JP5413049B2 - Imaging apparatus and imaging apparatus control method - Google Patents

Description

  The present invention relates to an imaging apparatus that continuously images a subject and an imaging apparatus control method.

  Even if it is set to preferentially execute the release operation regardless of the in-focus state, the release is prohibited until the defocus amount becomes a predetermined value or less, so that imaging cannot be performed. An imaging device to be controlled has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 2-42428

  However, as in the technique disclosed in Patent Document 1, if control is performed to prohibit the release operation even though the release operation is set to be executed preferentially, a release has occurred and a release has occurred. There was a problem that the user misunderstood that it couldn't be done and was easily confused.

  In view of the above circumstances, an object of the present invention is to provide an imaging apparatus and an imaging apparatus control method that can prevent a user from misinterpreting a failure when performing a release operation.

One embodiment of the present invention is an imaging apparatus, and a focus detection unit that detects a focus state of an optical system, and a focus adjustment of the optical system based on the focus state by driving a lens included in the optical system. A focus adjustment unit that performs imaging, an imaging unit that repeatedly captures an image by the optical system, and when the focus adjustment by the focus adjustment unit is controlled to be executable during imaging based on the focus state, It is determined whether the driving amount of the lens based on the defocus amount is larger than a preset threshold value. When the driving amount of the lens is larger than the threshold value, the lens is being driven. was captured by start exposure on the imaging unit, when the drive amount of the lens is less than the threshold value, and a control unit the imaging unit stops the driving of the lens to the start of exposure .

  In one embodiment of the present invention, in the imaging apparatus, the focus detection unit detects the focus state at an imaging interval of the imaging unit, and the control unit cannot regard the focus state as a focused state. In addition, control is performed so that the focus adjustment by the focus adjustment unit is performed during imaging.

  One embodiment of the present invention further includes a recording unit that records an image captured by the imaging unit in the imaging apparatus, wherein the recording unit is subjected to the focus adjustment by the focus adjustment unit during imaging. In this case, the captured image is not recorded.

One embodiment of the present invention is an imaging apparatus, a focus detection unit that detects a focus state of an optical system, a focus adjustment unit that performs focus adjustment of the optical system based on the focus state, and an image by the optical system When the imaging is repeated, even if the predetermined number of continuous imaging is exceeded, the imaging unit that continues the continuous imaging until the imaging is performed after the driving of the lens included in the optical system is stopped, and the focus state And a control unit that controls the focus adjustment by the focus adjustment unit to be executable during imaging.

One aspect of the present invention is a method for controlling an imaging apparatus, wherein the imaging apparatus detects a focus state of an optical system, and the imaging apparatus drives the lens included in the optical system, thereby the focus. A focus adjustment step of performing focus adjustment of the optical system based on a state; an imaging step in which the imaging device repeatedly captures an image by the optical system; and the imaging device during imaging based on the focus state When controlling the focus adjustment to be executable, it is determined whether or not the driving amount of the lens based on the defocus amount as the focus state is larger than a preset threshold value, and the driving amount of the lens is the threshold value When the lens is being driven, the exposure in the imaging step is started while the lens is being driven, and imaging is performed. And a control step of stopping the driving of the lens to the start of exposure in imaging step.

  According to the present invention, it is possible to prevent a user from misinterpreting as a failure when performing a release operation.

It is a schematic block diagram showing the function structure of an imaging device. It is a flowchart showing operation | movement in case an imaging device performs continuous imaging. It is the figure which represented typically the operation | movement of the continuous imaging by an imaging device. It is a figure showing the specific example of the movement of the focus adjustment lens in the continuous imaging by an imaging device.

  FIG. 1 is a schematic block diagram illustrating a functional configuration of the imaging apparatus 1. FIG. 1 illustrates a functional configuration when the imaging device 1 is configured as a single-lens reflex digital still camera, but the imaging device 1 may be configured as various digital imaging devices such as a digital video camera.

  The imaging apparatus 1 includes an imaging optical system 101, a quick return mirror 102, a focusing screen 103, a pentaprism 104, an eyepiece lens 105, a photometric lens 106, a photometric sensor 107, an imaging unit 108, an image recording unit 109, a sub mirror 110, and an AF module. 111, a lens driving amount calculation unit 112, a lens driving motor 113, a lens driving control unit 114, and an operation unit 115.

  The photographing optical system 101 (optical systems 101 a to 101 c) forms an image of a subject to be photographed on the imaging surface of the image sensor 106. The optical system 101a and the optical system 101c are fixedly installed in the lens barrel. The optical system 101 b is a focus adjustment lens that can move in the optical axis direction by the power of the lens driving motor 113.

  The quick return mirror 102 reflects light to the pentaprism 104 before exposure. On the other hand, the quick return mirror 102 jumps upward during exposure and moves to the lower side of the focusing screen 103 so that the light transmitted through the photographing optical system 101 can be received by the imaging unit 108. The quick return mirror 102 is configured as a half mirror near the center, and transmits a part of light from the subject.

The focusing screen 103 forms a subject image by light from the subject reflected by the quick return mirror 102.
The pentaprism 104 reflects the light beam so that the subject image formed on the focusing screen 103 is horizontally reversed so that the eyepiece 105 and the photometric lens 106 can receive the light.

  The eyepiece 105 allows the photographer to observe the image on the focusing screen 103 via the pentaprism 104.

The photometric lens 106 forms an image of the subject on the focusing screen 103 reflected by the pentaprism 104 so as to be reversed left and right on the photometric sensor 107.
The photometric sensor 107 is configured by arranging a plurality of light receiving elements such as a CMOS sensor and a CCD, receives the light transmitted through the photometric lens 106, converts it into an electrical signal, and is the same as the subject imaged by the imaging unit 108. An image signal of the subject image is generated.

  The imaging unit 108 includes an imaging element in which a plurality of light receiving elements such as a CMOS sensor (Complementary Metal Oxide Semiconductor) and a CCD (Charge Coupled Device) are arranged, a shutter, and the like, and receives light from a subject transmitted through the imaging optical system 101. The image sensor receives light and converts it into an electrical signal to generate image data. In addition, when the continuous imaging mode (continuous shooting mode) is set, the imaging unit 108 continuously performs imaging a plurality of times at regular time intervals in response to the release button being pressed once. The number of continuous imaging is set in advance by a user or a designer. Note that the imaging unit 108 may include an infrared cut filter for cutting infrared light, an optical low-pass filter for preventing aliasing noise, and the like on the front surface of the image sensor.

The image recording unit 109 is configured using a recording medium such as a magnetic hard disk or a semiconductor memory, and records image data captured by the imaging unit 108.
The sub mirror 110 reflects the light transmitted through the half mirror portions of the photographing optical system 101 and the quick return mirror 102 to the AF module 111.

  The AF module 111 is installed on the bottom side of the body of the imaging apparatus 1 and includes a mask, a separator lens, a CCD sensor unit, and the like. The AF module 111 detects data in each of one or more AF areas based on a phase difference detection method based on a light reception signal obtained by receiving a pair of light beams that pass through a pair of regions having different exit pupils of the photographing optical system 101. Calculate the focus amount.

  The lens driving amount calculation unit 112 calculates the lens driving amount based on the defocus amount calculated by the AF module 111. The lens driving amount is a movement amount for moving the focus adjustment lens 101b to a position where the defocus amount becomes zero.

The lens driving motor 113 is an actuator for driving the focus adjustment lens 101b of the photographing optical system 101 in the optical axis direction.
The lens drive control unit 114 drives the lens drive motor 113 based on the lens drive amount calculated by the lens drive amount calculation unit 112, and moves the focus adjustment lens 101b in the optical axis direction so that the subject is in focus. Move.

  The operation unit 115 includes an autofocus area (AF area) selection switch for selecting a subject to be focused on, an imaging mode selection switch for selecting an imaging mode (continuous imaging mode, moving image imaging mode, etc.), an imaging instruction, and the like. A release button or the like for inputting.

  FIG. 2 is a flowchart showing an operation when the imaging apparatus 1 performs continuous imaging. Hereinafter, the operation during continuous imaging of the imaging apparatus 1 will be described with reference to FIG. When the user sets the imaging mode selection switch of the operation unit 115 to the continuous imaging mode and presses the release button, the AF module 111 first controls the gain and accumulation time of the AF sensor (CCD sensor unit) to store charges. Start (step S101). Next, the AF module 111 reads the accumulated information from the AF sensor (step S102), and calculates the defocus amount of each AF area based on the accumulated information (step S103). The AF module 111 repeatedly executes the processes of steps S102 and S103 until the defocus amounts of all AF areas to be autofocused are calculated (step S104—NO).

  When the calculation of the defocus amount ends (step S104—YES), the lens drive amount calculation unit 112 calculates the lens drive amount based on the calculated defocus amount (step S105). Next, the lens drive control unit 114 determines whether or not the lens driving motor 113 is stopped. If the lens driving motor 113 is stopped (YES in step S106), the lens driving motor 113 determines whether the lens driving motor 113 is based on the lens driving amount. Drive control is started (step S107). When the drive control of the lens driving motor 113 is started, the lens driving motor 113 continues to be driven until the lens driving stop process described later is performed, and the focus adjustment lens 101b of the photographing optical system 101 continues to move.

  Next, the lens driving control unit 114 selects whether or not to perform lens driving during exposure of the imaging unit 108. Specifically, the lens drive control unit 114 determines whether or not the lens drive amount calculated by the lens drive amount calculation unit 112 is greater than a preset threshold value (step S108). The threshold is set in advance as a lens driving amount that can be completed before the next imaging by the imaging unit 108 is performed. The lens driving amount that can be completed before the next imaging by the imaging unit 108 is performed is determined by the conversion coefficient for calculating the predetermined number of pulses for the defocus amount from the lens information, the performance of the lens driving motor 113, and the like. Therefore, a different value is set as the threshold value depending on the type of the photographing optical system 101 provided in the imaging apparatus 1 and the performance of the lens driving motor 113.

  When the lens driving amount is larger than the threshold (step S108—YES), the lens driving control unit 114 selects to perform lens driving during the exposure of the imaging unit 108. In this case, the lens drive control unit 114 does not stop driving the lens drive motor 113. Therefore, while the lens driving motor 113 is being driven, the imaging unit 108 starts exposure and performs imaging (step S109).

  If the lens drive amount is equal to or smaller than the threshold value in step S108 (step S108-NO), the lens drive control unit 114 selects not to drive the lens during the exposure of the imaging unit 108. In this case, the lens drive control unit 114 finishes the drive control of the lens drive motor 113 until the imaging unit 108 starts exposure, and stops the lens drive (step S112). Therefore, in this case, the imaging unit 108 performs imaging with the lens driving motor 113 stopped (step S109).

  After the imaging unit 108 performs imaging in step S109, the image recording unit 109 records the captured image data (step S110). Next, the imaging unit 108 determines whether or not the release operation has been completed (step S111). If the release operation has not been completed (step S111: NO), the imaging apparatus 1 repeatedly executes the processing from step S101. On the other hand, when the release operation is finished (step S111-YES), continuous imaging by the imaging device 1 is finished.

  FIG. 3 is a diagram schematically showing the operation of continuous imaging by the imaging apparatus 1. FIG. 4 is a diagram illustrating a specific example of the movement of the focus adjustment lens in continuous imaging by the imaging apparatus 1. Hereinafter, a specific example of the operation of the imaging apparatus 1 will be described with reference to FIGS. 3 and 4. In the specific example described below, it is assumed that the predetermined number of continuous imaging is set to three.

  In FIG. 3, the horizontal axis represents the flow of time, and time advances from left to right. The upper part of FIG. 3 is a timing chart showing the operation of the quick return mirror 102, and the vertical axis shows the position of the quick return mirror 102. In this timing chart, a horizontal line (broken line) at a low position in the vertical axis direction indicates that the quick return mirror 102 is located at a position shown in FIG. 1. At this time, the imaging unit 108 cannot perform exposure and does not perform imaging. Also, a horizontal line (thick line) at a high position in the vertical axis direction indicates that the quick return mirror 102 has moved to the lower side of the focusing screen 103. At this time, the imaging unit 108 performs exposure and imaging with the imaging device. Further, the diagonal line indicates that the quick return mirror 102 is moving.

  The middle part of FIG. 3 represents the execution timing of the processes of the AF module 111 and the lens driving amount calculation unit 112. The rectangles a, b, and c represent execution timings of charge accumulation processing (step S101), defocus amount calculation processing (step S103), and lens drive amount calculation processing (step S105) by the AF sensor, respectively. Further, arrows A to C extending downward from the lower right of the rectangle c determine whether or not the lens driving motor 113 is being driven (step S106), lens drive control start processing (step S107), and lens drive amount. Represents a timing at which the lens drive control unit 114 executes the determination (step S108) as to whether or not is greater than the threshold value.

  The lower part of FIG. 3 shows whether the lens driving motor 113 is driven or stopped. 4A to 4C show the position of the focus adjustment lens 101b at the time indicated by arrows A to C in FIG. 3, respectively. In FIG. 4, the symbol x represents the position of the focus adjustment lens for focusing on the subject, the symbol y represents the current position of the focus adjustment lens, the symbol Z represents the size of the lens drive amount threshold, and LA˜ LC represents the lens driving amount calculated at each time point.

  At the time indicated by the arrow A, since the lens drive is stopped (step S106-YES), the lens drive control unit 114 starts the lens drive control (step S107), and the lens is being driven. Further, since the lens driving amount at this time is larger than the threshold value (step S108—YES), the imaging unit 108 performs exposure while the lens driving control unit 114 is driving the lens driving motor 113, and the first time. Imaging is performed (step S109).

  At the point of arrow B, since the lens is being driven (step S106—NO), the lens driving start process is not executed. Further, since the lens driving amount at this time is larger than the threshold value (step S108—YES), the imaging unit 108 performs the exposure while the lens driving control unit 114 drives the lens driving motor 113, and the second time. Imaging is performed (step S109).

  At the time indicated by the arrow C, since the lens is being driven (step S106—NO), the lens driving start process is not executed. At this time, since the lens driving amount is equal to or less than the threshold (step S108-NO), the lens driving control unit 114 finishes driving control of the lens driving motor 113 and stops the lens driving (step S112). The imaging unit 108 performs exposure and performs the third imaging (step S109). In this specific example, it is assumed that the release operation is completed after the third release, and image data obtained by the third imaging is recorded (step S110), and the continuous imaging is completed.

  In the imaging apparatus 1 configured as described above, imaging is performed in response to pressing of the release button even if the lens has not moved to the position where the subject is in focus. Therefore, unlike the prior art which is controlled to prohibit the release operation, it is possible to prevent the user from misunderstanding that a failure has occurred.

  Further, among conventional techniques for performing continuous imaging, there is a technique for stopping lens driving each time imaging is performed during continuous imaging. In such a technique, when the lens driving amount is large, there is a problem that it takes a long time to complete the lens driving control. In order to deal with such a problem, the imaging device 1 performs imaging without stopping lens driving when the lens driving amount is larger than the threshold when performing imaging each time during execution of continuous imaging. Therefore, the time required for moving the lens to the position where the subject is actually focused (that is, the time required for completing the lens drive control) is shorter than when the lens drive is stopped each time an image is taken. It is shortened, and it becomes possible to reduce the frequency | count that imaging is performed in the state which is out of focus.

  Further, in the imaging device 1, even when the distance from the imaging device 1 to the subject fluctuates due to movement of the subject to be focused during continuous imaging, until the lens drive control is completed as described above. Therefore, it is possible to achieve focusing at high speed.

<Modification>
The imaging unit 108 is configured to continue continuous imaging until imaging is performed after the lens driving control unit 114 finishes the lens driving control and the lens driving is stopped even if the predetermined number of continuous imaging is exceeded. May be. Specifically, after the determination in step S111 in FIG. 2, the imaging unit 108 further determines whether or not the lens driving stop in step S112 has been executed even once, and the lens driving stop has not been executed. Repeats the processing from step S101, and when the lens driving stop is executed, the continuous imaging is finished. With this configuration, in continuous imaging, imaging is always performed with the focusing lens stopped once, and it is possible to obtain a captured image in a state where the subject is in focus. Become.

  The image recording unit 109 does not record the image data when the lens is driven during the exposure of the image sensor of the imaging unit 108 (image data captured when the lens driving amount is larger than the threshold value), and the image recording unit 109 It may be configured to record only image data (image data captured immediately after the lens driving stop process is performed) when the lens driving is stopped during the exposure of the imaging device.

The processing flow shown in FIG. 2 is an example, and the order may be changed as appropriate.
In the imaging apparatus 1 described above, a process of driving the focus adjustment lens 101b in the optical axis direction is adopted as a specific example of the focus adjustment. However, the focus adjustment may be realized by other existing processes. In this case, the lens driving amount described above is realized by replacing the time required for focus adjustment in other processing.
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Imaging device, 101 ... Imaging optical system, 102 ... Quick return mirror, 103 ... Focus plate, 104 ... Pentaprism, 105 ... Eyepiece lens, 106 ... Imaging part, 107 ... Submirror, 108 ... Lens for photometry, 109 ... Photometry Sensor 110 110 AF module 111 Lens drive amount calculation unit 112 Lens drive motor 113 Lens drive control unit 114 Image recording unit 115 Operation unit

Claims (5)

A focus detection unit for detecting the focus state of the optical system;
A focus adjustment unit that adjusts the focus of the optical system based on the focus state by driving a lens included in the optical system ;
An imaging unit that repeatedly captures images by the optical system;
When controlling the focus adjustment by the focus adjustment unit to be executable during imaging based on the focus state, the driving amount of the lens based on the defocus amount as the focus state is larger than a preset threshold value. If the lens driving amount is larger than the threshold value, the imaging unit starts exposure while the lens is being driven, and the lens driving amount is set to the threshold value. If the following, the control unit that stops the driving of the lens before the imaging unit starts exposure ,
An imaging apparatus comprising: The imaging device according to claim 1,
The focus detection unit
Detecting the focus state at intervals of imaging by the imaging unit;
The said control part is controlled to perform the said focus adjustment by the said focus adjustment part during imaging, when the said focus state cannot be regarded as a focusing state. The imaging device according to claim 1 or 2,
A recording unit that records an image captured by the imaging unit;
The recording unit does not record a captured image when the focus adjustment by the focus adjustment unit is performed during imaging. A focus detection unit for detecting the focus state of the optical system;
A focus adjustment unit that performs focus adjustment of the optical system based on the focus state;
An imaging unit that continuously captures an image after the drive of a lens included in the optical system is stopped, even when a predetermined number of continuous imaging is exceeded when repeatedly capturing images by the optical system; ,
A control unit that controls the focus adjustment by the focus adjustment unit during imaging based on the focus state;
An imaging apparatus comprising: A focus detection step in which the imaging device detects a focus state of the optical system;
A focus adjustment step in which the imaging apparatus performs focus adjustment of the optical system based on the focus state by driving a lens included in the optical system;
An imaging step in which the imaging device repeatedly captures an image by the optical system;
When the imaging device controls the focus adjustment to be executable during imaging based on the focus state, the driving amount of the lens based on the defocus amount as the focus state is larger than a preset threshold value When the driving amount of the lens is larger than the threshold value, exposure is started in the imaging step while the lens is being driven, and the lens driving amount is set to the threshold value. A control step for stopping the driving of the lens before the exposure in the imaging step is started ,
An imaging apparatus control method comprising:

Images