JP2008298956A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inform an operator of a direction in which a focus lens should be driven for focusing. <P>SOLUTION: The drive of a focus ring is decided (S21). Whether an evaluated value of focusing is higher than the previous value is decided (S22). When deciding that it is higher, it is discriminated as a situation that the operator turns the focus ring in a focusing direction, and the driving direction of display is kept as it is (S23). When deciding that it becomes lower, it is discriminated as a situation that the operator turns the focus ring in a reverse direction, and the driving direction on the display is reversed (S23) and displayed (S25). When deciding that the focus ring is not driven, the driving direction is displayed in the focusing direction thereafter because operator's driving direction has been already recognized. When the focus ring is driven (S21), whether the evaluated value is higher than the previous value is decided (S22). If it becomes higher, the display is kept as it is (S23), and if it becomes lower, the display is reversed (S24) and the driving direction is displayed (S25). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus capable of displaying focusing information or a driving direction of a focus ring to notify an operator when manual focus is set.

  In an imaging apparatus such as a single-lens reflex camera, a half mirror disposed between the imaging element and the imaging optical system is used to guide the light beam from the imaging optical system to the finder optical system and the focus detection unit, thereby Image observation and automatic focusing are performed. Alternatively, the photographing operation is performed by retracting the mirror from the photographing optical path and causing the light beam from the photographing optical system to reach the image sensor. Further, when the reflecting mirror is arranged in the photographing optical path, focus adjustment is performed by the phase difference detection method, and when the reflecting mirror is retracted from the photographing optical path, focus adjustment is performed by the contrast detection method using the output of the image sensor. There is something to do.

  In recent years, there has been proposed a technique for performing focus adjustment by a contrast detection method in a live view mode in which an image read from an image sensor is displayed on an EVF (electronic viewfinder). This is because in the live view mode, the reflecting mirror is retracted from the photographing optical path, and only focus adjustment by the contrast detection method can be performed.

  In this way, all operations important for shooting such as exposure determination and focusing are automated, and the possibility of shooting failure even by an unskilled camera operator is extremely low. However, on the other hand, there is also a demand to set the exposure, focus, etc. as desired by the operator and take a picture.

  In focusing, there is known one in which the focus lens can be manually moved and the focus can be controlled so that the operator can manually focus on a desired position. Using this function, when shooting in the live view mode, the operator tries to shoot so that the subject image displayed on a monitor such as an EVF or LCD (liquid crystal display device) becomes the clearest. At this time, in order to assist the operator, not to leave it to the operator completely, it is digitally displayed how much the focus is on the monitor and in what direction and how much the focus ring is turned to focus. Is desirable.

  Therefore, as disclosed in Patent Document 1, an imaging element is disclosed that calculates a contrast evaluation value of image data corresponding to an image within a focus frame, generates a histogram of the focus lens position and the contrast evaluation value, and displays the histogram on a finder image. .

JP 2003-262910 A

  However, when the screen is about the size of the monitor, it is difficult for the operator to determine the sharpness of the subject image, and there is a problem that the focus lens is mistakenly moved in the direction opposite to the focal point. As a solution, there is a method of displaying the rotation direction of the focus ring in the in-focus direction. For this purpose, the camera needs to determine the drive direction of the focus ring.

  In the contrast detection method, the camera side does not know whether the desired in-focus position is on the near side or on the far side. Although there is a method of detecting the absolute position of the focus lens, there is a problem that a position detection sensor is required and an increase in cost is inevitable.

  An object of the present invention is to provide an imaging apparatus that solves the above-described problems and can notify an operator of a focusing operation direction.

  In order to achieve the above object, the technical feature of the image pickup apparatus according to the present invention is that image input means for obtaining an image signal of a subject via a photographing optical system and a high-frequency component in a specific area of the image signal are extracted and combined. In an imaging apparatus having an evaluation value calculation means for calculating a focus evaluation value and a lens driving means for manually moving a focus lens to control a focused state, the focus lens should be driven first by the lens driving means An initial driving direction determining means for determining an initial driving direction; and when the lens driving means is driven in the direction determined by the initial driving direction determining means, the driving direction of the focus lens is determined according to a change in the evaluation value Driving direction determining means, and a focus information display means for displaying the direction in which the focus lens should be moved or the in-focus state.

  According to the imaging apparatus according to the present invention, it is possible to realize intuitively whether the operator turns the focus ring in any direction to go to the in-focus state with little cost increase.

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is an external perspective view of the digital camera according to the first embodiment. An interchangeable lens 1 is detachably attached to the front surface of a camera body 2. The interchangeable lens 1 is provided with a manual focus ring 3 that performs a focus operation during manual focus, and an AF-MF switching lever 4 that switches between an autofocus operation (AF) and a manual focus (MF) operation. The camera body 2 is provided with a release switch 5. The release switch 5 performs photometry / ranging with the first stroke (SW1) half-pressed, and records and records with the second stroke (SW2) fully pressed. It consists of a two-stage switch.

  FIG. 2 is a rear view of the digital camera. A built-in flash is provided at the upper end of the camera body 2, a plurality of input keys 6 are provided on the upper surface and the back surface of the camera body 2, and a live view display of a photographed image and playback of a recorded image are further provided on the back surface. A liquid crystal display 7 composed of an LCD for performing display or the like is provided.

  FIG. 3 shows a block circuit configuration diagram of a camera system including the interchangeable lens 1 and the camera body 2, and an image blur correction lens is also shown for reference. As a photographing optical system of the interchangeable lens 1, a focus lens 11, a zoom lens 12, an image shake correction lens 13, and a diaphragm 14 are arranged on the optical axis O.

  A lens MPU 15 is provided in the interchangeable lens 1, the output of the correction lens encoder 16 of the image blur correction lens 13, the output of the angular velocity sensor 18 via the signal processing circuit 17, and the output of the switch 19 for image blur correction on / off selection. Is connected. The lens MPU 15 is connected to a stepping motor 26 via a focus control circuit 20, a drive motor 21, a zoom encoder 22, an image blur correction circuit 23 via a linear motor 24, and an aperture control circuit 25.

  The focus lens 11 is driven via a focus control circuit 20 and a drive motor 21 by a control signal from the lens MPU 15. The focus control circuit 20 also includes a focus encoder that outputs a zone pattern signal and a pulse signal according to the movement of the focus lens 11, and the subject distance is detected by the focus encoder.

  The zoom lens 12 moves when a photographer operates a zoom operation ring (not shown), and the zoom encoder 22 outputs a zone pattern signal corresponding to the movement of the zoom lens 12. The photographic image magnification is obtained when the lens MPU 15 reads signals from the focus encoder and the zoom encoder 22 and reads out pre-stored photographic image magnification data by a combination of the subject distance and the focal length.

  The image blur correction lens 13 is driven via an image blur correction circuit 23 and a linear motor 24. In image blur correction, a shake signal of the angular velocity sensor 18 that detects rotational shake is signal-processed by the signal processing circuit 17 and input to the lens MPU 15. The lens MPU 15 calculates a correction lens drive target signal and outputs a drive signal corresponding to the difference between the correction lens drive target signal and the correction lens position signal output from the correction lens encoder 16 to the image blur correction circuit 23. Image blur correction is performed by feeding back the correction lens position signal output from the correction lens encoder 16 to the image blur correction circuit 23 in this way.

  The diaphragm 14 is driven via a diaphragm control circuit 25 and a stepping motor 26 by a control signal from the lens MPU 15.

  In the camera body 2 on the extension of the optical axis O, a quick return main mirror 31, a sub mirror 32 arranged on the back side of the quick return main mirror 31, a focal plane shutter 33, and an image pickup unit 34 by an image pickup device comprising a CCD or a MOS. Are arranged. A pentaprism 35 is provided in the reflection direction of the quick return main mirror 31, and the subject image is branched by the pentaprism 35 into a photometric means 36 and an optical viewfinder 37. A distance measuring means 38 is provided in the direction in which the light beam that has passed through the half mirror surface of the quick return main mirror 31 is reflected by the sub mirror 32.

  The output of the imaging unit 34 is connected to a video signal processing circuit 42 through a CDS circuit (double correlation sampling circuit) 39, a gain control circuit 40, and an A / D converter 41. The video signal processing circuit 42 is connected to a camera MPU 43, a buffer memory 44, a liquid crystal display 45 corresponding to the liquid crystal display 7, and a memory card 46. The camera MPU 43 is connected to the output of the operation unit 47 and the output of the distance measuring means 38. The output of the camera MPU 43 is connected to the imaging unit 34 via the focal plane shutter 33 and the timing generator 49 via the shutter drive circuit 48.

  Further, the interface circuit 51 on the interchangeable lens 1 side and the interface circuit 52 on the camera body 2 side are connected.

  The photographing light flux from the subject passes through the photographing optical system in the interchangeable lens 1 and is partially reflected by the quick return main mirror 31 whose central portion is a half mirror during preparation for photographing, and becomes an erect image at the pentaprism 35. . The photographer can confirm the erect image as a subject image in the optical viewfinder 37. Here, when an initialization operation of an image shake correction apparatus described later is performed in a state where the interchangeable lens 1 is attached to the camera body 2, the photographer visually recognizes an image variation due to the initialization operation through the optical finder 37. become.

  The photometry means 36 measures the illuminance on a not-shown focusing plate surface, and inputs the measurement result to the camera MPU 43. The camera MPU 43 determines photographing conditions such as exposure time and aperture amount. The photometric sensor in the photometric unit 36 is divided into a plurality of areas, and a photometric result for each area can be obtained.

  The sub mirror 32 arranged on the back surface of the quick return main mirror 31 causes the light beam that has passed through the half mirror surface of the quick return main mirror 31 to enter the distance measuring means 38. The distance measuring means 38 photoelectrically converts the incident light beam and performs signal processing to create distance measurement data and inputs it to the camera MPU 43.

  When the photographing operation is started, the quick return main mirror 31 and the sub mirror 32 are retracted to the pentaprism 35 side, the focal plane shutter 33 is driven by the shutter driving circuit 48, and the photographing light flux is input as a photographing optical image and is input to the imaging unit 34. The image is formed on the surface. This photographic optical image is photoelectrically converted by the imaging unit 34 into an imaging signal.

  The timing generator 49 controls the accumulation operation, readout operation, reset operation, and the like of the imaging unit 34. The CDS circuit 39 reduces accumulated charge noise of the imaging unit 34, the gain control circuit 40 amplifies the imaging signal, and the A / D converter 41 converts the amplified imaging signal from analog to digital image data.

  The video signal processing circuit 42 performs filter processing, color conversion processing, gamma processing, and the like on the image data digitized by the A / D converter 41. The image signal processed by the video signal processing circuit 42 is stored in the buffer memory 44 and displayed on the liquid crystal display 45 or recorded on the removable memory card 46.

  The operation unit 47 is a switch composed of a camera main switch, a shooting mode setting, a recording image file size setting, and a release switch 5 at the time of shooting.

  In addition to controlling the above-described operation of the camera body 2, the camera MPU 43 includes evaluation value calculation means having a function of extracting a high-frequency component in a specific region of the image signal and calculating a focus evaluation value. The camera MPU 43 communicates with the lens MPU 15 via the interface circuit 52 on the camera body 2 side and the interface circuit 51 on the interchangeable lens 1 side. In this communication, a focus drive command is transmitted to the interchangeable lens 1, and data such as the operating state of the camera body 2 and the interchangeable lens 1 and optical information is transmitted and received.

  FIG. 4 is an operation flowchart of the initial drive direction determination means by the camera MPU 43 in the first embodiment. In this routine, the driving direction to be displayed before the operator first turns the focus ring is determined, a certain direction is determined as the driving direction (step S11), and the determined driving direction is displayed on the liquid crystal display 45. (Step S12). The drive direction displayed here continues to be displayed until the next time the operator turns the focus ring, and it is unknown at this point whether the direction is the in-focus direction.

  FIG. 5 is an operation flowchart of the focus ring drive direction discriminating means. First, it is determined whether or not the focus ring has been driven (step S21). That is, after the driving direction determined by the initial driving direction determining means is displayed on the liquid crystal display 45, the process waits for the focus ring to be driven and proceeds to step S22 when driven. Whether or not the focus ring is driven may be detected by hardware using an encoder. Alternatively, the evaluation value calculated by the evaluation value calculation means may be detected by software when the evaluation value fluctuates to a predetermined value or more.

  Next, it is determined whether or not the evaluation value by the evaluation value calculation means has become higher than the previous time (step S22). If it has increased, it is determined that the direction in which the operator rotates the focus ring is in the in-focus direction. Therefore, the display drive direction is left as it is (step S23), and if it becomes lower, it is determined that the direction in which the focus ring is turned in the currently displayed drive direction is opposite to the in-focus direction, and the drive direction is changed. The display is reversed and updated (step S24). Thereafter, the determined driving direction is displayed on the liquid crystal display 45 (step S25).

  If it is determined in step S21 that the focus ring has not been driven, this process is repeated each time the focus ring is driven without performing anything. However, since the camera body 2 has already recognized the driving direction of the operator, the driving direction is displayed in the in-focus direction in the future. When the change in the evaluation value is less than a predetermined amount with respect to the drive amount, it is determined that the in-focus state has been reached and the in-focus information display is used as the in-focus mark.

  FIG. 6 is an operation flowchart from the direction determination to the display of the driving direction in the second embodiment. The second embodiment is a countermeasure when the operator mistakenly rotates the initial driving direction, or when driving without looking at the display, and the direction discriminating means is different from the first embodiment.

  A predetermined time or a predetermined number of times (hereinafter referred to as a predetermined period) is cleared (step S31). The predetermined period is a value indicating how long the direction determination shown in FIG. 5 is performed. By performing the direction determination process within a predetermined period, it corresponds to the operation of returning immediately when it is noticed that the display is erroneously turned in the opposite direction to the display. When the predetermined number of times is 1, it is the same as in the first embodiment.

  Next, it is determined whether or not a predetermined period has elapsed (step S32). At this point, since the predetermined period has been cleared in step S31, it is determined that it has not elapsed. When the predetermined period has not elapsed, direction determination is performed (step S33), which is the same as the processing from steps S21 to S24 in FIG. Therefore, only the driving direction to be displayed is determined here, and the driving direction is not yet displayed.

  It is determined whether or not the driving direction to be displayed determined in step S33 is reversed compared to the previous time (step S34). This does not determine whether the driving direction displayed on the liquid crystal display 45 is reversed, but at this time, the driving direction determined by the initial driving direction determination means remains displayed. If the driving direction is not reversed (step S34), the timer or the counter is counted up (step S35). If reversed, the timer or counter is cleared (step S36). In this way, it is possible to determine whether or not the same direction is always determined in step S33 in step S32 during the predetermined period. If it is determined that the predetermined period has elapsed, the direction determined in step S33 until that time is determined as the driving direction (step S37) and displayed on the liquid crystal display 45 (step S38).

  The next and subsequent steps are the same as in the first embodiment, and steps S21 to S25 in FIG. 5 are executed.

  The third embodiment is a form in which the timing of the initial drive direction determining means is clearly shown with respect to the first and second embodiments. The timing is the moment when the interchangeable lens 1 is attached to the camera body 2 or when the release switch 5 is half-pressed (SW1) while the interchangeable lens 1 is attached.

  FIG. 7 is an operation flowchart showing the timing of the initial drive direction determining means in the third embodiment. The initial drive direction determining means synchronizes with the timing when the release switch 5 of the operation unit 47 is turned on, the timing when the interchangeable lens 1 is attached to the camera body 2, or the setting of the drive direction display by the display method switching means.

  When an event of SW1 on, lens attachment communication, or drive direction display occurs during any processing in step S40a of the camera body 2 (step S41), initial drive direction determination means (step S42) is performed in interrupt processing.

  FIG. 8 shows a process of checking the SW1 of the release switch 5, the lens recognition flag, and the driving direction display flag between some main process in step S40b of the camera body 2 and some other process in step S40c. Step S43) is provided. When the SW1 of the release switch 5 is pressed somewhere in the main processing of steps S40a and 40c, the SW1 on flag is set. Further, when the interchangeable lens 1 is attached, a flag for recognizing the interchangeable lens 1 is set, or a flag indicating that the drive direction is being displayed is set when switching to the drive direction display setting. Next, when step S43 is passed in this loop, since any flag is set, the initial drive direction determination process of step S42 similar to the process of FIG. 4 is performed.

  In the fourth embodiment, the initial drive direction determination unit specifically determines the initial drive direction. The processing content of the initial drive direction determination means is exactly the same as in the first and second embodiments, and the timing is as in the third embodiment.

  In order to determine the initial driving direction, the following four (a) to (d) are mentioned. (A) Decide in the same direction every time. (B) Decide in a random direction. (C) The distance from the current position of the focus lens 11 to the moving end of the movable range is determined in a short direction. (D) The distance from the current position of the focus lens 11 to the moving end is determined in a long direction.

  When determining in the same direction every time in (a), it is determined to be clockwise or counterclockwise in step S11 of FIG. 4 at the timing of the third embodiment, regardless of the setting of the interchangeable lens 1 and the camera body 2. .

  FIG. 9 is a flowchart showing the operation to be replaced with step S11 when the random direction (b) is determined. First, a random number is generated (step S51). When the least significant bit of the generated random number is viewed, if 1 is determined, right rotation is determined (step S53), and if 0 is determined, left rotation is determined (step S54). . This process is merely an example of means for randomly determining which rotation, steps S53 and S54 may be reversed, and it is not necessary to determine the least significant bit of the random number. It is enough.

  FIG. 10 is an operation flowchart in the case where the distance from the current focus lens position to the moving end in (c) is determined in a shorter direction, and is processing to be replaced with step S11 in FIG. The position of the focus lens 11 is detected (step S61). Here, it is assumed that a normal interchangeable lens does not know the absolute position of the focus lens, but roughly knows where the current lens barrel is located. When the rough position of the focus lens 11 is known, it is determined whether or not the infinity side is closer (step S62). If it is close, it is determined to rotate right (step S63), and if not close, it is determined to rotate left (step S64). .

  In the case where the distance from the current position of the focus lens 11 to the moving end in (d) is determined in the long direction, the reverse of (c). That is, according to FIG. 10, if it is determined in step S62 that infinity is closer, it is determined to be left rotation (step S64), and if it is determined not to be close, it is determined to be right rotation (step S63).

  FIG. 11 shows an example of the display method of the driving direction in the fifth embodiment, and the driving direction is displayed by various methods. The processing contents of the initial drive direction determining means are exactly the same as those in the first and second embodiments, and the timing of the initial drive direction determining means is as in the third embodiment.

  When the drive direction is displayed, it may be displayed with a triangle mark as shown in (a), or may be displayed with an arrow or a character, or the rotation direction may be shown as shown in (b). it can. When it is determined that the focus is achieved, a circle at the center in the driving direction may be blinked as shown in (c), or another mark such as a cross or a square may be used.

  Furthermore, as shown in (d), the display of the size to be driven can be made in two steps to a plurality of steps according to the type, focal length, and sensitivity of the interchangeable lens 1 that can be attached. When the sensitivity is small such as when a wide-angle lens is attached or when the focal length is short, the focus lens 11 is focused more quickly by turning it slightly larger. At this time, it is preferable to display a plurality of driving directions in order to inform the operator that it is better to rotate the dial. FIG. 12 shows an example of display switching of the driving direction according to the sensitivity.

  FIG. 13 is an explanatory diagram when the driving direction in this embodiment is displayed on a part of the liquid crystal display 45. As a display method of the driving direction, the display method of FIG. Yes.

1 is an external perspective view of a camera according to Embodiment 1. FIG. It is a rear view. It is a block circuit block diagram of a camera main body and an interchangeable lens. It is an operation | movement flowchart figure of an initial drive direction determination means. It is an operation | movement flowchart figure of the drive direction discrimination | determination means of a focus ring. FIG. 6 is an operation flowchart of the second embodiment. FIG. 10 is an operation flowchart of the third embodiment. It is an operation | movement flowchart in the case of performing an initial drive direction means. FIG. 10 is an operation flowchart of the fourth embodiment. FIG. 11 is an operation flowchart when the initial drive direction is set to a distance closer to the moving end from the position of the focus lens. FIG. 10 is an explanatory diagram of a driving direction display method according to a fifth embodiment. It is explanatory drawing of the display switching of a drive direction. It is explanatory drawing when a moving direction is displayed on a display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Interchangeable lens 2 Camera body 3 Manual focus ring 4 AF-MF switching lever 5 Release switch 6 Switch 7, 45 Liquid crystal display 11 Focus lens 12 Zoom lens 13 Image stabilization lens 14 Aperture 15 Lens MPU
DESCRIPTION OF SYMBOLS 16 Correction lens encoder 18 Angular velocity sensor 23 Image blur correction circuit 34 Image pick-up part 38 Distance measuring means 42 Image | video signal processing circuit 43 Camera MPU
47 Operation unit

Claims (10)

  An image input means for obtaining an image signal of a subject via a photographing optical system, an evaluation value calculation means for calculating a focus evaluation value by extracting a high frequency component of a specific area of the image signal, and manually moving the focus lens In the imaging apparatus having the lens driving means for controlling the in-focus state, the initial driving direction determining means for determining the initial driving direction for driving the focus lens first by the lens driving means, and the initial driving direction determining means A driving direction discriminating unit that discriminates a driving direction of the focus lens according to a change in the evaluation value when the lens driving unit is driven in a direction determined by the direction, and a direction in which the focus lens should be moved or the in-focus state An imaging apparatus comprising: focus information display means for displaying a state.   The drive direction determination means performs a predetermined period or a predetermined number of determinations, and updates the display of the focus information display means only when it is determined that the direction is the same in any determination during that period. The imaging apparatus according to claim 1.   The imaging apparatus according to claim 1, wherein an interchangeable lens including the focus lens and the lens driving unit is detachable from a camera body including the image input unit and the evaluation value calculating unit.   The imaging apparatus according to claim 3, wherein the timing at which the initial drive direction determination unit determines the initial drive direction is when the interchangeable lens is attached to the camera body.   The imaging apparatus according to claim 1, wherein the timing at which the initial drive direction determining unit determines the initial drive direction is when the release switch is half-pressed.   An operator has a display switching means for selecting whether or not to display the driving direction, and the timing at which the initial driving direction determining means determines the initial driving direction is displayed by the display switching means. The imaging apparatus according to claim 1, wherein the time is selected.   The imaging apparatus according to claim 3, wherein the driving direction determining unit determines the same direction every time.   The imaging apparatus according to claim 3, wherein the initial drive direction determination unit determines a random direction.   7. The initial drive direction determining unit determines a distance from a current focus lens position to a moving end in a short direction or a long direction with respect to a movable range of the lens driving unit. The imaging device according to claim 1.   The driving direction to be displayed on the focusing information display means is one of a plurality of stages of right or left, right rotation or left rotation, in addition to being in the in-focus state. The imaging apparatus according to claim 3 or 4, wherein the steps are switched according to a type, a focal length, or a sensitivity.

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