Abstract:
An electronic camera and method include an imaging device, a luminance detection device, a selection device, a first control circuit, a second control circuit and a third control circuit. The first control circuit re-executes an exposure calculation by adjusting the exposure sensitivity if a first control exposure determined in the first mode does not achieve the optimal exposure. The second control circuit automatically sets the exposure sensitivity at the imaging device in correspondence to a subject luminance detected by the luminance detection device. The third control circuit disallows the second control circuit from operating and allows the first control circuit to operate when the first mode is selected, and that disallows the first control circuit from operating and allows the second control circuit to operate when the second mode is selected.

Description:
INCORPORATION BY REFERENCE 
     The disclosure of the following priority application is herein incorporated by reference: 
     Japanese Patent Application No. 2006-142725 filed May 23, 2006 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic camera. 
     2. Description of Related Art 
     Japanese Laid Open Patent Publication No. 2003-189175 and Japanese Laid Open Patent Publication No. 2001-94854 respectively disclose a technology (hereafter referred to as “first control”), whereby exposure calculation is executed based upon the exposure sensitivity set at an imaging device and the subject luminance and if the optimal exposure is not achieved as a result of the initial exposure calculation, exposure calculation is executed again by adjusting the exposure sensitivity, and a technology (hereafter referred to as “second control”), whereby a specific exposure sensitivity level is selected at an imaging device in correspondence to the subject luminance. 
     When the first control and the second control are adopted in combination in an electronic camera, confusion may occur as the settings selected in the first control may not be easily distinguishable from those in the second control. 
     SUMMARY OF THE INVENTION 
     An electronic camera according to a first aspect of the present invention includes: an imaging device that captures a subject image through a photographic lens; a luminance detection device that detects subject luminance; a first arithmetic operation circuit that executes exposure calculation by using at least exposure sensitivity set at the imaging device and the subject luminance detected by the luminance detection device among the exposure sensitivity set at the imaging device, an exposure time period set at the imaging device, an aperture value set at the photographic lens and the subject luminance detected by the luminance detection device and determines through arithmetic operation a first control exposure by adjusting at least one of the exposure time period and the aperture value so as to achieve optimal exposure if the optimal exposure is not achieved through the initial exposure calculation: a second arithmetic operation circuit that determines through arithmetic operation a second control exposure with regard to the aperture value and the exposure time period so as to achieve the optimal exposure in correspondence to the exposure sensitivity set at the imaging device and the subject luminance detected by the luminance detection device; a first control circuit that controls the first arithmetic operation circuit so as to execute the exposure calculation again by adjusting the exposure sensitivity if calculation results provided by the first arithmetic operation circuit do not achieve the optimal exposure: a second control circuit that sets the exposure sensitivity at the imaging device in correspondence to the subject luminance detected by the luminance detection device; and a third control circuit that individually controls the first arithmetic operation circuit, the second arithmetic operation circuit, the first control circuit and the second control circuit such that one of the first arithmetic operation circuit and the second arithmetic operation circuit is selected in response to a first instruction, that engagement of the second control circuit is disallowed and engagement of the first control circuit is allowed in response to a second instruction when the first arithmetic operation circuit is selected and that engagement of the first control circuit is disallowed and engagement of the second control circuit is allowed in response to a third instruction when the second arithmetic operation circuit is selected. 
     According to a 2nd aspect of the present invention, in the electronic camera according to the first aspect, it is preferable that the third instruction is output from a sensitivity setting operation member operated to set the exposure sensitivity at the imaging device. 
     According to a 3rd aspect of the present invention, the electronic camera according to the 2nd aspect, it is preferable that the second instruction is output from an operation member other than the sensitivity setting operation member. 
     According to a 4th aspect of the present invention, the electronic camera according to the 2nd aspect further includes: a storage device in which information indicating the exposure sensitivity having been set most recently with the first arithmetic operation circuit selected and information indicating contents of an instruction having been most recently issued via the sensitivity setting operation member with the second arithmetic operation circuit selected are stored. And it is preferable that (1) the third control circuit selects the first arithmetic operation circuit instead of the second arithmetic operation circuit and sets the most recent exposure sensitivity indicated in the information stored in the storage device as the exposure sensitivity at the imaging device in response to the first instruction received when the second arithmetic operation circuit is selected and engagement of the second control circuit is allowed; and (2) the third control circuit selects the first arithmetic operation circuit instead of the second arithmetic operation circuit and sets exposure sensitivity corresponding to the contents of the most recent instruction issued via the sensitivity setting operation member, indicated in the information stored in the storage device, as the exposure sensitivity at the imaging device in response to the first instruction received when the second arithmetic operation circuit is selected and engagement of the second control circuit is not allowed. 
     According to a 5th aspect of the present invention, in the electronic camera according to the 4th aspect, the third control circuit may select the first arithmetic operation circuit instead of the second arithmetic operation circuit and set the exposure sensitivity at the imaging device to a predetermined sensitivity level if information indicating the most recent exposure sensitivity having been set with the first arithmetic operation circuit selected or information indicating the most recent exposure sensitivity having been set with the second arithmetic operation circuit selected is not stored in the storage device, in response to the first instruction received when the second arithmetic operation circuit is selected and engagement of the second control circuit is allowed. 
     According to a 6th aspect of the present invention, the electronic camera according to the 2nd aspect may further include a storage device in which information indicating the exposure sensitivity having been set most recently with the first arithmetic operation circuit selected and information indicating contents of an instruction having been most recently issued via the sensitivity setting operation member with the second arithmetic operation circuit selected are stored. It may be possible that (1) the third control circuit selects the second arithmetic operation circuit instead of the first arithmetic operation circuit and allows engagement of the second control circuit if information indicating the third instruction is stored in the storage device, in response to the first instruction received when the first arithmetic operation circuit is selected; and (2) the third control circuit selects the second arithmetic operation circuit instead of the first arithmetic operation circuit and sets the most recent exposure sensitivity indicated in the information stored in the storage device as the exposure sensitivity at the imaging device if information indicating the third instruction is not stored in the storage device, in response to the first instruction received when the first arithmetic operation circuit is selected. 
     According to a 7th aspect of the present invention, in the electronic camera according to the 2nd aspect, it is preferable that the third control circuit disallows engagement of the second control circuit and adjusts the exposure sensitivity from a maximum sensitivity level or a minimum sensitivity level designated as a starting point in response to an instruction for setting the exposure sensitivity output from the sensitivity setting operation member when the second arithmetic operation circuit is selected and engagement of the second control circuit is allowed. 
     According to a 8th aspect of the present invention, in the electronic camera according to the first aspect, the first control circuit may control the first arithmetic operation circuit so as to adjust the exposure sensitivity by setting the exposure time period to a predetermined value indicating a higher speed than a lower control limit. 
     According to a 9th aspect of the present invention, the electronic camera according to the 2nd aspect may further includes a storage device in which information indicating the exposure sensitivity having been set most recently with the first arithmetic operation circuit selected and information indicating contents of an instruction having been most recently issued via the sensitivity setting operation member with the second arithmetic operation circuit selected are stored. It may be possible that (1) the third control circuit selects the first arithmetic operation circuit instead of the second arithmetic operation circuit and sets one of the most recent exposure sensitivity indicated in the information stored in the storage device and exposure sensitivity corresponding to the contents of the most recent instruction issued via the sensitivity setting operation member and indicated in the information stored in the storage device, as the exposure sensitivity at the imaging device, in response to the first instruction received when the second arithmetic operation circuit is selected and engagement of the second control circuit is allowed; and (2) the third control circuit selects first arithmetic operation circuit instead of the second arithmetic operation circuit and sets the exposure sensitivity corresponding to the contents of the most recent instruction issued via the sensitivity setting operation member, indicated in the information stored in the storage device, as the exposure sensitivity at the imaging device, in response to the first instruction received when the second arithmetic operation circuit is selected and engagement of the second control circuit is not allowed. 
     According to a 10th aspect of the present invention, the electronic camera according to the 2nd aspect may further includes a storage device in which information indicating the exposure sensitivity having been set most recently with the first arithmetic operation circuit selected and information indicating contents of an instruction having been most recently issued via the sensitivity setting operation member with the second arithmetic operation circuit is selected are stored. It may be possible that (1) the third control circuit selects the second arithmetic operation circuit instead of the first arithmetic operation circuit and allows engagement of the second control circuit if information indicating the third instruction is stored in the storage device, in response to the first instruction received when the first arithmetic operation circuit is selected; (2) the third control circuit selects the second arithmetic operation circuit instead of the first arithmetic operation circuit and sets one of the most recent exposure sensitivity indicated in the information stored in the storage device and exposure sensitivity corresponding to the contents of the most recent instruction issued via the sensitivity setting operation member and indicated in the information stored in the storage device, as the exposure sensitivity at the imaging device if information indicating the third instruction is not stored in the storage device, in response to the first instruction received when the first arithmetic operation circuit is selected and engagement of the first control circuit is allowed; and (3) the third control circuit selects the second arithmetic operation circuit instead of the first arithmetic operation circuit and sets the most recent exposure sensitivity indicated in the information stored in the storage device as the exposure sensitivity at the imaging device if information indicating the third instruction is not stored in the storage device, in response to the first instruction received when the first arithmetic operation circuit is selected and engagement of the first control circuit is not allowed. 
     An exposure control method for an electronic camera according to a 11th aspect of the present invention: captures a subject image through a photographic lens with an imaging device; detects subject luminance with a luminance detection device; performs a first arithmetic operation that executes exposure calculation by using at least exposure sensitivity set at the imaging device and the subject luminance detected by the luminance detection device among the exposure sensitivity set at the imaging device, an exposure time period set at the imaging device, an aperture value set at the photographic lens and the subject luminance detected by the luminance detection device and determines through arithmetic operation a first control exposure by adjusting at least one of the exposure time period and the aperture value so as to achieve optimal exposure if the optimal exposure is not achieved through the initial exposure calculation, performs a second arithmetic operation that determines through arithmetic operation a second control exposure with regard to the aperture value and the exposure time period so as to achieve the optimal exposure in correspondence to the exposure sensitivity set at the imaging device and the subject luminance detected by the luminance detection device; performs a first control that controls the first arithmetic operation to execute the exposure calculation again by adjusting the exposure sensitivity if calculation results provided by the first arithmetic operation do not achieve the optimal exposure; performs a second control that sets the exposure sensitivity at the imaging device in correspondence to the subject luminance detected by the luminance detection device; and performs a third control that individually controls the first arithmetic operation, the second arithmetic operation, the first control and the second control such that one of the first arithmetic operation and the second arithmetic operation is selected in response to a first instruction, that engagement of the second control is disallowed and engagement of the first control is allowed in response to a second instruction when the first arithmetic operation is selected and that engagement of the first control is disallowed and engagement of the second control is allowed in response to a third instruction when the second arithmetic operation is selected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing the structure adopted in an electronic camera achieved in an embodiment of the present invention: 
         FIG. 2  shows contents of a display brought up at a display device; 
         FIGS. 3A and 3B  present examples of settings that may be selected in response to imaging sensitivity adjustment instructions, with  FIG. 3A  showing settings that may be selected when an “Auto” mode is set for the photographing mode and  FIG. 3B  showing the settings that may be selected when an “A” mode is set for the photographing mode; 
         FIG. 4  presents a flowchart of the main processing executed in an arithmetic operation circuit; 
         FIG. 5  presents a flowchart of the settings processing executed in the arithmetic operation circuit; 
         FIG. 6  presents a flowchart of the settings processing executed in the arithmetic operation circuit; 
         FIG. 7  presents a flowchart of the settings processing executed in the arithmetic operation circuit; 
         FIG. 8  presents a flowchart of the settings processing executed in the arithmetic operation circuit; 
         FIG. 9  presents a flowchart of the sensitivity display processing executed in the arithmetic operation circuit; 
         FIG. 10  presents a flowchart of the exposure calculation processing executed in the arithmetic operation circuit; 
         FIG. 11  presents a flowchart of the exposure calculation processing executed in the arithmetic operation circuit; 
         FIG. 12  presents a flowchart of the exposure calculation processing executed in the arithmetic operation circuit; 
         FIG. 13  presents a flowchart of the display processing executed in the arithmetic operation circuit; 
         FIG. 14  presents a flowchart of the imaging sequence processing executed in the arithmetic operation circuit; 
         FIGS. 15A˜15C  present display examples that may be brought up at the display device; 
         FIGS. 16A and 16B  present display examples that may be brought up at the display device; 
         FIGS. 17A˜17D  present display examples that may be brought up at the display device; 
         FIG. 18  presents a flowchart of a variation of the settings processing executed in the arithmetic operation circuit; 
         FIG. 19  presents a flowchart of a variation of the settings processing executed in the arithmetic operation circuit: 
         FIG. 20  presents an example of a variation of settings that may be selected in response to imaging sensitivity adjustment instructions when the “auto mode” is set for the photographing mode; 
         FIG. 21  presents a flowchart of a variation of the settings processing executed in the arithmetic operation circuit; and 
         FIG. 22  presents a flowchart of a variation of the settings processing executed in the arithmetic operation circuit. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following is an explanation of the best mode for carrying out the present invention given in reference to the drawings.  FIG. 1  is a block diagram showing the structure adopted in an electronic camera achieved in an embodiment of the present invention. An arithmetic operation circuit  101  in  FIG. 1  is constituted with a microcomputer and the like. The arithmetic operation circuit  101  executes a specific arithmetic operation based upon signals input thereto from various blocks to be detailed later and outputs control signals to the individual blocks based upon the results of the arithmetic operation. An image sensor  121  is constituted with a CCD image sensor or the like. The image sensor  121  captures an image formed with subject light having passed through a photographic lens L and outputs image signals to an A/D conversion circuit  122 . 
     The A/D conversion circuit  122  converts analog image signals to digital signals. The drive of the image sensor  121  and the A/D conversion circuit  122  is controlled with predetermined operation timing based upon a drive signal output from a timing circuit  124 . 
     The image sensor  121  is structured so as to allow the imaging sensitivity (exposure sensitivity) to be adjusted within a predetermined range. The term “imaging sensitivity” is used to refer to the sensitivity with which electrical charges stored at the image sensor  121  are detected or the extent of control by which the amplification gain at an amplifier circuit (not shown) is altered. The imaging sensitivity is indicated by the corresponding ISO sensitivity value. In the embodiment, the imaging sensitivity can be set within a range that includes imaging sensitivity levels equivalent to ISO  100 ˜ISO  1600 , imaging sensitivity level “HI-1” higher than the level equivalent to ISO  1600  and an imaging sensitivity level “HI-2” higher than the “ HI-1” level. 
     An ASIC  123  constituting an image signal processing circuit executes a specific type of signal processing on the image signals resulting from the digital conversion in response to an instruction issued by the arithmetic operation circuit  101 . The signal processing executed by the ASIC includes image processing such as white balance (WB) adjustment executed to optimize the color temperature of the color image data, compression processing for compressing image data resulting from the image processing into a predetermined format and decompression processing for decompressing data having undergone the compression processing. Image data currently undergoing the signal processing at the ASIC  123  and image data yet to undergo signal processing or having undergone signal processing are temporarily stored into a buffer memory  125 . A recording medium  126  is constituted with a detachable flash memory or the like. The image data stored in the buffer memory  125  are recorded into the recording medium  126 . 
     A photo metering device  102  detects the quantity of light having been transmitted through the photographic lens L and outputs a light quantity detection signal to the arithmetic operation circuit  101 . The light quantity detection signal indicates the brightness in the photographic field. A shutter control circuit  103  individually controls the hold on and the release of a front curtain and a rear curtain (not shown) at a shutter  104 . An aperture position detection device  107  detects the position of an aperture having been driven to a specific aperture position via a sequence device to be detailed later and outputs an aperture position detection signal to the arithmetic operation circuit  101 . An aperture engaging device  108  engages the aperture being driven so as to stop the aperture at a position corresponding to a specific aperture value. 
     A motor control circuit  105  controls the drive of a sequence motor  106  in response to an instruction issued by the arithmetic operation circuit  101 . The sequence motor  106 , constituting a sequence drive device for controlling the imaging sequence (not shown), raises/lowers a mirror (not shown), drives the aperture (not shown), charges the shutter  104  and the like. A sequence switch SW 1  built in to the sequence drive device (not shown) generates brake control timing for the sequence motor  106  and the like. 
     At a display device  109 , a display indicating the exposure mode, the shutter speed, the aperture value, the number of photographic frames available for photographing, the imaging sensitivity and the like is brought up in response to an instruction issued by the arithmetic operation circuit  101 .  FIG. 2  shows the contents of the display brought up at the display device  109 . “ISO” is displayed at a segment  201  and “Auto” is displayed at a segment  202 . At a segment group  203  a row of four display elements each made of seven segments (appears as 8888 in the figure) to display four digits, the imaging sensitivity is indicated when setting the imaging sensitivity but the shutter speed is indicated at other times. 
     At a segment at which “F” is displayed and a segment group  204  a row of two display elements each made of seven segments (appears as 88 in the figure) to display two digits, the aperture value is indicated. At a segment  205 , a display indicating that an “auto mode” is currently selected for the photographing mode is brought up. The “auto mode” is a photographing mode in which the electronic camera automatically selects settings related to exposure (except for the imaging sensitivity). 
     “A” displayed at a segment  206  indicates that an “A mode” is selected for the photographing mode. The “A mode” is a photographing mode (automatic exposure mode—aperture priority) in which the electronic camera automatically selects the settings related to exposure by using the current aperture value setting. At a segment group  207  a row of three display elements each made of seven segments (appears as 888 in the figure) to display three digits, within the set of “[ ]” a display indicating the number of remaining frames is brought up. 
     A shutter release switch SW 2  enters an ON state by interlocking with depression of a shutter release button (not shown) and enters an OFF state by interlocking with a release of the depressed shutter release button. An ON signal from the shutter release switch SW 2  is input to the arithmetic operation circuit  101  where it is used as a photographing start instruction. 
     Command dial switches SW 6  and SW 7  are turned ON/OFF by interlocking with a rotating operation at a command dial (not shown). The arithmetic operation circuit  101  detects the extent to which the command dial is rotated based upon the number of times, the signals from the switches SW 6  and SW 7  are turned ON/OFF and detects the rotating direction based upon the relationship between the phases of the signals from the switches SW 6  and SW 7 . 
     A photographing mode switch SW 3  enters an ON state by interlocking with a depression of a photographing mode button (not shown) and enters an OFF state by interlocking with a release of the depressed photographing mode button. As operation signals from the command dial switches SW 6  and SW 7  are input while an ON signal from the photographing mode switch SW 3  is input to the arithmetic operation circuit  101 , the arithmetic operation circuit  101  uses these operation signals as a photographing mode adjustment instruction and changes the photographing mode setting to the “auto mode” or the “A mode”. 
     An imaging sensitivity switch SW 4  enters an ON state by interlocking with a depression of an imaging sensitivity button (not shown) and enters an OFF state by interlocking with a release of the depressed imaging sensitivity button. As operation signals from the command dial switches SW 6  and SW 7  are input while an ON signal from the imaging sensitivity switch SW 4  is input to the arithmetic operation circuit  101 , the arithmetic operation circuit  101  uses these operation signals as an imaging sensitivity adjustment instruction. Each time an imaging sensitivity adjustment instruction is issued in the electronic camera set in the “auto mode”, the electronic camera sequentially switches the imaging sensitivity in the order of, for instance, “Auto”-“ISO 100”-“ISO 200”-“ISO 400”-“ISO 800”-“ISO 1600”-“HI-1”-“HI-2”-“Auto” . . . as shown in  FIG. 3A . “Auto” indicates that “imaging sensitivity auto setting” is on, and when the “imaging sensitivity auto setting” is on, the electronic camera automatically determines the imaging sensitivity regardless of the current imaging sensitivity setting. 
     In addition, each time an imaging sensitivity adjustment instruction is issued in the electronic camera set in the “A mode”, the electronic camera sequentially switches the imaging sensitivity in the order of, for instance, “ISO 100”-“ISO 200”-“ISO 400”-“ISO 800”-“ISO 1600”-“HI-1”-“HI-2”-“ISO 100” . . . as shown in  FIG. 3B . The “Auto” setting is not selected in the “A mode” since the “imaging sensitivity auto setting” cannot be turned on in the A mode. 
     A sensitivity auto control switch SW 5  enters an ON state by interlocking with a depression of a sensitivity auto control mode button (not shown) and enters an OFF state by interlocking with a release of the depressed sensitivity auto control mode button. As operation signals from the command dial switches SW 6  and SW 7  are input while an ON signal from the imaging sensitivity auto control mode switch SW 5  is input to the arithmetic operation circuit  101 , the arithmetic operation circuit  101  uses these operation signals as instructions for setting/clearing the “sensitivity auto control mode” and for setting the upper limit for the imaging sensitivity adjustment. 
     The term “sensitivity auto control” is used to refer to control under which exposure calculation is executed based upon the current imaging sensitivity setting selected at the electronic camera and the subject luminance having been calculated and if optimal exposure cannot be achieved through the initial exposure calculation, exposure calculation is executed again by automatically adjusting the imaging sensitivity. It is to be noted that the “sensitivity auto control mode” can be set or cleared only when the “A mode” is set as the photographing mode. When the “auto mode” is set as the photographing mode, control in the “sensitivity auto control mode” is disallowed. 
     The arithmetic operation circuit  101  uses operation signals input thereto from the command dial switches SW 6  and SW 7  as an aperture value adjustment instruction while no operation signal is input from the photographing mode switch SW 3 , the imaging sensitivity switch SW 4  or the sensitivity auto control mode switch SW 5 . In this case, the electronic camera adjusts the aperture setting within a range of F 2.8 to F 22 in accordance with a predetermined procedure in response to the aperture value adjustment instruction. 
     (Main Processing) 
     The camera operation processing executed at the arithmetic operation circuit  101  of the electronic camera is now explained in reference to the flowchart presented in  FIG. 4 . The program that enables the processing shown in the flowchart in  FIG. 4  is started up as a battery (not shown) is loaded into the electronic camera. 
     In step S 1  in  FIG. 4 , the arithmetic operation circuit  101  selects initial settings as detailed below. Namely, it sets a photographing mode flag M to 0, a sensitivity auto setting mode flag A to 1, a sensitivity auto control mode flag S to 0, an imaging sensitivity setting SVs to 5 (ISO  100 ) and a sensitivity storage parameter SVo to 5, and then the operation proceeds to step S 2 . It is to be noted that an apex value is selected for SVs. 
     The photographing mode flag M is set to 0 when the “auto mode” is selected for the photographing mode and is set to  1  when the “A mode” is selected for the photographing mode. The sensitivity auto setting mode flag A is set to 1 when the “imaging sensitivity auto setting” is turned on and is set to 0 when the “imaging sensitivity auto setting” is turned off. The sensitivity auto control mode flag S is set to 1 when the “sensitivity auto control mode” is selected and is set to 0 when the “sensitivity auto control mode” is cleared. The sensitivity storage parameter SVo is a parameter used to store details of the adjusted setting selected in response to an imaging sensitivity adjustment instruction. 
     In step S 2 , the arithmetic operation circuit  101  executes settings processing and then the operation proceeds to step S 3 . The settings processing is to be described in detail later. In step S 3 , the arithmetic operation circuit  101  determines through arithmetic operation the quantity (BV-AV 0 ) of light having been transmitted through the lens based upon the detection signal input from the photometering device  102  and executes a photometering operation for determining the subject luminance BV by using the light quantity value having been determined through the arithmetic operation. Then the operation proceeds to step S 4 . The subject luminance BV can be calculated by adding an open aperture value AV 0  to the quantity (BV-AV 0 ) of the light having been transmitted through that lens. It is to be noted that AV 0 =3, i.e., F2.8, in the embodiment. It is also to be noted that BV and AV 0  (3 in the example explained above) each assumes an apex value. 
     In step S 4 , the arithmetic operation circuit  101  executes exposure calculation processing before the operation proceeds to step S 5 . The exposure calculation processing is to be described in detail later. In step S 5 , the arithmetic operation circuit  101  calculates the number of remaining frames indicating the number of images that can still be recorded into the recording medium  126 , and then the operation proceeds to step S 6 . In step S 6 , the arithmetic operation circuit  101  executes display processing for the display device  109  before the operation proceeds to step S 7 . The display processing is to be described in detail later. 
     In step S 7 , the arithmetic operation circuit  101  makes a decision as to whether or not a shutter release operation has been performed. The arithmetic operation circuit  101  makes an affirmative decision in step S 7  if an ON signal has been input from the shutter release switch SW 2  and in this case, the operation proceeds to step S 8 . If, on the other hand, an ON signal has not been input from the shutter release switch SW 2 , the arithmetic operation circuit  101  makes a negative decision in step S 7 , and the operation returns to step S 2 . 
     In step S 8 , the arithmetic operation circuit  101  executes imaging sequence processing, and then the operation returns to step S 2 . The imaging sequence processing is to be described in detail later. The sequence of photographing processing thus ends. 
     (Settings Processing) 
     The settings processing executed in step S 2  is now explained in detail in reference to the flowchart presented in  FIGS. 5  through B. In step S 101  in  FIG. 5 , the arithmetic operation circuit  101  makes a decision as to whether or not the imaging sensitivity button is currently depressed. The arithmetic operation circuit  101  makes an affirmative decision in step S 101  if an ON signal has been input from the imaging sensitivity switch SW 4  and, in this case, the operation proceeds to step S 102 . If, on the other hand, an ON signal has not been input from the imaging sensitivity switch SW 4 , it makes a negative decision in step S 101  and, in this case, the operation proceeds to step S 141  in  FIG. 7 . 
     In step S 102 , the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag M is currently set to 0. If M=0 (auto mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 102  to proceed to step S 103 , whereas if M≠0 (i.e., if the A mode is currently selected in this example), it makes a negative decision in step S 102  to proceed to step S 123  in  FIG. 6 . 
     In step S 103 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto setting mode flag A is currently set to 1. If A=1 (if the imaging sensitivity auto setting is ON), the arithmetic operation circuit  101  makes an affirmative decision in step S 103  to proceed to step S 104 , whereas if A≠1 (i.e., if the imaging sensitivity auto setting is OFF), it makes a negative decision in step S 103  to proceed to step S 111 . 
     In step S 104 , the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated upward. If operation signals indicating a counterclockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 104  to proceed to step S 105 , whereas if operation signals indicating a counterclockwise rotation have not been input, it makes a negative decision in step S 104  to proceed to step S 108 . 
     In step S 105 , the arithmetic operation circuit  101  sets 5 (ISO  100 ) for the imaging sensitivity setting SVs, and then the operation proceeds to step S 106 . In step S 106 , the arithmetic operation circuit  101  sets the sensitivity auto setting mode flag A to 0 before the operation proceeds to step S 107 . As described above, the ON status of the “imaging sensitivity auto setting” is canceled in response to an upward rotation of the command dial so as to allow imaging sensitivity to be adjusted, starting at “ISO 100” in the embodiment. 
     In step S 107 , the arithmetic operation circuit  101  executes sensitivity display processing, before the operation returns to step S 101 . The sensitivity display processing is to be described in detail later. 
     In step S 108 , to which the operation proceeds after making a negative decision in step S 104  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated downward. If operation signals indicating a clockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 108  to proceed to step S 109 , whereas if operation signals indicating a clockwise rotation have not been input, it makes a negative decision in step S 108  to proceed to step S 107 . 
     In step S 109 , the arithmetic operation circuit  101  sets 11 (HI-2 explained earlier) for the imaging sensitivity setting SVs, and then the operation proceeds to step S 110  In step S 110 , the arithmetic operation circuit  101  sets the sensitivity auto setting mode flag A to 0 before the operation proceeds to step S 107 . As described above, the ON status of the “imaging sensitivity auto setting” is canceled in response to a downward rotation of the command dial so as to allow the imaging sensitivity to be adjusted, starting at “HI-2” in the embodiment. 
     In step S 111 , to which the operation proceeds after making a negative decision in step S 103  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated upward. If operation signals indicating a counterclockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 111  to proceed to step S 112 , whereas if operation signals indicating a counterclockwise rotation have not been input, it makes a negative decision in step S 111  to proceed to step S 115 . 
     In step S 112 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 11. If SVs=11 (HI-2), the arithmetic operation circuit  101  makes an affirmative decision in step S 112  to proceed to step S 113 , whereas if SVs≠11, it makes a negative decision in step S 112  to proceed to step S 114 . In step S 113 , the arithmetic operation circuit  101  sets the sensitivity auto setting mode flag A to 1 and then the operation proceeds to step S 107 . As described above, the “imaging sensitivity auto setting” enters an ON state as the command dial is rotated upward while the current imaging sensitivity setting is “HI-2” in the embodiment, 
     In step S 114 , the arithmetic operation circuit  101  increments the value set for the imaging sensitivity setting SVs by 1, and then the operation proceeds to step S 107 . As a result, the imaging sensitivity setting SVs is adjusted to a level higher by one step. 
     In step S 115 , to which the operation proceeds after making a negative decision in step S 111  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated downward. If operation signals indicating a clockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 115  to proceed to step S 116 , whereas if operation signals indicating a clockwise rotation have not been input, it makes a negative decision in step S 115  to proceed to step S 107 . 
     In step S 116 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 5. If SVs=5 (ISO  100 ), the arithmetic operation circuit  101  makes an affirmative decision in step S 116  to proceed to step S 117 , whereas if SVs≠5, it makes a negative decision in step S 116  to proceed to step S 118 . In step S 117 , the arithmetic operation circuit  101  sets the sensitivity auto setting mode flag A to 1 and then the operation proceeds to step S 107 . As described above, the “imaging sensitivity auto setting” enters an ON state as the command dial is rotated downward while the current imaging sensitivity setting is “ISO 100” in the embodiment. 
     In step S 118 , the arithmetic operation circuit  101  decrements the value set for the imaging sensitivity setting SVs by 1, and then the operation proceeds to step S 107 . As a result, the imaging sensitivity setting SVs is adjusted to a level lower by one step. 
     In step S 123  in  FIG. 6 , to which the operation proceeds after making a negative decision in step S 102  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated upward. If operation signals indicating a counterclockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 123  to proceed to step S 124 , whereas if operation signals indicating a counterclockwise rotation have not been input, it makes a negative decision in step S 123  to proceed to step S 128 . 
     In step S 124 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 11. If SVs=11 (HI-2), the arithmetic operation circuit  101  makes an affirmative decision in step S 124  to proceed to step S 125 , whereas if SVs≠11, it makes a negative decision in step S 124  to proceed to step S 126 . In step S 125 , the arithmetic operation circuit  101  sets 5 (ISO  100 ) for the imaging sensitivity setting SVs and then the operation proceeds to step S 127 . 
     In step S 127 , the arithmetic operation circuit  101  increments the value set for the imaging sensitivity setting SVs by 1, and then the operation proceeds to step S 127 . As a result, the imaging sensitivity setting SVs is adjusted to a level higher by one step. 
     In step S 128 , to which the operation proceeds after making a negative decision in step S 123  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial is being rotated downward. If operation signals indicating a clockwise rotation have been input from the command dial switches SW 6  and SW 7 , the arithmetic operation circuit  101  makes an affirmative decision in step S 128  to proceed to step S 129 , whereas if operation signals indicating a clockwise rotation have not been input, it makes a negative decision in step S 12 B to proceed to step S 127 . 
     In step S 129 , the arithmetic operation circuit  101  makes a decision as to whether or not the current imaging sensitivity setting SVs is 5. If SVs=5 (ISO  100 ), the arithmetic operation circuit  101  makes an affirmative decision in step S 129  to proceed to step S 130 , whereas if SVs≠5, it makes a negative decision in step S 129  to proceed to step S 131 . 
     In step S 130 , the arithmetic operation circuit  101  sets 11 (HI-2) for the imaging sensitivity setting SVs and then the operation proceeds to step S 127 . In step S 131 , the arithmetic operation circuit  101  decrements the value set for the imaging sensitivity setting SVs by 1, and then the operation proceeds to step S 127 . As a result, the imaging sensitivity setting SVs is adjusted to a level lower by one step. 
     In step S 127 , the arithmetic operation circuit  101  sets the value having been selected as the imaging sensitivity setting SVs for the sensitivity storage parameter SVo, and then the operation proceeds to step S 107  in  FIG. 5 . As a result, the imaging sensitivity SVs having been selected in the “A mode” is stored as the sensitivity storage parameter SVo. 
     In step S 141  in  FIG. 7 , to which the operation proceeds after making a negative decision in step S 101  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode button has been depressed. The arithmetic operation circuit  101  makes an affirmative decision in step S 141  if an operation signal has been input from the photographing mode switch SW 3  to proceed to step  3142 , whereas it makes a negative decision in step S 141  if no operation signal has been input from the photographing mode switch SW 3  and, in this case, the operation proceeds to step S 147 . 
     Instep S 142 , the arithmetic operation circuit  101  makes a decision as to whether or not the command dial has been rotated. The arithmetic operation circuit  101  makes an affirmative decision in step S 142  if operation signals have been input from the command dial switches SW 6  and SW 7  to proceed to step S 143 , whereas it makes a negative decision in step S 142  if no operation signals have been input to proceed to step S 146 . 
     In step S 143 , the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag M is currently set to 0. If M=0 (auto mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 143  to proceed to step S 144 , whereas if M≠0 (i.e., if the A mode is currently selected in this example), it makes a negative decision in step S 143  to proceed to step S 145 . 
     In step S 144 , the arithmetic operation circuit  101  sets the photographing mode flag M to 1, i.e., sets the “A mode” for the photographing mode, and then the operation proceeds to step S 144 A. In step S 145 , the arithmetic operation circuit  101  sets the photographing mode flag M to 0, i.e., sets the “auto mode” for the photographing mode, and then the operation proceeds to step S 146 . In step S 144 A, the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto setting mode flag A is currently set to 1 if A=1 (if the imaging sensitivity auto setting is ON), the arithmetic operation circuit  101  makes an affirmative decision in step S 144 A to proceed to step S 144 A, whereas if A≠1 (i.e., if the imaging sensitivity auto setting is OFF), it makes a negative decision in step S 144 A to proceed to step S 146 . 
     In step S 144 B, the arithmetic operation circuit  101  sets the value stored as the sensitivity storage parameter SVo as the imaging sensitivity setting SVs before the operation proceeds to step S 146 . Thus, as the photographing mode is switched from the “auto mode” to the “A mode” while the “imaging sensitivity auto setting” is on, the sensitivity value having been selected for the most recent “A mode” operation is set as SVs. In step S 146 , the arithmetic operation circuit  101  issues an instruction for the display device  109  to bring up a display indicating the photographing mode, and then the operation returns to step S 141 . 
       FIGS. 16A and 16B  present examples of displays that may be provided via the display device  109 . The display in  FIG. 16A , which is brought up while the photographing mode button is depressed, indicates that the “auto mode” has been selected for the photographing mode, with the segment  205  indicating the “auto mode” in an ON state.  FIG. 16B , which is also brought up while the photographing mode button is depressed, indicates that the “A mode” has been selected for the photographing mode with the segment  206  indicating the “A mode” in an ON state. 
     In step S 147 , to which the operation proceeds after making a negative decision in step S 141  in  FIG. 7  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag M is currently set to 1. If M=1 (A mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 147  to proceed to step S 148 , whereas if M≠1 (i.e., if the auto mode is currently selected in this example), it makes a negative decision in step S 147  to proceed to step S 171  in  FIG. 8 . 
     Instep S 148 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto control mode button has been depressed. The arithmetic operation circuit  101  makes an affirmative decision in step S 148  if an operation signal has been input from the sensitivity auto control mode switch SW 5  to proceed to step S 149 , whereas it makes a negative decision in step S 148  if no operation signal has been input from the sensitivity auto control mode switch SW 5  to proceed to step S 171  in  FIG. 8 . 
     Instep S 149 , the arithmetic operation circuit  101  makes a decision as to whether or not the command dial has been rotated along the counterclockwise direction. The arithmetic operation circuit  101  makes an affirmative decision in step S 149  if operation signals indicating a counterclockwise rotation have been input from the command dial switches SW 6  and SW 7  to proceed to step S 150 , whereas it makes a negative decision in step S 149  if no operation signals indicating a counterclockwise rotation have been input and, in this case, the operation proceeds to step S 156 . 
     Instep S 150 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto control mode flag S is currently set to 0. If S=0 (if the sensitivity auto control mode has been cleared), the arithmetic operation circuit  101  makes an affirmative decision in step S 150  to proceed to step S 151 , whereas if S≠0 (i.e., if the sensitivity auto control mode is currently selected in this case) it makes a negative decision in step S 150  to proceed to step S 153 . 
     In step S 151 , the arithmetic operation circuit  101  sets the sensitivity auto control mode flag S to 1, i.e., selects the “sensitivity auto control mode”, and also sets 7 (ISO  400 ) as the sensitivity adjustment upper limit Su, before the operation proceeds to step S 152 . In step S 153 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity adjustment upper limit Su is equal to 9. If Su=9 (ISO  1600 ), the arithmetic operation circuit  101  makes an affirmative decision in step S 153  to proceed to step S 155 , whereas if Su≠9, it makes a negative decision in step S 153  to proceed to step S 154 . 
     In step S 154 , the arithmetic operation circuit  101  increments the value set for the sensitivity adjustment upper limit Su by one, and then the operation proceeds to step S 152 . As a result, the imaging sensitivity adjustment upper limit Su is raised by one step. In step S 155 , the arithmetic operation circuit  101  sets the sensitivity auto control mode flag S to 0, i.e., clears the “sensitivity auto control mode”, before the operation proceeds to step S 152 . 
     In step S 156 , to which the operation proceeds after making a negative decision in step S 149  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial has been rotated along the clockwise direction. The arithmetic operation circuit  101  makes an affirmative decision in step S 156  if operation signals indicating a clockwise rotation have been input from the command dial switches SW 6  and SW 7  to proceed to step S 157 , whereas it makes a negative decision in step S 156  if no operation signals indicating a clockwise rotation have been input and, in this case, the operation proceeds to step S 152 . 
     In step S 157 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto control mode flag S is currently set to 0. If S=0 (if the sensitivity auto control mode has been cleared), the arithmetic operation circuit  101  makes an affirmative decision in step S 157  to proceed to step S 158 , whereas if S≠0 (i.e., if the sensitivity auto control mode is currently selected in this case) it makes a negative decision in step S 157  to proceed to step S 159 . 
     In step S 158 , the arithmetic operation circuit  101  sets the sensitivity auto control mode flag S to 1, i.e., selects the “sensitivity auto control mode”, and also sets 9 (ISO  1600 ) as the sensitivity adjustment upper limit Su, before the operation proceeds to step S 152 . In step S 159 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity adjustment upper limit Su is equal to 7. If Su=7 (ISO  400 ), the arithmetic operation circuit  101  makes an affirmative decision in step S 159  to proceed to step S 161 , whereas if Su≠7, it makes a negative decision in step S 159  to proceed to step S 160 . 
     In step S 160 , the arithmetic operation circuit  101  decrements the value set for the sensitivity adjustment upper limit Su by one, and then the operation proceeds to step S 152 . As a result, the imaging sensitivity adjustment upper limit Su is lowered by one step In step S 161 , the arithmetic operation circuit  101  sets the sensitivity auto control mode flag S to 0, i.e., clears the “sensitivity auto control mode”, before the operation proceeds to step S 152 . 
     In step S 152 , the arithmetic operation circuit  161  makes a decision as to whether or not the sensitivity auto control mode flags is currently set to 1. If S=1 (if the sensitivity auto control mode is currently selected), the arithmetic operation circuit  101  makes an affirmative decision in step S 152  to proceed to step S 162 , whereas if S=0 (i.e., if the sensitivity auto control mode has been cleared) makes a negative decision in step S 152  to proceed to step S 163 . In step S 162 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “ISO” and “Auto” respectively at the segment  201  and the segment  202 , and then the operation returns to step S 148 . In step S 163 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “ISO” at the segment  201 , before the operation returns to step S 148 . 
       FIGS. 17A˜17D  presents examples of displays that may be brought up at the display device  109 .  FIG. 17A  shows an example of a display brought up while the sensitivity auto control mode button is depressed, to indicate that the “A mode” is selected for the photographing mode and that the “sensitivity auto control mode” has been cleared, with the segment  201  alone in an ON state.  FIGS. 17B through 17D  each show an example of a display brought up while the sensitivity auto control mode button is depressed, to indicate that the “A mode” has been selected for the photographing mode and that the “sensitivity auto control mode” has also been set.  FIGS. 17B˜17D  each show that the segment  201  and the segment  202  are in an ON state with the value indicating the imaging sensitivity adjustment upper limit Su displayed at the segment group  203 . “Auto” at the segment  202  indicates that the “sensitivity auto control mode” has been selected. 
     In step S 171  in  FIG. 8 , to which the operation proceeds after making a negative decision in step S 147  or step S 148  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial has been rotated along the counterclockwise direction. The arithmetic operation circuit  101  makes an affirmative decision in step S 171  if operation signals indicating a counterclockwise rotation have been input from the command dial switches SW 6  and SW 7  to proceed to step S 172 , whereas it makes a negative decision in step S 171  if no operation signals indicating a counterclockwise rotation have been input and, in this case, the operation proceeds to step S 175 . 
     In step S 172 , the arithmetic operation circuit  101  makes a decision as to whether or not 9 (F 22) has been selected for the aperture setting AVs. If AVs=9, the arithmetic operation circuit  101  makes an affirmative decision in step S 172  to proceed to step S 174 , whereas if AVs≠9, it makes a negative decision in step S 172  to proceed to step S 173 . In step S 173 , the arithmetic operation circuit  101  increments the value set for the aperture setting AVs by one, and then the operation proceeds to step S 174 . As a result, the aperture value setting is adjusted to a level higher by one step. 
     In step S 175 , to which the operation proceeds after making a negative decision in step S 171  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the command dial has been rotated along the clockwise direction. The arithmetic operation circuit  101  makes an affirmative decision in step S 175  if operation signals indicating a clockwise rotation have been input from the command dial switches SW 6  and SW 7  to proceed to step S 176 , whereas it makes a negative decision in step S 175  if no operation signals indicating a clockwise rotation have been input, and in this case, the processing in  FIGS. 5 through 8  ends. 
     In step S 176 , the arithmetic operation circuit  101  makes a decision as to whether or not 3 (F 2.8) has been selected for the aperture setting AVs. If AVs=3, the arithmetic operation circuit  101  makes an affirmative decision in step S 176  to proceed to step S 174 , whereas if AVs≠3, it makes a negative decision in step S 176  to proceed to step S 177 . In step S 177 , the arithmetic operation circuit  101  decrements the value set for the aperture setting AVs by one, and then the operation proceeds to step S 174 . As a result, the aperture value setting is adjusted to a level lower by one step. 
     In step S 174 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to update the aperture value display at the segment group  204 , and then, the processing in  FIGS. 5 through 8  ends. 
     (Sensitivity Display Processing) 
     The sensitivity display processing executed in step S 107  in  FIG. 5  is now described in detail in reference to the flowchart presented in  FIG. 9 . In step S 181  in  FIG. 9 , the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag M is currently set to 0. If M=0 (auto mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 181  to proceed to step S 182 , whereas if M≠0 (i.e., if the A mode is currently selected in this example), it makes a negative decision in step S 181  to proceed to step S 185 . 
     In step S 182 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto setting mode flag A is currently set to 1. If A=1 (if the imaging sensitivity auto setting is ON), the arithmetic operation circuit  101  makes an affirmative decision in step S 182  to proceed to step S 183 , whereas if A≠1 (i.e., if the imaging sensitivity auto setting is OFF), it makes a negative decision in step S 182  to proceed to step S 185 . 
     In step S 183 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “Auto” at the segment  203 , before the operation proceeds to step S 184 . In step S 185 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 5 (ISO  100 ). If SVs=5, the arithmetic operation circuit  101  makes an affirmative decision in step S 185  to proceed to step S 186 , whereas if SVs≠5, it makes a negative decision in step S 185  to proceed to step S 187 . In step S 186 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “100” at the segment group  203  and then the operation proceeds to step S 184 . 
     Instep S 187 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 6 (ISO  200 ). If SVs=6, the arithmetic operation circuit  101  makes an affirmative decision in step S 187  to proceed to step S 188 , whereas if SVs≠6, it makes a negative decision in step S 187  to proceed to step S 189 . In step S 188 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “200” at the segment group  203  and then the operation proceeds to step S 184 . 
     Instep S 189 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 7 (ISO  400 ). If SVs=7, the arithmetic operation circuit  101  makes an affirmative decision in step S 189  to proceed to step S 190 , whereas if SVs≠7, it makes a negative decision in step S 189  to proceed to step S 191 . In step S 190 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “400” at the segment group  203  and then the operation proceeds to step S 184 . 
     In step S 191 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 8 (ISO  800 ). If SVs=8, the arithmetic operation circuit  101  makes an affirmative decision in step S 191  to proceed to step S 192 , whereas if SVs≠8, it makes a negative decision in step S 191  to proceed to step S 193 . In step S 192 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “800” at the segment group  203  and then the operation proceeds to step S 184 . 
     In step S 193 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 9 (ISO  1600 ). If SVs=9, the arithmetic operation circuit  101  makes an affirmative decision in step S 193  to proceed to step S 194 , whereas if SVs≠9, it makes a negative decision in step S 193  to proceed to step S 195 . In step S 194 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “1600” at the segment group  203  and then the operation proceeds to step S 184 . 
     In step S 195 , the arithmetic operation circuit  101  makes a decision as to whether or not SVs is currently set to 10 (HI-1). If SVs=10, the arithmetic operation circuit  101  makes an affirmative decision in step S 195  to proceed to step S 196 , whereas if SVs≠10, it makes a negative decision in step S 195  to proceed to step S 197 . Instep S 196 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “HI-1” at the segment group  203  and then the operation proceeds to step S 184 . In step S 197 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “HI-2” at the segment group  203  and then the operation proceeds to step S 184 . 
     In step S 184 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “ISO” at the segment  201 , and then ends the processing shown in  FIG. 9  before the operation returns to step S 101  in  FIG. 5 . 
       FIGS. 15A˜15C  present examples of displays that may be brought up at the display device  109 . In the display example in  FIG. 15A  brought up while the imaging sensitivity button is depressed, “ISO” and “100” are in an ON state through the processing executed in step S 184  and step S 186 . In  FIG. 15B  presenting another example of display brought up while the imaging sensitivity button is depressed, “ISO” and “HI-1” are in an ON state through the processing executed in step S 184  and step S 196 . In  FIG. 15C  presenting yet another example of display brought up when the imaging sensitivity button is depressed, “ISO” and “Auto” are in an ON state through the processing executed in step S 184  and step S 183 . When “Auto” is in an ON state at the segment  203 , the “imaging sensitivity auto setting” is on. 
     (Exposure Calculation Processing) 
     The exposure calculation processing executed in step S 4  in  FIG. 4  is now explained in detail in reference to the flowchart presented in  FIGS. 10 through 12 . In step S 201  in  FIG. 10 , the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag N is currently set to 1. If M=1 (A mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 201  to proceed to step S 202 , whereas if M≠1 (i.e., if the auto mode is currently selected in this example), it makes a negative decision in step S 201  to proceed to step S 241  in  FIG. 11 . 
     In step S 202 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as EV=BV+SVs by using the subject luminance BV calculated in step S 3 , and then the operation proceeds to step S 203 . EV represents the exposure value. The imaging sensitivity setting SVs is the imaging sensitivity having been set through the settings processing. It is to be noted that EV, BV and SVs are each indicated by using an apex value. 
     In step S 203 , the arithmetic operation circuit  101  sets the aperture value setting AVs as the control aperture value AVc, before the operation proceeds to step S 204 . AVc and AVs are each indicated by using an apex value. In step S 204 , the arithmetic operation circuit  101  calculates a control aperture pulse number Pc indicating the number of control aperture pulses as a function f of the number of aperture setting steps (AVc−3) and then the operation proceeds to step S 205 . The control aperture pulse number Pc indicates the number of detection pulses output from the aperture position detection device  107  before the aperture becomes engaged at the position corresponding to the control aperture value AVc. While the number of aperture setting steps and the number of aperture pulses are in proportion to each other, the control aperture pulse number is calculated as the function f of the number of aperture setting steps (AVc−3), since a great number of aperture detection pulses are output in the vicinity of the open aperture setting. 
     In step S 205 , the arithmetic operation circuit  101  sets the value obtained by subtracting the control aperture value AVc from the exposure value EV as a control shutter speed TVc and then the operation proceeds to step S 206 . TVc is indicated by using an apex value. In step S 206 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto control mode flag S is currently set to 1. The arithmetic operation circuit  101  makes an affirmative decision in step S 206  if S=1 (if the sensitivity auto control mode is currently set) to proceed to step S 215 , whereas it makes a negative decision in step S 206  if S=0 (if the sensitivity auto control mode has been cleared) to proceed to step S 207 . 
     In step S 207 , the arithmetic operation circuit  101  makes a decision as to whether or not TVc&lt;−5 is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 207  if TVc&lt;−5 is true (if the control shutter speed is lower than 30 sec) to proceed to step S 208 , whereas it makes a negative decision in step S 207  if TVc&lt;−5 is not true and, in this case, the operation proceeds to step S 211 . In step S 208 , the arithmetic operation circuit  101  sets −5 for the control shutter speed TVc and then the operation proceeds to step S 209 . As a result, the control shutter speed is set to 30 sec, which is the lower limit of the control range. 
     In step S 211 , the arithmetic operation circuit  101  makes a decision as to whether or not TVc&gt;12 is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 211  if TVc&gt;12 is true (if the control shutter speed is higher than 1/4000 sec) to proceed to step S 212 , whereas it makes a negative decision in step S 211  if TVc&gt;12 is not true and, in this case, the operation proceeds to step S 209 . In step S 212 , the arithmetic operation circuit  101  sets 12 for the control shutter speed TVc and then the operation proceeds to step S 209 . As a result, the control shutter speed is set to 1/4000 sec, which is the upper limit of the control range. 
     In step S 209 , the arithmetic operation circuit  101  sets the current value of the imaging sensitivity setting SVs for the control imaging sensitivity SVc and then the operation proceeds to step S 210 . In step S 210 , the arithmetic operation circuit  101  sets 0 at a flag C, and ends the processing in  FIG. 10 . The operation subsequently proceeds to step  5 S in  FIG. 4 . The flag C is set to 1 when the imaging sensitivity is altered from the imaging sensitivity setting SVs (SVc≠SVs) and is set to D if the imaging sensitivity remains unchanged from the imaging sensitivity setting SVs (SVc=SVs). 
     The processing executed from step S 201  through S 212  as described above corresponds to the exposure calculation executed when the “A mode” is set as the photographing mode and the “sensitivity auto control mode” has been cleared. 
     In step S 215 , to which the operation proceeds after making an affirmative decision in step S 206  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not TVc&lt;5 is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 215  if TVc&lt;5 is true (if the control shutter speed is lower than 1/30 sec) to proceed to step S 216 , whereas it makes a negative decision in step S 215  if TVC&lt;5 is not true and, in this case, the operation proceeds to step S 219 . In step S 216 , the arithmetic operation circuit  101  designates the value obtained by subtracting the control shutter speed TVc from the apex value 5 as ΔTV, before the operation proceeds to step S 217 . 
     In step S 217 , the arithmetic operation circuit  101  sets 5 for the control shutter speed TVc and then the operation proceeds to step S 218 . As a result, the control shutter speed is set to a specific value (i.e., 1/30 sec defined as a shaky hand movement limit in the embodiment). 
     In step S 219 , the arithmetic operation circuit  101  makes a decision as to whether or not TVc&gt;12 is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 219  if TVc&gt;12 is true (if the control shutter speed is higher than 1/4000 sec) to proceed to step S 220 , whereas it makes a negative decision in step S 219  if TVc&gt;12 is not true and, in this case, the operation proceeds to step S 222 . In step S 220 , the arithmetic operation circuit  101  designates the value obtained by subtracting the control shutter speed TVc from the apex value 12 as ΔTV, before the operation proceeds to step S 221 . 
     In step S 221 , the arithmetic operation circuit  101  sets 12 for the control shutter speed TVc before the operation proceeds to step S 218 . Thus, the control shutter speed is set to 1/4000 seconds, which is the upper limit of the control range. In step S 222 , the arithmetic operation circuit  101  sets 0 for ΔTV and then the operation proceeds to step S 218 . 
     In step S 218 , the arithmetic operation circuit  101  sets the value obtained by adding ΔTV to the control imaging sensitivity SVs as a new control imaging sensitivity SVc and then the operation proceeds to step S 223 . In step S 223 , the arithmetic operation circuit  101  makes a decision as to whether or not SVc&gt;Su is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 223  if the control imaging sensitivity SVc is higher than the imaging sensitivity adjustment upper limit Su to proceed to step S 224 , whereas it makes a negative decision in step S 223  if the control imaging sensitivity SVc is not higher than the imaging sensitivity adjustment upper limit Su and, in this case, the operation proceeds to step S 231 . 
     In step S 224 , the arithmetic operation circuit  101  designates the value obtained by subtracting the imaging sensitivity adjustment upper limit Su from the control imaging sensitivity SVc as ΔSV, before the operation proceeds to step S 225 . In step S 225 , the arithmetic operation circuit  101  sets the value indicating the imaging sensitivity adjustment upper limit Su as the control imaging sensitivity SVc and then the operation proceeds to step S 226 . 
     In step S 226 , the arithmetic operation circuit  101  designates the value obtained by subtracting ΔSV from the control shutter speed TVc as a new control shutter speed TVc before the operation proceeds to step S 227 . In step S 227 , the arithmetic operation circuit  101  makes a decision as to whether or not TVc&lt;−5 is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 227  if TVc&lt;−5 is true (if the control shutter speed is lower than 30 sec) to proceed to step S 228 , whereas it makes a negative decision in step S 227  if TVc&lt;−5 is not true and, in this case, the operation proceeds to step S 231 . In step S 228 , the arithmetic operation circuit  101  sets −5 for the control shutter speed TVc and then the operation proceeds to step S 231 . As a result, the control shutter speed is set to 30 sec, which is the lower limit of the control range. 
     In step S 231 , the arithmetic operation circuit  101  makes a decision as to whether or not SVc=SVs is true. The arithmetic operation circuit  101  makes an affirmative decision in step S 231  if SVc=SVs is true to proceed to step S 232 , whereas it makes a negative decision in step S 231  if SVc=SVs is not true to proceed to step S 233 . 
     In step S 232 , the arithmetic operation circuit  101  sets 0 at the flag C, and ends the processing shown in  FIG. 10 , before the operation proceeds to step S 5  in  FIG. 4 . In step S 233 , the arithmetic operation circuit  101  sets 1 at the flag C, and ends the processing shown in  FIG. 10 , before the operation proceeds to step S 5  in  FIG. 4 . 
     The processing executed from step S 215  through S 233  as described above corresponds to the exposure calculation executed when the “A mode” is set as the photographing mode and the “sensitivity auto control mode” has been selected. 
     In step S 241  in  FIG. 11 , to which the operation proceeds after making a negative decision in step S 201  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto setting mode flag A is currently set to 1. If A=1 (if the imaging sensitivity auto setting is on), the arithmetic operation  101  makes an affirmative decision in step  5241  to proceed to step S 261  in  FIG. 12 , whereas if A≠1 (if the imaging&#39;sensitivity auto setting is off), the arithmetic operation circuit makes a negative decision in step S 241  to proceed to step S 242 . 
     In step S 242 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as EV=BV+SVs by using the subject luminance BV having been calculated in step S 3  and then the operation proceeds to step S 243 . In step S 243 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as AVc=EV/2−1 before the operation proceeds to step S 244 . AVc represents the control aperture value. 
     In step S 244 , the arithmetic operation circuit  101  makes a decision as to whether or not the control aperture value AVc is smaller than F 2.8. The arithmetic operation circuit  101  makes an affirmative decision in step S 244  if AVc&lt;3 is true to proceed to step S 245 , whereas it makes a negative decision in step S 244  if AVc&lt;3 is not true and, in this case, the operation proceeds to step S 247 . In step S 245 , the arithmetic operation circuit  101  sets the control aperture value AVc to 3 (F 2.8 corresponding to the open aperture) and then the operation proceeds to step S 246 . 
     In step S 247 , the arithmetic operation circuit  101  makes a decision as to whether or not the control aperture value AVc is greater than F 22. The arithmetic operation circuit  101  makes an affirmative decision in step S 247  if AVc&gt;9 is true to proceed to step S 248 , whereas it makes a negative decision in step S 247  if AVc&gt;9 is not true to proceed to step S 246 . In step S 248 , the arithmetic operation circuit  101  sets the control aperture value AVc to 9 (F 22 corresponding to the smallest aperture) and then the operation proceeds to step S 246 . 
     In step S 246 , the arithmetic operation circuit  101  calculates the control aperture pulse number Pc as the function f of the number of aperture setting steps (AVc−3) and then the operation proceeds to step S 249 . Since the processing executed in steps S 249  through S 254  is identical to the processing executed in steps S 207  through S 212  in  FIG. 10 , its explanation is omitted. 
     The processing executed from stop S 241  through step S 254  as described above corresponds to the exposure calculation executed when the “auto mode” is set for the photographing mode and the imaging sensitivity is selected through user operation. 
     In step S 261  in  FIG. 12 , to which the operation proceeds after making an affirmative decision in step S 241  as described above, the arithmetic operation circuit  101  makes a decision as to whether or not the subject luminance BV is greater than 16. If BV&gt;16 is true, the arithmetic operation circuit  101  makes an affirmative decision in step S 261  to proceed to step S 262 . If, on the other hand, BV&gt;16 is not true, the arithmetic operation circuit makes a negative decision in step S 261  to proceed to step S 263 . In step S 262 , the arithmetic operation circuit  101  sets 16 (control limit) for the luminance BV and then the operation proceeds to step S 263 . 
     In step S 263 , the arithmetic operation circuit  101  makes a decision as to whether or not the subject luminance BV is equal to or greater than 7. If BV≧7 is true, the arithmetic operation circuit  101  makes an affirmative decision in step S 263  to proceed to step S 264 . If, on the other hand, BV≧7 is not true, the arithmetic operation circuit makes a negative decision in step S 263  to proceed to step S 272 . 
     In step S 264 , the arithmetic operation circuit  101  sets the control imaging sensitivity SVc to 5 (ISO  100 ) and then the operation proceeds to step S 265 . In step S 265 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as EV=BV+SVc to determine the exposure value EV, before the operation proceeds to step S 266 . In step S 266 , the arithmetic operation circuit  101  executes in arithmetic operation expressed as AVc=EV/2−1 and then the operation proceeds to step S 267 . 
     Instep S 267 , the arithmetic operation circuit  101  makes a decision as to whether or not the control aperture value AVc is greater than F 22. The arithmetic operation circuit  101  makes an affirmative decision in step S 267  if AVc&gt;9 is true to proceed to step S 268 , whereas it makes a negative decision in step S 267  if AVc&gt;9 is not true and, in this case, the operation proceeds to step S 269 . In step S 268 , the arithmetic operation circuit  101  sets the control aperture value AVc to 9 (F 22 corresponding to the smallest aperture) and then the operation proceeds to step S 269 . 
     In step S 269 , the arithmetic operation circuit  101  designates the value obtained by subtracting the control aperture value AVc from the exposure value EV as the control shutter speed TVc and then the operation proceeds to step S 270 . In step S 270 , the arithmetic operation circuit  101  calculates the control aperture pulse number Pc as the function f of the number of aperture setting steps (AVc−3), before the operation proceeds to step S 271 . In step S 271 , the arithmetic operation circuit  101  sets the flag C to 0, and ends the processing shown in  FIG. 12  before the operation proceeds to step S 5  in  FIG. 4 . 
     In step S 272 , to which the operation proceeds after making a negative decision in step S 263 , the arithmetic operation circuit  101  makes a decision as to whether or not BV&gt;6 is true with regard to the subject luminance BV. The arithmetic operation circuit  101  makes an affirmative decision in step S 272  if Bv&gt;6 is true to proceed to step S 273 , whereas it makes a negative decision in step S 272  if BV&gt;6 is not true and, in this case, the operation proceeds to step S 276 . 
     In step S 273 , the arithmetic operation circuit  101  sets 5 (F 5.6) for the control aperture value AVc and then the operation proceeds to step S 274 . Instep S 274 , the arithmetic operation circuit  101  sets 7 ( 1/125 sec) for the control shutter speed TVc before the operation proceeds to step S 275 . Instep S 275 , the arithmetic operation circuit  101  designates the value obtained by subtracting the subject luminance BV from the apex value 12 as the control imaging sensitivity SVc and then the operation proceeds to step S 270 . 
     In step S 276 , to which the operation proceeds after making a negative decision in step S 272 , the arithmetic operation circuit  101  makes a decision as to whether or not the subject luminance BV is equal to or greater than 2. If BV≧2 is true, the arithmetic operation circuit  101  makes an affirmative decision in step S 276  to proceed to step S 277 . If, on the other hand, BV≧2 is not true, the arithmetic operation circuit makes a negative decision in step S 276  to proceed to step S 281 . 
     In step S 277 , the arithmetic operation circuit  101  sets the control imaging sensitivity SVc to 6 (ISO  200 ) and then the operation proceeds to step S 278 . In step S 278 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as EV=BV+SVc to determine the exposure value EV, before the operation proceeds to step S 279 . Instep S 279 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as AVc=EV/2−1 to determine the control aperture value AVc and then the operation proceeds to step S 280 . In step S 280 , the arithmetic operation circuit  101  designates the value obtained by subtracting the control aperture value AVc from the exposure value EV as the control shutter speed TVc before the operation proceeds to step S 270 . 
     In step S 281 , to which the operation proceeds after making a negative decision in step S 276 , the arithmetic operation circuit  101  makes a decision as to whether or not BV&gt;1 is true with regard to the subject luminance BV. The arithmetic operation circuit  101  makes an affirmative decision in step S 281  if BV&gt;1 is true to proceed to step S 2 S 2 , whereas it makes a negative decision in step S 281  if BV&gt;1 is not true and, in this case, the operation proceeds to step S 285 . 
     In step S 282 , the arithmetic operation circuit  101  sets 3 (F 2.8) for the control aperture value AVc and then the operation proceeds to step S 283 . Instep S 283 , the arithmetic operation circuit  101  sets 5 ( 1/30 sec) for the control shutter speed TVc before the operation proceeds to step S 284 . Instep S 284 , the arithmetic operation circuit  101  designates the value obtained by subtracting the subject luminance BV from the apex value 8 as the control imaging sensitivity SVc and then the operation proceeds to step S 270 . 
     In step S 285 , to which the operation proceeds after making a negative decision in step S 281 , the arithmetic operation circuit  101  makes a decision as to whether or not BV&lt;−9 is true with regard to the subject luminance BV. The arithmetic operation circuit  101  makes an affirmative decision in step S 285  if BV&lt;−9 is true to proceed to step S 286 , whereas it makes a negative decision in step S 285  if BV&lt;−9 is not true and, in this case, the operation proceeds to step S 287 . 
     In step S 286 , the arithmetic operation circuit  101  sets the luminance BV to −9 (control limit) and then the operation proceeds to step S 287 . In step S 287 , the arithmetic operation circuit  101  sets the control imaging sensitivity SV to 7 (ISO  400 ) before the operation proceeds to step S 288 . Instep S 288 , the arithmetic operation circuit  101  sets the control aperture value AVc to 3 (F 2.8) and then the operation proceeds to step S 289 . 
     In step S 289 , the arithmetic operation circuit  101  executes an arithmetic operation expressed as EV=BV+SVc to determine the exposure value EV before the operation proceeds to step S 290 . Instep S 290 , the arithmetic operation circuit  101  designates the value obtained by subtracting 3 (AVc) from the exposure value EV as the control shutter speed TVc and then the operation proceeds to step S 270 . 
     The processing executed in step S 261  through S 290  as described above corresponds to the exposure calculation executed when the “auto mode” is set as the photographing mode and the “imaging sensitivity auto setting” is on. 
     (Display Processing) 
     The display processing executed in step  6  in  FIG. 4  is now described in detail in reference to the flowchart presented in  FIG. 13 . In step S 301  in  FIG. 13 , the arithmetic operation circuit  101  makes a decision as to whether or not the photographing mode flag M is currently set to 0. If M=0 (auto mode), the arithmetic operation circuit  101  makes an affirmative decision in step S 301  to proceed to step S 302 , whereas if M≠0 (i.e., if the A mode is currently selected in this example), it makes a negative decision in step S 301  to proceed to step S 306 . 
     In step S 302 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on the segment  205  to indicate “auto mode”, before the operation proceeds to step S 303 . In step S 303 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto setting mode flag A is currently set to 1. The arithmetic operation circuit  101  makes an affirmative decision in step S 303  if A=1 (if the imaging sensitivity auto setting is on) to proceed to step S 304 , whereas it makes a negative decision in step S 303  if A≠1 (if the imaging sensitivity auto setting is off) and, in this case, the operation proceeds to step S 305 . 
     In step S 304 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “ISO” at the segment  201  and “Auto” at the segment  202 , and then the operation proceeds to step S 305 . 
     In step S 306 , to which the operation proceeds after making a negative decision in step S 301 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on the segment  206  to indicate “A mode” and then the operation proceeds to step S 307 . In step S 307 , the arithmetic operation circuit  101  makes a decision as to whether or not the sensitivity auto control mode flag S is currently set to 1. The arithmetic operation circuit  101  makes an affirmative decision in step S 307  if S=1 (if the sensitivity auto control mode is selected) to proceed to step S 308 , whereas it makes a negative decision in step S 307  if S=0 (if the sensitivity auto control mode has been cleared) to proceed to step S 305 . 
     In step S 308 , the arithmetic operation circuit  101  makes a decision as to whether or not the flag C is currently set to 1. The arithmetic operation circuit  101  makes an affirmative decision in step S 308  if C=1 (if the imaging sensitivity has been altered from the imaging sensitivity setting SVs in the sensitivity auto control mode) to proceed to step S 309 , whereas it makes a negative decision in step S 308  if C=0 (if the imaging sensitivity has remained unchanged from the imaging sensitivity setting SVs) and, in this case, the operation proceeds to step S 310 . 
     In step S 309 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to flash “ISO” at the segment  201  and “Auto” at the segment  202 , before the operation proceeds to step S 305 . In step S 310 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to turn on “ISO” at the segment  201  and “Auto” at the segment  202  and then the operation proceeds to step S 305 . 
     In step S 305 , the arithmetic operation circuit  101  transmits an instruction for the display device  109  to bring up a display indicating the shutter speed, the aperture value and the number of remaining frames and ends the processing shown in  FIG. 13 . The operation subsequently proceeds to step S 7  in  FIG. 4 . 
     (Imaging Sequence Processing) 
     The imaging sequence processing executed in step S 8  in  FIG. 4  is explained in detail in reference to the flowchart presented in  FIG. 14 . In step S 401  in  FIG. 14 , the arithmetic operation circuit  101  outputs an instruction for the shutter control circuit  103  to supply power to magnets (not shown) at the shutter  104  so as to keep both the front curtain and the rear curtain on hold. In step S 402 , the arithmetic operation circuit  101  outputs an instruction for the motor control circuit  105  to start a forward rotation of the sequence motor  106  before the operation proceeds to step S 403 . As a result, a mirror-up operation of the mirror (not shown) and an aperture setting operation for the aperture start. 
     In step S 403 , the arithmetic operation circuit  101  detects an aperture pulse number Pk indicating the number of aperture pulses from the signal input thereto from the aperture position detection device  107  and then the operation proceeds to step S 404 . In step S 404 , the arithmetic operation circuit  101  makes a decision as to whether or not a relationship expressed as Pk≧Pc exists between the detected aperture pulse number Pk and the control aperture pulse number Pc. The arithmetic operation circuit  101  makes an affirmative decision in step S 404  if Pk≧PC is true to proceed to step S 405 , whereas if Pk≧Pc is not true, the arithmetic operation circuit  101  makes a negative decision in step S 404 . After making a negative decision, the operation returns to step S 403  to continue the aperture setting operation. 
     In step S 405 , the arithmetic operation circuit  101  outputs an instruction for the aperture engaging device  108  to engage the aperture and then the operation proceeds to step S 406 . In step S 406 , the arithmetic operation circuit  101  makes a decision as to whether or not the mirror-up operation has been completed. The arithmetic operation circuit  101  makes an affirmative decision in step S 406  if an ON signal has been input from the sequence switch SW 1  to proceed to step S 407 , whereas it makes a negative decision in step S 406  if an ON signal has not been input from the sequence switch SW 1 . After making a negative decision, the decision-making processing is repeatedly executed while the mirror-up operation continues. 
     In step S 407 , the arithmetic operation circuit  101  outputs an instruction for the motor control circuit  105  to stop the sequence motor  106 , and then the operation proceeds to step S 408 . It is to be noted that the sequence drive device (not shown) assumes a structure that allows the aperture engaging device  108  to completely engage the aperture before the mirror-up operation ends. In step S 408 , the arithmetic operation circuit  101  waits in standby over a predetermined length of time (until at least any rebound occurring in the mirror-up operation stops) and then the operation proceeds to step S 409 . 
     In step S 409 , the arithmetic operation circuit  101  engages the timing circuit  124  in generation of a drive signal, thereby starting drive of the image sensor  121 , and then the operation proceeds to step S 410 . In response, the image sensor  121  starts electrical charge storage. 
     In step S 410 , the arithmetic operation circuit  101  outputs an instruction for the shutter control circuit  103  to stop the power supply to the corresponding magnet (not shown) at the shutter  104  so as to release the hold on the front curtain, before the operation proceeds to step S 411 . In response, the shutter front curtain starts running and the image sensor  121  stores electrical charges corresponding to the intensity of the subject light having reached the imaging surface of the image sensor  121 . In step S 411 , the arithmetic operation circuit  101  releases the hold on the rear curtain after a length of time (=2 −TVc ) corresponding to the control shutter speed TVc elapses. More specifically, the arithmetic operation circuit  101  outputs an instruction for the shutter control circuit  103  to stop the power supply to the corresponding magnet (not shown) at the shutter  104 , and then the operation proceeds to step S 412 . In response, the shutter rear curtain starts running, thereby blocking the subject light advancing toward the image sensor  121 . 
     Instep S 412 , the arithmetic operation circuit  101  waits in standby until the shutter rear curtain run is completed, and then the operation proceeds to step S 413 . The length of this wait is set to a length of time required for the rear curtain to complete its run and completely shield the imaging area at the image sensor  121 . In step S 413 , the arithmetic operation circuit  101  ends the electrical charge storage at the image sensor  121  before the operation proceeds to step S 414 . In step S 414 , the arithmetic operation circuit  101  outputs an instruction for the motor control circuit  105  to start a reverse rotation of the sequence motor  106  and then the operation proceeds to step S 415 . In response, a mirror-down operation of the mirror (not shown) and a reset operation for resetting the aperture to the open setting start. In step S 415 , the arithmetic operation circuit  101  outputs an instruction for the timing circuit  124  to prompt a read out of the stored electrical charges from the image sensor  121  and then the operation proceeds to step S 416 . 
     In step S 416 , the arithmetic operation circuit  101  engages the ASIC  123  in image processing before the operation proceeds to step S 417 . In step S 417 , the arithmetic operation circuit  101  engages the ASIC  123  in image compression processing before the operation proceeds to step S 418 . In step S 418 , the arithmetic operation circuit  101  records the image data, having been stored into the buffer memory  125  allowing the image compression, into the recording medium  26 , and then the operation proceeds to step S 419 . 
     In step S 419 , the arithmetic operation circuit  101  makes decision as to whether or not the mirror-down operation has been completed. The arithmetic operation circuit  101  makes an affirmative decision in step S 419  if an ON signal has been input from the sequence switch SW 1  to proceed to step S 420 , whereas it makes a negative decision in step S 419  if an ON signal has not been input from the sequence switch SW 1  and, in this case, the decision-making processing is repeatedly executed while the mirror-down operation continues. 
     In step S 420 , the arithmetic operation circuit  101  outputs an instruction for the motor control circuit  105  to stop the sequence motor  106 , thereby ending the processing shown in  FIG. 14  and the operation subsequently returns to step S 2  in  FIG. 4 . The sequence of photographing processing thus ends. 
     The following operations and advantages can be achieved in the embodiment described above.
     (1) At least either the “auto mode” or the “A mode” may be selected as the photographing mode in the electronic camera, and the “imaging sensitivity auto setting” is allowed to enter an ON state while the electronic camera is set in the “auto mode” whereas operations in the “imaging sensitivity auto setting” ON condition are not executed if the electronic camera is set in the “A mode”. Operations in the “auto mode” in which the electronic camera automatically selects settings related to the exposure (except for the imaging sensitivity) and operations under the “imaging sensitivity auto setting” ON condition in which the electronic camera automatically determines the imaging sensitivity regardless of the current imaging sensitivity setting do not conflict with each other. By allowing these operations, which do not conflict with each other, to be executed in combination, it is ensured that the user is able to ascertain the setting statuses with ease.   (2) At least either the “auto mode” or the “A mode” can be selected as the photographing mode in the electronic camera, and the “sensitivity auto control mode” can be selected while the electronic camera is set in the “A mode”, where as operations in the “sensitivity auto control mode” are not executed if the electronic camera is set in the “auto mode”. Operations in the “A mode”, in which the electronic camera automatically selects the exposure-related settings by using the current aperture value setting, and the sensitivity auto control under which the exposure calculation is executed based upon the current imaging sensitivity setting selected in the electronic camera and the calculated subject luminance and exposure calculation is executed again by automatically adjusting the imaging sensitivity if the optimal exposure is not achieved through the initial exposure calculation do not conflict with each other. By allowing these operations, which do not conflict with each other, to be executed in combination, it is ensured that the user is able to ascertain the setting statuses with ease.   (3) When the electronic camera is set in the “auto mode”, ON/OFF instructions with regard to the “imaging sensitivity auto setting” are issued via a sensitivity setting operation member (i.e., the imaging sensitivity switch SW 4  operated in response to an operation of the imaging sensitivity button). In other words, since operations related to the imaging sensitivity (imaging sensitivity adjustment operation and ON/OFF operation for the “imaging sensitivity auto setting”) can be executed via a common operation member, better operability for the user is assured.   (4) when the electronic camera is set in the “A mode”, instructions for setting/clearing the “sensitivity auto control mode” are issued via an operation member (i.e., the sensitivity auto control mode switch SW 5  operated in response to an operation of the sensitivity auto control mode button) different from the sensitivity setting operation member. As a result, the operations for setting/clearing the sensitivity auto control mode never become mixed up with the operations in (3) above, thereby assuring better ease of operation for the user.   (5) If an instruction to switch from the “auto mode” to the “A mode” is issued while the “image sensitivity auto setting” is on, the setting having been stored at the time of the previous “A mode” operation is set as the imaging sensitivity after the change over to the “A mode”. In addition, if an instruction to switch from the “auto mode” to the “A mode” is issued while the “imaging sensitivity auto setting” is off, the setting effective in the current “auto mode” is carried over as the imaging sensitivity after the change over to the “A mode”. This structure allows the user to operate the camera without becoming disconcerted by a change in the imaging sensitivity when the photographing mode is altered.   (6) If no data indicating the imaging sensitivity are stored in the situation described in (5) above, that is, when information indicating the imaging sensitivity set in the previous “A mode” or information indicating the setting of the most recent “auto mode” is not stored, the default value, that is, a predetermined initial value (e.g., SVs=5) is selected as the imaging sensitivity after the change over to the “A mode”. As a result, even in the event of data loss, an imaging sensitivity setting error is prevented. This may be a case where stored data has been deleted for some reasons or the “A mode” has never been selected.   (7) In response to an instruction to switch from the “A mode” to the “auto mode”, the setting effective in the current “A mode” is selected as the imaging sensitivity after the change over to the “auto mode”. In addition, if the “imaging sensitivity auto setting” was on while the electronic camera was set in the A mode previously, information indicating the “imaging sensitivity auto setting” ON condition is stored and the “imaging sensitivity auto setting” is turned on a gain based upon the information after the change over to the “auto mode”. This structure allows the user to operate the camera without becoming disconcerted by a change in the imaging sensitivity when the photographing mode is adjusted.   (8) If an imaging sensitivity adjustment operation is executed in the “imaging sensitivity auto setting” ON condition when the electronic camera is set in the “auto mode”, the imaging sensitivity is adjusted starting from the lower limit (ISO  100 ) of the imaging sensitivity adjustment range in response to an upward operation, the imaging sensitivity is adjusted starting at the upper limit (HI-2) of the imaging sensitivity adjustment range in response to a downward operation, and the “imaging sensitivity auto setting” is turned off in either case, thereby assuring better ease of use for the user.   (9) When the electronic camera is set in the “auto mode” and the “imaging sensitivity auto setting” is in an OFF state, the imaging sensitivity auto setting” is turned on in response to a downward operation starting at the lower limit (ISO  100 ) of the imaging sensitivity adjustment range or in response to an upward operation starting at the upper limit (HI-2) of the imaging sensitivity adjustment range and thus, better ease of use for the user is assured.   (10) When automatically adjusting the imaging sensitivity following a failure to achieve the optimal exposure in the electronic camera set in the “A mode” and the “sensitivity auto control mode”, the imaging sensitivity is adjusted (step S 218 ) after setting (step S 217 ) the control shutter speed to a specific value ( 1/30 sec) representing a higher speed than the low-speed side control limit (30 sec). As a result, operations in the “sensitivity auto control mode” can be executed at the shutter speed (which is set to 1/30 sec in the embodiment) at which blurring attributable to shaky hand movement does not occur.   

     (Variation 1) 
     The settings processing may be executed as shown in the flowchart presented in  FIG. 18  instead of the flowchart in  FIG. 5  and also as shown in the flowchart presented in  FIG. 19  instead of the flowchart in  FIG. 7 . The processing in  FIG. 18  differs from that shown in FIG.  5 in that step S 501  is executed in place of step S 109  and step S 502  is executed in place of step S 112 . 
     In settings processing  1  shown in  FIG. 18 , the imaging sensitivity setting can be selected when the “auto mode” is set for the photographing mode over a range “ISO 100” through “ISO 1600”, which does not include the sensitivity levels “HI-1” and “HI-2” higher than “ISO 1600”.  FIG. 20  shows how the imaging sensitivity may be switched in response to imaging sensitivity adjustment instructions in the “auto mode” in variation 1. The electronic camera sequentially switches the imaging sensitivity in the order of, for instance, “Auto”-“ISO 100”-“ISO 200”-“ISO 400”-“ISO 800”-“ISO 1600”-“Auto” . . . as shown in  FIG. 20 . 
     The processing in  FIG. 19  differs from the processing in  FIG. 7  in that it includes additional steps S 510  and S 511  executed between step S 145  and step S 146 . When the photographing mode is switched from the “A mode” to the “auto mode”, the imaging sensitivity setting SVs is switched to 9 (ISO  1600 ) (step S 511 ) if the imaging sensitivity setting SVs selected in the “A mode” is greater than  9  (“HI-1” or “HI-2” in this example) (when an affirmative decision is made in step S 510 ) in the processing shown in  FIG. 19 . 
     (Variation 2) 
     While the “A mode” is explained as an example of a photographing mode different from the “auto mode”, a “P mode” or an “S mode” may be selected instead of the “A mode”. In the “P mode”, the electronic camera automatically selects the exposure-related settings in correspondence to the luminance (program auto exposure mode), whereas in the “S mode”, the electronic camera automatically selects the exposure-related settings based upon the current shutter speed setting (shutter speed priority auto exposure mode). 
     (Variation 3) 
     The settings processing may be executed as shown in the flowchart presented in  FIG. 21  instead of the flowchart in  FIG. 5  and also as shown in the flowchart presented in  FIG. 22  instead of the flowchart in  FIG. 6 . The processing shown in  FIG. 21  differs from the processing shown in  FIG. 5  in that it includes additional steps S 1001  through S 1004  executed after step S 107 . The processing in  FIG. 22  differs from the processing shown in  FIG. 6  in that step S 127  is not executed in the processing in  FIG. 22 . The imaging sensitivity having been stored at the time of the previous “A mode” operation is set for the imaging sensitivity after the change over to the “A mode” in response to an instruction to switch from the “auto mode” to the “A mode” issued in the “imaging sensitivity auto setting” ON condition in the embodiment described above. In variation  3 , however, either the imaging sensitivity having been set in the “auto mod” under the “imaging sensitivity auto setting” OFF condition or the imaging sensitivity having been stored at the time of the previous “A mode” operation, whichever setting that was selected more recently, is set as the imaging sensitivity after the change over to the “A mode” in response to an instruction to switch from the “auto mode” to the “A mode” issued under the “imaging sensitivity auto setting” ON condition. By setting the value manually selected by the user most recently as the imaging sensitivity, the sense of disruption that may be experienced by the user as the imaging sensitivity is altered in response to a switch in the photographing mode can be further reduced. 
     The above described embodiments are examples and various modifications can be made without departing from the scope of the invention.