JP2023159227A - Imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus that reduces the frequency of driving of a diaphragm 362 at the time of a live view mode.SOLUTION: A camera system 1 includes a control unit that when a first diaphragm value during an imaging unit performing imaging for recording image data is larger than a second diaphragm value during the imaging unit performing imaging for displaying an image on a display unit and a difference between the first diaphragm value and the second diaphragm value becomes larger than a first value, performs first control to change the second diaphragm value on the basis of the first diaphragm value.SELECTED DRAWING: Figure 2

Description

The present invention relates to an imaging device.

2. Description of the Related Art Cameras that display monitor images called live view images are known. Furthermore, when the brightness of the subject changes, the aperture of the photographic lens is frequently driven for exposure correction (see Patent Document 1). Therefore, there is a problem in that the brightness of the live view image screen changes due to frequent driving of the aperture.

Japanese Patent Application Publication No. 2018-33061

According to one aspect of the present invention, the imaging device includes an imaging unit that images incident light through an optical system having an aperture and outputs a signal, and an imaging unit that records image data based on the signal. The first aperture value during imaging is larger than the second aperture value during which the imaging unit performs imaging in order to display an image based on the signal on the display unit, and the first aperture value and the second aperture value are larger than the second aperture value during imaging by the imaging unit. and a control unit that performs first control to change the second aperture value based on the first aperture value when the difference between the aperture value and the aperture value becomes larger than the first value.

FIG. 1 is a perspective view illustrating a camera system. FIG. 2 is a block diagram illustrating the configuration of main parts of the camera shown in FIG. 1. FIG. FIGS. 3A to 3D are diagrams illustrating the first aperture value and the second aperture value. FIGS. 4(a) to 4(d) are diagrams for explaining the first aperture value and the second aperture value. FIGS. 5A to 5C are diagrams illustrating the first aperture value and the second aperture value. 7 is a flowchart illustrating an example of a process executed by the body-side control unit in live view mode.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a camera system 1 before an interchangeable lens 3 is attached to a camera body 2 according to an embodiment of the invention. The camera body 2 and the interchangeable lens 3 are connected by a bayonet structure of a body side mount 210 and a lens side mount 310. When the camera body 2 and the interchangeable lens 3 are combined, the terminals provided on each mount physically contact each other, and the camera body 2 and the interchangeable lens 3 are electrically connected. As will be described later with reference to FIG. 2, the camera body 2 includes an operating member 280 such as a release button and an image sensor 260.
Although FIG. 1 illustrates a camera system 1 with interchangeable lenses, the camera system 1 may be a camera or a video camera in which a camera body and a lens are integrated.

FIG. 2 is a block diagram illustrating the main configuration of the camera system 1 according to the first embodiment.
<Interchangeable lenses>
The interchangeable lens 3 includes a lens-side mount 310, a lens-side control section 330, a lens-side communication section 340, a lens-side storage section 350, a photographic lens 360, a lens drive section 370, and an aperture drive section 380.

The annular lens-side mount 310 is provided with a lens-side terminal holding portion 320 . The lens-side terminal holding section 320 has a plurality of lens-side terminals in an arc shape centered on the optical axis O. The plurality of lens side terminals include, for example, a mounting detection terminal that indicates to the camera body 2 that the interchangeable lens 3 is attached to the camera body 2, and a terminal used for communication between the interchangeable lens 3 and the camera body 2. This includes a plurality of communication terminals for communication, a power supply terminal for supplying power from the camera body 2 to the interchangeable lens 3, a ground terminal, and the like.

The lens side control section 330 is composed of a microcomputer, its peripheral circuits, and the like. The lens-side control section 330 executes a control program stored in the lens-side storage section 350 to control each section of the interchangeable lens 3. The lens-side control section 330 is connected to a lens-side communication section 340, a lens-side storage section 350, a lens drive section 370, and an aperture drive section 380.

The lens-side communication unit 340 performs predetermined communication with the body-side communication unit 240 when the interchangeable lens 3 is attached to the camera body 2. The lens-side communication section 340 is connected to the lens-side control section 330 and the above-mentioned lens-side terminal. Communication performed between the lens side communication section 340 and the body side communication section 240 via the lens side terminal and body side terminal that are in contact allows the lens control section 330 to issue instructions such as movement of the lens 361, etc., which will be described later. It will be done. Further, a transmission request is sent from the camera body 2 to the lens control section 330 of the interchangeable lens 3 to transmit information in the interchangeable lens 3, such as information indicating the state of the lens drive section 370, to the camera body 2.

The information indicating the state of the lens driving section 370 described above is, for example, information indicating the state in which the lens driving section 370 is driving the lens 361. On the other hand, data indicating the position of the lens 361 after movement, the state of the drive unit in the interchangeable lens 3, data read from the lens side storage section 350, information regarding the shooting distance and shooting magnification, etc. are stored in the interchangeable lens 3. The information is sent to the camera body 2 as information.

The lens side storage section 350 is configured by a nonvolatile storage medium. Recording and reading of data in the lens side storage section 350 is controlled by the lens side control section 330. In addition to storing control programs executed by the lens side control unit 330, the lens side storage unit 350 also stores data indicating the model name of the interchangeable lens 3 (also referred to as model name information), and the focal length and aberration of the photographic lens 360. Stores data indicating optical characteristics such as information. Note that the data stored in the lens storage unit 350 may include an error tolerance value based on the difference in optical characteristics between the first aperture value and the second aperture value, which will be described in detail later.

The photographing lens 360 guides subject light to the imaging surface of the image sensor 260 of the camera body 2 . The optical axis O of the photographic lens 360 coincides with the centers of the lens side mount 310 and the body side mount 210. The photographing lens 360 includes a plurality of lenses 361 including a focusing lens and a zoom lens, and an aperture 362. Although the lens 361 has a plurality of lenses, it is simplified and illustrated as one lens in FIG. 2. At least a portion of the photographic lens 360 is configured to be able to move forward and backward in the direction of the optical axis O by a lens drive unit 370 or manual operation.
For example, the focusing lens is configured to be able to move forward and backward in the direction of the optical axis O by the lens driving section 370. By moving the focusing lens, the focal position of the photographing lens 360 is adjusted.

The diaphragm 362 is a so-called aperture diaphragm having a plurality of diaphragm blades, and by driving the diaphragm blades, changes the aperture diameter (aperture value) of the photographing lens 360 and adjusts the amount of light incident on the image sensor 260. The aperture drive section 380 drives the aperture blades to change the aperture diameter (aperture value). The aperture drive section 380 is composed of a stepping motor and an aperture drive mechanism. The aperture drive unit 380 drives the aperture blades of the aperture 362 to change the aperture diameter based on instructions from the lens-side control unit 330. Further, the aperture drive section 380 detects the aperture value of the aperture 362 by measuring the amount of drive of the aperture blades using an encoder provided near the aperture blades or a pulse counter.

The lens drive section 370 is configured by a lens drive mechanism including a stepping motor. The lens drive section 370 moves the focusing lens forming the lens 361 along the direction of the optical axis O in response to a drive signal output from the lens side control section 330. The direction, amount, and speed of movement of the focusing lens are instructed, for example, from the body-side control unit 230. The lens driving section 370 detects the position of the focusing lens using an encoder provided near the lens or driving steps of a stepping motor.

<Camera body>
The camera body 2 includes a body-side mount 210, a body-side control section 230, a body-side communication section 240, a power supply section 250, an image sensor 260, a signal processing section 270, an operation member 280, and a display section 290. Further, the recording unit 100 is configured to be detachable from the camera body 2.

The annular body-side mount 210 is provided with a body-side terminal holding portion 220 . The body-side terminal holding section 220 has a plurality of body-side terminals. The plurality of body-side terminals include, for example, a mounting detection terminal that informs that the interchangeable lens 3 is mounted, a plurality of communication terminals used for communication between the camera body 2 and the interchangeable lens 3, and the camera body 2. It includes a power supply terminal through which power is supplied from to the interchangeable lens 3 and a ground terminal.

The body-side control section 230 has a storage section 235, and is composed of a microcomputer, its peripheral circuits, and the like. The body-side control section 230 executes a control program stored in the storage section 235 to control each section within the camera body 2. The body-side control section 230 is connected to the body-side communication section 240, the power supply section 250, the image sensor 260, the signal processing section 270, the operation member 280, the display section 290, the recording unit 100, and the above-mentioned attachment detection terminal.

Recording and reading of data in the storage section 235 provided in the body-side control section 230 is controlled by the body-side control section 230 . In addition to storing control programs executed by the body-side control unit 230, the storage unit 235 also stores model name information of the interchangeable lens 3, data indicating optical characteristics of the interchangeable lens 3, etc. received by the body-side communication unit 240. Can be memorized.

The body-side communication unit 240 performs the above-described communication with the lens-side communication unit 340 when the interchangeable lens 3 is attached to the camera body 2. The body-side communication section 240 is connected to the body-side control section 230 and the communication terminal described above.
The power supply unit 250 converts the voltage of a battery (not shown) into a voltage used in each part of the camera system 1 and supplies it to each part of the camera body 2 and the interchangeable lens 3. The power supply unit 250 can switch power supply on and off for each power supply destination according to instructions from the body-side control unit 230. The power supply section 250 is connected to the body-side control section 230 and the above-mentioned power supply terminal.

The image sensor 260 is a solid-state image sensor, such as a CMOS image sensor or a CCD image sensor, in which pixels are two-dimensionally arranged in the row and column directions. The image sensor 260 captures a subject image on an imaging surface and outputs an image signal based on a control signal from the body-side control unit 230. The image sensor 260 is connected to the body-side control section 230 and the signal processing section 270.

The image sensor 260 includes pixels for image generation (referred to as imaging pixels) and pixels for focus detection (referred to as focus detection pixels) arranged on the imaging surface. A signal generated by the imaging pixel (hereinafter referred to as an imaging pixel signal) is used by a signal processing unit 270, which will be described later, to generate image data. In addition, the signal generated by the focus detection pixel (hereinafter referred to as focus detection pixel signal) is processed by the signal processing unit 270 (described later) to determine the imaging state of the image formed by the interchangeable lens 3 on the imaging surface of the image sensor 260, in other words, as described below. This is used in focus detection processing to detect the amount of defocus.
Note that the image sensor 260 may be provided with a pixel that has a plurality of photoelectric conversion units and outputs a signal that can be used for both imaging and focus detection.

The signal processing unit 270 performs predetermined image processing on the imaging pixel signal output from the imaging pixel of the image sensor 260 to generate image data. The generated image data is recorded in the recording unit 100 in a predetermined file format, or used for image display on the display section 290. The signal processing section 270 is connected to the body-side control section 230, the image sensor 260, and the display section 290.

Further, the signal processing unit 270 uses the focus detection pixel signal output from the focus detection pixel of the image sensor 260 to calculate the defocus amount of the interchangeable lens 3 using a phase difference detection method. The amount of defocus is the amount of deviation between the position of the image of the subject formed by the interchangeable lens 3 (imaging plane) and the position of the imaging plane of the image sensor 260. Based on the calculated defocus amount, the signal processing unit 270 moves the focusing lens to the in-focus position, which is the position of the focusing lens when an image of a specific subject is formed on the imaging surface of the image sensor 260 by the interchangeable lens 3. Calculate the amount of movement.

The body-side control section 230 also functions as a photometry calculation section. The body-side control unit 230 detects brightness information (Bv value) of the subject based on the imaging pixel signal input from the image sensor 260 to the signal processing unit 270. The body-side control unit 230 controls the aperture value (Av value), shutter speed (Tv value), and photographing sensitivity (Sv value) based on the Bv value and information on the program diagram stored in the storage unit 235. Determine. The photographing sensitivity is also called ISO sensitivity, and is the gain during photoelectric conversion in the image sensor 260. Note that the Av value, Tv value, and Sv value are values each calculated by Apex calculation according to the shooting mode.

The recording unit 100 is a memory card that is a non-volatile storage medium. The recording unit 100 is attached to an insertion portion (not shown) provided inside the exterior surface of the camera body 2 . Recording and reading of image data in the recording unit 100 is controlled by a body-side control section 230.

An operation member 280 including a release button, various operation switches, etc. is provided on the exterior surface of the camera body 2. By operating the operating member 280, the user performs settings such as a shooting mode and a live view mode to be described later.
Setting the shooting mode means setting whether the image to be shot is a still image or a moving image, whether the above-mentioned Av value, Tv value, and Sv value are all determined automatically by the camera, or whether the above-mentioned Av value, Settings include whether the user himself/herself determines part or all of the Tv value and Sv value.
The release button has two pressing operations: half-press and full-press. When the full press operation is performed, an instruction to capture an image is given to the body-side control unit 230, and an image captured by the image sensor 260 and generated by the signal processing unit 270 is stored in the recording unit 100. The half-press operation is a press-down operation to about half the amount of press when fully pressed, and a photographing preparation operation is performed.

The display section 290 includes, for example, an organic EL or liquid crystal display panel. The display unit 290 displays an image based on the image data processed by the signal processing unit 270, an operation menu screen, etc. in accordance with instructions from the body-side control unit 230. Display section 290 is connected to body-side control section 230 and signal processing section 270.
Furthermore, the display unit 290 is also capable of displaying a so-called live view image in which image data based on signals repeatedly captured by the image sensor 260 is displayed dynamically and sequentially. This live view image display may have lower image quality than the image generated by imaging by fully pressing the release button.
Live view image display is performed while the camera system 1 is powered on in a shooting mode other than playback mode or setting mode.
In this embodiment, the following three live view modes are provided for displaying a live view image, and any one of the live view modes is selectable.

The first live view mode is a display of a live view image that emphasizes the visibility of the displayed image without reflecting various user settings at the time of shooting. The first live view mode is a mode in which live view image generation and exposure calculation are performed based on the imaging pixel signal, and focus detection processing and the like are performed based on the focus detection pixel signal.
Various user settings during shooting include settings such as shutter speed, aperture value, and exposure to obtain the user's desired image effect. When the aperture value is set to a large value (the aperture aperture is narrowed down), in the first live view mode, a bright image is displayed in order to emphasize the ease of viewing the live view image without narrowing down the aperture to the set aperture value. In other words, in the first live view mode, the aperture can only be adjusted up to a predetermined value (the second aperture value for live view, which will be described later) that allows accurate distance measurement calculations from the imaging signal that generates the live view image. Don't narrow it down. This first live view mode is a mode in which a live view image to be displayed is displayed as close as possible to an optical viewfinder (so-called OVF). Therefore, in the first live view mode, even if the user has set exposure compensation, the live view image is displayed without considering the exposure compensation set by the user. More specifically, even if the user sets -1/3 stop exposure compensation, the image displayed in live view will not be a dark image.

The second live view mode is a display of a live view image that reflects various settings made by the user at the time of actual shooting. Similar to the first live view mode, this is a mode in which live view image generation and exposure calculations are performed based on the imaging pixel signal, and focus detection processing and the like are performed based on the focus detection pixel signal. In the second live view mode, the exposure during actual shooting is simulated based on the settings during actual shooting, and an image is displayed on the display unit 290. However, in order to enable distance measurement calculations from the imaging signal that generated the live view image, the aperture value is narrowed down only to a predetermined value that allows distance measurement (a live view aperture value that is a second aperture value to be described later). The image displayed as a live view image is made into a dark image by image processing. As mentioned above, the first live view mode does not necessarily reflect the user's settings, but in the second live view mode, for example, if the user has set exposure compensation, the live view image will reflect the user's settings. Displays the exposure compensation that has been set. More specifically, if the user has set the exposure correction to -1/3 stop, the image displayed in live view will be 1/3 step darker.

The third live view mode is a mode in which all user settings are reflected in the displayed live view image. In the third live view mode, various calculations for actual shooting are not performed. In the third live view mode, if the aperture value is set to a large value during actual shooting, the aperture value is stopped down to the set aperture value and an image is taken. As a result, the image displayed in live view will be dark, but you can check the depth of field at the set aperture value and preview the actual shooting.

In the present embodiment, in the camera system 1 described above, when the live view mode is either the first or second live view mode, the live view image is displayed on the display unit 290, and the imaging pixel signal and Based on the focus detection pixel signal, the body-side control unit 230 performs exposure calculations, defocus amount calculations, and the like. This exposure calculation and defocus amount calculation are repeatedly performed during live view display. The calculated exposure calculation results are used for various settings for subsequent imaging for live view images and for imaging by pressing the release button. The defocus amount calculated while displaying the live view image is used to instruct the driving of the focusing lens when the release button is pressed halfway. In the following, a case will be described in which the aperture value at the time of photographing is automatically determined by the body-side control section 230 from the exposure calculation result by setting the operation section. That is, the photographing mode is set to a program automatic exposure calculation mode, a shutter speed priority exposure calculation mode, or a full auto mode in which sensitivity setting is also performed by calculation.

<Two aperture values>
The body-side control unit 230 sets two aperture values. The first aperture value is the first aperture value (also referred to as the photographing aperture value) that is applied when the release button constituting the operation member 280 is pressed down (fully pressed) to take an image (actual photographing), and is as described above. This is a value based on apex exposure calculation.

The second aperture value will be described in detail later with reference to FIGS. 3 to 5, but the second aperture value is the second aperture value that is applied during image capture to display a live view image on the display unit 290, that is, to the exposure calculation and defocus amount calculation. (also referred to as live view aperture value).
It is better for the second aperture value to be smaller than the first aperture value (the aperture is open). This is because when the aperture value of the aperture 362 of the photographic lens 360 changes, the depth of focus of the subject image (tolerable width for distance measurement) changes. When the aperture value of the aperture 362 is small (the aperture is opened), the depth of focus is shallow, and when the aperture value is large (the aperture is closed), the depth of focus is deep. Therefore, if the defocus amount is calculated using an aperture value (closed down) that is larger than the aperture value set for actual shooting, an accurate value cannot be calculated. In addition, since the best image plane due to the aberration of the photographing lens 360 changes depending on the aperture value, the aperture (second aperture value) when calculating the defocus amount is the aperture value at the time of shooting (the first aperture value). It is even better if it is the same as
The first aperture value is changed by exposure calculation in accordance with changes in the brightness of the subject. However, if the brightness of the subject changes frequently and you drive the aperture blades by frequently changing the second aperture value during live view display in accordance with the changes in the first aperture value, the aperture drive The sound (driving sound) generated by the section 380 is likely to become a problem. Furthermore, flickering of the live view image due to sudden changes in the brightness of the image displayed on the display unit 290 tends to become a problem.

The body-side control unit 230 according to the present embodiment calculates control values including the first aperture value based on the photometric value in the live view mode, and stores each calculated value in the storage unit 235. . The body-side control unit 230 instructs the aperture drive unit 380 to drive the aperture 362 to the first aperture value stored in the storage unit 235 when the release button is fully pressed. Take pictures and obtain images for recording.

Furthermore, in this embodiment, the body-side control unit 230 sets the first aperture value so that the aperture 362 is not driven frequently when capturing a live view image even if the brightness of the subject changes frequently. A second aperture value that changes less than the change in is calculated. During live view display, the aperture 362 is driven to the second aperture value to obtain a live view image.

Upon acquiring the live view image, the body-side control unit 230 recalculates the control values including the first aperture value based on the new photometric values, and updates and stores each calculated value in the storage unit 235. The body-side control unit 230 also recalculates the second aperture value, and updates and stores the calculated value in the storage unit 235. If the release button is not pressed down (fully pressed), the body-side control unit 230 drives the aperture 362 so that the aperture value of the aperture 362 becomes the second aperture value stored in the storage unit 235. , to obtain a live view image.

<Calculation of first and second aperture values>
The calculation of the first aperture value and the second aperture value in the live view mode will be described in more detail.
FIGS. 3A to 3D are diagrams illustrating the first aperture value and the second aperture value. The upper line indicates the first aperture value (photographing aperture value), and the lower line indicates the second aperture value (live view aperture value). The units of the first aperture value and the second aperture value are each an exposure calculation value (apex calculation value), and the aperture value on the open side is indicated as Av1, and the aperture value on the small diameter side is displayed up to Av6. The aperture value and minimum value of the aperture 362 may be changed as appropriate for each model of the interchangeable lens 3, for example. The first aperture value and the second aperture value calculated by the body-side control unit 230 are represented by the position of a triangle (▽) on each line.
In the example of FIG. 3A, the calculated first aperture value (photographing aperture value) is Av4, and the second aperture value (live view aperture value) is Av3.5.

The body-side control unit 230 controls the storage of the image sensor 260 in synchronization with the frame rate of live view display, for example. Then, as described above, the Bv value is determined based on the signal value (also referred to as photometric value) of the imaging pixel signal generated by the imaging pixel of the image sensor 260 through accumulation. Furthermore, based on the Bv value and information on the program diagram stored in the storage unit 235, the first aperture value (Av value), shutter speed (Tv value), and sensitivity (Sv value) are determined. The first aperture value (Av value), shutter speed (Tv value), and sensitivity (Sv value) are stored in the storage unit 235 as control values.
The body-side control unit 230 calculates the control values including the first aperture value (Av value) every time the imaging pixel signal of the image sensor 260 is input to the signal processing unit 270. The control value is updated and recorded in the storage unit 235.

When the first aperture value (Av value) is calculated for the first time in the live view mode, the body side control unit 230 sets the allowable range of the apex value by one stop to the open side from the first aperture value (Av value). (displayed by a dashed rectangle). As described above, since the control unit 230 calculates the defocus amount based on the focus detection pixel signal of the live view image, the depth of focus of the subject image is shallower than the first aperture value set for shooting. Set the aperture value as the second aperture value. In this embodiment, the range between the first aperture value itself and one step open side of the first aperture value is set as the range for setting the second aperture value, and this is referred to as the tolerance range. There is. Then, the initial second aperture value (Av value) is determined to be an intermediate value within the allowable range (an aperture value 1/2 stop from the open side). In the example of FIG. 3(a), the first aperture value (photographing aperture value) is Av4, so the second aperture value (live view aperture value) is one stop between Av4 and Av3 on the open side. The value is determined to be Av3.5.
Note that, although the allowable range is exemplified as one step on the open side in terms of the apex value, it is not limited to one step, and may be two steps or 0.5 steps on the open side. Alternatively, the upper limit (smaller diameter side) and lower limit (opener side) of the allowable range may be made different depending on the information of the interchangeable lens 3 (focal length, open aperture value, etc.).
We will also explain an example in which the middle value of the allowable range is determined as the second aperture value (Av value), but we will also explain a value that is not exactly the middle value of the range (for example, 1/3 stop or 5/6 stop from the open side). ) may be used as the second aperture value (Av value).

FIG. 3(b) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes brighter than in the state of FIG. 3(a). As explained in FIG. 3(a), the body-side control unit 230 determines the first aperture value (Av value).

In the state of FIG. 3(b), the first aperture value (photographing aperture value) is changed to the smaller diameter side (larger Av value) than in the state of FIG. 3(a), and the first aperture value is Av4. 4, and accordingly, the permissible range of the second aperture value based on the first aperture value (indicated by a broken rectangle) also moves toward the smaller diameter side. The body-side control unit 230 determines whether the second aperture value (Av value) previously determined in the state shown in FIG. ). The Av3.5 set last time (Fig. 3(a)) is within the allowable range for one stop this time (Av3.4 to 4.4), so the second aperture value (Av (value) remains at Av3.5 without changing it. By maintaining the second aperture value (Av value), the frequency of driving the aperture 362 during live view mode can be suppressed.

FIG. 3(c) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even brighter than in the state of FIG. 3(b). The body-side control unit 230 determines the first aperture value (Av value).

In the state of FIG. 3(c), the first aperture value (Av value) is changed to the smaller diameter side than in the state of FIG. 3(b), and the first aperture value is Av4.8. The allowable range of the second aperture value based on the value (indicated by a broken rectangle) also moves toward the smaller diameter side. The body-side control unit 230 changes the maintained second aperture value (dotted line triangle Av3.5) in FIG. The second aperture value (Av value) is changed to the smaller diameter side because it is outside the permissible value range (Av3.8 to 4.8 indicated by the broken rectangle in FIG. 3(c)). Av4.3 (indicated by a solid triangle), which is the intermediate value of the second aperture value tolerance range (Av3.8 to Av4.8) calculated this time, is determined as the second aperture value (Av value).

FIG. 3(d) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even brighter than in the state of FIG. 3(c). The body-side control unit 230 determines the first aperture value (Av value).

In the state of FIG. 3(d), the first aperture value (Av value) is changed to the smaller diameter side than in the state of FIG. 3(c), the first aperture value is Av5.8, and the first aperture value is Av5.8. The allowable range of the second aperture value based on the value (indicated by a broken rectangle) also moves toward the smaller diameter side. The body-side control unit 230 determines whether the second aperture value (Av value) in FIG. Since it falls outside the permissible range (indicated by the dashed rectangle in Figure 3(d)) of Av4.8 to 5.8, the second aperture value (Av value) is changed to the small diameter side, and the intermediate value of the newly imagined range is set. An attempt is made to determine the second aperture value (Av value).

However, in this embodiment, the small diameter side of the second aperture value (Av value) is limited to Av5. The reason why a limit value is provided on the small diameter side of the second aperture value (Av value) is that the smaller the aperture diameter of the aperture 362, the lower the detection accuracy of the above-mentioned image shift amount (phase difference). Since a decrease in phase difference detection accuracy leads to a decrease in focus detection accuracy, in this embodiment, a limit value is provided on the small diameter side of the second aperture value (Av value) (Av5 in this example), so that live This suppresses the decline in focus detection accuracy in view mode.
Therefore, in FIG. 3(d), where the brightness of the subject is even brighter than in the state of FIG. 3(c), the allowable range of the second aperture value is Av4.8 to Av5.8, as shown by the dashed rectangle. The intermediate value is Av5.3, but the second aperture value that is actually set is the limit value Av5 on the small diameter side shown by the black triangle (▼).
Note that the limit value of the second aperture value (Av value) on the small diameter side may be changed as appropriate for each model of the interchangeable lens 3, for example.

FIG. 4(a) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even brighter than in the state of FIG. 3(d). The body-side control unit 230 determines the first aperture value (Av value).

In the state of FIG. 4(a), the first aperture value (Av value) is changed to the smaller diameter side than in the state of FIG. 3(d), the first aperture value is Av6.8, and the first aperture value is Av6.8. The allowable range of the second aperture value based on the value (indicated by a broken rectangle) also moves toward the smaller diameter side. The body-side control unit 230 determines that the second aperture value (Av5) that is being maintained is within the permissible range of the second aperture value based on the first aperture value calculated this time (indicated by the dashed rectangle in FIG. 4(a)). Although the second aperture value (Av value) deviates from Av5.8 to Av6.8, it is maintained at Av5, which is the limit value on the small diameter side of the second aperture value (Av value). Even if the brightness of the subject becomes even brighter than the state in Figure 3(d), the second aperture value in Figure 4(a) is the limit value on the small diameter side shown by the black triangle (▼). It remains Av5.

By the way, if the second aperture value (Av value) is limited on the small diameter side, there is a possibility that the live view image displayed on the display section 290 will become bright (an overexposed state). In the first live view mode described above, in order to suppress such changes in the brightness of the display screen, the body-side control unit 230 shortens the exposure time (storage time, Tv value) of the image sensor 260, and adjusts the sensitivity. (Sv value) may be lowered. Such control makes it possible to suppress changes in the brightness of the live view image displayed on the display unit 290. As mentioned above, in the first live view mode, the user's settings (exposure compensation, etc.) are not reflected in the process of suppressing changes in the brightness of the display screen, but in the second live view mode, the user's settings (exposure compensation, etc.) are not reflected. The exposure time (storage time, Tv value) and sensitivity (Sv value) are determined by considering the settings (exposure compensation, etc.).

FIG. 4(b) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes darker than in the state of FIG. 4(a).

In the state of FIG. 4(b), the first aperture value (Av value) is changed to the open side compared to the state of FIG. 4(a), and the first aperture value is Av6. In line with this, the allowable range of the second aperture value based on the first aperture value (indicated by a broken rectangle) also moves toward the open side. The body-side control unit 230 changes the Av5 that was previously set and maintained in FIG. 4(a) to the allowable range of the second aperture value based on the first aperture value calculated this time (indicated by the broken line rectangle in FIG. 4(b)). Av5 to 6), and the intermediate value Av5.5 of the allowable range is on the smaller diameter side than the limit value (Av5), so the second aperture value (Av value) is maintained at the limit value Av5. do. In FIG. 4B, a black triangle (▼) indicates that the second aperture value is maintained at the limit value Av5 on the small diameter side.

FIG. 4(c) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even darker than the state of FIG. 4(b).

In the state of FIG. 4(c), the first aperture value (Av value) is changed to the open side compared to the state of FIG. 4(b), and the first aperture value is Av4.8. Since the first aperture value (Av value) has been changed to the open side, the allowable range of the second aperture value based on the first aperture value (indicated by a broken rectangle) also moves to the open side. The body-side control unit 230 determines that the second aperture value (Av value) in FIGS. 4(a) and 4(b), which is maintained at the small diameter limit value Av5 indicated by the dotted triangle, is the second If the second aperture value is outside the allowable range of Av3.8 to Av4.8 (indicated by the broken rectangle in Fig. 4(c)) based on the aperture value of 1, the second aperture value (Av value) should be set to the open side. Change to In the state of FIG. 4(c), the intermediate value Av4.3 of the allowable range (Av3.8 to 4.8) of the second aperture value based on the first aperture value Av5 calculated this time (the solid line in FIG. 4(c) triangle) is determined as the second aperture value (Av value).

FIG. 4(d) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even darker than the state of FIG. 4(c).

In the state of FIG. 4(d), the first aperture value (Av value) is Av4.5, which is changed to the open side compared to the state of FIG. 4(c), and the second aperture value is based on the first aperture value. The value tolerance (indicated by a dashed rectangle) also moves to the open side. The body-side control unit 230 determines that the second aperture value Av4.3 in FIG. 4(c) determined during the previous calculation is within the allowable range of the second aperture value based on the first aperture value calculated this time (FIG. 4(c)). (represented by the dashed rectangle in d)) is included in Av3.5 to Av4.5, so the second aperture value Av4.3 in FIG. 4(c) determined during the previous calculation is maintained without being changed. By maintaining the second aperture value (Av value), the frequency of driving the aperture 362 during live view mode can be suppressed.

FIG. 5(a) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even darker than the state of FIG. 4(d).

In the state of FIG. 5(a), the first aperture value (Av value) is changed to the open side compared to the state of FIG. 4(b), and the first aperture value is Av2.5. The body-side control unit 230 changes the current second aperture value (Av4.3 shown by a broken triangle in FIG. 5A) to the calculated first aperture value (Av2.5 in FIG. 5A). If it is larger than , the second aperture value is changed to the first aperture value without comparing the current second aperture value (Av value) with the allowable range of the second aperture value based on the first aperture value. Although the above is repeated, since the control unit 230 calculates the defocus amount based on the focus detection pixel signal of the live view image, the first value set for shooting is The second aperture value is set to an aperture value with a depth of focus of the subject image that is shallower than the aperture value.Therefore, the newly calculated first aperture value Av2.5 becomes the maintained second aperture value Av4. 3, so the middle value (Av2) of the allowable range (Av1.5 to 2.5) of the second aperture value based on the first aperture value calculated this time is set to the second aperture value (Av value).

FIG. 5(b) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even darker than the state shown in FIG. 5(a).

In the state of FIG. 5(b), the first aperture value (Av value) is changed to the open side compared to the state of FIG. 5(a), and the first aperture value is Av2.2. In accordance with this, the allowable range of the second aperture value based on the first aperture value (indicated by a broken rectangle) also moves toward the open side. The body-side control unit 230 determines that the second aperture value Av2 in FIG. 5(a) determined during the previous calculation is within the allowable range of the second aperture value Av1.2 to 2.2. 2 (indicated by the dashed rectangle in FIG. 5(b)), the second aperture value Av2 in FIG. 5(a) determined during the previous calculation is maintained unchanged. By maintaining the second aperture value (Av value), the frequency of driving the aperture 362 during live view mode can be suppressed.

FIG. 5(c) is a diagram illustrating the first aperture value and the second aperture value when the brightness of the subject becomes even darker than the state shown in FIG. 5(b). In the state of FIG. 5(c), the first aperture value (Av value) is changed to Av2 on the open side compared to the state of FIG. It moves and becomes Av1-2.

In this embodiment, it is assumed that the upper limit of opening of the aperture 362 is Av2. That is, the open aperture value of the interchangeable lens 3 is Av2 (F value is 2). When the first aperture value (Av value) calculated based on the Bv value and the information of the program diagram stored in the storage unit 235 is on the open side than the upper limit value of the aperture, the body side control unit 230 maintains the first aperture value (Av value) at the open value. Further, when the first aperture value (Av value) is set to the open value, the second aperture value (Av value) is also set to the same open value as the first aperture value (Av value). In FIG. 5(c), a black triangle (▼) indicates an open value.

As explained above, in this embodiment, in order to reduce the frequency of driving the aperture 362 in the live view mode, the second aperture value, which is the live view aperture value, is set to the first aperture value, which is the photography aperture value. The second aperture value (Av value) is always set to the open side than the aperture value, and the second aperture value (Av value) is controlled so as not to be changed as much as possible even if the brightness of the subject changes.

<Explanation of flowchart>
An example of a process executed by the body-side control unit 230 when the above-described live view mode is either the first or second live view mode will be described with reference to the flowchart of FIG. 6. The body-side control unit 230 is activated, for example, when the main switch is turned on, or when no operation continues for a predetermined period of time, it enters a sleep operation, but the sleep operation is canceled by operating the operating member 280. Then, the process according to the flowchart of FIG. 6 is started. Canceling the sleep operation (returning to the normal state) is performed when a switch or the like constituting the operating member 280 is operated. The operation may be, for example, a half-press operation on the release button. FIG. 6 explains the process of displaying live view when the power is turned on or the sleep operation is canceled, and the live view display is repeatedly performed until the release button is fully pressed.

In step S10, the body-side control unit 230 controls the exposure setting in the live view mode to a predetermined value (initial value), and performs accumulation control on the image sensor 260. For example, instruct the interchangeable lens 3 to drive the aperture 362 to a predetermined initial value (corresponding to the second aperture value), and set the accumulation time and sensitivity of the image sensor 260 during live view imaging to the predetermined initial values. control to perform an accumulation operation for capturing the first live view image.

In step S20, the body-side control unit 230 causes the signal processing unit 270 to read a signal from the image sensor 260, and the process proceeds to step S30. The body-side control unit 230 calculates the first aperture value (photographing aperture value) and the second aperture value (live view aperture value) as described above by performing exposure calculation in step S30. That is, the body-side control unit 230 detects the brightness information (Bv value) of the subject based on the imaging pixel signal input to the signal processing unit 270, and uses the Bv value and the program stored in the storage unit 235. Based on the information on the diagram, the photographing aperture value (first aperture value, Av value), shutter speed (Tv value), and sensitivity (Sv value) are determined. Further, the body-side control unit 230 calculates an allowable range of the second aperture value separately from the first aperture value. Each control value including the calculated allowable range of the first aperture value and the second aperture value is stored in the storage unit 235.

Further, in step S30, the body-side control unit 230 also calculates the amount of defocus. The body-side control unit 230 causes the signal processing unit 270 to calculate the defocus amount as described above using the signal output from the focus detection pixel of the image sensor 260.
In this embodiment, the defocus amount is calculated in step S30, but the focusing lens is not driven yet at this point.

In step S40, the body-side control unit 230 sets the aperture 362 to the second aperture value (aperture value for live view) as described using FIGS. 3 to 5, and then performs live view display. The body-side control unit 230 causes the signal processing unit 270 to generate a live view image using the imaging pixel signal output from the image sensor 260, and causes the display unit 290 to display the generated live view image.

In step S50, the body-side control unit 230 determines whether the release button has been pressed halfway. The body-side control unit 230 makes an affirmative determination in step S50 when the release button is pressed halfway and proceeds to step S60, and returns to step S10 when the release button is not pressed halfway.

In step S60, the body-side control unit 230 moves the focusing lens constituting the lens 361 to the interchangeable lens 3 along the direction of the optical axis O based on the defocus amount calculated in step S30 by the signal processing unit 270. move it. That is, the lens-side control unit 330 instructs the lens drive unit 370 to drive the focusing lens, and performs a focusing drive operation. After that, the process advances to step S70.

In step S70, the body-side control unit 230 determines whether the release button has been fully pressed. The body-side control unit 230 makes an affirmative decision in step S70 when the release button is pressed fully and proceeds to step S80, and makes a negative decision in step S70 when the release button is not pressed fully and returns to step S10.

After returning to step S10, the body-side control unit 230 again performs the processing from step S10 onwards. Exposure settings for the second and subsequent frames in live view mode are based on the second aperture value stored in the storage section 235, the shutter speed (Tv value) and sensitivity (Sv value) stored in the storage section 235. Use. Here, it is assumed that at least one of the shutter speed (Tv value) and sensitivity (Sv value) stored in the storage unit 235 may be corrected. The reason for this is that, as described above, the brightness of the live view image displayed on the display unit 290 may change as the brightness of the subject changes, so the shutter speed (Tv value) and sensitivity (Sv value) This is to adjust the brightness of the displayed live view image by correcting.

In step S80, which proceeds when the release button is fully pressed (affirmative determination in step S70), the body-side control unit 230 performs an accumulation operation to capture an image for recording. At that time, the aperture 362 stored in the storage unit 235 is set to the first aperture value (aperture value for photographing, Av value), and the shutter speed calculated by the apex calculation and stored in the storage unit 235 ( The storage control of the image sensor 260 is performed using the Tv value), and the sensitivity (Sv value), which is also calculated by Apex calculation and stored in the storage unit 235, is processed.

In step S90, the body-side control unit 230 reads the signal from the image sensor 260 to the signal processing unit 270, and proceeds to step S100. In step S100, the body-side control unit 230 causes the signal processing unit 270 to perform predetermined image processing on the imaging pixel signal output from the image sensor 260 to generate an image for recording. Thereby, the signal processing unit 270 performs predetermined image processing to generate an image for recording.

In step S110, the body-side control unit 230 displays an image. That is, body-side control section 230 causes display section 290 to display the image processed by signal processing section 270 in step S100.
In step S120, the body-side control section 230 causes the recording unit 100 to record the file of the image processed by the signal processing section 270.

In step S130, the body-side control unit 230 determines whether the live view mode has ended. When the live view mode ends, the body-side control unit 230 makes an affirmative determination in step S130 and ends the process shown in FIG. 6. If the live view mode does not end, a negative determination is made in step S130 and the process returns to step S10.
Here, when the live view mode ends, it means that the power is turned off, a menu is displayed on the display unit 290 by user operation, or there is no need to display live view due to a transition to sleep operation, etc. That's true.

Note that the display processing (S100) and recording processing (S110) in FIG. 6 may be performed in the same order or in parallel.
Further, in this embodiment, the defocus amount is calculated in step S30, and after a half-press operation is performed in step S50, the focusing lens is driven in step S60. A focusing lens may also be driven.

In either the first or second live view mode of the embodiment described above, the following effects can be obtained.
(1) A camera system (camera system 1) consisting of a camera body 2 and an interchangeable lens 3 equipped with an aperture 362 is a body that calculates a first aperture value, which is an aperture value for photographing, based on a photometric value. The camera includes a side control unit 230 and a body side control unit 230 that sets a second aperture value, which is a live view aperture value, within an allowable aperture value range based on the first aperture value. With this configuration, even if the first aperture value changes due to a change in the brightness of the subject, as long as the second aperture value is set within the permissible aperture range, the changed first aperture value will change. To maintain a set second aperture value without immediately changing it in conjunction with the value. This prevents the diaphragm 362 from being driven frequently during the live view mode, and reduces driving noise. Furthermore, since the aperture change frequency is reduced, the durability of the lens aperture mechanism can be improved (durable wear can be suppressed). Suppressing the driving of the aperture 362 during the live view mode is also suitable in terms of suppressing flickering on the screen of the display unit 290 that displays the live view image. Furthermore, it is also suitable for avoiding the hunting phenomenon during photometry caused by repeatedly driving the aperture 362.

(2) The permissible aperture range for the second aperture value mentioned above is set based on the first aperture value, so the aperture limit range can be set within an appropriate range that corresponds to the brightness of the subject. Can be set.

(3) The permissible aperture range of the second aperture value (aperture value for live view) is always set on the open side more than the first aperture value (aperture value for photographing). Generally, the larger the aperture diameter of the diaphragm 362 (on the larger diameter side), the shallower the depth of focus of the subject image becomes, as described above, and thus the detection accuracy of the amount of image shift (phase difference) improves. In this embodiment, by setting the aperture value limit range on the side where the aperture diameter of the aperture 362 is made larger (open side) than the first aperture value, the accuracy of phase difference detection and, by extension, the accuracy of focus detection are reduced. It can be suppressed.

(4) When the brightness of the subject changes and the first aperture value is updated (newly calculated), the body-side control unit 230 updates the permissible aperture value range of the second aperture value. . Further, the body-side control unit 230 does not change the second aperture value if the second aperture value that has been set (previously calculated) is within the updated aperture limit range. With this configuration, the frequency of driving the aperture 362 during live view mode can be suppressed.

(5) The body-side control unit 230 changes the newly calculated first aperture value (aperture value for photography) due to a change in the brightness of the subject to the second aperture value set based on the previous calculation result. If the aperture value is more open, the second aperture value (live view aperture value) is set to be more open than the calculated first aperture value. Then, the permissible aperture range of the second aperture value is updated, and the second aperture value is reset (updated) using the updated aperture limit range. With this configuration, the aperture value limit range is set to the open side of the aperture 362 than the first aperture value, and the drive of the aperture 362 in live view mode is suppressed without reducing focus detection accuracy. be able to.

(6) The permissible aperture range of the second aperture value (aperture value for live view) is on the side that is opener than the first aperture value (in this embodiment, one stop wider than the first aperture value). side). Then, the body-side control unit 230 sets the newly set second aperture value to approximately the center of the permissible aperture value range. Therefore, in this embodiment, the second aperture value does not need to be reset (updated) unless the brightness information of the subject increases or decreases by 0.5 steps or more in terms of the apex value. With this configuration, the frequency of driving the diaphragm 362 can be appropriately suppressed.

(7) The body-side control unit 230 changes the upper and lower limits of the permissible aperture range of the second aperture value based on information on the interchangeable lens 3. With this configuration, an appropriate value can be set according to the optical characteristics of the lens 361, for example.

(8) The information on the interchangeable lens 3 is at least one of the error tolerance based on the difference in optical characteristics between the first aperture value and the second aperture value, the photographing distance, and the photographing magnification. With this configuration, the upper and lower limits of the aperture value restriction range can be appropriately set.

(9) The camera body 2 of the camera system 1 calculates a first aperture value (aperture value for shooting) and a second aperture value (aperture value for live view) by the body-side control unit 230, and calculates a second aperture value (aperture value for live view). The camera includes a body-side control unit 230 that instructs the interchangeable lens 3 to drive the aperture 362 to the aperture value of . With this configuration, the camera body 2 can perform calculations and send an instruction to the interchangeable lens 3 to drive the aperture 362 to the second aperture value. (10) The body-side control unit 230 sets the permissible aperture range of the second aperture value to an autofocus mode (for example, a mode in which once the shutter button is pressed halfway to focus, the focus position is fixed while the shutter button is pressed halfway), It may be changed depending on the mode (in which the focusing operation is repeated while the button is pressed halfway). Note that even in the manual mode, the aperture may be controlled within the permissible aperture value range of the second aperture value.

The following modifications are also within the scope of the invention, and it is also possible to combine one or more of the modifications with the embodiments described above.
(Modification 1) The processing executed by the camera system (camera system 1) of the embodiment described above is appropriately divided between the body-side control section 230 on the camera body 2 side and the lens-side control section 330 on the interchangeable lens 3 side. It may be configured to do so.
For example, the first aperture value and the second aperture value may be calculated on the camera body side, and the driving force for driving the aperture 362 on the interchangeable lens side may be transmitted from the camera body to the interchangeable lens. That is, in the camera body 2A, the body-side control unit 230 that calculates the first aperture value and the second aperture value, and the drive mechanism for the aperture 362 provided in the interchangeable lens 3A drive the aperture 362 to the second aperture value. It includes an actuator that generates power for and a transmission member that transmits the power to the interchangeable lens 3A. With this configuration, in the camera system, driving of the aperture 362 during live view mode can be suppressed.

(Modification 2) Alternatively, the first aperture value and the second aperture value may be calculated on the camera body side, and the second aperture value may be transmitted from the camera body to the interchangeable lens. When the interchangeable lens receives the second aperture value, the aperture drive unit 380 drives the aperture 362 to the second aperture value. That is, the interchangeable lens 3B includes a lens-side communication section 340 that receives the second aperture value set by the body-side control section 230 of the camera body 2, an aperture drive section 380 that drives the aperture 362, and an aperture drive section 380. and a lens-side control unit 330 that instructs to drive the aperture 362 to the second aperture value received by the lens-side communication unit 340. With this configuration, the frequency of driving the aperture 362 in the live view mode can be appropriately suppressed in the camera system.

Note that, in the above example, the lens control unit 330 controls the aperture 362 using the aperture value (Av value) based on the apex calculation, but the lens control unit 330 controls the aperture value of the interchangeable lens 3. Control may also be performed using the value of the number of stops from the open aperture value.

(Modification 3) In the camera system (camera system 1) of the embodiment described above, two aperture values, a first aperture value and a second aperture value, are calculated in the body-side control unit 230 of the camera body 2, and the communication The configuration is such that two aperture values, a first aperture value and a second aperture value, are transmitted to the lens-side control unit 330 of the interchangeable lens 3 via the lens controller. However, the present invention is not limited to this, and only the first aperture value may be calculated in the body-side control section 230, and only the first aperture value may be transmitted to the lens-side control section 330 via the communication section. In that case, the second aperture value is autonomously set by the lens-side control unit 330. That is, the lens-side control unit 330 of the interchangeable lens 3 sets the second aperture value, which is the live view aperture value, within the permissible aperture value range based on the first aperture value received from the camera body 2.
Similar to the above embodiment, the permissible aperture range of the second aperture value (aperture value for live view) set by the lens-side control unit 330 is larger than the first aperture value (aperture value for shooting). Always keep it on the open side. The lens-side control unit 330 of the interchangeable lens 3 then compares the first aperture value transmitted from the camera body 2 with the currently set second aperture value. Similarly to the embodiment described above, even if the first aperture value received from the camera body 2 changes, the lens-side control unit 330 can receive the received aperture value as long as the second aperture value is set within the permissible aperture value range. The configuration is such that the set second aperture value is maintained without changing immediately in conjunction with the first aperture value that has been set. Similar to the above-described embodiment, the lens-side control unit 330 of the interchangeable lens 3 sets the permissible aperture range of the second aperture value (aperture value for live view) from the first aperture value (aperture value for shooting). If you set the second aperture value to approximately the center of the permissible aperture range, as long as the brightness information of the subject does not increase or decrease by more than 0.5 stops in the apex value, There is no need to reset (update) the second aperture value. With this configuration, the frequency of driving the diaphragm 362 can be appropriately suppressed.
Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments considered within the technical spirit of the present invention are also included within the scope of the present invention.

The disclosures of the following priority basic applications are incorporated herein by reference:
Japanese Patent Application No. 2018-135197 (filed on July 18, 2018)

DESCRIPTION OF SYMBOLS 1... Camera system, 2... Camera body, 3... Interchangeable lens, 230... Body side control part, 235... Storage part, 240... Body side communication part, 270... Signal processing part, 290... Display part, 330... Lens side control 340...Lens side communication unit, 350...Lens side storage unit, 360...Photographing lens, 362...Aperture, 370...Lens drive unit, 380...Aperture drive unit

Claims (1)

an imaging unit that captures an image of light incident through an optical system having an aperture and outputs a signal;
The first aperture value during which the imaging unit performs imaging to record image data based on the signal is the second aperture value during which the imaging unit performs imaging to display an image based on the signal on the display unit. when the difference between the first aperture value and the second aperture value is greater than the first value, a first control is performed to change the second aperture value based on the first aperture value. a control unit;
An imaging device comprising:

Images