JP2005156793A - Camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously perform speed light photography without prohibiting a camera operation while preventing heating of a stroboscopic light emitting part and its peripheral part by continuous light emission of a strobe. <P>SOLUTION: The camera system having the stroboscopic light emitting part which performs flash light emission, comprises a measurement means (S101) for measuring energy to be obtained by the flash light emission of the stroboscopic light emission part and a control means (S102→S103→S104) for reducing the flash light emission quantity at the time of continuously performed speed light photography when a measurement result by the measurement means becomes larger than a predetermined value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a camera system including a combination of a strobe device and a camera.

In recent years, strobe devices attached to cameras are required to have higher performance as the performance of the cameras increases, and at the same time, higher guide numbers are also required. In addition, in a camera with a built-in strobe, the strobe light emitting unit is also miniaturized and the airtightness is increased with the miniaturization of the camera. For this reason, when the flash shooting is performed under the full flash emission or near the full flash, or when the flash is continuously emitted, the flash emission section and the surrounding area may generate heat, which may cause discomfort to the user. In view of this point, there has been proposed a camera (for example, Patent Document 1) that counts the number of flashes emitted by a counter and stops the flash emission when the number of flashes reaches a predetermined number.
JP-A-11-212151

  However, in the case of a configuration in which the number of flashes is counted and the flash emission is stopped when the predetermined number of times is reached as in the proposed camera, the photographer cannot take a picture at a desired timing and misses a photo opportunity. Had.

  In order to solve the above-described problems, the present invention provides a camera system having a flash light emitting unit that emits flash light, a measuring unit that measures energy obtained by the flash light emission of the strobe light emitting unit, and a measurement result by the measuring unit. When it becomes larger than the predetermined value, the camera system has a control means for reducing the amount of flash emission during continuous flash photography.

  In the above configuration, when the flash photography is continuously performed, the flash light emitting unit and its peripheral part are heated and give the user an unpleasant feeling, so the energy obtained by flash emission of the flash light emitting unit is measured, For example, measure the temperature of the flash unit, or measure the integrated amount of light emitted from the flash unit, and if this measurement result exceeds a predetermined value, the flash emission during continuous flash photography The amount is reduced so that the strobe light emitting part and its peripheral part are not heated to such an extent that they feel uncomfortable. In addition, when control is performed to reduce the amount of flash emission, the exposure condition is changed at the same time so that proper exposure can be obtained.

  The “measurement of the temperature of the strobe light emitting part” includes the measurement of the temperature around the strobe light emitting part. The “continuous flash photography” is not limited to the flash photography in the continuous shooting mode. Even in the single-shot mode, the case where the next flash photography is performed before the temperature of the flash light emitting section heated by the flash photography and its peripheral part, for example, does not become lower than the predetermined value is included.

  The present invention is also directed to a camera system comprising a strobe light emitting unit that emits flash light, and an irradiation angle varying unit that changes an irradiation angle of the strobe light emitting unit according to a focal length of a photographing lens. Measuring means for measuring energy obtained by light emission, and when the measurement result by the measuring means is larger than a predetermined value, the strobe light emitting unit during continuous flash photography by the irradiation angle variable means And a control means for changing the irradiation angle to the telephoto side from the focal length of the photographing lens at that time.

  In the above configuration, when continuous flash photography is performed, the strobe light emitting unit and its surroundings are heated to cause discomfort to the user, so the measurement result of energy obtained by flash emission of the strobe light emitting unit Is larger than the predetermined value, the flash emission amount is equivalently reduced by changing the illumination angle of the flash unit to the telephoto side from the focal length of the photographing lens at that time, and the flash unit and its surroundings. It is set as the structure which does not heat so that a part may give discomfort. Further, when control is performed to change the irradiation angle to the telephoto side, the exposure condition is changed at the same time so that proper exposure can be obtained.

  According to the present invention, it is possible to provide a camera system that can continuously perform flash photography without prohibiting the operation of the camera while preventing heating of the flash light emitting part and its peripheral part due to continuous light emission of the flash. .

  As shown in Examples 1 to 3 below.

  FIG. 1 is a configuration diagram showing the main part of the camera system according to Embodiment 1 of the present invention. As shown in FIG. 1, the camera system of the first embodiment includes a camera including a camera body 1 and a photographing lens 2 having a plurality of lenses, and an external flash unit (= external flash device) 31. The taking lens 2 and the flash unit 31 are detachably attached to the camera body 1.

  The taking lens 2 includes a first group lens 3, a second group lens 4, and a third group lens 5. The first group lens 3 is an AF (autofocus) lens, and the focus position of the photographing screen can be adjusted by moving the first group lens 3 in the optical axis direction. The second group lens 4 is a lens for zooming. By moving the second group lens 4 in the optical axis direction, zooming of the shooting screen is performed, and the focal length of the shooting lens is changed. The third group lens 5 is a fixed lens. Note that although the photographing lens 2 is shown as three lenses for convenience in the first embodiment, it is well known that it is actually composed of a larger number of lenses.

  A main mirror 6 is a half mirror and is rotatably supported by a hinge shaft (not shown). In the observation state, the main mirror 6 is obliquely provided in the photographing optical path, and the light beam transmitted through the photographing lens 2 is transmitted to the finder and sub mirror. And is removed when shooting. Reference numeral 7 denotes a sub mirror, which is rotatably supported by a main mirror 6 by a hinge shaft (not shown), and reflects the light beam transmitted through the main mirror 6 toward the lower side of the camera body 1 in an observation state. In the shooting state, it is retracted from the shooting optical path in conjunction with the main mirror 6. Reference numeral 8 denotes a shutter. An optical filter 9 in which an optical low-pass filter and an infrared cut filter are integrated is disposed behind the shutter 8, and an imaging element 10 including a CCD or the like for recording a photographed image is disposed behind the optical filter 9. Is arranged.

  11 is a well-known phase difference type focus detection composed of an area sensor 11f including a field lens 11a, reflection mirrors 11b and 11c, a secondary imaging lens 11e, a diaphragm 11d, a CCD, and the like disposed in the vicinity of the imaging surface. It is an apparatus, and is configured so that focus detection is possible in three areas of an object scene described later. Reference numeral 12 denotes a focusing plate disposed on the planned imaging plane of the photographic lens 2. Reference numeral 13 denotes a condenser lens for effectively guiding the light beam from the photographing lens 2 to the eyepiece lens 16. 14 is a field mask for forming a finder field area, and 15 is a penta roof prism for changing the finder optical path. Reference numeral 16 denotes an eyepiece arranged behind the penta roof prism 15, and the light flux of the subject image formed on the focus plate 12 reaches the photographer's eyeball 17 and is observed.

  Reference numerals 18 and 19 denote an imaging lens and a multi-divided photometric sensor for measuring the luminance of the object in the observation screen. The imaging lens 18 is connected to the focusing screen 12 and the multi-divided photometric sensor 19 via the reflected light path in the penta roof prism 15. Are positioned in a conjugate imaging relationship. Reference numeral 21 denotes an internal liquid crystal display composed of a TN (Twisted Nematic) liquid crystal display for displaying photographing information outside the viewfinder field. The internal liquid crystal display 21 is illuminated by an illumination LED (light emitting diode) 20. Is transmitted through the triangular prism 22 into the finder, and the photographing information is displayed outside the finder field. As a result, the photographer can know the photographing information.

  Reference numeral 23 denotes a diaphragm provided in the photographing lens 2, reference numeral 24 denotes a diaphragm driving device including a diaphragm driving circuit 111, which will be described later, reference numeral 25 denotes a lens driving motor, and reference numeral 26 denotes a lens driving member including a driving gear. Reference numeral 27 denotes a photocoupler. When the rotation of the pulse plate 28 interlocked with the lens driving member 26 is detected and transmitted to the AF driving circuit 110, the AF driving circuit 110 uses this information and the lens driving amount information from the camera side. Based on this, the lens driving motor 25 is driven by a predetermined amount, and the first lens group 3 is moved in the optical axis direction to automatically move to the in-focus position. A mount contact 29 serves as an interface between the camera body 1 and the taking lens 2, and various information communication is performed between the camera and the lens through the mount contact 29. Reference numeral 30 denotes a monitor display made of TFT (Thin Film Transistor) liquid crystal for displaying image data obtained by the image sensor 10.

  Reference numeral 31 denotes an external flash unit which is attached to the camera body 1 and performs light emission control in accordance with a signal from the camera. Reference numeral 32 denotes a stroboscopic light emitting unit, which is emitted from a xenon tube 32a for exchanging current energy to luminescent energy, a reflector 32b for efficiently condensing luminescent energy emitted from the xenon tube 32a toward a subject, and a xenon tube 32a. A monitor sensor 32c (PD (Photo Diode) 2) for monitoring light and a temperature sensor 32d for detecting the temperature in the strobe light emitting unit 32 are configured. The strobe unit 31 can emit flat light by limiting the light emission current of the xenon tube 32a by the output of the monitor sensor 32c. Reference numeral 33 denotes a Fresnel lens, which plays a role of efficiently condensing light emission energy emitted from the xenon tube 32a toward the subject. Reference numeral 34 denotes a glass fiber as light transmission means, which guides light emitted from the xenon tube 32a to a monitor sensor 35 (PD1) which is a monitor sensor. The monitor sensor 35 measures the light quantity of preliminary light emission and main light emission of the strobe directly.

  Reference numeral 36 denotes a strobe light emitting unit driving motor, and 37 a strobe light emitting unit driving member composed of a drive gear and the like. The strobe light emitting part 32 is led. Reference numeral 38 denotes a known accessory shoe contact that serves as an interface between the camera body 1 and the flash unit 31.

  FIG. 2 is a diagram showing how the photometry area is divided on the photographing screen and the display contents of the internal liquid crystal display 21. The function of the multi-division photometry sensor 19 and information in the viewfinder will be described in detail.

  Reference numeral 50 denotes the entire photographing screen. Reference numeral 51 denotes an area to be measured on the photographing screen of the multi-division photometric sensor 19, and the photographing screen is divided into six areas like E0, E1, E2, E3, E4, and E5. In this way, the multi-division photometric sensor 19 associated with the imaging screen in a conjugate manner can divide the imaging screen and measure and output each luminance value. P0, P1, and P2 indicate focus detection points for focus detection, and the focus detection device 11 detects the focus states at three points in the screen.

  Next, the display contents on the internal liquid crystal display 21 will be described. 21a is an AE lock mark indicating that the exposure value is locked, 21b is a strobe charging completion mark indicating that the strobe charging is completed, 21c is a strobe flashing automatic reduction mark described later, 21d is a shutter-second display segment, and 21e is An aperture display segment, 21f is an exposure correction amount display segment, and 21g is an in-focus mark indicating the in-focus state of the taking lens 2.

  FIG. 3 is a block diagram showing a circuit configuration of the camera system of FIG. In FIG. 1, an MPU 100 is a processing circuit such as a microcomputer having an EEPROM 100a, an A / D converter 100b, and the like, and performs an internal operation based on a clock generated by an oscillator 101. Connected to the MPU 100 are a focus detection circuit 102, a photometry circuit 103, a shutter drive circuit 104, a motor control circuit 105, a liquid crystal display drive circuit 106, a signal input circuit 107, and a video signal processing circuit 108. Further, a signal is transmitted to the in-lens control circuit 109 disposed in the photographing lens 2 via the mount contact 29 shown in FIG. 1, and the strobe unit 31 is connected to the accessory shoe contact 38 shown in FIG. The signal is transmitted via the.

  The focus detection circuit 102 performs accumulation control and readout control of the area sensor 11f in accordance with the signal of the MPU 100 and outputs pixel information to the MPU 100. The MPU 100 performs A / D conversion on the pixel information and performs focus detection information by a known phase difference detection method. Is calculated. The MPU 100 adjusts the focus of the lens by transmitting a signal to the in-lens control circuit 109 based on the focus detection information. The photometry circuit 103 outputs to the MPU 100 the output from the multi-division photometry sensor 19 composed of a plurality of photodiodes corresponding to each of the six areas in the screen, as a luminance signal of each area in the screen. The photometry circuit 103 outputs a luminance signal in both a steady state in which strobe light is not preliminarily emitted toward the subject and a preliminary emission state in which preflash is emitted, and the MPU 100 performs A / D conversion on the luminance signal and performs shooting. The aperture value for adjusting the exposure, the shutter speed, and the flash emission amount at the time of exposure are calculated.

  The shutter drive circuit 104 controls the image sensor 10 by controlling a magnet (MG-1) (not shown) for running the shutter front curtain and a magnet (MG-2) (not shown) for running the shutter rear curtain. Accumulate a predetermined amount of light. The motor control circuit 105 controls the motor M in accordance with a signal from the MPU 100 in order to up / down the main mirror 6 and charge the shutter 8. The liquid crystal display driving circuit 106 converts into a form suitable for display output in accordance with a display content command from the MPU 100, and drives the internal liquid crystal display 21, the monitor display 30, and an external liquid crystal display 60, which will be described later, to display contents on each. Is displayed.

  The signal input circuit 107 transmits signals from the release switch 150, the strobe mode switch 151, the shooting mode switch 152, and the ISO sensitivity setting switch 153 to the MPU 100. The release switch 150 includes a two-stage switch, that is, a switch SW1 that is half-pressed and a switch SW2 that is fully pressed. Camera photometry and distance measurement are started when the switch SW1 is turned on, and camera exposure is performed when the switch SW2 is turned on. Operation starts. The strobe mode switch 151 is for selecting a strobe emission amount automatic reduction mode for preventing overheating of the strobe light emitting unit 32 and its peripheral part during strobe photography. The details of the strobe emission automatic reduction mode will be described later. The shooting mode switch 152 is used to select a camera exposure control method during shooting. The ISO sensitivity setting switch 153 is for setting an ISO value obtained by quantifying the sensitivity to light at the time of photographing.

  The video signal processing circuit 108 photoelectrically converts the subject image from the photographic lens 2 by the imaging device 10 constituted by a CCD (charge coupled device) or the like and takes it out as an electrical signal, and a clamp / CDS (correlated double sampling) circuit 113. And AGC (automatic gain adjusting device) 114 performs basic analog processing before A / D conversion, receives a signal converted into a digital signal by A / D converter 115, and filters the digitized image data. Processing, color conversion processing, and gamma / knee processing are performed and output to the memory controller 116. Further, the video signal processing circuit 108 includes a D / A converter 108a, and converts the video signal input from the image sensor 10 and the image data input reversely from the memory controller 116 into an analog signal. It is also possible to output to an EVF (electric viewfinder) monitor (not shown). Also, it is possible to store image data in the buffer memory 117 through the memory controller 116 without doing anything in accordance with an instruction from the MPU 100. The video signal processing circuit 108 also has a function of performing compression processing such as JPEG. In the case of continuous shooting, image data is temporarily stored in the buffer memory 117, and image processing and compression processing by the video signal processing circuit 108, which takes a long time, are processed by the unprocessed image data stored in the buffer memory 117 through the memory controller 116. By reading and performing, the continuous shooting speed is increased without waiting for these processes. Therefore, the number of continuous shots greatly depends on the size of the buffer memory 117.

  In the memory controller 116, unprocessed digital image data input from the video signal processing circuit 108 is stored in the buffer memory 117, and the processed digital image is stored in the memory 118, or conversely from the buffer memory 117 or the memory 118. Image data is output to the video signal processing circuit 108. In addition, the memory controller 116 can store the video transmitted from the external interface 119 in the memory 118 and can output the image stored in the memory 118 from the external interface 119. The memory 118 may be freely removable from the imaging device main body.

  The in-lens control circuit 109 has storage means such as a ROM in which various kinds of specific information regarding the photographing lens such as the open F number, focal length, and focus correction amount are stored in advance, and communicates with the MPU 100 via the mount contact 29. Then, the AF drive circuit 110 and the aperture drive circuit 111 are controlled to control the position and aperture of the first lens group 3. Further, the position information of the first group lens 3 is obtained by counting the number of pulses of the pulse plate 28 described above, and the absolute distance information of the subject is transmitted to the MPU 100. The power supply unit 120 supplies power necessary for the MPU 100 and other ICs (integrated circuits) and drive systems. The finder unit 121 includes the focus plate 12, the condenser lens 13, the penta roof prism 15, the eyepiece lens 16, and the like.

  FIG. 4 is a block diagram showing a circuit configuration in the strobe unit 31 described above.

  Reference numeral 200 denotes a strobe control circuit that emits strobe light toward the subject in accordance with a signal from the MPU 100. The strobe control circuit 200 can control the light emission amount, the peak value of the flat light emission, the light emission time, and the like. Reference numeral 201 denotes a DC / DC converter as a booster circuit, which can boost the battery voltage in accordance with an instruction from the strobe control circuit 200 and store about 300 V in the main capacitor C1. R1 and R2 are voltage dividing resistors provided for the strobe control circuit 200 to monitor the voltage of the main capacitor C1. The strobe control circuit 200 indirectly monitors the voltage of the main capacitor C1 by performing A / D conversion on the divided voltage by the A / D converter 202, and the DC / DC converter 201 is deactivated to increase the voltage. The current charging voltage can be monitored and transmitted to the MPU 100. A trigger circuit 203 outputs a trigger via the strobe control circuit 200 according to an instruction from the MPU 100 during exposure, generates a high voltage in the xenon tube 32a, and transfers the charge energy stored in the main capacitor C1 to the xenon tube 32a. The electric flash starts to emit light. 204 is a light emission stop circuit, which is ON at the time of the trigger output described above, but light emission is started and turned OFF by the output of the comparator 205 or 206 as a comparison means and the light emission stop signal from the strobe control circuit 200, The light emission of the xenon tube 32a is stopped.

  Next, the operation of the flash unit 31 in the above configuration will be described in detail.

≪Flat emission≫
The strobe control circuit 200 sets a predetermined value in the D / A converter (digital / analog converter) 207. At this time, since the xenon tube 32a has not yet started to emit light, the photocurrent of the monitor sensor 35 is small, and the output of the monitor circuit 209 input to the inverting input terminal of the comparator 206 is low. Therefore, the comparator 206 outputs HI (which means high level) to the light emission stop circuit 204. Thereafter, when the strobe control circuit 200 outputs a trigger signal via the trigger circuit 203, the xenon tube 32a starts to emit light, and the peak value of the emission immediately rises to increase the photocurrent of the monitor sensor 35. The output of 209 rises and the output of the comparator 206 becomes LOW (meaning low level). When the output of the comparator 206 becomes LOW, the light emission stop circuit 204 is activated and the discharge loop of the xenon tube 32a is cut off, but a recirculation loop is formed by the diode D1 and the coil L1, and the peak value is gradually reduced without instantaneously dropping. Falling. When the peak value falls, the photocurrent of the monitor sensor 35 decreases, so the output of the comparator 206 turns to HI again, a discharge loop of the xenon tube 32a is formed, and the peak value rises. Thus, the output of the comparator 206 repeatedly increases and decreases the peak value in a short cycle, and as a result, flat light emission control is performed in which light emission is continued at a substantially constant peak value.

  In order to end the flat light emission, the strobe control circuit 200 directly outputs a signal to the light emission stop circuit 204. In addition, the peak value of the flat emission changes the operating point of the photocurrent of the monitor sensor 35 by changing the voltage input to the non-inverting input terminal of the comparator 206 according to the digital value applied to the D / A converter 207. It can be controlled to a desired value. The light emission time can also be controlled to a desired time.

≪Preliminary light emission and integration≫
In the preliminary light emission, the above-described flat light emission is performed at a predetermined peak value for a predetermined time. At this time, the monitor sensor 32c measures the light emission luminance of the xenon tube 32a, and the strobe control circuit 200 instructs the integration circuit 211 to start integration, and in response to this, the integration circuit 211 uses the output from the monitor circuit 210 as a spare. Start integrating light emission. Note that the light emission stop circuit 204 is supplied with the output of the comparator 205 in which the output of the integration circuit 211 is input to the inverting input terminal, but this is set so as to be ignored by the signal from the strobe control circuit 200. Therefore, the above-described flat light emission control is not hindered.

  When the preliminary light emission for a predetermined time is completed, the strobe control circuit 200 can A / D convert the output of the integration circuit 211 integrating the preliminary light emission by the A / D converter 202 and read the integrated value as a digital value.

≪Main flash control≫
The MPU 100 obtains an appropriate integral value of the main light emission amount from the integral value of the preliminary light emission described above, the subject reflected light luminance value from the multi-division photometry sensor 19 at the time of the preliminary light emission, and the like via the terminal 208 and the strobe control circuit 200. The appropriate integral value is set in the D / A converter 207. The integrating circuit 211 is brought into an initial state, and the trigger circuit 203 starts light emission. The light emission luminance of the xenon tube 32a measured by the monitor sensor 32c is integrated by the integration circuit 211. When the integral output reaches the set proper integration value, the output of the comparator 205 is switched from HI to LOW, and the light emission stop circuit 204 is reached. Stops the light emission. At this time, the output of the comparator 206 is set so as to be ignored by the signal from the strobe control circuit 200. In this way, the light emission amount of the main light emission can be controlled to an appropriate light emission amount obtained by calculation.

  Next, the operation of the camera system configured as described above will be described with reference to FIGS.

  First, the main operation of the camera system will be described with reference to the flowchart of FIG. When the operation of the camera is started, various memory contents and program flags in the MPU 100 are reset (initially set) in step S1 of FIG. In the next step S2, the state of the switch SW1 included in the release switch 150 is detected. The operation of step S2 is repeated until the switch SW1 is detected ON, and when the switch SW1 is turned ON, the process proceeds to step S3.

  In step S3, the signal input circuit 107 detects the state of each switch for various camera controls, such as the strobe mode switch 151, the ISO sensitivity setting switch 153, and the shooting mode switch 152 which is a method for determining the shutter value and the aperture value. The signal is transmitted to the MPU 100. In addition, various unique information regarding the photographing lens 2 such as an open F number and a focal length of the photographing lens 2 mounted via the mount contact 29 is transmitted to the MPU 100 as a signal. The strobe control circuit 200 in the strobe unit 31 receives focal length information of the photographing lens 2 via the accessory shoe contact 38 and controls the movement of the strobe light emitting unit 32 to a position corresponding to the focal length of the photographing lens 2. Do. The flash mode includes a normal flash mode based on the above-described flash control and a flash emission amount automatic reduction mode for preventing overheating of the flash unit 32 and its surroundings during flash photography, which will be described later. Among the automatic light emission amount reduction modes, there are an exposure shift mode in which the shutter speed or aperture value or both are shifted, and an ISO shift mode in which the ISO is shifted, which can be selected by the photographer. In the first embodiment, the following description will be given on the assumption that the automatic flash emission amount reduction mode is selected.

  When the strobe light emission amount automatic reduction mode is selected by the strobe mode switch 152, it is displayed on the internal liquid crystal display 21 and the external liquid crystal display 60 in order to let the photographer know that the mode is selected. Here, the display content of the internal liquid crystal display 21 and the display content of the external liquid crystal display 60 will be described with reference to FIGS.

  FIG. 6 shows the display contents of the internal liquid crystal display 21. FIG. 6A shows the display contents when the strobe mode is the normal light emission mode. The strobe charging completion mark 21b is lit based on the charging voltage information of the main capacitor C1 of the strobe unit 31, and the strobe shooting is possible. FIG. 6B shows display contents when the strobe light emission automatic reduction mode is selected, and the strobe light emission automatic reduction mark 21c is lit to inform the photographer that the current strobe light emission automatic reduction mode is in effect. . FIG. 6C shows the display contents when the temperature or integrated light emission amount in a flash unit 32, which will be described later, is greater than or equal to a predetermined value when the strobe light emission automatic reduction mode is selected, and the strobe light emission amount automatic reduction mark 21c blinks. By doing so, the photographer is informed that the automatic flash emission reduction is operating.

  FIG. 7 shows the display content of the external liquid crystal display 60. In the figure, 61a is a shutter speed segment for displaying the shutter speed and ISO sensitivity, 61b is an aperture segment for displaying the aperture value, and 61c is a display for displaying the photographing mode and the ISO display state. A segment 61d is a counter segment for displaying the number of shootable frames, and 61e is a drive mode segment for displaying a shooting drive mode, which displays a state of continuous shooting, single shooting or self shooting. Reference numeral 61f denotes a battery remaining amount display segment, 61g denotes an exposure correction amount display segment, 61h denotes a strobe charge completion mark segment, and 61i denotes a strobe light emission amount automatic reduction mark segment for indicating that the strobe light emission amount automatic reduction mode is in effect. This strobe light emission amount automatic reduction mark segment 61i, like the internal liquid crystal display 21, blinks when the temperature in the strobe light emitting unit 32 or the integrated light emission amount is equal to or higher than a predetermined value, and the strobe light emission amount automatic reduction is activated. To the photographer.

  Returning to the flow of FIG. 5, after various switch detection is performed in step S3, the process proceeds to step S4, and a focus detection operation is performed. As described above, this is based on a known phase difference detection method by the focus detection circuit 102. Based on this focus detection result, the MPU 100 controls the in-lens control circuit 109 to adjust the focus of the first group lens 3. As described with reference to FIG. 2, there are three points for focus detection on the screen, but it is possible to use a method in which the photographer can arbitrarily set which point of the subject to focus on, and prioritize near points. A well-known automatic selection algorithm method based on the basic concept may be used. In the next step S5, the MPU 100 obtains the subject luminance values of the six areas on the screen from the photometry circuit 103, determines the exposure amount by a known algorithm from the subject luminance values of the six areas, and sets the photographing mode set. Accordingly, the shutter speed value and the aperture value are determined. In the subsequent step S6, a sequence of the strobe emission amount automatic reduction mode is executed. It is determined whether or not the flash light emission amount is automatically reduced by this sequence, and if necessary, the light emission amount is corrected and the exposure value is changed. Details of this sequence will be described later.

  In the next step S7, it is determined whether or not the switch SW2 included in the release switch 150 is ON. If it is OFF, the process returns to step S2, and the operations from steps S2 to S6 are repeated. Thereafter, when the switch SW2 is turned on, the following operations after step S8 are executed.

  In step S8, the MPU 100 transmits the information from the strobe control circuit 200, and based on the current charging voltage information of the main capacitor C1 in the strobe unit 31, the information from the in-lens control circuit 109, the absolute distance information from the subject and the camera, photometry. The subject luminance information and the strobe light emission amount automatic reduction mode information are obtained from the circuit 103, respectively, and the light emission amount of the preliminary light emission is determined based on the information. The amount of light emission is determined so as to increase as the charging voltage increases, the distance increases, the brightness increases, for example. Further, photometry is performed in the same manner as in step S5. In the next step S9, the MPU 100 issues a command to the strobe control circuit 200 to control the preliminary light emission so that the determined preliminary light emission amount is obtained. The preliminary light emission is performed by the above-described flat light emission, and the amount of preliminary light emission depends on the peak value of the flat light emission, that is, the light emission amount determined in step S8 to the non-inverting input terminal of the comparator 206. This is done by setting a larger value as the light emission amount is larger. The preliminary light emission operation is stopped when a predetermined time elapses and the light emission stop circuit 204 is activated by a signal from the strobe control circuit 200 and the subsequent light emission is prohibited.

  When the process proceeds to step S10, the reflected light of the subject from the preliminary light emission is measured by the multi-segment photometric sensor 19 simultaneously with the preliminary light emission. In addition, the strobe control circuit 200 measures the direct light of the xenon tube 32a by the monitor sensor 32c and integrates it by the integration circuit 211 when the preliminary light emission is performed, and A / D converts the integrated value at the end of the preliminary light emission. Read. An appropriate integral value of the main light emission is calculated from the integrated value of the preliminary light emission, the subject reflected light photometric value of the preliminary light emission, the exposure value, the correction amount described later, and the like. In the next step S11, the main mirror 6 is raised prior to the exposure operation, and the sub mirror 7 is also moved away from the photographing optical path. In the subsequent step S12, a command is issued to the in-lens control circuit 109 so that the aperture value is based on the determined exposure amount, and the shutter control circuit 104 is driven so as to achieve the determined shutter speed value.

  In the next step S13, the main flash emission is controlled by the flash control circuit 200 during exposure (the main flash is started in synchronization with the turning on of the X contact when the shutter front curtain is completed) in accordance with the driving of the shutter. The The main light emission is controlled to the light emission amount obtained by the calculation in step S13. When the exposure operation is completed in this way, the process proceeds to step S14, the main mirror 6 and the like that have been withdrawn from the photographing optical path are lowered, and a series of light emission control is completed.

  In the next step S15, an image signal is sent to the memory controller 116, and the image is temporarily stored in the buffer memory 117. In the next step S 16, when the unprocessed image stored in the buffer memory 117 is at a level at which the load of the video signal processing circuit 108 can process the image, the image processing and the compression of the image are performed. Start storing operation. In the case of continuous shooting or the like, images are sequentially stored in the buffer memory 117, but the image processing may be stopped.

  In the next step S 17, the video signal processing circuit 108 receives the image data from the memory controller 116 and converts it into an analog signal, and displays the captured image on the monitor display 30 via the MPU 100 and the liquid crystal display driving circuit 106. Then, in the next step S18, it is determined whether or not the next frame can be shot. Here, if there is no space in the storage area of the buffer memory 117, the next frame cannot be photographed, and the process waits for completion of image processing, compression, and memory storage processing for one frame. If the storage area of the buffer memory 117 is empty, the next frame can be shot. In this case, the process returns to step S2 and waits for the switch SW1 to be turned on.

  This is the end of the main operation of the camera system according to the first embodiment.

  Next, the operation in the strobe emission amount automatic reduction mode executed in step S6 of FIG. 5 will be described using the flowchart of FIG.

  First, in step S100, it is determined whether or not the switch SW1 is ON. If it is ON, the process proceeds to step S101. If it is OFF, the process returns to step S2 in FIG. 5 and waits until the switch SW1 is turned ON again. If the switch SW1 is turned on and the process proceeds to step S101, the temperature Temp in the strobe light emitting unit 32 is measured by the temperature sensor 32d. In the next step S102, the measurement result (temperature Temp) in step S101 and a predetermined value (threshold value) T for shifting to the strobe emission amount automatic reduction mode previously stored in the EEPROM 100a of the MPU 100 are obtained. Make a comparison. As a result, if the measurement result is smaller than the predetermined value T, the process proceeds from the flow in FIG. 8 to step S7 in FIG. 5, and if the measurement result is larger than the predetermined value T, the process proceeds to step S103.

  In step S103, the result of step S102 is received. As described above, the flash emission automatic reduction mark 21c in FIG. 6C and the flash emission automatic reduction mark 61i in FIG. Let the photographer know that the reduction is working. Then, in the next step S104, in order to reduce the strobe light emission amount, the strobe control circuit 200 determines a correction amount for the main light emission appropriate light amount calculation result performed in step S10 in FIG. Tell. The correction amount estimates the temperature after light emission from the current temperature and the light emission amount at the time of shift, and calculates a value that falls within a predetermined temperature. Further, the correlation between the light emission amount and the temperature rise is obtained in advance based on the experimental results and stored in the MPU 100.

  In the next step S105, the exposure condition is changed. This is because the light emission amount is corrected in the above step S104, so that the photograph is underexposed under the exposure conditions set in advance by the photographer. When the ISO shift mode is selected, the exposure condition is changed by shifting the ISO sensitivity to the high sensitivity side so that proper exposure is achieved. When the exposure shift mode is selected, the aperture value is set to the open side when the shooting mode is the shutter priority mode, the shutter speed is set to the low speed side when the shooting priority mode is set, and the shutter time and aperture are set when the program priority mode is set. Both values are changed to the low speed side and the open side, respectively, according to the setting state of the shooting mode.

  Thus, the operation in the strobe emission amount automatic reduction mode is completed, and the process proceeds to step S7 in FIG.

  According to the first embodiment, as described in steps S101 to S105 in FIG. 8, when the temperature of the strobe light emitting unit 32 (including the temperature around the strobe light emitting unit 32) is higher than a predetermined value. Since the flash emission amount is reduced in the next strobe shooting, the strobe flashing unit 32 and its peripheral portion are prevented from being heated due to continuous flash emission, and the strobe shooting is continued without inhibiting the operation of the camera. Makes it possible to do. In other words, it is possible to prevent overheating of the flash emission unit 32 and its surroundings without prohibiting the flash shooting even when the flash shooting is performed under shooting conditions close to full flash or when the flash is continuously emitted. it can.

  At this time, since the photographing conditions are changed so as not to cause an underexposed photograph, the exposure is also appropriate. Further, when performing control to reduce the amount of emitted light, a message to that effect is displayed, so that the user does not feel uncomfortable. In addition, since the temperature detection is performed after the start of the photometric operation, the shift to the strobe emission amount automatic reduction mode can be appropriately performed.

  FIGS. 9 and 10 are diagrams related to Example 2 of the present invention. Specifically, FIG. 9 is a flowchart showing the main operation of the camera system, and FIG. 10 is a flowchart showing the operation in the strobe emission automatic reduction mode. . The configuration of the camera system is substantially the same as that shown in FIGS.

  In the first embodiment, the temperature of the strobe light emitting unit 32 is detected by the temperature sensor 32d, and the automatic light emission amount reduction control is performed based on the detection result of the temperature. In the second embodiment of the present invention, the xenon tube 32a is used. Is integrated by the monitor sensor 35, and the automatic reduction of the strobe light emission is controlled by the integrated amount. By replacing the temperature with the integrated light emission amount, the temperature sensor 32d becomes unnecessary.

  In FIG. 9, the operations other than step S205, step S213, and step S214 described below are the same as those in the first embodiment, and the description thereof is omitted.

  When the main light emission control is performed in step S212, integration of the light emission amount is started in the next step S213. As described above, the amount of light emitted from the xenon tube 32 a is sent to the monitor sensor 35 through the glass fiber 34, and the value integrated by the integration circuit 211 is integrated in the strobe control circuit 200. In the subsequent step 214, a timer for resetting or subtracting the accumulated light emission amount, which will be described later, is started.

  Next, the operation in the strobe emission amount automatic reduction mode executed in step S205 of FIG. 9 will be described using the flowchart of FIG.

  First, in step S300, it is determined whether or not the switch SW1 is ON. If it is ON, the process proceeds to step S301. If it is OFF, the process returns to step S201 in FIG. 9 and waits until the switch SW1 is turned ON again. Thereafter, when the switch SW1 is turned on, the process proceeds to step S301, where the time from the end of the previous main light emission (step S214 in FIG. 9) is determined. As a result, if this time is longer than the predetermined time, the process proceeds to step S302, and if shorter than the predetermined time, the process proceeds to step S303. Note that the relationship between the integrated light emission amount and the temperature decrease within a certain time is such that the temperature decrease decreases as the integrated light emission amount increases. Therefore, the predetermined time may be changed according to the integrated light emission amount.

  When the process proceeds to step S302, it is determined in step S301 that a predetermined time has elapsed, and therefore a sufficient decrease in the temperature of the strobe light emitting unit 32 can be expected. Therefore, resetting or subtracting the integrated light emission amount described above is performed to prevent an unnecessary light amount correction. The determination as to reset or subtraction and the amount of subtraction are determined based on the data by previously obtaining the correlation between the light emission amount and the temperature and time through experiments and storing them in the MPU 100. In step S303, the integrated light emission amount is compared with a predetermined value (threshold value) for shifting to the strobe light emission amount automatic reduction mode stored in the MPU 100 in advance. If the integrated light emission amount is smaller than the predetermined value, the flow of FIG. 10 proceeds to step S206 of FIG. 9, and if the integrated light emission amount is larger than the predetermined value, the operation proceeds to step S304.

  In step S304, in response to the result in step S303, the flash emission automatic reduction mark 21c in FIG. 6C and 61i in FIG. 7 are blinked to inform the photographer that the automatic flash emission reduction is operating. Close. Then, in the next step S305, in order to reduce the strobe light emission amount, a correction amount for the proper light emission amount calculation result performed in step S209 in FIG. 9 is determined and transmitted to the MPU 100. The correction amount is calculated by calculating the integrated light emission amount from the current integrated light emission amount and the light emission amount at the time of shift, and calculating a value that falls within the predetermined integrated light emission amount.

  In the subsequent step S306, the exposure condition is changed. This is because the light emission amount is corrected in the above step S305, so that an under photograph is obtained under the exposure conditions preset by the photographer. When the ISO shift mode is selected, the exposure condition is corrected by shifting the ISO sensitivity to the high sensitivity side so that proper exposure is achieved. When the exposure shift mode is selected, the aperture value is set to the open side when the shooting mode is the shutter priority mode, the shutter speed is set to the low speed side when the shooting priority mode is set, and the shutter time and aperture are set when the program priority mode is set. Both values are changed to the low speed side and the open side, respectively, according to the setting state of the shooting mode.

  Thus, the sequence of the strobe light emission amount automatic reduction mode ends, and the process proceeds to step S206 in FIG.

  According to the second embodiment, as described in steps S301 to S306 in FIG. 10, the strobe emission amount automatic reduction mode in which the accumulated emission amount obtained by integrating the emission amount of the xenon tube 32a by the monitor sensor 35 is stored in advance. If the value is larger than the predetermined value for shifting to, the flash light emission amount is reduced and the photographing conditions are changed, so that heating of the flash light emitting unit 32 and its peripheral part due to continuous flash emission is prevented. However, it is possible to perform strobe shooting with proper exposure without prohibiting the operation of the camera.

  FIG. 11 is a flowchart showing the operation in the strobe emission automatic reduction mode in the camera system according to Embodiment 3 of the present invention. The configuration of the camera system is substantially the same as that shown in FIGS.

  In the first embodiment and the second embodiment, the calculation value of the proper light emission amount is corrected in order to automatically reduce the strobe light emission amount. The strobe emission amount 32 is automatically reduced by moving the position of the strobe emission unit 32 to the telephoto (tele) side with respect to the focal length of the photographic lens 2. As for the main operation, either Example 1 or Example 2 is applied depending on the type of emission energy measurement described later.

  In FIG. 11, first, in step S400, it is determined whether or not the switch SW1 is ON. As a result, if it is ON, the process proceeds to step S401, and if it is OFF, it waits until the switch SW1 is turned ON again (step S2 in FIG. 5 or step S201 in FIG. 9). Thereafter, when the switch SW1 is turned on, the process proceeds to step S401, where the light emission energy in the strobe light emitting unit 32 is measured. The light emission energy indicates either the temperature of the strobe light emitting unit 32 described in the first embodiment or the integrated light emission amount of the monitor sensor 35 (PD1) described in the second embodiment, and in the third embodiment of the present invention. Either is acceptable and there is no particular limitation.

  In the next step S402, the measurement result (S) of the light emission energy in step S401 is compared with a predetermined value (threshold value) for shifting to the strobe light emission amount automatic reduction mode stored in the MPU 100 in advance. If the measurement result is smaller than the predetermined value, the flow returns to the main operation flow of FIG. 5 or FIG. 9 from the flow of FIG. On the other hand, if the measurement result is larger than the predetermined value, the process proceeds to step S403, and in response to the result in step S402, the strobe emission amount automatic reduction mark 21c in FIG. 6C and 61i in FIG. Let the photographer know that automatic volume reduction is working.

  In the subsequent step S404, the focal length information of the photographing lens 2 is transmitted from the MPU 100 to the strobe control circuit 200 via the accessory shoe contact 38 in order to reduce the strobe emission amount. In response to this, the strobe control circuit 200 drives the strobe light emitting unit driving motor 36 and moves the strobe light emitting unit 32 to the tele side by a predetermined amount with respect to the focal length of the photographing lens 2 via the strobe light emitting unit driving member 37. Moving. Here, the light emission amount is not to correct the proper light emission amount calculation value, but is controlled by the proper light emission amount calculation value corresponding to the focal length of the photographic lens 2, and the strobe light emitting unit 32. By performing the position correction, the amount of flash emission is automatically reduced.

  In the next step S405, the exposure condition is changed. This is because the light emission amount is corrected by moving the strobe light emitting unit 32 in the optical axis direction in the above step S404, so that underexposure is set under the exposure conditions preset by the photographer. When the ISO shift mode is selected, the exposure condition is corrected by shifting the ISO sensitivity to the high sensitivity side so that proper exposure is achieved. When the exposure shift mode is selected, the aperture value is set to the open side when the shooting mode is the shutter priority mode, the shutter speed is set to the low speed side when the shooting priority mode is set, and the shutter time and aperture are set when the program priority mode is set. Both values are changed to the low speed side and the open side, respectively, according to the setting state of the shooting mode.

  In the next step S406, since the strobe light emitting unit 32 is moved to the tele side by a predetermined amount with respect to the focal length of the photographing lens 2 in step S404, the peripheral light amount of the photographed image is reduced. For this reason, a correction value for the decrease in peripheral light amount is calculated in advance in the MPU 100 and transmitted to the video signal processing circuit 108, and the image is corrected after the photographing is completed.

  This completes the operation of the automatic flash emission amount reduction mode.

  According to the third embodiment, when the temperature of the strobe light emitting unit 32 becomes higher than a predetermined threshold value, or the strobe in which the accumulated light emission amount obtained by integrating the light emission amount of the xenon tube 32a by the monitor sensor 35 is stored in advance. If the flash emission amount is larger than the predetermined value for shifting to the automatic emission amount reduction mode, the strobe light emitting unit is set to the telephoto side by a predetermined amount from the focal length of the photographing lens 2 in order to reduce the flash emission amount. 32 is moved and the shooting conditions are changed so as not to cause an underexposed photograph. Accordingly, the flash light emitting unit 32 and its peripheral part due to continuous light emission of the strobe are prevented from being heated. This makes it possible to perform strobe shooting with proper exposure without prohibiting operation.

  In each of the above embodiments, the strobe device is assumed to be an external device (external strobe unit 31). However, the present invention is not limited to this, and a built-in strobe device in which the strobe device and the camera are integrated. It may be adapted to the camera, and the light emission control of the strobe device is not limited to the above embodiments.

  According to the above first to third embodiments, energy obtained by flash light emission, such as the temperature of the strobe light emitting unit or the amount of emitted light, is measured, and when the energy reaches a predetermined amount, control is performed to reduce the flash light emission amount and photographing. Because the conditions are changed, it is possible to perform strobe shooting with proper exposure without prohibiting the operation of the camera while preventing the flash emission part and its surroundings from being heated by continuous flash emission Become.

  The present invention has the effect of enabling continuous flash photography without prohibiting the operation of the camera, while preventing the flash light emitting part and its peripheral part from being heated by continuous light emission of the flash, from the camera and the external flash device. It is useful for a camera system or a camera system with a built-in strobe device.

It is a block diagram which shows the outline of the electronic camera system concerning Example 1 of this invention. It is a figure which shows the mode of division | segmentation of the photometry area on an imaging | photography screen, and an internal liquid crystal display in Example 1 of this invention. It is a block diagram which shows the circuit structure of the electronic camera system of FIG. 1 is a circuit diagram of a strobe unit provided in an external strobe device according to Embodiment 1 of the present invention. FIG. It is a flowchart which shows the basic operation | movement of the electronic camera concerning Example 1 of this invention. It is a figure which shows the display content of the internal liquid crystal display with which the electronic camera of FIG. 5 is equipped. It is a figure which shows the display content of the external liquid crystal display with which the electronic camera of FIG. 5 is equipped. It is a flowchart which shows the operation | movement at the time of strobe light emission automatic reduction mode concerning Example 1 of this invention. It is a flowchart which shows the basic operation | movement of the electronic camera concerning Example 2 of this invention. It is a flowchart which shows the operation | movement at the time of strobe light emission automatic reduction mode concerning Example 2 of this invention. It is a flowchart which shows the operation | movement at the time of strobe light emission automatic reduction mode concerning Example 3 of this invention.

Explanation of symbols

2 Shooting Lens 10 Image Sensor 21 Internal Liquid Crystal Display 19 Multi-segment Photometric Sensor 31 Strobe Unit (External Strobe Device)
32 Strobe light emitting unit 32a Xenon tube 32c Monitor sensor 35 Monitor sensor 100 MPU
109 In-lens control circuit 200 Strobe control circuit

Claims (11)

  In a camera system having a flash light emission unit that emits flash light, a measurement unit that measures energy obtained by the flash light emission of the flash light emission unit, and a measurement result by the measurement unit is continuously greater than a predetermined value. And a control means for reducing the amount of flash emission during strobe photography.   In a camera system having a strobe light emitting unit that emits flash light and an irradiation angle varying unit that changes an irradiation angle of the strobe light emitting unit according to a focal length of a photographing lens, energy obtained by the flash light emission of the strobe light emitting unit is obtained. When the measurement means for measuring and the measurement result by the measurement means become larger than a predetermined value, the irradiation angle of the strobe light emitting unit at the time of continuous flash photography is photographed by the irradiation angle varying means at that time. And a control unit that changes the focal length of the lens to the telephoto side.   3. The camera system according to claim 1, wherein the measurement of energy obtained by the flash light emission is a measurement of a temperature of the strobe light emitting unit.   3. The camera system according to claim 1, wherein the measurement of energy obtained by the flash emission is measurement of an integrated amount of emission amount of the strobe light emitting unit.   5. The camera system according to claim 1, wherein when performing control to reduce the amount of flash emission, the display unit notifies that effect.   2. The camera system according to claim 1, wherein when performing control to reduce the amount of flash emission, a shooting condition at the time of shooting is changed accordingly.   3. The camera system according to claim 2, wherein when the irradiation angle of the strobe light emitting unit is changed to the telephoto side from the focal length of the photographing lens at that time, the photographing condition at the time of photographing is changed accordingly. .   8. When the illumination angle of the strobe light emitting unit is changed to the telephoto side with respect to the focal length of the photographing lens at that time, the peripheral light amount drop of the photographed image is corrected accordingly. Camera system.   The camera system according to claim 6 or 7, wherein the change of the shooting condition at the time of shooting is changing the ISO sensitivity to a high sensitivity side.   The camera system according to claim 6 or 7, wherein the change of the photographing condition at the time of photographing is to increase an exposure amount. The camera system according to claim 1, wherein the energy is measured after a photometric operation is started.

Images