JP2010101951A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To photograph images which are in focus of an object without fail, by eliminating the time lag generated in manual photograph, when fixing the focal distance to be photographed. <P>SOLUTION: An imaging apparatus includes: an imaging means for obtaining images, on the basis of light images concerning an object; a display means for displaying the images obtained with the imaging means; a setting means for setting a focus evaluation value which is regarded as triggers of photographing with the imaging means; a focus evaluation obtaining means for obtaining a current focus evaluation value, during display of monitoring images displayed on the display means by being obtained with the imaging means; and a control means for controlling so as to be photographed with the imaging means, when the difference between the current focus evaluation value obtained with the focus evaluation obtaining means and a focus evaluation value set with the setting means lies within a prescribed range, when the focal distance to be photographed is to be fixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus. More specifically, the present invention relates to an imaging apparatus that performs imaging with a fixed focal length.

  In a digital still camera (hereinafter, also referred to as a digital camera or a camera) that captures a subject image using an image sensor such as a CDD, a high-frequency component corresponding to a contrast signal is extracted from an image-captured signal, and the lens position at which this high-frequency component is maximized A focus adjustment method (mountain climbing method) in which the focus lens is moved is known. The high-frequency component is called a focus evaluation value (AF evaluation value). As the focus evaluation value, for example, a difference square value obtained by squaring a difference in luminance value of adjacent pixels in a range to be focused is set to all adjacent pixels. The sum of squared differences obtained by adding all the obtained squared differences is used.

  As a technology that uses such a focus adjustment method and further improves the autofocus (hereinafter referred to as AF) accuracy, for example, Patent Document 1 discloses the position and size of an acquisition region (area) for detecting an AF evaluation value. There has been disclosed an imaging apparatus that attempts to perform an accurate AF operation without being affected by the size of the subject or its unevenness by changing according to the subject.

  Also, in Patent Document 2, if a shooting distance is specified in advance before shooting, and then a subject is specified, the focused state is maintained even if the subject moves, and is acquired sequentially by the imaging means. An image pickup apparatus is disclosed that performs main shooting at a timing when a subject is within an allowable distance range corresponding to a specified shooting distance while displaying an image to be displayed.

JP 2008-520222 A JP 2005-215373 A

  However, the technique described in Patent Document 1 has a problem in that it takes time to focus and easily miss a photo opportunity because the peak of the AF evaluation value is unknown unless a scanning operation is performed. In particular, in the case of close-up photography of flowers, insects, and the like in macro photography, even a compact digital camera becomes a problem because the depth of field is so shallow that severe operation is required.

  Therefore, in the scene where the focusing operation is performed and the release is performed, for example, when the scanning operation ends and the stage of photographing is reached due to the factors of the subject such as the flower moving due to the wind or the insect already moving The problem is that they do not match.

  Also, for example, even when the subject is fixed, when the scanning operation is completed and the stage of shooting is reached, the photographer himself cannot continue to fix the camera, and the distance between the subject and the camera changes from the time of scanning. Problem arises. If a tripod or the like is used, the camera can be fixed. However, it is desirable that a compact digital camera or the like with emphasis on portability can be photographed immediately when it is in focus even without a tripod or the like.

  In order to solve these problems, digital cameras having a mode for shooting with a fixed focal length (referred to as a manual focus mode, a fixed focal length mode, a fixed focus mode, etc.) are also widely used. However, in any of the above-described scenes, there is a time lag between when the photographer recognizes that the focus has been met and when a shooting instruction is given by an operation such as pressing the release button.

  In addition, the technique described in Patent Document 2 includes a technique of tracking a subject, and there is a problem that the cost of hardware becomes high in order to perform subject tracking with high accuracy and high speed. Furthermore, there is a problem that it is difficult to deal with a situation where tracking is difficult, such as when the subject being tracked deviates from the field of view of the camera and then reenters the field of view. Furthermore, although it is described that the actual photographing is performed at the timing when the subject is within the allowable distance range corresponding to the designated photographing distance, the degree of focusing on the subject cannot be arbitrarily changed. There's a problem.

  Therefore, the present invention occurs in the case of manual shooting by automatically determining that focusing has been performed at a preset position on the screen and shooting immediately in a mode in which shooting is performed with a fixed focal length. An object of the present invention is to provide an image pickup apparatus that can shoot an image in which a subject is in focus with a simple configuration without a time lag.

  In order to achieve this object, an imaging apparatus according to claim 1 includes an imaging unit that acquires an image based on a light image related to a subject, a display unit that displays an image acquired by the imaging unit, and an imaging unit. A focus evaluation value acquisition means for acquiring a current focus evaluation value during display of a monitoring image acquired by the imaging means and displayed on the display means; When shooting at a fixed distance, the imaging means takes a picture when the difference between the current focus evaluation value acquired by the focus evaluation value acquisition means and the focus evaluation value set by the setting means falls within a predetermined range. And a control means for performing control.

  According to a second aspect of the present invention, in the imaging apparatus according to the first aspect, the focus evaluation value acquisition unit acquires a current focus evaluation value based on data in a focus evaluation value determination area set in the display unit. To do.

  According to a third aspect of the present invention, in the imaging apparatus according to the second aspect of the present invention, the imaging apparatus further includes a correction unit that corrects the focus evaluation value set by the setting unit based on the luminance in the focus evaluation value determination area. The means controls the imaging means to take a picture when the difference between the current focus evaluation value and the focus evaluation value corrected by the correction means falls within a predetermined range.

  According to a fourth aspect of the present invention, in the imaging apparatus according to any one of the first to third aspects, the peak value of the focus evaluation values acquired by the focus evaluation value acquisition unit during display of the monitoring image is stored. Storage means is further provided, and the setting means sets the peak value stored in the storage means as the focus evaluation value.

  According to a fifth aspect of the present invention, in the imaging apparatus according to any one of the second to fourth aspects, the focus evaluation value determination area can be set at an arbitrary position at an arbitrary position of the display means. It is.

  According to a sixth aspect of the present invention, in the imaging apparatus according to any one of the first to fifth aspects, the setting means sets a plurality of focus evaluation values.

  According to a seventh aspect of the present invention, in the imaging apparatus according to any one of the first to sixth aspects, the setting means sets a threshold at a time when the current focus evaluation value exceeds a focus evaluation value that triggers photographing. Is set.

  According to an eighth aspect of the present invention, in the imaging apparatus according to any one of the first to seventh aspects, the setting means sets an upper limit value of the number of shots when performing continuous shooting.

  According to a ninth aspect of the present invention, in the imaging apparatus according to any one of the first to eighth aspects, the setting means sets a time interval until the photographing is started again after one photographing. Is.

  According to the present invention, in a mode in which shooting is performed with a fixed focal length, it is generated in the case of manual shooting by automatically determining that focus has been achieved at a preset position on the screen and shooting immediately. An object of the present invention is to provide an image pickup apparatus that can easily shoot a good image in which the time lag is eliminated and the subject is in focus, with a simple configuration.

  Hereinafter, the configuration of the present invention will be described in detail based on the embodiment shown in FIGS.

1. Configuration of Imaging Device In this embodiment, a digital camera will be described as an example of an imaging device. FIG. 1 shows an external view of a digital camera, (a) shows a top view of the camera, (b) shows a front view of the camera, and (c) shows a rear view of the camera. FIG. 2 is a block diagram of a control system of the digital camera.

  As shown in FIG. 1A, the upper surface of the camera has a sub LCD 1, a release button 2 (SW1), and a mode dial 4 (SW2).

  As shown in FIG. 1B, a strobe light emitting unit 3, a distance measuring unit 5, a remote control light receiving unit 6, a lens barrel unit 7, and an optical viewfinder (front) 11 are provided in front of the camera. .

  The memory card throttle 121 indicates a throttle for inserting the memory card 121-1, and is provided on the side of the camera. The memory card 121-1 may be a LAN card 121-2, a wireless LAN card 121-3, or the like depending on circumstances.

  Further, as shown in FIG. 1C, on the back side of the camera, an AFLED (autofocus LED) 8, a strobe LED 9, an LCD monitor 10, an optical viewfinder (back side) 11, and a zoom button TELE12 (SW4) are provided. , A power switch 13 (SW13), a zoom button WIDE14 (SW3), and a reproduction switch 15 (SW6).

  Further, on the back of the camera, a self-timer / deletion switch 16 (SW5), a MENU / OK switch 17 (SW12), a left / image confirmation switch 18 (SW11), a lower / macro switch 19 (SW10), and an upper / Strobe switch 20 (SW7), right switch 21 (SW8), and display switch 22 (SW9) for displaying an image.

2. Next, various operations of the digital camera will be described with reference to FIG.

  The strobe light emitting unit 3 and the strobe circuit 114 compensate the light amount when light such as natural light is insufficient. In shooting in a dark place or when the subject is dark, the digital still camera processor 104 transmits a strobe light emission signal to the strobe circuit 114, and the strobe circuit 114 emits the strobe light emitting unit 3 to brighten the subject.

  The distance measuring unit 5 measures the distance between the camera and the subject. In a digital camera, a CCD-AF system is used in which the contrast of an image formed on an image sensor (CCD) is detected, and the lens is moved to a position with the highest contrast to adjust the focus. However, in the CCD-AF method, there is a problem that the focusing operation is slow because the lens is moved little by little to find the contrast. Therefore, the distance information with the subject is always obtained by using the distance measuring unit 5, and the lens is obtained from the distance information. The focus operation is speeded up by moving at once. The remote control light receiving unit 6 receives an infrared signal from the outside.

  The lens barrel unit 7 includes a zoom lens 7-1a for capturing an optical image of a subject, a zoom optical system 7-1 including a zoom drive motor 7-1b, a focus optical system including a focus lens 7-2a, and a focus drive motor 7-2b. 7-2, an aperture unit 7-3 including an aperture 7-3a, an aperture motor 7-3b, a mechanical shutter 7-4, a mechanical shutter unit 7-4b including a mechanical shutter motor 7-4a, and a motor driver 7- driving each motor. 5

  The motor driver 7-5 is driven and controlled by a drive command from the CPU block 104-3 in the digital still camera processor 104 based on the input from the remote control light receiving unit 6 and the operation input from the operation unit key unit (SW1 to SW13). Is done. The ROM 108 stores a control program and parameters for control, which are described in codes readable by the CPU block 104-3. By using a rewritable flash ROM for the ROM 108, the control program and parameters for control can be changed, and the function version can be easily upgraded.

  When the power of the digital camera is turned on, the CPU block 104-3 controls the operation of each part of the apparatus according to the control program and temporarily stores data necessary for the control in the RAM 107 and the digital still camera processor 104. Save to the Local SRAM 104-4.

  The CCD 101 is a solid-state imaging device for photoelectrically converting an optical image. The F / E (front end) -IC 102 includes a CDS 102-1 that performs correlated double sampling for image noise removal, an AGC 102-2 that performs gain adjustment, an A / D 102-3 that performs digital signal conversion, and a CCD1 control block 104-. 1 is supplied with a vertical synchronizing signal (hereinafter referred to as VD) and a horizontal synchronizing signal (hereinafter referred to as HD), and generates drive timing signals for the CCD 101 and the F / E-IC 102 controlled by the CPU block 104-3. TG102-4.

  The digital still camera processor 104 (hereinafter also referred to as the processor 104) performs white balance setting and gamma setting on the output data of the F / E-IC 102 from the CCD 101, and supplies a VD signal and an HD signal to the CCD1 signal processing block 104. −1, CCD2 signal processing block 104-2 that performs conversion to luminance data and color difference data by filtering processing, CPU block 104-3 that controls the operation of each part of the apparatus, and local that temporarily stores data necessary for control, etc. SRAM 104-4, USB block 104-5 for USB communication with an external device such as a personal computer, serial block 104-6 for serial communication with an external device such as a personal computer, JPEG CODEC block 104-7 for JPEG compression / decompression, image The size of the data A RESIZE block 104-8 that enlarges / reduces by interpolation processing, a TV signal display block 104-9 that converts image data into a video signal for display on an external display device such as a liquid crystal monitor or TV, and recorded image data are recorded. A memory card controller block 104-10 for controlling the memory card.

  The SDRAM 103 temporarily stores image data when the digital still camera processor 104 performs various processes on the image data. The stored image data is, for example, “RAW-RGB image data in a state in which white balance setting and gamma setting are performed in the CCD 1 signal processing block 104-1 from the CCD 101 via the F / E-IC 102. "YUV image data" in which luminance data / color difference data conversion has been performed in the CCD2 signal processing block 104-2, "JPEG image data" that has been JPEG-compressed in the JPEG CODEC block 104-7, and the like.

  The memory card throttle 121 is a throttle for mounting a removable memory card. The built-in memory 120 is a memory for storing captured image data even when no memory card is attached to the memory card throttle 121.

  The LCD driver 117 is a drive circuit that drives the LCD monitor 10, and also has a function of converting the video signal output from the TV signal display block 104-9 into a signal for display on the LCD monitor 10. The LCD monitor 10 is a display unit for monitoring the state of a subject before photographing, confirming a photographed image, and displaying image data recorded in the memory card 121-1 or the built-in memory 120.

  The video AMP 118 is an amplifier for converting the impedance of the video signal output from the TV signal display block 104-9 to 75Ω. The video jack 119 is a jack for connecting to an external display device such as a TV. The USB connector 122 is a connector for performing USB connection with an external device such as a personal computer.

  The serial driver circuit 123-1 is a circuit for converting the voltage of the output signal of the serial block 104-6 in order to perform serial communication with an external device such as a personal computer. The RS-232C connector 123-2 is a connector for performing serial connection with an external device such as a personal computer.

  The SUB-CPU 109 is a CPU in which ROM / RAM is built in one chip, and outputs the output signals of the operation key units (SW1 to SW13) and the remote control light receiving unit 6 to the CPU block 104-3 as user operation information. The camera state output from the CPU block 104-3 is converted into control signals for the sub LCD 1, AF LED 8, strobe LED 9, and buzzer 113 and output.

  The sub LCD 1 is a display unit for displaying the number of shootable images and the like, and the LCD driver 111 is a drive circuit for driving the sub LCD 1 based on an output signal of the SUB-CPU 109.

  The AF LED 8 is an LED for displaying an in-focus state at the time of photographing, and the strobe LED 9 is an LED for representing a strobe charging state. The AF LED 8 and the strobe LED 9 may be used for another display application such as when a memory card is being accessed. The operation key units (SW1 to SW13) are key circuits operated by the user, and the remote control light receiving unit 6 is a signal reception unit of the remote control transmitter operated by the user.

  The voice recording unit 115 includes a microphone 115-3 for inputting a voice signal by the user, a microphone AMP 115-2 for amplifying the input voice signal, and a voice recording circuit 115-1 for recording the amplified voice signal. The audio reproduction unit 116 is an audio reproduction circuit 116-1 that converts a recorded audio signal into a signal that can be output from the speaker 116-3, and an audio AMP 1162 that amplifies the converted audio signal and drives the speaker 116-3. And a speaker 116-3 for outputting an audio signal.

  The Ethernet (registered trademark) connection circuit (or wireless Ethernet connection circuit) 130 and the LAN connector 131 perform communication processing with an external device via a network using a communication protocol. In the case of an Ethernet connection circuit, communication processing is performed with an external device via a wired network, and in the case of a wireless Ethernet connection circuit, communication processing is performed with an external device via a wireless network.

3. Setting Unit Next, the setting unit included in the imaging apparatus of the present invention will be described with reference to FIGS. The setting means includes a processor 104, a RAM 107, a ROM 108, and the like, and at least a focus evaluation value (hereinafter referred to as “imaging trigger focus evaluation value”) to be compared with a focus evaluation value acquired by a focus evaluation value acquisition means described later. Is set.

  In addition, the “continuous number of shots” that indicates the upper limit of the number of shots when performing continuous shooting and the “interval” that indicates the time interval from when one shot is taken until automatic shooting is started again are set. It is preferable to do. Note that the “number of continuous shots” may be set as appropriate according to the capacity of the storage means such as the ROM 108. In this way, it is possible to perform photographing suitable for various photographing needs and various photographing environments of the photographer. For example, it is possible to avoid inadvertent continuous shooting in a focused state.

  First, when the digital camera is turned on, the MENU / OK switch 17, the left / image confirmation switch 18, the lower / macro switch 19, the upper / strobe switch 20, and the right switch 21 are operated by the photographer. As a result, the fixed focus automatic photographing setting screen (FIGS. 3 to 6, hereinafter also referred to as setting screen) is displayed on the display means (LCD monitor 10).

  On the setting screen, it is possible to set the above three parameters of “continuous shooting number”, “interval”, and “shooting trigger focus evaluation value”. Hereinafter, an example of an operation method on the fixed focus automatic photographing setting screen will be described.

  First, when the setting screen is displayed, the setting value of each parameter at that time point (initial value when not set) is displayed and the “number of continuous shots” can be changed (FIG. 3). ). If the up / strobe switch 20 is pressed in this state, the number of shots increases, and if the down / macro switch 19 is pressed, the number of shots decreases.

  When the right switch 21 is pressed, “interval“ minute ”” can be changed as shown in FIG. 4, and when the left / image confirmation switch 18 is pressed, “shooting trigger focus evaluation value” is displayed as shown in FIG. "Is ready to be changed.

  In a state in which the “interval“ minute ”” shown in FIG. 4 can be changed, the value of “minute” increases when the up / strobe switch 20 is pressed, and the value of “minute” decreases when the down / macro switch 19 is pressed. . Further, when the right switch 21 is pressed, “interval“ second ”” can be changed as shown in FIG. 5, and when the left / image confirmation switch 18 is pressed, “continuous shot number” is set as shown in FIG. It can be changed.

  In the state in which “interval“ second ”” shown in FIG. 5 can be changed, the value of “second” increases when the up / strobe switch 20 is pressed, and the value of “second” decreases when the down / macro switch 19 is pressed. . When the right switch 21 is pressed, the “shooting trigger focus evaluation value” can be changed as shown in FIG. 6, and when the left / image confirmation switch 18 is pressed, “interval“ minute ”is displayed as shown in FIG. "Is ready to be changed.

  In a state in which the “shooting trigger focus evaluation value” shown in FIG. 6 can be changed, when the up / strobe switch 20 is pressed, a vertical bar display square icon is raised, and when the down / macro switch 19 is pressed, the up / down bar display is displayed. The square icon goes down. This square icon indicates that the currently set “shooting trigger focus evaluation value” is a larger numerical value, and the lower the icon, the lower the “shooting trigger focus evaluation value”. Show.

  When the right switch 21 is pressed, the “continuous number of shots” can be changed as shown in FIG. 3, and when the left / image confirmation switch 18 is pressed, “interval“ seconds ”is displayed as shown in FIG. It can be changed.

  Here, in any state shown in FIGS. 3 to 6, when the MENU / OK switch 17 is pressed, the value set at that time is stored as a set value in the storage means (ROM 108 or the like). It should be noted that the setting value need only be reset only when the photographer determines that it needs to be changed, as will be described later, and does not need to be set every time shooting is performed.

  In this way, the “shooting trigger focus evaluation value” can be arbitrarily set by the setting means. For example, “I want to take an image that is accurately focused on the subject”, “I want to take a slightly focused image”, etc. Shooting according to the needs of the photographer can be performed.

4). Imaging Operation Next, an imaging operation by the imaging unit and the control unit included in the imaging apparatus of the present invention will be described with reference to FIGS.

  First, a mode in which shooting is performed with a fixed focal length by operating the MENU / OK switch 17, the left / image confirmation switch 18, the down / macro switch 19, the up / strobe switch 20, and the right switch 21 (hereinafter referred to as “shooting”) (Focus fixed automatic shooting), and the focal length for shooting is fixed.

  Further, by operating each of the above switches, a fixed focus automatic photographing standby screen (hereinafter also referred to as a standby screen) as shown in FIG. 7A is displayed on the display means.

  A focus evaluation value determination frame 30 for specifying a focus evaluation value determination area for calculating a focus evaluation value is displayed in the center of the standby screen shown in FIG. Here, the focus evaluation value acquisition unit configured by the processor 104 or the like continuously calculates the focus evaluation value based on the image data in the focus evaluation value determination area specified by the focus evaluation value determination frame 30. is there.

  Further, the position and size of the focus evaluation value determination frame 30 can be arbitrarily changed by operating the left / image confirmation switch 18, the lower / macro switch 19, the upper / strobe switch 20, and the right switch 21. Can do. In this way, the optimum focus evaluation value determination frame 30 can be set according to the position and size of the subject in the screen, and shooting suitable for various shooting needs and various shooting environments of the photographer. It can be performed.

  Further, on the left side of the standby screen, the “shooting trigger focus evaluation value” (“threshold” in FIG. 7A) set on the focus fixed automatic shooting setting screen (FIG. 6) and the focus in the focus evaluation value determination frame 30 are displayed. A vertical bar 31 is displayed in which the evaluation value (“current focus evaluation value” in FIG. 7A, hereinafter referred to as the current focus evaluation value) is indicated by an arrow.

  In the upper right of the standby screen, the “continuous shooting number” set on the fixed focus automatic shooting setting screen (FIG. 3) and the number of automatic shootings so far (automatic shooting number / continuous shooting number) are displayed. In the lower right of the screen, a display indicating that the camera is currently waiting for automatic shooting (“standby” in FIG. 7A) is displayed.

  In the case of “standby” as shown in FIG. 7A, the photographing operation by the imaging unit is not performed even if the current focus evaluation value exceeds the “shooting trigger focus evaluation value”. In this state, for example, when the camera is fixed on a tripod as required, or when the preparation for shooting is completed by holding it in hand and the release button 2 is pressed, the focus fixing automatic shown in FIG. A photographing monitoring screen (hereinafter also referred to as a monitoring screen) is displayed on the display means. In the monitoring screen, the display at the lower right of the screen is “monitoring”, and the monitor waits for the current focus evaluation value to exceed the “shooting trigger focus evaluation value”.

  For example, as shown in FIG. 8A, when a digital camera 33 is fixed to a tripod 32 and a subject flower 34 is photographed at a fixed focal length, the subject flower 34 is blown by the wind and the focus is increased. The wind stops from the state of mismatch (FIG. 8A), and the distance between the digital camera 33 and the subject flower 34 matches the fixed focal length as shown in FIG. When the value exceeds the “shooting trigger focus evaluation value”, shooting is performed as shown in FIG. FIG. 7C shows a fixed focus automatic shooting shooting screen (hereinafter also referred to as shooting screen).

  Here, the imaging operation is performed by the control unit configured by the processor 104 or the like, and the “shooting trigger focus evaluation value” set by the setting unit and the current focus calculated continuously by the focus evaluation value acquisition unit. Comparison with the evaluation value is performed, and when the current focus evaluation value exceeds the “shooting trigger focus evaluation value”, control is performed so that the imaging unit performs shooting.

  In this embodiment, shooting is performed when the current focus evaluation value exceeds the “shooting trigger focus evaluation value”. However, the current focus evaluation value is set in advance with respect to the “shooting trigger focus evaluation value”. When the value falls within the predetermined range, it may be controlled to take a picture. In addition, a threshold can be set for the time (number of frames) when the current focus evaluation value exceeds the “shooting trigger focus evaluation value”, and the current focus evaluation value exceeds the “shooting trigger focus evaluation value” for a certain period of time. It may be controlled to take a picture only when it is present.

  When shooting is performed, the number of shots at the upper right of the screen increases as shown in FIG. In other words, the number of shots is counted by the control means, and the standby screen is displayed if shooting is performed up to the “number of continuous shots”, and the monitoring screen is displayed if shooting is not completed up to “number of shots”. Is done.

  In addition, even when the current focus evaluation value exceeds the “shooting trigger focus evaluation value” from the monitoring state shown in FIG. 7B, the time set as “interval” has elapsed since the last automatic shooting. If not, maintain monitoring status. In addition, even when the focus evaluation value acquired when the time set as the “interval” has elapsed since the last automatic shooting does not exceed the “shooting trigger focus evaluation value”, the monitoring state is maintained and the focus is refocused. Wait for.

  If the release button 2 is pressed while the monitoring screen is displayed, automatic shooting is interrupted and the screen returns to the standby screen. In addition, when the standby screen is displayed, the fixed focus automatic photographing is terminated by operating the MENU / OK switch 17, the left / image confirmation switch 18, the lower / macro switch 19, the upper / strobe switch 20, and the right switch 21. .

5). Second Embodiment It is also preferable that the setting unit sets the peak value of the focus evaluation value in the monitoring state as the “shooting trigger focus evaluation value”. Hereinafter, an embodiment in which “imaging trigger focus evaluation value” is set in a monitoring state will be described with reference to FIGS. 9 to 10. Note that a description of the same points as in the above embodiment will be omitted.

  First, fixed focus automatic photographing as shown in FIG. 9A is performed by operating the MENU / OK switch 17, the left / image confirmation switch 18, the lower / macro switch 19, the upper / strobe switch 20, and the right switch 21. A threshold setting screen (hereinafter also referred to as a threshold setting screen) is displayed on the display means. Similar to the above-described fixed focus automatic photographing standby screen and the like, on the threshold setting screen, the position and size of the focus evaluation value determination frame 30 can be arbitrarily changed by operating each switch.

  On the left side of the threshold setting screen, the maximum focus evaluation value (“peak” in FIG. 9A) calculated after the transition to the threshold setting screen and the current focus evaluation value (in FIG. 9A) are displayed. The “current focus evaluation value”) and the vertical bar 31 indicated by arrows are displayed. A monitoring image is displayed in the background of the threshold setting screen.

  Here, the photographer 35 confirms the monitoring image of the camera 33 and gradually brings the camera 33 closer to the subject 34 while maintaining the state where the lens of the camera 33 is directed toward the subject 34 (FIG. 10A). ), (B)) and as shown in FIG. 10B, the focus evaluation value becomes the maximum value (peak) when the distance between the subject and the camera coincides with the fixed focal length (FIG. 9B). ).

  If the camera 33 is further moved closer to the subject 34 from this state (FIG. 10C), the current focus evaluation value is decreased again as shown in FIG. 9C. Here, the storage means temporarily stores the focus evaluation value acquired by the focus evaluation value acquisition means during the monitoring image display, and stores the maximum value as the peak value of the focus evaluation value. In this embodiment, the case of approaching from a position slightly away from the fixed focal length has been described as an example, but the same applies to the case of moving away from a position slightly closer than the fixed focal length.

  In this state, when the MENU / OK switch 17, the left / image confirmation switch 18, the lower / macro switch 19, the upper / strobe switch 20, and the right switch 21 are used to complete the threshold setting screen, the setting unit stores the storage unit. The peak value of the focus evaluation value stored in is set as the “shooting trigger focus evaluation value”.

  In this way, not only when shooting with the imaging means fixed, but also when the photographer holds the camera and approaches the subject moderately or moves away from the subject moderately, the focus evaluation value The peak value can be easily set, and automatic shooting can be performed at the moment of focusing.

6). Third Embodiment Furthermore, the imaging apparatus of the present invention preferably includes a correction unit. Hereinafter, the correction means will be described with reference to FIG. The correction means is configured by the processor 104 or the like, determines the brightness of the outside world, and corrects the value of the “shooting trigger focus evaluation value” according to the brightness. Note that a description of the same points as in the above embodiment will be omitted.

  Here, it is known that the focus evaluation value changes depending on the brightness of the outside world even if the distance between the imaging unit and the subject is the same. For example, as shown in FIG. 11, when the relationship between the focus evaluation value and the distance to the subject is graphed, the distance to the subject at which the peak of the focus evaluation value comes does not change, but the focus increases as the brightness of the outside world becomes darker. The peak evaluation value decreases.

  For example, even if the “shooting trigger focus evaluation value” is set in an environment where the outside world is moderately bright (in the case of FIG. 11A) and appropriate automatic shooting is performed, the outside world becomes dark (FIG. 11B, In the case of (C), automatic shooting is not performed with the set value as it is.

  Therefore, the photographer needs to set the “shooting trigger focus evaluation value” again by the above-described means according to the brightness of the outside world at the time of shooting. However, every time the shooting environment changes, the “shooting trigger focus evaluation value” It is cumbersome to perform the setting.

  Therefore, in the present embodiment, the correction unit multiplies the “shooting trigger focus evaluation value” stored in the storage unit by the control program recorded in the ROM 108 by a coefficient corresponding to the luminance in the focus evaluation value determination area. By performing the correction process, automatic shooting according to fluctuations in the brightness of the outside world is possible. By performing such correction processing, in many cases, the photographer can save the trouble of setting the “shooting trigger focus evaluation value” again and improve the usability of the digital camera.

  Note that the method for setting the “shooting trigger focus evaluation value” is not limited to the above example. For example, a plurality of “shooting trigger focus evaluation values” are set, and an optimal value is appropriately set according to the shooting environment or the like. May be selectable. Alternatively, the “shooting trigger focus evaluation value” may be stored as a fixed value, and correction may be performed according to the shooting environment by the correction unit. Further, the peak value at the time of past photographing may be set as the “photographing trigger focus evaluation value”.

  As described above, according to the present invention, in a mode in which shooting is performed with a fixed focal length, manual shooting is performed by automatically determining that focus has been achieved at a preset position on the screen, and thus performing manual shooting. It is possible to eliminate a time lag that occurs in shooting and to easily shoot a good image in which the subject is in focus. Furthermore, the present invention can be realized with a simple configuration, and can be realized inexpensively and easily.

  Therefore, for example, in fixed-point observation that captures the moment when an animal, insect, etc. approaches the imaging means, it is more efficient than the interval photography that is generally performed, and only when the animal, insect, etc. approaches the camera. can do. The present invention can also be applied to security cameras and the like.

  In the present invention, since the “shooting trigger focus evaluation value” and the current focus evaluation value are displayed on the display unit, the photographer can predict to some extent the timing at which the shooting operation is performed. Further, as described above, when the photographer holds the camera and approaches or moves away from the subject, the photographer moves while visually recognizing the “shooting trigger focus evaluation value” displayed on the display unit and the current focus evaluation value. Can support the photographer.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

It is an example of the external view of the imaging device (digital camera) which concerns on this invention, Comprising: (a) is a camera top view, (b) is a camera front view, (c) shows a camera back view. It is an example of the block diagram which shows the control system of a digital camera. It is an example of a fixed focus automatic imaging | photography setting screen, Comprising: A mode that the number of continuous imaging | photography is set is shown. It is an example of a fixed focus automatic imaging | photography setting screen, Comprising: A mode that an interval (minute) is set is shown. It is an example of a fixed focus automatic imaging | photography setting screen, Comprising: A mode that an interval (second) is set is shown. It is an example of a focus fixed automatic imaging | photography setting screen, Comprising: A mode that an imaging | photography trigger focus evaluation value is set is shown. It is an example of a display screen at the time of fixed focus automatic photographing, (a) shows a standby screen, (b) shows a monitoring screen, and (c) shows a screen during photographing. It is a schematic diagram which shows a mode that the subject is image | photographed by focus fixed automatic imaging | photography, (a) is a mode that the subject is blown in the wind, (b) has shown the mode in the windless state. It is an example of a fixed focus automatic photographing threshold setting screen, where (a) is far from a fixed focal length, (b) is a fixed focal length, and (c) is closer to a fixed focal length. Indicates. It is a schematic diagram which shows the relationship between an imaging means and a to-be-photographed object, Comprising: When (a) is separated from the fixed focal distance, (b) is a fixed focal distance, (c) is from a fixed focal distance. The near case is shown. It is an example of the schematic diagram which shows the graph which shows the relationship between the brightness of an external field, and a focus evaluation value, and the mode of the external field.

Explanation of symbols

1 Sub LCD
2 Release button 3 Flash emission unit 4 Mode dial 5 Distance measuring unit 6 Remote control light receiving unit 7 Lens barrel unit 8 AFLED
9 Strobe LED
10 LCD monitor 11 Optical viewfinder 12 Zoom button TELE
13 Power switch 14 Zoom button WIDE
15 Playback switch 16 Self-timer / delete switch 17 MENU / OK switch 18 Left / image confirmation switch 19 Lower / macro switch 20 Up / strobe switch 21 Right switch 22 Display switch 30 Focus evaluation value determination frame 31 Vertical bar 121 Memory card throttle

Claims (9)

Imaging means for acquiring an image based on a light image relating to a subject;
Display means for displaying an image acquired by the imaging means;
Setting means for setting a focus evaluation value that triggers photographing by the imaging means;
A focus evaluation value acquisition unit that acquires a current focus evaluation value during display of the monitoring image acquired by the imaging unit and displayed on the display unit;
When shooting with a fixed focal length, the difference between the current focus evaluation value acquired by the focus evaluation value acquisition unit and the focus evaluation value set by the setting unit is within a predetermined range. And a control means for controlling the imaging means to perform photographing.   The imaging apparatus according to claim 1, wherein the focus evaluation value acquisition unit acquires the current focus evaluation value based on data in a focus evaluation value determination area set in the display unit. A correction unit that corrects the focus evaluation value set by the setting unit based on luminance in the focus evaluation value determination area;
The control means controls the imaging means to perform photographing when a difference between the current focus evaluation value and the focus evaluation value corrected by the correction means falls within a predetermined range. 2. The imaging device according to 2. A storage means for storing a peak value of the focus evaluation values acquired by the focus evaluation value acquisition means during display of the monitoring image;
The imaging apparatus according to claim 1, wherein the setting unit sets a peak value stored in the storage unit as the focus evaluation value.   The imaging apparatus according to claim 2, wherein the focus evaluation value determination area can be set at an arbitrary size at an arbitrary position of the display unit.   The imaging apparatus according to claim 1, wherein the setting unit sets a plurality of the focus evaluation values.   The imaging apparatus according to claim 1, wherein the setting unit sets a threshold at a time when the current focus evaluation value exceeds a focus evaluation value serving as a trigger for the photographing. .   The image pickup apparatus according to claim 1, wherein the setting unit sets an upper limit value of the number of shots when performing continuous shooting.   The imaging apparatus according to any one of claims 1 to 8, wherein the setting unit sets a time interval from the end of one shooting to the start of shooting again.