JP2008046620A - Image capture device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single lens reflex digital camera that can find a focus as intended by the shooter even when electronic zoom is on. <P>SOLUTION: The image capture device includes: a movable mirror to be entered into, and removed from, an optical path; an imaging element 11 for shooting an object image and generating an image signal; a signal processor for zooming in on, or out of, the image based on the image signal and generating a processed image signal; a focus sensor for sensing a focusing signal, representing a focusing state of a part of the object image, based on the image signal; a display device for presenting the image based on the image signal; and a controller for controlling the generation of a focus frame to be displayed on the display device. The focus frame is displayed at a location on the image associated with that part of the object image to indicate where the focus sensor should detect the focusing state. The controller changes display of the focus frame according to whether or not zooming or zoom-out processing is performed by the signal processor on the image and displays the focus frame on the display device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to a digital camera. More specifically, the present invention relates to a single-lens reflex type digital camera having a photographing mode for sequentially processing image signals output from an image sensor and sequentially displaying visible images corresponding to the image signals on a display device. .

  In recent years, many single-lens reflex type digital cameras having an imaging element such as a charge coupled device (CCD) image sensor and a complementary metal-oxide semiconductor (CMOS) image sensor have been proposed and sold.

  A single-lens reflex digital camera includes a movable mirror (quick return mirror) that switches a position where an optical image is formed to a first position and a second position that are different from each other. Such a digital camera receives an optical image formed at the first position at the time of imaging by an imaging device, converts it into an electrical image signal, and outputs it. On the other hand, when determining the composition before imaging, the digital camera forms the optical image formed at the second position on the focusing screen of the viewfinder. The image is guided to the photographer's pupil through the observation imaging lens system.

  Similar to compact digital cameras, products with various functions have been proposed for single-lens reflex digital cameras. For example, Patent Document 1 proposes an electronic camera device having an optical zoom function and an electronic zoom function. The optical zoom function is a function for enlarging / reducing a subject by using a magnification function of the imaging lens system. The electronic zoom function is a function for enlarging / reducing a subject by cutting out and recording a part of an image signal output from an image sensor. The device of Patent Document 1 can change the apparent focal length change range widely by combining both zoom functions.

There are also various functions that are executed during the focusing operation, so-called autofocus operation. For example, the above-described electronic camera device detects an image signal output from the image sensor with an autofocus (AF) sensor. Then, the AF frame is usually displayed on both the optical viewfinder and the display monitor so that it can be easily understood which subject on the shooting screen is in focus. This “AF frame” is displayed superimposed on the subject image in correspondence with the position where the AF sensor is arranged. The photographer aligns the AF frame with the position of the subject to be focused displayed on the optical viewfinder or display monitor. As a result, the AF sensor detects the signal at the position, and photographing with the desired position can be performed.
JP 2004-72206 A

  The AF sensor is usually arranged so as to detect an optical signal incident on a predetermined position on the image sensor. The AF sensor detects a change in the high-frequency component of the image signal at the position, and feeds back a signal for focusing to the autofocus control mechanism.

  When the lens has a zoom function, when the electronic camera device records an image captured by all the effective pixels on the image sensor or displays it on the monitor, the optical function can be used even if the zoom function is operated. On the viewfinder and the display monitor, an image captured by all the effective pixels on the image sensor (an image interlocked with the zoom magnification) is displayed. Therefore, there is no deviation between the AF frame display position and the position where the AF sensor is actually arranged.

  However, when the electronic camera device records an image captured by a part of the effective pixels on the image sensor or displays it on the monitor, the AF frame display position is shifted from the position where the AF sensor is actually arranged. Will occur. The reason is that the image captured in the partial area is enlarged so that it is the same size as the image captured in the entire effective pixel and displayed on the optical viewfinder and the display monitor, but the AF frame is displayed. This is because the change in size was not considered. As a result, it has been difficult for the photographer to determine whether or not the position intended by the photographer is accurately focused. Note that an aspect of recording an image captured in a partial area of the image sensor corresponds to a time when the electronic zoom function is turned on or a time of shooting in which the number of recording pixels is changed.

  An object of the present invention is to realize a digital camera capable of ensuring a focusing operation intended by a photographer even when using an electronic zoom or photographing with a changed number of recording pixels in a single-lens reflex type digital camera. It is.

  The imaging device according to the present invention is detachably connected to the imaging lens device. The imaging lens device has an imaging lens system that forms a subject image. The imaging device is disposed at the first position, the movable mirror capable of switching a position where the subject image is formed to one of a first position and a second position by being inserted into and extracted from the optical path, and the subject An image sensor that captures an image to generate an image signal, a signal processing unit that performs an image enlargement process or a reduction process based on the image signal, and generates a processed image signal; and the subject at the second position A focus sensor that detects a focus signal indicating a focus state of a part of the subject image based on the subject image when the image is formed; and a display device that displays an image based on the image signal; And a control unit for controlling generation of a focus frame to be further displayed on the display device. The focus frame is displayed at a position on the image corresponding to a part of the subject image and indicates a position where the focus sensor detects an in-focus state, and the control unit is configured to display the image in the signal processing unit. The display of the focus frame is changed and displayed on the display device in accordance with the enlargement process or the reduction process.

  The control unit may change the size of the focus frame according to an enlargement rate or reduction rate of the image in the signal processing unit and display the change on the display device.

  There are a plurality of the focus frames, and the control unit may change the distance between the focus frames according to the enlargement rate or reduction rate of the image in the signal processing unit and display the change on the display device. Good.

  The control unit further includes a memory that holds data indicating a plurality of display modes of the focus frame in correspondence with an enlargement rate or a reduction rate of the image in the signal processing unit, and the control unit includes the signal processing The memory is referred to according to the enlargement ratio or reduction ratio of the image in the section, one of the data indicating the plurality of display modes is read, and the size of the focus frame is changed based on the read data. You may display on a display apparatus.

  The memory may hold data indicating a plurality of display modes having different display positions and enlargement ratios of the focus frame in correspondence with the enlargement ratio or reduction ratio of the image in the signal processing unit.

  According to the present invention, it is possible to provide a digital camera capable of realizing a focusing operation intended by a photographer even when using an electronic zoom or photographing with a changed number of recorded pixels in a single-lens reflex type digital camera.

  Hereinafter, embodiments of a digital camera according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows the configuration of the digital camera according to the present embodiment. The digital camera is a single-lens reflex camera, and includes a camera body 1 and an imaging lens device 2. The imaging lens device 2 has a lens mount 21 and is detachably attached to a body mount 23 provided on the front surface of the digital camera 1.

  The digital camera 1 includes various optical or electrical elements. Hereinafter, the components of the digital camera 1 will be described together with the operation of the digital camera 1 during imaging.

  The subject light that has passed through the imaging lens device 2 reaches the quick return mirror 4. The quick return mirror 4 is arranged so that it can be inserted into and removed from the optical path. The subject light is split into two light beams by the main mirror 4 a of the quick return mirror 4, and the reflected light beam is guided to the finder optical system 19. On the other hand, the transmitted light beam is reflected by the sub-mirror 4 b provided on the back side of the quick return mirror 4 and used as the AF light beam of the focus detection unit 5. The focus detection unit 5 uses a phase difference detection method.

  The light beam reflected by the main mirror 4 a forms an image on the finder screen 6. The subject image formed on the finder screen 6 can be observed from the finder eyepiece window 9 via the pentaprism 7 and the eyepiece lens 8. The finder screen 6 is arranged at a position of the imaging lens system where an optical image is formed.

  The camera body 1 has two shooting modes. The first is a normal shooting mode in which a photographer or the like takes a picture while observing the viewfinder eyepiece window 9, and is a normal shooting mode in a conventional single-lens reflex camera.

  FIG. 2 shows an optical path in the camera body 1 in the normal photographing mode. In the normal shooting mode, since the quick return mirror 4 is disposed at a predetermined position on the optical path X, the photographer can observe the subject image from the viewfinder eyepiece window 9. At the time of actual photographing, the quick return mirror 4 is flipped up out of the optical path X, and the shutter unit 10 is opened to form a subject image on the imaging surface of the image sensor 11. Note that the image sensor 11 is disposed at a position where an optical image of the imaging lens system L is formed.

  On the other hand, the second shooting mode is a shooting mode (hereinafter referred to as a live view mode) in which image signals output from the image sensor are sequentially processed, and visible images corresponding to the image signals are sequentially displayed on the display device. FIG. 3 shows an optical path in the camera body 1 in the live view mode. In the live view mode, the quick return mirror 4 is retracted from the optical path X. Therefore, an image of the subject, a so-called through image, is displayed on the display monitor 16 such as a liquid crystal monitor via the image sensor 11.

  Refer to FIG. 1 again. A body microcomputer 12 for controlling various sequences is mounted in the camera body 1. The image sensor control unit 13 performs drive control of the image sensor 11. The shutter control unit 14 performs drive control of the shutter unit 10. The image display control unit 15 for image display reads an image signal from the image sensor 11 and controls to display a captured image on the display monitor 16 after predetermined image processing. In addition, the image recording control unit 17 reads and writes captured image data from and to a recording medium such as an SD card (registered trademark) (not shown) via the image reading / recording unit 18. In the following description, it is described as “recording an image” for convenience.

  The detachable imaging lens device 2 has an imaging lens system L for connecting a subject image to the imaging device 11 in the camera body 1. A lens microcomputer 20 that controls various sequences in the imaging lens device 2 and incorporates various lens information is mounted. A focus control unit 26 that drives and controls the focus lens group 25 is mounted in the imaging lens device 2. Further, an aperture control unit 27 that controls the aperture unit 28 is mounted.

  The camera body 1 and the imaging lens device 2 are respectively provided with an electrical section 22 (not shown) of the lens mount 21 on the imaging lens apparatus 2 side and an electrical section 24 of the body mount 23 on the camera body 1 side. Various control signals are exchanged via a not shown).

  FIG. 4 is a top view of the camera body 1 to which the imaging lens device 2 according to the present embodiment is attached.

  The camera body 1 is a housing that is supported by a photographer or the like when photographing a subject. The camera body 1 includes a shutter button 30 and a shutter speed setting dial 31. The shutter button 30 and the shutter speed setting dial 31 are provided on the right side of the upper surface of the camera body 1.

  The shutter speed setting dial 31 is an operation member that sets the shutter speed by rotating. The shutter speed setting dial 31 has an auto position where the shutter speed is automatically set.

  The camera body 1 includes a display monitor 16. The display monitor 16 is provided on the surface of the camera body 1 on the photographer side or the like. The operation of the display monitor 16 will be described later.

  The imaging lens device 2 has a filter mount 37 on the side closest to the subject. The imaging lens device 2 includes a zoom ring 38, a focus ring 39, and an aperture ring 40 in order from the filter mount 37 toward the camera body 1 (in the negative direction of the Z axis). The zoom ring 38, the focus ring 39, and the aperture ring 40 are all cylindrical rotation operation members and are rotatably disposed on the outer peripheral surface of the imaging lens device 2.

  FIG. 5 is a rear view of the camera body 1 according to the present embodiment. The camera body 1 includes a power button 70, a shooting / playback mode switching lever 71, a MENU button 72, a cross operation key 73, a SET button 74, a narrowing mode button 76, a function button (1) 77, and a function button (2) 78. including.

  The power button 70 is an operation member for turning on / off the power of the camera body 1. The shooting / playback mode switching lever 71 is an operation member that switches between the shooting mode and the playback mode by switching the lever. Here, the shooting mode is a mode that is set in the camera body 1 in order to newly shoot a subject image into an image signal. The playback mode is a mode that is set in the camera body 1 to display an image signal that has already been taken and stored.

  The MENU button 72 is an operation member for causing the display monitor 16 to display various operation menus. The cross operation key 73 has up, down, left and right arrow keys and is an operation member for selecting display items of various operation menus. The SET button 74 is an operation member for confirming display items of various operation menus. The narrow-down mode button 76 shifts to a narrow-down mode to be described later by pressing this button. The function button (1) 77 and the function button (2) 78 are assigned frequently used shooting / playback menus.

  The digital camera according to the present embodiment has an electronic zoom function for enlarging / reducing a subject image by image processing. The electronic zoom function can be divided into two shooting modes, specifically, an EX optical zoom mode and a digital zoom mode, depending on the difference in image processing. The EX optical zoom mode is a mode in which the number of pixels of the recorded image is kept constant regardless of the zoom magnification. The digital zoom mode is a mode in which the number of pixels of an image to be cut out decreases as the zoom magnification increases, and the recorded or displayed image becomes coarse.

  6A and 6B show display examples on the display monitor 16 when the digital zoom mode and the EX optical zoom mode are turned on or off, respectively.

  FIG. 6A shows a case where the live view mode is set as the shooting mode. When the live view mode is set, both the EX optical zoom and the digital zoom can be selected. In this example, each icon can be designated using the cross operation key 73 and the setting can be performed by pressing the SET button 74.

  FIG. 6B shows a case where the normal shooting mode is set as the shooting mode. When the normal shooting mode is set as the shooting mode, neither the EX optical zoom nor the digital zoom can be selected. In this example, even if each icon is specified using the cross operation key 73, the icon cannot be selected, and the acceptance of the setting of each mode is prohibited. In this way, by prohibiting the use of the electronic zoom in the normal shooting mode, the composition can be easily determined even using the optical viewfinder, and the digital camera is easy to use for the photographer.

  Even when the live view mode is set as the shooting mode, any setting of electronic zoom is not accepted if L (maximum) is set as the number of recording pixels. When setting the electronic zoom mode, S (minimum) or M (normal) is selected as the number of recording pixels. By making such a selection, it is possible to accept the setting of the electronic zoom.

  Hereinafter, the EX optical zoom mode and the digital zoom mode will be described in detail with reference to FIGS.

  FIGS. 7A to 7C show image processing in the EX optical zoom mode. As an example, the imaging device has a maximum recording pixel number of 7,400,000 pixels, and the number of pixels of an image recorded in the EX optical zoom mode is 3 million pixels (constant value).

  FIG. 7A shows image processing when the electronic zoom mode is not set by the user (when the zoom magnification is set to 1.0). At this time, image data is generated using the total number of pixels (7.4 million pixels) of the image sensor. Thereafter, the image of 7.4 million pixels is reduced as a whole, converted into image data of 3 million pixels, and recorded. As for the image displayed on the display monitor 16, the image data of 7.4 million pixels is reduced as a whole and displayed on the display monitor 16 of 640,000 pixels, for example.

  FIG. 7B shows image processing when the zoom magnification is set to 1.2 times by the user. At this time, an image of 5 million pixels inside is extracted from the total number of pixels (7.4 million pixels) of the image sensor. The clipped image is reduced, converted into image data of 3 million pixels, and recorded. An image displayed on the display monitor 16 is generated by reducing a 3 million pixel image to be recorded.

  When the image of FIG. 7A displayed on the display monitor 16 is compared with the image of FIG. 7B, the angle of view of the image of FIG. 7B is the angle of view of the image of FIG. Narrower than. Therefore, when these images are displayed on the display monitor 16 of the same size, the image in FIG. 7B is displayed as an enlarged version of the image in FIG.

  FIG. 7C shows image processing when the zoom magnification is set to 1.5 times by the user. At this time, of the total number of pixels of the image sensor (7.4 million pixels), an image shot with 3 million pixels inside is cut out. Since the number of pixels of the cut out image is the same as the number of recording pixels, the image is recorded as it is. An image displayed on the display monitor 16 is generated by reducing a 3 million pixel image to be recorded. The displayed image is obtained by further enlarging the image displayed on the display monitor 16 in the example of FIG.

  In addition, the numerical value of a magnification is an example. The same applies to the following description.

  FIGS. 8A to 8C are schematic diagrams for explaining the principle when the EX optical zoom mode is used together with the zoom function of the lens. As in the previous example, it is assumed that the image sensor has a maximum number of recorded pixels of 7.4 million pixels. The focal length of the imaging lens system is assumed to be 14 mm to 50 mm.

  FIG. 8A shows a state where the electronic zoom mode is not set. In this case, image processing for reducing the number of pixels, such as interpolation processing, is performed on the captured image data. As a result, the number of pixels of the image data is a predetermined number of pixels smaller than the maximum number of recorded pixels at all magnifications of optical zoom (14 mm to 50 mm). For example, image data of 7.4 million pixels is converted into image data equivalent to 3 million pixels.

  FIG. 8B shows a state in which an electronic zoom mode corresponding to 5 million pixels is set with a magnification of 1.2. In this case, the center part corresponding to 5 million pixels is cut out from the area corresponding to 7.4 million pixels of the image sensor, and then converted into image data corresponding to 3 million pixels. For this reason, when optical zoom is performed using the same imaging lens system, the focal length is shifted to 1.2 times, and the angle of view corresponding to the focal length of 16.8 mm to 60 mm changes. In other words, when optical zoom is performed using the same imaging lens system, the change in the angle of view of the optical zoom is narrowed without deteriorating the number of recording pixels (with the number of recording pixels being 3 million pixels). Can be migrated.

  FIG. 8C shows a state in which the electronic zoom mode corresponding to 3 million pixels is set with the magnification specified as 1.5 times. In this case, in the region corresponding to 7.4 million pixels that the image sensor has, the center portion corresponding to 3 million pixels is cut out and photographing is performed. For this reason, when optical zoom is performed using the same imaging lens system, the focal length is shifted to 1.5 times, and the angle of view corresponding to the focal length of 21 mm to 75 mm changes. Similarly, when optical zoom is performed using the same imaging lens system, the change in the angle of view of the optical zoom can be shifted to the narrow side without degrading the number of recording pixels.

  FIGS. 9A to 9C show image processing in the digital zoom mode. It is assumed that the image sensor has a maximum recording pixel number of 7.4 million pixels.

  FIG. 9A shows image processing when the electronic zoom mode is not set by the user (when the zoom magnification is set to 1.0). The process at this time is the same as the image process in the EX optical zoom mode shown in FIG. That is, image data is generated using the total number of pixels (7.4 million pixels) of the image sensor, and then the image of 7,400,000 pixels is reduced overall, converted to image data of 3 million pixels, and recorded. . As for the image displayed on the display monitor 16, the image data of 7.4 million pixels is reduced as a whole and displayed on the display monitor 16 of 640,000 pixels, for example.

  FIG. 9B shows image processing when the zoom magnification is set to 1.2 by the user. At this time, an image of 5 million pixels inside is extracted from the total number of pixels (7.4 million pixels) of the image sensor. The cut out image is recorded as it is. As for the image displayed on the display monitor 16, the cut out image of 5 million pixels is reduced as a whole and displayed on the display monitor 16.

  When comparing the image of FIG. 9A displayed on the display monitor 16 with the image of FIG. 9B, the angle of view of the image of FIG. 9B is the angle of view of the image of FIG. 9A. Narrower than. When these images are displayed on the display monitor 16 having the same size, the image in FIG. 9B is displayed as an enlarged version of the image in FIG.

  Regarding the quality of the image displayed on the display monitor 16, the image of FIG. 9B is coarser than the image of FIG. 9A. The reason is that the image displayed on the display monitor 16 is generated based on an image of 7.4 million pixels in FIG. 9A, whereas it is based on an image of 5 million pixels in FIG. 9B. This is because it is generated.

  FIG. 9C shows image processing when the zoom magnification is set to 1.5 times by the user. At this time, an image of 3 million pixels inside is cut out from the total number of pixels (7.4 million pixels) of the image sensor. The cut out image is recorded as it is. As for the image displayed on the display monitor 16, the cut out image of 3 million pixels is reduced as a whole and displayed on the display monitor 16. The displayed image is obtained by further enlarging the image displayed on the display monitor 16 in the example of FIG. As for the quality of the image displayed on the display monitor 16, the image shown in FIG. 9C is further coarser than the image shown in FIG. 9B for the same reason as described above.

  FIGS. 10A to 10C are schematic diagrams illustrating the principle when the digital zoom mode is used together with the zoom function of the lens. As in the previous example, it is assumed that the image sensor has a maximum number of recorded pixels of 7.4 million pixels. The focal length of the imaging lens system is assumed to be 14 mm to 50 mm.

  FIG. 10A shows a state where the digital zoom mode is not set. In this case, the angle of view changes in a range corresponding to a focal length of 14 mm to 50 mm.

  FIG. 10B shows a state where a digital zoom mode equivalent to 2 × is set. In this case, the center portion corresponding to 2 times is cut off and photographing is performed. For this reason, when optical zoom is performed using the same imaging lens system, the focal length is shifted to twice, and the angle of view corresponding to a focal length of 28 mm to 100 mm changes.

  FIG. 10C shows a state where a digital zoom mode equivalent to 4 times is set. In this case, the center portion corresponding to 4 times is cut off and photographing is performed. For this reason, when optical zoom is performed using the same imaging lens system, the focal length is shifted to 4 times, and the angle of view corresponding to the focal length of 56 mm to 200 mm changes.

  As understood from the above description, the digital zoom mode can greatly change the angle of view.

  The above-described EX optical zoom mode and digital zoom mode may be used in combination. By using in combination, the angle of view can be changed more greatly. For example, when the EX optical zoom mode corresponding to 3 million pixels and the 4 × digital zoom mode are used in combination, if the imaging lens system described above has a focal length of 14 mm to 50 mm, the angle of view corresponds to a focal length of 84 mm to 300 mm. Can be changed.

  Next, details of a screen displayed on the display monitor 16 in the EX optical zoom mode and the digital zoom mode will be described with reference to FIGS.

  An AF frame is drawn on the display monitor 16 so as to be superimposed on the subject image before photographing. FIG. 11 shows an example of AF frames A and B displayed on the display monitor 16.

  At a position corresponding to the AF frame A to be displayed, an AF sensor that detects a change in the high-frequency component in the horizontal direction of the image signal output from the image sensor at that position is disposed. In addition, an AF sensor that detects a change in the high-frequency component in the vertical direction of the image signal output from the image sensor at that position is disposed at a position corresponding to the AF frame B, and performs an AF operation.

  When the electronic zoom is not set, that is, when the magnification is set to 1.0, the AF frame and the AF sensor arrangement position coincide with each other over the entire zoom area, and an accurate AF operation is performed. . Note that “electronic zoom” means one or both of the EX optical zoom mode and the digital zoom mode. The same applies to the following description.

  FIG. 12 shows an example in which AF frames 122 to 124 are displayed superimposed on the subject image. Here, a composition in which the utility pole 127 is included in front of the two persons 125 and 126 is taken as an example.

  First, when the user has not set the electronic zoom, the normal photographing frame 120 is displayed. Next, when the user sets the electronic zoom, a shooting mode using a part of the image sensor is set, and the electronic zoom frame 121 is displayed on the entire display monitor.

  FIG. 13 shows the relationship between the electronic zoom frame 121 and the subject image. The subject image is enlarged and displayed according to the magnification of the electronic zoom. On the other hand, FIG. 13 also shows an example in which the AF frames 122 to 124 indicated by solid lines are displayed at the same positions as those shown in FIG. The AF frames 122 to 124 are displayed in OSD (On Screen Display) so as to be superimposed on the images of the persons A and B.

  However, considering that the subject image is enlarged by electronic zoom, the actual AF sensor is present at positions 130 to 132 indicated by broken lines, and an image signal output from the image sensor at that position is detected. is doing. Therefore, when the AF frames 122 to 124 are displayed, the user misunderstands that the persons A and B are in focus. Actually, it is operated to focus on the person A and the utility pole, but the signal for focusing on the person B is not detected. Further, in general, in the focusing operation of the camera, control is generally performed so that the object in front of the subject is preferentially focused. In this example, the person A or B is in focus. Focuses only on the utility pole without being burned. Therefore, the focusing operation intended by the photographer is not guaranteed.

  In order to ensure accurate focusing even when such an electronic zoom is set, it is necessary to display each AF frame on the display monitor in accordance with the magnification of the electronic zoom. Specifically, it is necessary to change the display position of each AF frame (or the interval between the AF frames) and the size in a similar manner according to the magnification of the electronic zoom.

  FIG. 14 shows AF frames 130 to 132 indicated by broken lines in the example of FIG. Since the display position and size of each AF frame are changed according to the magnification of the electronic zoom, the user can reliably grasp the position of the AF sensor by referring to the AF frames 130 to 132. Therefore, it is possible to focus on the subject intended by the user.

  Note that the frame data processing for displaying the above-described AF frames 130 to 132 on the display monitor is realized by, for example, the body microcomputer 12. The body microcomputer 12 changes the display position and interval enlargement ratio of each AF frame based on the enlargement ratio input by the user.

  Hereinafter, an AF frame display process executed in the digital camera according to the present embodiment will be described with reference to FIGS. 15 and 16.

  FIG. 15 is a flowchart illustrating the procedure of AF frame display processing of the digital camera according to the first example. In the default state (when electronic zoom is not set), it is assumed that the size and distance of the AF frame displayed on the display monitor 16 are stored in advance in a memory described later.

  In step S1, the body microcomputer 12 displays each AF frame on the display monitor 16 in a default state. In step S2, the body microcomputer 12 determines the presence / absence of electronic zoom. When the electronic zoom mode is not set, that is, when the magnification is 1.0, the process proceeds to step S3, and when it is set, the process proceeds to step S4.

  In step S3, the body microcomputer 12 continues to read each AF frame in the default state from a memory described later, and displays it in step S5.

  On the other hand, in step S4, the body microcomputer 12 detects the magnification set by the user. It is assumed that the magnification is N times (N> 1). In step S6, each AF frame with the display position and size multiplied by N is generated. In step S5, each AF frame is displayed on the display monitor 16.

  For example, when the electronic zoom magnification of 2 times is set, the body microcomputer 12 doubles the size of the AF frame and doubles the distance between the AF frames by the processing of steps S4 and S6. . As a result, the AF frames are displayed at positions and sizes corresponding to the enlargement ratio shown in FIG. Thereby, there is no deviation between the actual AF sensor position and the position of the subject image on the display monitor 16, and accurate focusing can be realized.

  FIG. 16 is a flowchart showing a procedure of AF frame display processing of the digital camera according to the second example. This process is executed when using the electronic zoom mode in which the number of recording pixels is set stepwise. “Setting the number of recording pixels in stages” means that the digital camera has A and B magnification electronic zoom settings. Steps S1, S2 and S3 are the same as the processing in FIG.

  In step S10, the body microcomputer 12 detects whether or not the electronic zoom magnification is A times. If it is A times, the process proceeds to step S11. If it is not A times, the process proceeds to step S12.

  In step S11, the body microcomputer 12 generates each AF frame enlarged by A times. On the other hand, in step S12, assuming that the enlargement ratio of the electronic zoom is B, which is another option, each AF frame enlarged to B times is generated.

  Through the processing in step S11 or step S12, each AF frame is displayed at the position and size corresponding to the enlargement ratio in step S5. Thereby, there is no deviation between the actual AF sensor position and the position of the subject image on the display monitor 16, and accurate focusing can be realized.

  In FIGS. 15 and 16, when each AF frame corresponding to the enlargement ratio is generated, calculation may be performed as needed according to the detected electronic zoom magnification. Alternatively, a plurality of display data of each AF frame enlarged according to the electronic zoom magnification may be stored in the memory in advance. Alternatively, a reference AF frame image is held in the memory, and a table describing a display position and an enlargement ratio corresponding to the electronic zoom magnification is stored in the memory inside the body microcomputer 12 or outside the body microcomputer 12. It may be held inside. Table 1 shows an example of such a table.

  The body microcomputer 12 may refer to the memory according to the enlargement ratio or reduction ratio of the image, read out necessary display position data and enlargement ratio data, and display the AF frame on the display monitor 16.

  The AF frame enlargement processing has been described so far. However, even when the image enlarged by the electronic zoom process is reduced, the body microcomputer 12 may reduce each AF frame at the position and size corresponding to the reduction ratio and display the AF frame on the display monitor 16.

  In FIG. 11 and the like, three AF frames are illustrated, but the number of AF frames is arbitrary. There may be more or less than three. The shape of each AF frame is also an example, and other shapes may be adopted.

  Next, the hardware configuration of the camera body 1 and the imaging lens device 2 according to the present embodiment will be described in detail with reference to FIGS. 17 and 18.

  FIG. 17 is a block diagram illustrating the control system of the camera body 1 according to the present embodiment.

  The body microcomputer 12 includes a shutter button 30, a shutter speed setting dial 31, a shooting / playback mode switching lever 71, a MENU button 72, a cross operation key 73, a SET button 74, a shooting mode switching button 75, and a narrowing down. Signals can be received from the mode button 76, the function button (1) 77, and the function button (2) 78. The body microcomputer 12 can transmit signals to the shutter control unit 14 and the quick return mirror control unit 43. Further, the body microcomputer 12 can communicate signals with each other among the image recording control unit 17, the image display control unit 15, and the signal processing unit 53. The body microcomputer 12 has a memory 68 for storing signals.

  The shutter control unit 14 drives a shutter drive motor 10 a (not shown) based on a control signal from the body microcomputer 12. The quick return mirror control unit 43 drives the quick return mirror drive motor 44 based on a control signal from the body microcomputer 12.

  The shutter button 30 transmits shutter timing to the body microcomputer 12. The shutter speed setting dial 31 transmits the set shutter speed information and shutter mode information.

  The image sensor 11 is a CCD (Charge Coupled Device) or the like. The imaging element 11 converts an optical image formed by the photographing optical system L of the imaging lens device 2 into an electrical image signal. The image sensor 11 is driven and controlled by the image sensor controller 13. The image signal output from the image sensor 11 is processed in the order of the signal processing unit 51, the A / D conversion unit 52, the signal processing unit 53, the buffer memory 54, and the image compression unit 56.

  The image signal is transmitted from the image sensor 11 to the signal processing unit 51. The signal processing unit 51 performs signal processing such as gamma processing on the image signal output from the image sensor 11. The image signal is transmitted from the signal processing unit 51 to the A / D conversion unit 52. The A / D conversion unit 52 converts the analog image signal output from the signal processing unit 51 into a digital signal.

  The image signal is transmitted from the A / D converter 52 to the signal processor 53. The signal processing unit 53 performs signal processing such as noise removal and edge enhancement on the image signal converted into a digital signal by the A / D conversion unit 52. Further, the signal processing unit 53 can perform an electronic zoom process on the image signal. The image signal is transmitted from the signal processing unit 53 to the buffer memory 54. The buffer memory 54 temporarily stores the image signal processed by the signal processing unit 53. The buffer memory 54 is a RAM (Random Access Memory). In addition, the signal processing unit 53 uses image data that has not been electronically zoomed, image data that has been electronically zoomed, or image data that is generated by performing predetermined processing on the image data as display image data. Output is possible.

  The image signal is transmitted from the buffer memory 54 to the image compression unit 56 in accordance with a command from the image recording control unit 17. The image compression unit 56 compresses the data of the image signal to a predetermined size in accordance with a command from the image recording control unit 17. The image signal is subjected to data compression at a predetermined ratio and has a smaller data size than the original data. For example, a JPEG (Joint Photographic Experts Group) method is used as this compression method.

  The compressed image signal is transmitted from the image compression unit 56 to the image reading / recording unit 18. On the other hand, the body microcomputer 12 transmits a control signal to the image recording control unit 17 and the image display control unit 15. The image recording control unit 17 controls the image reading / recording unit 18 based on a control signal from the body microcomputer 12. The image display control unit 15 controls the display monitor 16 based on a control signal from the body microcomputer 12.

  The image reading / recording unit 18 records the image signal in the internal memory and / or the removable memory based on a command from the image recording control unit 17. The image reading / recording unit 18 records information to be stored together with the image signal in the internal memory and / or the removable memory based on a command from the image recording control unit 17. Information to be stored together with the image signal includes date and time when the image was captured, focal length information, shutter speed information, aperture value information, and shooting mode information.

  The display monitor 16 displays the image signal as a visible image based on a command from the image display control unit 15. The display monitor 16 displays information to be displayed together with the image signal based on a command from the image display control unit 15. At this time, AF frame information is also displayed on the display monitor 16 based on a command from the image display control unit 15. Other information to be displayed together with the image signal includes focal length information, shutter speed information, aperture value information, shooting mode information, focus state information, presence / absence of the aperture ring 40 of the imaging lens device 2, and setting of the aperture value. There is information such as step and setting width.

  The display monitor 16 displays a setting screen to be set by a photographer or the like in a predetermined shooting / playback mode based on a command from the image display control unit 15.

  When a photographer or the like takes a picture, the power button 70 is turned on, and the photography / playback mode switching lever 71 is set to the photography mode. As a result, the camera body 1 is turned on, and the subject converted into an electrical image signal by the imaging device 11 is displayed on the display monitor 16 as a visible image based on a command from the image display control unit 15.

  When the photographer or the like presses the MENU button 72 while the camera body 1 is in the shooting mode, the display monitor 16 is a setting item that can be changed by the photographer or the like in the shooting mode based on a command from the image display control unit 15. Displays a setting menu image that is iconified.

  FIG. 18 is a block diagram illustrating a control system of the imaging lens device 2 according to the present embodiment.

  The lens microcomputer 20 can communicate signals with each other among the zoom control unit 62, the focus control unit 26, and the aperture control unit 27.

  The zoom control unit 62 can receive a signal from the zoom linear sensor 60 via the A / D conversion unit 61. The zoom control unit 62 converts the rotation amount of the zoom ring 38 detected by the zoom linear sensor 60 into focal length information of the photographing optical system L. The zoom control unit 62 transmits the focal length information to the lens microcomputer 20.

  The focus control unit 26 can receive a signal from the focus linear sensor 63 via the A / D conversion unit 64. The focus control unit 26 can transmit a signal to the focus drive motor 65. The focus control unit 26 determines the focus mode from the rotation angle of the focus ring 39 detected by the focus linear sensor 63 and digitized by the A / D conversion unit 64. The focus control unit 26 transmits the determined result to the lens microcomputer 20. The focus control unit 26 transmits object point distance information detected from the rotation angle of the focus ring 39 based on a command from the lens microcomputer 20 to the lens microcomputer 20. The focus control unit 26 drives the focus drive motor 65 based on a control signal from the lens microcomputer 20.

  The aperture control unit 27 can receive a signal from the aperture linear sensor 66 via the A / D conversion unit 67. The aperture control unit 27 can transmit a signal to the aperture drive motor 28b. The aperture control unit 27 determines the aperture mode based on the rotation angle of the aperture ring 40 detected by the aperture linear sensor 66 and digitized by the A / D conversion unit 67. The aperture control unit 27 transmits the determined result to the lens microcomputer 20. The aperture control unit 27 transmits aperture value information detected from the rotation angle of the aperture ring 40 based on a command from the lens microcomputer 20 to the lens microcomputer 20. The aperture control unit 27 drives the aperture drive motor 28b based on a control signal from the lens microcomputer 20.

  In the memory unit 69 in the lens microcomputer 20, various programs for each imaging lens device 2, data indicating the relationship between the focal length and the distance to the subject, and the amount of movement of the focus lens group 25, and whether or not the aperture ring 40 is mounted. Further, data such as aperture value setting steps and setting widths are stored.

  Next, the shooting operation of the camera body 1 will be described. As described above, the imaging apparatus according to the present embodiment has two shooting modes.

  First, based on FIG. 2, a driving sequence in a normal photographing mode in which a photographer or the like looks through the viewfinder eyepiece window 9 and performs photographing will be described.

  When the photographer or the like presses the shutter button 30 halfway, power is supplied to the body microcomputer 12 and various units in the camera body 1. The body microcomputer 12 in the camera body 1 activated by power supply receives various lens data from the lens microcomputer 20 in the imaging lens apparatus 2 similarly activated by power supply via the lens mount 21 and body mount 23, and is built in. Is stored in the memory 68. Next, the body microcomputer 12 acquires a defocus amount (hereinafter referred to as Df amount) from the focus detection unit 5 and instructs the lens microcomputer 20 to drive the focus lens group 25 by the Df amount. The lens microcomputer 20 controls the focus control unit 26 to operate the focus lens group 25 by the amount of Df. As described above, when the focus detection and the driving of the focus lens group 25 are repeated, the Df amount becomes small.

  After that, the body microcomputer 12 instructs the lens microcomputer 20 to make the aperture value calculated based on the output from the photometric sensor (not shown) by fully pressing the shutter button 30. Then, the lens microcomputer 20 controls the aperture controller 27 to narrow the aperture to the instructed aperture value. Simultaneously with the instruction of the aperture value, the body microcomputer 12 causes the quick return mirror control unit 43 to retract the quick return mirror 4 from the optical path X. After completion of the retraction, the image sensor control unit 13 instructs the image sensor 11 to be driven and instructs the operation of the shutter unit 10. Note that the image sensor control unit 13 exposes the image sensor 11 for the time of the shutter speed calculated based on the output from a photometric sensor (not shown).

  After the exposure is completed, the image sensor control unit 13 reads an image signal from the image sensor 11 and controls to display a captured image on the display monitor 16 after predetermined image processing, and also via the image reading / recording unit 18. The image signal is written to the storage medium. Further, after the exposure is completed, the quick return mirror 4 and the shutter unit 10 are reset to the initial positions. The body microcomputer 12 instructs the lens microcomputer 20 to reset the aperture to the open position, and the lens microcomputer 20 issues a reset command to each unit. After the reset is completed, the lens microcomputer 20 informs the body microcomputer 12 of the reset completion. The body microcomputer 12 waits for the reset completion information from the lens microcomputer 20 and the completion of the series of processes after exposure, and then confirms that the state of the shutter button 30 is not depressed, and ends the photographing sequence.

  Next, based on FIG. 3, a driving sequence in another live view mode in which a photographer or the like photographs using the display monitor 16 will be described.

  When shooting using the display monitor 16, the shooting mode switching button 75 is operated to set the live view mode. When shifting to the live view mode, the body microcomputer 12 retracts the quick return mirror 4 from the optical path X. Accordingly, since the subject image reaches the image sensor 11, the image sensor control unit 13 reads an image signal from the image sensor 11 and displays a captured image on the display monitor 16 after predetermined image processing. Here, the predetermined image processing includes processing for setting an image range when the first and / or second electronic zoom is set. Thus, by displaying the captured image on the display monitor 16, the photographer or the like can follow the subject without looking through the viewfinder eyepiece window 9. Here, an AF frame is displayed on the display monitor 16, and the photographer can accurately focus on a desired position in the captured image by aligning the subject to be focused on with the AF frame. Even when the electronic zoom is set, as described above, by displaying an AF frame of a predetermined size, a shift between the AF sensor position and the AF frame display position is eliminated, and accurate focusing is possible.

  Next, when the photographer or the like presses the shutter button 30 halfway, the body microcomputer 12 of the camera body 1 receives various lens data from the lens microcomputer 20 in the imaging lens device 2 via the lens mount 21 and the body mount 23. Is stored in the built-in memory. Next, the body microcomputer 12 returns the quick return mirror 4 to a predetermined position on the optical path X by the quick return mirror control unit 43, acquires the Df amount from the focus detection unit 5, and the focus lens for the Df amount. The lens microcomputer 20 is instructed to drive the group 25. The lens microcomputer 20 controls the focus control unit 26 to operate the focus lens group 25 by the amount of Df. As described above, the focus detection and the driving of the focus lens group 25 are repeated, and the Df amount becomes small. At this time, since the quick return mirror 4 has been returned to a predetermined position on the optical path X, the subject image does not reach the image sensor 11 and the display monitor 16 normally displays black, but the photographer does not You will feel uncomfortable. Therefore, the image displayed on the display monitor 16 immediately before the half-pressing operation of the shutter button 30 is displayed as a still image without making the display monitor 16 display black. By doing so, the photographer can shoot without feeling uncomfortable. Further, since the image displayed at this time is different from the image displayed in real time at the time of framing, a display such as “currently in AF operation” may be displayed on the display monitor 16 in order to show this. Usually, this AF operation is an operation that is performed for a very short time after the framing operation by the photographer is completed, and there is no big problem even if such a display is performed. You can shoot without feeling uncomfortable.

  After that, the body microcomputer 12 instructs the lens microcomputer 20 to make the aperture value calculated based on the output from the photometric sensor (not shown) by fully pressing the shutter button 30. Then, the lens microcomputer 20 controls the aperture controller 27 to narrow the aperture to the instructed aperture value. Simultaneously with the instruction of the aperture value, the body microcomputer 12 causes the quick return mirror control unit 43 to retract the quick return mirror 4 from the optical path X. After completion of the retraction, the image sensor control unit 13 instructs the image sensor 11 to be driven and instructs the operation of the shutter unit 10. Note that the image sensor control unit 13 exposes the image sensor 11 for the time of the shutter speed calculated based on the output from a photometric sensor (not shown).

  After the exposure is completed, the image sensor control unit 13 reads an image signal from the image sensor 11 and controls to display a captured image on the image display display monitor 16 after predetermined image processing, and the image reading / recording unit 18. The image signal is written to the storage medium via Further, after the exposure is completed, the quick return mirror 4 is located in a state of being retracted from the optical path X, and it is possible to continue the live view mode.

  Further, when canceling the live view mode, the shooting mode switching button 75 is operated to shift to a normal shooting mode, that is, a live view mode in which shooting is performed while looking through the viewfinder eyepiece window 9. At this time, the quick return mirror 4 is returned to a predetermined position on the optical path X. The quick return mirror 4 is also returned to a predetermined position on the optical path X when the camera body 1 is turned off.

  In this way, since the live view mode is installed, even a digital camera can be photographed using a display monitor, and it is not necessary to shoot through the viewfinder. For beginners, it becomes very easy to use. In addition, even when the electronic zoom is set, by displaying an AF frame of an appropriate size, a shift between the displayed AF frame and the AF sensor position can be eliminated, and an accurate focusing operation can be performed. Further, during the AF operation in the live view mode, by displaying the image on the display monitor 16 without being interrupted, it is possible to shoot without making the photographer feel uncomfortable.

  In the embodiment, an example in which a zoom lens system is provided as an imaging lens device has been described. However, an imaging lens device having a single focus lens system that does not have an optical zoom function may be attached. Even in this case, the first electronic zoom mode is a mode in which the enlargement magnification is determined based on the number of recording pixels, and the second electronic zoom mode is the same as the mode for accepting the enlargement magnification itself. . The size of the displayed AF frame is also set to a size corresponding to the set number of recording pixels in the first electronic zoom mode, and to a set enlargement magnification in the second electronic zoom mode. By displaying an AF frame of a corresponding size, an accurate focusing operation can be performed.

  The present invention can be applied to a digital still camera and a digital video camera, and is particularly suitable for a single-lens reflex type digital still camera.

It is a figure which shows the structure of the digital camera by this embodiment. It is a figure which shows the optical path in the camera main body 1 in normal imaging | photography mode. It is a figure which shows the optical path in the camera main body 1 in live view mode. It is a top view of the camera main body 1 which attached the imaging lens apparatus 2 which concerns on this embodiment. It is a rear view of the camera main body 1 which concerns on this embodiment. (A) And (b) is a figure which shows the example of a display in the display monitor 16 when turning on or off each of digital zoom mode and EX optical zoom mode. (A)-(c) is a figure which shows the image processing of EX optical zoom mode. (A)-(c) is a schematic diagram explaining the principle when EX optical zoom mode is utilized with the zoom function of a lens. (A)-(c) is a figure which shows the image processing of digital zoom mode. (A)-(c) is a schematic diagram explaining the principle when digital zoom mode is utilized with the zoom function of a lens. 4 is a diagram illustrating an example of AF frames A and B displayed on a display monitor 16. FIG. FIG. 6 is a diagram illustrating an example in which AF frames 122 to 124 are displayed superimposed on a subject image. It is a figure which shows the relationship between the electronic zoom frame 121 and a to-be-photographed image. It is a figure which shows AF frames 130-132 shown with the broken line in the example of FIG. It is a flowchart which shows the procedure of the AF frame display process of a digital camera by the 1st example. It is a flowchart which shows the procedure of the AF frame display process of a digital camera by the 2nd example. It is a block diagram which shows the control system of the camera main body 1 by this embodiment. It is a block diagram which shows the control system of the imaging lens apparatus 2 by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera main body 2 Imaging lens apparatus 4 Quick return mirror 9 Finder eyepiece window 10 Shutter unit 11 Imaging element 12 Body microcomputer 14 Shutter control part 15 Image display control part 16 Display monitor 18 Image reading / recording part 20 Lens microcomputer 21 Lens mount 23 Body Mount 25 Focus lens group 27 Aperture control unit 28 Aperture unit 28a Aperture blade 28b Aperture drive motor 30 Release button 31 Shutter speed setting dial 33 Index 38 Zoom ring 39 Focus ring 40 Aperture ring 41 Aperture linear sensor 43 Quick return mirror control unit 44 Quick Return mirror drive motor 62 Zoom control unit 65 Focus drive motor 69 Imaging lens device internal memory 71 Shooting / playback mode Switching lever 72 MENU button 75 shooting mode switching button 76 refine mode button 77 function button (1)
78 Function buttons (2)

Claims (5)

An imaging device detachably connected to an imaging lens device,
The imaging lens device has an imaging lens system for forming a subject image,
A movable mirror capable of switching the position where the subject image is formed to one of a first position and a second position by being inserted into and extracted from the optical path;
An image sensor that is disposed at the first position and that captures the subject image to generate an image signal;
A signal processing unit that performs an image enlargement process or a reduction process based on the image signal, and generates a processed image signal;
A focus sensor that detects a focus signal indicating a focus state of a part of the subject image based on the subject image when the subject image is formed at the second position;
A display device for displaying an image based on the image signal;
A control unit that controls generation of a focus frame that is further displayed on the display device, and the focus frame is displayed at a position on the image corresponding to a part of the subject image, and the focus sensor is focused. An imaging apparatus that indicates a position for detecting a state, and wherein the control unit changes the display of the focus frame and displays the focus frame on the display device in accordance with the enlargement process or the reduction process of the image in the signal processing unit.   The imaging device according to claim 1, wherein the control unit changes the size of the focus frame according to a magnification rate or a reduction rate of the image in the signal processing unit and displays the size on the display device. There are a plurality of the focus frames,
The imaging device according to claim 2, wherein the control unit changes the distance between the focus frames in accordance with an enlargement rate or a reduction rate of the image in the signal processing unit and displays the distance on the display device. The control unit further includes a memory that holds data indicating a plurality of display modes of the focus frame in correspondence with an enlargement rate or a reduction rate of the image in the signal processing unit,
The control unit refers to the memory according to an enlargement rate or reduction rate of the image in the signal processing unit, reads one of the data indicating the plurality of display modes, and the focus frame based on the read data The imaging device according to claim 2, wherein the size of the image is changed and displayed on the display device.   5. The data according to claim 4, wherein the memory holds data indicating a plurality of display modes having different display positions and enlargement ratios of the focus frame in correspondence with the enlargement ratio or reduction ratio of the image in the signal processing unit. Imaging device.

Images