Abstract:
A determination is made as to whether or not the magnification set for image sensing is greater than the upper limit of the optical finder. When the set magnification is greater, the original image is subjected to a thinness process, the LCD is automatically turned ON, and the image is displayed. When using electronic zoom, an image of the photographic object corresponding to the effective image sensing magnification is displayed on the LCD  10,  thereby avoiding impairing the compactness of the digital camera allowing easy confirmation of the photographic object, and allowing easy framing without providing a large optical finder.

Description:
[0001]    This application is based on Patent Application No. 11-354565 filed in Japan, the content of which is hereby incorporated by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a digital camera provided with a zoomable optical finder and electronic finder having an electronic zoom function. The present invention further relates to a recording medium for recording programs readable by the digital camera.  
           [0004]    2. Description of the Related Art  
           [0005]    Most digital cameras have a finder for electrically displaying an image via liquid crystal device (LCD) or the like (hereinafter referred to as “electronic finder”). However, in such digital cameras, the electronic finder juxtaposed with an optical finder is optionally turned ON/OFF via a switch in order to prevent battery power consumption.  
           [0006]    Digital cameras are known which are provided with a electronic zoom function of about 2x without deterioration of image quality in order to enlarge a photographic object while maintaining the compactness of the camera. Since the field of view of the optical finder does not match the actual photographic range during electronic zooming, a field of view frame is displayed in the optical finder during electronic zooming.  
           [0007]    Although it is possible to associate the field of view of the optical finder with the actual photographic range in this way, a disadvantage arises in that it is difficult to confirm a photographic subject simply by displaying the photographic range with a simple field of view frame because the subject cannot be optically displayed in enlargement.  
           [0008]    Japanese Laid-Open Patent Application No. H6-189173 discloses a digital camera wherein a finder optical system zooms in response to electronic zooming. This application discloses a digital camera provided with an actual zoom function of up to 6x by using together a 3x optical zoom and a 2x electronic zoom, thereby having an optical finder with a 6x zoom ratio corresponding to the combined 6x zoom ratio.  
           [0009]    According to this art, however, although the photographic subject is easily confirmed and framing is easily accomplished, the optical finder is provided a zoom function corresponding to the effective zoom function. Accordingly, the optical finder is larger and heavier, and disadvantageously interferes with the compactness of the camera.  
           [0010]    An object of the present invention is to eliminate the disadvantages of the conventional art by providing a digital camera and recording medium allowing easy confirmation of a photographic object and easy framing without interfering with the compactness of the digital camera.  
         SUMMARY OF THE INVENTION  
         [0011]    These objects are attained by the digital camera of the present invention comprising: an optical finder for optically viewing a photographic object; an electronic finder for electronically displaying a photographic object; an operation member for performing an electronic zoom; a switching member for switching between an activated state and a deactivated state of the electronic finder; and a controller for setting the electronic finder to the activated state forcedly when the electronic zoom is performed by the operation member.  
           [0012]    These objects are further attained by another digital camera of the present invention comprising: an optical finder for optically viewing a photographic object; an electronic finder for electronically displaying a photographic object; an operation member for performing an electronic zoom; a switching member for switching between an activated state and a deactivated state of the electronic finder; a zooming lens for image sensing; and a controller for setting the electronic finder to the activated state forcedly when an effective magnification of one or both an optical zoom of said zoom lens or said electronic zoom exceeds a magnification range of said optical finder.  
           [0013]    These objects are further attained by another digital camera of the present invention comprising: an optical finder for optically viewing a photographic object; an electronic finder for electronically displaying a photographic object; an operation member for performing an electronic zoom; a switching member for switching between an activated state and a deactivated state of the electronic finder; a setter for setting a magnification for image sensing when the digital camera is activated; and a controller for setting said electronic finder to the activated state when said magnification is determined to be outside a magnification range of the optical finder.  
           [0014]    These objects are further attained by another digital camera of the present invention comprising: an optical finder for optically viewing a photographic object; an electronic finder for electronically displaying a photographic object; an operation member for performing an electronic zoom; a setter for setting a magnification for image sensing when the digital camera is activated; and an indicator for indicating a warning when said magnification is outside a magnification range of the optical finder.  
           [0015]    These objects are further attained by A recording medium in which a program to be executed by the digital camera having an optical finder for optically viewing a photographic object, an electronic finder for electronically displaying a photographic object, an operation member for performing an electronic zoom, and a switching member for switching between an activated state and a deactivated state of the electronic finder is recorded and which can be read by a computer, said program implementing: performing the electronic zoom by said operation member; and setting said electronic finder to the activated state forcedly when the electronic zoom is performed.  
       
    
    
     BRIEF DESCRIPTION OF THE DSRAWINGS  
       [0016]    In the following description, like parts are designated by like reference numbers throughout the several drawings.  
         [0017]    [0017]FIG. 1 is a front view of a digital camera of an embodiment of the present invention;  
         [0018]    [0018]FIG. 2 is a back view of a digital camera of an embodiment of the present invention;  
         [0019]    [0019]FIG. 3 is a side view of a digital camera of an embodiment of the present invention;  
         [0020]    [0020]FIG. 4 is a bottom view of a digital camera of an embodiment of the present invention;  
         [0021]    [0021]FIG. 5 is a block diagram showing the internal structure of the digital camera of an embodiment of the present invention;  
         [0022]    [0022]FIG. 6 shows the internal structure of the optical finder;  
         [0023]    [0023]FIG. 7 is a block diagram showing the structure of the image processor;  
         [0024]    [0024]FIG. 8 shows the condition of the electronic zoom process;  
         [0025]    [0025]FIG. 9 is a flow chart showing the processing sequence from power ON to power OFF;  
         [0026]    [0026]FIG. 10 is a flow chart showing the initialization process sequence;  
         [0027]    [0027]FIG. 11 is a flow chart showing the zoom process sequence during the photography standby;  
         [0028]    [0028]FIG. 12 is a flow chart showing the process of LCD automatic display control;  
         [0029]    [0029]FIG. 13 is a flow chart showing the LCD ON/OFF control process sequence;  
         [0030]    [0030]FIG. 14 is a flow chart showing the warning LED control process sequence; and  
         [0031]    [0031]FIG. 15 shows a modification of the warning means.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    The preferred embodiments of the present invention are described hereinafter with reference to the accompanying drawings.  
         [0033]    [0033]FIGS. 1 through 4 respectively show a front view, back view, side view, and bottom view of a digital camera  1  of an embodiment of the present invention. FIG. 5 is a block diagram showing the internal structure of the digital camera  1 .  
         [0034]    The digital camera  1  comprises a box-like camera body  2 , and a rectangular image sensing unit  3  (indicated by the thick lines in FIGS. 1, 2, and  4 ) as shown in FIG. 1. The image sensing unit  3  has a macro function zoom lens  301  acting as a taking lens, and is provided with an image sensing circuit  302  having a CCD  303  (refer to FIG. 5) acting as a ½ inch size CCD color area sensor disposed at a suitable position behind the zoom lens  301 . The zoom lens  301  has a focal length of 7 mm in the wide state and 21 mm in the telecentric state, and has a zoom ratio of 3×. The digital camera  1  is capable of a maximum 6x zoom photography via an electronic zoom function described later.  
         [0035]    A light adjusting control circuit  304  having a light adjusting control sensor  305  for receiving the reflected light of the flash from the photographic object is provided at a suitable location within the image sensing unit  3  similar to a camera using silver halide film. In addition, a distance measuring sensor  306  for measuring the distance to a photographic object and an optical finder  31  are provided at suitable locations within the image sensing unit  3 . The internal structure of the optical finder  31  is described later.  
         [0036]    On the front surface of the camera body  2  is provided a grip  4  on the left end and a built-in flash  5  on the top center, and a shutter button  8  is provided on the top surface, as shown in FIG. 1.  
         [0037]    On the back surface of the camera body  2  is provided an LCD  10  as a photographic image monitor display (equivalent to a viewfinder), and for displaying the recorded images at the approximate center of the back surface as shown in FIG. 2. The LCD  10  is equivalent to an electronic viewfinder. Below the LCD  10  are provided key switches  221 - 226  for operating the digital camera  1 , and a power switch  227 . On the left side of the power switch  227  are arranged an LED  228  which lights when the power is ON, and an LED  229  which displays while a memory card is being accessed.  
         [0038]    Also on the back surface of the camera body  2  is a mode setting switch  14  for selecting among [photographic mode], [reproduction mode], and [preference mode] (refer to FIG. 2). The photographic mode is used for taking photographs. The reproduction mode is a mode for reproducing a photographed image recorded on a memory card and displaying the image on the LCD  10 . The preference mode is a mode for settings of various types by selecting a desired item from among display items (setting items). The operations in each mode are described later.  
         [0039]    The mode setting switch  14  is a contact point slide switch and sets the photographic mode when at the bottom, sets the reproduction mode at the center, and sets the preference mode at the top, as shown in FIG. 2.  
         [0040]    A 4-point switch  230  is provided on the right side of the back surface of the camera. In the photographic mode, a zoom motor  307  (refer to FIG. 5) drives the zoom lens  301  for zooming by pressing the buttons  231  and  232 . The zoom lens  301  is driven to the wide side when button  231  is pressed, and driven to the telecentric side when the button  232  is pressed.  
         [0041]    On the back of the image sensing unit  3  are provided an LCD button  321  for turning ON and OFF the LCD  10 , and a macro button  322 . When the LCD button  321  is pressed, the LCD display is switched ON or OFF. For example, during photography using only the optical finder  31 , the LCD display is switched OFF to conserve power. When the macro button  322  is pressed during macro photography, an AF motor  308  (refer to FIG. 5) is driven to place the zoom lens  301  in the macro photography enabled state.  
         [0042]    On the side of the camera body  2  is provided a pin unit  235 , as shown in FIG. 3. The pin unit  235  is provided with a DC input pin  235   a,  and a video-out pin  235   b  for outputting the content displayed on the LCD  10  to an external video monitor.  
         [0043]    On the bottom surface of the camera body  2  are provided a battery compartment  18  for loading a battery, and a card compartment  17 , as shown in FIG. 4. The card compartment  17  has a slot-shaped insertion opening used for inserting a memory card  91  within the camera body  2  to allow writing and reading of image data to/from the memory card  91 . Both compartments can be opened and closed using a clam-shell type door. FIG. 4 shows an example with a memory card  91  installed in the card compartment  17 .  
         [0044]    In the digital camera  1 , four AA-size dry cell batteries are installed in the battery compartment  18 , and connected in series as to form the power source battery  236  (refer to FIG. 5) which is used as the drive source. Of course, electric power also may be supplied from an adapter using the DC input pin  235   a  shown in FIG. 4.  
         [0045]    The bottom surface is also provided with release lever  19  for releasing the connection between the image sensing unit  3  and the camera body  2  which are connected by a connector and key-like connecting member.  
         [0046]    The internal structure of the image sensing unit  3  is described below with reference to FIG. 5.  
         [0047]    The image sensing circuit  302  photoelectrically converts an optical image of the photographic object formed on the CCD  303  by the zoom lens  301  using the CCD  303 , and outputs the image as red (R), green (G), blue (B) color component image signals (signals comprising a signal series of pixel signals of the light received by each pixel).  
         [0048]    Since the diaphragm is fixed in the digital camera  1 , exposure control in the image sensing unit  3  is accomplished by regulating the amount of exposure light of the CCD  303  (i.e., the load accumulation time of the CCD  303  corresponding to shutter speed). When a suitable shutter speed cannot be set when the photographic object luminance is a low luminance, unsuitable exposure due to insufficient exposure light can be corrected by adjusting the level of the image signal output from the CCD  303 . That is, during times of low luminance, exposure can be controlled by combining shutter speed and gain adjustment. The image signal level adjustment is accomplished by the auto gain control circuit (AGC) within a signal processing circuit  313  described later.  
         [0049]    A timing generator  314  generates a drive control signal for the CCD  303  based on a clock signal transmitted from a timing control circuit  202  within the camera body  2 . The timing generator  314  generates clock signals, for example, such as a storage start/end timing signal (i.e., exposure start/end), read control signal (horizontal synchronization signal, vertical synchronization signal, transfer signal and the like) of each pixel photoreception signal and the like, and outputs these signals to the CCD  303 .  
         [0050]    The signal processing circuit  313  performs specific analog signal processing of image signals (analog signals) output from the image sensing circuit  302 . The signal processing circuit  313  includes a correlation double sampling (CDS) circuit and an auto gain control (AGC) circuit, and reduces the noise of the image signals via the CDS circuit, and adjusts the level of the image signals by adjusting the gain via the AGC circuit.  
         [0051]    The light adjusting control circuit  304  controls the amount of light emitted by the built-in flash  5  during flash photography to the specific amount of light emission set by the general controller  211  of the camera body  2 . When the amount of received light attains the specific amount of emission light, a flash stop signal is output from the light adjusting control circuit  304  to the flash control circuit  214  via the general controller  211 . The flash control circuit  214  forcibly stops light emission by the built-in flash  5  in response to the emission stop signal, and in this way the amount of light emitted from the flash  5  is controlled to the specific emission amount.  
         [0052]    Within the image sensing unit  3  are provided a zoom motor  307  for moving the lens between a housed position and photography position and for changing the zoom ratio of the zoom lens  301 , and an autofocus (AF) motor  308  for focus adjustment, and a finder motor  311  for moving the lens to change the zoom ratio of the optical finder.  
         [0053]    [0053]FIG. 6 shows the internal structure of the optical finder  31 ; FIG. 6( a ) shows the telecentric state, and FIG. 6( b ) shows the wide state. The optical finder  31  is provided with a finder zoom lens comprising objective lens  310   a,  lens  310   b  and an eyepiece lens  310   c  as a finder optical system, and the magnification is changed by moving the lens  310   b  in the optical axis direction via the drive of the finder motor  311 . The magnification of the finder zoom lens  310  is limited, and in the present embodiment the obtainable magnification is between 1.0˜3.0.  
         [0054]    A warning LED  312  is provided within the optical finder  31  which warns by lighting with a specific timing described later. A photographer looking through the optical finder  31  easily becomes aware of the switch from the optical finder to the electronic finder by seeing the lighted warning LED  312 .  
         [0055]    Referring back to FIG. 5, the internal structure of the camera body  2  is described below.  
         [0056]    The general controller  211  mainly comprises a CPU, and controls each peripheral structure of the camera body  2  and the interior of the image sensing unit  3  connected by address bus, data bus, and control bus, and performs general control of photographic operations of the digital camera  1 .  
         [0057]    The flow of the image data in FIG. 5 (and FIG. 7 described later) is indicated by arrows between the peripheral structures, but actually the image data are transmitted to each peripheral structure through the general controller  211 . For this reason within the general controller  211  are provided a DRAM work RAM M 211   a,  a flash ROM  211   b  for storing control programs, previous magnification when the power is OFF and previous condition of the LCD when the power is OFF, and an expansion processor  211   c  for a thinness process and interpolation process described later.  
         [0058]    Image signal processing within the camera body  2  and structures relating to image display are described below.  
         [0059]    Analog image signals transmitted from the signal processing circuit  312  of the image sensing unit  3  are subjected to various image processing in the image processor  200  within the camera body  2 . FIG. 7 is a block diagram showing the structure of the image processor  200 . First, the analog image signal transmitted to the image processor  200  is converted to a 10-bit digital signal for each pixel in the A/D converter  205 . The A/D converter  205  converts each pixel signal (analog signal) to a 10-bit digital signal based on the clock signal of the A/D converter input from the timing control circuit  202 .  
         [0060]    The timing control circuit  202  generates a standard clock signal, and clock signals for the timing generator  314  and A/D converter  205  via control by the general controller  211 .  
         [0061]    A black level correction circuit  206  corrects the black level the A/D converted pixel signal (hereinafter referred to as “pixel data”) to a standard black level. A WB circuit  207  performs level conversion of the pixel data of each color component R, G, B, and adjusts the white balance in consideration of gamma correction in a later process. The white balance adjustment is accomplished using a level conversion table (properly speaking, the data of the table) input from the general controller  211  to the WB circuit, and the conversion coefficient (characteristics slope) of each color component of the level conversion table is set for each photographic image by the general controller  211 .  
         [0062]    A gamma correction circuit  208  corrects the gamma characteristic of the pixel data. The output from the gamma correction circuit  208  is transmitted to an image memory  209  as shown in FIG. 5.  
         [0063]    The image memory  209  is a memory for storing pixel data output from the image processor  200 , and has a 1-frame memory capacity. That is, the image memory  209  has a memory capacity sufficient to store pixel data of n×m pixels when the CCD  303  has pixels arrayed in a matrix of n lines and m columns (where n and m are natural numbers), and stores the pixel data in a corresponding memory area (address).  
         [0064]    A VRAM  210  is a buffer memory for image data reproduced and displayed on the LCD  10 . The VRAM  210  has a memory capacity sufficient to store image data corresponding to the number of pixels of the LCD  10 .  
         [0065]    According to this construction, in the photography standby state in the photographic mode, pixel data of an image sensed at specific intervals by the image sensing unit  3  are processed by the image processor  200 , and stored in the image memory  209 . The image data are subjected to a thinness process described later in accordance with the magnification set by pressing the buttons  231  and  232  (hereinafter referred to as “set magnification”), and thereafter transferred to the VRAM  210 , and displayed on the LCD  10  (live view display). In this way the photographer is able to visually confirm an object image via the image displayed on the LCD  10 .  
         [0066]    In the reproduction mode, after the image read from the memory card has been subjected to specific signal processing by the general controller  211 , the data are transmitted to the VRAM  210  and reproduced and displayed on the LCD  10 . When an image is displayed on the LCD  10 , a backlight  16  is lighted via control by the general controller  211 .  
         [0067]    Another structure within the camera body  2  is described below.  
         [0068]    A card I/F  212  is an interface for bi-directional communication with various types of memory cards installed in the card compartment  17 . Specifically, writing image data to the memory card, and reading image data from the memory card.  
         [0069]    A flash control circuit  214  is a circuit for controlling the emission of the built-in flash  5 . The flash control circuit  214  controls the emission or lack thereof, emission amount, and emission timing of the built-in flash  5  based on control signals from the general controller  211 , and controls the amount of emission of the built-in flash  5  based on an emission stop signal input from the light adjusting control circuit  304 .  
         [0070]    A clock circuit  219  manages the photograph date and time, and is driven by a separate battery not shown in the drawings.  
         [0071]    Within the camera body  2  are provided a zoom motor drive circuit  215  and AF motor drive circuit  216  for driving the zoom motor  307  and the AF motor  308 . These circuits function by the operation of an operating portion  250  of a shutter button  8  and various other types of switches and buttons described later.  
         [0072]    For example, the shutter button  8  is a two-stage switch capable of detecting the half-depression state, and full-depression state used by cameras using silver halide film (hereinafter referred to as “silver halide camera”). When the shutter button  8  is depressed half way in the photography standby state, distance information from the distance measuring sensor  306  is input to the general controller  211 . Then, the AF motor drive circuit  216  drives the AF motor  308  by instructions from the general controller  211 , so as to move the zoom lens  301  to the focus position.  
         [0073]    When buttons  231  and  232  are pressed, signals from these buttons are transmitted to the general controller  211 , and the general controller  211  specifies the set magnification obtained from the signal. The zoom motor drive circuit  215  drives the zoom motor  307  by means of the aforesaid instruction, so as to move the zoom lens and accomplish zooming. Then, the electronic zoom process described later is executed by the expansion processor  211   c.  In this way the effective magnification matches the set magnification, with the effective magnification being the actual magnification during live view or photography.  
         [0074]    Although the various structures within the camera body  2  have been described above, the general controller  211  accomplishes various other functions such as timing control and transfer of data with peripheral structures through software.  
         [0075]    For example, the general controller  211  is provided with a luminance determination function for setting an exposure control value (shutter speed), and a shutter speed setting function. The luminance determination function determines the brightness of a photographic object using the image stored in the image memory  209  and captured every {fraction (1/30)} th  second by the CCD  303  in the photography standby state. The shutter speed setting function sets the shutter speed (accumulation time of the CCD  303 ) based on the object brightness determination result of the luminance determination.  
         [0076]    The general controller  211  is provided with a filtering process function, recorded image generation function, and reproduction image generation function to accomplish the photographic image recording process.  
         [0077]    The filtering process function corrects the high frequency component of the image being recorded via a digital filter to correct image quality relating to contour.  
         [0078]    The recording image generation function reads the pixel data from the image memory  209 , and generates a thumbnail image and compressed image to be recorded on the memory card. Specifically, pixel data are read for each 8 pixels in both horizontal and vertical directions while scanning from the image memory  209  in the raster scan direction. Next, a thumbnail image is generated and transferred to the memory card and recorded on the memory card. When recording the compressed image data on the memory card, all pixel data are read from the image memory  209 , subjected a specific compression processing by a JPEG method such as Hoffman coding or two-dimensional DCT conversion, and recorded on the memory card.  
         [0079]    The specific operation is described below. When a photograph is specified by the shutter button  8  in the photography mode, a thumbnail image of the image in the image memory  209  is generated, and a compressed image compressed by a JPEG method is generated based on the set compression ratio, and both images together with tag information relating to the photographed image (information such as frame number, exposure value, shutter speed, compression ratio, date, time, flash ON/OFF data, scene information, image determination result and the like) are recorded on the memory card.  
         [0080]    The reproduction image generation function generates a reproduced image by expanding the compressed image recorded on the memory card. The specific operation is described below. When the mode setting switch  14  sets the reproduction mode, the image data of the highest frame number in the memory card are read and expanded, and transferred to the VRAM  210 . In this way the image of the highest frame number, i.e., the latest photographed image, is displayed on the LCD  10 .  
         [0081]    As shown in FIG. 5, when the memory card  91  is loaded in the card compartment  17  and processing described later is executed, the general controller  211  performs controls of the various parts described later, and normally, the control programs are installed in the flash ROM within the general controller  211 . However, other control programs and update programs for updating the control programs may be recorded on a recording medium such as the set-up memory card  92  which is loaded in the card compartment  17 , such that the control programs and update programs can be read and installed from the set-up memory card  92 .  
         [0082]    The various processes of the digital imaging device of the present invention are described below.  
         [0083]    [0083]FIG. 8 shows the condition of the electronic zoom process. In the digital camera  1  of the present embodiment, when the set magnification is greater than a specific magnification, specifically, when the set magnification is greater than the upper limit magnification (zoom ratio) 3.0x of the zoom lens  301 , the optical zoom of 3.0x of the zoom lens is used together with the electronic zoom. The electronic zoom process is described below.  
         [0084]    First, the thinness process is described which is an electronic zoom process in live view. As shown in FIG. 8, in 2x zooming, for example, a ½ thinness process is performed on image data of an area of 800×600 pixels in the center area among the 1600×1200 pixel image data within the image memory  209 , to derive image data of 400×300 pixels, which are stored in the VRAM  210 . In this way the image data of 400×300 pixels stored in the VRAM  210  are displayed on the LCD  10 .  
         [0085]    Similarly, during electronic zooming in live view, an Int(x/4) thinness process is performed on image data of region CA of Int(1600/x)xInt(1200/x) in the center area of the image data ID 1  of 1600×1200 pixels (in the present embodiment, x is a number equal to or greater than 1 but less than 2, in steps of 0.1 as one step), to derive image data ID 2  of 400×300 pixels which are stored in the VRAM  210  and displayed on the LCD  10 . Int(a) is a function representing the area of integer a.  
         [0086]    In the electronic zoom during live view, only image data of area CA corresponding to the set magnification are read in the center of the image data in the image memory  209 , culled according to the number of pixels of the LCD  10 , and displayed.  
         [0087]    The electronic zoom process during photography is described below. When photographing at 2x electronic zoom, a 2x linear interpolation process is performed on the image data of area CA of 800×600 pixels in the center area of the image data ID 1  of 1600×1200 pixels in the image memory  209 , and the data are stored in again in image memory  209  as 1600×1200 pixel image data ID 3 , and thereafter subjected to the previously mentioned compression process and the like and recorded on the memory card.  
         [0088]    Similarly, when using X-magnification electronic zooming during photography, an X-magnification linear interpolation process is performed on image data within the Int(1600/x)xInt(1200/x) in the center area of the image data of 1600×1200 pixels, and the data are again stored in image memory  209  as 1600×1200 pixel image data, then subjected to the previously mentioned compression process and the like and recorded on the memory card.  
         [0089]    In this way in electronic zooming during photography, only the image data of area CA corresponding to the set magnification are read from the center of the image data in the image memory  209 , interpolation is performed to obtain image data identical to the original number of pixels, and again stored in image memory  209 , and after the previously described processing, the data are recorded on the memory card.  
         [0090]    The thinness process and interpolation process are accomplished by the expansion processor  211   c  of the general controller  211  using the work RAM  211   a  of the general controller  211  and the image memory  209 .  
         [0091]    Processes performed from the switching ON of power to the switching OFF of power in the digital camera of the present embodiment are described below.  
         [0092]    [0092]FIG. 9 is a flow chart showing the sequence of processing after power is turned ON until power is turned OFF in the digital camera  1  of the present embodiment. The first process is the initialization process. (step S 1 ).  
         [0093]    [0093]FIG. 10 is a flow chart showing the sequence of the initialization process. In the initialization process, first, other initialization processes are executed (step S 101 ). Specifically, the work RAM  211   a,  VRAM  210 , and image memory  209  are initialized. Then, when the set magnification at the previous power OFF is greater than 3.0×, the LCD  10  is forcibly turned ON because the electronic zoom is used. Furthermore, the warning LED  312  is lighted when the electronic zoom is used in the warning LED control of the main routine. The set magnification when the power was previously turned OFF is the effective magnification at the previous power OFF.  
         [0094]    Next, the set magnification (effective magnification) at the previous power OFF recorded in the flash ROM  211   b  is read (step S 102 ). That is, in the present embodiment, the set magnification at actuation is identical to the set magnification at the previous power OFF, and for this reason the set magnification at the previous power OFF recorded in the flash ROM  211   b  when the camera was last used (i.e., the process of step S 7  described later) is read out from memory.  
         [0095]    Then, a determination is made as to whether or not the set magnification of the previous power OFF is greater than 3.0x (step S 103 ), and if the set magnification is greater than 3.0×, the routine advances to step S 104 , whereas when the set magnification is not greater than 3.0×, the routine advances to step S 108 .  
         [0096]    The following process is executed when the set magnification at the previous power OFF is greater than 3,0×.  
         [0097]    First, the read set magnification of the previous power OFF is set, and electronic zooming is executed in accordance with the set magnification (step S 104 ). That is, electronic zooming is performed at a magnification of the set magnification divided by 3.0.  
         [0098]    Then the zoom lens  301  is moved to the 3.0x position by the drive of the zoom motor  307  (step S 105 ). That is, the effective magnification of both the optical zoom and electronic zoom are set to equal the set magnification (greater than 3.0×).  
         [0099]    Then, the finder zoom lens  310  is moved to the 3.0x position by the drive of the finder motor  311  (step S 106 ). Then, the LCD  10  is turned ON (step S 107 ). In this way the LCD  10  displays image data subjected to the previously described thinness process. The process ends when the set magnification greater than 3.0x has been set.  
         [0100]    The process when the set magnification of the previous power OFF is less than 3.0×is determined in step S 103  is described below.  
         [0101]    First, the zoom lens  301  is moved to the position corresponding to the set magnification by the drive of the zoom motor  307  (step S 108 ). Then, the finder zoom lens  310  is moved to the position corresponding to the set magnification by the drive of the finder motor  311  (step S 109 ). The effective magnification is then equal to the set magnification.  
         [0102]    Next, the ON/OFF state of the LCD  10  recorded in the flash ROM  211   b  at the previous power OFF is read (step S 110 ).  
         [0103]    Then, a determination is made as to whether or not the LCD  10  was OFF at the previous power OFF (step S 112 ). When the LCD  10  was ON, the routine advances to step S 107 , and the LCD  10  is turned ON. Conversely, when the LCD  10  was OFF, the initialization process ends.  
         [0104]    Referring to FIG. 9, the zoom process for photography standby (live view) is executed (step S 2 ). In step S 2 , when the button  231  is pressed, the zoom magnification is decreased one step, and when the button  232  is pressed, the zoom magnification is increased one step. Electronic zoom is used when the set magnification is greater than 3.0×.  
         [0105]    The zoom process during photography standby is described below. FIG. 11 is a flow chart showing the sequence of the zoom process during photography standby.  
         [0106]    First, a determination is made as to whether or not button  232  has been pressed (step S 201 ); if the button  232  has been pressed, the routine advances to step S 202 , whereas if the button  232  has not been pressed, the routine advances to step S 208 .  
         [0107]    The process when button  232  has been pressed is described below. First, a determination is made as to whether or not the current set magnification is 6.0x (step S 202 ). If the set magnification is 6.0×, the zoom process for photography standby ends because the effective magnification cannot be increased. When the current set magnification is not 6.0×, the routine advances to step S 203 .  
         [0108]    When the set magnification is not 6.0×, the set magnification is increased one step (step S 203 ).  
         [0109]    Then, a determination is made as to whether or not the set magnification is greater than 3.0x (step S 204 ). If the set magnification is greater than 3.0×, the routine advances to step S 205 , whereas when the set magnification is not greater than 3.0×, the routine advances to step S 207 .  
         [0110]    When the set magnification is greater than 3.0×, the original image is subjected to thinness process based on the set magnification (step S 205 ).  
         [0111]    Then, the LCD automatic display process is executed (step S 206 ).  
         [0112]    For example, when the set magnification is 2.8x and the button  232  is pressed once, the optical zoom is increased to 2.9×, and when pressed once more, the optical zoom is increased to 3.0×. Since the limit of the optical zoom is exceeded when the button  232  is pressed once more, both 3.0x optical zoom and electronic zoom controls are executed. If the LCD  10  display is OFF at this time, the LCD  10  is turned ON in addition to the warning. This process is the LCD automatic display control process. Details of the process sequence are described below.  
         [0113]    [0113]FIG. 12 is a flow chart showing the process of the LCD automatic display control. In the LCD automatic display control process, it is necessary to start the LCD display with a set magnification of 3.1×, and, therefore a determination is made as to whether or not the set magnification is 3.1x (step S 2061 ). When the set magnification is not 3.1×, the LCD automatic display control process ends, whereas when the set magnification is 3.1×, the routine advances to step S 2062 .  
         [0114]    When the set magnification is 3.1×, a determination is made as to whether or not the LCD  10  is turned OFF (step S 2062 ). If the LCD  10  is ON, the LCD automatic display control process ends, whereas when the LCD  10  is OFF, the routine advances to step S 2063 , and the LCD  10  is turned ON for display (step S 2063 ).  
         [0115]    The LCD automatic display control process ends, and the process ends when the set magnification is determined to be greater than 3.0x in the determination of step S 204  of FIG. 11.  
         [0116]    Conversely, when the determination of step S 204  is that the set magnification is equal to or less than 3.0×, the zoom motor  307  is driven one step to move the zoom lens  301  to the telecentric side (step S 207 ), and the process of the photography standby ends.  
         [0117]    The process when the determination of step S 204  is that the button  232  has not been pressed is described below.  
         [0118]    First, a determination is made as to whether or not the button  231  has been pressed (step S 208 ). If the button  231  has not been pressed, there is not change to the set magnification, and the process of photography standby ends, whereas when button  231  has been pressed, the routine advances to step S 209 .  
         [0119]    When the button  231  has been pressed, a determination is made as to whether or not the current set magnification is 1.0x (step S 209 ). When the current set magnification is 1.0×, the process of photography standby ends because a lesser magnification is impossible. When the current magnification is not 1.0×, the routine advances to step S 210 .  
         [0120]    When the current set magnification is not 1.0×, the set magnification is decreased 1 step (step S 210 ).  
         [0121]    Then, a determination is made as to whether or not the set magnification is greater than 3.0x (step S 211 ). When the set magnification is greater than 3.0×, the routine advances to step S 212 , whereas when the set magnification is not greater than 3.0×, the routine advances to step S 231 .  
         [0122]    When the set magnification is greater than 3.0×, the original image is subjected to the thinness process based on the set magnification (step S 212 ).  
         [0123]    Conversely, when the set magnification is equal to or less than 3.0×, the zoom motor  307  is driven one step to move the zoom lens  301  to the wide side (step S 213 ), and the process of photography standby ends.  
         [0124]    Referring to FIG. 9, next, the LCD ON/OFF control process is executed (step S 3 ). When the set magnification is 3.1x or greater, the LCD display is not always in the ON state, and a user may optionally set the LCD display to OFF. Regardless of the magnification, the LCD  10  ON/OFF state is switched each time the LCD button  321  is pressed. For this reason the LCD can be positively turned OFF to prevent battery consumption while being aware of the use of the electronic zoom.  
         [0125]    The sequence of the LCD ON/OFF control process is described below. FIG. 13 is a flow chart showing the sequence of the LCD ON/OFF control process.  
         [0126]    First, a determination is made as to whether or not the LCD button  321  has been pressed (step S 301 ). If the LCD button  321  has not been pressed, the LCD ON/OFF control process ends, whereas when button  321  has been pressed, the routine advances to step S 302 .  
         [0127]    When the LCD button  321  has been pressed, a determination is made as to whether or not the LCD  10  is turned OFF (step S 302 ). If the LCD  10  is OFF, the routine advances to step S 303 , and the LCD  10  is turned ON for display (step S 303 ). Conversely, if the LCD  10  is ON, the LCD  10  is turned OFF (step S 304 ), and the LCD ON/OFF control process ends.  
         [0128]    As can be understood from the zoom process during photography standby of FIG. 11 and the LCD ON/OFF control process described above, the LCD display ON/OFF state does not change even when the button  231  is pressed, and conversely changing from the telecentric side to the wide side, and the magnification is reduced sequentially step-by-step from 6.0x and from 3.1x to 3.0×. This arrangement is due to the strong unease when the LCD is suddenly turned OFF and mistaken belief of a power outage when framing a photo with the LCD  10  , which adversely affects operability. In the digital camera  1  of the present embodiment, such events are prevented.  
         [0129]    Referring to FIG. 9, the warning LED control process is then executed (step S 4 ). During electronic zoom, since the confirmable range by the optical finder does not match the actual photographic range, the warning LED  312  is always lighted when the set magnification is 3.1 or greater. The power consumption of the LED is not a problem even when always lighted because the power consumption is very slight compared to the LCD  10 .  
         [0130]    Details of the process sequence of the warning LED control process are described below. FIG. 14 is a flow chart showing the sequence of the warning LED control process.  
         [0131]    First, a determination is made as to whether or not the set magnification is 3.1x or greater (step S 401 ). If the set magnification is 3.1x or greater, the routine advances to S 402 , whereas when the set magnification is not 3.1x or greater, the routine advances to step S 404 .  
         [0132]    When the set magnification is 3.1 or greater, a determination is made as to whether or not the warning LED  312  is OFF (step S 402 ). If the warning LED  312  is ON, the warning LED control process ends, whereas when the warning LED  312  is OFF, it is turned ON (step S 403 ), and the warning LED control process ends.  
         [0133]    Similarly, even when the set magnification is less than 3.1×, a determination is made as to whether or not the warning LED  312  is OFF (step S 404 ). If the warning LED  312  is OFF, the warning LED control process ends, whereas when the warning LED  312  is ON, the warning LED  312  is turned OFF (step S 405 ), and the warning LED control process ends.  
         [0134]    Referring to FIG. 9, then other processes are executed (step S 5 ). This process is the basic process of the digital camera, and is a process of the photographic mode in which the auto exposure (AE) and autofocus (AF) are performed are by half pressing the shutter button  8 . When the shutter button  8  is fully pressed, if necessary flash emission is performed, and image data (i.e., data subjected to the electronic zoom interpolation process) are compressed and recorded on the memory card. The process in the photographic mode is also executed in step S 5 .  
         [0135]    Next, a determination is made as to whether or not the power switch  227  has been pressed (step S 6 ). If the power switch has not been pressed, the routine returns to step S 2 , and until the power switch  227  has been pressed, the processes of steps S 2 -S 5  are repeated. Then, when the power switch  227  is pressed, the routine advances to step S 7 .  
         [0136]    When the power switch S 7  is pressed, the current set magnification (effective magnification) is written to the flash ROM  211   b,  and the state of the LCD  10  display (ON/OFF) is written to the flash ROM  211   b  for use at subsequent start (step S 7 ).  
         [0137]    Finally, the power OFF process to turn OFF the power supply is executed (step S 8 ).  
         [0138]    This ends the description of the processes performed in the digital camera of the present embodiment.  
         [0139]    According to the present embodiment as described above, during electronic zooming by pixel thinness or pixel interpolation by an expansion processor  211   c  used as an electronic zoom means, the LCD  10  is forcibly turned ON as an electronic finder regardless of the previous state. Therefore, since the LCD  10  has a zoom function corresponding to the effective magnification including the electronic zoom by the processing by the expansion processor  211   c,  the image of the photographic object corresponding to the effective sensing magnification during electronic zooming can be confirmed on the LCD  10  even when the optical finder  31  does not possess this zoom function. Accordingly, The compactness of the digital camera is not hindered, the photographic object is easily confirmed, and framing is simple. Furthermore, The electrical power of the digital camera can be conserved by switching OFF the LCD  10  when electronic zoom is not used.  
         [0140]    Since the warning LED  312  is lighted and the LCD  10  is turned ON when using the electronic zoom, the photographer is easily aware when electronic zoom is used.  
         [0141]    Furthermore, when the effective magnification of the joint operation of the zoom lens  301  as an optical zoom means and the expansion processor  211   c  as an electronic zoom means is outside the magnification range obtainable by the optical finder  31  (specifically, when the effective magnification is greater than 3.0×), the warning LED  31  is lighted and the image is displayed on the LCD  10 , such that the mismatch of the photographic range and the field of view of the optical finder  31  can be shown when using the optical finder  31 .  
         [0142]    Similarly, when the effective magnification of the joint operation of the zoom lens  301  and the expansion processor  211   c  is outside the magnification range obtainable by the optical finder  31  (specifically, when the effective magnification is greater than 3.0×), the LCD  10  is forcibly turned ON regardless of its previous state. In this way the mismatch of the photographic range and the field of view of the optical finder  31  can be shown by referencing the LCD  10  when using the optical finder  31 .  
         [0143]    Since the LCD  10  is forcibly turned ON when the starting magnification exceeds the range obtainable by the optical finder  31  when the digital camera is started, i.e., when the effective magnification is determined to be greater than 3.0×, the photographer can be alerted to the mismatch between the photographic range and the field of view of the optical finder  31  when the starting magnification exceeds the magnification obtainable by the optical finder  31 .  
         [0144]    Since the power OFF magnification of the previous power shutdown recorded in flash ROM  211   b  is set as the starting magnification, the photographer need not set the magnification of the previous power OFF because the starting magnification used is the magnification of the previous power OFF, thereby improving operability.  
         [0145]    Since an operation switch is provided which is capable of turning OFF the LCD  10  when the LCD  10  is in the forced ON state, battery power consumption can be greatly conserved by turning OFF the power-draining LCD  10  with the full awareness of the mismatch of the photographic range and the field of view of the optical finder  31 .  
         [0146]    Since the photographer is warned by the lighting of the LED  312  and display on the LCD  10  when the starting magnification exceeds the magnification range obtainable by the optical finder  31 , the photographer is alerted to the mismatch of the photographic range and the field of view of the optical finder  31 .  
         [0147]    Modifications  
         [0148]    Although the digital camera and recording medium of the embodiments have been described by way of examples, the present invention is not limited to these examples.  
         [0149]    For example, although the warning LED  312  is lighted and displayed in the warning LED control process, the warning means may be suitably modified. For example, a speaker may be provided to issue an audible warning or warning sound. FIG. 15 shows a modification of the warning means. This warning means is provided with a Porro prism  401  within the optical system of the optical finder, a transmission type LCD  402  disposed above the Porro prism  401 , and a transparent window  403  provided on the top surface of the image sensing unit  3  is disposed above the LCD  402 . External light entering the window  403  is transmitted through the transmission type LCD  402 , and arrives at the photographer side via the Porro prism  401 . Then, when the electronic zoom is used, a warning text is displayed on the transmission type LCD  402  and alerts the photographer. In this way the photographer can confirm the warning text overlaid on the photographic object via the optical finder, thereby easily being made aware of the use of the electronic finder.  
         [0150]    The position at which the warning means is provided is also optional. Specifically, the warning means may be disposed on the surface of the camera body  2  insofar as it is observable while looking in the optical finder.  
         [0151]    In the above described embodiments, the electronic finder is turned ON when transitioning from a state of using the optical zoom alone to the state of using the optical zoom and electronic zoom in combination. However, the present invention is not limited to this arrangement, and the range of the art of the present invention further includes which zoom only using an electronic zoom wherein the electronic zoom is turned ON when transition from a state of no zoom to a state of using the electronic zoom.  
         [0152]    In the above embodiments, when the set magnification (effective magnification) exceeds the upper limit magnification (3.0×) of the optical finder, the warning LED  312  is lighted, and the LCD  10  forcibly displays in warning. However, the present invention is not limited to this arrangement, inasmuch as the warning LED  312  may be lighted and LCD  10  forced to display in warning when a specific lower limit different from 1.0x of the optical finder is set.  
         [0153]    Although the upper limit magnification (zoom ratio) of the zoom lens  301  used as an optical zoom and the upper limit magnification (zoom ratio) of the optical finder  31  are both 3.0x in the above embodiments, these upper limits need not necessarily be identical. In this case, when, for example, the optical zoom magnification exceeds the zoom ratio of the optical finder, the warning LED  312  may be lighted and the display of the LCD  10  may be forced as an electronic finder.  
         [0154]    Although the optical zoom is used in electronic zooming in the above embodiments, a mode may be provided for using electronic zoom alone. In this case, when the electronic zoom magnification exceeds the zoom ratio of the optical finder, the LCD  10  display may be forced as an electronic finder. Furthermore, while the above embodiments have been described as performing a pixel thinness process or pixel interpolation process after trimming the center area when using the electronic zoom, trimming may be performed alone.  
         [0155]    Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modification will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.