Abstract:
An electronic device includes circuitry for carrying out an operation unrelated to camera operation, and camera circuitry for carrying out a camera related operation, the camera circuitry including circuitry for providing autofocus control. The electronic device further includes a camera lens operatively coupled to the camera circuitry, a focus state of the camera lens being controlled by the camera circuitry. In addition, the electronic device includes an operator input operatively coupled to at least the camera circuitry for enabling an operator to provide an input unrelated to focus control of the camera lens in a first operating condition, and to provide a manual focus control input to the camera lens in a second operating condition.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to portable electronic devices such as mobile phones, and more particularly to portable electronic devices having an auxiliary camera function. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Portable electronic devices such as mobile phones have been popular for years and yet only continue to increase in popularity. Traditionally, mobile phones had been used strictly for conventional voice communications. However, as technology has developed mobile phones are now capable not only of conventional voice communications, but also are capable of data communications, video transfer, media reproduction, commercial radio reception, etc. More and more, a user having a single electronic device such as a mobile phone is able to perform a variety of different functions. 
         [0003]    Many mobile phones today include a camera function for taking pictures. The pictures may be stored digitally in memory, transmitted over the carrier network, etc. As technology and manufacturing processes have improved, mobile phones nowadays are capable of capturing images at relatively high resolutions previously found only in dedicated cameras. This has resulted in mobile phones possessing even more sophisticated camera features. These features include, for example, macro operation, autofocus control, red-eye reduction, etc. 
         [0004]    Macro operation, as is known, involves taking photographs of an object at very close range. Ideally, the focal point of the camera lens is adjusted for very close range during macro photography. Unfortunately, mobile phones and other electronic devices that include autofocus control sometimes experience difficulty providing appropriate autofocus control especially during macro operation. This results in images that are out of focus, leading to user disappointment, etc. 
         [0005]    There are primarily two types of autofocus control, active and passive. In active autofocus control, the mobile phone transmits pulses of infrared (IR) or sonic energy. The object to be photographed reflects these pulses back toward the mobile phone where the pulses are received. The mobile phone determines the time of flight of the infrared or acoustic pulses, and computes the focal length to the object. Based on the computed focal length, the mobile phone adjusts the camera lens within the mobile phone so as to focus on the object. In passive autofocus control, the mobile phone processes the image data received by the camera lens and adjusts the lens to provide maximum sharpness/contrast in the image. 
         [0006]    In macro operation where the object may be only inches away, the pulses received by the mobile phone in active autofocus control may be reflected too quickly and/or from too many angles. In addition, or in the alternative, the object itself may be the source of noise that confuses the autofocus control (e.g., when photographing a candle flame that emits IR energy). Autofocus control within the mobile phone is oftentimes unable to process the reflections sufficiently. As a result, the autofocus control reverts to an “infinity focus” or focuses on the wrong point in the image, leaving the desired photograph subject out of focus. In the case of passive autofocus control, the mobile phone or other type electronic device simply may not have sufficient computational capacity to process and focus the image. Such computational capacity is typically reserved for higher-end, dedicated digital cameras. Consequently, the autofocus control of the mobile phone again will revert to “infinity focus” or focus on the wrong point in the image. 
         [0007]    As a result, there is a strong need for a mobile phone or other electronic device having an auxiliary camera function that has the ability to focus the camera even under circumstances where autofocus control may otherwise fail. While higher-end, dedicated digital cameras offer manual focus override capability, this is typically by way of the user manually rotating the lens barrel. Electronic devices having an auxiliary camera function typically do not include a lens barrel that the user may manually rotate in order to focus on an object. 
         [0008]    Moreover, it is undesirable simply to add additional control buttons or inputs to an electronic device to provide manual focus operation. There is a constant push for miniaturization of the electronic devices such as mobile phones to satisfy the convenience and desires of users. Simply adding additional control buttons or inputs can result in the need for increased surface area on the electronic device, which is undesirable. In addition, or in the alternative, adding additional control buttons or inputs can result in a reduction in the size of the other control buttons or inputs. This is undesirable as smaller buttons become more difficult for a user to operate. 
         [0009]    In view of the aforementioned shortcomings, there is a strong need in the art for a mobile phone or other electronic device that provides both autofocus and manual focus control without sacrificing size and/or convenience to the user. 
       SUMMARY 
       [0010]    According to one aspect of the invention, an electronic device is provided that includes circuitry for carrying out an operation unrelated to camera operation, and camera circuitry for carrying out a camera related operation, the camera circuitry including circuitry for providing autofocus control. The electronic device further includes a camera lens operatively coupled to the camera circuitry, a focus state of the camera lens being controlled by the camera circuitry. In addition, the electronic device includes an operator input operatively coupled to at least the camera circuitry for enabling an operator to provide an input unrelated to focus control of the camera lens in a first operating condition, and to provide a manual focus control input to the camera lens in a second operating condition. 
         [0011]    According to another aspect of the invention, the operator input in the first operating condition provides zoom control as part of the camera related operations. 
         [0012]    In accordance with another aspect of the invention, the camera circuitry comprises circuitry for determining whether the autofocus control is acceptable in accordance with a predefined criteria, and based on the determination automatically controls whether the operator input is operative in the first operating condition or the second operating condition. 
         [0013]    According to still another aspect of the invention, the circuitry for providing autofocus control provides active autofocus control. 
         [0014]    With still another aspect of the invention, the circuitry for providing autofocus control utilizes time of flight of transmitted and received pulses, and the predefined criteria is based on time of flight information obtained by the circuitry for providing autofocus control. 
         [0015]    In yet another aspect of the invention, the pulses are infrared light pulses. 
         [0016]    According to another aspect, the circuitry for providing autofocus control provides passive autofocus control. 
         [0017]    According to still another aspect of the invention, the predefined criteria is based on an evaluation of edge contrast. 
         [0018]    With still another aspect of the invention, the operator input is operative in the first operating condition or the second operating condition is based on an operator mode selection. 
         [0019]    In accordance with another aspect of the invention, the operator mode selection is a macro photography mode selection. 
         [0020]    According to another aspect of the invention, the operation unrelated to camera operation comprises mobile phone operation. 
         [0021]    According to still another aspect of the invention, the operator input is operative in the first operating condition to control a function of the mobile phone operation. 
         [0022]    In accordance with yet another aspect of the invention, the function comprises volume within the mobile phone operation. 
         [0023]    According to another aspect of the invention, the circuitry for carrying out an operation unrelated to camera operation and the camera circuitry are embodied at least in part within a common microcontroller. 
         [0024]    To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
         [0025]    It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a front perspective view of an electronic device in an exemplary embodiment of the present invention; 
           [0027]      FIG. 2  is a rear perspective view of the electronic device of  FIG. 1  in accordance with the exemplary embodiment of the present invention; 
           [0028]      FIG. 3  is a schematic block diagram of the electronic device of  FIGS. 1 and 2  in accordance with the exemplary embodiment of the present invention; 
           [0029]      FIG. 4  is a flowchart representing operation of auto/manual focus control in accordance with one embodiment of the present invention; 
           [0030]      FIG. 5  is a flowchart representing operation of auto/manual focus control in accordance with another embodiment of the present invention; 
           [0031]      FIGS. 6   a  and  6   b  represent typical zoom operation in accordance with the present invention; 
           [0032]      FIGS. 7   a  and  7   b  represent typical macro operation and zoom operation in accordance with the present invention; 
           [0033]      FIGS. 8   a  and  8   b  represent macro operation and manual focus based on zoom operation in accordance with the present invention; 
           [0034]      FIG. 9  represents a sample criteria for reverting to manual focus based on zoom operation in accordance with the present invention; and 
           [0035]      FIG. 10  represents another sample criteria for reverting to manual focus based on zoom operation in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0036]    The present invention will now be described with reference to the figures, wherein like reference numerals are used to refer to like elements throughout. 
         [0037]    Referring initially to  FIGS. 1 and 2 , an electronic device  20  is shown in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, the electronic device  20  is a mobile phone for carrying out mobile communications including voice communications, etc. In addition to operating as a mobile phone, the electronic device  20  also may function as a camera for taking photographs. While the present invention is described herein in the context of the electronic device  20  being a mobile phone, it will be appreciated that the electronic device  20  may be any type of electronic device having an auxiliary camera function (e.g., a personal digital assistant (PDA), personal media player, etc.). The particular type of electronic device is not germane to the present invention in its broadest sense. 
         [0038]    As is shown in  FIG. 1 , the exemplary embodiment of the mobile phone  20  includes a liquid crystal display  24  serving as a graphical user interface (GUI). The display  24  provides a display of various types of information as is conventional. For example, the display  24  may display the operational status of the phone  20 , contact information, menu information, text, graphics, images, videos, etc. When the mobile phone  20  is utilized as a camera as described herein, the display  24  may function as an electronic viewfinder to aid the user when taking a photograph. In addition, in the case where the display  24  is a touch sensitive display, the display  24  may serve as an input device to allow the user to input data, menu selections, etc. 
         [0039]    The mobile phone  20  further includes a microphone  26  and a speaker  28 . As is conventional, the microphone  26  and speaker  28  allow a user to carry out conventional voice communications by placing the phone  20  adjacent the user&#39;s ear. In addition, the mobile phone  20  includes a keypad  30  having an assortment of keys. The keypad  30  facilitates user input and operation of the mobile phone  20  as is conventional. For example, the keypad  30  may include keys for navigating the menus displayed on the display  24 , selecting predefined functions such as camera operation, initiating or terminating a call, etc. 
         [0040]    The mobile phone  20  also may include other keys or buttons useful in the operation of the mobile phone  20 . For example, the mobile phone  20  includes buttons  32   a  and  32   b  mounted on a side face of the mobile phone housing. During use of the mobile phone  20  as a telephone or media player, the buttons  32   a  and  32   b  serve as a convenient means to allow a user to adjust the volume up or down, respectively. In addition, the mobile phone  20  includes a button  34  that allows a user to answer or “pick up” an incoming call simply by pressing the button  34 . 
         [0041]    Furthermore, when the mobile phone  20  operates as a camera as discussed more fully below, the buttons  32   a  and  32   b  respectively function to increase and decrease the amount of zoom provided by the camera. The button  34 , on the other hand, functions as a shutter button. As is conventional, by depressing the button  34  only part way, autofocus control circuitry within the mobile phone  20  is able to lock in the camera auto focus. By depressing the button  34  completely, the camera shutter function is activated and a photograph taken. 
         [0042]      FIG. 2  illustrates a typical orientation of the mobile phone  20  when utilized as a camera. As is shown, the rear of the housing includes a slidable cover  40 . When open as shown in  FIG. 2 , the cover  40  exposes a camera lens  42  and an autofocus transducer  44 . When the cover  40  is closed, the camera lens  42  and autofocus transducer  44  are protected from dirt, dust, scratches, etc. The mobile phone  20  also includes a flash element  46  for providing light under low lighting conditions. 
         [0043]    As will be described in more detail below in relation to  FIG. 3 , the autofocus transducer  44  transmits pulses of infrared or ultrasonic energy towards an object to be photographed. The pulses are reflected off the object and travel back towards and are received by the autofocus transducer  44 . Those having ordinary skill in the art will appreciate how the time of flight of the pulses is related to the distance of the object from the mobile phone  20 . The mobile phone  20  utilizes the time of flight information to automatically focus the camera lens  42  to the appropriate focal length to photograph the object. 
         [0044]    In order to utilize the autofocus feature, the user points the lens  42  of the mobile phone  20  at the object and presses the button  34  part way. This causes the autofocus transducer  44  to emit and receive the infrared or sonic pulses, and the mobile phone  20  calculates the appropriate focal length setting and automatically adjusts the focus of the lens  42 . The user typically is notified that autofocus has been successfully achieved by way of a display icon or similar visual indicator provided in the display  24  serving as the electronic viewfinder. In addition, or in the alternative, the user may be notified that autofocus has been successfully achieved via an audible indicator such as a beep or the like. The user then takes the picture by pressing the button  34  the remainder of the way down in order to trigger the shutter function. 
         [0045]    The user adjusts the zoom setting by operating the buttons  32   a  and  32   b  when the mobile phone  20  is functioning as a camera. By pressing the buttons  32   a  and  32   b , the mobile phone  20  in one embodiment provides digital zoom in the sense that the image as displayed in the viewfinder and as captured by the camera is zoomed in or out by digitally manipulating the image data obtained via the camera lens  42 . In addition or in the alternative, in an embodiment of the mobile phone  20  where the camera lens  42  is a zoom lens, the mobile phone  20  provides optical zoom in the sense that the user may control the zoom setting of the lens  42  via the buttons  32   a  and  32   b.    
         [0046]    The mobile phone  20  as described thus far in relation to  FIGS. 1 and 2  operates conventionally and is constructed in substantially the same manner as conventional mobile phones having an auxiliary camera function. However, the mobile phone  20  of the present invention differs substantially from other mobile phones having an auxiliary camera function primarily in the following manner. A user may incur instances where the autofocus control of the mobile phone  20  is unable to achieve acceptable autofocus. As described above, for example, in macro operation where the object being photographed may be only inches away, the pulses received by the autofocus transducer  44  during active autofocus control may be reflected too quickly and/or from too many angles. In addition, or in the alternative, the object itself may be the source of noise that confuses the autofocus control (e.g., photographing a candle flame that emits IR energy). The autofocus control within the mobile phone  20  may be unable to process the reflections sufficiently. 
         [0047]    In accordance with the present invention, the mobile phone  20  detects when the autofocus control is unable to focus satisfactorily. Upon detecting such condition, the mobile phone  20  automatically reconfigures the operation of the buttons  32   a  and  32   b  so as to provide manual focus control in place of the ordinary zoom control. Thus, by pressing the buttons  32   a  and  32   b  the user can adjust the focal length of the camera lens  42  while viewing the object through the viewfinder (e.g., the display  24 ). The user can focus on the object via the buttons  32   a  and  32   b  and upon achieving the desired focus, take the photograph by depressing the button  34  to activate the shutter function. 
         [0048]    The mobile phone  20  preferably notifies the user of the inability to autofocus satisfactorily and the need to focus manually. For example, the mobile phone  20  may notify the user visually by displaying an alert via the viewfinder (e.g., the display  24 ). In addition or the alternative, the mobile phone  20  may notify the user via an audible indicator that preferably is different from any audible indicator used to indicate the auto focus control has been successfully achieved. 
         [0049]    As will be appreciated, such operation of the mobile phone  20  allows the user to manually focus the camera lens  42  without necessitating the addition of one or more control buttons or inputs. Simply adding additional control buttons or inputs, as noted above, can result in the need for increased surface area on the mobile phone  20  or the reduction in the size of the other control buttons or inputs, both of which are undesirable. Instead, the mobile phone  20  in accordance with the present invention allows an existing control input that ordinarily is not associated with a manual focus operation (e.g., the zoom/volume control buttons  32   a  and  32   b ) to function as a manual focus control input automatically under circumstances in which the autofocus control cannot achieve satisfactory focus. The present invention is described herein in relation to the zoom/volume control buttons  32   a  and  32   b  also functioning as manual focus inputs when autofocus is unavailable. However, those having ordinary skill will appreciate that the present invention equally encompasses other control inputs (e.g., buttons or keys) on the mobile phone  20  having an ordinary function unrelated to manual focus yet serving as manual focus inputs similar to the zoom/volume control buttons  32   a  and  32   b  in the event the autofocus control cannot obtain satisfactory focus. 
         [0050]      FIG. 3  represents a functional block diagram of the mobile phone  20  in accordance with the present invention. The construction of the mobile phone  20  is generally conventional with the exception of the auto/manual focus control capabilities described herein. Preferably, such capabilities are implemented primarily via software within the mobile phone  20 . However, it will be apparent to those having ordinary skill in the art that such operation can be carried out via primarily software, hardware, firmware, or combinations thereof, without departing from the scope of the invention. 
         [0051]    The mobile phone  20  includes a primary control circuit  60  that is configured to carry out overall control of the functions and operations of the mobile phone  20 . The control circuit  60  may include a CPU, microcontroller, or microprocessor, etc., collectively referred to herein simply as a CPU  62 . The CPU  62  executes code stored in memory (not shown) within the control circuit  60 , and/or in a separate memory  64  in order to carry out conventional operation of the mobile phone functions  65  within the mobile phone  20 . In addition, the CPU  62  executes code similarly stored in memory to carry out the camera functions  66  and autofocus functions  68  described herein. 
         [0052]    Continuing to refer to  FIG. 3 , the mobile phone  20  includes an antenna  70  coupled to a radio circuit  72 . The radio circuit  72  includes a radio frequency transmitter and receiver for transmitting and receiving signals via the antenna  70  as is conventional. The mobile phone  20  further includes a sound processing circuit  74  that processes the audio signal transmitted by/received from the radio circuit  72 . In addition, the sound processing circuit  74  serves to process an audio signal provided by the control circuit  60  during playback of media files, for example. Also coupled to the sound processing circuit  74  are the aforementioned microphone  26  and speaker  28 , and a headset jack  75 , for example. The radio circuit  72  and sound processing circuit  74  are each coupled to the control circuit  60  that carries out overall operational control. 
         [0053]    The mobile phone  20  also includes the aforementioned display  24 , keypad  30 , buttons  32   a  and  32   b , and button  34  coupled to the control circuit  60 . The mobile phone  20  further includes an I/O interface  76 . The I/O interface  76  may be in the form of any one of many typical mobile phone I/O interfaces, such as a multi-element connector at the base of the mobile phone  20 . As is typical, the I/O interface  76  may be used to couple the mobile phone  20  to a battery charger to charge a power supply unit (e.g., battery)  78  within the mobile phone  20 . Further, the I/O interface  76  may serve to connect the mobile phone  20  to a personal computer or other device via a data cable, etc., in order to download photographs or perform various other operations. As another alternative, the I/O interface  76  may serve to connect the mobile phone  20  to a docking station including an audio amplifier, speakers and/or video display to allow for enhanced viewing/listening of the media objects as part of a media player function. 
         [0054]    As previously described, the mobile phone  20  includes the camera lens  42 . The camera lens  42  serves to image an object(s) to be photographed onto an image capture device such as a charge-coupled device (CCD) array  80  included in the mobile phone  20 . Images received by the CCD  80  are input to an image processing circuit  82  included in the mobile phone  20 . Using conventional techniques, the image processing circuit  82  provides appropriate processing of the images under the control of the camera functions  66  so that photographs taken during camera operation are processed and stored in memory  64 , for example. 
         [0055]    The camera lens  42  preferably includes two or more lens elements  84 . The relative positioning of the lens elements  84  with respect to each other and/or the CCD  80  may be adjusted mechanically via small motors or other electromechanical moving means (e.g., voice coil, piezoelectric element, etc.) (not shown) included in the camera lens  42 . In the exemplary embodiment, a motor driver  86  included in the mobile phone  20  controls the positions of the lens elements  84 . The motor driver  86  is responsive to control signals from the control circuit  60  and adjusts the positions of the lens elements  84  in accordance with the control signals. 
         [0056]    By adjusting the positions of the lens elements  84 , the mobile phone  20  is able to control the focal length or focus of the camera lens  42 . In an embodiment where the camera lens  42  is also a zoom lens, the mobile phone  20  is also able to control the amount of optical zoom provided during a given photograph. In an embodiment where the camera lens is not a zoom lens, the mobile phone  20  is still able to control the amount of digital zoom by increasing/decreasing the relative size of the image digitally as is conventional. 
         [0057]    The particular operating mode of the mobile phone  20  is controlled by user selection via the keypad  30 , menu selections via the display  24 , etc., as is conventional. Upon being configured for operation of the mobile phone  20  as a phone, the user may press the button  34  in order to pick up an incoming call, for example. The button  34  provides an input control signal to the phone functions  65  which interpret the control signal as a request to pick up the incoming call. The input control signal from the button  34  is also input to the camera functions  66 . During operation of the mobile phone  20  as a phone, however, the control circuit  60  is configured such that the camera functions  66  disregard the input from button  34 . Conversely, upon the mobile phone  20  being configured for operation as a camera, the control circuit  60  enables the camera functions  66  to receive the input control signal from the button  34  as an autofocus/shutter control button. At the same time, the phone functions  65  disregard the input from the button  34 . 
         [0058]    Similarly, when the mobile phone  20  is configured as a phone, the phone functions  65  receive the inputs from buttons  32   a  and  32   b  and interpret such inputs to control the volume of the speaker  28  for telephone conversations. While the inputs from the buttons  32   a  and  32   b  are also received by the camera functions  66 , the camera functions  66  disregard such inputs. On the other hand, when the mobile phone  20  is configured to function as a camera, the control circuit  60  is designed such that the camera functions  66  ordinarily interpret the inputs from the buttons  32   a  and  32   b  as controls for increasing or decreasing the amount of zoom. The phone functions  65  disregard the inputs from the buttons  32   a  and  32   b  during camera operation. 
         [0059]    When wishing to take a picture with the mobile phone  20  operating as a camera, a user directs the lens  42  towards the object to be photographed as previously explained. In this particular example, the image received by the CCD sensor  80  is provided to the display  24  via the camera functions  66  so as to function as an electronic viewfinder. As will be appreciated, another embodiment of the invention may utilize a simple optical viewfinder or the like without departing from the scope of the invention. 
         [0060]    As the user depresses the button  34  partially to initiate autofocus control, the camera functions  66  detect such input and requests that the autofocus functions  68  perform conventional autofocus control. In order to do so, the autofocus functions  68  cause the autofocus transducer  44  to emit and receive infrared pulses or the like. The autofocus functions  68  process the pulses received by the autofocus transducer  44  in order to determine the time of flight of the pulses reflected by the object and thus determine the distance between the mobile phone  20  and the object. In accordance with an exemplary embodiment of the present invention, provided the time of flight calculated by the autofocus functions  68  is equal to or greater than some predetermined amount indicative of the object being sufficiently far away for proper focus, the autofocus functions  68  communicates to the camera functions  66  the determined focal length between the mobile phone  20  and the object being photographed. The camera functions  66  in turn provides control signals to the motor driver  86  which in turn adjusts the positioning of the lens elements  84  to provide proper focus of the object. 
         [0061]    At the same time, if the user wishes to zoom in or out relative to the object, the user may press the buttons  32   a  and/or  32   b  to control the zoom. The camera functions  66  receive the control inputs from the buttons  32   a  and  32   b  and manipulate the zoom either optically or digitally as described above. Once the user has selected the desired zoom amount and receives an indication from the camera functions  66  that autofocus control has been locked in, the user may depress the button  34  fully to activate the shutter function. At such time, the image on the CCD  80  is captured and stored in memory  64 . 
         [0062]    On the other hand, if when the user depresses the button  34  partially for autofocus operation the autofocus functions  68  are unable to achieve satisfactory focus (e.g., the calculated time of flight is less than the predetermined amount), the autofocus functions  68  notify the camera functions  66  that satisfactory focus cannot be achieved. The camera functions  66  in turn notify the user (e.g., via a visual or audible indicator) that autofocus has not been achieved. In addition, the camera functions  66  are configured automatically in such instance to interpret inputs from the buttons  32   a  and  32   b  as manual focus control signals. Specifically, by pressing the buttons  32   a  and  32   b , the user can adjust the focus of the lens  42  in and out, respectively. 
         [0063]    More particularly, the camera functions  66  receive the inputs from the buttons  32   a  and  32   b  and in response control the relative positions of the lens elements  84  via the motor driver  86  to allow the user to manually focus the lens  42 . By viewing the object via the CCD  80  and electronic viewfinder display  24 , for example, the user may adjust the lens  42  via the buttons  32   a  and  32   b  until the object becomes optimally focused. The user can then capture the photograph by fully depressing the button  34  to activate the shutter function. The camera functions  66  may then reconfigure the mobile phone  20  for conventional autofocus control unless and until the autofocus functions  68  are again unable to achieve satisfactory focus as described above. 
         [0064]    In another embodiment of the invention, the autofocus functions  68  utilize passive autofocus techniques in place of the autofocus transducer  44 . For example, the autofocus functions  68  may analyze the image provided by the CCD  80  during autofocus. By analyzing the image in combination with adjusting the lens  42  via the camera functions  66  and motor driver  86 , the autofocus functions  68  attempt to maximize edge contrast between objects in the image. The sharper the edge contrast, for example, the better focus. If the autofocus functions  68  are able to achieve a maximum edge contrast equal to or greater than a predetermined amount, the autofocus operation is considered satisfactory. The autofocus functions  68  indicate to the camera functions  66  that autofocus has been satisfactorily achieved. Again, the user is notified and the photograph may be taken by fully pressing the button  34  to activate the shutter operation. The buttons  32   a  and  32   b  remain operative to control zoom. Conversely, if the autofocus functions  68  are unable to achieve a maximum edge contrast equal to or greater than the predetermined amount, the autofocus functions  68  notify the camera functions  66  that autofocus has not been achieved. Therefore, again the camera functions  66  notify the user and now automatically interpret the inputs from buttons  32   a  and  32   b  as manual focus control instead of zoom control. Thus, the user may manually focus the photograph. 
         [0065]      FIG. 4  is a flowchart describing the operation of the present invention in relevant part. Assuming the mobile phone  20  is in the camera function mode, step  100  represents a user activating the autofocus control such as by pressing the button  34  only partially. Those having ordinary skill in the art will appreciate, however, that the autofocus control may be activated by some other means without departing from the scope of the present invention. Following step  100 , the mobile phone  20  proceeds to step  102  in which the autofocus functions  68  determine if autofocus is satisfactorily achieved (e.g., by TOF or edge contrast criteria) as described above. If yes, the mobile phone  20  proceeds to step  104  in which conventional autofocus control is utilized and zoom control via buttons  32   a  and  32   b  is available. 
         [0066]    If in step  102  the autofocus functions  68  determine that autofocus is not satisfactorily achieved (e.g., by TOF or edge contrast criteria) as described above, the mobile phone  20  proceeds to step  106  rather than step  104 . In step  106 , the mobile phone  20  notifies the user that satisfactory autofocus has not been achieved and manual focus is available. Then, as represented in step  108 , the mobile phone  20  provides manual focus control via the buttons  32   a  and  32   b.    
         [0067]      FIG. 5  illustrates operation of the mobile phone  20  in accordance with another embodiment of the invention. In this particular embodiment, whether conventional autofocus or manual focus via the buttons  32   a  and  32   b  is provided is controlled simply by whether the user places the mobile phone  20  in a macro photography mode. If the user selects macro photography operation by way of the keypad  30 , menu selections via the display, or the like, the camera functions  66  automatically revert to operation in which the buttons  32   a  and  32   b  provide manual focus control. 
         [0068]    Thus, step  110  of  FIG. 5  represents the camera functions  66  determining whether the user has selected macro photography operation. If no, the mobile phone  20  proceeds to step  112  in which the mobile phone carries out conventional autofocus control and zoom control is available via the buttons  32   a  and  32   b , similar to step  104  in the embodiment of  FIG. 4 . If yes in step  110 , the mobile phone proceeds to step  114  in which the mobile phone  20  notifies the user that autofocus has not been achieved and manual focus is available similar to step  106  in  FIG. 4 . Then, as represented in step  116 , the mobile phone  20  provides manual focus control via the buttons  32   a  and  32   b  similar to step  108  in  FIG. 4 . 
         [0069]      FIGS. 6   a - 6   b ,  7   a - 7   b  and  8   a - 8   b  represent the operation of the mobile phone in accordance with the present invention from the perspective of what may be seen via the display  24  serving as an electronic viewfinder. Referring initially to  FIGS. 6   a - 6   b , shown is typical operation of the mobile phone  20 .  FIG. 6   a  illustrates a view of a city skyline. An icon on the display indicates the level of zoom employed.  FIG. 6   b  represents the view following the user increasing the amount of zoom via the buttons  32   a  and  32   b.    
         [0070]      FIG. 7   a  illustrates a view of a leaf with a given amount of zoom during macro photography.  FIG. 7   b  represents the leaf with an increased amount of zoom via the buttons  32   a  and  32   b.    
         [0071]      FIG. 8   a  represents a view of the leaf in the event the autofocus control is unable to satisfactorily focus on the leaf as described above. Alternatively, autofocus control may simply not be available as a result of the mobile phone  20  being in macro operation as in the embodiment of  FIG. 5 . In either case, the mobile phone  20  reverts to manual focus control as represented in  FIG. 8   b . Note how the viewfinder includes an icon indicating that the mobile phone  20  is now being manually focused. By adjusting the buttons  32   a  and  32   b  as represented by the zoom/focus menu bar, a user may achieve satisfactory focus manually as shown in  FIG. 8   b.    
         [0072]      FIGS. 9 and 10  graphically illustrate exemplary criteria for changing between autofocus and manual focus in accordance with the present invention.  FIG. 9  represents how manual focus via the buttons  32   a  and  32   b  is provided in the event a measured TOF of the autofocus transducer  44  pulses is less than a predefined criteria. Otherwise, conventional zoom operation is provided via the buttons  32   a  and  32   b .  FIG. 10  represents the case where control is based on the maximum peak contrast achieved via passive autofocus control as described above. 
         [0073]    While the present invention is described above in the context of volume control/zoom control buttons  32   a  and  32   b  serving as manual focus control buttons, those having ordinary skill in the art will appreciate that controls associated with other functions may instead serve as the manual focus control buttons in the event satisfactory autofocus is not achieved. The present invention is not intended to be limited in its broadest sense to the specific embodiments described herein. 
         [0074]    The term “electronic device” as referred to herein includes portable radio communication equipment. The term “portable radio communication equipment”, also referred to herein as a “mobile radio terminal”, includes all equipment such as mobile phones, pagers, communicators, e.g., electronic organizers, personal digital assistants (PDAs), smartphones or the like. 
         [0075]    Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the following claims.