Abstract:
An image capturing apparatus having an optical zooming lens which varies shooting magnification, an imaging sensor which captures image data of a subject image focused through the optical zooming lens, a zooming ring movable around a lens barrel containing the optical zooming lens for varying a focal length of the optical zooming lens, and a digital zooming portion which digitally enlarges the image data by reading a portion of the image data from the image data captured by the imaging sensor. In the above image capturing apparatus, the digital zooming portion is operated in response to a detection that the zooming ring reaches a predetermined position when a digital zooming instruction is input to the image capturing apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based on Japanese Patent Application No.2004-341987 filed in Japan on Nov. 26, 2004, the entire content of which is hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an image capturing apparatus having optical zooming and digital zooming capabilities.  
         [0004]     2. Description of the Related Art  
         [0005]     In recent years, digital cameras which photograph subjects by capturing subject images as digital data by means of an imaging device such as a CCD or a CMOS have been spreading rapidly, replacing the traditional silver halide cameras which photograph subjects by exposing subject images onto silver halide film.  
         [0006]     Digital cameras are known that have two different zooming functions, an optical zooming function which optically varies shooting magnification by moving an optical zooming lens relative to the camera body and thereby varying its focal length, and a digital zooming function which digitally enlarges a portion of an image by reading the portion of the image from the subject image captured by the imaging device. In this type of digital camera, since the digital zooming has the shortcoming that the image quality degrades due to reduced pixel resolution, it is usual practice to use the optical zooming in the magnification range that can be covered by the optical zooming, and to activate the digital zooming if a larger magnification is desired.  
         [0007]      FIG. 1 ( a ) shows a side view of a single-reflex digital camera  100  according to the prior art, and  FIG. 1 ( b ) shows a rear view of the single-reflex digital camera  100  in  FIG. 1 ( a ). The digital camera  100  comprises a camera body  112  as a camera casing, and a lens barrel  114  which contains an optical zooming lens. A built-in flash  116  which, when activated, automatically pops up to the position indicated by dotted lines is mounted on the top panel of the camera body  112 . An annular zooming ring  118  is fitted around the lens barrel  114 . When the zooming ring  118  is manually rotated, the optical zooming lens moves forward or backward inside the lens barrel  114  relative to the camera body  112  along the optical axis of the lens, thereby varying the optical zooming magnification.  
         [0008]     On the rear panel of the digital camera  100  are mounted a viewfinder  120  through which the subject is viewed, a rear monitor  122  constructed, for example, from a liquid crystal display for displaying the subject image in live view mode or for presenting captured images for viewing, a four-way key pad  124  and a set button  126  used when making various settings from the menu displayed on the rear monitor  122 , and a digital zooming button  128  for varying the digital zooming magnification.  
         [0009]     In this digital camera  100 , the optical zooming is adjusted between the wide angle end and the telephoto end by rotating the zooming ring  114  and, when an additional zooming is desired, the digital zooming is activated by operating the digital zooming button  128 .  
         [0010]     However, in the digital camera  100  described above, since separate members have to be operated to activate the optical zooming and the digital zooming, respectively, not only is the operation difficult to understand and cumbersome, but there is the possibility of erroneous operation.  
       SUMMARY OF THE INVENTION  
       [0011]     A primary object of the present invention is to provide an image capturing apparatus which has optical zooming and digital zooming capabilities, and which ensures extremely simple and user friendly operation while eliminating the possibility of erroneous operation.  
         [0012]     The above object of the present invention is achieved by providing an image capturing apparatus comprising an optical zooming lens which moves in forward and backward directions relative to a body of the image capturing apparatus so as to vary shooting magnification, an imaging sensor which captures image data of a subject image focused through the optical zooming lens, a zooming ring movable around a lens barrel containing the optical zooming lens, and which varies a focal length of the optical zooming lens, a digital zooming portion which digitally enlarges the image data by reading a portion of the image data from the image data captured by the imaging sensor, a digital zooming instruction member which inputs a command to operate the digital zooming portion, a detecting portion which detects a position of the zooming ring, and a controller which controls the digital zooming portion to operate in response to a detection that the zooming ring reaches a predetermined position when the digital zooming instruction member inputs the command to operate the digital zooming portion.  
         [0013]     These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings, which illustrate specific embodiments of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings in which:  
         [0015]      FIG. 1 ( a ) is a side view of a single-reflex digital camera according to the prior art;  
         [0016]      FIG. 1 ( b ) is a rear view of the prior art digital camera;  
         [0017]      FIG. 2  is a front view of a single-reflex digital camera according to one embodiment of the present invention;  
         [0018]      FIG. 3  is a side view of the digital camera of  FIG. 2 ;  
         [0019]      FIG. 4  is a rear-view of the digital camera of  FIG. 2 ;  
         [0020]      FIG. 5  is a schematic block diagram showing the internal configuration of the digital camera of  FIG. 2 ;  
         [0021]      FIG. 6  is a perspective view showing a cam ring with a cam groove formed therein and a pin which is synchronized with the operation of a digital zooming switch;  
         [0022]      FIG. 7  is a diagram showing a perspective view of the cam ring containing a detecting portion for detecting the rotation angle of the cam ring, and also showing the waveforms of signals output from photo reflectors constituting the detecting portion;  
         [0023]      FIG. 8 ( a ) and  FIG. 8 ( b ) are diagrams for explaining a method of how the direction in which a zooming ring is operated is judged by detecting a change occurring in the state of the signal output from either one of the photo reflectors;  
         [0024]      FIG. 9 ( a ) is a diagram showing the condition of a main mirror in an optical viewfinder mode;  
         [0025]      FIG. 9 ( b ) is a diagram showing the condition of the main mirror in a live view display mode using a rear monitor;  
         [0026]      FIGS. 10   a ,  10   b  and  10   c  are diagrams respectively showing a screen displayed on the rear monitor for digital zooming mode setting;  
         [0027]      FIG. 11  is a graph showing the relationship between the rotation angle of the zooming ring and focal length in a linear mode;  
         [0028]      FIG. 12  is a graph showing the relationship between the rotation angle of the zooming ring and focal length in a full range mode; and  
         [0029]      FIG. 13  is a flow chart for explaining the operation of the digital camera of  FIG. 2 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]     Embodiments of an image capturing apparatus according to the present invention will be described below with reference to the accompanying drawings.  
         [0031]      FIG. 2  is a front view of a single-reflex digital camera  10  according to one embodiment of the present invention,  FIG. 3  is a side view of the digital camera  10 , and  FIG. 3  is a rear view of the digital camera  10 .  
         [0032]     As shown in  FIG. 2 , the digital camera  10  comprises a camera body  12  as a camera casing, and a cylindrically shaped lens barrel  14  which contains an optical zooming lens. A built-in flash  16  which, when activated, automatically pops up to the position indicated by dotted lines is mounted on the top panel of the camera body  12 . An annular zooming ring  18  is fitted around the lens barrel  14 . When the zooming ring  18  is manually rotated, the optical zooming lens moves forward or backward inside the lens barrel  14  relative to the camera body  12 , the focal length thus being changed to vary the optical zooming magnification.  
         [0033]     One end of the camera body  12  is formed as a grip  20  which is gripped by hand, and a shutter release button  22  is mounted on the top of the grip  20 . A mode setting dial  24  for setting modes such as various still image shooting modes, moving image shooting mode, etc. is mounted on the top panel of the camera body  12 . Further, a digital zooming switch  26 , which is slid backward in the axial direction of the lens barrel  14  (i.e., in the leftward direction in  FIG. 3 ) and is thus turned on to enable the digital zooming for operation, is mounted on an outer circumferential portion of the lens barrel  14 .  
         [0034]     The digital zooming switch  26  is not limited to a slide switch type, but other suitable type of switch (for example, a pushbutton type switch or a rotary type switch) may be employed.  
         [0035]     As shown in  FIG. 4 , on the rear panel of the camera body  12  are mounted a slide-type main switch  28  for turning on and off the power of the digital camera  10 , a viewfinder  30  through which the subject is viewed, a rear monitor  32  constructed, for example, from a liquid crystal display for displaying the subject image in live view mode or for presenting captured images for viewing, a four-way key pad  34  and an enter button  36  used when making various settings from the menu displayed on the rear monitor  32 , and a camera shake correction button  38  for activating and deactivating a camera shake correction function.  
         [0036]      FIG. 5  is a schematic block diagram showing the internal configuration of the digital camera  10 .  
         [0037]     An optical image of the subject, introduced through the objective lens and the zooming lens in the lens barrel  14 , is focused on a CCD (Charge Coupled Device)  40  which is one example of an imaging device. The CCD  40  converts the thus focused optical image of the subject into electrical image signals (signals comprising a series of pixel signals proportional to the light received at individual pixels) representing R (red), G (green), and B (blue) color components, and outputs the electrical image signals to a controller  42 . A timing control circuit  44  generates a drive control signal for the CCD  40  in response to a command signal issued from the controller  42 .  
         [0038]     A lens driver  46  controls the driving of a lens group and a diaphragm member contained in the lens barrel  14 , and comprises an aperture control circuit which controls the aperture of the diaphragm member, a zooming control circuit which varies zooming magnification by driving a motor, and a focus control circuit which performs focus control by driving a motor.  
         [0039]     When the digital zooming switch  26  is set ON, an ON signal is output to the controller  42 .  
         [0040]     A flash circuit  48  controls the intensity of light that the built-in flash  16  produces for flash shooting to the prescribed flash intensity set by the controller  42 .  
         [0041]     A microphone  50  is used to gather sound during moving image shooting.  
         [0042]     An operation portion  52  includes operating members such as the shutter release button  22 , the mode setting dial  24 , the main switch  28 , the four-way key pad  34 , the enter button  36 , the camera shake correction button  38 , etc., and information concerning the operation of any of these operating members is sent to the controller  42 .  
         [0043]     A speaker  54  is used to reproduce sound when playing back recorded moving images for viewing.  
         [0044]     The liquid crystal display LCD is the rear monitor  32 , and is used to present a live view display of the subject image captured by the CCD  40 , reproduce recorded images for viewing, or display a menu screen or a mode setting screen when making various settings.  
         [0045]     The controller  42  comprises, for example, a CPU, and is responsible for the overall control of image shooting and playback functions. The controller  42  includes a digital zooming portion which digitally enlarges an image by reading a portion of the image from the subject image captured by the CCD  40 . The digital zooming portion is enabled for operation when the digital zooming switch  26  is set ON. A memory card  62  is connected to the controller  42  via a card interface  60 . Further, the controller  42  is capable of communicating with an external device (for example, a personal computer) via a communication interface  64 .  
         [0046]     The lens barrel  14  is equipped with a detecting portion  66  as will be described later, and signals from the detecting portion  66  are input to the controller  42 .  
         [0047]     As shown in  FIG. 6 , the lens barrel  14  contains a cylindrically shaped cam ring  70  which is mounted concentric with the center of the barrel. The cam ring  70  is constructed to rotate in arrow direction A with the rotation of the zooming ring  18  fitted around the outer circumference of the lens barrel  14 .  
         [0048]     A cam groove  72  is formed in an outer circumferential portion of the cam ring  70 . The cam groove  72  comprises a slanted groove portion  72   a , which is slanted, for example, at 45 degrees relative to the circumferential direction of the cam ring  70  or the lens barrel  14 , and a circumferentially extending groove portion  72   b , which extends along the circumferential direction.  
         [0049]     One or more optical zooming lenses are housed in the cam ring  70 , and a cam follower pin  74  fixed to a lens frame member holding the optical zooming lens(es) is engaged in the cam groove  72 . Accordingly, when the cam ring  70  is rotated by operating the zooming ring  18 , the cam follower pin  74  moves along the slanted groove portion  72   a  of the cam groove  72 , causing the lens frame member holding the optical zooming lens(es) to move along the optical axis thereof, and hence the optical zooming lens(es) to move forward or backward relative to the camera body  12 , thereby varying the optical zooming magnification.  
         [0050]     Here, when the cam follower pin  74  is located at one end  75  of the slanted groove portion  72   a , the optical zooming lens(es) is at the wide angle end, the position closest to the camera body  12 ; on the other hand, when the cam follower pin  74  is located at the other end  76  of the slanted groove portion  72   a , the optical zooming lens(es) is at the telephoto end, the position farthest from the camera body  12 .  
         [0051]     As shown in  FIG. 6 , a pin  27  as a restricting member is connected to the digital zooming switch  26  mounted on an outer circumferential portion of the lens barrel  14 . When the digital zooming switch  26  is slid into the OFF position, the pin  27  engages in the cam groove  27  at or near the position where the slanted groove portion  72   a  and the circumferentially extending groove portion  72   b  of the cam groove  72  meet; on the other hand, when the digital zooming switch  26  is slid into the ON position, the pin  27  disengages from the cam-groove  72 .  
         [0052]     Accordingly, when the digital zooming switch  26  is OFF, since the cam follower pin  74  strikes the pin  27  at the telephoto end position of the optical zooming, the zooming ring  18  and the cam ring  70  are prevented from being further rotated beyond that position.  
         [0053]     On the other hand, when the digital zooming switch  26  is ON, since the pin  27  is disengaged from the cam groove  72 , the cam follower pin  74  is allowed to move along the cam groove  72  from the slanted groove portion  72   a  into the circumferentially extending groove portion  72   b , thus allowing the zooming ring  18  and the cam ring  70  to be further rotated beyond the telephoto end position of the optical zooming.  
         [0054]     Here, if the zooming ring  18  is further rotated beyond the telephoto end position of the optical zooming, since the cam follower pin  74  just moves along the circumferentially extending groove portion  72   b  of the cam groove  72 , the optical zooming lens stays at the telephoto end position, and the optical zooming is thus maintained at its maximum magnification. Subsequently, when the zooming ring  18  is rotated so as to move the cam follower  74  into the circumferentially extending groove portion  72   b  of the cam groove  72 , since the digital zooming switch  26  is in the ON position and the digital zooming is thus enabled for operation, the digital zooming is activated by detecting that the zooming ring  18  has been further rotated beyond the telephoto end position of the optical zooming.  
         [0055]     Further, as shown in  FIG. 7 ( a ), two band-like patterns  77  and  80  extending in parallel in the circumferential direction are formed on the outer circumferential surface of the cam ring  70 . The major portions of the band-like patterns  77  and  80  are formed, for example, as white patterns  78  and  81  having high optical reflectivity, but the portions lying within a certain angular range are formed, for example, as black-and-white patterns  79  and  82  each having high reflectivity sections alternating with low reflectivity sections. Photo reflectors PR 1  and PR 2  for projecting light and detecting reflected light are mounted in the lens barrel  14  at positions opposite the respective band patterns  77  and  80 .  
         [0056]     The band patterns  77  and  80  and the photo reflectors PR 1  and PR 2  together constitute the detecting portion  66 .  
         [0057]     In the band patterns  77  and  80 , the portions lying within a first angular range X correspond to the optical zooming region defined by the white patterns  78  and  81 ; within this range, the photo reflectors PR 1  and PR 2  do not output any signals to the controller  42 . As a result, the controller  42  can determine that the moving range of the zooming ring  18  in this case is in the optical zooming region (that is, the range within which the cam follower pin  74  moves along the slanted groove portion  72   a  of the cam groove  72 ).  
         [0058]     On the other hand, the portions lying within a second angular range Y correspond to the digital zooming region defined by the black-and-white patterns  79  and  82 ; within this range, the photo reflectors PR 1  and PR 2  respectively output rectangular pulse signals  83  and  85  to the controller  42 . As a result, the controller  42  can determine that the moving range of the zooming ring  18  in this case is in the digital zooming region (that is, the range within which the cam follower pin  74  moves along the circumferentially extending groove portion  72   b  of the cam groove  72 ), and can also detect the amount of rotation of the zooming ring  18  from the number of occurrences of the respective rectangular pulse signals  83  and  85 .  
         [0059]     In this case, since the pattern positions of the black-and-white patterns  79  and  82  are displaced from each other in the circumferential direction, the timing of the rectangular pulse signal  83  output from the photo reflector PR 1  is somewhat displaced from the timing of the rectangular pulse signal  85  output from the photo reflector PR 2 . To describe more specifically, in the initial state, there are only four kinds of patterns A, B, C, and D, as shown in FIGS.  8 ( a ) and ( b ). That is, the pattern A in which the signals from the photo reflectors PR 1  and PR 2  are both low (L), the pattern B in which the signal from the photo reflector PR 1  is high (H) while the signal from the photo reflector PR 2  is low (L), the pattern C in which the signals from the photo reflectors PR 1  and PR 2  are both high (H), and the pattern D in which the signal from the photo reflector PR 1  is low (L) while the signal from the photo reflector PR 2  is high (H). When the zooming ring  18  is rotated forward or backward from the initial state of any one of the four kinds of patterns, the signal state of either one of the photo reflectors changes earlier than the signal state of the other. It can thus be determined whether the zooming ring  18  has been rotated forward or backward, by checking which photo reflector has changed signal state earlier than the other.  
         [0060]     Here, the detecting portion  66  for detecting the amount of rotation of the zooming ring  18  when the rotating range of the zooming ring  18  is in the digital zooming region is not limited to the above-described configuration, but may be constructed using, for example, an encoder for reading electrical ON/OFF patterns and an electrical contact.  
         [0061]     When the digital camera  10  is used in the optical zooming region, the user can view the subject image through the viewfinder  30 . That is, as shown in  FIG. 9 ( a ), the subject image introduced through the lens group in the lens barrel  14  into the camera body  12  is first reflected upward by a main mirror  84  and then reflected twice in a pentaprism  86  for introduction into the viewfinder  30 . At this time, the CCD  40  is covered by a closed shutter  88 .  
         [0062]     On the other hand, when the digital camera  10  is used in the digital zooming region, the user can view the subject image in the live view mode on the rear monitor  32 . That is, in the live view mode, since the main mirror  84  is flipped up in arrow direction B and the shutter  88  is opened, as shown in  FIG. 8 ( b ), the subject image introduced through the lens group in the lens barrel  14  into the camera body  12  is captured by the CCD  40 , and the image captured by the CCD  40  is displayed on the rear monitor  32  under control of the controller  42 .  
         [0063]     Here, when the digital camera  10  is used in the optical zooming region, if the shutter release button  22  on the top of the camera body  12  is pressed, the main mirror  84  is flipped up and the shutter  88  is opened as shown in FIG.  9 ( b ), and the subject image is thus captured by the CCD  40 .  
         [0064]     In the digital camera  10  of the present invention, either a linear mode or a full range mode can be selected for the digital zooming. First, the menu screen is displayed on the rear monitor  32 , as shown in  FIGS. 10   a  and  10   b , and “Custom 1” is selected from the menu screen by operating the four-way key pad  34  and the enter button  36 ; then, either the linear mode or the full range mode is selected from the “Custom 1” screen by operating the four-way key pad  34  and the enter button  36 .  
         [0065]     The selected mode is displayed at the bottom of the rear monitor  32 .  
         [0066]     The linear mode here refers to the mode in which the rate of change of the digital zooming magnification with respect to the rotation angle (i.e., the amount of rotation) of the zooming ring  18  is set equal to the rate of change of the optical zooming magnification to provide, for example, a maximum digital zooming magnification of 1.33 times as shown in  FIG. 11 , when it is assumed that the rotation angle range from 0 to 80 degrees relative to the initial position of the zooming ring  18  is the optical zooming region and the range from 80 to 120 degrees is the digital zooming region.  
         [0067]     By contrast, the full range mode refers to the mode in which the rate of change of the digital zooming magnification with respect to the rotation angle (i.e., the amount of rotation) of the zooming ring  18  is set larger than the rate of change of the optical zooming magnification to provide, for example, a maximum digital zooming magnification of 3 times as shown in  FIG. 12 , when it is assumed that the rotation angle range from 0 to 80 degrees relative to the initial position of the zooming ring  18  is the optical zooming region and the range from 80 to 120 degrees is the digital zooming region. In the full range mode, there are cases where the rate of change of the digital zooming magnification is smaller than the rate of change of the optical zooming magnification, depending on the relationship between the optical zooming magnification and the digital zooming magnification.  
         [0068]     Next, the operation of the digital camera  10  having the above configuration will be described with reference to the flow chart of  FIG. 13 . The flow chart here deals with the digital camera  10  of the type in which the lens barrel  14  is interchangeable on the camera body  12 .  
         [0069]     When the interchangeable lens barrel  14  is attached to the camera body  12  (step S 1 ), and the camera is powered on by operating the main switch  28  (step S 2 ), the controller  42  in the camera body  12  communicates with the ROM built in the lens barrel  14  to acquire information stored in the ROM, such as information concerning the focal length and information concerning the rate of change of the optical zooming magnification with respect to the amount of rotation of the zooming lens  18  (step S 3 ).  
         [0070]     Then, when the digital zooming switch  26  is set ON, and either the linear mode or the full range mode is selected as the digital zooming mode by user operation (step S 4 ), the controller  42  calculates the rate of change of the digital zooming magnification that matches the selected mode (step S 5 ).  
         [0071]     When the digital zooming switch  26  is set ON, the digital zooming portion of the controller  42  is enabled for operation, and the pin  27  connected to the digital zooming switch  26  is disengaged from the cam groove  72  of the cam ring  70  in synchronization with the ON operation, thus allowing the zooming ring  18  to be further rotated beyond the telephoto end position of the optical zooming. As a result, when the zooming ring  18  is rotated beyond the telephoto end position of the optical zooming, the digital zooming is activated.  
         [0072]     Thereafter, the controller  42  determines whether the zooming ring  18  has been rotated for operation (step S 6 ). Whether the zooming ring  18  has been operated or not can be detected by detecting the change in the focal length of the image capturing lens when the zooming ring  18  is in the optical zooming region, or by detecting the input signals from the photo reflectors PR 1  and PR 2  when the zooming ring  18  is in the digital zooming region. Conventionally, the present focal length of the optical zooming has to be detected as shooting information even in the case of manual zooming; in the present embodiment, this focal length is detected using an encoder not shown.  
         [0073]     If it is determined that the zooming ring  18  has been operated, then it is determined whether the zooming ring  18  is located in the optical zooming region (step S 7 ). This determination can be made by detecting the presence or absence of the input signals from the photo reflectors PR 1  and PR 2 , as described above.  
         [0074]     The steps S 6  and S 7  are repeated as long as the zooming ring  18  is being operated in the optical zooming region. When the operation of the zooming ring  18  in the optical zooming region is completed, it is determined whether the shutter release button  22  is pressed halfway (step S 14 ); if it is pressed halfway, auto focusing is performed (step S 15 ). Next, it is determined whether the shutter release button  22  is fully depressed or not (step S 16 ); if it is fully depressed, image capturing is performed (step S 17 ), and the captured image is recorded (step S 18 ). Here, the steps S 14 , S 15 , and S 16  are repeated until it is determined that the shutter release button  22  is fully depressed.  
         [0075]     On the other hand, if it is determined in step S 7  that the zooming ring  18  is not located in the optical zooming region (that is, it has moved into the digital zooming region), the controller  42  switches the subject image viewing means from the optical viewfinder  30  to the rear monitor  32  to produce a live view display (step S 8 ), and activates the digital zooming (step S 9 ). Then, the controller  42  acquires the rotation angle (i.e., the amount of rotation) of the zooming ring  18  detected by the photo reflectors PR 1  and PR 2  (step S 10 ).  
         [0076]     Next, the controller  42  determines whether the mode is set to the linear mode or not (step S 11 ). If the mode is set to the linear mode, digital zooming is performed by determining the digital zooming magnification that matches the detected rotation angle of the zooming ring  18 , based on the rate of change calculated in step S 5  for the linear mode (step S 12 ). On the other hand, if the mode is set to the full range mode, digital zooming is performed by determining the digital zooming magnification that matches the detected rotation angle of the zooming ring  18 , based on the rate of change calculated in step S 5  for the full range mode (step S 13 ). In either mode, a live view display of the digitally zoomed subject image is produced on the rear monitor  32 .  
         [0077]     The above steps S 8  to S 13  are repeated until the operation of the zooming ring  18  in the digital zooming region is completed (step S 6  or S 7 ).  
         [0078]     When the operation of the zooming ring  18  in the digital zooming region is completed, it is determined whether the shutter release button  22  is pressed halfway (step S 14 ); if it is pressed halfway, auto focusing is performed (step S 15 ). Next, it is determined whether the shutter release button  22  is fully depressed or not (step S 16 ); if it is fully depressed, image capturing is performed (step S 17 ), and the captured image is recorded (step S 18 ). Here, the steps S 14 , S 15 , and S 16  are repeated until it is determined that the shutter release button  22  is fully depressed.  
         [0079]     In the case of a camera in which the lens barrel  14  is not an interchangeable type, since the focal length of the zooming lens and the optical zooming magnification are invariant and, therefore, need only be prestored in the controller  42 , the steps S 1  and S 3  in the flow chart of  FIG. 12  are not necessary.  
         [0080]     As described above, according to the digital camera  10  of the present embodiment, when the digital zooming switch  26  is ON, a smooth transition can be made from the optical zooming to the digital zooming by just operating the zooming ring  18 , and the camera thus achieves extremely simple and user friendly operation while eliminating the possibility of erroneous operation.  
         [0081]     The present invention is not limited to the portionicular embodiment described above, but various modifications can be made.  
         [0082]     For example, in the above digital camera  10 , the zooming ring  18  has been described as being rotated for operation, but alternatively, the camera may be constructed so that the zooming ring  18  is manually moved rectilinearly in the direction parallel to the optical axis of the zooming lens. In that case, the groove for guiding the cam follower pin  74  attached to the lens frame member holding the zooming lens is formed in the shape of a straight line, and the pin  27  as the restricting member engages in the straight-line groove at an intermediate point along the length thereof.  
         [0083]     Further, in the above digital camera  10 , the digital zoominging switch  26  has been described as being provided on the lens barrel  14 , but alternatively, a pushbutton type digital zoominging switch  26  may be provided, for example, on the camera body  12 . In that case, it is preferable that the pin  27  as the restricting member be operated, for example, by an electric driving means such as a solenoid, in synchronization with the ON operation of the digital zoominging switch  26 .  
         [0084]     The restricting member for restricting the rotation of the zooming ring  18  at the telephoto end position of the optical zooming is not limited to the pin  27 , but may be constructed from any other suitable means such as a lever, a block, or a rod member, and the motion to be given to the restricting member to cause it to engage in the cam groove  70  is not limited to rectilinear motion, but it may be constructed to engage in the cam groove  70  by being rotated.  
         [0085]     Further, in the above digital camera  10 , when the digital zooming is activated, the subject image has been presented for viewing as a live view display on the rear monitor  32 , but alternatively, a small display device may be provided within the camera body  12  so that the digitally zoomed subject image displayed on the small display device can be viewed through the viewfinder  30  by switching the viewfinder  30  from the optical viewfinder to the digital viewfinder. In that case, even when the zooming mode is switched from the optical zooming to the digital zooming, the user can continue to view the subject image through the viewfinder  30  without having to take his eye off the viewfinder  30 .  
         [0086]     Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications deportion from the scope of the present invention, they should be construed as being included therein.