JP2007248616A - Focusing state display device for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focusing state display device for achieve focus by easy, accurate manual focusing without providing the function of calculating a focus evaluation value. <P>SOLUTION: The focusing state display device includes: an imaging section 2; a focus evaluation value computing section 4 that calculates an evaluation value based upon the image signal output from the imaging section 2, the focus evaluation value being used to evaluate the current degree of focus of a subject image; a peak detecting section 6 detecting that the focus evaluation value exceeds a peak value during its change, with reference to the evaluation value output from the focus evaluation value computing section 4; a focus meter forming section 8 forming a focus meter image that visually expresses the focus evaluation value, based on the focus evaluation value output from the focus evaluation value computing section 4; a display section 10 that outputs a composite image obtained on a monitor 12 as a result of image composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-focus state display device for a camera capable of manual focusing, and more particularly to an in-focus state display device for a camera capable of displaying a level of an in-focus state.

  In general, in manual focus (hereinafter referred to as MF) in a digital camera, a user observes a subject with a viewfinder or an electronic viewfinder (EVF) while manually rotating a photographing lens, and is considered to have the best focus. A method of stopping the movement of the photographing lens at the lens position is performed.

  However, in the MF as described above, it cannot be said that the lens position at which the user stopped the photographing lens is the lens position at which the best focusing state can be obtained due to factors such as the user's ability and the viewability of the viewfinder.

  On the other hand, as autofocus (hereinafter referred to as AF) of a digital camera, an evaluation value (hereinafter referred to as a focus evaluation value) representing the degree of focus is calculated by performing a predetermined calculation on the output of the image sensor, There is known a method for obtaining the best in-focus state by moving the photographing lens to the lens position of the photographing lens when the focus evaluation value becomes a peak value. The focus evaluation value indicates the magnitude of the high frequency component of the video signal, and indicates a higher value as the focus state is reached. Therefore, it is possible to detect the lens position where the best focus state can be obtained by scanning the lens position where the focus evaluation value becomes the peak value. This AF method is called the name of mountain climbing AF, imager AF, or contrast AF.

  By the way, as a technique for using the focus evaluation value for focusing in MF, for example, the following techniques are known.

  First, Patent Document 1 discloses a camera device that performs real-time display of a focused state level. Patent Document 2 discloses an electronic camera that displays information on the position of a photographing lens and displays information on a focus evaluation value in a bar. Further, Patent Document 3 discloses an imaging apparatus that displays a graph in which the horizontal axis indicates the position of the photographing lens and the vertical axis indicates the focus evaluation value. Patent Document 4 discloses a video camera that displays a difference between in-focus evaluation values before and after MF in a display form in which the polarity and size can be identified.

As described above, according to the techniques disclosed in Patent Documents 1 to 4, a relatively accurate MF is realized as compared with a commonly performed MF.
JP-A-6-113184 JP 2001-42207 A JP 2003-262910 A JP 2005-181373 A

  By the way, the absolute value of the focus evaluation value varies greatly depending on the nature of the subject, contrast, brightness, camera shake, and the like. This is not a big problem because it is only necessary to search the peak value of the focus evaluation value when performing hill-climbing AF.

  However, in the techniques disclosed in Patent Documents 1 to 4, even when performing MF, the amount depending on the absolute value of the focus evaluation value is used as it is as a display of the level of the focus state. For this reason, in the technologies disclosed in Patent Documents 1 to 4, the focus evaluation value changes at a high level, for example, depending on the subject, or changes at a low level. As a result, with the techniques disclosed in Patent Documents 1 to 4, accurate focusing by MF is difficult. Further, it is particularly difficult to focus when the focus evaluation value changes at a low level. Furthermore, since the display level of the degree of focus varies greatly depending on the subject, the user feels very uncomfortable.

  Although this problem is slightly mitigated by the technique disclosed in Patent Document 4, that is, a technique for displaying a difference, the subject dependency is still high.

  The present invention has been made in view of the circumstances as described above, and is a camera that performs hill-climbing AF, and in a MF-capable camera, an in-focus state in which focusing with MF can be performed easily and accurately. An object is to provide a display device.

  In order to achieve the above object, an in-focus state display device according to an aspect of the present invention includes an imaging lens capable of adjusting an imaging position of a subject image by being driven by a focusing operation by a photographer, An imaging unit that forms the subject image through the imaging lens and converts the subject image into a video signal, and a focus evaluation value that is an index for evaluating the in-focus state of the subject image in the imaging unit. Evaluation value calculating means for calculating based on the video signal output from the imaging means; display means for displaying the focus evaluation value calculated by the evaluation value calculating means in a graphic shape; and And a display switching means for switching at least one of the graphic shape and the display form of the graphic shape in accordance with a change in the focus evaluation value.

  The present invention can provide an in-focus state display device that can easily and accurately focus on MF in a camera that performs hill-climbing AF and that can perform MF.

  Hereinafter, an in-focus state display device according to an embodiment of the present invention will be described with reference to the drawings, taking a camera having a so-called hill-climbing AF function as an example.

[First embodiment]
First, the main configuration of the in-focus state display device according to the present embodiment will be described with reference to the block diagram shown in FIG. Details of the operation control will be described later with reference to other drawings.

  Reference numeral 2 indicates that a subject image is formed through a photographing lens of a camera equipped with the in-focus state display device according to the present embodiment, and the formed subject image is photoelectrically converted. It is an imaging unit that converts video signals. And this imaging part 2 outputs the said video signal to the focus evaluation value calculating part 4 mentioned later.

  The focus evaluation value calculation unit 4 calculates a focus evaluation value for evaluating the degree of focus of the subject image at the current time point based on the video signal output from the imaging unit 2. The peak detection unit 6 refers to the in-focus evaluation value output from the in-focus evaluation value calculation unit 4 and detects that the in-focus evaluation value has passed the peak value during the changing process. It is. That is, the peak detection unit 6 determines that the focus evaluation value has passed the peak value in the process of changing the focus evaluation value due to the driving (focusing operation) of the photographing lens performed by the user of the camera. Is detected.

  Here, the focus meter creation unit 8 creates a focus meter image that visually represents the focus evaluation value based on the focus evaluation value output from the focus evaluation value calculation unit 4. . The focus meter image represents the AF focus evaluation value in a graphic shape, and details will be described later with a specific example. The focus meter creation unit 8 changes the display scale of the focus meter image according to a signal indicating that the focus evaluation value output from the peak detection unit 6 has passed the peak value. The display scale will be described later in detail.

  Then, the display unit 10 synthesizes the video signal output from the imaging unit 2 and the focus meter image output from the focus meter creation unit 8, and creates an image created by the synthesis, for example, It outputs to the monitor 12 which consists of LCD etc. That is, the monitor 12 is a member for displaying an image generated by the display unit 10.

  FIG. 2 is a block diagram showing in detail the configuration of a camera equipped with the in-focus state display device according to the present embodiment. In the following, with reference to the figure, the components of the camera will be described in detail by taking AF performed by a normal camera as an example.

  The correspondence between the constituent members of the focus state display device shown in the block diagram of FIG. 1 and the constituent members of the camera shown in the block diagram of FIG. 2 is as follows. That is, the functions of the imaging unit 2 are performed by, for example, the imaging optical system 102, the diaphragm 104, the shutter unit 208, the imaging element 212, and the imaging interface circuit 217 shown in FIG. The function by the focus evaluation value calculation unit 4, the function by the peak detection unit 6, the function by the focus meter creation unit 8, and the function by the display unit 10 include, for example, an image processing controller 218 shown in FIG. It is carried by the buffer memory 219. The function of the monitor 12 is performed by, for example, a liquid crystal monitor 222 shown in FIG.

  The function by the imaging unit 2, the function by the focus evaluation value calculation unit 4, the function by the peak detection unit 6, the function by the focus meter creation unit 8, and the function by the display unit 10 are described later. A control microcomputer (hereinafter referred to as Bucom) 201 instructs the image processing controller 218 and the buffer memory 219 to sequentially execute the processes.

  First, as shown in FIG. 2, a camera equipped with the in-focus state display device according to this embodiment includes a lens barrel 100 and a camera body 200.

  Here, each part of the lens barrel 100 is controlled by a lens control microcomputer (hereinafter referred to as Lucom) 101. On the other hand, each unit of the camera body 200 is controlled by the Bucom 201. Here, when the lens barrel 100 is attached to the camera body 200, the Lucom 101 and the Bucom 201 are communicably connected via the communication connector 101a. In this case, as a camera system, the Lucom 101 is operated so as to be subordinate to the Bucom 201.

  A photographing optical system 102 is disposed inside the lens barrel 100. Here, in FIG. 2, a plurality of optical lenses (photographing lenses) constituting the photographing optical system 102 are representatively illustrated as one optical lens. The photographing optical system 102 is moved in the optical axis direction by a DC motor (not shown) existing in the lens driving mechanism 103.

  A diaphragm 104 is provided behind the photographing optical system 102. The diaphragm 104 is driven to open and close by a stepping motor (not shown) existing in the diaphragm drive mechanism 105. By controlling the opening and closing of the diaphragm 104, the amount of light flux from the subject incident on the camera body 200 via the photographing optical system 102 is controlled.

  Here, the control of the DC motor in the lens driving mechanism 103 and the control of the stepping motor in the diaphragm driving mechanism 105 are performed by the Lucom 101 that has received a command from the Bucom 201. Further, when the focus ring 106 which is a rotatable member provided on the outer periphery of the lens barrel 100 is rotated by the user, the photographing optical system 102 is driven by the lens driving mechanism 103 in synchronization with the rotation. The That is, the focus ring 106 is a member for manual focus by the user.

  In addition, a finder device including a main mirror 202a, a pentaprism 202c, and an eyepiece 202d is provided inside the camera body 200. When the camera is in a normal state, a part of the light beam from the subject incident through the photographing optical system 102 is reflected by the main mirror 202a. Thereby, an image for observation is formed through the pentaprism 202c and the eyepiece lens 202d.

  Here, a photometric circuit 204 is provided in the vicinity of the pentaprism 202c, and a part of the light beam that has passed through the pentaprism 202c enters a photosensor (not shown) in the photometric circuit 204. In the photometry circuit 204, a well-known photometry process is performed based on the light amount of the light beam detected by the photosensor. The result processed by the photometry circuit 204 is transmitted to the Bucom 201.

  In the Bucom 201, the exposure amount at the time of photographing is calculated based on the result input from the photometry circuit 204. This result is transmitted from Bucom 201 to Lucom 101. In the Lucom 101, drive control of the diaphragm 104 is performed based on the exposure amount notified from the Bucom 201.

  The light beam transmitted through the main mirror 202a and reflected by the sub mirror 203 is guided to an AF sensor unit 205 for performing an automatic focus adjustment process (AF process). An area sensor (not shown) is provided inside the AF sensor unit 205, and a light beam incident on the area sensor is converted into an electric signal.

  The output from the area sensor is transmitted to the Bucom 201 via the AF sensor driving circuit 206. Then, ranging processing is performed in the Bucom 201, and the focus state (defocus amount) of the photographing optical system 102 necessary for focus adjustment is calculated. The calculation result is transmitted from Bucom 201 to Lucom 101. In the Lucom 101, drive control of the photographing optical system 102 is performed based on the movement amount notified from the Bucom 201.

  By the way, when the camera is in the photographing operation state, the main mirror 202a is moved to a predetermined up position where it is retracted from the optical axis of the photographing optical system 102. Such driving of the main mirror 202 a is performed by the mirror driving mechanism 207. The mirror drive mechanism 207 is controlled by the Bucom 201. Here, when the main mirror 202a is moved to the up position, the sub mirror 203 is folded accordingly.

  As the main mirror 202 a is moved to the up position in this way, the light beam from the subject that has passed through the photographing optical system 102 enters the direction of the shutter unit 208. The light beam that has passed through the shutter unit 208 is then incident on the image sensor 212 disposed behind the shutter unit 208. Note that the shutter unit 208 is a focal plane shutter that includes a front curtain and a rear curtain. Here, the spring force for driving the front curtain and the rear curtain is charged by the shutter charge mechanism 209. The front curtain and the rear curtain are driven by the shutter control circuit 210. The shutter charge mechanism 209 and the shutter control circuit 210 are controlled by the Bucom 201.

  The luminous flux of the subject image formed by the image sensor 212 is converted into an electrical signal (video signal). The electrical signal is read out and digitized via the imaging interface circuit 217 at every predetermined timing. Then, the image data obtained by digitization by the imaging interface circuit 217 is stored in a buffer memory 219 constituted by an SDRAM or the like via an image processing controller 218. Here, the buffer memory 219 is a memory for temporarily storing data such as image data, and is used as a work area when various processes are performed on the image data. Further, the buffer memory 219 temporarily stores data related to processing executed by the focus evaluation value calculation unit 4, the peak detection unit 6, the focus meter creation unit 8, and the display unit 10 in FIG. It is a memory to do.

  Thereafter, the image processing controller 218 reads the image data read out via the imaging interface circuit 217 and stored in the buffer memory 219. Image data read by the image processing controller 218 is subjected to known image processing such as white balance correction, gradation correction, and color correction, and then stored in the buffer memory 219. At the time of image recording, the image data processed by the image processing controller 218 is compressed by a known compression method such as the JPEG method. The JPEG data obtained by the JPEG compression is stored in the buffer memory 219 and then recorded on the FlashRom 220 or the recording medium 221 as a JPEG file to which predetermined header information is added.

  Here, the FlashRom 220 is assumed to be a memory built in the camera, and the recording medium 221 is assumed to be mounted outside the camera. As the recording medium 221, for example, a memory card or a hard disk drive configured to be detachable from the camera is used.

  Further, when an image is played back from the JPEG file recorded on the FlashRom 220 or the recording medium 221, the JPEG data recorded on the FlashRom 220 or the recording medium 221 is read and decompressed by the image processing controller 218. Is done. Thereafter, the decompressed data is converted into a video signal, resized to a predetermined size for display, and output and displayed on the liquid crystal monitor 222.

  The Bucom 201 is connected to a nonvolatile memory 223 that stores predetermined control parameters necessary for camera control. The non-volatile memory 223 is composed of, for example, a rewritable EEPROM. Further, a battery 225 as a power source is connected to the Bucom 201 via a power circuit 224. The voltage of the battery 225 is converted to a voltage required by each part of the camera system by the power supply circuit 224 and supplied to each part of the camera system.

  The Bucom 201 includes an operation display LCD 226 for notifying the user of the operation state of the camera by display output, and a camera operation SW (camera operation switch) 227 for detecting operation states of various operation members of the camera. And are connected.

  By the way, when electronic viewfinder (EVF) display is performed in the camera, image data read out via the imaging interface circuit 217 and stored in the buffer memory 219 is read out by the image processing controller 218. It is. The image data read by the image processing controller 218 is subjected to image processing such as white balance correction for EVF display, and then stored in the buffer memory 219 separately from the read image data. Thereafter, the image data stored in the buffer memory 219 is read out by the image processing controller 218 in units of frames and converted into video signals. The video signal is resized to a predetermined size for display and then output and displayed on a liquid crystal monitor 222 as display means. The user can check the captured image from the image displayed on the liquid crystal monitor 222.

  If the operation control of EVF display as described above is performed, display generally referred to as a through image can be performed. In order to display a through image, the following operation control is usually performed. That is, first, the main mirror 202a is moved to the up position, and the shutter unit 208 is opened. As a result, the imaging light flux directly enters the image sensor 212. Thereafter, the image data acquired by the image sensor 212 by shooting at a predetermined frame rate (the number of shot images per second) is read by the image processing controller 218 and displayed on the liquid crystal monitor 222. By observing the through image display on the liquid crystal monitor 222, the user can observe the subject image without looking into the eyepiece.

  Hereinafter, various operation members used by the user of the camera will be described with reference to FIG. 3 showing a rear view of the camera equipped with the in-focus state display device according to the present embodiment.

  As shown in the figure, on the back of the camera 1, a main dial 316, an AF frame button 317, an AE lock button 318, a playback mode button 319, a delete button 320, a protect button 321 and an information display button are displayed. 322, a menu button 323, a cross button 324, an OK button 325, and a live button 326 are provided. A mode dial 303 is provided on the upper surface of the camera 1. Hereinafter, each member will be described sequentially.

  First, the main dial 316 is a member for changing the setting of the function related to the operation member currently pressed by the user by being rotated.

  The mode dial 303 is a member for setting various shooting modes. Here, the mode dial 303 will be described by taking a scene mode (SCN) as an example of the various shooting modes. That is, when the main dial 316 is rotated by the user while the mode dial 303 is set to SCN, the liquid crystal monitor 222 displays a menu screen related to setting of shooting conditions according to a desired scene. Is done. Here, examples of the desired scene include portraits, sports, commemorative photography, landscapes, night scenes, and the like. Various shooting conditions such as exposure, flash emission, photometry mode, AF method, and continuous shooting interval are set according to the scene selected by the user.

  The AF frame button 317 is a button for selecting an AF method at the time of shooting. When the main dial 316 is operated while the AF frame button 317 is being pressed, the AF method is changed to, for example, multi AF or spot AF.

  In the multi AF, the focus state of a plurality of ranging points in the screen is detected. On the other hand, in the spot AF, the focus state of one point (can be selected from a plurality of candidates) in the screen is detected.

  The AE lock button 318 is a button for fixing exposure conditions. While the AE lock button 318 is being pressed, the exposure amount calculated at that time is fixed.

  The playback mode button 319 is a button for switching the operation mode of the camera 1 to a playback mode in which an image can be reproduced and displayed on the liquid crystal monitor 222 from a JPEG file recorded on the FlashRom 220 or the recording medium 221.

  The delete button 320 is a button for deleting the image data (JPEG file) from the FlashRom 220 and the recording medium 221 during the playback mode.

  The protect button 321 is a button for protecting the image data so that the image data is not accidentally erased during the reproduction mode.

  The information display button 322 is a button for causing the liquid crystal monitor 222 to display image information based on additional information (for example, Exif information) of image data.

  The menu button 323 is a button for displaying a menu screen on the liquid crystal monitor 222. This menu screen is composed of menu items having a plurality of hierarchical structures. The user can select a desired menu item with the cross button 324 and can determine the item selected with the OK button 325. Here, the menu items include, for example, a setup menu for the FlashRom 220 and the recording medium 221, a shooting menu capable of setting image data quality, image processing, scene mode, and the like, playback conditions during image playback, and settings during image printing. There are a playback menu that allows the user to perform various operations, a custom menu that allows various fine settings according to the photographer's preference, a setup menu that sets the operating state of the camera such as the type of warning sound, and the like.

  The live button 326 is a button for selecting a mode for displaying the above-described through image. Hereinafter, a mode for displaying a through image is referred to as a live view mode. When the live button 326 is pressed by the user, display of a through image on the liquid crystal monitor 222 is started (entering the live view mode). Thereafter, when the live button 326 is pressed again, the live view mode is exited. During the live view mode, since the main mirror 202a is in the up position, no light beam enters the AF sensor unit 205. That is, in this case, the AF operation is impossible. Therefore, when the live view mode is entered, the Bucom 201 switches the AF operation state to the MF operation state.

  The contents set by the operation of each operation member by the user are stored in the buffer memory 219 or a memory (not shown) in the Bucom 201.

  Hereinafter, an actual in-focus state display scene by the in-focus state display device according to the present embodiment will be described with reference to FIGS.

  First, as described above, when the user presses the live button 326, the camera enters a live view mode. At this time, the liquid crystal monitor 222 starts displaying a through image of the subject.

  When the camera enters the live view mode, the enlargement box 230 for designating an enlargement area is displayed in the display screen of the liquid crystal monitor 222 as shown in FIG. 4A (in FIG. 4A). Does not depict the subject).

  Here, the enlarged box 230 shown in FIGS. 4A and 4B is a display that can be moved to a user desired area on the liquid crystal monitor 222 as shown in FIG. 4A. Therefore, the user selects the enlargement box 230 so as to overlap the desired area including the image of the portion to be enlarged and displayed. The enlargement box 230 is moved by operating the cross button 324 by the user. In other words, the user operates the cross button 324 to move the enlargement box 230 to a position desired by the user within the display screen of the liquid crystal monitor 222. Thereafter, when the user operates the OK button 325, an enlarged display of the region where the enlargement box 230 is overlaid is performed on the liquid crystal monitor 222 (see FIG. 4C).

  Thus, in the live view mode, the user can enlarge and display an arbitrary area. The purpose of the enlarged display of such an arbitrary area is to make it easier for the user to focus at the time of MF. Hereinafter, a description will be given along a time series.

  Here, as shown in FIGS. 4B and 4C, for example, when an area including the head of the subject 231 is enlarged and displayed, the head of the subject 231 is included by the operation of the cross button 324 by the user. When the enlargement box 230 is aligned with the area and then the OK button 325 is pressed, the head area of the subject 231 is enlarged and displayed on the liquid crystal monitor 222 as shown in FIG. Mode). Hereinafter, the mode for performing the enlarged display as shown in FIG. 4C is referred to as an enlarged mode. In this way, the image (see FIG. 4B) in the area of the enlargement box 230 whose position is set by the user uses the entire display screen of the liquid crystal monitor 222 as shown in FIG. 4C. The enlarged display is made.

  Here, in the enlargement mode, the image of the area in the enlargement box 230 (in this example, the image of the head of the subject 231) is enlarged and displayed on the liquid crystal monitor 222. A 50% area of the entire display screen from the center of the liquid crystal monitor 222 in the vertical and horizontal directions is a focus evaluation value calculation area 232. That is, the focus evaluation value in the focus evaluation value calculation area 232 is calculated every predetermined frame rate.

  The focus evaluation value calculated in the focus evaluation value calculation area 232 is displayed as a display bar 241 in the focus meter 240 on the right side of the display screen on the liquid crystal monitor 222 as shown in FIG. 4C, for example. Is displayed. Here, the longer the length of the display bar 241, the higher the focus evaluation value (the higher the degree of focus), and the shorter the length of the display bar 241, the lower the focus evaluation value (the lower the degree of focus). . Although the focus evaluation value display bar 241 is displayed only in the enlargement mode here, the focus meter 240 and the display bar are similarly displayed in the non-enlargement mode shown in FIG. Of course, 241 may be displayed.

  The calculation for expressing the focus evaluation value as the display bar 241 in the focus meter 240 will be described later.

  Hereinafter, the flow of operation control processing in the Bucom 201 in the shooting operation in the live view mode will be described with reference to the flowchart shown in FIG. Note that the detailed operation control of the constituent members of the camera is as described above with reference to FIG. 2, and therefore, the processing flow will be mainly described here.

  A release switch (not shown) in the camera is a general two-stage switch. That is, the first release switch is turned on by being half pressed by the user, and the second release switch is turned on by being fully pressed. The photographing operation is executed when the second release switch is turned on.

  First, when the transition operation to the live view mode described above is performed (when the user presses the live button 326), the camera enters the live view mode. At this time, the series of processes described above with reference to FIGS. 4A to 4C is performed by a user operation. Since this is not the gist of the present invention, its details are omitted. After the process in the previous stage of the live view mode is performed, the process proceeds to the process of the flowchart illustrated in FIG.

  First, the live view mode operation in the in-focus state display device according to the present embodiment is performed, and display of a through image of the subject is started on the liquid crystal monitor 222. (Step S1). Here, step S1 will be described in detail later with reference to another flowchart. When the release button (not shown) is fully pressed by the user during the live view mode operation in step S1, the second release switch is turned on. Thereby, the processing of the live view mode operation in step S1 is completed. Then, the main mirror 202a is driven through the mirror driving mechanism 207 from the up position to the down position (initial position) which is the position of the main mirror 202a shown in FIG. 2 (step S2). This step S2 is a step for executing a photometric operation.

  Next, photometry is performed by the photometry circuit 204, and the aperture time of the shutter unit 208 and the aperture value of the aperture 104 are calculated (step S3). Then, the main mirror 202a is driven to the up position by the mirror driving mechanism 207 (step S4). Further, the diaphragm 104 is driven based on the diaphragm value calculated in step S3 (step S5).

  Thereafter, driving of the image sensor 212 is started to start an imaging operation (step S6). The shutter unit 208 is opened based on the opening time calculated in step S3 and is closed again (step S7). After closing the shutter unit 208, the driving of the image sensor 212 is stopped, and the image interface circuit 217 reads pixel data in the image sensor 212 (step S8). Here, the image processing controller 218 performs image processing on the pixel data read from the image sensor 212 in step S8 (step S9).

  Then, the image data processed in step S9 is temporarily stored in the buffer memory 219 (step S10). Further, the diaphragm 104 is returned to the open position (step S11). Thereafter, an image file of the image data is generated (step S12). In step S12, an image file of the image data is generated as a mode in which the image data temporarily stored in the buffer memory 219 in step S10 is written to the recording medium 221. Then, the image file of the image data generated in step S12 is recorded on the recording medium 221 (step S13). Thereafter, the process returns to step S1 to resume the live view.

  Hereinafter, the end operation of the live view mode will be described with reference to FIG. 5B, which is a flowchart showing the flow of processing in the Bucom 201 when the operation of the live view mode ends. Note that, when the live button 326 is pressed by the user during the live view mode operation in step S1, the process proceeds to the process of the flowchart shown in FIG.

  First, the live view display on the liquid crystal monitor 222 is terminated (step S21). Subsequently, the MF operation state set during the live view mode is canceled, and the AF operation state set before the live view mode is set again (step S22).

  Then, the opened shutter portion 208 is closed (step S23). Further, with the closing of the shutter unit 208, the driving of the image sensor 212 is stopped (step S24). Subsequently, the main mirror 202a is driven to the down position which is the initial position (step S25). Then, it will be in a standby state.

  Hereinafter, with reference to FIG. 6, a display example of an index for manual focus, which is one of the characteristic parts of the focus state display device according to the present embodiment, will be described. Here, FIG. 6A is a diagram illustrating the relationship between the focus evaluation value and the lens position of the photographing optical system 102 in the present embodiment. FIG. 6B is a diagram illustrating an example of display of the focus evaluation value at each lens position illustrated in FIG. FIG. 6C is a diagram showing an example of display of the focus evaluation value in the process of movement (3) shown in FIG.

As shown in FIG. 6A, the focus evaluation value at the time when the mode is switched to the enlargement mode is set as AF _ref which is a reference focus evaluation value. Then, the lens position of the photographing optical system 102 at this time is set as the lens position L2, and in this example, the focus evaluation value AF _ref at the lens position L2 is in a considerably low state (a state that is considerably out of focus). To do. It should be noted that the focus evaluation value calculation is repeatedly performed by the Bucom 201 at a predetermined frame rate from when the mode is switched to the enlargement mode.

  First, for the user, when the lens position of the photographing optical system 102 is moved from the lens position L2 by the rotation operation of the focus ring 106, the user can first rotate the focus ring 106 in which rotation direction. In this case, it is unclear whether the focus state is approached.

  Therefore, the user once rotates the focus ring 106 in any desired direction to move the position of the photographing optical system 102. For example, here, when the position of the photographing optical system 102 becomes the position of the lens position L1 shown in FIG. 6A, the focus evaluation value becomes lower as shown in FIG. Becomes worse (movement (1)). In such a case, the user only has to rotate the focus ring 106 in the opposite direction.

  Therefore, when the user rotates the focus ring 106 in the opposite direction, the position of the photographing optical system 102 passes from the lens position L1 through the lens position L2 to the lens position L5. The focus evaluation value at the position L5 is a peak value (the most focused state).

  However, even when the position of the photographing optical system 102 is the lens position L5 and the focus evaluation value becomes a peak value, it is unknown to the user whether or not the value is the peak value at that time. . Accordingly, it is considered that the user continues the rotation operation of the focus ring 106 even after the position of the photographing optical system 102 becomes the lens position L5 (movement (2)).

  For example, when the position of the photographing optical system 102 is the lens position L6, the display image is slightly out of focus compared to the time of the lens position L5. Therefore, the user recognizes that the in-focus position has been passed, and performs an operation of rotating the focus ring 106 in the reverse direction (movement (3)) to the lens position L5.

Incidentally, in this example, as can be seen from FIGS. 6A to 6C, the focus evaluation value at the lens position L2 is set as a reference focus evaluation value AF _ref . As described above, in the present embodiment, the focus evaluation value at the time of switching to the enlargement mode is used as the reference value of the focus evaluation value.

  In the process in which the photographing optical system 102 moves (moves (1)) from the lens position L2 to the lens position L1, the focus evaluation value decreases.

At this time, the Bucom 201 calculates, for example, a value (AF _level ) to be displayed as the display bar 241 in the focusing meter 240 by performing the calculation of the following equation (1).

When AF _now <AF _ref :
Display value AF _level = 10 × (AF _now / AF _ref )} − 5 (1)
The AF _now indicates the latest focus evaluation value at the time of the calculation. Further, when AF _level <0 in the calculation in the above formula (1), AF _level = 0 is set. As can be seen from FIG. 6B, as the lens position of the photographing optical system 102 approaches the position of the lens position L1 from the lens position L2, the value of AF _level becomes smaller.

Here, as can be seen from the above equation (1), when AF _now <AF _ref , the ratio of AF _now to AF _ref is calculated in calculating the value displayed as the display bar 241 in the focusing meter 240. Is calculated by multiplying by 10. Therefore, if the user rotates the focus ring 106 in the direction opposite to the direction of approaching the in-focus state, the display on the display bar 241 is rapidly shortened as shown in FIG. Therefore, the user can clearly and easily recognize that the rotation operation is not an operation toward focusing.

  On the other hand, in the process of movement (movement (2)) of the lens position of the photographing optical system 102 from the position of the lens position L2 to the position of the lens position L6, the focus evaluation value increases. At this time, the Bucom 201 calculates a value to be displayed as the display bar 241 in the focusing meter 241 by performing, for example, the following equation (2).

When AF _now ≧ AF _ref :
Display value AF _level = log ₂ (AF _now / AF _ref ) +5 (2)
As can be seen from the above equation (2), AF _level = 5 when the lens position of the photographing optical system 102 is at the lens position L2, and therefore the display bar 241 is positioned at the center ( AF _level is aligned with a line indicating 5). Thereafter, the value of AF _level increases with the movement from the lens position L2, and when the position of the lens position L5, which is the lens position with the highest degree of focusing, passes, the value of AF _level decreases conversely. .

Here, the reason why AF _now , which is one of the features of the present embodiment, is normalized by AF _ref and displayed will be described.

  As described above, the absolute value of the focus evaluation value varies greatly depending on the nature of the subject, such as the contrast, brightness, or camera shake. Therefore, when the method of displaying the focus evaluation value on a linear scale is adopted, the display bar 241 may shake greatly or slightly due to changes in the subject, shooting conditions, and the like. In this case, although the peak value of the focus evaluation value can be detected, it is not convenient for a general user who has little knowledge about the focus evaluation value. In other words, it cannot be said that the focusing meter 240 plays a sufficient role for facilitating manual focusing.

Therefore, in the present embodiment, the focus evaluation value is displayed after being converted into a value normalized by a predetermined value. Then, it was considered that the evaluation value AF _ref at a lens position that is significantly out of focus is appropriate as a standardization base. This is because the peak value of the focus evaluation value (focus evaluation value at the lens position L5) can be set as AF _peak , and the range of the value of AF _peak -AF _ref can be increased. Therefore, even if the absolute value of the focus evaluation value varies greatly depending on the subject and shooting conditions, the range between AF _{peak and} AF _ref can be sufficiently obtained by standardizing with AF _ref as in the present embodiment. Large and within a predetermined range. That is, the display range (here, 5 to 10) of the focusing meter 240 can be optimized.

  Next, the reason for performing the compression operation by logarithmic compression in the above equation (2) will be described.

First, the absolute value of the focus evaluation value varies depending on the calculation method, but the ratio between AF _peak and AF _ref is several tens of times. Therefore, if the focus evaluation value is displayed on the linear scale, the display range of the focus meter 240 cannot be set appropriately. In view of such a fact, in this embodiment, logarithmic compression is performed as shown in the above equation (2). As a result, since the AF _level can be displayed from 5 to 10, it is possible to deal with a range in which AF _peak and AF _ref are 2 ⁵ = 32 times.

Depending on the method of calculating the focus evaluation value, when the ratio of AF _peak and AF _ref is smaller, logarithmic compression may not be performed, and the compression method may not be logarithmic.

  FIG. 6C shows the movement (2) shown in FIG. 6A, that is, the case where the lens position of the photographing optical system 102 is moved to the lens position L6 by the rotation operation of the focus ring 106 by the user. After the user recognizes that the peak value of the focus evaluation value has been passed by visually recognizing the display bar 241, the user rotates the focus ring 106 in the reverse direction, and the lens position becomes the lens position. The display of the display bar 241 in the process of returning to the position L5 (the position where the degree of focus is highest) is shown. FIG. 6C also shows a process of passing through the lens position L5 again at this time (movement (3)). In this case, when the operation is performed again to return to the lens position L5, the reverse of the example shown in FIG. 6C is followed (movement (3) shown in FIG. 6A).

  The operation control in the Bucom 201 for actually displaying the focus evaluation value shown in FIG. 6 in the live view mode will be described below with reference to the flowchart shown in FIG. The flowchart shown in FIG. 7 is also a flowchart showing in detail the process of step S1 in the flowchart shown in FIG. In addition, steps in the same flowchart that perform the same processing are denoted by the same step numbers and description thereof is also omitted.

  In the live view mode, the AF mode cannot be used. Therefore, even if the AF mode is selected by an AF mode selection switch (not shown) for switching to the AF mode, the mode is first forcibly switched to the MF mode (step S31). That is, in the process in step S31, the mode is switched to the MF mode in order to execute the live view mode.

  Subsequently, the main mirror 202a is moved to the up position, and the shutter unit 208 is opened (step S32). As a result, the total luminous flux enters the image sensor 212 through the opening. Thereafter, input of a synchronization signal is awaited (step S33). Here, the synchronization signal is a signal for driving the image sensor 212 at predetermined intervals to obtain a video signal. For example, when the frame rate is 30 frames / s, the video signal is obtained 30 times per second. That is, in this case, a synchronization signal is input from the imaging interface circuit 217 every 33.33 ms.

  Thereafter, when it is determined that the synchronization signal has been input, the imaging interface circuit 217 performs the charge accumulation operation of the imaging element 212 (step S34). When the charge accumulation operation of the image sensor 212 is completed, the image data is read by the image interface circuit 217 (step S35). Thereafter, a known calculation is performed on the current imaging data to calculate an AE evaluation value for evaluating exposure, and an exposure amount at the next driving time of the image sensor 212 is calculated based on the calculation result (step S36). Here, the imaging element 212 has a known electronic shutter function, and sets the charge accumulation time according to the exposure amount calculated and calculated in step S36.

Subsequently, the focus evaluation value in the setting area (here, the setting area is the focus evaluation value calculation area 232 shown in FIG. 4C; the same applies hereinafter) is calculated, and the alignment serving as a reference after that is calculated. The focus evaluation value is AF _ref (step S37). The focus evaluation value is a value obtained by performing high-pass filter processing on the output of the image sensor 212 to extract a high-frequency component and performing a known calculation, and various calculation formulas have been known conventionally. ing. In addition, this focus evaluation value becomes a large value because the higher the focus, the higher the frequency component.

  By the way, after the processing in step S37 is completed, the process waits for the next synchronization signal to be input (step S33A). Here, when the synchronization signal is detected, steps S34A to S36A, which are the same processes as those in steps S34 to S36 described above, are executed.

When the processing in step S36A is completed, a focus evaluation value in the set area is calculated, and the obtained value is set as a focus evaluation value AF _now (step S38). Subsequently, the magnitude of the AF _ref value and the AF _now value is determined (step S39). That is, in this step S39, it is determined whether or not AF _now <AF _ref .

When step S39 is branched to YES, AF _now / AF _ref is uncompressed as the value of AF _level displayed as the display bar 241 according to the above-described equation (1) (step S40). Then, it waits for the next synchronization signal.

On the other hand, when step S39 is branched to NO, since AF _now ≧ AF _ref , AF _now / AF _ref is compression-calculated as the AF _level value displayed as the display bar 241 according to the above-described equation (2). (Step S41). Then, it waits for the next synchronization signal.

  Hereinafter, the steps of the interrupt process will be described.

  First, during the processing in steps S33 to S41, if the second release switch is turned on by the user while the live view display update operation is being performed at a predetermined frame rate, the Bucom 201 In the interrupt process, the sequence in the flowchart is exited, and the process proceeds to the process of step S2 described with reference to FIG. 5A, and the photographing operation is performed (step S42).

  If the user presses the live button 326 while the live view display update operation is being performed at a predetermined frame rate during the processing in steps S33 to S41, the Bucom 201 interrupt processing is performed. Then, the sequence in the flowchart is exited, and the process proceeds to step S21 described with reference to FIG. 5B, and the end operation of the live view mode is performed (step S43).

  As described above, according to the present embodiment, an in-focus state display device that provides the following effects can be provided.

First, according to the in-focus state display device according to the present embodiment, the in-focus evaluation value at the lens position (initial value) of the photographing optical system 102 in a largely out-of-focus state is set as the reference value AF _ref . When the focus ring 106 is rotated by the user in the direction of the focus evaluation value smaller than the AF _ref value, the focus meter 240 is based on the AF _level calculated by the non-compression calculation process. The display bar 241 is displayed. Accordingly, if the focus ring 106 is rotated in a direction opposite to the direction toward the in-focus state, the display bar 241 is suddenly shortened, so that the user should rotate the focus ring 106. You can immediately recognize that the direction is the opposite direction.

Conversely, when the focus ring 106 is rotated in the direction toward the in-focus state, the display bar 241 in the in-focus meter 240 is displayed based on the AF _level calculated by the compression calculation process.

By performing the display control as described above, even when the ratio of the AF _peak and the AF _ref is increased to some extent, the display of the display bar 241 in the focusing meter 240 is shaken out. There is nothing.

  Further, according to the focus state display device according to the present embodiment, the swing width of the display bar 241 in the focus meter 240 is set to a predetermined level regardless of the subject condition, regardless of the subject condition. Can keep. That is, the display bar hardly shakes even when the subject reaches the in-focus point on the subject under certain conditions, and conversely, the subject display bar 241 shakes to near the maximum value with the subject under other conditions.

  Furthermore, according to the in-focus state display device according to the present embodiment, since the display bar 241 starts to swing from the center of the in-focus meter 240, the in-focus state display is very easy for the user.

[Modification]
Hereinafter, a modification of the first embodiment will be described. An object of the present modification is to simplify the operation of resetting the AF _ref once set. According to the present modification, for example, when the subject is changed, it is possible to omit the troublesomeness of resetting the AF _ref (an operation to exit the enlargement mode and then enter the enlargement mode again).

  The flowchart shown in FIG. 8 is a flowchart obtained by changing a part of the flowchart shown in FIG. Therefore, among the steps in the flowchart shown in FIG. 8, steps that perform the same processing as the steps in the flowchart shown in FIG. Hereinafter, step S44 which is a characteristic part of this modification will be described.

First, when a display start switch (not shown) is pressed by the user, the process proceeds to step S44 in the interrupt process of Bucom 201. Here, in step S44, the focus evaluation value is calculated as described above from the captured image at the time when the display start switch (not shown) is pressed by the user, and the calculated value is set as AF _ref again. Thereafter, the process returns to the step where the process was performed before the interruption in step S44.

As described above, according to the present modification, in addition to the effects achieved by the focus state display device according to the first embodiment, a focus state display device that provides the following effects can be provided. That is, according to this modification, a new AF _ref can be set by an easy operation as described above, and the newly set AF _ref is then used in the processing in step S39. The display of 240 is completely updated. That is, according to the present modification, it is possible to provide an in-focus state display device that can easily display the display bar 241 in the in-focus meter 240 from the initial setting when the subject is changed.

  As the display start switch, a dedicated switch may be provided, or a switch that is also used as another switch may be used.

[Second Embodiment]
Hereinafter, an in-focus state display device according to a second embodiment of the present invention will be described with reference to the drawings.

  FIGS. 9A to 9C are diagrams showing an example of display of a focus evaluation value that is an index for manual focus, which is one of the features of the focus state display device according to the present embodiment. is there. Here, FIG. 9A is a diagram illustrating the relationship between the focus evaluation value and the lens position of the photographing optical system 102 in the present embodiment. FIG. 9B is a diagram illustrating an example of display of the focus evaluation value at each lens position illustrated in FIG. FIG. 9C is a diagram showing an example of display of the focus evaluation value in the process of movement (3) shown in FIG.

  FIG. 9 corresponds to FIG. 6 in the first embodiment described above. In particular, in this embodiment, regarding the movement (1) and movement (2), the same display as that of the movement (1) and movement (2) shown in FIG. 6 in the first embodiment is performed. Therefore, here, the difference between the in-focus state display device according to the first embodiment and the in-focus state display device according to the present embodiment will be mainly described.

FIG. 9B is a diagram illustrating a case where the lens position of the photographing optical system 102 has moved to the lens position L6 in the process of the movement (2). As can be seen from the figure, in the process of this movement (2), the value of the focus evaluation value has passed its maximum value AF _peak . In the present embodiment, judgment in such a case, the effect that had passed the maximum value AF _peak focus evaluation value in order to recognize the user, and passes through the maximum value AF _peak focus evaluation value ( (Hereinafter referred to as peak crossing determination), the display form of the focus evaluation value, that is, the display form of the display bar 241 is switched. The details of the algorithm for determining the peak excess will be described later with reference to FIG.

  That is, in the present embodiment, once the peak is exceeded, it is determined that the peak has been exceeded by the peak excess determination algorithm, and the display form of the display bar 241 is as shown in FIG. Switching (in the example shown in FIG. 9, the display color is black → red).

  In addition, the display of the display bar 241 at the lens position L6 in FIG. 9B is a slight moment (during a time lag) between the time when the peak is exceeded and the time when the display mode of the display bar 241 is switched. It is a transient display that is displayed.

  As described above, specifically, the switching of the display form includes, for example, changing the display color. In the example shown in FIG. 9C, when it is determined that the peak has been exceeded, the display color of the display bar 241 is switched to red (the normal display color of the display bar 241 is black). In addition, it is possible to switch the display form such that the texture pattern of the display bar 241 is striped or the display position of the display bar 241 on the liquid crystal monitor 222 is changed. That is, it is only necessary to switch the display form so that the user can recognize the peak overshoot.

  Here, the movement (3) shown in FIGS. 9A and 9C is performed by a reverse rotation operation of the focus ring 106 by the user (operation of reverse rotation with respect to the rotation direction when the peak is exceeded). The display of the display bar 241 is shown in the moving process in which the lens position of the photographing optical system 102 is returned to the lens position L5 (the lens position in the best focus state). FIG. 9C shows a display when the photographing optical system 102 passes through the lens position L5 again and returns to the lens position L1.

  Furthermore, this embodiment has the following features that are not found in the first embodiment. That is, in the present embodiment, the range of the display bar 241 is changed before and after the determination of exceeding the peak. Thereby, the MF operation by the user becomes easier.

Specifically, since the focus evaluation value range (AF _peak -AF _ref ) from the initial position to the in-focus position is known in the process up to the movement (2), logarithm compression display is performed before the determination of exceeding the peak. The display scale in the vicinity of the AF _peak can be enlarged and displayed by changing the AF display of the display bar 241 to the non-compressed display based on the following equation after the determination of _{exceeding the peak} .

After peak over judgment:
Display value AF _level = 10 × (AF _now / AF _peak )} − 2 (3)
As a result, when AF _now = AF _peak is set to AF _level = 8, the focus evaluation value can be displayed on the display bar 241 in a linear scale in the range of 0 to 10.

  Hereinafter, with reference to FIG. 10, the algorithm for determining the peak excess will be described.

FIG. 10A is a diagram for explaining a peak crossing algorithm when a rotation operation of the focus ring 106 is performed by the user so that the peak crossing determination can be correctly determined. That is, in this example, the focus ring 106 is rotated in one direction by the user until the peak is exceeded. In this case, after the peak is exceeded, when the Bucom 201 determines that the focus evaluation value has decreased by a predetermined amount from the maximum value (when it is determined that the value of AF _peak -AF _now is greater than the predetermined value), The display form of the display bar 241 is switched.

Then, the user who recognizes that the peak has been exceeded by switching the display mode of the display bar 241 rotates the focus ring 106 in the direction opposite to that until the switching of the display mode. The lens position of the photographing optical system 102 is moved to AF _peak .

On the other hand, FIG. 10B is a diagram for explaining the peak crossing algorithm when the user rotates the focus ring 106 in reverse before the peak crossing is achieved. In this case, the Bucom 201 must not determine that the focus evaluation value immediately before the reverse rotation operation is the maximum value AF _peak . For this purpose, it is determined that the focus ring 106 is continuously rotated in only one direction, or the rotational direction is the same before and after the focus evaluation value reaches its maximum value AF _peak (inverted). The Bucom 201 may perform the determination of not being performed.

That is, the Bucom 201 may not set the AF _peak unless the rotation direction is the same before and after the in-focus evaluation value reaches the maximum value AF _peak .

  Here, in order to detect the rotation direction, for example, the focus is detected by the output of a lens position monitor circuit (not shown) in the lens driving mechanism 103 (for example, a photo interrupter output pulse or an encoder output). The Bucom 201 may detect the rotation direction of the ring 106 via the Lucom 101. In this manner, the Bucom 201 can appropriately perform the peak overrun determination by detecting the rotation direction of the focus ring 106.

  Hereinafter, the operation control in the Bucom 201 for actually displaying the focus evaluation value shown in FIG. 10 in the live view mode will be described with reference to the flowcharts shown in FIGS. Note that the flowcharts shown in FIGS. 11 to 12 are also flowcharts showing in detail the process of step S1 in the flowchart shown in FIG. Further, steps that perform the same processing as the steps in the flowchart shown in FIG.

  First, when it is determined in step S33 that the synchronization signal has been input, lens position data (data indicating the rotation direction of the focus ring 106) is acquired from the Lucom 101 (step S45). Here, as described above, a lens position monitor circuit (not shown) in the lens driving mechanism 103 is used.

In step S37, a focus evaluation value in the set area is calculated and set as a focus evaluation value AF _ref as a reference thereafter. After that, the value of AF _peak is used as an initial value AF _ref ( It is initialized to AF _peak = AF _ref ) (step S46). The value of the AF _peak is used in step S49 described later. Subsequently, a peak exceeding flag flag_peak used for peak exceeding determination described later is initialized to 1 (step S47).

  After step S47, if it is determined in step S33A that performs the same processing as step S33 that the synchronization signal has been input, the latest lens position data is acquired in the same manner as in step S45. (Step S48).

Thereafter, the processes in steps S34A to S36A, which perform the same processes as in steps S34 to S36, are performed. In step S38 described above, the focus evaluation value in the set area is calculated, and the obtained value is calculated. after the _{AF now} as the current focus evaluation value, the magnitude of the value of the _{AF now} value and the focus evaluation value _{AF peak} (initial value set in step S46, then the updated set at step S50 to be described later) Are compared (step S49).

When step S49 is branched to YES, AF _peak <AF _now and the focus evaluation value has not yet reached the peak value. In this case, AF _peak = AF _now is substituted (step S50). Thereafter, the process proceeds to step S39. Therefore, the path to step S50 is continued until the focus evaluation value reaches the peak value.

On the other hand, when step S49 is branched to NO, AF _peak ≧ AF _now . In this case, it is determined whether or not the value of AF _peak -AF _now has reached a predetermined amount (whether AF _peak -AF _now <predetermined value) (step S51).

When this step S51 is branched to YES, if the value of AF _peak -AF _now has not reached the predetermined amount, that is, the peak value of the focus evaluation value has passed, but the focus evaluation value of the focus evaluation value has been slightly changed from the peak value. This is the case when the value has not decreased. In this case, the process proceeds to step S39.

  By the way, the case where step S51 is branched to NO is a case where it is determined that the focus evaluation value has sufficiently decreased after reaching the peak value. In this case, the logic of the peak over flag flag_peak (whether flag_peak = 0) is determined (step S52).

  Here, after the transition to the live view mode, if the focus ring 106 continues to be rotated after passing the peak value of the focus evaluation value for the first time, flag_peak = 1 is set in step S47. Therefore, step S52 is branched to NO, and the process proceeds to step S53 described later.

  The case where step S52 is branched to NO is a case where it is determined that the focus evaluation value has sufficiently decreased after reaching the peak value. In this case, it is determined whether or not the rotation direction of the focus ring 106 is the same before and after the peak value (step S53). The determination in step S53 is performed with reference to the lens position data acquired in step S48, that is, the lens position data before and after the focus evaluation value reaches the peak value.

Even after the transition to the live view mode, when the focus ring 106 continues to be rotated only in the direction in which the focus evaluation value decreases, the process proceeds to step S53. At this time, the value of AF _{peak is} the value set in step S46 (AF _ref, which is a focus evaluation value when shifting to the live view mode). Therefore, the AF _peak value at this time cannot be said to be a true peak value. In this case, the process proceeds to step S54, which will be described later, in order to branch to NO in step S53.

  That is, when step S53 is branched to NO, it is determined that the in-focus evaluation value has sufficiently decreased after reaching the peak value, and the focus before and after the in-focus evaluation value reaches the peak value. This is a case where the rotation direction of the ring 106 is not the same. In this case, the peak over flag flag_peak = 0 is set (step S54).

Note that when step S53 is branched to NO in the state shown in FIG. 10B, it should be determined that the value of AF _peak in this case is not a true peak value. Accordingly, in this case, the peak over flag flag_peak = 0 is set in step S54, and the next step S52 branches to YES, and the process proceeds to step S55.

  On the other hand, when step S53 is branched to YES, it is determined in step S51 that the in-focus evaluation value has sufficiently decreased after reaching the peak value, and before and after the in-focus evaluation value reaches the peak value. This is a case where it is determined in step S53 that the rotation direction of the ring 106 is the same. Since this case is the state shown in FIG. 10A, the display form of the display bar 241 is switched as described with reference to FIG. 9C (step S58). That is, here, as described above, the display color of the display bar 241 is changed.

Then, after the display form is switched in step S58, the AF _level value displayed as the display bar 241 is calculated according to the equation (3) (step S59). Note that the calculation in step S59 is an uncompressed calculation of AF _now / AF _peak as described above.

  Thereafter, when it is determined in step S33B that performs the same processing as step S33 that the synchronization signal has been input, the processing of step S48A that performs the same processing as the processing of step S48 is performed, and further, the above-described step S34 is performed. The process of step S34B thru | or step S37B which performs the process similar to the said step S37 is performed.

  In the series of processing steps from step S59 to step S37B, when a display start switch (not shown) is pressed by the user, the process proceeds to step S60 in the interrupt processing of Bucom 201. This step S60 is a step for moving to step S33 in order to perform live view display from the beginning again (step S60). In other words, step S60 is a process in the case where the live view display is restarted from the beginning after the peak crossing determination. Of course, as the interrupt process in the series of processes in steps S59 to S37B, the interrupt process in steps S42, S43, and S44 can be executed.

  Incidentally, when step S52 is branched to YES, the focus ring 106 is reversely rotated by the user before the focus evaluation value reaches the peak value. In this case, it is determined whether or not the rotation direction of the focus ring 106 has been reversed again (that is, whether or not the photographing optical system 102 has been moved in a direction in which the focus evaluation value is directed toward the peak value again) (step S55). . Here, step S55 is branched to NO until the rotation direction of the focus ring 106 is reversed again. That is, in such a case, the process always moves to step S39.

On the other hand, when step S55 is branched to YES, the focus ring 106 is reversely rotated before the focus evaluation value reaches the peak value, and then the reverse rotation operation is performed again. In this case, the peak excess flag flag_peak set to 0 in step S54 is set to 1 again (step S56). Then, after a step _S56, to update settings of _{AF peak} value of _{AF now} as the value of the _{AF peak} (step S57).

  As described above, according to the second embodiment, it is possible to provide an in-focus state display device that provides the following effects in addition to the effects achieved by the in-focus state display device according to the first embodiment. I can do it.

  First, according to the focus state display device according to the present embodiment, when the focus evaluation value passes the peak value due to the user's operation of the focus ring 106, the display form of the display bar 241 is switched. Can immediately recognize that.

  Further, in the display form after the switching, as described above, the compressed display is switched to the non-compressed display as described above. Therefore, the expansion / contraction width of the display bar 241 with respect to the change of the focus evaluation value increases, and the display bar by the user Focusing on the MF while watching 241 becomes very easy.

[Third Embodiment]
Hereinafter, with reference to FIG. 13, a focused state display device according to a third embodiment of the present invention will be described. The difference between the second embodiment and the present embodiment is that a peak hold display 242 described later is performed in the present embodiment.

  FIGS. 13A to 13C correspond to FIGS. 9A to 9C in the second embodiment described above. Therefore, only the difference between the in-focus state display device according to the second embodiment and the in-focus state display device according to the present embodiment will be described here. In addition, the display of the display bar 241 at the lens position L6 in FIG. 13B is a slight moment (during a time lag) between the time when the peak is exceeded and the time when the display mode of the display bar 241 is switched. It is a transient display that is displayed.

In the present embodiment, in the process of the movement (2), as shown in FIG. 13B, a peak hold display 242 is displayed at the scale position of the display bar 241 corresponding to the peak value of the focus evaluation value up to the present time. indicate. As shown in FIGS. 13B and 13C, the peak hold display 242 is a display that allows the user to recognize the scale position reached by the longest display bar 241 up to the present time. is there. From this peak hold display 242, the user can know the peak value of the focus evaluation value up to that point. Therefore, when the lens position of the photographing optical system 102 becomes the lens position L6 in the process of the movement (2), the user can recognize that the AF _peak has been passed.

  That is, until the lens position of the photographic optical system 102 reaches the lens position L5, since the focus evaluation value at that time is the peak value at that time, the scale position of the peak hold display 242 is constantly updated. After the lens position of the photographing optical system 102 passes the lens position L5, the peak hold display 242 at the time of the lens position L5 is continuously maintained.

This is because the focus evaluation value when the lens position of the photographing optical system 102 is the lens position L5 is a peak value, that is, AF _peak . Accordingly, as shown in FIG. 13C, once the display form of the display bar 241 is switched, the peak hold display 242 at the lens position L5 is continuously maintained.

  In addition, regarding the flowchart of the operation control for realizing the peak hold display 242, for example, step S50 of the flowchart shown in FIG. 11 in the second embodiment may be changed as follows.

That is, in step S50, AF _peak ← AF _now is substituted, and the value of the AF _peak is displayed as the display bar 241 as the display value of the peak hold display 242 (step S50).

  As described above, according to the present embodiment, in addition to the same effects as the in-focus state display device according to the second embodiment, the in-focus state display device that provides the following effects is provided. Can do.

  That is, according to the in-focus state display device according to the present embodiment, since the peak hold display 242 is displayed in the in-focus meter 240, the in-focus operation with the MF by the user becomes easier. As described above, after the display form of the display bar 241 is switched (in this embodiment, the display color is changed to red), the user simply displays the peak hold display on the top surface of the display bar 241. This is because an in-focus state can be obtained by operating the focus ring 106 so as to coincide with the position 242.

  As mentioned above, although this invention was demonstrated based on 1st Embodiment thru | or 3rd Embodiment, this invention is not limited to embodiment mentioned above, A various deformation | transformation and application are within the range of the summary of this invention. Of course it is possible.

  For example, in each of the above embodiments, the case where the in-focus state display device in each embodiment is mounted on a single-lens reflex camera with interchangeable lenses has been described as an example, but other hill-climbing AF functions and MF functions Of course, the above-described embodiments can also be applied to other types of cameras having a combination of the above and the like, that is, still cameras, video cameras, and the like.

  In each of the above embodiments, the focus meter 240 is configured to indicate the degree of focus by the length of the display bar 241. However, if the user can recognize and determine at a glance, the display Of course, the degree of focusing may be expressed by the shape of another figure instead of the bar 241. For example, instead of the display bar 241, a circular display indicator is employed, and the degree of focus is expressed by the radius of the circular display indicator. Further, an example in which a triangular indicator having a fixed size is employed instead of the display bar 241 and the degree of focus is expressed by moving the triangular indicator in the liquid crystal monitor 222 within a predetermined range from side to side. It is done.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

The block diagram which shows the main structures of the focusing state display apparatus which concerns on 1st Embodiment. The block diagram which showed in detail the structure of the camera carrying the in-focus state display apparatus which concerns on 1st Embodiment. The figure which shows the rear view of the camera carrying the focusing state display apparatus which concerns on 1st Embodiment. The figure which shows the display screen in the liquid crystal monitor at the time of live view mode. (A) is a flowchart showing the flow of operation control processing in Bucom of the shooting operation in the live view mode in the camera equipped with the in-focus state display device according to the first embodiment. FIG. 6B is a flowchart showing the flow of processing in Bucom when the operation of the live view mode is terminated. (A) is a figure which shows the relationship between the focus evaluation value in 1st Embodiment, and the lens position of an imaging optical system. (B) is a figure which shows an example of a display of the focus evaluation value in each lens position shown to (a). (C) is a figure which shows an example of a display of the focus evaluation value in the process of the movement (3) shown to (a). 7 is a flowchart showing operation control in Bucom for actually displaying the focus evaluation value shown in FIG. 6 in the live view mode. 8 is a flowchart in a modification of the first embodiment, and is a flowchart obtained by changing a part of the flowchart shown in FIG. 7. (A) is a figure which shows the relationship between the focus evaluation value in 2nd Embodiment, and the lens position of an imaging optical system. (B) is a figure which shows an example of a display of the focus evaluation value in each lens position shown to (a). (C) is a figure which shows an example of a display of the focus evaluation value in the process of the movement (3) shown to (a). The figure which shows the algorithm of peak crossing judgment. The 1st part of the flowchart which shows the operation control in the live view mode of 2nd Embodiment. The 2nd part of the flowchart which shows the operation control in the live view mode of 2nd Embodiment. (A) is a figure which shows the relationship between the focus evaluation value in 3rd Embodiment, and the lens position of an imaging optical system. (B) is a figure which shows an example of a display of the focus evaluation value in each lens position shown to (a). (C) is a figure which shows an example of a display of the focus evaluation value in the process of the movement (3) shown to (a).

Explanation of symbols

    DESCRIPTION OF SYMBOLS 2 ... Imaging part, 4 ... Focus evaluation value calculating part, 6 ... Peak detection part, 8 ... Focus meter preparation part, 10 ... Display part, 12 ... Monitor, 101 ... Microcomputer for lens control, 102 ... Shooting optical system 103 ... Lens drive mechanism, 105 ... Aperture drive mechanism, 106 ... Focus ring, 201 ... Microcomputer for body control, 202a ... Main mirror 204 ... Photometry circuit, 205 ... AF sensor unit, 208 ... Shutter unit, 212 ... Imaging element 217: Imaging interface circuit, 218 ... Image processing controller, 219 ... Buffer memory, 221 ... Recording medium, 222 ... Liquid crystal monitor, 230 ... Expansion box, 232 ... Focus evaluation value calculation area, 240 ... Focus meter, 241 ... Display bar, 242 ... Peak hold display, 303: Mode dial, 316: Main dial, 317: AF frame button, 326: Live button

Claims (10)

An imaging lens capable of adjusting the imaging position of a subject image by being driven by a focusing operation by a photographer;
Imaging means for forming the subject image through the imaging lens and converting the subject image into a video signal;
Evaluation value calculation means for calculating a focus evaluation value, which is an index for evaluating the focus state of the subject image in the imaging means, based on a video signal output from the imaging means;
Display means for expressing and displaying the in-focus evaluation value calculated by the evaluation value calculating means in a graphic shape;
Display switching means for switching at least one of the graphic shape and the graphic shape display mode in accordance with the change in the focus evaluation value;
An in-focus state display device comprising:   The display switching means switches the display form of the graphic shape when detecting that the focus evaluation value has passed a peak value in the process of changing the focus evaluation value. The in-focus state display device according to 1.   The in-focus state display device according to claim 1, wherein the switching of the graphic form display form is switching of at least one of a display color and a texture pattern of the graphic.   4. The graphic shape switching is any one of a length of the graphic shape in a predetermined direction, a size of the graphic, and a display position of the graphic. A focus display device according to any one of the above. The figure shape is a rectangle,
The in-focus state display device according to claim 4, wherein the length in the predetermined direction of the figure shape is a length in the longitudinal direction of the rectangle.   The display means normalizes the figure shape at the predetermined time point to a predetermined shape based on the focus evaluation value calculated by the evaluation value calculation means at a predetermined time point. The in-focus state display device according to any one of 1 to 5.   The in-focus state display device according to claim 6, wherein the predetermined time is a display start time of the graphic shape by the display means.   The in-focus state display device according to claim 6, wherein the predetermined time point is a time point designated by the photographer. In the switching of the figure shape, the first change pattern in which the figure shape changes linearly as the focus evaluation value increases, and the rate of change in the figure shape decreases as the focus evaluation value increases. There are two patterns with the second change pattern going on,
The in-focus state according to claim 6, wherein the display switching unit switches the display form of the graphic shape according to any one of the first change pattern and the second change pattern. Status display device.   The display switching means switches the graphic shape according to the second change pattern when the evaluation value calculation means calculates a value equal to or higher than the focus evaluation value calculated at the predetermined time point, The in-focus state display device according to claim 9, wherein when the evaluation value calculating means calculates a value less than the in-focus evaluation value calculated at the predetermined time point, the evaluation value calculating means switches with the first change pattern.

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