Patent Publication Number: US-6343189-B1

Title: Controller for controlling a built-in flash of a camera

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a camera having a built-in flash, more particularly, to a controller for controlling the built-in flash. 
     2. Description of the Related Art 
     In cameras provided with a retractable built-in flash unit which pops up from a retracted position to a discharge position (popped-up position), the built-in flash is controlled to pop-up automatically when predetermined conditions are satisfied in a situation such as a low-light condition, and subsequently discharges at a time of exposure. Accordingly, at the time the built-in flash pops up, the user visually recognizes that the built-in flash will discharge at a shutter release. After the built-in flash automatically pops up, if the user desires to take a picture without the use of the built-in flash, he or she retracts the built-in flash into the camera body by pushing it down into the camera body. 
     However, in such conventional cameras, even if the user retracts the built-in flash into the camera body, the built-in flash pops up again automatically when predetermined conditions are again satisfied. Due to this automatic control, if the user does not want to take a picture with the use of the built-in flash at all, he or she not only needs to retract the built-in flash into the camera body, but also the currently selected mode needs to be changed from an auto-flash discharge mode (auto flash mode) to an auto-flash prohibiting mode (flash-OFF mode). This operation is troublesome. Furthermore, after the auto-flash prohibiting mode has been set, if the user wants to take a picture temporarily once or twice with the use of the built-in flash, he or she has to change the currently selected mode once again from an auto-flash discharge mode to an auto-flash prohibiting mode. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the aforementioned problems which occur in prior art. An object of the present invention is to provide a controller for controlling the built-in flash of a camera, wherein the built-in flash can be temporarily prohibited from discharging by a simple operation even if the auto flash mode has been set. 
     To achieve the object mentioned above, according to an aspect of the present invention, a camera is provided, including, a retractable built-in flash unit which is movable between a retracted position and a discharge position, and a controller which controls the built-in flash and provides an auto flash mode in which the controller allows the built-in flash to discharge automatically when necessary. In the auto flash mode, the controller moves the built-in flash from the retracted position to the discharge position when predetermined conditions are satisfied, and subsequently controls the retractable built-in flash unit to discharge automatically at a time of exposure. Furthermore, the controller temporarily prohibits the retractable built-in flash unit from automatically discharging if the retractable built-in flash unit is pushed down to the retracted position after the controller moves the retractable built-in flash unit from the retracted position to the discharge position. 
     According to this structure, the built-in flash can be temporarily prohibited from discharging by simply pushing it down to the retracted position even if the auto flash mode has been set. 
     In an embodiment, the controller prohibits the retractable built-in flash unit from moving from the retracted position to the discharge position even if the predetermined conditions are satisfied when the controller prohibits the retractable built-in flash unit from automatically discharging. 
     In an embodiment, the controller cancels the control of prohibiting the retractable built-in flash unit from automatically discharging when an exposure of the camera is completed. 
     Preferably, a main switch for turning power of the camera ON and OFF is provided, wherein the controller cancels the control of prohibiting the retractable built-in flash unit from automatically discharging when the switch is turned ON after the switch is turned OFF. 
     In an embodiment, the controller cancels the control of prohibiting the retractable built-in flash unit from automatically discharging when a predetermined period of time elapses. 
     Preferably, the camera further includes an operational member wherein the controller cancels the control of prohibiting the retractable built-in flash unit from automatically discharging after the predetermined period of time elapses from when the operation member is operated. 
     Preferably, the retractable built-in flash unit includes a flashlight emitter, and a mechanism which supports the flashlight emitter and guides the flashlight emitter to be movable between the retracted position and the discharge position. The mechanism includes a spring which continuously biases the flashlight emitter towards the discharge position, a hold mechanism for holding the flashlight emitter in the retracted position against a spring force of the spring when the built-in flash is in the retracted position, and an electric release device which releases an engagement of the hold mechanism with the flashlight emitter when activated by the controller. In the auto flash mode, the controller activates the electric release device to release the engagement so as to make the flashlight emitter move from the retracted position to the discharge position upon determining that the predetermined conditions are satisfied. 
     Preferably, the controller includes different photographic modes; an auto-exposure-mode selecting mode in which an appropriate photographic mode is automatically selected from the different photographic modes based on photographic conditions, the controller allowing the built-in flash to discharge automatically in the selected appropriate photographic mode when the built-in flash discharges at a most appropriate time of exposure; and a flash-prohibiting/auto-exposure-mode selecting mode in which an appropriate photographic mode is automatically selected from the different photographic modes based on photographic conditions, the controller prohibiting the built-in flash from discharging automatically in the selected appropriate photographic mode at a time of exposure. 
     Preferably, a mode dial is also provided, wherein the controller includes a function to select a mode from the different photographic modes, the auto-exposure-mode selecting mode and the flash-prohibiting/auto-exposure-mode selecting mode in response to an operation of the mode dial. 
     Preferably, the appropriate photographic mode is automatically selected from the different photographic modes based on a low-light condition in the auto-exposure-mode selecting mode. 
     According to another aspect of the present invention, a camera is provided, including a retractable built-in flash unit which is movable between a retracted position and a discharge position, and a controller which controls the retractable built-in flash unit. The controller moves the retractable built-in flash unit from the retracted position to the discharge position automatically at least in a low-light condition, and subsequently activates the retractable built-in flash unit to discharge at a time of exposure in an auto flash mode. The controller temporarily prohibits the built-in flash from automatically discharging if the built-in flash is pushed down to the retracted position after the controller moves the built-in flash from the retracted position to the discharge position in the auto flash mode. 
     The present disclosure relates to subject matter contained in Japanese Patent Application No. 11-178424 (filed on Jun. 24, 1999) which is expressly incorporated herein by reference in its entirety. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be described below in detail with reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view of an embodiment of a camera body of an SLR camera system, according to the present invention; 
     FIG. 2 is a perspective view of part of the SLR camera system shown in FIG. 1, seen from behind the camera body, in a state where the built-in flash of the camera body is retracted; 
     FIG. 3 is a perspective view of part of the SLR camera system shown in FIG. 1, seen from behind the camera body, in a state where the built-in flash of the camera body has popped up; 
     FIG. 4 is a schematic block diagram of fundamental elements of the SLR camera system according to the present invention, showing a state where an interchangeable lens is coupled to the camera body shown in FIG. 1; 
     FIG. 5 is a schematic block diagram of fundamental elements of the SLR camera system according to the present invention, showing a state where an interchangeable lens is coupled to the camera body shown in FIG. 1; 
     FIGS. 6A and 6B show a flow chart of an embodiment of a main process regarding fundamental operations of the SLR camera shown in FIG. 1; 
     FIG. 7 is a flow chart of the subroutine “Built-in Flash Pop-up Process” shown in FIGS. 6A and 6B; 
     FIG. 8 is a flow chart of the subroutine “Built-in Flash Forced Pop-up Process” shown in FIG. 7; 
     FIG. 9 is a flow chart of the subroutine “Built-in Flash Auto Pop-up Process” shown in FIG. 7; 
     FIG. 10 is a flow chart of the subroutine “AE Calculation Process” shown in FIG. 6; 
     FIGS. 11A and 11B show a flow chart of “Auto Flash Discharge Determination Process” shown in FIG. 10; 
     FIG. 12 is a flow chart of the subroutine “Shutter Release Process” shown in FIG. 6; 
     FIG. 13 is a flow chart of the subroutine “Exposure Process” shown in FIG. 12; and 
     FIG. 14 is a plan view of a fundamental element of the mode dial provided on the camera body shown in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows an embodiment of a camera body of an AE/AF SLR camera system to which the present invention is applied. The camera body  101  is provided on a top cover  103  thereof with a release button (operational member)  105 , which is positioned on the left side of the top cover  103  as viewed in FIG.  1 . The camera body  101  is provided on the top cover  103  behind the release button  105  with a main switch knob (main switch)  107  and an external LCD panel  109 . The external LCD panel  109  indicates various photographic information such as frame number, shutter speed, aperture value and other information. The camera body  101  is provided on the top center thereof with a retractable built-in auto flash  111  which is controlled by a CPU (controller)  11  of the camera body  101  via a built-in flash control circuit  53  (see FIG.  4 ). The camera body  101  is provided thereon immediately behind the built-in flash  111  with a hot shoe  113  to which an external flash can be coupled. Although the details are not herein discussed, the built-in flash  111  is provided therein with a flashlight unit including a reflector, a xenon tube (flashlight emitter) and a Fresnel lens. The flashlight unit is supported and driven by a pop-up mechanism so that the unit can move between a retracted position (see FIGS. 1 and 2) and a pop-up position (discharge position) (see FIG. 3) where the Fresnel lens faces the object. The pop-up mechanism is provided with a spring  153  which continuously biases the built-in flash  111  towards the pop-up position and a hold mechanism for holding the built-in flash  111  at the retracted position against the spring force of the aforementioned spring  153  when the built-in flash  111  is retracted. The holding mechanism is provided with an engaging lever (hold mechanism)  151  (see FIG. 3) which comes into engagement with a hook portion (not shown) formed on a moving part of the built-in flash  111  to hold the same in the retracted position when the built-in flash  111  is pushed down to the retracted position. The engaging lever  151  is movable so as to disengage from the hook portion. The engaging lever  151  is moved in a direction to disengage from the hook portion when power is supplied to a pop-up magnet (electric release device) PuMg (see in FIG.  4 ). Therefore, if power is supplied to the pop-up magnet PuMg when the built-in flash is in the retracted position, the engaging lever  151  disengages from the hook portion, so that the built-in flash  111  pops up by the spring force of the spring  153 . The camera body  101  is provided with a forced pop-up button  119 . Power is supplied to the pop-up magnet PuMg by an operation of the forced pop-up button  119  to make the built-in flash  111  pop up. 
     The camera body  101  is provided, on the top cover  103  on the right side thereof as viewed in FIG. 1, with a mode dial  121  adapted as a device for manually selecting a desired mode from different modes. The camera body  101  is provide on a front face thereof with an annular body mount  115  to which an interchangeable lens  61  (see FIGS. 2 and 3) is detachably attached. The camera body  101  is provided on the body mount  115  with an array of contacts  117  which come into contact with a corresponding array of contacts provided on the interchangeable lens  61  so that the CPU  11  can communicate with a lens CPU  63  (see FIG. 4) to input various lens information such as open aperture value and focal length to the CPU  11 . 
     The mode dial  121  is provided with a mode indication disk (indication member)  123  fixed to the top cover  103  and a bezel  125  rotatably fitted around the mode indication disk  123 . The mode indication disk  123  is provided thereon circumferentially about a central axis thereof with a plurality of characters (thirteen characters  124   a  through  124   m  in this particular embodiment) each representing a corresponding mode. Namely, there are thirteen modes which can be selected by operating the mode dial  121 . The bezel  125  is provided with an index mark  127 . After the bezel  125  is rotated manually, it always stops by a click-stop mechanism so that the index mark  127  is set at (points to) one of the plurality of characters  124   a  through  124   m . When the index mark  127  is set to one of the thirteen characters  124   a  through  124   m , the corresponding one of the thirteen modes is selected. 
     The thirteen characters  124   a  through  124   m  are classified into two groups: the first group  123   a  including eight characters  124   a  through  124   h  and the second group  123   b  including the remaining five characters  124   i  through  124   m  (refer to FIG.  14 ). Portions of the mode indication disk  123  which respectively correspond to the first group of characters  123   a  are designed to be translucent so that each character in the first group  123   a  can be illuminated by a corresponding light emitter from the bottom (behind) of the mode indication disk  123  (i.e., from the inside of the camera body  101 ). None of the characters in the second group  123   b  are illuminated by a light emitter. 
     Control system of the camera body  101  will be hereinafter discussed in detail with reference to FIGS. 4 and 5. The camera body  101  is provided with the CPU  11  which comprehensively controls the overall operations of the camera system. The CPU  11  is provided therein with a ROM in which control programs regarding various functions of the camera are written and a RAM for temporarily storing information such as various parameters and lens information. As shown in FIG. 4, in addition to the CPU  11 , the camera body  101  is provided therein with a voltage regulator  15 , an oscillator  17 , a first motor driver IC  19 , a charge motor  21 , a second motor driver IC  23 , a film wind motor  25 , a third motor driver IC  27 , an AF motor  29 , an AF photo-interrupter  31 , an AF CCD image sensor  33 , a shutter control circuit  35 , a diaphragm control circuit  37  and an EEPROM  39 . The camera body  101  is further provided therein with a photometering IC  41 , an aperture value detection resistor  43 , a finder LCD  45 , a pair of LEDs (green and red LEDs)  47  and eight LEDs (picture mode character illumination LEDs/illumination device)  51  ( 51   a  through  51   h ). The camera body  101  is further provided therein with a main switch SWM, a photometering switch SWS, a release switch SWR, a forced pop-up switch SWPu, a pop-up state detection switch SWPud and a mode dial switch SWMod. 
     The EEPROM  39 , in which information about the number of exposure of a film roll, and various re-writable parameters and modes are written, is connected to the CPU  11 . Power of a battery  13  accommodated in a battery chamber (not shown) of the camera body  101  is supplied to the CPU  11  as a constant voltage power via the voltage regulator  15 . The CPU  11  supplies the constant voltage power to the oscillator  17  to cause the oscillator  17  to output clock pulses. The CPU  11  operates in synchronism with the clock pulses output from the oscillator  17 . 
     The main switch SWM, the photometering switch SWS, the release switch SWR, the forced pop-up switch SWPu, the pop-up state detection switch SWPud and the mode dial switch SWMod are each connected to the CPU  11 . The mode dial switch SWMod is interconnected with the bezel  125 . 
     The main switch SWM is interconnected with the main switch knob  107  so that the main switch SWM is turned ON when the main switch knob  107  is operated. If the main switch SWM is turned ON, the CPU  11  starts operating, so that the CPU  11  supplies power to peripheral elements and at the same time the CPU  11  starts performing various operations which correspond to the ON/OFF states of the switches operated. 
     The photometering switch SWS and the release switch SWR are interconnected with the release button  105  so that the photometering switch SWS and the release switch SWR are turned ON when the release button  105  is depressed half-way down and fully depressed, respectively. Immediately after the photometering switch SWS is turned ON, the CPU  11  inputs a photometering signal from the photometering IC  41  to calculate the object brightness. Based on this object brightness, the CPU  11  performs an AE calculation process (“AE Calculation Process” shown in FIG. 10) in which the optimum shutter speed and the optimum aperture value in the selected exposure mode are calculated. At the same time the CPU  11  inputs video signals of the object image from the AF CCD image sensor (a phase-difference detection CCD sensor)  33  to calculate the amount of defocus to perform an AF process (“AF Process” shown in FIG.  6 B). In the AF process, the CPU  11  drives the AF motor  29  by an amount corresponding to the amount of defocus via the motor driver IC  27  to move a focusing lens group L of the interchangeable lens  61  to an axial position where an in-focus state is obtained. Rotation of the AF motor  29  is transmitted to a joint  66  provided in the interchangeable lens  61  via an AF coupler  30  to drive an focal length adjusting mechanism  67  in the interchangeable lens  61  via the AF coupler  30  and the joint  66  to thereby move the focusing lens group L to an axial position thereof where an in-focus state is obtained. The AF photo-interrupter  31  outputs pulses in association with rotation of the AF motor  29  so that the number of pulses output from the AF photo-interrupter  31  corresponds to the amount of movement of the focusing lens group L. The CPU  11  inputs pulses output from the AF photo-interrupter  31  to control the amount of driving of the AF motor  29  in accordance with the inputs pulses. The photometering IC  41  is provided with a multi-segment photometering sensor, so that the camera measures and compares photometric readings in segmented areas of the photographic field. 
     Immediately after the release switch SWR is turned ON, the CPU  11  drives a quick-return mirror  160  (see FIG.  1 ) to rise, controls the diaphragm control circuit  37  to stop down the iris diaphragm of the interchangeable lens  61  in accordance with the aperture value determined by the AE calculation process and subsequently controls the shutter circuit  35  to release the shutter (focal plane shutter) in accordance with the determined shutter speed. Upon the completion of exposure, the CPU  11  drives the charge motor  21  via the motor driver IC  19  to make the quick-return mirror  160  fall back and to charge the shutter mechanism, i.e., charge the drive springs of the leading and trailing curtains of the shutter mechanism. Subsequently the CPU  11  drives the film wind motor  25  via the motor driver IC  23  to wind film by one frame. 
     The forced pop-up switch SWPu is interconnected with the forced pop-up button  119 , provided on the camera body  101  in the vicinity of the built-in flash  111 . Immediately after the forced pop-up switch SWPu is turned ON, i.e., the forced pop-up button  119  is depressed, the CPU  11  turns a switching transistor Tr 1  (shown in FIG. 4) ON to supply power to a pop-up magnet PuMg (shown in FIG. 4) to thereby release the engagement of the hold mechanism with the built-in flash  111  held at the retracted positioned thereof by the hold mechanism. Upon the release of the engagement of the hold mechanism with the built-in flash  111 , the built-in flash  111  pops up by the aforementioned spring  153  of the pop-up mechanism to be positioned at discharge position. The CPU  11  detects that the built-in flash  111  has popped up to the discharge position via the pop-up state detection switch SWPud, which is turned ON when the built-in flash  111  rises to the discharge position. The pop-up state detection switch SWPud is turned OFF when the built-in flash  111  moves from the discharge position towards the retracted position. 
     If the CPU  11  detects low-light and/or backlight conditions in accordance with data such as object brightness data obtained from the photometering IC  41  and ISO speed data, the CPU  11  supplies power to the pop-up magnet PuMg to make the built-in flash  111  pop-up so as to make it discharge automatically. When an external flash  71  (see FIG. 4) is attached to the hot shoe  113 , the CPU  11  prohibits the built-in flash  111  from popping up to prevent the built-in flash  111  from bumping against the external flash  71  when the CPU  11  controls the external flash  71  instead of the built-in flash  111 . 
     The mode dial switch SWMod is a four-bit code switch which is turned ON and OFF in accordance with the rotational stop position (click-stop position) of the bezel  125 . The CPU  11  selects one of the thirteen modes, functions or parameters which corresponds to one of the thirteen characters  124   a ,  124   b ,  124   c ,  124   d ,  124   e ,  125   f ,  125   g ,  125   h ,  125   i ,  125   j ,  125   k ,  125   l  or  125   m  which the index mark  127  is set to, i.e., which corresponds to the click-stop position of the bezel  125  (see FIG.  14 ). 
     The mode dial  121  is provided therein with the aforementioned eight LEDs (picture mode character illumination LEDs)  51  ( 51   a  through  51   h ) so that each LED can light up the corresponding one of the eight characters  124   a  through  124   h . Eight transistor Tr for driving the eight LEDs (picture mode character illumination LEDs  51   a  through  51   h )  51  independently of one another which illuminate the eight characters  124   a  through  124   h  of the first group  123   a  on the mode indication disk  123 , respectively, are connected to the CPU  11 . In the illustrated embodiment, when the main switch SWM is turned ON or when one of the program modes represented by the corresponding one of the first group of characters  123   a  ( 124   a  through  124   h ) is selected by an operation of the bezel  125 , the corresponding one of the eight LEDs  51   a ,  51   b ,  51   c ,  51   d ,  51   e ,  51   f ,  51   g  and  51   h  is turned ON to illuminate the corresponding character  124   a ,  124   b ,  124   c ,  124   d ,  124   e ,  124   f ,  124   g  or  125   h  by turning the corresponding transistor Tr ON in a corresponding predetermined manner. 
     The finder LCD  45 , which is positioned to be seen in the viewfinder, and the external LCD panel  109  are connected to the CPU  11 . Each of the finder LCD  45  and the external LCD panel  109  indicates various photographic information such as frame number, shutter speed, aperture value and other information. In a state where the main switch SWM is OFF, nothing is indicated on the finder LCD  45  while information necessary prior to picture taking is indicated on the external LCD panel  109 . Such information includes, e.g., film status information (loaded/advance/rewind), film counter indication if film is properly loaded, and rewind completion state. In a state where the main switch SWM is ON, in addition to the film counter indication, the currently selected shutter speed/mode and other information are indicated on the external LCD panel  109 , whereas nothing is indicated on the finder LCD  45  yet until the AE calculation process starts to be performed by an operation of the mode dial  121 . After the AE calculation process is performed, the calculated optimum shutter speed, aperture value and other useful information are indicated on each of the finder LCD  45  and the external LCD panel  109 . 
     Two LEDs  47  (a green LED  47   a  and a red LED  47   b ) illuminate information indicated on the finder LCD  45 . The CPU  11  turns the green LED  47   a  ON in a normal photographic condition, while the CPU  11  turns the red LED  47   b  ON in a warning condition (e.g., when the selected shutter speed is slower than a slowest shutter speed calculated to prevent blurred images due to hand movement) to illuminate the finder LCD  45  by red light so as to warn the user that a desired photographic image will not be obtained. 
     In a state where the interchangeable lens  61  having the lens CPU  63  is coupled to the camera body  101 , the CPU  11  data-communicates with the lens CPU  63  to input various lens information such as the focal length (the current focal length if the lens  61  is of a zoom lens), the object distance (the position of the focal lens group L) and the open aperture value. The lens CPU  63  detects the focal length via a focal length detection code plate  64  (see FIG. 5) and further detects the object distance (the position of the focal lens group L) via a distance code plate  65  to send the detected focal length and the detected object distance to the CPU  11  of the camera body  101 . 
     [Main Process] 
     A main process (“MAIN” shown in FIGS. 6A and 6B) is performed with the battery  13  loaded in the camera body  101 . Immediately after the battery cover (not shown) of the camera body  101  is closed with the battery  13  loaded therein, a CPU initializing process is performed in which each of input and output ports and the internal RAM of the CPU  11  are initialized (step S 11 ). Subsequently, peripheral circuits connected to the input and output ports are also initialized (step S 13 ). Subsequently, a reference timer in the CPU  11  is started (step S 15 ). The operations at steps S 11 , S 13  and S 15  are performed immediately after the battery cover is closed with the battery  13  loaded in the camera body  101 , and thereafter operations at and after step S 17  are repeatedly performed with the battery  13  loaded. 
     A 250 ms interval timer in the CPU  11  is started (step  517 ), an ON/OFF state of each switch is input in the CPU  11  (step S 19 ), and it is determined whether the main switch SWM is ON (step S 21 ). The 250 ms interval timer is adapted to set intervals at which the CPU  11  periodically checks if the main switch SWM is ON. 
     If it is determined at step S 21  that the main switch SWM is OFF, control proceeds to step S 23  at which an external LCD indication process is performed in which the external LCD  109  is controlled to indicate a character or characters which informs the user that the power is currently OFF. Subsequently, the LEDs  51   a  through  51   h  are turned OFF (step S 25 ). Subsequently, it is determined whether 250 ms has elapsed since the 250 ms interval timer started (step S 27 ). 
     If it is determined at step S 27  that 250 ms has elapsed, it is checked whether a three-minute timer has already started (S 28 - 1 ). The three-minute timer is started when the main switch SWM is OFF (S 55 : Y; S 94 ), or after the photometering switch SWS has been turned OFF (S 87 : N; [S 91 , S 93 ] S 94 ). 
     If the three-minute timer has already been started (S 28 - 1 : Y), it is checked whether three minutes have elapsed, i.e., whether three minutes have elapsed from when the three-minute timer started (S 28 - 2 ). When three minutes have elapsed, the flashlight prohibition flag is set to 0 (S 28 - 3 ), the three-minute timer is stopped, and control returns to step S 17  (S 28 - 4 ; S 17 ). In other words, the flashlight prohibition is automatically released after three minutes. 
     The flashlight prohibition flag is not set to 0 if the three-minute timer has not started (S 28 - 1 : N), or in the case where three minutes have started wherein three minutes have not yet elapsed (S 28 - 1 :Y; S 28 - 2 : N). The aforementioned operations from step S 17  to step S 27  are repeatedly performed during the time the main switch SWM is OFF. 
     If it is determined at step S 21  that the main switch SWM is turned ON, control proceeds to step S 29  at which it is determined if the main switch SWM was previously OFF. If it is determined at step S 29  that the main switch SWM was previously OFF, it means that control has entered the operation at step S 29  for the first time since the main switch SWM was turned ON, therefore, control proceeds to step S 30  at which a flashlight prohibition flag for prohibiting the built-in flash  111  from discharging is set to 0. When the main switch is turned ON from OFF, even if three minutes have not elapsed after the photometering switch SWS or the main switch SWM is turned OFF, the flashlight prohibition flag is set to 0 at step S 30 . Thereafter, control proceeds to step S 31  at which an opening indication process is performed. In the opening indication process, each of the eight LEDs  51   a  through  51   h  is firstly turned ON and subsequently turned OFF in accordance with a predetermined algorithm, and only one of the eight LEDs  51   a  through  51   h  which corresponds to one of eight program modes (the flash-prohibiting auto picture mode, the night portrait mode, the sports action mode, the close-up mode, the landscape mode, the portrait mode, the standard mode, and the auto picture mode) selected last by the bezel  125  is turned ON at the end. If it is determined at step S 29  that the main switch SWM was not previously OFF, control skips step S 31  to proceed to step S 33 . 
     In the auto picture mode, the CPU  11  performs a predetermined calculation in accordance with the lens data input from the lens CPU  63  to automatically select the most appropriate programmed exposure mode from five different programs (i.e., five picture modes: the sports action mode, the close-up mode, the landscape mode, the portrait mode and the standard mode). In the most appropriate programmed exposure mode selected in the auto picture mode, the CPU  11  controls the built-in flash  111  to automatically discharge in a low-light condition. The flash-prohibiting auto picture mode is identical to the auto picture mode except that the built-in flash  111  is prohibited from discharging, and hence, is prohibited from popping up in the flash-prohibiting auto picture mode. Accordingly, a programmed exposure mode, which is selected by the CPU  11  from the aforementioned five different program modes in the auto picture mode, is also an auto flash mode in which the built-in flash is allowed to discharge automatically at a time of exposure when necessary. Furthermore, a programmed exposure mode, which is selected by the CPU  11  from the aforementioned five different program modes in the flash-prohibiting auto picture mode, is also a flash OFF mode in which the built-in flash is prohibited from discharging at a time of exposure. 
     According to the above described operations in steps S 87  through S 94 , steps S 17  through  28 - 4 , steps S 21 , S 29  and S 30 , even if the built-in flash  111  is manually retracted from a pop-up position and the flashlight prohibition flag has been set to 1, if three minutes elapse after the photometering switch SWS is turned OFF wherein the release operation or the main switch SWM are not operated, i.e., after the photometering switch SWS is turned OFF and the camera is left for three minutes, the flashlight prohibition flag is automatically set to 0. In other words, although an auto-flash prohibiting mode is maintained for three minutes, if the user forgets that the auto-flash prohibiting mode has been set and leaves the camera for over three minutes, the camera automatically returns to an auto-flash discharge mode after three minutes. Therefore, upon a subsequent photographic operation, the auto-flash discharge mode can be used, hence preventing an erroneous photographic operation from occurring. 
     A built-in flash pop-up process (“Built-in Flash Pop-up Process” described in FIG. 7) is performed at step S 33 . In the built-in flash pop-up process, if it is determined that the forced pop-up switch SWPu is ON, the switching transistor Tr 1  is turned ON to supply power to the pop-up magnet PuMg to make the built-in flash  111  pop-up. Details of the built-in flash pop-up process will be discussed later. 
     It is determined at step S 35  whether the pop-up state detection switch SWPud is ON, i.e., whether the built-in flash  111  has popped up. If it is determined at step S 35  that the pop-up state detection switch SWPud is ON, control proceeds to step S 37  at which a built-in flash charging process is performed. If it is determined at step S 35  that the pop-up state detection switch SWPud is OFF, control skips step S 37  to proceed to step S 39 . 
     An LCD indication process is performed at step S 39 . In this LCD indication process in a power ON state of the camera body  101 , useful information such as the currently-selected shutter speed is indicated on the external LCD panel  109 , while nothing is indicated on the finder LCD  45  until the AE calculation process starts to be performed by an operation of the mode dial  121 . 
     It is determined at step S 41  whether the photometering switch SWS is turned ON. It is determined at step S 43  whether the release switch SWR is turned ON. If neither the photometering switch SWS nor the release switch SWR are turned ON, it is determined at step S 45  whether a state of the mode dial switch SWMod has changed. If it is determined at step S 45  that the state of the mode dial switch SWMod has not changed, control returns to step S 27 . 
     Control proceeds to step S 49  if it is determined at step S 41  that the photometering switch SWS is turned ON, if it is determined at step S 43  that the release switch SWR is turned ON, or if it is determined at step S 45  that the state of the mode dial switch SWMod has changed. 
     A photometering timer setting process is performed at step S 49 . In the photometering timer setting process, the number of times of performing a switch check process from step S 53  to step S 87  is set to a predetermined number of times. Following the photometering timer setting process, the CPU  11  waits for the release switch SWR to be turned ON while performing the switch check process at intervals shorter than the intervals of the 250 ms interval timer. Further, in the case where the release switch SWR is not yet turned ON even if the switch check process has performed the aforementioned predetermined number of times, control returns to step S 17 . In the present embodiment, the interval timer used in the photometering timer setting process is an 125 ms interval timer (photometering timer), and the number of times of performing the switch check process is set to 80 to be registered in a counter (COUNTER). 
     After the photometering timer setting process is performed at step S 49 , the 125 ms interval timer is started (step S 51 ). Thereafter, an ON/OFF state of each switch is input in the CPU  11  (step S 53 ) and subsequently it is determined whether the main switch SWM is OFF (step S 55 ). If it is determined at step S 55  that the main switch SWM is OFF, control proceeds to step S 91  at which a backlight for the finder LCD  45  is turned OFF, the LEDs  51   a  through  51   h  are turned OFF (step S 93 ). Subsequently, flashlight prohibition flag is set to 0 (step S 94 ) and control returns to step S 17 . If it is determined at step S 55  that the main switch SWM is ON, control proceeds to step S 57 . 
     At step S 57  the lens data including the F-number at open aperture, the current focal length, and the information on flashlight interruption of the built-in flash  111  by the attached lens are input to the CPU  11 . Subsequently, the photometered value (brightness value Bv) is input to the CPU  11  from the photometering IC  41  (step S 59 ), and the set aperture value is input (step S 61 ). The set aperture value, which is set by manually rotating an aperture setting ring (not shown) of the photographic lens  61 , is detected from the resistance value of an aperture value detection resistor  43 . In the case where the aperture setting ring is set to setting “A” (auto), the CPU  11  does not use the information on the resistance value of the aperture value detection resistor  43  but calculates the aperture value Av in the AE calculation process which is performed at step S 63 . 
     The shutter speed or time value Tv and the aperture value Av are calculated in the AE calculation process (“AE Calculation Process” described in FIG. 10) at step S 63 . In the AE calculation process, the optimum shutter speed Tv and the optimum aperture value Av are calculated based on the photometered value, the film speed and the exposure compensation value, in accordance with a predetermined algorithm which corresponds to the selected exposure mode. Details on the AE calculation process will be discussed later. 
     After the AE calculation process is performed, the built-in flash pop-up process (“Built-in Flash Pop-up Process” described in FIG. 7) is performed in accordance with the set shutter speed Tv and the set aperture value Av (step S 65 ). In the built-in flash pop-up process, it is determined whether the built-in flash  111  needs to pop-up, and power is supplied to the pop-up magnet PuMg to make the built-in flash  111  pop-up if it is determined that the built-in flash  111  needs to pop-up. Details of the built-in flash pop-up process will be discussed later. After the built-in flash pop-up process is performed at step S 65 , it is determined whether the built-in flash  111  has popped up (step S 67 ). If it is determined that the built-in flash  111  has popped up, control proceeds to step S 69  at which the built-in flash charging process is performed and thereafter control proceeds to step S 71 . If it is determined that the built-in flash  111  has not yet popped up, control skips step S 69  to proceed to step S 71 . 
     An LCD indication process is performed at step S 71 . In this LCD indication process, various useful information such as the set shutter speed is indicated on the external LCD panel  109 , while various useful information such as a current focus state, the set shutter speed, a hand-shake warning indication and flash discharge mode are indicated on the finder LCD  45  while the user is viewing an object through the finder. 
     Thereafter, a finder LCD backlight lighting process is performed at step S 73 . In the finder LCD backlight lighting process, the green LED  47   a  is turned ON in a normal photographic condition, while the red LED  47   b  is turned ON in a warning condition (e.g., when the selected shutter speed is slower than the slowest shutter speed calculated to prevent blurred images due to hand movement). 
     After the finder LCD backlight lighting process is performed at step S 73 , a picture mode indication lighting process is performed at step S 75 . In the picture mode indication lighting process, in the case where the auto picture mode or the flash-prohibiting auto picture mode is selected, one of the LEDs  51   a  through  51   h  which corresponds to the programmed exposure mode which has been selected in the AE calculation process at step S 63  is turned ON. Details of the picture mode indication lighting process will be discussed later. 
     After the picture mode indication lighting process is performed at step S 75 , the AF process is performed at step S 77 . In the AF process, the AF CCD image sensor  33  is driven, video signals of object images are input to the CPU  11 , and the AF motor  29  is driven by an amount corresponding to the amount of defocus to move the focusing lens group L of the interchangeable lens  61  to an axial position where an in-focus state is obtained. 
     Subsequently, it is determined whether the release switch SWR is turned ON (step S 79 ). Control returns to step S 49  upon performing a shutter release process (S 95 ) if it is determined at step S 79  that the release switch SWR is turned ON. If it is determined at step S 79  that the release switch SWR is not turned ON, it is determined at step S 81  whether 125 ms has elapsed (i.e., whether the 125 ms interval timer is up). If it is determined at step S 81  that 125 ms has not yet elapsed, the operation at step S 81  is repeatedly performed to wait for the 125 ms interval timer to elapse. If it is determined at step S 81  that 125 ms has elapsed, it is determined whether the counter value is zero (step S 83 ). If it is determined that the counter value is not zero, the counter value is decreased by one (step S 85 ) and control returns to step S 53 . Accordingly, during the time the main switch SWM is ON while the release switch SWR is OFF, the operations from step S 53  through step S 85  are repeatedly performed eighty times until the counter value, whose initial value is 80, becomes zero. Note that 10 seconds (125 ms 80=10 sec) elapses if the operations from step S 53  through step S 85  are repeatedly performed eighty times. 
     If it is determined at step S 83  that the counter value is zero, control proceeds to step S 87  at which it is determined whether the photometering switch SWS is turned ON. If it is determined the photometering switch SWS is turned ON, control returns to step S 53 . Namely, even if ten seconds elapses, the operations at step S 53  through step S 83  and step S 87  are repeatedly performed as long as the photometering switch SWS is ON. If it is determined at step S 87  that the photometering switch SWS is not ON, control proceeds to step S 91  at which the backlight for the finder LCD  45  is turned OFF (step S 91 ), Subsequently, the LEDs  51   a  through  51   h  are turned OFF (step S 93 ), the flashlight prohibition flag is set to 0 (step S 94 ) and control returns to step S 17 . At step S 91 , the CPU  11  turns OFF one of the LEDs  51   a  through  51   h  which corresponds to the programmed exposure mode selected in the AE calculation process at step S 63  and which is turned ON in the picture mode indication lighting process at step S 75  in the case where the auto picture mode or the flash-prohibiting auto picture mode is selected. 
     [Built-in Flash Pop-up Process] 
     The built-in flash pop-up process, which is performed at step S 33  or S 65  in the main process shown in FIGS. 6A and 6B, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  7 . In this process, the switching transistor Tr 1  is turned ON to supply power to the pop-up magnet PuMg to make the built-in flash  111  pop-up on condition that a mode other than the flash-prohibiting auto picture mode is selected and that conditions necessary for having the built-in flash  111  discharge are all set. Furthermore, if the built-in flash  111  is forcibly retracted (e.g., manually by the user) after the built-in flash  111  is popped up, the built-in flash  111  is prohibited from popping up automatically until the photometering timer, which is started at step S 51 , has elapsed. 
     In the built-in flash pop-up process, firstly it is determined whether the flash-prohibiting auto picture mode has been selected (step S 201 ). If the flash-prohibiting auto picture mode has been selected, the built-in flash  111  is prohibited from discharging, so that control returns. 
     If it is determined at step S 201  that the flash-prohibiting auto picture mode is not selected (i.e., a mode other than the flash-prohibiting auto picture mode is selected), it is determined whether the flashlight prohibition flag is 1 (step S 203 ). If the flashlight prohibition flag is not 1, it is determined whether the built-in flash  111  has popped up (step S 205 ). The default of the flashlight prohibition flag is set to zero. If it is determined at step S 203  that the flashlight prohibition flag is 1 or it is determined at step  205  that the built-in flash  111  has popped up, control returns to the main process. If it is determined at step  205  that the built-in flash  111  has not popped up, it is determined whether an auto-pop-up flag is 1 (step S 207 ). The auto-pop-up flag indicates whether the built-in flash  111  has automatically popped up. The default of the auto-pop-up flag is set to zero. The auto-pop-up flag is set to 1 at step S 251  shown in FIG.  9 . 
     If it is determined at step S 207  that the auto-pop-up flag is zero, a built-in flash forced pop-up process (“Built-in Flash Forced Pop-up Process” described in FIG. 8) is performed (step S 213 ). Subsequently, it is determined whether an auto-flashlight permission flag is 1 (step S 215 ). If it is determined at step S 213  that the auto-flashlight permission flag is 1, a built-in flash auto pop-up process (“Built-in Flash Auto Pop-up Process” described in FIG. 9) is performed (step S 217 ) and subsequently control returns to the main process. If it is determined at step S 215  that the auto-flashlight permission flag is not 1, control returns to the main process. The auto-flashlight permission flag indicates whether the built-in flash  111  is permitted from discharging automatically. The default of the auto-flashlight permission flag is set to zero. If it is determined at step S 207  that the auto-pop-up flag is 1, control proceeds to step S 209  at which the flashlight prohibition flag is set to 1. Subsequently, the auto-pop-up flag is set to 0 (step S 211 ), and control returns to the main process. 
     In other words, after the built-in flash automatically pops up due to the built-in flash auto pop-up process (S 217 ), if the user manually retracts the built-in flash into the retracted position, although the built-in flash is not in a popped up state, since the auto-pop-up flag is 1, control proceeds from step S 207  to step S 209  so that the flashlight prohibition flag is set to 1. 
     If the built-in flash forced pop-up process (“Built-in Flash Forced Pop-up Process” described in FIG. 8) is made to be performed before control returns from the operation at step S 203  (see FIG. 7) to the main process on condition that the flashlight prohibition flag is 1 at step S 203 , the built-in flash forced pop-up process is performed upon an operation of the forced pop-up button  119  even if the built-in flash  111  is pushed down to be retracted. This makes it possible to bring the built-in flash  111  back to the discharge position after the built-in flash  111  is pushed down to be retracted, without the need of changing the currently selected mode. To realize this control, the built-in flash forced pop-up process shown in FIG. 8 needs to be further provided, after the operation at step S 237 , with an operation in which the flashlight prohibition flag is set to 0. 
     [Built-in Flash Forced Pop-up Process] 
     The built-in flash forced pop-up process, which is performed at step S 213  in the built-in flash pop-up process shown in FIG. 7, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  8 . In this process, firstly it is determined whether the forced pop-up switch SWPu (forced discharge switch) is ON (step S 231 ). If it is determined that the forced pop-up switch SWPu is ON, the pop-up magnet PuMg is turned ON (power starts to be supplied) at step S 233 . Subsequently, control waits for 5 ms so that power keeps to be supplied to the pop-up magnet PuMg for 5 ms (step S 235 ). Subsequently, the engagement of the hold mechanism with the built-in flash  111  is released by turning the pop-up magnet PuMg OFF to make the built-in flash  111  pop-up by the spring force of the spring  153  of the pop-up mechanism (step S 237 ). The pop-up state detection switch SWPud is turned ON when the built-in flash  111  has risen, so that the CPU  11  can determine that the built-in flash  111  has risen by checking the ON/OFF state of the pop-up state detection switch SWPud. It is determined at step S 231  that the forced pop-up switch SWPu is not ON, control skips the operation from step S 231  to S 237  to return to the main process. 
     [Built-in Flash Auto Pop-up Process] 
     The built-in flash auto pop-up process, which is performed at step S 217  in the built-in flash pop-up process described in FIG. 7, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  9 . As can be seen from the flow chart shown in FIG. 9, in a state where the built-in flash  111  is retracted, it is popped up through the built-in flash auto pop-up process when conditions necessary for having the built-in flash  111  discharge are all set. In the built-in flash auto pop-up process, firstly it is determined whether the pop-up state detection switch SWPud is ON so as to know if the built-in flash  111  has popped (step S 241 ). If it is determined at step S 241  that the pop-up state detection switch SWPud is ON, it means that the built-in flash  111  has already popped, so that control returns to the main process. If the pop-up state detection switch SWPud is not ON, it is determined whether an auto-pop-up permission flag is 1 while the photometering switch SWS is ON (step S 243 ). 
     The auto-pop-up permission flag is set to 1 on condition that the built-in flash  111  is retracted if it is judged in the AE calculation process (which includes an auto-discharge judging process shown in FIGS. 11A and 11B) that the built-in flash  111  should discharge. If the auto-pop-up permission flag is not 1 or the photometering switch SWS is not ON at step S 243 , control returns to the main process. If the auto-pop-up permission flag is 1 while the photometering switch SWS is ON at step S 243 , control proceeds to step S 245 . The pop-up magnet PuMg is turned ON (power starts to be supplied) at step S 245 . Subsequently, control waits for 5 ms so that power continues to be supplied to the pop-up magnet PuMg for 5 ms (step S 247 ). Subsequently, the engagement of the hold mechanism with the built-in flash  111  is released by turning the pop-up magnet PuMg OFF to make the built-in flash  111  pop-up by the spring force of the spring  153  of the pop-up mechanism (step S 249 ). Subsequently, the auto-pop-up flag is set to 1 (step S 251 ) and control returns to the main process. 
     If the built-in flash  111  is made to pop-up in the built-in flash pop-up process performed at step S 65  in the main process shown in FIG. 6B, the pop-up state detection switch SWPud is turned ON and the auto-pop-up flag is set to 1. Therefore, the next time control re-enters the built-in flash pop-up process, control comes out of the built-in flash pop-up process from step S 205  (FIG. 7) to return to the main process. On the other hand, if the built-in flash  111  is retracted manually by the user after the built-in flash  111  is popped up, the pop-up state detection switch SWPud is turned OFF, so that at step S 207  control proceeds to step S 209  in the built-in flash pop-up process when control enters it for the first time since the pop-up state detection switch SWPud is turned OFF. Thereafter, the flashlight prohibition flag is set to 1, the auto-pop-up flag is set to 0 and control returns to the main process. Thereafter, the flashlight prohibition flag remains at 1 while the photometering switch SWS is held ON until the photometering timer, which is started at step S 51 , has elapsed. Thereafter, if control enters the built-in flash pop-up process at step S 65  in the main process shown in FIG. 6B, at step S 203  control comes out of the built-in flash pop-up process to return to the main process. According to this control, even if the auto-flashlight permission flag is set to 1 and at the same time the photometering switch SWS is turned ON, the built-in flash  111  is not automatically popped up. 
     Furthermore, in the main process shown in FIG. 6A, after the three-minute timer has elapsed, the flashlight prohibition flag is set to 0 at step S 28 - 3 . If the photometering timer or the three-minute timer have elapsed, when the main switch SWM is turned ON from OFF, the flashlight prohibition flag is set to 0 at step  530 . Therefore, if control enters the built-in flash pop-up process at step S 65 , the built-in flash  111  is automatically popped up on condition that the auto-flashlight permission flag is set to 1 while the photometering switch SWS is turned ON. 
     [AE Calculation Process] 
     The AE calculation process, which is performed at step S 63  in the main process shown in FIG. 6B, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  10 . In this process, firstly, all flags which are associated with the AE calculation process such as an under-hand-shake-speed flag are set to 0 (step S 301 ). Subsequently, a predetermined compensation calculation is performed using the lens data such as the open aperture value and the minimum aperture value of the lens  61  which are input to the CPU  11  from the lens CPU  63  when the CPU  11  has data-communicated with the lens CPU  63  at step S 57  (step S 303 ). Subsequently, a brightness value is calculated on each photometering zone in accordance with the photometering signals input from the photometering IC  41  (step S 305 ), and a primary exposure value Lv′ is calculated in accordance with a multi-segment photometering algorithm (step S 307 ). Thereafter, a secondary exposure value Lv which is used for the exposure control is calculated in accordance with a film speed value Sv, an exposure compensation value Xv and the primary exposure value Lv′ (step S 309 ). 
     Subsequently, an auto picture setting process for setting an exposure mode selected by an operation of the mode dial  121  is performed (step S 311 ). Subsequently, it is judged whether the flashlight emitted from the built-in flash  111  will be interrupted by part of the attached lens  61  and at the same it is judged whether the flashlight emitted from the external flash  71  attached to the hot shoe  113  will be interrupted by part of the attached lens  61 , in accordance with the information on flashlight interruption of the built-in flash  111  by the attached lens, the information on flashlight interruption of the external flash  71  by the attached lens and the lens information on the attached lens  61  (step S 313 ). “Flashlight interruption” means that the flashlight emitted from the built-in flash  111  or the external flash  71  is interrupted by part of the attached lens  61 . Accordingly, the flashlight does not cover center lower part of the object area, so that the center lower part appears dark. In the present embodiment, in order to prevent such a problem from occurring, if it is judged at step S 313  that flashlight emitted from the built-in flash  111  and/or the external flash  71  will be interrupted by part of the attached lens  61 , this judgement is stored in the internal RAM of the CPU  11  so that the built-in flash  111  or the external flash  71  does not discharge in an auto flash discharge determination process performed at step S 315 . 
     The auto flash discharge determination process (“Auto Flash Discharge Determination Process” described in FIGS. 11A and 11B) is performed at step S 315 . If the auto-flashlight permission flag is set to 1 in the auto flash discharge determination process, the CPU  11  judges whether the built-in flash  111  or the external flash  71  should discharge in accordance with predetermined conditions in a program calculation process. Details of the auto flash discharge determination process will be discussed later If the CPU  11  judges that the built-in flash  111  or the external flash  71  should discharge, the built-in flash  111  or the external flash  71  discharges in a shutter release process (“Shutter Release Process” described in FIG. 12) at step S 95 . 
     After the auto flash discharge determination process is performed, it is determined at step S 317  whether the auto-flashlight permission flag is 1. If the auto-flashlight permission flag is 1, a flash program calculation used on a flashlight-permission condition is performed to calculate the optimum shutter speed and the optimum aperture value (step S 319 ). If the auto-flashlight permission flag is not 1, a stationary-light program calculation used on a flashlight-prohibition condition is performed to calculate the optimum shutter speed and the optimum aperture value (step S 321 ). After the operation at step S 319  or S 321  is performed, an under hand-shake speed judging process is performed (step S 323 ). 
     In the under hand-shake speed judging process it is determined whether the shutter speed calculated in the stationary-light program calculation at step S 321  or the flash program calculation at step S 319  is slower than the slowest shutter speed calculated to prevent blurred images due to hand movement. If the shutter speed calculated in the stationary-light program calculation at step S 321  or the flash program calculation at step S 319  is slower than the slowest shutter speed, the red LED  47   b  is turned ON in the finder LCD backlight lighting process at step S 73  to illuminate the finder LCD  45  by red light so as to warn the user that a desired image will not be obtained. 
     [Auto Flash Discharge Determination Process] 
     The auto flash discharge determination process, which is performed at step S 315  in the AE calculation process described in FIG. 10, will be hereinafter discussed in detail with reference to the flow chart shown in FIGS. 11A and 11B. In this process, firstly, it is determined whether the flash-prohibiting auto picture mode has been selected by checking the state of the mode dial switch SWMod (step S 341 ). If the flash-prohibiting auto picture mode has been selected, it means that the built-in flash  111  and the external flash  71  are prohibited from discharging, so that control returns to the AE calculation process. If a mode other than the flash-prohibiting auto picture mode has been selected, it is determined whether an auto flash discharge mode has been selected (step S 343 ). 
     If it is determined at step S 343  that the auto flash discharge mode is not selected, it means that a forced discharge mode has been selected, so that control proceeds to step S 345  at which it is determined whether the external flash  71  has been charged up to a discharge-ready level thereof. 
     If it is determined at step S 345  that the external flash  71  has been charged to the discharge-ready level, it is determined whether the auto flash discharge mode has been selected (step S 346 ). If the auto flash discharge mode has been selected, it is determined whether, at step S 313 , the flashlight emitted from the external flash  71  attached to the hot shoe  113  was judged as being interrupted by part of the attached lens  61  (step S 347 ). If such judgement was made at step S 313 , the external flash  71  is not permitted to discharge, and control returns to the AE calculation process. Otherwise, the auto-flashlight permission flag, which indicates whether the built-in flash  111  is permitted from discharging automatically, is set to 1 (step S 355 ) and control returns to the AE calculation process. If it is determined at step S 346  that the auto flash discharge mode is not selected, the auto-flashlight permission flag is set to 1 (step S 355 ) and control returns to the AE calculation process. 
     If it is determined at step S 345  that the external flash  71  has not yet been charged to the discharge-ready level (this is also true to the case where the external flash  71  is not attached to the hot shoe  113 ), it is determined whether the auto flash discharge mode has been selected (step S 348 ). If the auto flash discharge mode has been selected, it is determined whether it was judged at step S 313  that the flashlight emitted from the built-in flash  111  will be interrupted by part of the attached lens  61  (step S 349 ). If such a judgement was made, the built-in flash  111  is not permitted to discharge, and control returns to the AE calculation process. Otherwise, it is determined whether the built-in flash  111  has popped up by checking the ON/OFF state of the pop-up state detection switch SWPud (step S 350 ). Likewise, if it is determined at step S 348  that the auto flash discharge mode is not selected, it is determined whether the built-in flash  111  has popped up by checking the ON/OFF state of the pop-up state detection switch SWPud (step S 350 ). 
     If it is determined at step S 350  that the built-in flash  111  has popped up, it is determined whether the built-in flash  111  has been charged up to a discharge-ready level thereof (step S 351 ). If the built-in flash  111  has been charged up to the discharge-ready level, the auto-flashlight permission flag is set to 1 (step S 355 ) and control returns to the AE calculation process. If it is determined at step S 351  that the built-in flash  111  has not been yet charged up to the discharge-ready level, control returns to the AE calculation process. 
     If it is determined at step S 350  that the built-in flash  111  has not popped up, it means that the built-in flash  111  is retracted or currently on the way to the fully-popped up position and therefore is not properly directed forwardly, so that the auto-pop-up permission flag is set to 1 (step S 353 ) and subsequently control returns to the AE calculation process. 
     If the auto-pop-up permission flag is set at 1, in the built-in flash auto pop-up process control proceeds from step S 243  to step S 245  on condition that the photometering switch SWS is ON, so that the built-in flash  111  pops up automatically. 
     If it is determined at step S 343  that the auto flash discharge mode has been selected, it is determined whether the object distance, which is obtained in the data-communication of the CPU  11  with the lens CPU  63 , is equal to or shorter than a predetermined distance; namely, within a close distance range (step S 357 ). If it is determined at step S 357  that the object distance is within the close distance range, control returns to the AE calculation process. In the case where the object distance is too short, the automatic flashlight control does not work effectively. This may result in an over-exposure. In the present embodiment, if the distance value Dv is equal to or less than −1 (approximately 70 cm), the CPU  11  judges that the object distance is within the close distance range, so that in this case the CPU  11  controls each of the built-in flash  111  and the external flash  71  not to automatically discharge. 
     If it is determined at step S 357  that the object distance, which is obtained in the data-communication of the CPU  11  with the lens CPU  63 , is not equal to or less than the predetermined distance (i.e., the object distance is longer than the predetermined distance), it is determined whether one of the eight program modes (the flash-prohibiting auto picture mode, the night portrait mode, the sports action mode, the close-up mode, the landscape mode, the portrait mode, the standard mode, and the auto picture mode) has been selected (step S 359 ). If it is determined at step S 359  that a mode other than the eight program modes has been selected (i.e., one of the manual exposure mode, a shutter-priority AE mode or the program AE mode has been selected), whether the built-in flash  111  or the external flash  71  should be used or not depends on the user, so that control returns to the AE calculation process. 
     If it is determined at step S 359  that one of the eight program modes has been selected, a stationary-light program calculation is performed to calculate the optimum shutter speed and the optimum aperture value (step S 361 ). Subsequently, it is determined whether the shutter speed calculated in the stationary-light program calculation at step S 361  is slower than the slowest shutter speed calculated to prevent blurred images which may be caused by hand movement (step S 363 ). Subsequently, it is determined whether an object to be photographed is in a backlit situation in accordance with the object brightness data obtained from the photometering IC  41  (step S 365 ). If it is determined at step S 363  that the calculated shutter speed is not slower than the required slowest shutter speed, and if it is determined at step S 365  that the object to be photographed is not in a backlit situation, control returns to the AE calculation process. If it is determined at step S 363  that the calculated shutter speed is slower than the required slowest shutter speed or if it is determined at step S 365  that the object to be photographed is in a backlit situation, control proceeds to step S 345  so as to make the built-in flash  111  or the external flash  71  to discharge automatically. 
     [Shutter Release Process] 
     The shutter release process, which is performed at step S 95  in the main process shown in FIG. 6B, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  12 . In this process, firstly a mirror-engagement release magnet (not shown) is supplied with current to release the engagement of an engaging member with the quick-return mirror  160  so that the quick-return mirror  160  rises by a spring force of the spring  153  and at the same time the diaphragm control circuit  37  is controlled to stop down the iris diaphragm of the interchangeable lens  61  by an amount corresponding to the aperture value determined by the AE calculation process (step S 601 ). Immediately after it is detected with a mirror-up detection switch (not shown) that the quick-return mirror  160  has completely risen, the shutter circuit  35  starts operating to perform an exposure process (“Exposure Process” described in FIG. 13) in which the shutter circuit  35  is controlled to release the focal plane shutter in accordance with the determined shutter speed (step S 603 ). The details of the exposure process will be discussed later. Subsequently, upon the completion of the operation of the focal plane shutter a mirror-down/charge process, a shutter charge process and a film winding process are performed (Step S 605 ). In the mirror-down/charge process, the charge motor  21  is driven to make the quick-return mirror  160  swing down while the drive springs of the leading and trailing curtains of the shutter mechanism are charged. In the shutter charge process, the leading and trailing curtains are moved back to the initial positioned thereof while a shutter charging spring is charged. In the film winding process, the film motor  25  is driven to wind film by one frame. Subsequently the flashlight prohibition flag is set to 0 (step S 607 ) and control returns to the main process. 
     [Exposure Process] 
     The exposure process, which is performed at step S 603  in the shutter release process described in FIG. 12, will be hereinafter discussed in detail with reference to the flow chart shown in FIG.  13 . In this process, firstly the time value of a shutter timer is set to the value of the shutter speed (exposure) determined in the AE calculation process, and subsequently the shutter timer is started (step S 621 ). Subsequently the leading curtain of the focal plane shutter is released to start moving (step S 623 ). It is next determined whether the shutter speed determined in the AE calculation process is equal to or slower than the flash synchronization speed (step S 625 ). If the shutter speed is faster than the flash synchronization speed, neither the built-in flash  111  or the external flash  71  should discharge. Accordingly, after the operation at step S 625 , control proceeds to step S 639  at which it is determined whether the shutter timer has elapsed. If the counting of the shutter timer is up, the trailing curtain of the focal plane shutter is released to start moving (step S 641 ) and subsequently control returns to the shutter release process. 
     If it is determined at step S 625  that the shutter speed is equal to or slower than the flash synchronization speed, it is determined whether the movement of the leading curtain has completed (step S 627 ). If the movement of the leading curtain has not yet completed, control repeats the checking operation at step S 627 . Thereafter, if the movement of the leading curtain has not yet completed, it is determined whether the flash-prohibiting auto picture mode has been selected (step S 629 ). If the flash-prohibiting auto picture mode has been selected, neither the built-in flash  111  or the external flash  71  should discharge. Accordingly, control proceeds to step S 639 . If the flash-prohibiting auto picture mode has not been selected, it is determined whether the auto-flashlight permission flag is 1, i.e., whether the built-in flash  111  or the external flash  71  can discharge (step S 631 ). If the auto-flashlight permission flag is not 1, i.e., the built-in flash  111  or the external flash  71  cannot discharge, control proceeds to step S 639 . If it is determined at step S 631  that the auto-flashlight permission flag is 1, control proceeds to step S 633  at which an external flash discharge process is performed. In this process, a command signal (discharging signal) is sent to the external flash  71  to make it discharge in the case where the external flash  71  is attached to the hot shoe  113 . 
     Subsequently, it is determined whether the built-in flash  111  has risen to the discharge position by determining if the pop-up state detection switch SWPud is turned ON (step S 635 ). If the built-in flash  111  has risen to the discharge position, control proceeds to step S 637  at which a built-in flash discharge process is performed to make the built-in flash  111  discharge. In the case where the external flash  71  is attached to the hot shoe  113 , the built-in flash  111  is prohibited from popping up, so that at step S 635  control proceeds to step S 639 . 
     In the external flash discharge process at step S 633  and the built-in flash discharge process at step S 637 , normally, exposure from image light passing through the lens is measured by a suitable light-sensitive mechanism of a TTL photometering system (not shown). Subsequently, if the value of the exposure reaches the calculated exposure value, a command signal (discharge stop signal) is sent to the built-in flash  111  or the external flash  71  to stop discharging. 
     As can be understood from the foregoing, according to a controller for controlling the built-in flash of a camera, since in the auto flash mode, the controller temporarily prohibits the retractable built-in flash unit from automatically discharging if the retractable built-in flash unit is pushed down to the retracted position after the controller moves the retractable built-in flash unit from the retracted position to the discharge position, the built-in flash can be temporarily prohibited from discharging by a simple operation even if the auto-flash discharge mode (auto flash mode) has been set. 
     The control of prohibiting the built-in flash from discharging is canceled when the exposure is completed, when a predetermined period of time elapses or when the power of the camera is turned ON or OFF. Therefore, after the auto-flash prohibiting mode (flash OFF mode) has been set, even if the user wants to take a picture temporarily once or twice with the use of the built-in flash, he or she does not have to change the currently selected mode, but only needs to push the built-in flash down to the retracted position. This facilitates the ease of operation of the camera. 
     Obvious changes may be made in the specific embodiments of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention.