Patent Publication Number: US-2010128146-A1

Title: Imaging apparatus, image storage apparatus, imaging method, storage method, recording medium recording imaging program, and recording medium recording storage program

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Divisional Application of U.S. application Ser. No. 12/392,965 filed Feb. 25, 2009 which is a Divisional of U.S. application Ser. No. 11/345,944 filed Feb. 2, 2006 (now U.S. Pat. No. 7,634,186), which is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-027883, filed Feb. 3, 2005, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an imaging apparatus particularly suitable for, for example, a digital still camera having an autofocus function, an image storage apparatus, an imaging method, a storage method, a recording medium recording an imaging program, and a recording medium recording a storage program. 
     2. Description of the Related Art 
     Heretofore, a technique has been devised wherein, in order to capture images focused on a subject desired by a photographer even when the distance from the subject rapidly changes or there are many different objects around the subject, a plurality of images of different focal distances is captured in one imaging operation (e.g., Patent document 1). 
     [Patent document 1] Jpn. Pat. Appln. KOKAI Publication No. 11-177873 
     However, in the technique of the above-mentioned patent document, a high-speed variable-focus lens capable of instantaneously changing a focal distance and a drive circuit thereof are provided in order to sequentially capture a plurality of images of focal distances other than the focal distance originally regarded as proper, thus resulting in a complicated and expensive configuration of the apparatus and requiring a memory with higher capacity to store a plurality of images obtained by photographing. 
     In other words, the technique of the above-mentioned patent document takes a blunderbuss approach, which results in much load on the apparatus and is therefore not suitable for small and light digital cameras of a type that places great importance on, for example, compactness and battery life. 
     BRIEF SUMMARY OF THE INVENTION 
     One of preferred aspects of this invention is an imaging apparatus comprising: a photographing unit which has an autofocus function and captures a subject image; an instruction unit which instructs to perform photography by the photographing unit; and a photographing control unit which causes the photographing unit to capture a still image by actuating the autofocus function and a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained, in accordance with the instruction from the instruction unit. 
     Furthermore, one of the preferred aspects of this invention is an imaging apparatus comprising: a photographing unit which has an autofocus function and captures a subject image; an instruction unit which instructs to perform photography by the photographing unit; a scene program setting section in which a plurality of conditions for the photography by the photographing unit has been preprogrammed/preset; a scene selection unit which selects one of the plurality of photographing conditions set in the scene program setting section; and a photographing control unit which, in accordance with the instruction from the instruction unit, causes the photographing unit to capture a still image based on the program/setting of the photographing condition selected in the scene selection unit, and to capture a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained when the selected photographing condition is a predetermined condition. 
     Furthermore, one of the preferred aspects of this invention is an image storage apparatus comprising: a storage unit which differentiates sequentially captured still images including a still image obtained by autofocus photography and a still image obtained in photography performed by moving a lens to a predesignated position where a fixed depth of field can be obtained and which assigns an order of priority to the still images before storing them in relation to each other; a selection unit which selects one from a plurality of sets of still images stored in the storage unit in relation to each other; a display control section which causes a still image with a higher order of priority selected by the selection unit to be displayed among the still images stored in relation to each other; a replacement instruction section which instructs to replace the still image displayed by the display control section; and a rewrite section which rewrites an order of priority of the still images stored in the storage unit in accordance with the instruction of the replacement instruction section. 
     Furthermore, one of the preferred aspects of this invention is a imaging method for an imaging apparatus comprising a photographing unit which has an autofocus function and captures a subject image, and the method comprises: an instruction step of instructing to perform photography by the photographing unit; and a photographing control step of causing the photographing unit to capture a still image by actuating the autofocus function and a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained, in accordance with the instruction in the instruction step. 
     Furthermore, one of the preferred aspects of this invention is a imaging method for an imaging apparatus comprising a photographing unit which has an autofocus function and captures a subject image, and the method comprises: an instruction step of instructing to perform photography by the photographing unit; a scene program setting step in which a plurality of conditions for the photography by the photographing unit has been preprogrammed/preset; a scene selection step of selecting one of the plurality of photographing conditions set in the scene program setting step; a photographing control step of causing the photographing unit to capture a still image based on the program/setting of the photographing condition selected in the scene selection step and to capture a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained when the selected photographing condition is a predetermined condition accordance with the instruction in the instruction step. 
     Furthermore, one of the preferred aspects of this invention is a storage method for an image storage apparatus comprising a storage unit which stores still images, and the method comprises: a storage control step of differentiating sequentially captured still images including a still image obtained by autofocus photography and a still image obtained in photography performed by moving a lens to a predesignated position where a fixed depth of field can be obtained, and assigning an order of priority to the still images before storing them in the storage unit in relation to each other; a selection step of selecting one from a plurality of sets of still images stored in the storage unit in relation to each other; a display control step of displaying a still image with a higher order of priority selected in the selection step among the still images stored in relation to each other; a replacement instruction step of instructing to replace the still image displayed in the display control step; and a rewrite step of rewriting the order of priority of the still images stored in the storage unit in accordance with the instruction in the replacement instruction step. 
     Furthermore, one of the preferred aspects of this invention is a recording medium recording an imaging program executed by a computer built into an imaging apparatus comprising a photographing unit which has an autofocus function and captures a subject image, and the computer executes: an instruction step of instructing to perform photography by the photographing unit; and a photographing control step of causing the photographing unit to capture a still image by actuating the autofocus function and a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained, in accordance with the instruction in the instruction step. 
     Furthermore, one of the preferred aspects of this invention is a recording medium recording an imaging program executed by a computer built into an imaging apparatus comprising a photographing unit which has an autofocus function and captures a subject image, and the computer executes: an instruction step of instructing to perform photography by the photographing unit; a scene program setting step in which a plurality of conditions for the photography by the photographing unit has been preprogrammed/preset; a scene selection step of selecting one of the plurality of photographing conditions set in the scene program setting step; a photographing control step of, in accordance with the instruction in the instruction step, causing the photographing unit to capture a still image based on the program/setting of the photographing condition selected in the scene selection step, and to capture a still image by moving a lens to a predesignated position where a fixed depth of field can be obtained when the selected photographing condition is a predetermined condition. 
     Furthermore, one of the preferred aspects of this invention is a recording medium recording a storage program executed by a computer built into an image storage apparatus comprising a storage unit which stores still images, and the computer executes: a storage control step of differentiating sequentially captured still images including a still image obtained by autofocus photography and a still image obtained in photography performed by moving a lens to a predesignated position where a fixed depth of field can be obtained, and assigning an order of priority to the still images before storing them in the storage unit in relation to each other; a selection step of selecting one from a plurality of sets of still images stored in the storage unit in relation to each other; a display control step of displaying a still image with a higher order of priority selected in the selection step among the still images stored in relation to each other; a replacement instruction step of instructing to replace the still image displayed in the display control step; and a rewrite step of rewriting the order of priority of the still images stored in the storage unit in accordance with the instruction in the replacement instruction step. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1A  and  FIG. 1B  are perspective views showing an external configuration of a digital camera according to a first embodiment of the present invention; 
         FIG. 2  is a block diagram showing a functional configuration of an electronic circuit according to the first embodiment; 
         FIG. 3  is a flowchart showing processing contents in a photographing mode according to the first embodiment; 
         FIG. 4A  and  FIG. 4B  are diagrams illustrating two photographing results according to the first embodiment: a photographic image by a fixed focus and a photographic image by autofocus; 
         FIG. 5  is a flowchart showing processing contents in a photographing mode according to a second embodiment of the present invention; 
         FIG. 6  is a flowchart showing processing contents in a photographing mode according to a third embodiment of the present invention; 
         FIG. 7  is a flowchart showing processing contents in a photographing mode according to a fourth embodiment of the present invention; 
         FIG. 8  is a flowchart showing processing contents in a photographing mode according to a fifth embodiment of the present invention; 
         FIG. 9  is a flowchart showing processing contents in a photographing mode according to a sixth embodiment of the present invention; 
         FIG. 10  is a flowchart showing processing contents in a photographing mode according to a seventh embodiment of the present invention; 
         FIG. 11  is a flowchart showing processing contents in a photographing mode according to an eighth embodiment of the present invention; 
         FIG. 12  is a flowchart showing processing contents in a photographing mode according to a ninth embodiment of the present invention; 
         FIG. 13  is a flowchart showing processing contents in a photographing mode according to a tenth embodiment of the present invention; and 
         FIG. 14  is a flowchart showing processing contents in a photographing mode according to an eleventh embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     A first embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
       FIG. 1A  and  FIG. 1B  show an external configuration of the digital camera, and  FIG. 1A  is a perspective view mainly showing a foreside thereof, while  FIG. 1B  is a perspective view mainly showing a rear side thereof. 
     In a digital camera  1 , there are arranged, on a front surface of a substantially rectangular thin-plate-shaped body  2 , a photographing lens  3 , a self-timer lamp  4 , an optical finder window  5 , a flash light emitting unit  6  (auxiliary illumination unit) and a microphone  7 . There are arranged, on a right edge side of an upper surface (for a user), a power supply key  8  and a shutter key  9  (an instruction unit, a detection unit). 
     The photographing lens  3  has a lens configuration having a variable focus function which is a zoom function ranging from a wide-angle area to a telescopic area, and an autofocus (AF) function. 
     The power supply key  8  is a key operated every time a power supply is turned on/off, and the shutter key  9  instructs to perform photography in a photographing mode. 
     Furthermore, on a rear surface of the digital camera  1 , there are arranged a tele(T)-key  10 , a wide (W)-key  11 , a photographing (R) mode key  12 , a reproduction (P) mode key  13 , a ring key  14 , a set key  15 , a menu key  16 , an optical finder  17 , a speaker section  18 , a macro key  19 , a flash key  20  and a display section  21 . 
     The tele-key  10  and the wide-key  11  are operated to vary a focal distance of the photographing lens  3  to a wide-angle side or a telescopic side. 
     The photographing mode key  12  is operated in a state where the power supply is turned off to automatically turn on the power supply, thereby shifting to a photographing mode to capture a still image. On the other hand, the photographing mode key  12  is repeatedly operated in a state where the power supply is turned on to circularly select and set a state of capturing still images, a state of capturing moving images or a state of recording sound. 
     The reproduction mode key  13  is operated in the state where the power supply is turned off to automatically turn on the power supply, thereby shifting to a reproduction mode. 
     The ring key  14  integrally forms vertical and horizontal item selection keys, and an item selected at the moment is set by the set key  15  located in the center of the ring key  14 . 
     The menu key  16  is operated to select various menu items and the like. 
     The macro key  19  is operated to switch between ordinary photography and macro photography in the photographing mode of the still image. 
     The flash key  20  is operated to switch the light emission mode of the flash light emitting unit  6 . 
     The display section  21  comprises a color liquid crystal panel with a backlight, and it performs monitor display of through images as an optical finder in the photographing mode, while reproducing/displaying a selected image or the like in a reproduction mode. 
     It is to be noted that although not shown in the drawings, there are provided, on a bottom surface of the digital camera  1 , a memory card slot for insertion/removal of a memory card used as a recording medium, a serial interface connector such as a universal serial bus (USB) connector for connection to an external personal computer or the like. 
     Next, a configuration of an electronic circuit of the digital camera  1  will be described with  FIG. 2 . 
     In a monitoring state in the photographing mode, a motor (M)  31  is driven to properly move the position of some lenses, more specifically, a zoom lens and a focus lens, in a lens optical system  32  constituting the photographing lens  3 . A CCD  33  which is a solid-state image sensing device is disposed at a image focus location in the rear of a photographing optical axis of the lens optical system  32  via an unshown mechanical shutter. The motor (M)  31 , the lens optical system  32  and the CCD  33  correspond to a photographing unit. 
     The CCD  33  is driven for scanning by a timing generator (TG)  34  and a CCD driver  35 , and outputs a photoelectric conversion output corresponding to a formed optical image for one screen at each regular period. 
     This photoelectric conversion output is properly subjected to a gain adjustment for each primary color component of RGB in a state of an analog-value signal, and then sampled and held by a sample and hold (S/H) circuit  36 . 
     The photoelectric conversion output is then converted into digital data in an Analog to Digital (A/D) converter  37 , and subjected to color processing including image interpolation processing and correction processing in a color process circuit  38 . 
     Thus, a luminance signal Y and color-difference signals Cb, Cr in digital values are generated, and they are output to a direct memory access (DMA) controller  39 . 
     The DMA controller  39  temporarily writes the luminance signal Y and the color-difference signals Cb, Cr output by the color process circuit  38  into a buffer in the DMA controller  39  by use of a composite synchronous signal, a memory write enable signal and a clock signal also coming from the color process circuit  38 , and performs a DMA transfer to a DRAM  41  which is used as a buffer memory via a DRAM interface (I/F)  40 . 
     A control unit  42  comprises a CPU  420 , a ROM  421  fixedly storing an operation program used for photography by autofocus and fixed focus described later, a RAM  422  used as a work memory, a photographing control section  423  which controls photography, a judgment section  424  which judges a state in which an in-focus position is difficult to obtain, a focus position setting  425  section which arbitrarily fixes and sets the in-focus position, a bracketing setting section  426  which variably sets predetermined photographing conditions in stages, a scene program setting section  427  into which a plurality of photographing conditions has been preprogrammed, a display control section  428  which controls image display, and a rewrite section  429  which rewrites an order of priority of still images. The control unit  42  controls/operates the entire digital camera  1 . After finishing the DMA transfer of the luminance and color-difference signals to the DRAM  41 , the control unit  42  reads the luminance and color-difference signals from the DRAM  41  via the DRAM interface  40 , and writes them into a VRAM  44  via a VRAM controller  43 . 
     A digital video encoder  45  regularly reads the luminance and color-difference signals from the VRAM  44  via the VRAM controller  43 , and generates a video signal on the basis of these data and thus outputs it to the display section  21 . 
     The display section  21  functions as a monitor display section (electronic view finder) in the image photographing mode as described above, and performs display based on the video signal from the digital video encoder  45  to display in real time an image based on image information imported from the digital video encoder  45  at the moment. 
     Thus, a trigger signal is generated if the shutter key  9  is operated with such timing that a still image is desired to be captured while the image at the moment which is a so-called through image is being displayed as a monitor image on the display section  21  in real time. 
     In accordance with the trigger signal, the control unit  42  cancels the DMA transfer to the DRAM  41  of the luminance and color-difference signals for one screen imported from the CCD  33  at the moment. The control unit  42  again drives the unshown mechanical shutter and the CCD  33  at a shutter speed corresponding to a proper exposure condition to obtain activation and color-difference signals for one screen, and transfers then to the DRAM  41 . The control unit  42  then stops this path, and shifts to a state of storage/save. 
     In this state of storage/save, the control unit  42  reads the luminance and color-difference signals for one frame written in the DRAM  41  via the DRAM interface  40  in a unit called a basic block of vertical 8 pixels×horizontal 8 pixels for each of the components of Y, Cb and Cr, and writes them into a Joint Photograph coding Experts Group (JPEG) circuit  46 . In this JPEG circuit  46 , data compression is carried out by processing such as adaptive discrete cosine transform (ADCT) and Huffman coding which is an entropy coding method. 
     Furthermore, obtained code data is read from the JPEG circuit  46  as a data file for one image, and written into an internal memory  47  (storage unit) which is a storage medium of the digital camera  1  or into a memory card  48  (storage unit) detachably attached to the digital camera  1 . 
     Then, the control unit  42  again actuates the path from the CCD  33  to the DRAM  41  along with completion of compression processing of the luminance and color-difference signals for one frame or completion of writing of totally compressed data into the internal memory  47  or the memory card  48 . 
     Here, out of the internal memory  47  and the memory card  48 , the memory card  48  is given priority to write and read various kinds of data including data on the still images. That is, data is written into/read from the internal memory  47  in a state where the memory card  48  is removed and not present, whereas data is written into/read from the memory card  48  in a state where the memory card  48  is attached. 
     Moreover, to the control unit  42 , there are connected a key input section  49 , a sound processing section  50 , an acceleration sensor  51  (hand movement detection section) and a flash drive section  52 . 
     The key input section  49  (a photography specifying section, a scene selection section, a selection section, a replacement instruction section) comprises the power supply key  8 , the shutter key  9 , the tele-key  10 , the wide-key  11 , the photographing mode key  12 , the reproduction mode key  13 , the ring key  14 , the set key  15 , the menu key  16 , the macro key  19  and the flash key  20 . Signals associated with the operation of these keys are directly delivered to the control unit  42 . 
     The sound processing section  50  comprises a sound source circuit such as a PCM sound source. During sound recording, the sound processing section  50  digitizes a sound signal input from the microphone section (MIC)  7 , and performs data compression in accordance with a predetermined data file format such as an MPEG-1 audio layer  3  (MP3) standard to create a sound data file, and thus sends it to the internal memory  47  or the memory card  48 . On the other hand, during sound reproduction, the sound processing section  50  decompresses the sound data file sent from the internal memory  47  or the memory card  48  and converts it into an analog form, and drives the speaker section (SP)  18  provided on the rear side of the digital camera  1  to output sound loud. 
     The acceleration sensor  51  detects a movement acceleration in a direction along a plane parallel with an imaging surface of the CCD  33 , and digitizes its detection output and sends it to the control unit  42 . 
     The flash drive section  52  charges a high-capacity condenser for an unshown flash when capturing a still image, and then drives the flash light emitting unit  6  for flashing under the control of the control unit  42 . 
     Thus, when it is selected to capture moving images instead of the still image, a series of operations is sequentially executed at a proper frame rate, for example, 30 [frames/second] at the start, wherein the above-mentioned still image data is obtained and compressed in the JPEG circuit  46  at the first operation of the shutter key  9 , and then stored in the internal memory  47  or the memory card  48 . At the point where the shutter key  9  is operated second time or where a predetermined time limit, for example, 30 seconds have passed, the series of still image data files is collectively reset as data files (AVI files) of motion JPEG. 
     Furthermore, during the reproduction mode, the control unit  42  selectively reads the image data stored in the internal memory  47  or the memory card  48 . The JPEG circuit  46  decompresses the compressed image data in a procedure totally reverse to that in compressing the data in the photographing mode. After the decompressed image data is retained in the DRAM  41  via the DRAM interface  40 , contents retained in the DRAM  41  are stored in the VRAM controller  43  via the DRAM interface  40 , and the image data is regularly read from the VRAM  44  to generate a video signal, which is reproduced/output on the display section  21 . 
     When the selected image data is a moving image instead of a still image, individual still image data constituting a selected moving image file is reproduced sequentially in time. At the point where the reproduction of the final still image data is terminated, reproduction/display is performed only using the still image data located at the head until a next reproduction instruction is issued. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in this digital camera  1 , the shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus (the lens is moved to a predesignated position) described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in the ROM within the control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
       FIG. 3  shows contents of processing performed when a still image is captured in the photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and the CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on the display section  21  (step A 01 ), and also judging whether or not the shutter key  9  of the key input section  49  has been half-pressed (step A 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step A 02 . The focus lens of the lens optical system  32  is moved in accordance with the focal distance and the AE value corresponding to the position of the zoom lens of the lens optical system  32  at the moment, so that photography is performed with a fixed focus allowing a fixed great depth of field to be obtained, and an obtained image is retained in the DRAM (step A 03 ). 
     In conjunction with this, the value of a distance to a subject is accurately measured, and the focal distance value is locked. On the other hand, a electronic sound such as beeping is output loud by the speaker section  18  to inform a user that the still image has been captured with the fixed focus (step A 04 ). 
     Next, a proper exposure value is obtained from a state in which the autofocus position is locked. After setting an aperture value and a shutter speed from the exposure value and locking them (step A 05 ), it is repeatedly judged whether or not the shutter key  9  has been further fully pressed (step A 06 ) and whether or not it is still half-pressed (step A 07 ), thus waiting for the shutter key  9  to be fully pressed while the AF and AE states are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-pressed state of the shutter key  9  is cancelled, this is judged in step A 07 , concluding that the actual photography has not been reached. Data on the still image retained in the DRAM  41  at the moment and obtained by the photography based on the fixed focus in step A 03  is deleted for nullification (step A 08 ), and a return is made again to the processing in step A 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step A 06 , and a still image is captured while the photographing conditions in accordance with the autofocus function is being locked, thereby obtaining image data (step A 09 ). 
     Subsequently, both data on the still image obtained with the autofocus and data on the still image obtained by the fixed focus in step A 03  are compressed and converted into files in the JPEG circuit  46 , and stored/saved on the internal memory  47  or the memory card  48  (step A 10 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step A 01  to again prepare for next photography. 
     In this case, for data files to be recorded on the internal memory  47  or the memory card  48 , a file name such as “200309080001a.jpg” is set and stored for the data file of the still image captured with the autofocus, while a file name such as “200309080001b.jpg” is set and stored for the data file of the still image captured by the fixed focus. These two data files can thus be recognized as a pair and differentiated. 
     In the above-mentioned file names, “200309080001” indicates that the photography was performed on “2003 (year)09(month)08(day)” “0001(first)”. Photographing condition data additionally set in the file include not only typical information such as photographing date and time, the ISO film speed, an image size, a shutter speed, an aperture (F) value and a while balance, but also identification information indicating whether the photography was conducted by the actuation of the autofocus function or by the fixed focus. 
     Therefore, it is possible not only to identify, owing to the file names of the stored data files, that the two still images are paired and were sequentially captured but also to know from the photographing condition data whether the photography was conducted by the actuation of the autofocus function or by the fixed focus. 
       FIG. 4A  illustrates a state where the still image captured with the fixed focus is read and displayed on the display section  21  in the reproduction mode, wherein characters “PF” indicating that the photography was conducted by the fixed focus are displayed, for example, at an upper left end in a screen on the basis of the photographing condition data. 
     On the other hand,  FIG. 4B  illustrates a state where the still image captured by the actuation of the autofocus function and stored to be paired with the still image shown in  FIG. 4A  is read and displayed on the display section  21 , wherein characters “AF” indicating that the photography was conducted by the actuation of the autofocus function are displayed, for example, at the upper left end in the screen on the basis of the photographing condition data. 
     Thus, as understood referring to  FIG. 4A  and  FIG. 4B , even when the still image captured by the actuation of the autofocus function is out of focus or blurred due to a factor such as the hand movement, it is highly likely that the still image captured with the fixed focus immediately before the autofocus photography is sufficiently vivid. This makes it possible to capture and store a still image focused on the desired subject with a high probability without particularly increasing in size and complicating the apparatus and circuits. 
     In addition, the still image based on the fixed focus is generally captured in the so-called half-press operation of the shutter key  9  to lock the autofocus (AF) or automatic exposure (AE) in many cameras, and the still image based on the autofocus is captured in the subsequent full-press operation, thereby allowing the user to obtain the still image based on the fixed focus without feeling discomfort. 
     Furthermore, when the actual photography by the autofocus function has not been reached, the data on the image based on the fixed focus captured earlier is destroyed, and it is therefore ensured that the unnecessary waste of limited storage capacity in the internal memory  47  or the memory card  48  can be avoided. 
     It is to be noted that the half-press operation of the shutter key  9  causes the photography based on the fixed focus allowing a fixed great depth of field to be obtained, but the photography based on the fixed focus may be performed after AF photography in step A 09 . 
     Second Embodiment 
     A second embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Furthermore, a lens optical system  32  constituting a photographing lens  3  is adapted to an autofocus function in a contrast method, so that a position where a contrast value is the highest is judged by a control unit  42  from a change in contrast of an image formed in a CCD  33  by movement of a focus lens. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein the focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
       FIG. 5  shows contents of processing performed when a still image is captured in a photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and the CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step B 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step B 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step B 02 . Thus, a clocking operation is started by an internal timer in the control unit  42  (step B 03 ), and an AF operation is also started to measure the value of a distance to a subject (step B 04 ). 
     Subsequently, it is repeatedly judged whether or not this AF operation is completed to obtain the value of the distance to the subject (step B 05 ), or whether or not the internal timer in the control unit  42  registers a constant clocking value, for example, “three (seconds)” (step B 06 ), thus waiting for the AF processing to terminate or the internal timer in the control unit  42  to register a constant clocking value. 
     Thus, when the AF processing has terminated before the internal timer in the control unit  42  has registered a constant clocking value, this is judged in step B 05 . Then, a proper exposure value is obtained by the AE processing from a state in which an autofocus position obtained by the AF processing is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step B 07 ). 
     On the other hand, when the clocking value of the internal timer in the control unit  42  has become constant before completion of the AF processing, it is judged in step B 06  that the AF processing in the contrast method is difficult, for example, under a low illumination environment. Thus, a fixed focus is set from a focal distance of the lens optical system  32  set at the moment, and a proper exposure value is obtained by the AE processing, and then an aperture value and a shutter speed are set from the exposure value and locked (step B 08 ). 
     After the processing in step B 07  or B 08 , it is repeatedly judged this time whether or not the shutter key  9  has been further fully pressed (step B 09 ) or whether or not it is still half-pressed (step B 10 ), thus waiting for the shutter key  9  to be fully pressed while states of an in-focus position and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step B 10 . Thus, the locking of the in-focus position and AE states is cancelled, and a return is made again to the processing in step B 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the in-focus position and AE states are locked, this is judged in step B 09 , and a still image is captured while the in-focus position and AE value corresponding to a focusing method set at the moment are locked, thereby obtaining image data (step B 11 ). The obtained data on the still image is compressed and converted into a file in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step B 12 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step A 01  to again prepare for next photography. 
     Thus, for example, when accurate contrast detection can not be achieved due to insufficient illumination of the subject in a camera having the autofocus function adopting the contrast method, a switch is automatically made from the autofocus function to the fixed focus as necessary to capture the still image, thereby making it possible to reduce the possibility of missing the right moment to press the shutter and ensuring that the photography is performed. 
     In this embodiment, a judgment is made particularly from whether or not time required for the autofocus has reached a certain value, so that a judgment result can be obtained in a short time, and a proper response can be made. 
     It is to be noted that a state in which an accurate focal distance in the AF processing can not be obtained is judged by the time from the start to the termination of the AF processing in the embodiment described above. However, the present invention is not limited thereto. For example, the AE processing may be first performed, and a judgment may be made from the exposure value or the like obtained by the AE processing. 
     Third Embodiment 
     A third embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
     Furthermore, when photography is performed with this digital camera  1  using flash emission, that is, when an automatic emission mode of a flash is set and a sufficient illumination for a subject can&#39;t be obtained without the flash emission, or when a compulsory emission mode of the flash is set, pre-emission is conducted wherein the flash is pre-flashed before actual light emission of the flash in actual photography, and an amount of light emission in the actual light emission of the flash is corrected in accordance with an amount of light reflected from the subject. 
       FIG. 6  shows contents of processing performed when a still image is captured in a photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step C 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step C 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step C 02 , and the value of a distance to the subject is again accurately measured by the AF processing, and the focal distance value is locked (step C 03 ). A proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step C 04 ). 
     Subsequently, it is judged whether or not to irradiate auxiliary light by the flash emission during photography in accordance with a flash mode set at this point (step C 05 ). 
     This judgment is made, if the set flash mode is the automatic emission mode, depending on whether or not the exposure value locked in the AE processing is at such a level that requires the flash emission, or depending on whether or not the flash mode is set to the compulsory emission mode, or depending on whether the flash mode is not set to an emission prohibited mode. As a result, it is judged whether or not to perform photography with the irradiation of the auxiliary light by the flash emission. When it is determined to perform the photography without the flash emission, an ordinary photographing operation will then be performed which is not associated with the present embodiment, so that this operation is not described below. 
     Furthermore, when the flash mode is the automatic emission mode and the exposure value is at such a level that requires the flash emission, or when the flash mode is set to the compulsory emission mode and the flash emission is therefore performed, this is judged in step C 05 . Next, it is repeatedly judged whether or not the shutter key  9  is fully pressed (step C 06 ) or whether or not it is still half-pressed (step C 07 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step C 07 , and a return is made again to the processing in step C 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step  006 . Thus, the locked state of the AF processing is once cancelled, and the focus lens of a lens optical system  32  is moved to a position which achieves a fixed focus corresponding to a focal distance at that point. In addition, a flash emitting unit  6  is caused to perform pre-emission by a flash drive section  52  in a light emission amount corresponding to the locking of the AE processing, and synchronously with this, a still image is captured with the fixed focus to obtain image data (step C 08 ). At this point, an amount of reflected light for the amount of light emitted by the flash emitting unit  6  is calculated from the obtained image data. 
     Next, the exposure value locked in the AE processing is corrected in accordance with the calculated amount of reflected light, and the focus lens in the lens optical system  32  is returned to the lock position in the AF processing obtained in step C 03 , thus performing the actual photography to capture a still image based on the AF processing while causing the flash emitting unit  6  to perform the actual light emission by the flash drive section  52  (step C 09 ). 
     Then, both obtained data on the still image in the actual photography in accordance with the AF processing and data on the still image in the pre-emission obtained by the fixed focus in step C 08  immediately before the AF processing are compressed and converted into files in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step C 10 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step C 01  to again prepare for next photography. 
     Thus, when flash photography is performed using the flash emitting unit  6 , the pre-emission in the flash photography is effectively utilized to obtain a still image based on the fixed focus, and this still image is stored/saved to be paired with the still image based on the autofocus captured during the actual photography after the pre-emission. Therefore, unnecessary consumption of electric power from a power source battery whose capacity is limited is avoided without wasting emission/driving of the flash emitting unit  6 . In the meantime, even when the still image captured by actuation of an autofocus function is out of focus or blurred due to a factor such as hand movement, it is highly likely that the still image captured with the fixed focus using the pre-emission immediately before the autofocus photography is sufficiently vivid. This makes it possible to avoid a situation where a blurred image can only be obtained at a rare moment to press the shutter and ensuring that the still image focused on the desired subject is captured and stored. 
     Fourth Embodiment 
     A fourth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
       FIG. 7  shows contents of processing performed when a still image is captured in a photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step D 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step D 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step D 02 . First, clocking by an internal timer in the control unit  42  is started (step D 03 ), and the value of a distance to a subject is accurately measured, and the focal distance value is locked (step D 04 ). 
     In addition, a proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step D 05 ). Then, it is repeatedly judged whether or not the shutter key  9  has been further fully pressed (step D 06 ) or whether or not it is still half-pressed (step D 07 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step D 07 , and a return is made again to the processing in step D 01  concluding that the actual photography has not been reached. 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step D 06 . Thus, depending on whether or not a clocking value of the internal timer in the control unit  42  is a predetermined value, for example, “0.5 seconds”, it is judged whether the shutter key  9  is fully pressed at a time (step D 08 ). 
     Here, only when it is judged that the clocking value of the internal timer in the control unit  42  is below the predetermined value and that the shutter key  9  has been fully pressed at a time, the locked state of the AF is temporarily cancelled. The position of the focus lens is moved in accordance with the position of the zoom lens of the lens optical system  32  at the moment, and stop-down setting is performed in accordance with the locked AE value. Thus, photography is performed with a fixed focus allowing a fixed great depth of field to be obtained, and an obtained image is retained in a DRAM  41  (step D 09 ). 
     Subsequently, regardless of whether the photography has been performed with the fixed focus in step D 09 , a still image is captured in a state where photographing conditions based on the AF processing and AE processing remain locked to obtain image data (step D 10 ). 
     Next, it is judged whether or not the data on the still image reproduced with the fixed focus is retained in the DRAM  41  (step D 11 ). If it is not retained, the data on the still image captured with the autofocus alone is compressed and converted into a file in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step D 13 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step C 01  to again prepare for next photography. 
     On the other hand, when it is judged in step D 11  that the data on the still image reproduced with the fixed focus is retained in the DRAM  41 , both data on the still image obtained with the autofocus and the data on the still image obtained by the fixed focus in step D 09  are compressed and converted into files in the JPEG circuit  46 , and stored/saved on the internal memory  47  or the memory card  48  (step D 12 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step D 01  to again prepare for next photography. 
     Thus, proper time is set to judge time required for the operation of the shutter key  9  to detect a rapid full press of the shutter key  9 , thus obtaining a still image based on the fixed focus and a still image based on the autofocus. Therefore, even when the still image captured by the actuation of the autofocus function is out of focus or blurred due to a factor such as hand movement, it is highly likely that the still image captured with the fixed focus immediately before the autofocus photography is sufficiently vivid. This makes it possible to avoid a situation where a blurred image can only be obtained at a rare moment to press the shutter and ensuring that the still image focused on the desired subject is captured and stored. 
     Fifth Embodiment 
     A fifth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
       FIG. 8  shows contents of processing performed when a still image is captured in a photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step E 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step E 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step E 02 . The value of a distance to a subject is accurately measured, and the focal distance value is locked (step E 03 ). 
     In addition, a proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step E 04 ). Then, it is repeatedly judged whether or not the shutter key  9  has been further fully pressed (step E 05 ) or whether or not it is still half-pressed (step E 06 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step E 06 , and a return is made again to the processing in step E 01  concluding that the actual photography has not been reached. 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step E 05 . An output level of an acceleration sensor  51  at the moment is detected, and depending on whether or not a value thereof is above a certain value which makes it possible to judge in advance that hand movement has occurred, it is judged whether or not there is a possibility of the hand movement due to the full-press operation of the shutter key  9  (step E 07 ). 
     Here, only when it is judged that the output level of the acceleration sensor  51  is above a certain value and that there is a possibility of the hand movement, the locked state of the AF is temporarily cancelled. The position of the focus lens is moved in accordance with the position of the zoom lens of the lens optical system  32  at the moment, and stop-down setting is performed in accordance with the locked AE value. Thus, photography is performed with a fixed focus allowing a fixed great depth of field to be obtained, and an obtained image is retained in a DRAM  41  (step E 08 ). 
     Subsequently, regardless of whether or not the photography has been performed with the fixed focus in step E 08 , a still image is captured in a state where photographing conditions based on the AF processing and AE processing remain locked to obtain image data (step E 09 ). 
     Next, it is judged whether or not the data on the still image reproduced with the fixed focus is retained in the DRAM  41  (step E 10 ). If it is not retained, the data on the still image captured with the autofocus alone is compressed and converted into a file in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step E 12 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step E 01  to again prepare for next photography. 
     On the other hand, when it is judged in step E 10  that the data on the still image reproduced with the fixed focus is retained in the DRAM  41 , both data on the still image obtained with the autofocus and the data on the still image obtained by the fixed focus in step E 09  are compressed and converted into files in the JPEG circuit  46 , and stored/saved on the internal memory  47  or the memory card  48  (step E 11 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step E 01  to again prepare for next photography. 
     Thus, when the hand movement is detected from the output level of the acceleration sensor  51 , the still image based on the fixed focus and the still image based on the autofocus are obtained. Therefore, even when the still image based on the autofocus is blurred due to the hand movement, it is likely that the still image based on the fixed focus is not affected, thereby allowing an error in the photography to be erased and ensuring that the still image focused on the desired subject is captured and stored. 
     It is to be noted that in the embodiment described above, the acceleration sensor  51  is used to detect a state blurred by the hand movement. However, the present invention is not limited thereto, and a sensor such as a gyro sensor may be used instead. 
     Sixth Embodiment 
     A sixth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
     Furthermore, when photography is performed with this digital camera  1  using flash light emission, that is, when an automatic emission mode of a flash is set and a sufficient illumination for a subject can not be obtained without the flash light emission, or when a compulsory emission mode of the flash is set, pre-emission is conducted wherein the flash is caused to emit light before actual light emission of the flash in actual photography, and an amount of light emission in the actual light emission of the flash is corrected in accordance with an amount of light reflected from the subject. 
     Moreover, in this photographing mode, a user selects and sets in advance to perform photography with the fixed focus simultaneously with the pre-emission of the flash or to perform photography with the fixed focus prior to the pre-emission (without the flash light emission). 
       FIG. 9  shows contents of processing performed when a still image is captured in the photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step F 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step F 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step F 02 , and the value of a distance to the subject is again accurately measured by the AF processing, and the focal distance value is locked (step F 03 ). A proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step F 04 ). 
     Subsequently, it is judged whether or not to irradiate auxiliary light by the flash light emission during photography in accordance with a flash mode set at this point (step F 05 ). 
     This judgment is made, if the set flash mode is the automatic emission mode, depending on whether or not the exposure value locked in the AE processing is at such a level that requires the flash light emission, or depending on whether or not the flash mode is set to the compulsory emission mode, or depending on whether the flash mode is not set to an emission prohibited mode. As a result, it is judged whether or not to perform photography with the irradiation of the auxiliary light by the flash light emission. When it is determined to perform the photography without the flash light emission, an ordinary photographing operation will be performed which is not associated with the present embodiment, so that this operation is not described below. 
     Furthermore, when the flash mode is the automatic emission mode and the exposure value is at such a level that requires the flash light emission, or when the flash mode is set to the compulsory emission mode and the flash light emission is therefore performed, this is judged in step F 05 . Next, it is repeatedly judged whether or not the shutter key  9  is fully pressed (step F 06 ) or whether or not it is still half-pressed (step F 07 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step F 07 , and a return is made again to the processing in step F 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step F 06 . Then, it is judged whether or not it is selected and set to capture a still image with the fixed focus simultaneously with the pre-emission of a flash light emitting unit  6  (step F 08 ). 
     Here, when it is judged that it is selected and set to capture a still image simultaneously with the pre-emission, the locked state of the AF processing is once cancelled, and a focus lens in a lens optical system  32  is moved to a position which achieves a fixed focus corresponding to a focal distance at that point. In addition, a flash light emitting unit  6  is caused to perform pre-emission by a flash drive section  52  in a light emission amount corresponding to the locking of the AE processing, and synchronously with this, a still image is captured with the fixed focus to obtain image data (step F 09 ). At this point, an amount of reflected light for the amount of light emitted by the flash light emitting unit  6  is calculated from the obtained image data. 
     Furthermore, when it is judged that it is selected and set not to perform photography simultaneously with the pre-emission in step F 08 , the locked state of the AF processing is once cancelled, and the focus lens in the lens optical system  32  is moved to the position which achieves the fixed focus corresponding to the focal distance at that point. In addition, the photography with the fixed focus is performed in accordance with the locking of the AE processing without the pre-emission of the flash light emitting unit  6  to obtain image data, and the obtained image data is retained in a DRAM  41  (step F 10 ). 
     Subsequently, the flash light emitting unit  6  is caused to perform the pre-emission by the flash drive section  52 , and an amount of reflected light for the amount of light emitted by the flash light emitting unit  6  is calculated (step F 11 ). 
     After the processing in step F 09  or F 11 , the exposure value locked in the AE processing is corrected by the pre-emission in accordance with the calculated amount of reflected light, and the focus lens in the lens optical system  32  is returned to the lock position in the AF processing obtained in step F 03 , thus performing the actual photography for a still image based on the AF processing while causing the flash light emitting unit  6  to perform the actual light emission by the flash drive section  52  (step F 12 ). 
     Then, both obtained data on the still image in the actual photography in accordance the AF processing and data on the still image obtained by the fixed focus in step F 09  or F 10  immediately before the AF processing are compressed and converted into files in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step F 13 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step F 01  to again prepare for next photography. 
     Thus, when flash photography is performed using the flash light emitting unit  6 , the photography with the fixed focus is performed during or off the pre-emission in accordance with the selection and setting of the user, and the image is stored/saved to be paired with the still image based on the autofocus captured during the actual photography after the pre-emission. Therefore, even when the still image captured by the actuation of the autofocus function is out of focus or blurred due to a factor such as hand movement, it is highly likely that the still image captured with the fixed focus by use of the pre-emission immediately before the autofocus photography is sufficiently vivid. This makes it possible to avoid a situation where a blurred image can only be obtained at a rare moment to press the shutter and ensuring that the still image focused on the desired subject is captured and stored. 
     In addition, the still image is captured with the fixed focus during or off the pre-emission in accordance with the selection and setting of the user, so that it is possible to obtain a still image with the fixed focus in such a manner as to accurately reflect the intent of the user. 
     Seventh Embodiment 
     A seventh embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
     Moreover, this digital camera  1  allows photography for a still image based on a manual focus (referred to as “MF” in the drawing) to focus at an arbitrary set distance value, in addition to the photography for a still image based on the autofocus and the photography for a still image based on the fixed focus. When a user specifies the photography based on the manual focus, a still image is captured on the basis of a focal distance value set in a range from a shortest photographing distance to infinity in which a lens optical system  32  can focus. 
       FIG. 10  shows contents of processing performed when a still image is captured in the photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step G 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step G 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step G 02 , and the value of a distance to the subject is again accurately measured by the AF processing, and the focal distance value is locked (step G 03 ). A proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step G 04 ). 
     Subsequently, it is repeatedly judged whether or not the shutter key  9  is fully pressed (step G 05 ) or whether or not it is still half-pressed (step G 06 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step G 06 , and a return is made again to the processing in step G 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step G 06 . Then, it is judged whether or not the manual focus has been previously specified (step G 07 ). 
     Here, only when it is judged that the manual focus has been specified, the locked state of the AF processing is once cancelled, and a focus lens in the lens optical system  32  is moved to a specified in-focus position for the manual focus. Thus, a still image is captured to obtain image data, and the obtained image data is retained in a DRAM  41  (step G 08 ). 
     Subsequently, the focus lens in the lens optical system  32  is moved to a position which achieves the fixed focus corresponding to the focal distance at that point. Thus, a still image based on the fixed focus is captured to obtain image data, and the obtained image data is retained in the DRAM  41  (step G 09 ). 
     Furthermore, the focus lens in the lens optical system  32  is returned to the lock position in the AF processing obtained in step G 03 , thus performing the actual photography for a still image based on the AF processing (step G 10 ). 
     Thus, obtained data on the still image in accordance the AF processing and data on the still image obtained by the fixed focus in step G 09  immediately before the AF processing, as well as the image data when a still image has been captured with the manual focus in step G 08 , are compressed and converted into files in a JPEG circuit  46 , and stored/saved in a set on an internal memory  47  or a memory card  48  (step G 11 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step G 01  to again prepare for next photography. 
     Thus, the setting of the manual focus including the infinity specified by the user is utilized, so that when the manual focus is set, photography for a still image at a manual focus position and photography for a still image with the fixed focus are performed prior to photography for a still image with the autofocus, and image data in these operations are stored/saved in a set. Therefore, even when the still image captured by the actuation of the autofocus function is out of focus or blurred due to a factor such as hand movement, it is highly likely that the still image captured in the manual focus setting and the still image captured with the fixed focus by use of the pre-emission immediately before the autofocus photography are sufficiently vivid. This makes it possible to avoid a situation where a blurred image can only be obtained at a rare moment to press the shutter and ensuring that the still image accurately reflecting the photographic intent of the user is captured and stored. 
     It is to be noted that in the embodiment described above, when the manual focus is set by the user, a maximum of three still images in total is captured including a still image based on the manual focus, a still image based on the fixed focus and a still image based on the autofocus, and these are stored in a set. However, the present invention is not limited thereto, a still image may be captured at an in-focus position set by the manual focus instead of the still image obtained with the autofocus, and data on this still image may be stored to be paired with the data on the still image obtained with the autofocus. 
     In addition, the photography with the fixed focus in step G 09  and the AF photography in step G 10  may be performed in reverse order. 
     Eighth Embodiment 
     An eighth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with bracketing described later is performed in the following manner: one of the various photographing conditions including an exposure value in the digital camera is selected, such as an in-focus position, a white balance, chroma, sharpness or contrast, and its variable step width and a total number of images captured are specified, thereby sequentially capturing still images under different photographing conditions in stages. 
     For example, in a case where the exposure value is specified as a photographing condition to execute a representative bracketing function heretofore been referred to as autobracket, suppose that, for example, the variable step width is “½ [EV]” and the total number of images captured is “five”. Then, still images will be sequentially captured whose exposures are corrected in five stages in total: “−1.0 [EV]”, “−0.5 [EV]”, “0 [EV]” “+0.5 [EV]”, and “+1.0 [EV]” provided that a proper exposure value obtained in the AE processing is “0 [EV]”. 
     Thus, in the present embodiment, a user arbitrarily specifies the photographing condition as required, and its variable step width and the total number of images captured are specified, such that the bracketing photography is performed to capture still images while changing the photographing conditions in stages for the number of images sequentially captured. 
       FIG. 11  shows contents of processing performed when a still image is captured in the photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step H 01 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step H 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step H 02 , and the value of a distance to a subject is again accurately measured by the AF processing, and the focal distance value is locked (step H 03 ). A proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step H 04 ). 
     Subsequently, it is repeatedly judged whether or not the shutter key  9  has been further fully pressed (step H 05 ) or whether or not it is still half-pressed (step H 06 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step H 06 , and a return is made again to the processing in step H 01 . 
     Furthermore, if the shutter key  9  is fully pressed from a state in which the AF value and AE value are locked, this is judged in step H 05 . A still image is immediately captured from a state in which the states of the AF and AE are locked, and obtained data are retained in a DRAM  41  (step H 07 ). 
     Next, it is judged whether or not the bracketing has been previously specified by the user (step H 08 ). Only when it is judged that the bracketing has been specified, still images under the different photographing conditions are sequentially captured in stages in accordance with the specified contents of bracketing, and obtained data are retained in a DRAM  41  (step H 09 ). 
     Then, after the photography has entirely terminated, data on all the still images retained in the DRAM  41  are compressed and converted into files in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  in a set if necessary (step H 10 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step H 01  to again prepare for next photography. 
     Thus, the photography in accordance with the bracketing contents set by the user as required is performed together with the photography with the autofocus, and the image data are stored/saved in a set. Therefore, even when the still images captured by the actuation of the autofocus function result in out-of-focus images or have contents different from the intent of the user, it is possible to obtain still images suited to the intent of the user with a high probability. 
     Ninth Embodiment 
     A ninth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of the zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
     Moreover, in scene program photography described later, one is selected from a plurality of kinds for which settings of photographing conditions have been preprogrammed so that photography can be automatically performed with setting optimum for a scene to be photographed in a photographing mode. For example, one is selected from “person”, “scenery”, “scenery and person”, “close-up of person”, “close-up of bust of person”, “two persons”, “child”, “candlelight and person”, “party”, “pet”, “close-up of flower”, “bright green”, “autumn leaves”, “smooth water flow”, “stopped spray”, “building”, “cityscape”, “blue sky”, “bright sand beach and sea”, “setting sun”, “night scenery”, “night scene and person”, “firework”, “food”, “characters”, etc. 
     Specific set contents of the photographing condition include examples as follows. For “bright green”, hard sharpness, higher chroma and color emphasis of green are set. Alternatively, for “candlelight and person”, soft sharpness, white balance of sunlight, a lower shutter speed and a flash mode of red-eye reduction are set. 
     Depending on the selected contents for the scene program photography, it is highly likely that the autofocus operation is difficult and photography results in a failure, for example, in a case of a moving subject such as “child”, “pet” and “stopped spray”, or in a case where insufficient illumination is anticipated as in “candlelight and person”, “party” and “night scene”. 
     Therefore, photography with the fixed focus is automatically utilized as needed in addition to the autofocus photography to adapt to the selected content for the scene program photography. 
       FIG. 12  shows contents of processing performed when any one of the contents for the scene program photography is selected and thus a still image is captured in the photographing mode. Initially, simple 
     AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step  101 ), and also judging whether or not the shutter key  9  of a key input section  49  has been half-pressed (step  102 ). Such processing is repeatedly performed to wait for the shutter key  9  to be in a half-pressed state. 
     Thus, if the shutter key  9  is half-pressed, this is judged in step  102 , and the value of a distance to a subject is accurately measured by the AF processing as required, and the focal distance value is locked (step  103 ). A proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked as required (step  104 ). 
     It is to be noted that as indicated by “*1” and “*2” in the drawing, the AF processing and the AE processing are executed as required depending on the content for the scene program photography selected at the moment. This includes a case where the AF processing and the AE processing are not performed for some contents and a case where results of the processing are corrected if performed. For example, when “night scene” is selected, the in-focus position is unconditionally set to infinity. Alternatively, for “bright sand beach and sea”, exposure is corrected to a positive side. 
     Subsequently, it is repeatedly judged whether or not the shutter key  9  has been further fully pressed (step  105 ) or whether or not it is still half-pressed (step  106 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-press operation for the shutter key  9  is cancelled, this is judged in step  106 , and a return is made again to the processing in step  101 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step  106 . Then, it is judged whether or not the scene program photography selected at the moment is particular one that uses photography with the fixed focus together (step  107 ). 
     Here, when it is judged that the particular scene program photography is selected, a still image is captured in accordance with the set contents of the selected photographing condition, and obtained data is retained in a DRAM  41  (step  108 ). Then, the position of a focus lens of a lens optical system  32  is suitably moved in accordance with the position of a zoom lens of the lens optical system  32  selected at the moment, and thus a still image is also captured with the fixed focus, and obtained data is retained in the DRAM  41  (step  109 ). 
     In the case where the photography with the fixed focus is performed, not only the position of the zoom lens of the lens optical system  32  but also the position of the focus lens is moved considering the contents for the scene program photography only when perfect pan focus effects can not be obtained. For example, the position is moved closer to the infinity side for “scenery”, “night scene”, etc, whereas it is moved closer to a shortest photographing distance side for “pet”, “close-up of flower”, etc. In this way, an in-focus range may be moved back and forth and set in accordance with the distance from the target subject. 
     Then, after the photography corresponding to the operation of the shutter key  9  has terminated, data on the two still images retained in the DRAM  41  are compressed and converted into files in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  in a set (step  110 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step  101  to again prepare for next photography. 
     Moreover, when it is judged in step  107  that the scene program photography selected at the moment is not the particular one that uses photography with the fixed focus together, a still image is captured in accordance with the set contents of the selected photographing condition, and obtained data is retained in the DRAM  41  (step Ill). Then, considering that the photography corresponding to the operation of the shutter key  9  has terminated, data on the still image retained in the DRAM  41  is immediately compressed and converted into a file in the JPEG circuit  46 , and solely stored/saved on the internal memory  47  or the memory card  48  (step  112 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step  101  to again prepare for next photography. 
     Thus, the still image based on the fixed focus is captured together when considered necessary in accordance with the content selected from a plurality of prepared contents for the scene program photography. Therefore, even when the still image based on the autofocus is out of focus, it is highly likely that the still image captured with the fixed focus as required is in focus. This makes it possible to capture and store a still image focused on the desired subject with a high probability without particularly increasing in size and complicating the apparatus and circuits. 
     Tenth Embodiment 
     A tenth embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 1B  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that in a digital camera  1 , a shutter key  9  has a two-stage operation stroke as in other typical cameras, and a photographing operation is executed on the basis of an operation logic as follows: at a first step, autofocus (AF) processing and automatic exposure (AE) processing are performed in a state generally called half press where the shutter key is pressed down to about half of a full stroke, and individual values in the processing are locked; and at a second step, actual photography is executed with the above AF value and AE value in an operation with a full stroke generally called full press. 
     In addition, the shutter key  9  in a key input section  49  not only has the two-stage operation stroke but also has a touch sensor function to detect the touch of a hand/finger of a user on a surface. 
     Furthermore, photography with a fixed focus described later (referred to as “PF photography” in the drawing) means photography performed by so-called “stop-down” wherein a focus lens is moved to a predetermined position and an aperture (F) value and a shutter speed are read and set on the basis of a lookup table fixedly prestored in a ROM within a control unit  42  in accordance with the focal distance position of a zoom lens selected at the moment, an ISO film speed set at the moment and an AE value (light amount), thereby performing photography by obtaining a state called pan focus (PF) where a depth of field practically covering the whole distance is obtained, or by obtaining a fixed great depth of field close to the above-mentioned depth of field. 
       FIG. 13  shows contents of processing performed when a still image is captured in the photographing mode. Initially, simple AF processing and AE processing are executed within a predetermined frame rate at the moment, for example, 30 [frames/second], and a CCD  33  is sequentially driven at a high shutter speed considering the frame rate, thereby maintaining a through image display state in which contents imaged by the CCD  33  are displayed on a display section  21  (step J 01 ), and also judging whether or not the hand/finger of the user has touched the surface of the shutter key  9  of a key input section  49  (step J 02 ). Such processing is repeatedly performed to wait for the shutter key  9  to be touched. 
     Thus, if the shutter key  9  is touched, this is judged in step J 02 . The focus lens of the lens optical system  32  is moved in accordance with the focal distance and the AE value corresponding to the position of the zoom lens of the lens optical system  32  at the moment, so that photography is performed with a fixed focus allowing a fixed great depth of field to be obtained, and an obtained image is retained in a DRAM (step J 03 ). 
     Subsequently, it is repeatedly judged whether or not the shutter key  9  is half-pressed (step I 04 ) or whether or not the surface of the shutter key  9  is still touched (step I 05 ), thus waiting for the shutter key  9  to be half-pressed or waiting for the touched state of the shutter key  9  to be cancelled. 
     Here, when the touched state of the shutter key  9  is cancelled, this is judged in step J 05 , concluding that the operation of the shutter key  9  has not been reached. Data on the still image retained in the DRAM  41  at the moment and obtained by the photography based on the fixed focus in step J 03  is deleted for nullification (step J 06 ), and a return is made again to the processing in step J 01 . 
     Furthermore, when it is judged in step J 04  that the shutter key  9  is half-pressed, the value of a distance to a subject is accurately measured in accordance with the operation, and the focal distance value is locked (step J 07 ). 
     Then, a proper exposure value is obtained from a state in which the autofocus position is locked, and an aperture value and a shutter speed are set from the exposure value and locked (step J 08 ). Thus, it is repeatedly judged whether or not the shutter key  9  is fully pressed (step J 09 ) or whether or not it is still half-pressed (step J 10 ), thus waiting for the shutter key  9  to be fully pressed while states of the AF and AE are locked or waiting for the half-pressed state to be cancelled. 
     Here, when the half-pressed state of the shutter lens  9  is cancelled, this is judged in step J 10 , concluding that the full-press operation of the shutter key  9  has not been reached. Data on the still image retained in the DRAM  41  and the moment and obtained by the photography based on the fixed focus in step J 03  is deleted for nullification (step J 11 ), and a return is made again to the processing in step J 01 . 
     Furthermore, if the shutter key  9  is fully pressed from the state in which the AF value and AE value are locked, this is judged in step J 09 , and a still image is captured in a state where photographing conditions based on a autofocus function remain locked to obtain image data (step J 12 ). 
     Subsequently, both data on the still image obtained with the autofocus and data on the still image obtained by the fixed focus in step J 03  are compressed and converted into files in a JPEG circuit  46 , and stored/saved on an internal memory  47  or a memory card  48  (step J 13 ). A series of processes regarding the photography thus terminates, and a return is made to the processing in step J 01  to again prepare for next photography. 
     Thus, even when the still image captured by the actuation of the autofocus function is out of focus or blurred due to a factor such as hand movement, it is highly likely that the still image captured with the fixed focus immediately before the autofocus photography is sufficiently vivid. This makes it possible to capture and store a still image focused on the desired subject with a high probability without particularly increasing in size and complicating the apparatus and circuits. 
     In addition, the still image based on the fixed focus is captured at the point where the shutter key  9  is touched, and the still image based on the autofocus is captured in the subsequent full-press operation, thereby allowing the user to obtain the still image based on the fixed focus without feeling discomfort. 
     Furthermore, when the actual photography by the autofocus function has not been reached, the data on the image based on the fixed focus captured earlier is destroyed, and it is therefore ensured that unnecessary waste of limited storage capacity in the internal memory  47  or the memory card  48  can be avoided. 
     Eleventh Embodiment 
     An eleventh embodiment in which the present invention is applied to a digital camera will hereinafter be described in reference to the drawings. 
     It is to be noted that an external configuration of the digital camera is basically similar to that in  FIG. 1A  and  FIG. 13  and a functional configuration of an electronic circuit is basically similar to that in  FIG. 2 , so that the same numerals are used for the same parts and those parts are not shown and described. 
     Now, an operation in this embodiment will be described. 
     It is to be noted that data on sequentially captured two still images, that is, data on the still image obtained with an autofocus and data on the still image captured with a fixed focus are stored in pairs in a data folder of the same name in an internal memory  47  or a memory card  48 . 
     In this case, for image data files of the still images stored in pairs in the data folder, file names such as “200309080001a.jpg” “200309080001b.jpg” are set and stored in the data folder whose name is “200309080001”. The two data files can be recognized as a pair from the file name, and differentiated. 
     In the above-mentioned data folder name itself and the file names, “200309080001” indicates that the photography was performed on “2003(year)09(month)08(date)” “0001(first)”. Photographing condition data additionally set to the actual image data in each file include typical information such as photographing date and time, the ISO film speed, an image size, a shutter speed, an aperture (F) value and a while balance, as well as identification information on whether the photography was conducted by the actuation of the autofocus function or by the fixed focus. 
     Therefore, it is possible not only to identify, owing to the file names of the stored data files, that the two still images are paired and were sequentially captured but also to know from the photographing condition data whether the photography was conducted by the actuation of the autofocus function or by the fixed focus. 
       FIG. 14  shows contents of processing of, for example, rewriting an order of priority among a plurality of data folders mainly storing paired image data in a state where a reproduction mode as a basic mode is selected. Initially, among a plurality of image data folders stored in an internal memory  47  or a memory card  48 , the latest folder, that is, the folder having the highest value of a numerical portion in the data folder name is selected (step K 01 ). 
     Next, in the selected data folder, the data file of the still image (.jpg (=JPEG)) whose name ends with “a” is selected as one with a higher order of priority (step K 02 ). 
     Then, the identification information indicating whether the photography was performed by the actuation of the autofocus function or by the fixed focus is read from the photographing condition data additionally set in the selected image data file of the still image, and the contents of the information is judged (step K 03 ). 
     When the photography is judged to have been performed by the actuation of the autofocus function, corresponding image data is read and expanded, and then displayed on a display section  21  in a state where characters “AF” are superposed at an upper left end in a screen as shown in  FIG. 4B  (step K 04 ). 
     Furthermore, when the photography was not performed by the actuation of the autofocus function but performed with the fixed focus, corresponding image data is read and extracted, and then displayed on the display section  21  in a state where characters “PF” are superposed at the upper left end in the screen as shown in  FIG. 4A  (step K 05 ). 
     It is repeatedly judged whether or not any key operation is made by a key input section  49  while maintaining the state of image display in step K 04  or K 05 , thereby waiting for a corresponding key operation to be made (step K 06 ). 
     If any key operation is performed, this is judged in step K 06 . Then, it is judged whether or not this key operation has been performed to change the data folder, more specifically, for example, whether or not this operation has been performed by the operation of a leftward key or a rightward key of a ring key  14  (step K 07 ). 
     Here, if it is judged that the key operation has been performed to change the data folder, processing will be performed to change the data folder in accordance with the contents of the key operation (step K 10 ), and a return is made to the processing in step K 02  to display image data with a higher order of priority in the changed data folder. 
     Moreover, if it is judged in step K 07  that the key operation has not been performed to change the data folder, it will then be judged whether the key operation has been performed to change the order of priority of the images, more specifically, for example, whether or not a menu key  16  has been operated and a “replace” menu has been subsequently selected (step K 08 ). 
     Here, if it is judged that the key operation has been performed to change the order of priority of the images, it will then be judged whether or not there is, in the same data folder, candidate image data for replacement, that is, image data whose file name ends with “b” (step K 11 ). 
     At this point, only when it is judged that there is the candidate image data for replacement, the file name of the image data is set to be rewritten for replacement processing (step K 12 ), and a return is made to the processing in step K 02  to display the image data whose order of priority has become higher owing to the changed contents. 
     Thus, when the still image with a higher order of priority can not be enjoyed due to blurring or the like, and the other still image of the pair (with a lower order of priority) is clearer, the order of priority influencing the display can be easily rewritten by the key operation to replace the image data. 
     Furthermore, if it is judged in step K 11  that there is not any candidate image data for replacement in the same data folder, this instruction for replacement is processed as invalid (NOP), and a return is made to the processing in step K 02 . 
     Moreover, if it is judged in step K 08  that the key operation has not been performed to change the order of priority of the images, it will then be judged whether or not the key operation has not been performed to delete the image data displayed at the moment, more specifically, for example, whether or not the menu key  16  has been operated and a “delete” menu has been subsequently selected (step K 09 ). 
     Here, if it is judged that the key operation has been performed to delete the image, a guide massage is displayed on the display section  21  to indicate that the image can not be restored once deleted and to confirm the deletion (step K 13 ), thus waiting for the confirmation operation to be performed (step K 14 ). 
     Then, at the point where the confirmation operation is judged to have been made, the image data file for the still image is set to be deleted from the data folder. In addition, the inside of the data folder is organized, for example, the file names of the remaining data on the still images are adjusted, or the data folder itself is set to be deleted if no image data remains in the data folder (step K 15 ). Then, a return is made again to the processing in step K 02 . 
     It is to be noted that if it is judged in step K 09  that the key operation has not been performed to delete the image data displayed at the moment, processing corresponding to the contents of the key operation is performed. However, this is not explained in the present embodiment, and this key operation is expressed as invalid in the drawing. 
     In this way, the still images sequentially captured by the actuation of the autofocus function and the still images based on the fixed focus are stored in pairs in the internal memory  47  or the memory card  48 , and one with a higher order of priority among these still image is selected and displayed. Moreover, the order of priority can be arbitrarily rewritten in the simple key operation. This makes it possible to read and display a better image reflecting the intent of the user in the simple key operation. 
     It is to be noted that the data on the two still images in pairs are stored on the internal memory  47  or the memory card  48  in a state contained in the data folder of the same name in the eleventh embodiment described above. However, the present invention is not limited thereto, and the paired image data may be stored in a place other than the data folder. 
     Moreover, all the first to eleventh embodiments described above concern the cases appropriate for the digital camera. However, the present invention is not limited thereto, and is also applicable to other small-sized electronic devices such as mobile telephones and personal digital assistants (PDAs) having a camera function capable of autofocus by the movement of the focus lens in the lens optical system. 
     In addition, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit thereof. 
     Furthermore, the embodiments described above include various stages of the invention, and various inventions can be extracted by proper combinations of a plurality of disclosed requirements. For example, although some of all the requirements disclosed in the embodiments are deleted, it is still possible to solve at least one of the problems described in the section of “Description of the Related Art”, and at least one of the effects described in the section of “SUMMARY OF THE INVENTION”. In this case, a configuration in which those requirements are deleted can be extracted as an invention.