JP6016377B2 - Illumination device and imaging system - Google Patents

Description

  The present invention relates to an illumination device and an imaging system, and more particularly to control when an optical accessory that changes the color characteristics of transmitted light is attached in front of a light emitting unit of the illumination device.

  Generally, in an illumination device such as a strobe device used in a camera, a discharge tube such as a xenon tube is used as the light source. The color temperature of irradiation light (strobe light) in a strobe device using a xenon tube is set near sunlight (6000 K). For this reason, when shooting is performed using a strobe device in an environment having a color temperature different from the color temperature, an unnatural color captured image may be obtained.

  Therefore, Patent Document 1 proposes a technique for changing the color temperature of the irradiation light of the strobe device by attaching a filter holder having an optical accessory such as a color filter attached in front of the light emitting portion of the strobe device. In patent document 1, identification information for identifying the type of color filter is added to the color filter side, and the color filter attached to the filter holder is read by reading the identification information of the color filter with a reading unit provided on the strobe device side. Identify the type. Then, the strobe device determines the color temperature of the irradiation light from the identified type of the color filter, and displays the color temperature information on the display unit or transmits the color temperature information to the attached camera.

JP 2009-20298 A

  By the way, when an optical accessory that changes the color characteristics of transmitted light is attached in front of the light emitting unit, not only the color temperature of the irradiated light is converted but also a phenomenon that the irradiated light is attenuated occurs. Then, the imaging apparatus equipped with the strobe performs preliminary light emission before the main light emission of the strobe, and acquires information (subject information) about the subject used for the main light emission amount calculation.

  For this reason, when the optical accessory is attached to the strobe, if the imaging device does not acquire attenuation information indicating the attenuation of the amount of irradiation light due to the attachment of the optical accessory, the main light emission amount calculation is performed according to erroneous subject information. As a result, an appropriate main light emission amount may not be obtained.

  Accordingly, an object of the present invention is to make it possible to obtain an appropriate amount of light emission even when an optical accessory that changes the color characteristics of transmitted light is attached in front of a light emitting unit of a lighting device.

In order to achieve the above object, an illumination device according to the present invention is an illumination device in which an optical accessory that changes a color characteristic of transmitted light can be attached in front of a light emitting unit and is detachable from an imaging device. An acquisition unit that acquires information about the characteristics of the optical accessory attached in front of the unit, and a preliminary light emission amount that is a light emission amount at the time of preliminary light emission based on the information about the characteristics of the optical accessory acquired by the acquisition unit A calculation unit that calculates information indicating a corrected preliminary light emission amount corrected according to the amount of light dimmed by the optical accessory, and an imaging device that is equipped with information indicating the corrected preliminary light emission amount calculated by the calculation unit Transmitting means for transmitting to the apparatus.

An imaging system according to the present invention is an imaging system including an illuminating device to which an optical accessory that changes a color characteristic of transmitted light can be attached in front of a light emitting unit, and the imaging device, wherein the illuminating device includes the light emitting unit. Based on the information on the characteristics of the optical accessory acquired by the acquisition means, the acquisition means for acquiring the information on the characteristics of the optical accessory attached in front of On the other hand, calculation means for calculating information indicating the corrected preliminary light emission amount corrected according to the amount of light dimmed by the optical accessory, and transmission means for transmitting information indicating the corrected preliminary light emission amount calculated by the calculation means; The imaging device includes photometry means, receiving means for receiving information indicating the corrected preliminary light emission amount, and the preliminary emission by the illumination device. A determination unit configured perform preliminary light emission, based on the information representing the corrected preliminary light emission amount received by the receiving means photometric value obtained by the photometry means, for determining the main light emission amount of the illumination device in an amount, It is characterized by having.

  According to the present invention, an appropriate main light emission amount can be obtained even when an optical accessory that changes the color characteristics of transmitted light is attached in front of the light emitting unit of the lighting device.

It is sectional drawing which shows roughly an example of the imaging device with which the illuminating device by the 1st Embodiment of this invention was mounted | worn. It is a figure which shows an example of the structure of the filter holder containing a color filter at the time of seeing the light emission part shown in FIG. 1 from the front, and a filter detection part. It is a flowchart for demonstrating the light emission operation | movement of the illuminating device shown in FIG. 4 is a flowchart for explaining calculation of a corrected preliminary light emission amount shown in FIG. 3. It is a figure which shows an example of the chromaticity information at the time of using the most common orange color filter as a color filter shown in FIG. It is a figure which shows an example of the light emission reduction light quantity table memorize | stored in the flash microcomputer shown in FIG. It is a flowchart for demonstrating the process by the camera microcomputer shown in FIG. It is a flowchart for demonstrating the process of the camera microcomputer in release operation | movement in case the illuminating device is mounted | worn. It is a flowchart for demonstrating calculation of the correction | amendment preliminary light emission amount in the imaging device by the 2nd Embodiment of this invention. It is a figure which shows the spectral characteristics of a discharge tube, a light source, and a color sensor as shown to the discharge tube shown in FIG.

  Hereinafter, an example of a lighting device according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing an example of an imaging apparatus which is an imaging system equipped with the illumination apparatus according to the first embodiment of the present invention.

  The illustrated imaging apparatus (hereinafter simply referred to as a camera) includes a camera body (imaging apparatus body) 100, a lens unit (imaging lens unit) 200, and an illumination device (hereinafter simply referred to as a strobe) 300 that can be attached to and detached from the camera body 100. Have.

  The camera body 100 includes a microcomputer (camera microcomputer: CCPU) 101 that controls each part of the camera. The camera microcomputer 101 is, for example, a microcomputer built-in one on which a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, and the like are mounted. It is a chip IC circuit.

  Furthermore, the camera body 100 includes an image sensor 102 such as a CCD or CMOS sensor, and the image sensor 102 includes an infrared cut filter, a low-pass filter, and the like. An optical image (subject image) from the lens unit 200 is formed on the image sensor 102.

  The shutter 103 shields the image sensor 102 when not photographing, and is opened when the image is photographed to guide the optical image to the image sensor 102. The main mirror (half mirror) 104 reflects light incident from the lens unit 200 and forms an image on the focus plate 105 when not photographing. The optical image formed on the focus plate 105 can be confirmed with an optical viewfinder (not shown).

  The photometric circuit (AE) 106 has a photometric sensor, and the photometric sensor divides the photographing range into a plurality of areas and performs photometry in each divided area. The photometric sensor receives a subject image formed on the focusing plate 105 via the pentaprism 114. The focus detection circuit (AF) 107 has a distance measuring sensor. The distance measuring sensor includes a plurality of distance measuring points, and the distance to the subject is measured by the distance measuring sensor.

  The gain switching circuit 108 is a circuit for switching a gain (amplification factor) when the output signal (analog signal) from the image sensor 102 is amplified. Under the control of the camera microcomputer 101, the gain switching circuit 108 performs gain switching based on shooting conditions, level setting based on charging voltage conditions, and a photographer's instruction.

  The A / D converter 109 converts an analog signal that is an output of the image sensor 102 into a digital signal. A timing generator (TG) 110 synchronizes the output timing of the image sensor 102 and the conversion timing of the A / D converter 109 under the control of the camera microcomputer 101.

  The digital signal processing circuit 111 receives a digital signal from the A / D converter 109 and performs image processing corresponding to the parameter on the digital signal to obtain image data. In FIG. 1, a memory and the like are omitted for recording image data.

  The camera body 100, the lens unit 200, and the strobe 300 are connected by an interface signal line SC. For example, using the interface signal line SC, the camera main body 100, the lens unit 200, and the flash unit mutually exchange data and transmit commands using the camera microcomputer 101 as a host. As a result, a light emission start signal is sent from the camera microcomputer 101 to the strobe 300. In addition, a communication clock is sent to the flash microcomputer 310, and communication is performed between the camera microcomputer 101 and the flash microcomputer 310.

  Also, data is transmitted from the lens microcomputer 201 to the camera microcomputer 101 via the interface signal line SC, and communication is performed between the camera microcomputer 101 and the lens microcomputer 201.

  The input unit 112 includes a release switch for starting a photographing operation. The display unit 113 displays the set mode and other shooting information. The display unit 113 includes, for example, a liquid crystal device and a light emitting element. As described above, the pentaprism 114 guides the subject image formed on the focus plate 105 to the photometric sensor and guides it to the optical viewfinder. The sub mirror 115 guides the optical image incident from the lens unit 200 and transmitted through the main mirror 104 to the distance measuring sensor of the focus detection circuit 107.

  The lens unit 200 includes a microcomputer (lens microcomputer: LPU) 201 that controls each part of the lens unit 200. The lens microcomputer 201 is, for example, a microcomputer built-in one on which a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, and the like are mounted. It is a chip IC circuit. Then, the lens microcomputer 201 performs various condition determinations described later.

  The lens unit 200 includes a lens group 202 composed of a plurality of lenses. The lens driving unit 203 drives the lens group 202 under the control of the lens microcomputer 201 to perform focus position alignment. The encoder 204 detects the position of the lens group 202 and outputs lens position information to the camera microcomputer 101. Then, the lens microcomputer 201 sends lens position information to the camera microcomputer 101. The camera microcomputer 101 can know the distance to the subject (subject distance) according to the lens position information.

  A diaphragm control circuit 206 controls the diaphragm 205 under the control of the lens microcomputer 201. The focal length of the lens group 202 may be a single focal point, or the focal length may be variable like a zoom lens.

  The strobe 300 is provided with a battery 301, and this battery 301 is used as a power supply (VBAT) of the strobe. The battery 301 is connected to a booster circuit 302 and a strobe microcomputer (FPU) 310. The booster circuit 302 is a circuit that boosts the voltage of the battery 301 to several hundred volts, and stores energy for light emission in the main capacitor 303. The booster circuit 302 is connected to the a terminal of the strobe microcomputer 310, and the strobe microcomputer 310 controls charging.

  The main capacitor 303 is a high-voltage capacitor for strobe light emission. The main capacitor 303 is charged to, for example, 330 V and is discharged during light emission. The voltage detection circuit 313 includes a resistor 304 and a resistor 305, and the voltage charged by the main capacitor 303 is divided by the resistors 304 and 305. The divided voltage is input to the i terminal of the stroboscopic microcomputer 310 and is supplied from the stroboscopic microcomputer 310 to the A / D conversion terminal.

  The trigger circuit 306 is connected to the b terminal of the strobe microcomputer 310, and a trigger signal pulse is given to the trigger circuit 306 from the strobe microcomputer 310 when light is emitted. The discharge tube 307 emits light by exciting the energy charged in the main capacitor 303 upon receiving a pulse voltage of several KV applied from the trigger circuit 306. The light emission control circuit 308 controls the start of light emission of the discharge tube 307 together with the trigger circuit 306, and further controls the stop of light emission.

  The integrating circuit 309 is for integrating the light receiving current of the photodiode (light receiving unit) 323. The input of the integration circuit 309 is connected to the f terminal of the flash microcomputer 310, and an integration start signal is given from the flash microcomputer 310 to the integration circuit 309. The output of the integration circuit 309 is input to the A / D converter terminal via the inverting input terminal of the comparator 312 and the e terminal of the strobe microcomputer 310.

  The strobe microcomputer 310 controls each part of the strobe 300. The strobe microcomputer 310 is, for example, a microcomputer built-in one on which a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, and the like are mounted. It is a chip IC circuit.

  The voltage detection circuit 313 is connected to both ends of the main capacitor 303 and detects the main capacitor voltage. A voltage detection signal from the voltage detection circuit 313 is sent from the flash microcomputer 310 to the camera microcomputer 101 via the interface signal line SC.

  The non-inverting input of the comparator 312 is connected to the D / A converter output terminal via the d terminal of the strobe microcomputer 310, and the output of the comparator 312 is connected to the input terminal of the AND gate 311. The other input of the AND gate 311 is connected to the light emission control terminal via the c terminal of the flash microcomputer 310, and the output of the AND gate 311 is input to the light emission control circuit 308.

  The strobe 300 is provided with a reflector 315 and an optical system 316 that has a panel or the like and determines an irradiation angle of the strobe 300. The output of the input unit (input interface) 320 is connected to the h terminal of the flash microcomputer 310. For example, a switch is installed on the side of the housing of the strobe 300, and information about the strobe (strobe information) can be input manually. The display unit 321 is connected to the g terminal of the flash microcomputer 310. The display unit 321 displays the state of the strobe 300.

  The photodiode 323 is used as a sensor that receives the amount of light emitted from the discharge tube (light emitting unit) 307, and receives light from the discharge tube 307 directly or through a glass fiber. Then, the output current of the photodiode 323 is integrated in the integration circuit 309.

  The discharge tube 307, the reflector 315, the optical system 316, the filter holder detection switch 322, the filter detection unit 324, and the like constitute the light emitting unit 350.

  FIG. 2 is a diagram illustrating an example of the structure of the filter holder 400 including the color filter 401 and the filter detection unit 324 when the light emitting unit 350 illustrated in FIG. 1 is viewed from the front.

  In FIG. 2, the filter holder 400 is placed on the optical system 316 of the light emitting unit 350 shown in FIG. A filter detection unit 324 is attached to the filter holder 400. The filter detection unit 324 includes a light source 402, a color sensor 403, and a reflection unit 404. The light source 402 is, for example, a white LED, and the color sensor 403 has, for example, a photodiode and a plurality of color filters 401 having different spectral characteristics. The reflection unit 404 reflects the detection light emitted from the light source 402 and enters the color sensor 403.

  When the filter holder 400 is attached to the light emitting unit 350, the filter holder detection switch 322 shown in FIG. 1 is turned on. When the filter holder detection switch 322 is turned on, a color filter identification sequence described later is started, and light emitted from the light source 402 is transmitted through the color filter 401. The color characteristics of the light transmitted through the color filter 401 change depending on the spectral characteristics of the color filter 401. Then, the light transmitted through the color filter 401 is reflected by the reflection unit 404 and irradiated to the color sensor 403 (that is, a photodiode).

  The strobe microcomputer 310 identifies the type of the color filter based on the spectral characteristics of the color filter, that is, the detection signal output from the color sensor 403 according to the transmitted light.

  FIG. 3 is a flowchart for explaining the light emission operation of the strobe 300 shown in FIG. The control related to the light emission operation shown in FIG.

  Now, when a power switch (not shown) is turned on and the camera microcomputer 101 of the camera body 100 becomes operable, the flash microcomputer 310 initializes a memory and a port (not shown) (step S101). Further, the flash microcomputer 310 reads the state of the switch in the input unit 320 and preset input information, and sets the flash shooting mode, the light emission amount, and the like. When the flash microcomputer 310 receives the flash information from the camera microcomputer 101 via the interface communication line SC, the flash microcomputer 310 receives the flash information. The strobe microcomputer 310 stores strobe information in a RAM (not shown).

  Subsequently, the flash microcomputer 310 detects a color filter. When the color filter is detected, the stroboscopic microcomputer 310 obtains a light reduction amount G of the stroboscopic light according to the type of the color filter. Then, the flash microcomputer 310 obtains a corrected preliminary light emission amount H in which the reduced light amount G is reflected in the preliminary light emission amount O (step S102).

  As described above, whether or not the filter holder is attached is determined by the filter holder detection switch 322. When the filter holder detection switch 322 is turned on, the flash microcomputer 310 performs the process of step S102.

  FIG. 4 is a flowchart for explaining the calculation of the corrected preliminary light emission amount shown in FIG.

  The flash microcomputer 310 detects external light (environment light) via the color sensor 403 in a state where the light source 402 is not emitted (step S201). The color sensor 403 outputs an output corresponding to so-called three primary colors. Now, when external light is received, the color sensor 403 outputs (rn, gn, bn) as the three primary color information that is the light reception result.

  Subsequently, the flash microcomputer 310 controls lighting of the light source 402 (step S202), and the color sensor 403 receives the light transmitted through the color filter 401. The color sensor 403 detects the transmitted light and outputs (rs, gs, bs) as the three primary color information that is the light reception result (step S203).

  The stroboscopic microcomputer 310 uses the three primary color information (rs, gs, bs) by using the three primary color information (rn, gn, bn), that is, the external light chromaticity information (environment light chromaticity information) and the external light brightness information as noise. External light correction for dividing the three primary color information (rn, gn, bn) is performed (step S204). The stroboscopic microcomputer 310 performs division shown in Expression (1) to obtain corrected three primary color information (rc, gc, bc), that is, corrected lightness information and corrected chromaticity information.

rc = rs−rn
gc = gs-gn (1)
bc = bs-bn
The stroboscopic microcomputer 310 obtains chromaticity information (Br, Cx, Cy) of transmitted light transmitted through the color filter 401 by the following equation (2) based on the corrected three primary color information (rc, gc, bc). (Step S205).

  Here, if the coefficients M11 to M33 are appropriately selected, the corrected three primary color information (rc, gc, bc) has a lightness value (lightness information) Br indicating the brightness of the transmitted light and a chromaticity of the transmitted light of 2 It can be converted into chromaticity values (chromaticity information: transmitted light chromaticity information) Cx and Cy represented by an axis (xy chromaticity diagram).

  FIG. 5 is a diagram showing an example of chromaticity information Cx and Cy when the most common orange-based color filter is used as the color filter 401 shown in FIG.

  In FIG. 5, when the chromaticity information in the transmitted light increases, the orange color becomes darker. As a result, the dimming amount G increases. In the example shown in FIG. 5, X11, X12, X21, X22, X31, and X32 are defined as the chromaticity information Cx, and Y11, Y12, Y21, Y22, Y31, and Y32 is defined. A range in which the chromaticity information Cx is X11 or more and X12 or less and the chromaticity information Cy is Y11 or more and Y12 or less is defined as the first range.

  Similarly, a range in which chromaticity information Cx is X21 or more and X22 or less and chromaticity information Cy is Y21 or more and Y22 or less is defined as the second range. Further, a range in which the chromaticity information Cx is X31 or more and X32 or less and the chromaticity information Cy is Y31 or more and Y32 or less is defined as the third range.

  FIG. 6 is an example of a light emission reduction table that is stored in advance in the strobe microcomputer 310 shown in FIG. 1 and is information that associates information about the color characteristics of light transmitted through the color filter with information about the transmission characteristics of the color filter. FIG.

  In FIG. 6, chromaticity information Cx and Cy and emission reduction amount G are set in the emission reduction table. In the chromaticity information Cx and Cy, the above first to third ranges are set, and other Cx and Cy are set. Then, “−0.2F”, “−0.5F”, “−1.0F”, and “0” are set as the light emission reduction amount G corresponding to the chromaticity information Cx and Cy, respectively.

  Referring to FIG. 4 again, when the stroboscopic microcomputer 310 obtains the chromaticity information Cx and Cy as described above, the chromaticity information Cx and Cy is within the first range with reference to the light emission reduction table. It is determined whether or not (step S206).

  If the chromaticity information Cx and Cy are not within the first range (NO in step S206), the flash microcomputer 310 refers to the light emission reduction table, and the chromaticity information Cx and Cy is within the second range. It is determined whether or not there is (step S207). If the chromaticity information Cx and Cy are not within the second range (NO in step S207), the flash microcomputer 310 refers to the light emission reduction table, and the chromaticity information Cx and Cy is within the third range. It is determined whether or not there is (step S208).

  If the chromaticity information Cx and Cy are not within the third range (NO in step S208), the stroboscopic microcomputer 310 assumes that the chromaticity information Cx and Cy are outside the first to third ranges, and the emission light reduction table. Is determined as “0” (step S209). The stroboscopic microcomputer 310 obtains a corrected preliminary light emission amount H by the following equation (3) based on the light emission reduction amount G and the preliminary light emission amount O (step S210). Then, the flash microcomputer 310 ends the corrected preliminary light emission amount calculation process, and proceeds to the process of step S103 shown in FIG.

Corrected preliminary emission amount H = preliminary emission amount O × 2 ^{emission reduction amount G} (3)
Note that the preliminary light emission amount information indicating the preliminary light emission amount O represents the preliminary light emission amount when the color filter is not attached, and is stored in advance in the ROM or the EEPROM of the flash microcomputer 310.

  In step S206, when the chromaticity information Cx and Cy are within the first range (YES in step S206), the stroboscopic microcomputer 310 determines the light emission reduction amount G to be “−0.2F” from the light emission reduction amount table (step S206). Step S211) Then, the flash microcomputer 310 proceeds to the process of Step S210.

  In step S207, when the chromaticity information Cx and Cy are within the second range (YES in step S207), the flash microcomputer 310 determines the light emission reduction amount G to be “−0.5F” from the light emission reduction amount table. Then, the flash microcomputer 310 proceeds to the process of step S210. Similarly, if the chromaticity information Cx and Cy are within the third range in step S208 (YES in step S208), the flash The microcomputer 310 determines the light emission reduction amount G to be “−1.0F” from the light emission reduction amount table (step S213). Then, the flash microcomputer 310 proceeds to the process of step S210.

  In the flowchart shown in FIG. 4, the orange filter is described as an example of the color filter, but a light emission reduction amount table may be provided for each type of color filter. If the type of the color filter is identified, the light emission reduction amount G in various color filters can be obtained.

  Referring again to FIG. 3, after obtaining the corrected preliminary light emission amount H as described above, the flash microcomputer 310 starts the operation of the booster circuit 302 and prepares for light emission in S103 (step S103). Then, the flash microcomputer 310 receives camera information such as lens focal length information and light emission mode information from the camera microcomputer 101 via the interface signal line SC (step S104). Subsequently, the flash microcomputer 310 displays the flash information stored in the built-in memory on the display unit 321 (step S105). The strobe information includes information related to the corrected preliminary light emission amount H, which is information related to the transmission characteristics of the mounted color filter.

  Next, the flash microcomputer 310 outputs flash information to the camera microcomputer 101 via the interface signal line SC (step S106). The camera microcomputer 101 calculates the main light emission amount (light emission amount calculation value) according to the corrected preliminary light emission amount H included in the strobe information. Then, the camera microcomputer 101 gives a light emission amount calculation value to the strobe microcomputer 310, and the light emission amount calculation value is converted into a D / A converter value in the strobe microcomputer 310.

  Subsequently, the stroboscopic microcomputer 310 determines whether or not the voltage boosted by the booster circuit 302 has reached a voltage level necessary for light emission of the discharge tube 307 (whether charging is complete) (step S107). If the voltage boosted by booster circuit 302 has not reached the voltage level necessary for light emission of discharge tube 307 (NO in step S107), strobe microcomputer 310 indicates that the strobe light is not ready for light emission due to the incomplete charging signal. Inform the microcomputer 101. Then, the flash microcomputer 310 sends a charge signal to the booster circuit 302 for further charging (step S108), and returns to the process of step S103.

  When the voltage boosted by booster circuit 302 reaches a voltage level necessary for light emission of discharge tube 307 (YES in step S107), strobe microcomputer 310 informs camera microcomputer 101 that the strobe is ready for light emission by the charge completion signal. Notify (step S109). Then, the flash microcomputer 310 determines whether or not a light emission start signal (light emission trigger) has been transmitted from the camera microcomputer 101 (step S110).

  If the light emission trigger has not been transmitted (NO in step S110), the flash microcomputer 310 returns to the process of step S103. On the other hand, when the light emission trigger is transmitted (YES in step S110), the flash microcomputer 310 outputs a light emission start signal (high (Hi) level) from the light emission control terminal to the c terminal.

  As described above, the non-inverting input of the comparator 312 is connected to the D / A converter output terminal (d terminal) of the strobe microcomputer 310. Since the D / A converter value described above is output to the d terminal of the strobe microcomputer 310 and the output of the integrating circuit 309 is almost zero, the output of the comparator 312 becomes Hi level. As a result, the output of the AND gate 311 becomes Hi level, and a light emission trigger signal is given from the AND gate 311 to the light emission control circuit 308. As a result, the light emission control circuit 308 causes the discharge tube 307 to emit light. That is, the light emission control circuit 308 starts light emission of the strobe (step S111).

  When the strobe light emission starts, light from the discharge tube 307 is received by the photodiode 323 directly or via a glass fiber (not shown). The integration circuit 309 integrates the received light current, which is the output of the photodiode 323, and provides the output (integrated value) to the inverting input terminal of the comparator 312 and the A / D converter terminal of the strobe microcomputer 310.

  The stroboscopic microcomputer 310 compares the total received light amount obtained by A / D converting the integrated value with the D / A converter value, and determines whether or not to stop the light emission (step S112). If the total amount of received light is less than the D / A converter value (NO in step S112), strobe microcomputer 310 determines to continue light emission and waits. On the other hand, when the total amount of received light reaches the D / A converter value (YES in step S112), strobe microcomputer 310 determines that light emission is stopped.

  In this case, since the D / A converter value corresponding to the light amount determined according to the light emission amount calculation value is given from the d terminal to the non-inverting terminal of the comparator 312, the output of the comparator 312 is low (Lo) level. Become. Therefore, the output of the AND gate 311 becomes Lo level. That is, a light emission stop signal is given from the AND gate 311 to the light emission control circuit 308, and the light emission control circuit 308 stops light emission of the discharge tube 307 (step S113: light emission completion).

  When the flash microcomputer 310 determines to stop the light emission, it stops outputting the light emission start signal. Thereafter, the flash microcomputer 310 returns to the process of step S103.

  FIG. 7 is a flowchart for explaining processing by the camera microcomputer 101 shown in FIG.

  Now, when a power switch (not shown) is turned on, the camera microcomputer 101 becomes operable. When the camera microcomputer 101 becomes operable, the camera microcomputer 101 initializes the built-in memory port (step S301), and reads the switch state input from the input unit 112 and preset input information. Then, the shooting mode is set such as a shutter speed determination method and an aperture determination method.

  Subsequently, the camera microcomputer 101 determines whether or not a shutter button (not shown) is half-pressed (here, whether or not SW1 is on) (step S302). If SW1 is OFF (OFF in step S302), camera microcomputer 101 stands by.

  If SW1 is on (ON in step S302), the camera microcomputer 101 communicates with the lens microcomputer 201 of the lens unit 200 via the interface signal line SC. Then, the focal length information regarding the lens unit 200 and optical information necessary for distance measurement and photometry (hereinafter collectively referred to as lens information) are acquired (step S303).

  Subsequently, the camera microcomputer 101 checks whether or not the strobe 300 is attached to the camera body 100 (step S304). When the strobe 300 is attached to the camera body 100 (YES in step S304), the camera microcomputer 101 sends focal length information to the strobe microcomputer 310 via the interface signal line SC (step S305).

  As a result, the flash microcomputer 310 drives and controls a motor drive circuit (not shown) based on the focal length information, and controls the irradiation angle of the flash according to the detection result by the encoder (not shown). In addition, the camera microcomputer 101 sends an instruction to output information on the flash stored in the built-in memory to the flash microcomputer 310. The strobe microcomputer 310 outputs strobe information to the camera microcomputer 101. The strobe information data includes information indicating the current light emission mode, information related to charging of the main capacitor, and the like.

  Subsequently, the camera microcomputer 101 determines whether or not the shooting mode is a mode (AF mode) in which an automatic focus detection operation is performed (step S306). If the strobe 300 is not attached to the camera body 100 (NO in step S304), the camera microcomputer 101 proceeds to the process in step S306.

  In the AF mode (YES in step S306), the camera microcomputer 101 performs focus detection by a so-called phase difference detection method using the focus detection circuit 107 (step S307). At this time, which of the plurality of distance measuring points is determined as the distance measuring point is determined according to the point set by the input unit 112 or the shooting mode. Or you may make it determine using an automatic selection algorithm on the basis of near point priority.

  Subsequently, the camera microcomputer 101 obtains the driving amount of the lens based on the focus detection result by the focus detection circuit 107 (step S308). Then, the camera microcomputer 101 sends the lens driving amount to the lens microcomputer 201. The lens microcomputer controls the lens driving unit 203 according to the lens driving amount to drive the lens group 202 to the in-focus position. When the lens is in focus, the lens microcomputer 201 obtains information on the subject distance D indicating the distance to the subject existing at the distance measuring point by the encoder 204 and sends the information on the subject distance D to the camera microcomputer 101.

  Subsequently, the camera microcomputer 101 divides the image into a plurality of areas (for example, 12 areas), and obtains a subject luminance value from the photometry circuit 106 for each area (step S309). If it is not the AF mode (NO in step S306), that is, if it is the MF mode, the camera microcomputer 101 proceeds to the process of step S309.

  Next, the camera microcomputer 101 performs gain setting by the gain switching circuit 108 according to the gain set by the input unit 112 (step S310). For example, gain setting is ISO sensitivity setting. Further, the camera microcomputer 101 sends information regarding gain setting to the flash microcomputer 310.

  Subsequently, the camera microcomputer 101 determines the exposure value EVs according to the subject luminance value EVb for each of the plurality of areas (step S311). Then, the camera microcomputer 101 determines whether or not the flash microcomputer 310 has output a charging completion signal (step S312). Then, the camera microcomputer 101 stores the determination result (charge determination result) in the built-in memory.

  When the flash microcomputer 310 is outputting a charge completion signal (YES in step S312), the camera microcomputer 101 determines a shutter speed Tv and an aperture value Av suitable for performing flash photography based on the subject brightness value. (Step S313). On the other hand, if the flash microcomputer 310 does not output a charging completion signal (NO in step S312), the camera microcomputer 101 sets a shutter speed Tv and an aperture value Av suitable for performing natural light photography based on the subject brightness value. Determination is made (step S314).

  After the processing of step S313 or S314, the camera microcomputer 101 sends information about other strobes to the strobe microcomputer 310 (step S315). Then, the camera microcomputer 101 determines whether or not the shutter button is fully pressed (here, whether or not SW2 is on) (step S316). If SW2 is off (OFF in step S316), camera microcomputer 101 returns to the process in step S302. If SW2 is on (ON in step S316), the camera microcomputer 101 proceeds to a release operation described later.

  FIG. 8 is a flowchart for explaining the processing of the camera microcomputer 101 in the release operation when the strobe is attached.

  When SW2 is turned on, when the strobe 300 is attached, the camera microcomputer 101 performs preliminary light emission by the strobe microcomputer 310 in order to obtain luminance information relating to the subject. Then, the camera microcomputer 101 obtains a subject luminance value (photometric value) for each of a plurality of areas (photometric areas) using a photometric sensor (step S401). Subsequently, the camera microcomputer 101 obtains the corrected preliminary light emission amount H from the flash microcomputer 310 (step S402).

  The camera microcomputer 101 performs weighting calculation for each photometric area (step S403). At this time, the camera microcomputer 101 obtains the reference photometric value FR at the time of preliminary light emission according to the following equation (4), for example, according to the corrected preliminary light emission amount H and the subject distance D.

FR = −log ₂ (D) × 2 + H (4)
The reference photometric value FR indicates an expected value of the photometric value obtained by the photometric sensor when the preliminary light emission amount is the corrected preliminary light emission amount H at the subject distance D when the subject has a standard reflectance. That is, assuming that the subject existing in each area has a standard reflectance, the distance to the subject is the distance to the main subject existing at the distance measuring point in the area where the photometric value is close to the reference photometric value FR. It is close to the subject distance D. For this reason, the camera microcomputer 101 increases the weighting of an area having a value close to the reference photometric value FR among the photometric values for each of a plurality of areas. On the other hand, an area having a value far from the reference photometric value FR is reduced in weight, and the photometric value at the time of preliminary light emission is weighted to obtain a weighted calculation value. By obtaining the weighted calculation value in this way, it is possible to calculate the proper main light emission amount for the main subject and the subject located near the main subject.

  Subsequently, the camera microcomputer 101 calculates the main light emission amount according to the weighted calculation value, the shutter speed, and the aperture value at the time of preliminary light emission (step S404). Since the calculation of the main light emission amount is known, the description is omitted.

  Next, the camera microcomputer 101 raises the main mirror 104 prior to the exposure operation, and moves the main mirror 104 out of the photographing optical path (step S405). Then, the camera microcomputer 101 sends a command to the lens microcomputer 201 to obtain an aperture value AV corresponding to the determined exposure value EVs. Further, in order to obtain the determined shutter speed TV, the shutter 103 is controlled via a shutter control circuit (not shown) (step S406).

  Subsequently, in synchronization with the fully opening of the shutter 103, the camera microcomputer 101 gives a light emission command signal for main light emission to the flash microcomputer 310 via the interface signal line SC (step S407). As a result, the strobe 300 emits light.

  As described above, when a series of exposure operations is completed, the camera microcomputer 101 lowers the main mirror 104 that has been moved away from the photographing optical path and arranges it again in the photographing optical path (step S408).

  Next, the camera microcomputer 101 reads an image signal from the image sensor 102, amplifies the image signal with a gain set in the gain switching circuit 108, and supplies the amplified signal to the A / D converter 109. The digital signal (pixel data) output from the A / D converter 109 is subjected to predetermined signal processing such as white balance in the digital signal processing circuit 111 (step S409: development processing). Thereafter, the camera microcomputer 101 stores the image data in a memory (not shown) and ends the routine for one image.

  As described above, in the first embodiment of the present invention, the corrected preliminary light emission amount is calculated according to the transmittance of the color filter mounted on the strobe, so that the exposure is appropriately adjusted even when the color filter is mounted. Can be controlled.

  Note that the method for acquiring the transmittance of the color filter mounted on the strobe is not limited to the above-described method. For example, a table in which color filter types and transmittances stored in advance are associated with each other and the color filter type is identified. A method of obtaining based on the result may be used. The method for identifying the type of color filter may be, for example, the method described in Patent Document 1.

  Further, a table is stored in the ROM or EEPROM of the camera body 100 as shown in FIG. 6, and the camera microcomputer 101 determines the light emission reduction amount based on the information transmitted from the strobe and calculates the corrected preliminary light emission amount. It may be.

[Second Embodiment]
Next, an example of an imaging apparatus equipped with the flash device according to the second embodiment of the present invention will be described. Note that the configuration of the imaging apparatus in the second embodiment is the same as that of the imaging apparatus shown in FIG. In the second embodiment, the calculation of the corrected preliminary light emission amount described in FIG. 4 is different from that in the first embodiment.

  FIG. 9 is a flowchart for explaining calculation of the corrected preliminary light emission amount in the imaging apparatus according to the second embodiment of the present invention. In FIG. 9, the same steps as those described in FIG.

  The built-in memory of the flash microcomputer 310 stores predetermined three primary color information (three primary color information when there is no color filter) as reference three primary color information (r0, g0, b0). The reference three primary color information (r0, g0, b0) is obtained by receiving the light from the light source 402 with the color sensor 403 in the state where the color filter is not mounted, and performing the processes of steps S204 and S205 shown in FIG. 3 primary color information obtained as a result.

  After performing the process of step S205, the flash microcomputer 310 reads the reference three primary color information (r0, g0, b0) stored in the built-in memory (step S505). Subsequently, the stroboscopic microcomputer 310 obtains the light reduction amount Gw of the color filter as follows (step S506).

  For example, the stroboscopic microcomputer 310 obtains chromaticity information (Brc, Cxc, Cyc) of transmitted light that passes through the color filter 401 according to Expression (5) based on the corrected three primary color information (rc, gc, bc). Further, the stroboscopic microcomputer 310 obtains chromaticity information (Br0, Cx0, Cy0) of the light from the light source 402 according to Expression (6) based on the reference correction three primary color information (r0, g0, b0).

  Here, if the coefficients M11 to M33 are appropriately selected, the corrected three primary color information (rc, gc, bc) can be converted into lightness values (lightness information) Brc and Br0 representing the brightness of the transmitted light. . The corrected three primary color information (rc, gc, bc) is converted into chromaticity values (chromaticity information) Cxc, Cx0, Cyc, and Cy0 representing the chromaticity of transmitted light in two axes (xy chromaticity diagram). can do.

  Next, the flash microcomputer 310 extracts the brightness components Brc and Br0 from the chromaticity information obtained as described above. Then, the flash microcomputer 310 obtains the filter light reduction amount Gw by the following equation (7).

Gw = log ₂ (Brc / Br0) (7)
Since the filter light reduction amount Gw obtained in step S506 is calculated based on the light from the light source 402, the value is different from the light reduction amount when light is emitted from the discharge tube 307. Accordingly, the stroboscopic microcomputer 310 corrects the filter light reduction amount Gw so as to obtain a light reduction amount due to the spectral characteristics of the discharge tube 307, and obtains a light reduction amount (light emission reduction amount: also called strobe light reduction amount) G of the flash light (step S507). ).

  Here, the stroboscopic microcomputer 310 calculates the stroboscopic light reduction amount G based on the filter light reduction amount Gw and the spectral characteristics of the discharge tube 307, the light source 402, and the color sensor 403.

  FIG. 10 is a diagram showing the spectral characteristics of the discharge tube 307, the light source 402, and the color sensor 403 as shown in the discharge tube shown in FIG.

  As shown in FIG. 10, the spectral characteristics in the emitted light of the discharge tube 307 are different from the spectral characteristics in the emitted light of the light source 402. Therefore, when calculating the strobe light reduction amount G due to the mounting of the color filter, it is necessary to consider the difference in spectral characteristics.

  Now, let Xe be the spectral coefficient of the discharge tube 307, WL be the spectral coefficient of the light source 402, and Cs be the spectral coefficient of the color sensor 403. The wavelength of light is λ.

  At this time, the flash microcomputer 310 calculates the flash light reduction amount G based on the following equation (8).

  In step S210, the flash microcomputer 310 obtains the corrected preliminary light emission amount H based on the above-described equation (3), and ends the calculation of the corrected preliminary light emission amount.

  In the above-described embodiment, the strobe microcomputer 310 calculates the corrected preliminary light emission amount. However, the camera microcomputer 101 may calculate the corrected preliminary light emission amount according to the transmittance of the color filter. Good. For example, information regarding the transmission characteristics of the color filter necessary for calculating the corrected preliminary light emission amount is transmitted from the strobe to the imaging device, and the camera microcomputer 101 calculates the corrected preliminary light emission amount based on the information transmitted from the strobe. May be. In that case, the camera microcomputer 101 may perform at least a part of steps S204, 505, 506, 507, and 210 in accordance with information transmitted from the strobe. For example, when information regarding the amount of light that is attenuated by the color filter of the strobe light is transmitted from the strobe as information regarding the transmission characteristics of the color filter, step S210 may be performed by the camera microcomputer 101.

  As described above, also in the second embodiment of the present invention, since the transmittance of the color filter mounted on the strobe is detected and the corrected preliminary light emission amount is calculated according to the transmittance, the color filter The exposure can be properly controlled even during the mounting.

  If the reference photometric value FR is not obtained based on the corrected preliminary light emission amount H, the photometric value in an area where the subject distance is close to the subject distance D and has a standard reflectance is reduced by the color filter. It gets smaller by that amount. Accordingly, the photometric value of the area where the subject is significantly shorter than the subject distance D or the area where the subject having a high reflectance exists is closer to the reference photometric value FR. For this reason, when the weighting for such an area is set large, it is impossible to calculate the proper main light emission amount for the main subject.

  Therefore, instead of detecting the transmittance of the color filter mounted on the strobe and calculating the corrected preliminary light emission amount according to the transmittance, the photometric value at the time of preliminary light emission is corrected according to the transmittance of the color filter. It doesn't matter. Alternatively, when calculating the main light emission amount by obtaining the photometric value of the reflected light of the preliminary light emission based on the photometric value at the time of preliminary light emission and the photometric value at the time of non-light emission, the photometry of the reflected light of the preliminary light emission is calculated. The value may be corrected according to the transmittance of the color filter.

  When correcting the metering value at the time of preliminary light emission or the reflected light value of the preliminary light emission, the correction is equivalent to the metering value at the time of preliminary light emission when the color filter is not attached or the metering value of the reflected light value of the preliminary light emission. It becomes the value of. Therefore, by determining the weighting of each photometric area based on the corrected photometric value, it is possible to increase the weighting for the main subject and the area where the subject located near the main subject exists. However, when the main light emission amount is calculated by obtaining a weighted calculation value based on the corrected photometric value, the appropriate light emission amount for the main subject and a subject located near the main subject when the color filter is not attached. Will be calculated. As a result, the amount of light that reaches the subject after being attenuated by the color filter becomes smaller than the appropriate amount of light. Therefore, when calculating the actual light emission amount, a weighted calculation value based on a photometric value at the time of preliminary light emission before correction or a photometric value of the reflected light of the preliminary light emission using weighting determined based on the photometric value after correction. Need to get. Alternatively, it is necessary to correct the main light emission amount calculated using the weighted calculation value based on the corrected photometric value according to the transmittance of the color filter.

  In the above case, the photometric value and the main light emission amount may be corrected using the camera microcomputer 101 or the like, and the lighting device relates to the transmission characteristics of the preliminary light emission by the color filter as information about the transmission characteristics of the mounted color filter. Information or the like may be transmitted to the imaging device.

  In addition, any optical member that can change the color characteristics of transmitted light and can be mounted in front of the light emitting unit of the lighting device may be used as an optical accessory that changes the color characteristics of light transmitted by one member. I do not care.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  The present invention can also be realized by executing the following processing. That is, software (program) for realizing the functions of the above-described embodiments is supplied to a system or apparatus via a network or various recording media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 100 Camera body 101 Camera microcomputer 300 Strobe 310 Strobe microcomputer 350 Strobe light emission part 324 Filter detection part 400 Filter holder 401 Color filter 402 Light source 403 Color sensor

Claims (5)

An illuminating device that can be attached to the front of the light-emitting unit and attachable to and detachable from the imaging device, and an optical accessory that changes the color characteristics of the transmitted light.
Obtaining means for obtaining information about the characteristics of the optical accessory attached in front of the light emitting unit;
Based on the information about the characteristics of the optical accessory acquired by the acquisition unit, the corrected preliminary light emission amount corrected according to the amount of light reduced by the optical accessory with respect to the preliminary light emission amount that is the light emission amount at the time of preliminary light emission Calculating means for calculating information representing
Transmitting means for transmitting information representing the corrected preliminary light emission amount calculated by the calculating means to the mounted imaging device;
A lighting device comprising: A light source;
A light receiving means,
The acquisition means, wherein the light transmitted through the optical accessory emitted from the light source based on the light reception result of light received by said light receiving means, to claim 1, characterized in that to obtain information on the characteristics of the optical accessory Lighting equipment. Storage means for storing in advance information associating information about color characteristics of light emitted from the light source and transmitted through the optical accessory with information about characteristics of the optical accessory;
The acquisition unit acquires information on the characteristics of the optical accessory based on information on color characteristics of light transmitted through the optical accessory based on a light reception result of the light receiving unit and information stored in the storage unit. The lighting device according to claim 2 . An imaging system including an illumination device capable of attaching an optical accessory that changes a color characteristic of transmitted light in front of a light emitting unit, and an imaging device,
The lighting device includes:
Obtaining means for obtaining information about the characteristics of the optical accessory attached in front of the light emitting unit;
Based on the information about the characteristics of the optical accessory acquired by the acquisition unit, the corrected preliminary light emission amount corrected according to the amount of light reduced by the optical accessory with respect to the preliminary light emission amount that is the light emission amount at the time of preliminary light emission Calculating means for calculating information representing
Transmission means for transmitting information representing the corrected preliminary light emission amount calculated by the calculation means,
The imaging device
Photometric means;
Receiving means for receiving information representing the corrected preliminary light emission amount;
Based on the photometric value obtained by the photometric means and the information indicating the corrected preliminary light quantity received by the receiving means, the main light emission amount of the illumination apparatus is obtained by performing preliminary light emission with the preliminary light emission amount by the illumination device. A determination means for determining
An imaging system comprising: The photometric means can obtain photometric values of a plurality of different areas in the image,
The determination unit performs preliminary light emission with the preliminary light emission amount by the lighting device, and represents the corrected preliminary light emission amount received by the reception unit for each of the photometric values of a plurality of different areas obtained by the photometry unit. 5. The imaging system according to claim 4, wherein the main light emission amount is determined by performing weighting according to a comparison result with a reference photometric value based on information.