. The present invention is characterized by comprising: a control means for executing light emission control to determine the main light emission and perform main light emission.

According to the present invention, when automatic light adjustment is performed in light emission photography in which light emission is permitted regardless of the charge level, it is possible to reduce the possibility that images taken with an insufficient amount of main light emission deviate from the proper exposure.

1 is a block diagram showing a schematic configuration of an imaging device according to an embodiment of the present invention. 5 is a flowchart of control in strobe photography according to the first embodiment. 7 is a flowchart illustrating pre-light emission control in the strobe device in the first embodiment. 5 is a flowchart illustrating main light emission control in the strobe device in the first embodiment. 7 is a flowchart of control performed by the camera control unit when a change occurs in the mounting state of the strobe device on the camera body in the first embodiment. 7 is a flowchart of control in strobe photography according to the second embodiment. 7 is a flowchart illustrating pre-light emission control in a strobe device in a second embodiment. 7 is a flowchart illustrating main light emission control in a strobe device in a second embodiment. 5 is a flowchart of control performed by the strobe control unit when a change occurs in the mounting state of the strobe device on the camera body in the first embodiment.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In this embodiment, an image capturing apparatus is adopted in which a lens and an illumination device are detachable from the image capturing apparatus main body.

FIG. 1 is a block diagram showing a schematic configuration of an imaging apparatus 1000 according to an embodiment of the present invention. The imaging device 1000 is a so-called digital single-lens reflex camera, and includes an imaging device main body 100 (hereinafter referred to as "camera body 100"), a lens 200, and a lighting device 300 (hereinafter referred to as "stroboscopic device 300").

The camera body 100 includes a camera control section 101, an image sensor 102, a mount contact group 103, a shutter 104, a camera operation section 105, a camera display section 106, an image storage section 107, and a strobe contact group 109. The lens 200 includes a lens control section 201, an imaging lens 202, and an aperture 203. The strobe device 300 includes a strobe control section 301, a light emitting section 302, a strobe operation section 303, a strobe display section 304, a charging section 305, and a photocurrent detection section 306.

The lens 200 is removably attached to the camera body 100. Further, the strobe device 300 is an external lighting device that can be attached to and detached from an accessory shoe (not shown) provided on the camera body 100. The camera body 100 and the lens 200 are electrically connected via a mount contact group 103. Further, the camera body 100 and the strobe device 300 are electrically connected via a strobe contact group 109.

The camera control unit 101 of the camera body 100 is a microcomputer that centrally controls the operation of the entire imaging device 1000. The imaging device 102 converts incident light from the imaging lens 202 into an electrical signal, generates image data, and outputs the image data to the camera control unit 101. The shutter 104 is disposed between the image pickup element 102 and the image pickup lens 202, and operates according to instructions from the camera control unit 101. The shutter 104 is, for example, a focal plane shutter composed of a front curtain and a rear curtain. Exposure to the image sensor 102 is started when the front curtain runs and the shutter opens, and when the rear curtain runs and the shutter closes. Exposure of the image sensor 102 is ended.

The camera operation unit 105 includes buttons, switches, dials, etc. for starting an imaging operation, changing and setting imaging conditions, etc., and sends a signal according to an operation instruction to the camera control unit 101. Further, the camera operation unit 105 detects an operation performed by the photographer via a connected device or the like, and sends a signal corresponding to the operation instruction to the camera control unit 101.

The camera operation unit 105 has a release button for instructing the start of an imaging operation. When the release button is pressed halfway, a SW1 signal is output to the camera control unit 101, and when the release button is pressed fully, a SW2 signal is output to the camera control unit 101. When the camera control unit 101 receives the SW1 signal, it starts an imaging preparation operation (AE operation, AF operation, etc.), and when it receives the SW2 signal, it starts an imaging operation (exposure operation).

The camera display unit 106 displays a subject image during image capture, setting information for the camera body 100 and the strobe device 300, and reproduces and displays captured images. Note that display control on the camera display section 106 is performed by the camera control section 101.

The camera control section 101 controls the operation of the camera body 100 based on the output signal from the camera operation section 105. When the SW1 signal is output from the camera operation unit 105, the camera control unit 101 drives the image sensor 102 to obtain an optical image of the subject (subject image), and uses the image data of the obtained optical image to determine the brightness of the subject. Repeat photometry control (AE operation) to measure Furthermore, the camera control unit 101 determines the shutter speed, aperture value, and ISO sensitivity to be used during actual imaging based on the photometry results. In the following description, the shutter speed, aperture value, and ISO sensitivity used during imaging are collectively referred to as an exposure control value. The determined exposure control value is displayed on the display screen (eg, liquid crystal panel) of the camera display unit 106.

When the SW2 signal is output from the camera operation unit 105, the camera control unit 101 drives the aperture 203 in the imaging lens 202, sets the sensitivity (ISO sensitivity) of the imaging element 102, and controls the shutter 104 to capture an image. The element 102 is irradiated with incident light. The camera control unit 101 displays a photographed image on the screen of the camera display unit 106 according to the image data acquired from the image sensor 102, and controls writing of the image data into the image storage unit 107.

In the lens 200, the lens control unit 201 is a microcomputer that controls the operation of each part of the lens 200. The imaging lens 202 is composed of a plurality of lenses, and forms a subject image on the imaging element 102. Note that the imaging lens 202 includes a focus lens (not shown) for adjusting focus. Aperture 203 adjusts the amount of incident light. The lens control unit 201 adjusts the amount of light taken into the camera body 100 and the focus according to instructions received from the camera control unit 101 via the mount contact group 103.

In the strobe device 300, the strobe control unit 301 is a microcomputer that controls the operation of each part of the strobe device 300. The strobe control unit 301 communicates with the camera control unit 101 via the strobe contact group 109, receives light emission control instructions and camera information from the camera control unit 101, and can also transmit strobe information to the camera control unit 101. can.

The charging unit 305 uses power supplied from a battery (not shown) mounted on the strobe device 300 to perform a charging operation to store energy in a light emitting capacitor (not shown) to generate light to be irradiated to a subject. I do. In the following description, charging the light emitting capacitor will be referred to as "strobe charging."

Strobe charging is controlled by a strobe control unit 301. At this time, the strobe control unit 301 detects the charging voltage of the light emitting capacitor (hereinafter referred to as "strobe charging voltage"), and when the strobe charging voltage reaches a predetermined voltage threshold, it determines that strobe charging is completed. Stop strobe charging and update the charging completion flag. In other words, the predetermined voltage threshold is a value for stopping strobe charging when it becomes possible to irradiate a subject with a desired amount of light emission. Further, the strobe control unit 301 starts strobe charging when the strobe charging voltage becomes smaller than a predetermined voltage threshold. The strobe charging voltage and charging completion flag are transmitted to the camera control unit 101 via the strobe contact group 109.

The flash operation unit 303 includes operation members such as buttons and dials operated by the photographer, and detects operations performed by the photographer on the operation members and sends a signal according to the operation instruction to the flash control unit 301. send. The strobe display section 304 displays the light emission mode and the like. Note that display control on the strobe display section 304 is performed by the strobe control section 301.

The light emitting section 302 includes a discharge tube, a light emitting circuit, and a light emitting optical system. The light emitting unit 302 drives a light emitting circuit according to instructions from the strobe control unit 301, emits light by releasing energy stored in a light emitting capacitor into a discharge tube, and irradiates light onto a subject via a light emitting optical system. The amount of light emitted from the light emitting section is monitored by the strobe controller 301 via the photocurrent detection section 306, and when a predetermined amount of light is detected, the light emission is stopped. The photocurrent detection unit 306 includes a light receiving diode and a circuit that integrates the current generated from the light receiving diode and converts it into a voltage. The strobe control unit 301 determines whether a predetermined amount of light has been emitted toward the subject by comparing the photocurrent or its integrated voltage with a predetermined threshold. Note that a configuration may be adopted in which the amount of light emission is set using the strobe operation unit 303. Further, the amount of light emitted may be obtained through communication from the camera control unit 101 via the strobe contact group 109.

The strobe control unit 301 receives a control signal from the camera control unit 101 via the strobe contact group 109, and causes the light emitting unit 302 to emit light with a predetermined amount of light in synchronization with the imaging operation of the camera body 100.

<First embodiment>
In the first embodiment, it is assumed that the imaging device 1000 can set the light emission mode of the strobe device 300 during image capturing to a "release priority light emission mode" or a "light amount priority light emission mode." The release priority light emission mode is a mode that prioritizes the imaging operation over the strobe charging state, and is a mode in which strobe photography is performed according to the release operation even if the strobe charging is insufficient. On the other hand, "Light Priority Flash Mode" is a mode that prioritizes the strobe charging state over the imaging operation, and only when the charging level is above a predetermined threshold (the desired flash amount can be obtained), the strobe will fire according to the release operation. This is the mode for taking pictures.

The strobe device 300 (strobe control unit 301) holds as setting information whether the set light emission mode is the release priority light emission mode or the light amount priority light emission mode. It is assumed that the switching and setting of the light emission mode in the strobe device 300 is determined by the photographer's operation of the strobe operation unit 303. However, the present invention is not limited to this, and the setting of the light emission mode is performed by the photographer operating the camera operation unit 105 to determine the light emission mode, and transmitting the operation information to the strobe device 300. Good too.

Further, in the first embodiment, it is assumed that automatic light control mode is set. In the automatic light control mode, a pre-flash is emitted for the subject, and an appropriate light emission amount (main light emission amount) for the main image capturing is calculated based on the result of the reflected light from the subject being received by the image sensor 102. Actual imaging with exposure is executed.

FIG. 2 is a flowchart illustrating control in strobe photography according to the first embodiment by the imaging apparatus 1000. Each process (step) indicated by an S number in the flowchart of FIG. 2 is realized by the camera control unit 101 executing a predetermined program to collectively control the operation of each unit of the imaging apparatus 1000. The flowchart in FIG. 2 is based on continuous flash photography in which strobe photography is performed continuously, and "end" in the flowchart indicates the end of capturing one image.

In S200, the camera control unit 101 determines whether the SW1 signal is turned on. If the camera control unit 101 determines that the SW1 signal remains off (NO in S200), repeats the determination in S200 (wait until SW1 turns on), and if it determines that the SW1 signal is turned on. (YES in S200), the process advances to S201.

In S201, the camera control unit 101 acquires strobe information from the strobe device 300. The flash information acquired by the camera control unit 101 in S201 includes information indicating whether the flash device 300 is set to the release priority flash mode or the light amount priority flash mode, and information indicating the flash charging state.

In S202, the camera control unit 101 determines whether the flash device 300 is set to the release priority light emission mode. Here, it is assumed that the strobe device 300 is set to the light amount priority light emission mode if it is not set to the release priority light emission mode. If the camera control unit 101 determines that the release priority flash mode is set (YES in S202), the process proceeds to S204, and if it determines that the light amount priority flash mode is set (NO in S202), The process advances to S203.

In S203, the camera control unit 101 determines whether strobe charging is completed based on the information obtained from the strobe device 300. In S203, it is determined that strobe charging is complete when the charging voltage of the light emitting capacitor is equal to or higher than a predetermined voltage threshold (voltage threshold for stopping strobe charging). If the camera control unit 101 determines that strobe charging has been completed (YES in S203), the process proceeds to S204, and if it determines that strobe charging has not been completed (NO in S203), the process proceeds to S205. Proceed. Note that the strobe control unit 301 may determine whether or not strobe charging is completed. In this case, for example, the camera control unit 101 receives a charging completion flag from the strobe device 300.

In S204, the camera control unit 101 performs AE operation for strobe photography, since it is possible to emit strobe light regardless of the charging state or to emit strobe light at a predetermined amount of light emission, and then advances the process to S206. . On the other hand, in S205, the camera control unit 101 performs an AE operation for normal photography without strobe light emission because it is determined in S203 that strobe light emission with the desired amount of light emission is not guaranteed, and then performs processing. Proceed to S206.

Note that the AE operation is a process of calculating the brightness of the subject area from the signal output from the image sensor 102 and determining exposure parameters during actual imaging. Exposure parameters include ISO sensitivity, shutter speed, and lens aperture value. In the AE operation in S204, exposure parameters are determined on the premise that the strobe device 300 will emit light during the main imaging. On the other hand, in the AE operation in S205, exposure parameters are determined on the premise that the strobe device 300 does not emit light during the main imaging. For example, in order to avoid overexposure (saturation of the image sensor 102) in the captured image due to the light emitted from the strobe device 300, the upper limit of the ISO sensitivity in S204 is set to a value lower than the ISO sensitivity in S205. is set to

In S206, the camera control unit 101 determines whether the SW2 signal is turned on. If the camera control unit 101 determines that the SW2 signal is turned on (YES in S206), the process proceeds to S207, and if it determines that the SW2 signal is not turned on (NO in S206), the process returns to S201. Then, the processes of S201 to S206 are repeated.

In S207, the camera control unit 101 determines whether the flash mode set in the flash device 300 is the release priority flash mode based on the flash information. If the camera control unit 101 determines that the release-priority light emission mode is set (YES in S207), the process proceeds to S209, and if it determines that the release-priority light emission mode is not set (NO in S207), The process advances to S208.

In S208, since the strobe device 300 is set to the light amount priority emission mode, the camera control unit 101 checks the strobe charging state based on the strobe information and determines whether strobe charging is completed. The determination method in S208 is the same as the determination method in S203. If the camera control unit 101 determines that strobe charging has been completed (YES in S208), the process proceeds to S209, and if it determines that strobe charging has not been completed in S208 (NO in S208), the camera control unit 101 continues the process. Proceed to S221. Note that when the process proceeds from S208 to S209, sufficient energy is supplied to the light emission capacitor so that the subsequent pre-emission amount does not become smaller than the pre-emission amount threshold and the main emission amount does not become smaller than the main emission amount threshold. Strobe device 300 is designed to be recharged.

In S209, the camera control unit 101 determines a predetermined number of times the pre-flash could be performed but the main flash could not be performed because the light emission amount was equal to or higher than the main flash amount threshold (hereinafter referred to as the "main flash failure number"). Determine whether or not the number of times is greater than or equal to the number of times. If the camera control unit 101 determines that the number of main flash failures is greater than or equal to the predetermined number of times (YES in S209), the camera control unit 101 advances the process to S210, and if it determines that the number of main flash failures is less than the predetermined number of times (NO in S209). ), the process advances to S211.

In S210, the camera control unit 101 acquires strobe information from the strobe control unit 301. The information acquired by the camera control unit 101 in S210 includes the current charging level of the strobe device 300. Therefore, in S210, the camera control unit 101 determines that the current charging level of the strobe device 300 is such that the pre-flash has been executed but the main flash amount is less than the main flash amount threshold (hereinafter referred to as "main flash failure"). It is determined whether the charge level is higher than or equal to the maximum charge level.

Note that even if it is possible to perform pre-light emission, if main light emission cannot be performed with the desired amount of light emission, the charging energy used for pre-light emission will be wasted. Therefore, in the light emission control in this embodiment, when the number of main light emission failures exceeds a predetermined number and the charge level is less than a predetermined charge level, light emission control is not performed (pre-flash and main light emission are not performed). will not be carried out). In this way, the predetermined charge level that serves as a criterion for determining whether to perform light emission control (control after S211) is the maximum charge level when main light emission fails, and is set in S220, which will be described later.

When the camera control unit 101 determines that the current charge level is equal to or higher than the maximum charge level at the time of main light emission failure (YES in S210), the camera control unit 101 advances the process to S211. On the other hand, if the camera control unit 101 determines that the current charge level is less than the maximum charge level at the time of main light emission failure (NO in S210), the camera control unit 101 advances the process to S221.

In S211, the camera control unit 101 causes the strobe control unit 301 to execute pre-flash control. Note that details of the pre-emission control will be described later. In S212, the camera control unit 101 acquires strobe information at the time of pre-flash and after the pre-flash from the strobe control unit 301. This information includes a pre-emission amount threshold flag. The strobe control unit 301 sets a pre-emission amount threshold flag (sets the pre-emission amount threshold flag to '1') when the pre-emission amount is equal to or greater than a predetermined pre-emission amount threshold. Conversely, if the pre-flash amount is less than the pre-flash amount threshold, the strobe control unit 301 does not set the pre-flash amount threshold flag (sets the pre-flash amount threshold flag to '0').

In S213, the camera control unit 101 determines whether the pre-light emission threshold flag is set (1) or not (0). If the camera control unit 101 determines that the pre-flash amount threshold flag is set (1) (YES in S213), the camera control unit 101 advances the process to S214, and determines that the pre-flash amount threshold flag is not set (0). If so (NO in S213), the process advances to S221.

In S214, the camera control unit 101 calculates the strobe light emission amount (main light emission amount) during main imaging based on the strobe information acquired in S212. In S215, the camera control unit 101 instructs the strobe control unit 301 to perform main light emission control, and performs an exposure operation (main imaging) in which driving of the image sensor 102, shutter 104, etc. is controlled.

In S216, the camera control unit 101 acquires strobe information during and after main light emission from the strobe control unit 301. This strobe information includes a main light emission threshold flag and a charge level at the time of main light emission (before and after main light emission). Note that the strobe control unit 301 sets a main light emission amount threshold flag (sets the main light emission amount threshold flag to '1') when the main light emission amount is equal to or greater than a predetermined main light emission amount threshold. Conversely, if the main light emission amount is less than the main light emission amount threshold, the strobe control unit 301 does not set the main light emission amount threshold flag (sets the main light emission amount threshold flag to '0').

In S217, the camera control unit 101 determines whether the preliminary light emission amount threshold flag obtained in S212 is set (1) and the main light emission amount threshold flag obtained in S216 is not set (0). When the camera control unit 101 determines that the pre-light emission amount threshold flag (1) and the main light emission amount threshold flag (0) are set (YES in S217), the process proceeds to S218. On the other hand, when the camera control unit 101 determines that the pre-light emission amount threshold flag (0) or the main light emission amount threshold flag (1) is set (NO in S217), this process ends.

In S218, the camera control unit 101 increments the number of times the pre-flash was possible but the main light-emission was not possible as the "main light-flash NG count". In S219, the camera control unit 101 determines whether the charge level at the time of main light emission acquired in S216 is equal to or higher than the maximum charge level at the time of main light emission NG, which will be described later. If the camera control unit 101 determines that the charge level at the time of main light emission is equal to or higher than the maximum charge level at the time of main light emission NG (YES in S219), the camera control unit 101 advances the process to S220. On the other hand, if the camera control unit 101 determines that the charge level at the time of main light emission is less than the maximum charge level at the time of main light emission NG (NO in S219), this process ends.

In S220, the camera control unit 101 sets a value obtained by adding a predetermined value α to the charge level at the time of main light emission obtained in S216 (here, the charge level below the main light emission amount threshold) as the maximum charge level at the time of main light emission NG. settings, and then terminate this process.

Note that if the maximum charge level at the time of main flash failure is set to be the same as the charge level during the most recent main flash, even if the determination in S210 in the next imaging is YES and the light emission control is performed, the desired main flash will not be activated in S215. There is a high possibility that the amount of light emitted will not be obtained. Therefore, by controlling the light emission when the charge level reaches the charge level obtained by adding a predetermined value α to the charge level at the time of main light emission in the next S210, it is possible to reduce the possibility that imaging is performed due to insufficient main light emission amount. becomes possible.

On the other hand, the higher the maximum charge level when the main light emission fails, the fewer times the main light emission can be performed (the number of times the process proceeds to S215), so the processes of S209 and S210 are provided. For example, if the "predetermined number of times" used in the determination in S209 is 5 times, the charge level is not limited up to 4 times, so even if the light emission amount is smaller than the main flash threshold, the main flash is activated in S215. Image acquisition becomes possible.

In S221, which is the next process when the determinations in S208, S210, and S213 are "NO", the camera control unit 101 controls the driving of the image sensor 102, the shutter 104, etc., and performs exposure without strobe light emission. The operation (imaging operation) is executed, and then this processing is ended. Note that when moving to the next imaging in continuous flash photography, the process returns from "End" to S206 in the flowchart of FIG.

Next, a description will be given of the control of the operation of the strobe device 300 by the strobe control unit 301, which is instructed to perform pre-emission control by the camera control unit 101 in S211. FIG. 3 is a flowchart illustrating pre-flash control in the strobe device 300. Each process (step) indicated by an S number in FIG. 3 is realized by the strobe control unit 301 executing a predetermined program to collectively control the operation of each part of the strobe device 300.

When the strobe control unit 301 receives a pre-flash control command from the camera control unit 101 via the strobe contact group 109, it starts pre-flash control. In S300, the strobe control unit 301 sets parameters for pre-flash based on the pre-flash control information received from the camera control unit 101. In S301, the strobe control unit 301 controls the light emitting unit 302 based on the parameters set in S300 to perform pre-light emission. At this time, the strobe control unit 301 uses information obtained from the photocurrent detection unit 306 to perform control so that an appropriate amount of light is emitted (irradiated onto the subject). Note that the camera control unit 101 and the strobe control unit 301 synchronize the strobe light emission and the exposure timing of the image sensor 102 by performing timing control via the strobe contact group 109.

In S302, the strobe control unit 301 acquires information on the amount of light actually emitted during pre-emission. The light emission amount information may be a voltage obtained by integrating the photocurrent obtained at the time of light emission obtained from the photocurrent detection unit 306, or a voltage calculated from the voltage difference (energy difference) of the charging unit 305 before and after light emission.

In S303, the strobe control unit 301 determines whether the pre-flash amount obtained in S302 is equal to or greater than a predetermined pre-flash amount threshold. The pre-light emission amount threshold may be a fixed value or may be variable depending on the light emission parameters. If the strobe control unit 301 determines that the pre-flash amount is equal to or greater than the pre-flash amount threshold (YES in S303), the strobe control unit 301 advances the process to S304, and if it determines that the pre-flash amount is less than the pre-flash amount threshold (S303). (NO), the process advances to S305.

In S304, the strobe control unit 301 sets the pre-emission amount threshold flag to '1', and then ends this process. On the other hand, in S305, the strobe control unit 301 sets the pre-emission amount threshold flag to '0', and then ends this process.

Next, the control of the operation of the strobe device 300 by the strobe control unit 301, which is instructed to perform main light emission control by the camera control unit 101 in S215, will be explained. FIG. 4 is a flowchart illustrating main light emission control in the strobe device 300. Each process (step) indicated by an S number in FIG. 4 is realized by the strobe control unit 301 executing a predetermined program to comprehensively control the operation of each part of the strobe device 300.

When the strobe control unit 301 receives a main light emission control command from the camera control unit 101 via the strobe contact group 109, it starts main light emission control. In S400, the strobe control unit 301 sets parameters for main light emission based on the pre-flash information held by itself and the main light emission control information received from the camera control unit 101. In S401, the strobe control unit 301 acquires the voltage value charged in the light emission capacitor and sets the charge level for main light emission.

In S402, the strobe control unit 301 controls the light emitting unit 302 to perform main light emission based on the parameters set in S400. At that time, the information obtained from the photocurrent detection unit 306 is used to control the emission of an appropriate amount of light. Note that the camera control unit 101 and the strobe control unit 301 synchronize the strobe light emission and the exposure timing of the image sensor 102 by performing timing control via the strobe contact group 109.

In S403, the strobe control unit 301 obtains information on the amount of light actually emitted during main light emission. The light emission amount information may be a voltage obtained by integrating the photocurrent obtained at the time of light emission obtained from the photocurrent detection unit 306, or a voltage calculated from the voltage difference (energy difference) of the charging unit 305 before and after light emission.

In S404, the strobe control unit 301 determines whether the main light emission amount obtained in S403 is equal to or greater than a predetermined main light emission amount threshold. Note that the main light emission amount threshold may be a fixed value or may be variable depending on the light emission parameters. If the strobe control unit 301 determines that the main light emission amount is equal to or greater than the main light emission amount threshold (YES in S404), the strobe control unit 301 advances the process to S405, and if it determines that the main light emission amount is less than the main light emission amount threshold (S404). (NO), the process advances to S406.

In S405, the strobe control unit 301 sets the main light emission amount threshold flag to '1', and then ends this process. On the other hand, in S406, the strobe control unit 301 sets the main light emission amount threshold flag to '0', and then ends this process.

In the light emission control according to the flowchart of FIG. 2, the number of main light emission failures and the maximum charge level at the time of main light emission failure need to be reset when the strobe device 300 is attached to and detached from the camera body 100. Next, a description will be given of the process that the camera control unit 101 executes when there is a change in the attachment state of the strobe device 300 to the camera body 100.

FIG. 5 is a flowchart of the control performed by the camera control unit 101 when the attachment state of the strobe device 300 to the camera body 100 changes. Each process (step) indicated by an S number in the flowchart of FIG. 5 is realized by the camera control unit 101 executing a predetermined program to comprehensively control the operation of each part of the camera body 100.

In S500, the camera control unit 101 determines via the strobe contact group 109 whether there is a change in the mounting state of the camera body 100 and the strobe device 300 (from non-mounted to mounted, or from mounted to non-mounted). judge. If the camera control unit 101 determines that there is a change in the wearing state (YES in S500), the process proceeds to S501, and if it determines that there is no change in the wearing state (NO in S500), it ends this process.

Note that the camera control unit 101 switches from the normal operation mode to the power saving mode when a power switch (not shown), which is one of the camera operation units 105, is turned off or when a predetermined period of no operation time has elapsed. Switch. At that time, if the system configuration is such that the camera control unit 101 cannot detect a change in the wearing state, the camera control unit 101 proceeds to step S501 regardless of whether there is a change in the wearing state. Proceed. Further, when a setting reset switch (not shown), which is one of the camera operation sections 105, is operated, the camera control section 101 advances the process to S501 regardless of the change in the wearing state.

In S501, the camera control unit 101 initializes the main light emission failure count (sets it to '0'). Then, in S502, the camera control unit 101 initializes (sets to '0') the maximum charge level when the main light emission fails, and thereby ends this process.

As explained above, in strobe photography according to the first embodiment, when automatic flash control is performed in a mode that allows flash emission even if the charge level for strobe light emission is less than a predetermined charge level, the number of main flash failures is reduced. Count and remember. Then, when the number of main light emission failures exceeds a predetermined number of times, it is switched whether or not to execute light emission control according to the charge level at the time of imaging (when SW2 signal is on). Thereby, it is possible to reduce the possibility that even if pre-light emission is performed, main light-emission is not performed, and thus an image is not properly exposed.

<Second embodiment>
In the first embodiment, the number of times the main light emission fails and the maximum charge level at the time of the main light emission failure are held on the camera body 100 side. On the other hand, in the second embodiment, the strobe device 300 maintains the number of times the main light emission fails and the maximum charge level when the main light emission fails.

FIG. 6 is a flowchart illustrating control in strobe photography by the imaging apparatus 1000 according to the second embodiment. Each process (step) indicated by an S number in the flowchart of FIG. 6 is realized by the camera control unit 101 executing a predetermined program to collectively control the operation of each unit of the imaging apparatus 1000. Note that in the second embodiment as well, it is assumed that the automatic light control mode is set. Further, the flowchart in FIG. 6 is based on the premise of continuous flash photography in which strobe photography is performed continuously, and the end of the flowchart represents the end of capturing one image.

The processes in S600 to S608 and S613 are the same as the processes in S200 to S208 and S213 in the flowchart of FIG. 2 in the first embodiment, so their explanation will be omitted. In S609, the camera control unit 101 causes the strobe control unit 301 to execute pre-flash control.

Here, the control of the operation of the strobe device 300 by the strobe control section 301, which is instructed to perform pre-emission control by the camera control section 101, will be explained. FIG. 7 is a flowchart illustrating pre-light emission control in the strobe device 300. Each process (step) indicated by an S number in FIG. 7 is realized by the strobe control unit 301 executing a predetermined program to collectively control the operation of each part of the strobe device 300.

When the strobe control unit 301 receives a pre-flash control command from the camera control unit 101 via the strobe contact group 109, it starts pre-flash control. In S700, the strobe control unit 301 determines whether the number of main light emission failures is equal to or greater than a predetermined number of times. The definition of the main light emission failure count is as explained in the first embodiment. If the strobe control unit 301 determines that the number of main flash failures is equal to or greater than the predetermined number of times (YES in S700), the strobe control unit 301 advances the process to S701, and if it determines that the number of main flash failures is less than the predetermined number of times (NO in S700). ), the process advances to S702.

In S701, the strobe control unit 301 obtains the voltage value charged in the light emission capacitor as the current charge level, and determines whether the current charge level is equal to or higher than the maximum charge level at the time of main light emission failure. If the strobe control unit 301 determines that the current charge level is equal to or higher than the maximum charge level at the time of main light emission failure (YES in S701), the flash control unit 301 advances the process to S702. On the other hand, if the strobe control unit 301 determines that the current charge level is less than the maximum charge level at the time of main light emission failure (NO in S701), the process proceeds to S707. The processing from S702 to S707 is the same as the processing from S300 to S305 in the flowchart of FIG. 3, so the explanation will be omitted.

Returning to the explanation of the flowchart in FIG. 6. In S610, the camera control unit 101 acquires strobe information at the time of pre-flash and after the pre-flash from the strobe control unit 301. In S611, the camera control unit 101 calculates the strobe light emission amount (main light emission amount) during main imaging based on the strobe information acquired in S610. In S612, the camera control unit 101 instructs the strobe control unit 301 to perform main light emission control, performs an exposure operation (main imaging) by controlling the driving of the image sensor 102, shutter 104, etc., and then ends the main processing. .

Here, the control of the operation of the strobe device 300 by the strobe control section 301, which is instructed to perform main light emission control by the camera control section 101, will be explained. FIG. 8 is a flowchart illustrating main light emission control in the strobe device 300. Each process (step) indicated by an S number in FIG. 8 is realized by the strobe control unit 301 executing a predetermined program to collectively control the operation of each part of the strobe device 300.

When the strobe control unit 301 receives a main light emission control command from the camera control unit 101 via the strobe contact group 109, it starts main light emission control. In S800, the strobe control unit 301 determines whether the pre-flash amount threshold flag acquired in the pre-flash operation is set (1) or not (0). If the strobe control unit 301 determines that the pre-flash amount threshold flag is set (1) (YES in S800), the process proceeds to SS801, and if it determines that the pre-flash amount threshold flag is not set (0). (NO in S800), this process is ended. The processing from S801 to S805 is the same as the processing from S400 to S404 in the flowchart of FIG. 4, so the description thereof will be omitted.

If the strobe control unit 301 determines in S805 that the main light emission amount is greater than or equal to the main light emission amount threshold (YES in S805), it terminates this process and determines that the main light emission amount is less than the main light emission amount threshold. If so (NO in S805), the process advances to S806. In S806, the strobe control unit 301 increments the main light emission failure count. In S807, the strobe control unit 301 determines whether the charge level during main light emission set in S801 is equal to or higher than the maximum charge level at the time of main light emission failure. If the strobe control unit 301 determines that the charge level at the time of main light emission is equal to or higher than the maximum charge level at the time of main light emission NG (YES in S807), the process advances to S808. On the other hand, if the strobe control unit 301 determines that the charge level at the time of main light emission is less than the maximum charge level at the time of main light emission NG (NO in S807), this process ends.

In S808, the strobe control unit 301 adds a predetermined value α to the charge level at the time of main light emission acquired in S801 (here, the charge level at which the main light emission amount is less than the main light emission amount threshold), and sets the value to the maximum value at the time of main light emission failure. Set as the charge level, and then end this process.

Next, a process executed by the strobe control unit 301 when there is a change in the attachment state of the strobe device 300 to the camera body 100 will be described. FIG. 9 is a flowchart of control performed by the strobe control unit 301 when the mounting state of the strobe device 300 on the camera body 100 changes. Each process (step) indicated by an S number in the flowchart of FIG. 9 is realized by the strobe control unit 301 executing a predetermined program to collectively control the operation of each part of the strobe device 300.

In S900, the strobe control unit 301 determines via the strobe contact group 109 whether there has been a change in the attachment state of the camera body 100 and the strobe device 300 (from non-attached to attached, or from attached to non-attached). judge. If the strobe control unit 301 determines that there is a change in the wearing state (YES in S900), the process proceeds to S901, and if it determines that there is no change in the wearing state (NO in S900), it ends the process.

Note that the strobe control unit 301 switches from the normal operation mode to the power saving mode when a power switch (not shown), which is one of the strobe operation units 303, is turned off or when a predetermined period of no operation has elapsed. Switch. At this time, if the system configuration is such that the strobe control unit 301 cannot detect a change in the wearing state, the strobe control unit 301 proceeds to step S901 regardless of whether there is a change in the wearing state. Proceed. Further, if a setting reset switch (not shown), which is one of the strobe operation units 303, is operated, the strobe control unit 301 advances the process to S901 regardless of the change in the wearing state.

In S901, the strobe control unit 301 initializes the main light emission NG count (clears the main light emission NG count (sets to zero)). Then, in S902, the strobe control unit 301 initializes (sets to zero) the maximum charge level when the main light emission fails, and thereby ends this process.

As described above, in the second embodiment of the present invention, the same light emission control as in the first embodiment is performed, so even if pre-flash is performed, main flash is not performed, resulting in imaging that does not result in proper exposure. can be reduced.

Although the present invention has been described above in detail based on its preferred embodiments, the present invention is not limited to these specific embodiments, and the present invention may take various forms without departing from the gist of the present invention. included. Further, each of the embodiments described above is merely one embodiment of the present invention, and each embodiment can be combined as appropriate.

For example, in the embodiments described above, the imaging device is configured such that the lens and the illumination device are detachable from the imaging device main body. However, the present invention is not limited to such a configuration; for example, even if the lens is configured integrally with the imaging device main body, and the illumination device is built in the imaging device main body, the present invention can be applied. Application is possible. In that case, the camera control section 101 may have the functions of the lens control section 201 and the flash control section 301. Further, the camera operation section 105 can have the function of the strobe operation section 303.

In the above-described configuration in which the lighting device is detachable from the imaging device main body, the light emission control is reset in response to changes in the attachment/detachment state of the imaging device main body and the lighting device. On the other hand, in the case of a configuration in which an illumination device is built into the imaging device main body, the light emission control can be reset in response to a change in the settings of the imaging conditions in the imaging device.

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

100 Camera body (imaging device body)
101 Camera control section 102 Imaging device 105 Camera operation section 200 Lens 202 Imaging lens 300 Illumination device 301 Strobe control section 302 Light emitting section 305 Charging section 306 Photocurrent detection section 1000 Imaging device

Claims (10)

a light emitting unit that irradiates light to a subject when imaging by the imaging means;
a charging unit that supplies energy for light emission to the light emitting unit;
a light control unit that causes the light emitting unit to emit light preliminarily to take an image, and determines a main light emission amount when causing the light emitting unit to emit light during main imaging based on the image acquired by the image capturing unit;
Setting means for setting a light emission mode in which the light emitting section emits light even when the charging section is at a charging level at which it is not possible to obtain the main light emission amount determined by the light control means during main imaging;
When the light emission mode is set, after the pre-flash can be performed and the number of times the main light emission amount determined by the light control means during main imaging has not been obtained reaches a predetermined number of times, An imaging device characterized by comprising: a control unit that executes light emission control to determine a main light emission amount by the light control unit and perform main light emission only when the current charging unit is at a predetermined charge level or higher. Device. The imaging device according to claim 1, wherein the control unit executes the light emission control regardless of the charging level of the charging unit until the number of times reaches the predetermined number of times. The control means is characterized in that, after the number of times reaches the predetermined number of times, if the current charging unit does not reach a predetermined charge level, the control means performs control such that imaging is performed without performing the light emission control. The imaging device according to claim 1 or 2. comprising an operating means that allows changing the imaging conditions of the imaging device from the outside;
2. The control means executes the light emission control regardless of the charging level of the charging unit when a change in the setting of the imaging condition is received via the operation means. 4. The imaging device according to any one of 3 to 3. An imaging device main body,
a lighting device that is detachable from the imaging device main body;
The lighting device includes at least the light emitting section, the charging section, and the setting means,
The imaging device according to any one of claims 1 to 4, wherein the imaging device main body includes at least the light control means and the control means. The imaging device main body includes:
storage means for storing the number of times;
Detecting means for detecting a change in the mounting state of the imaging device main body and the lighting device,
The control means initializes the number of times stored in the storage means when the detection means detects that there is a change in the mounting state of the imaging device main body and the illumination device. The imaging device according to claim 5. The lighting device includes:
storage means for storing the number of times;
detection means for detecting a change in the mounting state of the imaging device main body and the illumination device;
The apparatus further comprises an initializing means for initializing the number of times stored in the storage means when the detection means detects that there is a change in the mounting state of the imaging device main body and the illumination device. The imaging device according to claim 5. means for determining a voltage value by converting the light emitted from the light emitting part into a current and integrating it;
The imaging apparatus according to any one of claims 1 to 7, further comprising a determination unit that determines whether or not each of the pre-light emission and the main light emission is executed based on the voltage value. means for determining a voltage difference before and after each of the pre-emission and the main emission in the charging section;
The imaging apparatus according to any one of claims 1 to 7, further comprising a determination unit that determines whether or not each of the pre-light emission and the main light emission is executed based on the voltage difference. A method for controlling an imaging device, the method comprising:
a setting step of setting a light emission mode that causes the light emitting unit to emit light even if a charging unit that supplies energy to cause the light emitting unit to emit light during main imaging is at a charging level that does not allow the main light emission amount to be obtained;
a dimming step of causing the light emitting unit to pre-emit light to take an image and determining a main light emission amount by the light emitting unit when performing main imaging based on the image acquired by the imaging means;
When the light emission mode is set, after the pre-flash can be performed and the number of times the main light emission amount determined in the light adjustment step during main imaging has reached a predetermined number of times, A control method for an imaging device, comprising: a control step of determining a main light emission amount by the light adjustment step and performing main light emission only when the current charging unit is at a predetermined charge level or higher.

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