JP2008079136A - Imaging device and its control method, program, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform flash photography suitable for various conditions such as differences in distance to a subject and a reflection factor. <P>SOLUTION: An imaging device which picks up an image by converting an optical image of a subject into an electric signal comprises an imaging element A which accumulates and reads out electric charges with time lags by lines, a flash unit which irradiates the subject with light during photography, a light emission control means of starting auxiliary light emission by the flash unit at the start of the storage of the electric charges by the imaging element A and repeatedly making the flash unit emit light until the read of the electric charges is completed while varying an auxiliary light emission level, a calculating means of calculating a primary light emission level by the flash unit based on the image obtained by auxiliary light emission, and a photography control means of picking up an image by making the flash unit emit light at the calculated primary light emission level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flash photography technique in an imaging apparatus.

  2. Description of the Related Art Conventionally, in a photographing device using a CCD (charge coupled device), prior to photographing, a strobe is preliminarily emitted before photographing, and the main (main) light emission amount is obtained from the image at that time. Shooting is widely performed.

  FIG. 11 illustrates an interline CCD as a configuration of a conventional image sensor.

  In FIG. 11, reference numeral 501 denotes a photodiode (PD) for photoelectric conversion. A vertical transfer path 502 transfers the charge of the photodiode 501. Reference numeral 503 denotes a horizontal transfer path for transferring the charges transferred from the vertical transfer path 502 for each line. Reference numeral 504 denotes an output amplifier that uses the charge for each pixel transferred from the horizontal transfer path 503 as a voltage signal.

  The illustrated image sensor is composed of two regions 505 and 506. One area 505 is an effective imaging area for converting an optical image to be imaged into a charge signal. The other region 506 has the same configuration as the region 505, but is a light shielding region (OB (Optical Black)) that is shielded by an aluminum layer or the like and obtains a black level.

  The CCD shown in the figure moves the charges photoelectrically converted by the photodiode 501 collectively to the vertical transfer path 502, thereby electrically controlling the accumulation time and electrically controlling the exposure amount. It is possible to have a function called an electronic shutter.

  FIG. 12 is a timing chart showing the flash photographing process in the CCD.

  12A is a light emission waveform of a strobe, FIG. 12B is an accumulation state of the photodiode 501, and FIG. 12C is a transfer signal of the charge of the photodiode 501 to the vertical transfer path 502. (D) is a signal for transferring the electric charge of the vertical transfer path 502 to the horizontal transfer path 503, and one pixel of each column is transferred to the horizontal transfer path 503 all at once. (E) is a horizontal transfer signal for transferring the charge of the horizontal transfer path 503 to the output amplifier 504 pixel by pixel. In synchronization with this signal, the output voltage of the output amplifier 504 is A / D converted to an image (not shown). Digital image data is obtained by writing to the memory.

  Next, the strobe light emission sequence will be described with reference to FIG.

  In FIG. 12, accumulation of the photodiode 501 is started at t0 (B), and the strobe is pre-flashed with a predetermined amount of light (A). Next, at t1, the accumulation of the photodiode 501 is terminated (B), and the charge of the photodiode 501 is transferred to the vertical transfer line 502 (C). Next, the charge corresponding to one row as the image signal transferred to the vertical transfer line 502 is transferred to the horizontal transfer path 503 (D). Thereafter, the charge for one row transferred to the horizontal transfer line 503 is transferred to the output amplifier 504 (E). When the transfer for one row is completed, the next row of the vertical transfer path 502 is similarly moved to the horizontal transfer path 503 at t3 to perform horizontal transfer. This operation is performed for all lines.

  When all the image signals have been transferred, the main light emission amount of the strobe is calculated from the luminance of the image transferred to the image memory as described above. Then, accumulation of the photodiode 501 is started at t5, and the strobe is emitted with the calculated predetermined light amount. After the predetermined light amount is emitted, the strobe light emission is stopped. Next, at t6, the accumulation of the photodiode 501 is terminated, the actual captured image is read out, and thereafter the actual captured image is read in the same manner as in the pre-flash.

  Recently, a CMOS sensor has attracted attention as an image sensor that replaces a CCD. The biggest feature is that the circuit is composed of MOS transistors, so that power consumption is very small, and a plurality of power supplies including negative voltages are not required for charge transfer as in a CCD.

  In addition, a photodiode that performs photoelectric conversion is called a dark current, and a current is generated even when no light is applied due to the ambient temperature, and the amount thereof increases twice as the temperature increases by 8 ° C. Therefore, low power consumption means less heat generation, and especially when the exposure time is long, the CMOS sensor is characterized by very little image noise compared to the CCD.

  FIG. 13 illustrates a circuit configuration of the CMOS sensor.

  In FIG. 13, reference numeral 601 denotes a photodiode (hereinafter referred to as a PD section) that converts light into electric charges and accumulates electric charges photoelectrically converted in accordance with the exposure amount. Reference numeral 602 denotes a floating diffusion (hereinafter referred to as an FD portion). Reference numeral 603 denotes a transfer gate (hereinafter referred to as a TX unit), which transfers charges to the FD unit 602 in the next stage for signal reading upon completion of accumulation. Reference numeral 604 denotes a reset gate (hereinafter referred to as an RS unit), which resets the FD unit 602 and the PD unit 601. Reference numeral 605 denotes a floating diffusion amplifier (hereinafter referred to as FD amplifier), which converts the electric charge photoelectrically converted by the PD unit 601 into a voltage. Reference numeral 606 denotes a selection gate (hereinafter referred to as a SEL unit), which is a selection switch for reading a signal from the FD unit 602.

  Each of the components 601 to 606 described above forms one pixel, and this circuit is provided for the number of pixels.

  Next, charge accumulation and charge read operations by the CMOS sensor will be described with reference to FIG.

  In FIG. 13, first, the PD unit 601 and the FD unit 602 are once reset by turning on the TX unit 603 and the RS unit 604 before starting the charge accumulation.

  Next, accumulation is started when the TX unit 603 and the RS unit 604 are turned off. At this time, the electric charge of the FD unit 602 is zero, the SEL unit 606 is turned on, the zero electric charge is read to the vertical output line 625, and the reset level is reset to the capacitor 608 of the circuit module existing in the SN circuit by the number of columns. Remember as.

  Next, when a predetermined exposure time has elapsed, the TX unit 603 is turned on, and the charge accumulated in the PD unit 601 is transferred to the FD unit 602 through the TX unit 603. Further, the SEL unit 606 is turned on, the output voltage corresponding to the accumulated charge is read out to the vertical output line 625, and the output voltage is stored in the capacitors 608 and 609 via the switches 610 and 611. Thus, the respective signal levels and reset levels are stored in the capacitors 608 and 609. The readout switches 615 and 616 are turned on and input to the differential amplifier 623 to obtain an accumulated signal from which the noise level is deleted.

  Next, the charge reading operation of the image sensor composed of the CMOS sensor will be described.

  FIG. 14 is a diagram for explaining the timing of charge reading and strobe light emission by a conventional CMOS sensor.

  In FIG. 14, A is an image sensor composed of a CMOS sensor, B is a strobe light emission waveform, and C is a reset release (charge accumulation) timing of the image sensor A, and at the same time the reset is released, accumulation of the charge of the subject light is started. D is the accumulation end timing, and the period from C to D corresponds to the charge accumulation time. In the case of time difference sequential readout, accumulation is performed while shifting the time for each line sequentially from the top of the image sensor A at time t0, and charges (pixel data) are sequentially read out from the upper line at time t2 in the period E. . This shifting time corresponds to the readout time TH for one line of the image sensor A.

As shown in FIG. 14, in order to synchronize with the strobe light emission B, it is necessary to always take time for all lines to be exposed simultaneously as in the period t1 to t2, and the strobe is synchronized as shown in B during this period. The subject image emitted by the flash and illuminated by the strobe can be captured. Then, similar to the above-described strobe photographing with the CCD, using this captured image, the overexposure or underexposure is calculated from the strobe reflected light, the strobe emission amount during the main photographing is calculated, and the strobe photographing is performed.
JP 2004-363666 A

  When the main light emission amount is determined by obtaining the subject luminance from the subject reflected light by the pre-light emission described in FIGS. 12 to 14 by an image sensor such as a CCD or CMOS sensor, depending on the distance from the subject and the reflectance, The dynamic range will be exceeded. In this case, the subject brightness cannot be measured correctly, and the flash photography cannot be performed with an appropriate light amount.

  For example, when pre-flash is performed with strobe emission equivalent to guide number 8 (GV4), if the lens aperture value is 4.0 (AV4), the light quantity is appropriate for a subject with a distance of 2 m. On the other hand, since the linearity of the image sensor is about six steps in width with the proper light quantity as the center, the dynamic range of the image sensor exceeds other than 0.7 m to 5.6 m with 2 m as the proper light quantity.

  In addition, since the reach distance of the strobe is defined based on a reflectance of 23%, for example, in the case of white clothes with a reflectance of 90%, log 2 (90/23) = 1.97 with respect to the reflectance of 23%. [EV] Reflected light brightness is high. For this reason, the dynamic range is exceeded within the subject distance of 1.4 m.

  On the other hand, when the subject is black clothes with a reflectivity of about 5%, the log2 (5/23) = − 2.3 [EV] reflected light luminance is low, so that the dynamic range of the image sensor is increased at a subject distance of 3.5 m or more. It will exceed.

  In order to avoid such inconvenience, the dynamic range for subject luminance metering can be expanded by performing pre-emission a plurality of times by changing the light intensity or light quantity during pre-emission. However, since the time for light emission and imaging is required by the number of times of pre-light emission, the release time lag is extended. Further, since pre-emission is performed a plurality of times, extra energy is consumed accordingly.

  The present invention has been made in view of the above problems, and its purpose is to determine various main flash amounts from subject brightness obtained by pre-flash and perform various shooting such as distance to the subject and difference in reflectance. It is to realize a technology that enables appropriate flash photography for the conditions.

  In order to solve the above-described problems and achieve the object, the present invention is an imaging apparatus that captures an image by converting an optical image of a subject into an electrical signal, and stores charge while shifting the time for each line. An image pickup device that sequentially performs reading, a flash device that irradiates a subject with light at the time of shooting, and a preliminary light emission by the flash device at the start of charge accumulation by the image pickup device and a standby until reading of the charge is completed Light emission control means for repeatedly emitting light from the flash device while changing the light emission level, calculation means for calculating a main light emission level by the flash device based on an image obtained by the preliminary light emission, and the calculated main light emission level And a photographing control means for capturing an image by causing the flash device to emit light.

  The present invention also includes an imaging device that sequentially stores and reads out charges while shifting the time for each line, and a flash device that irradiates light to the subject at the time of shooting. A method of controlling an imaging apparatus that converts an image into an image and captures an image, wherein at the start of charge accumulation by the imaging element, preliminary light emission by the flash device is started and a preliminary light emission level is changed until reading of the charge is completed. A preliminary light emission step for causing the flash device to repeatedly emit light, a calculation step for calculating a main light emission level by the flash device based on an image obtained by the preliminary light emission, and the flash device at the calculated main light emission level. And a photographing step for capturing an image by emitting light.

  According to the present invention, when the main flash amount is determined from the subject brightness obtained by the pre-flash and the flash shooting is performed, the proper flash shooting is performed for various conditions such as the distance from the subject and the difference in reflectance. It becomes possible.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment.

[Overall camera configuration (Fig. 1)]
FIG. 1 is a block diagram of an imaging apparatus according to an embodiment of the present invention.

  In FIG. 1, the imaging apparatus of the present embodiment is a digital still camera, for example, and 100 is a camera body.

  Reference numeral 1 denotes a main mirror, which is obliquely installed in the photographing optical path in the finder observation state and retracts out of the photographing optical path in the photographing state. Further, the main mirror 1 constitutes a half mirror, and in a state where it is obliquely provided in the photographing optical path, approximately half of the light beam from the subject is transmitted to the focus detection unit 8 described later. Reference numeral 2 denotes a focusing plate, on which a subject image formed by a focusing lens 201 described later is projected.

  Reference numeral 3 denotes a sub-mirror, which is tilted along with the main mirror 1 in the photographing optical path in the finder observation state and retracts out of the photographing optical path in the photographing state. The sub mirror 3 bends the light beam transmitted through the oblique main mirror 1 and guides it to the focus detection unit 8.

  4 is a finder optical path changing pentaprism, and 5 is an eyepiece. The photographer can observe the subject by observing the focus plate 2 from the window of the eyepiece 5 through the viewfinder observation screen. This state is called an optical finder mode (OVF mode).

  Reference numerals 6 and 7 are an imaging lens and a photometric sensor for measuring the luminance of the object in the viewfinder observation screen. Since the photometric sensor 7 has a known logarithmic compression circuit inside, its output is logarithmically compressed. It becomes. Reference numeral 8 denotes a known phase difference type focus detection unit.

  Reference numeral 9 denotes a focal plane shutter (hereinafter referred to as a shutter). Reference numeral 14 denotes an image sensor composed of a CMOS sensor, which has a configuration similar to that shown in FIG.

  Reference numeral 16 denotes an A / D converter that converts an analog signal output of the image sensor 14 into a digital signal.

  A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16, and the D / A converter 26, and is controlled by the memory control circuit 22 and the system controller 50.

  An image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22.

  The image processing circuit 20 performs predetermined calculation processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained calculation result.

  A memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32.

  The data of the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or the data of the A / D converter 16 is directly passed through the memory control circuit 22. It is.

  Reference numeral 24 denotes an image display memory, 26 denotes a D / A converter, and 28 denotes an image display unit composed of a TFT LCD or the like. Display image data written in the image display memory 24 is imaged via the D / A converter 26. The data is output and displayed on the display unit 28.

  When the captured image data is sequentially displayed on the image display unit 28 with the main mirror 1 and the sub mirror 3 up and the shutter 9 opened, the electronic viewfinder function is realized. This state is called an electronic viewfinder mode (EVF mode) with respect to the optical viewfinder mode.

  Reference numeral 30 denotes a memory for storing photographed image data, which has a sufficient storage capacity for storing a predetermined number of still images and a predetermined time of moving images. The memory 30 can also be used as a work area for the system controller 50.

  Reference numeral 32 denotes a compression / decompression circuit that compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads image data stored in the memory 30, performs compression processing or decompression processing, and stores the processed data in the memory 30. Write to.

  Reference numeral 40 denotes a shutter control unit that controls the shutter 9, and reference numeral 41 denotes a mirror control unit that includes a motor and a drive circuit for moving the main mirror 1 up or down.

  Reference numeral 50 denotes a system controller that controls the entire camera body 100, and reference numeral 52 denotes a memory that stores constants, variables, programs, and the like for operation of the system controller 50.

  Reference numeral 54 denotes a display unit such as a liquid crystal display device or a speaker that displays an operation state, a message, or the like using characters, images, sounds, or the like in accordance with execution of a program by the system controller 50. The display unit 54 is installed in a single or a plurality of locations near the operation unit of the camera body 100 so as to be easily visible, and is configured by, for example, a combination of an LCD, an LED, a sounding element, and the like. Further, the display unit 54 displays some of the functions on the finder screen in the OVF mode.

  Among the display contents of the display unit 54, what is displayed on the LCD or the like includes single shot / continuous shooting display, self-timer display, compression rate display, number of recorded pixels, number of recorded images, number of remaining images that can be captured, and the like. is there. In addition, shutter speed display, aperture value display, exposure compensation display, strobe display, red-eye reduction display, macro shooting display, buzzer setting display, clock battery level display, battery level display, error display, multi-digit number Information display. Furthermore, there are a display state of the recording medium 120, a communication I / F operation display, a date / time display, and the like.

  Among the display contents of the display unit 54, what is displayed on the viewfinder screen in the OVF mode includes in-focus display, camera shake warning display, strobe charge display, shutter speed display, aperture value display, exposure correction display, and the like. .

  Reference numeral 56 denotes an electrically erasable / recordable nonvolatile memory such as an EEPROM.

  Reference numerals 60, 62, 64, 66, 68, and 70 are operation units for inputting various operation instructions of the system controller 50, and one or a plurality of switches, dials, touch panels, pointing by line-of-sight detection, voice recognition devices, and the like. Consists of

  Here, these operation units will be specifically described.

  Reference numeral 60 denotes a mode dial switch, which can switch and set each function mode such as power OFF, shooting mode (still image shooting mode, moving image shooting mode), playback mode, deletion mode, PC connection mode, and the like.

  Reference numeral 62 denotes a shutter switch SW1, which is turned on during the operation of a shutter button (not shown) and instructs the start of operations such as AF (autofocus) processing and AE (automatic exposure) processing.

  Reference numeral 64 denotes a shutter switch SW2, which is turned on when the operation of a shutter button (not shown) is completed, and an exposure process for writing a signal read from the image sensor 14 to the memory 30 via the A / D converter 16 and the memory controller 22. Instruct the start of operation. Further, it instructs the start of the development processing operation using the calculation in the image processing circuit 20 and the memory control circuit 22. Further, the image data is read from the memory 30, compressed by the compression / decompression circuit 32, and an instruction to start the recording process for writing the image data to the recording medium 120 is given.

  Reference numeral 66 denotes a finder mode setting switch, which can select the above-described OVF mode and EVF mode at the time of shooting. When the EVF mode is set, the main mirror 1 and the sub mirror 3 are retracted from the photographing optical path, the shutter 9 is opened, and an image picked up by the image sensor 14 is displayed on the image display unit 28 at all times.

  Reference numeral 68 denotes a quick review ON / OFF switch, which can set a quick review function for automatically reproducing image data taken immediately after photographing. In the present embodiment, in particular, a function for setting a quick review function when the image display unit 28 is turned off is provided.

  70 includes various buttons and a touch panel, and includes a menu button, a set button, a macro button, a multi-screen playback page break button, a single shooting / continuous shooting / self-timer switching button, and the like. In addition, the menu movement + (plus) button, menu movement-(minus) button, playback image movement + (plus) button, playback image movement-(minus) button, shooting quality selection button, exposure compensation button, date / time There are time setting buttons.

  A power control unit 80 includes a power detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like. The power supply control unit 80 detects the presence / absence of a battery, the type of battery, and the remaining battery level, controls the DC-DC converter based on the detection result and an instruction from the system controller 50, and supplies a necessary voltage for a necessary period , And supplied to each unit including the recording medium.

  Reference numerals 82 and 84 denote connectors, 86 denotes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiMH battery or a Li battery, an AC adapter, or the like.

  Reference numeral 90 denotes an interface with a recording medium such as a memory card or a hard disk. A connector 92 connects to a recording medium such as a memory card or a hard disk. A recording medium attachment / detachment detection unit 98 detects whether or not the recording medium 120 is attached to the connector 92.

  The interface and connector are configured using a PCMCIA card, a CF (Compact Flash (registered trademark)) card, or the like that conforms to a standard.

  A communication unit 72 has various communication functions such as RS232C, USB, IEEE1394, and wireless communication.

  Reference numeral 73 denotes a connector for connecting the camera body 100 to another device by the communication unit 72 or an antenna in the case of wireless communication.

  Reference numeral 120 denotes a recording medium such as a memory card or a hard disk. The recording medium 120 includes a recording unit 122 composed of a semiconductor memory, a magnetic disk, and the like, an interface 124 with the camera body 100, and a connector 126 connected to the camera body 100 via a connector 92.

  Reference numeral 399 denotes a communication line for performing communication between a lens apparatus 200, which will be described later, and the system controller 50 on the camera side, and 499, a communication line for performing communication between a strobe apparatus 400, which will be described later, and the system controller 50 on the camera side.

  Next, the lens device 200 will be described.

  Reference numeral 201 denotes a focusing lens for forming a subject image on the image sensor 14 and performing focus adjustment. Reference numeral 202 denotes a focus drive actuator for driving the focusing lens 201 in the optical axis direction to focus. Reference numeral 211 denotes a focus control circuit that controls the focus drive actuator 202 based on a command from the lens control microcomputer 206.

  A distance detection unit 203 includes an encoder for detecting a subject distance from the position of the focusing lens 201. Reference numeral 204 denotes an aperture for adjusting the amount of light at the time of shooting. Reference numeral 250 denotes an aperture drive actuator. Reference numeral 205 denotes an aperture control circuit that controls the aperture drive actuator 250 based on a command from the lens control microcomputer 206.

  Reference numeral 207 denotes a zooming lens for adjusting the focal length for zooming. Reference numeral 208 denotes a zoom drive actuator for driving the zooming lens 207 in the optical axis direction to adjust the focal length electrically. A zoom control circuit 212 controls the zoom drive actuator 207.

  Reference numeral 206 denotes a lens control microcomputer that controls the above-described focus drive, aperture drive, and the like, and controls communication with the system controller 50 on the camera side. The lens device 200 is detachably attached to the camera body 100 via the lens mount 209, and is electrically connected to the camera body 100 by a connector 210 including a serial communication line and a power source.

  A strobe device 400 is connected to the camera body 100 via a hot shoe 410 and a contact group 411.

[Internal configuration of strobe device (Fig. 2)]
Next, the internal configuration of the flash device 400 will be described with reference to FIG.

  In FIG. 2, 401 is a power supply battery. A DC / DC converter (charging circuit) 402 boosts the battery voltage to several hundred volts.

  Reference numeral 403 denotes a main capacitor for accumulating light emission energy. Reference numerals 404 and 405 denote resistors, which divide the voltage of the main capacitor 403 into a predetermined ratio.

  Reference numeral 406 denotes a coil for limiting the emission current, reference numeral 407 denotes a diode for absorbing a counter electromotive voltage generated when emission is stopped, and reference numeral 412 denotes an Xe (xenon) tube. Reference numeral 413 denotes a trigger generation circuit, and reference numeral 414 denotes a light emission control circuit such as an IGBT.

  A data selector 430 selects D0, D1, and D2 and outputs them to Y by a combination of two inputs Y0 and Y1. Reference numeral 431 denotes a light emission level control comparator for flat light emission, and reference numeral 432 denotes a light emission amount control comparator for flash light emission.

  Reference numeral 435 denotes a light receiving sensor composed of a photodiode for controlling flat light emission, and monitors the light output of the Xe tube 412. Reference numeral 434 denotes a photometric circuit that amplifies a minute current flowing through the photodiode 435 and converts the photocurrent into a voltage.

  Reference numeral 438 denotes a light receiving sensor composed of a photodiode for controlling flash emission, which monitors the light output of the Xe tube 412. Reference numeral 436 denotes an integral photometry circuit for logarithmically compressing the photocurrent flowing through the photodiode 438 and compressing and integrating the light emission amount of the Xe tube 412.

  A flash control microcomputer 440 controls the operation of the entire flash device 400, and a contact group 411 is provided on the hot shoe for communicating with the camera body 100.

  Next, each terminal of the flash control microcomputer 440 will be described.

  CNT is a control output terminal that controls charging of the DC / DC converter 402. CLK is an input terminal for a synchronous clock for serial communication with the camera body 100. DO is a serial output terminal for transferring serial data from the strobe device 400 to the camera body 100 in synchronization with the synchronization clock. DI is a serial data input terminal for transferring serial data from the camera body 100 to the strobe device 400 in synchronization with the synchronization clock.

  INT is an integration control output terminal of the photometric integration circuit 436, and AD0 is an A / D conversion input terminal for reading an integrated voltage indicating the light emission amount of the photometry integration circuit 436. DA0 is a D / A output terminal for outputting a comparator voltage of the comparators 431 and 432.

  AD1 is an output terminal of the resistors 404 and 405, Y0 and Y1 are output terminals selected by the data selector 430, TRIG is an output terminal of the trigger generation circuit 413, and YIN is an output terminal of the light emission control circuit 414.

[Operation of First Embodiment (FIGS. 3 to 6)]
Next, the operation of the first embodiment will be described with reference to FIGS.

  3 and 4 show a flowchart of the main routine of the camera body 100 of the present embodiment.

  First, the operation of the system controller 50 will be described with reference to FIGS.

  When the power is turned on, the system controller 50 initializes flags, control variables, and the like (S101), and initializes the image display of the image display unit 28 to the OFF state (S102).

  The system controller 50 determines the setting position of the mode dial switch 60, and if the mode dial switch 60 is set to power OFF (S103), the display of each display unit is changed to the end state. Further, necessary parameters, setting values and setting modes including flags and control variables are recorded in the nonvolatile memory 56, and an unnecessary power source of the camera body 100 including the image display unit 28 is shut off by the power source control unit 80. After performing a predetermined end process (S105), the process returns to S103.

  If the mode dial switch 60 is set to the shooting mode (S103), the process proceeds to S106. If the mode dial switch 60 is set to another mode (S103), the system controller 50 executes processing corresponding to the selected mode (S104), and returns to S103.

  The system controller 50 determines whether there is a problem in the operation of the camera main body 100 with respect to the remaining capacity and the operation status of the power supply unit 86 by the power supply control unit 80 (S106), and if there is a problem, the display unit 54 is used. After performing a predetermined warning display (S108), the process returns to S103.

  If there is no problem in the power supply unit 86 (S106), the system controller 50 determines whether or not the state of the recording medium 120 has a problem in the operation of the camera body 100, particularly in the recording / reproducing operation of the image data with respect to the recording medium 120. (S107). If there is a problem, a predetermined warning is displayed using the display unit 54 (S108), and the process returns to S103.

  If there is no problem in the operation state of the recording medium 120 (S107), the display unit 54 is used to display various setting states of the camera body 100 using images and sounds (S109). If the image display of the image display unit 28 is ON, various setting states of the camera body 100 are displayed using the image display unit 28 as well.

  The system controller 50 determines the setting state of the quick review ON / OFF switch 68 (S110). If the switch is set to ON, a quick review flag is set (S111), and if the switch is set to OFF, the quick review flag is canceled (S112).

  The state of the quick review flag is stored in the internal memory of the system controller 50 or the memory 52.

Subsequently, the system controller 50 determines the setting state of the finder mode setting switch 66 (S113), and sets the EVF flag if the switch is set to ON (S114).
When the EVF mode is not set, that is, when the main mirror 1 is down and the shutter 9 is closed, the mirror control unit 41 is controlled to drive the main mirror 1 up. Further, the shutter control circuit 40 is controlled to open the shutter 9 so that the subject image can be taken into the image pickup device 14 from the lens device 200 into the image pickup device 14 (S114). Further, the image display of the image display unit 28 is set to ON (S115), and the captured image data is set to a through display state for sequentially displaying (S116), and the process proceeds to S119.

  In the through display state, data is sequentially written into the image display memory 24 via the image sensor 14, the A / D converter 16, the image processing circuit 20, and the memory control circuit 22. The EVF function is realized by sequentially displaying data sequentially written in the image display memory 24 on the image display unit 28 via the memory control circuit 22 and the D / A converter 26.

  If the finder mode setting switch 66 is set to OFF (S113), the EVF flag is canceled (S117). When the EVF mode is not set, that is, when the main mirror 1 is up and the shutter 9 is open, the mirror control circuit 41 is controlled to drive the main mirror 1 down. Further, the shutter control circuit 40 is controlled to close the shutter 9 and set it to function as an optical viewfinder, set the image display of the image display unit 28 to the OFF state (S118), and proceed to S119.

  When the image display is OFF, shooting is performed using the optical viewfinder function without using the electronic viewfinder function of the image display unit 28. The state of the EVF flag is stored in the internal memory of the system controller 50 or the memory 52.

  If the shutter switch SW1 is not pressed (S119), the process returns to S103. If the shutter switch SW1 is pressed (S119), the system controller 50 determines the state of the EVF flag stored in the internal memory or the memory 52 (S120). . If the EVF flag is set, the display state of the image display unit 28 is set to the freeze display state (S121), and the process proceeds to S122.

  In the freeze display state, rewriting of image data in the image display memory 24 via the image sensor 14, A / D converter 16, image processing circuit 20, and memory control circuit 22 is prohibited. Further, the image data that has been written last is displayed on the image display unit 28 via the memory control circuit 22 and the D / A converter 26, thereby displaying the frozen image.

  On the other hand, if the EVF flag has been canceled (S120), the process proceeds to S122, where the system controller 50 performs a distance measurement process to focus the lens apparatus 200 on the subject and performs a photometry process to determine an aperture value and a shutter time. (S122).

  Details of the photometry / ranging process S122 will be described later with reference to FIG.

  When the photometry / ranging process is completed in S122, the system controller 50 determines the state of the EVF flag stored in the internal memory or the memory 52 (S123). If the EVF flag is set, the display state of the image display unit 28 is set to the through display state (S124), and the process proceeds to S125. Note that the through display state in S124 is the same operation state as the through state in S116.

  If the shutter switch SW2 is not pressed (S125) and the shutter switch SW1 is also released (S126), the process returns to S103.

  If the shutter switch SW2 is pressed (S125), the system controller 50 determines the state of the EVF flag stored in the internal memory or the memory 52 (S127). If the EVF flag is set, the display state of the image display unit 28 is set to a fixed color display state (S128), and the process proceeds to S129.

  In the fixed color display state, instead of the captured image data written to the image display memory 24 via the memory control circuit 22, the replaced fixed color image data is transferred via the memory control circuit 22 and the D / A converter 26. Are displayed by the image display unit 28. As a result, a fixed color image is displayed on the electronic viewfinder.

  On the other hand, if the EVF flag has been canceled (S127), the system controller 50 executes a photographing process including an exposure process and a development process (S129). In the exposure process, an image photographed in the memory 30 via the image sensor 14, A / D converter 16, image processing circuit 20, memory control circuit 22, or directly from the A / D converter 16 via the memory control circuit 22. Write data. Further, in the development process, the image data written in the memory 30 is read out using the memory control circuit 22 or the image processing circuit 20 as necessary, and various processes are performed.

  Details of the photographing process S129 will be described later with reference to FIG.

  The system controller 50 determines the state of the quick review flag stored in the internal memory or the memory 52 (S130), and displays the quick review if the quick review flag is set (S133). In this case, the image display unit 28 is always displayed as an electronic viewfinder even during shooting, and quick review display immediately after shooting is also performed.

  If the quick review flag is canceled (S130), the system controller 50 reads the captured image data written in the memory 30, and performs various image processing using the memory control circuit 22 and the image processing circuit 20 as necessary. Do. In addition, after performing image compression processing according to the mode set using the compression / decompression circuit 32, recording processing for writing image data to the recording medium 120 is executed (S134).

  Details of the recording process S134 will be described later with reference to FIG.

  If the shutter switch SW2 is pressed after the recording process S134 is completed (S135), the system controller 50 determines the state of the continuous shooting flag stored in the internal memory or the memory 52 (S136). If the continuous shooting flag is set, the process returns to S129 to perform continuous shooting, and the next shooting process is executed. If the continuous shooting flag is not set (S136), the current process is repeated until the shutter switch SW2 is released (S135).

  As described above, when it is set to perform the quick review display immediately after shooting, it is determined whether the shutter switch SW2 is pressed after the recording process (S134) is completed. If the shutter switch SW2 is pressed, the quick review display by the image display unit 28 is continued until the shutter switch SW2 is released, so that the captured image can be checked carefully.

  If the shutter switch SW2 is released after the recording process (S134) is completed (S135), the process proceeds to S138 after a predetermined minimum review time has elapsed (S137). In S135, when the shutter switch SW2 is continuously pressed and the quick review display is continued, and the shutter switch SW2 is subsequently released, the process proceeds to S138 after a predetermined minimum review time has elapsed (S137).

  If the EVF flag is set (S138), the system controller 50 sets the display state of the image display unit 28 to the through display state (S139), and proceeds to S141. In this case, after confirming the captured image by the quick review display on the image display unit 28, it is possible to enter a through display state in which image data captured for the next imaging is sequentially displayed.

  If the EVF flag has been canceled (S138), the image display of the image display unit 28 is set to the OFF state (S140), and the process proceeds to S141. In this case, after confirming the photographed image by the quick review display on the image display unit 28, the function of the image display unit 28 is stopped for power saving, and the image display unit 28 or D / A conversion with large power consumption is stopped. The power consumption of the device 26 and the like can be reduced.

  Next, if the shutter switch SW1 has been pressed (S141), the system controller 50 returns to S125 to prepare for the next shooting.

  If the shutter switch SW1 has been released (S141), the system controller 50 ends a series of shooting operations and returns to S103.

[Photometry / ranging process (Fig. 5)]
Next, the photometry / ranging process in S122 of FIG. 3 will be described.

  FIG. 5 is a flowchart showing details of the photometry / ranging process in S122 of FIG.

  In FIG. 5, when the EVF flag is set (S200), the system controller 50 reads the charge signal from the image sensor 14 and sequentially reads the captured image data into the image processing circuit 20 via the A / D converter 16 (S200). S201). Using the sequentially read image data, the image processing circuit 20 performs predetermined calculations used for TTL (through-the-lens) AE (automatic exposure) processing and AF (autofocus) processing.

  In each process here, a specific part of the total number of captured pixels is extracted according to necessity and extracted and used for calculation. As a result, in each of the TTL method AE, AWB, and AF processes, it is possible to perform an optimal calculation for each of the different modes of the center weight mode, the average mode, and the evaluation mode.

  Using the calculation result in the image processing circuit 20, the system controller 50 performs AE control with a combination of the aperture control circuit 205 and the electronic shutter of the image sensor 14 until it is determined that the exposure (AE) is appropriate (S202) (S202). S203). A diaphragm drive command to the lens device 200 is commanded by well-known serial communication via a communication line 399 between the camera and the lens.

  If it is determined that the exposure (AE) is appropriate by this AE control (S202), the measurement data and the setting parameters are stored in the internal memory or the memory 52 of the system controller 50.

  Using the calculation result in the image processing circuit 20 and the measurement data obtained by the AE control, the system controller 50 determines the color processing parameters by the image processing circuit 20 until it is determined that the white balance (WB) is appropriate (S206). Is adjusted to perform AWB control (S207).

  If it is determined that the white balance is appropriate (S206), the measurement data and setting parameters are stored in the internal memory or the memory 52 of the system controller 50.

  Using the measurement data obtained by the AE control and the AWB control, the system controller 50 instructs the lens device 200 to drive focus through the communication line 399 until ranging (AF) is determined to be in focus (S208). Then, AF control is performed (S209). At this time, the lens control microcomputer 206 controls the focus control circuit 211 according to the focus drive amount or the focus drive speed instructed from the camera, and drives the focusing lens 201 in the optical axis direction. The determination of focus uses so-called contrast AF in which the focusing lens 201 is driven in the optical axis direction to determine the position where the high frequency component of the AF area of the image is the highest as the focus position.

  If it is determined that focusing (AF) is in focus (S208), the measurement data and setting parameters are stored in the internal memory of the system controller 50 or the memory 52, and the photometry / ranging process is terminated.

  Next, when the EVF flag is not set in S200, that is, in the OVF mode, the process proceeds to S210, and the exposure value is calculated according to the photometric result of the photometric sensor 7 and the set ISO sensitivity (S211).

  Next, if the focus shift amount detected by the known TTL phase difference type focus detection unit 8 is within the in-focus range (S212), the photometry / ranging process is terminated. If it is out of focus range (S212), the focusing lens 201 is driven to perform AF control as described in S209 (S213), and the process returns to S212 to perform focus determination.

  When the series of processes is completed, the photometry / ranging process is terminated.

[Shooting process (FIG. 6)]
Next, the photographing process in S129 of FIG. 4 will be described.

  FIG. 6 is a flowchart showing details of the photographing process in S129 of FIG.

In FIG. 6, the system controller 50 determines whether the flash photography mode is set in the EVF mode in which the EVF flag is set (S300, S301), and in the flash photography mode, the subject image is measured by the image sensor 14 before the pre-flash is emitted ( S302). Here, as shown in FIG. 7, the entire screen is divided into a plurality of photometric blocks A (0, 0) to A (7, 5), and the average luminance A (n, n) of each region is calculated. Next, each area is calculated from the brightness level BL at the appropriate light amount with respect to the average brightness A (n, n) of each area, the set shutter speed (accumulation time) TV, aperture value AV, and image sensor sensitivity SV. The luminance BVA (n, n) of the above is calculated by the following equation.
BVA (n, n) = TV + AV + LOG2 (A (n, n) / BL) -SV
Next, the strobe is pre-flashed at a plurality of luminosities or light quantities during a single light emission period with a predetermined light emission time (S303). This pre-flash command is commanded from the system controller 50 on the camera side to the flash control microcomputer 440 through the known serial communication between the flash device 400 and the camera body 100 and via the communication line 499.

  The operation of the flash device 200 during the pre-flash will be described with reference to FIG.

  The strobe control microcomputer 440 boosts the voltage of the battery power supply 401 by the DC / DC converter 402 prior to photographing. Then, when pre-emission with a plurality of light intensities or light amounts is instructed from the system controller 50 on the camera side, a control voltage corresponding to the plurality of first light emission intensities or light amounts is output to DA0.

  Next, Hi and Lo are output to Y1 and Y0, and the input D2 is selected. Since the Xe tube 412 does not emit light, the photocurrent of the light receiving sensor 435 hardly flows, the output of the photometric circuit 434 input to the inverting input terminal of the comparator 431 does not occur, and the output of the comparator 431 is Hi, The control circuit 414 becomes conductive.

  Next, when a trigger signal is output from TRIG, the trigger circuit 413 excites the Xe tube 412 that has generated a high voltage, and light emission is started.

  On the other hand, the strobe control microcomputer 440 instructs the integration photometry circuit 436 to start integration based on the output of INT, and the integration photometry circuit 436 starts integration of the logarithmically compressed photoelectric output of the light receiving sensor 438. In addition, the timer 0 that counts the light emission time instructed by the system controller 50 on the camera side is started, and at the same time, the timer 1 that controls the time for switching the light intensity or the light amount is started.

  When pre-light emission is started, the photocurrent from the flat light emission control light receiving sensor 435 increases, and the output of the photometry circuit 434 increases. When the output of the photometry circuit 434 becomes higher than the comparator voltage of the non-inverting input of the comparator 431, the output of the comparator 431 is inverted to Lo, and the light emission control circuit 414 cuts off the light emission current of the Xe tube 412. As a result, the discharge loop is interrupted. However, since the circulation loop is formed by the diode 409 and the coil 406, the light emission current gradually decreases after the overshoot due to the delay of the circuit is settled.

  As the light emission current decreases, the light intensity or light quantity decreases, so the photocurrent of the light receiving sensor 435 decreases and the output of the photometry circuit 434 also decreases. When the voltage drops below a predetermined comparator voltage level, the output of the comparator 431 is inverted to Hi again, the light emission control circuit 414 is turned on again, a discharge loop of the Xe tube 412 is formed, and the light emission current increases. As a result, the luminous intensity or the amount of light also increases.

  As described above, the comparator 431 repeats increase / decrease in light intensity or light amount at the time of pre-emission in a short cycle with reference to a predetermined comparator voltage set in DA0. Flat light emission is controlled by switching the light amount and repeating light emission.

  When a predetermined light emission time based on the first light intensity or light amount elapses by counting up the timer 1, the voltage corresponding to the second light intensity or light amount is output from DA0, and the first light emission operation is performed in the same manner as described above. The light emission at the second luminous intensity or light quantity is repeated. When a predetermined light emission time elapses due to the above-described timer 0 counting up, the flash control microcomputer 440 sets Y1 and Y0 to Lo and Lo. As a result, the input of the data selector 430 is selected as D0, that is, the Lo level input, the output is forcibly set to the Lo level, and the light emission control circuit 414 cuts off the discharge loop of the Xe tube 412. In this way, pre-emission with a predetermined period and a plurality of luminous intensity or light quantities is repeatedly executed.

  Continuing with the description of FIG. 6, the reflected light of the subject is imaged by the imaging element 14 while the strobe is pre-flashed (S304).

  The charge reading operation of the image sensor in S304 will be described with reference to FIG.

  In FIG. 8, A is an image sensor, and S is a strobe light emission waveform. S1 is the operation of the shutter front curtain, S2 is the operation of the shutter rear curtain, and the vertical axis indicates the vertical position of the shutter opening. That is, when the shutter charge is complete = the shutter is closed, both the front curtain and rear curtain are charged up to the upper position of the shutter opening. In the shutter open state, the rear curtain remains at the upper position of the shutter opening and the shutter front curtain is The image sensor is released and travels to the lower part of the screen, and the image sensor is exposed. When the shutter is closed, the rear curtain is released and travels to the lower part of the screen, and the exposure of the image sensor is completed. C is the reset release timing of the image sensor A described above, and the accumulation of incident light starts simultaneously with the reset release. D is the accumulation end timing, and the period from C to D corresponds to the accumulation time of the image sensor A. In the case of sequential time difference reading, accumulation is performed while shifting the time for each line in order from the top of the image sensor A at time t0, and pixel data is sequentially read from the upper line at time t1. This shift time corresponds to the readout time of one line of the image sensor as described above. As shown by S · P, the light emission waveform of the strobe emits light with the first luminance at the same time as the start of exposure of the uppermost line of the image sensor or at a time slightly before considering the strobe light emission delay. To start. After the accumulation time of one line of the image sensor ends (time t1 in the case of the top line), the accumulation of one line is finished, and image data for one line is read out. Then, after the readout time of one line of the image sensor elapses, the next one line of image data is read sequentially.

  Similarly, when the image data of all lines of the image sensor has been read (time t2), the flash emission is stopped.

  In the meantime, the strobe repeats light emission while switching a plurality of different luminosities or light quantities (two kinds of luminosity levels in FIG. 8) at predetermined intervals as indicated by S · P.

  Therefore, as shown in FIG. 9, the image obtained during this period is synchronized with the readout direction of the image sensor, and a subject image by pre-emission corresponding to a plurality of luminosities or light quantities is obtained.

  Then, as in S302, the entire screen shown in FIG. 9 is divided into a plurality of regions, B (0, 0) to B (7, 5). In each block, the average image luminance level of the first light emission luminance region (high luminance) is B1, and the average image luminance level of the second light emission luminance region (low luminance) is B2. If the luminance level is within the appropriate level range, B2 is adjusted to the image level of B1. That is, after multiplying the gain corresponding to the strobe light emission luminance ratio, a value obtained by averaging B1 and B2 is set as the image luminance level of the region.

  On the other hand, if either image level is too high or too low to exceed the dynamic range of the image sensor, the image level in that area is not used, and the area in the dynamic range is averaged for that block. The brightness level. If both B1 and B2 are saturated, the saturation image brightness level of B2 is used, and if both are low, the image brightness level of B1 is used.

  As described above, the image luminance levels of the entire area B (0, 0) to B (7, 5) are obtained.

Next, as in S302, the image brightness level BVB (m, n) of each region by pre-emission is obtained by the following equation.
BVB (m, n) = TV + AV + LOG2 (B (m, n) / BL) -SV
In S305, by subtracting the image brightness level BVA of each area by the steady light obtained in S302 from the image brightness level BVB of each area obtained by the pre-light emission obtained in S304, the pre-light emission component excluding the steady light component is expressed by the following equation. Ask for.
BVS (m, n) = BVB (m, n) −BVA (m, n)
Further, the pre-light emission component BVS in the area centered on the main subject is obtained by averaging BVS (m, n) in the area centered on the AF distance measurement area.

From this BVS, the main light emission amount BS is obtained from the following equation.
BS = TV-AV-SV-BVS
Next, in preparation for photographing, the shutter 9 in the open state is once closed (S306, t3 in FIG. 8), and then the front curtain of the shutter 9 is opened again (S307, t4 in FIG. 8). 14 exposure is started (S308, t4 in FIG. 8).

  Next, in the flash photography mode (S309), the main flash amount obtained in S306 is commanded to the flash device 400, and the flash device 400 performs main flash with the commanded flash amount (S310, t5 in FIG. 8).

  After the predetermined exposure time, the rear curtain of the shutter 9 is closed (S311 corresponding to t6 in FIG. 8), and the accumulation of the image sensor 14 is terminated. Further, the actual captured images are sequentially read from the pixels on the image sensor 14 (S312, accumulation ends at the timing G in FIG. 8 and images are read line by line at the timing H).

  In this example, as described in S306, S307, and S311, the exposure control in the case of the actual photographing is intentionally performed by the mechanical shutter 9 instead of the electronic shutter (electronic shutter by time difference sequential reading). This is to prevent the deterioration of image quality due to high brightness smear.

  On the other hand, if the EVF mode is not set in S300, the process proceeds to S321. If the flash photography mode is selected (S321), the subject image is measured by the photometric sensor 7 before the pre-flash. That is, the subject image is formed on the focus plate 2 through the lens device 200, and the image is formed on the photometric sensor 7 through the photometric lens 6, and this subject image is photoelectrically converted by the photometric sensor 7 and integrated for a predetermined time. Metering of the subject in the steady light is performed (S322).

  Next, as in S304, the strobe is pre-flashed with a predetermined light emission amount (S323).

  Next, the reflected light from the subject due to the pre-flash of the strobe is measured by the photometric sensor 7 (S324).

  Next, by subtracting the photometry data at the time of stationary light obtained at S322 from the photometry data at the time of pre-light emission obtained at S324, only the subject reflected light component due to the pre-light emission is extracted. Then, the main light emission amount is obtained from the difference between the subject reflected light component and the photometric data of the photometric sensor 7 based on the subject reflected light at the appropriate amount of light according to the ISO sensitivity of the image sensor 14 stored in advance in the system controller 50 ( S325). As described above, since the output of the photometric sensor 7 is logarithmically compressed, the calculation can be performed by addition / subtraction.

  Next, when preparation for photographing is completed, the system controller 50 raises the main mirror 1 and the sub mirror 3 and retracts them from the optical axis. Further, the system controller 50 instructs the lens apparatus 200 to narrow down to a predetermined aperture value via the communication line 399 between the camera and the lens, and the lens control microcomputer 206 controls the aperture control circuit 205 to set the aperture 204. The aperture value is narrowed down to a predetermined aperture value (S326).

  Next, the system controller 50 controls the shutter control unit 40, opens the shutter 9 (S327), and starts exposure of the image sensor 14 (S328).

  Next, in the flash photography mode (S329), the main flash amount obtained in S325 is commanded to the flash device 400, and the flash device 400 performs main flash with the commanded flash amount (S330). After the predetermined exposure time, the shutter 9 is closed (S331), the accumulation of the image sensor 14 is completed, and the exposure is completed (S332). At the same time, the mirror retracted from the optical axis in S326 is returned to the original position. In the same manner as S326, the aperture is driven to open.

  Next, the charge signal is read out from the image sensor 14, and the memory is sent via the A / D converter 16, the image processing circuit 20, the memory control circuit 22, or directly from the A / D converter 16 via the memory control circuit 22. Data of the photographed image is written in 30 (S340).

  Next, the system controller 50 reads the image data written in the memory 30 using the memory control circuit 22 and, if necessary, the image processing circuit 20, and performs color processing (S341). Thereafter, the processed image data is written in the memory 30, and the display image data is transferred to the image display memory 24 via the memory control circuit 22 (S342).

  When the series of processing is completed, the photographing process is terminated.

[Recording process (FIG. 10)]
Next, the recording process in S134 of FIG. 3 will be described.

  FIG. 10 is a flowchart showing details of the recording process in S134 of FIG.

  The system controller 50 reads the image data written in the memory 30 and performs image compression processing according to the set mode by the compression / decompression circuit 32 (S401). Thereafter, the compressed image data is written to the recording medium 120 such as a memory card or a compact strobe card via the interface 90 or 124 and the connector 92 or 126 (S402).

  When the writing to the recording medium is completed, the recording process is terminated.

  According to the present embodiment, the image sensor A is configured to be able to sequentially read out the time difference, and the reset of the photodiode is canceled according to the reading direction of the image data (C in FIG. 8), and after the predetermined exposure time, the image is read out. In this configuration, transfer to the memory is sequentially performed for each line (E in FIG. 8).

  Here, the strobe pre-flash is started simultaneously with the start of exposure by the image sensor A (S303 in FIG. 6, t0 in FIG. 8), and the light emission intensity of the strobe for each predetermined readout area or until the sequential reading is completed. Pre-light emission is performed by changing the light emission amount (SP in FIG. 8). Then, the main light emission amount is calculated based on the image captured during pre-flash (S304 in FIG. 6) (S305 in FIG. 6), and flash photography is performed based on the calculated light emission amount.

  Thus, since an image with a wide dynamic range can be obtained by one imaging at the time of pre-emission, an appropriate amount of main light emission is required, and favorable flash photography can be performed in a wide imaging distance range.

[Other Embodiments]
The present invention includes a case where the computer program for realizing the functions of the above-described embodiments is achieved by supplying the system or apparatus directly or remotely. In that case, a computer such as a system reads and executes the computer program.

  Therefore, in order to realize the functional processing of the present invention with a computer, the computer program itself installed in the computer also implements the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Examples of the recording medium (storage medium) for supplying the program include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. In addition, there are MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a client computer browser can be used to connect to a homepage on the Internet, and the computer program itself of the present invention can be downloaded from the homepage. It can also be supplied by downloading a compressed file including an automatic installation function to a recording medium such as a hard disk. It can also be realized by dividing the computer program constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and a user who satisfies predetermined conditions downloads key information for decryption from a homepage via the Internet. You can also. In this case, the downloaded key information is used to execute the encrypted program and install it on the computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS or the like operating on the computer based on the instruction of the program may be a part of the actual processing. Alternatively, it can be realized by performing all of them.

  Furthermore, after the program read from the recording medium is written in the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer, the CPU of the board or the like performs a part of the actual processing. Alternatively, it can be realized by performing all of them.

It is a block diagram of an imaging device of an embodiment concerning the present invention. It is a block diagram which shows the internal structure of the flash device of this embodiment. It is a flowchart of the main routine of the camera of this embodiment. It is a flowchart of the main routine of the camera of this embodiment. 4 is a flowchart showing details of photometry / ranging processing in S122 of FIG. 3; 5 is a flowchart showing details of a photographing process in S129 of FIG. It is a figure explaining the brightness | luminance calculation area | region of the captured image based on the 1st Embodiment of this invention. It is a figure explaining the timing of charge reading of the image sensor and strobe light emission in S304. It is a figure explaining the luminance calculation area | region of the captured image at the time of pre light emission based on the 1st Embodiment of this invention. It is a flowchart which shows the detail of the recording process in S134 of FIG. It is a figure which shows the structure of the interline type CCD of a prior art example. It is a timing chart which shows the flash photographing process in CCD. It is a figure which shows the circuit structure of a CMOS sensor. It is a figure explaining the timing of charge reading by the conventional image sensor, and strobe light emission.

Explanation of symbols

9 Shutter 14: Image sensor 16: A / D converter 18: Timing generation circuit 20: Image processing circuit 22: Memory control circuit 24: Image display memory 26: D / A converter 28: Image display unit 30: Memory 32: Compression / decompression circuit 40: Shutter control unit 41: Mirror control unit 50: System controller 52: Memory 54: Display unit 56: Non-volatile memory 60: Mode dial switch 62: Shutter switch SW1
64: Shutter switch SW2
66: Finder mode setting switch 68: Quick review ON / OFF switch 70: Operation unit 72: Communication unit 73: Connector (antenna)
80: power supply control unit 82, 84: connector 86: power supply unit 90: interface 92: connector 98: recording medium attachment / detachment detection unit 100: camera body 120: recording medium 122: recording unit 124: interface 126: connector 200: lens device 400 : Strobe device

Claims (10)

An imaging device that captures an image by converting an optical image of a subject into an electrical signal,
An image sensor for sequentially storing and reading out charges while shifting the time for each line;
A flash device that irradiates the subject with light during shooting,
A light emission control means for starting the preliminary light emission by the flash device at the start of charge accumulation by the imaging device and repeatedly emitting the flash device while changing the preliminary light emission level until the reading of the charge is completed;
Calculating means for calculating a main light emission level by the flash device based on an image obtained by the preliminary light emission;
An imaging apparatus comprising: an imaging control unit configured to capture an image by causing the flash device to emit light at the calculated main light emission level.   The imaging apparatus according to claim 1, wherein the light emission control unit repeatedly performs the preliminary light emission while switching the preliminary light emission level at regular intervals.   The imaging device according to claim 1, wherein the imaging device is a CMOS sensor, and the flash device is a strobe device that can be attached to and detached from the imaging device.   The calculating means calculates the main light emission level using a luminance value of an image obtained in a state where the flash device is not caused to emit light before the preliminary light emission and a luminance value of an image obtained by the preliminary light emission. The imaging apparatus according to any one of claims 1 to 3, wherein An image sensor for sequentially storing and reading out charges while shifting the time for each line;
A flash device that emits light to a subject at the time of shooting, and a method for controlling an imaging device that takes an image by converting an optical image of the subject into an electrical signal,
A preliminary light emission step of starting the preliminary light emission by the flash device at the start of charge accumulation by the imaging device and repeatedly emitting the flash device while changing the preliminary light emission level until the reading of the charge is completed;
A calculation step of calculating a main light emission level by the flash device based on an image obtained by the preliminary light emission;
And a photographing step of capturing an image by causing the flash device to emit light at the calculated main light emission level.   6. The control method according to claim 5, wherein, in the preliminary light emission step, the preliminary light emission is repeatedly performed while switching the preliminary light emission level at regular intervals.   The control method according to claim 5, wherein the image pickup device is a CMOS sensor, and the flash device is a strobe device that can be attached to and detached from the image pickup device.   In the calculating step, the main light emission level is calculated by using a luminance value of an image obtained in a state where the flash device is not caused to emit light before the preliminary light emission and a luminance value of the image obtained by the preliminary light emission. The control method according to claim 5, wherein:   The program for making the computer of an imaging device perform the control method of any one of Claims 5 thru | or 8.   A computer-readable storage medium storing the program according to claim 9.

Images