JP2016213520A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device having plural shutter controls that can more greatly enhance usability for users.SOLUTION: An imaging device includes an imaging element for capturing a subject image, a mechanical shutter for shielding a subject image focused on the imaging element, and an exposure controller for controlling the imaging device and the mechanical shutter. The exposure controller may include a first shutter control for performing exposure by using the mechanical shutter and an electronic shutter of the imaging element in combination, and a second shutter control for performing exposure by using the electronic shutter of the imaging element without using the mechanical shutter. The exposure controller switches the first shutter control and the second shutter control to each other according to a shutter speed.SELECTED DRAWING: Figure 8

Description

  The present disclosure relates to an imaging apparatus. In particular, the present invention relates to an imaging apparatus having a plurality of shutter controls.

  Patent Document 1 discloses an imaging apparatus that realizes exposure by using a mechanical shutter and an electronic shutter together.

JP 2007-282128 A

  The present disclosure provides an imaging apparatus capable of improving the usability of a user in an imaging apparatus having a plurality of shutter controls.

  An imaging apparatus according to the present disclosure includes an imaging device that captures a subject image, a mechanical shutter that shields the subject image focused on the imaging device, and an exposure control unit that controls the imaging device and the mechanical shutter. The exposure control unit realizes the exposure using the electronic shutter of the image sensor without using the mechanical shutter and the first shutter control that realizes the exposure by using the mechanical shutter and the electronic shutter of the image sensor together. And the exposure control unit switches between the first shutter control and the second shutter control in accordance with a shutter speed.

  The imaging device according to the present disclosure can improve the usability of the user in an imaging device having a plurality of shutter controls.

External view of digital camera 100 according to Embodiment 1 Rear view of digital camera 100 according to Embodiment 1 Configuration diagram of digital camera 100 according to Embodiment 1 The figure for demonstrating the exposure timing in an electronic shutter and an electronic front curtain FIG. 10 is a diagram illustrating an example of a mode selection screen for determining shutter control in the first embodiment Control flowchart at the time of program diagram determination operation according to the mode in the first embodiment The figure for demonstrating the program diagram according to the mode in Embodiment 1 Flowchart for explaining shutter control according to the mode in the first embodiment

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The inventor (s) provides the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and is intended to limit the subject matter described in the claims. Not what you want.

(Embodiment 1)
Hereinafter, Embodiment 1 will be described with reference to FIGS.

<1. Configuration>
<1-1. Outline of configuration>
An outline of the configuration of the digital camera 100 according to the first embodiment will be described.

  FIG. 1 is an external view of the digital camera 100. As shown in FIG. 1, the digital camera 100 includes an interchangeable lens 101 and a camera body 102 to which the interchangeable lens 101 can be attached. The camera body 102 includes a release button 160. When the camera body 102 receives a half-press operation by the user of the release button 160, the camera body 102 transmits a control signal to the interchangeable lens 101 so as to perform an autofocus operation. Further, when the camera body 102 receives an operation by the user of the release button 160, the camera body 102 performs a photographing operation of a subject image formed via the interchangeable lens 101.

  FIG. 2 is a rear view of the digital camera 100 (camera body 102). The camera body 102 includes a liquid crystal monitor 163, a touch panel 162, a camera side operation unit 170 including a center button 204 and a cross button 205 on the back surface. The camera body 102 can receive various operations according to the operation content by accepting an operation by the user of the touch panel 162 or the camera side operation unit 170.

  FIG. 3 is a configuration diagram of the digital camera 100 (the interchangeable lens 101 and the camera body 102). The interchangeable lens 101 includes an optical system including a lens controller 120, a lens mount 130, a focus lens 110, and a zoom lens 112, a focus lens driving unit 111, a focus ring 114, a zoom lens driving unit 113, a zoom ring 115, an aperture 116, and an aperture drive. Unit 117, DRAM 121, flash memory 122, and the like. The camera body 102 includes a camera controller 153, a body mount 140, a CMOS image sensor 150, a timing generator 151 (hereinafter referred to as TG 151), an analog front end 152 (hereinafter referred to as AFE 152), and a liquid crystal. A monitor 163, a touch panel 162, a release button 160, a camera side operation unit 170, a power source 154, a DRAM 155, a flash memory 156, a mechanical shutter 157, a card slot 165, a memory card 164, and the like are provided.

<1-2. Configuration of each part of interchangeable lens>
Next, the configuration of each part of the interchangeable lens 101 will be described.

  The lens system includes a focus lens 110 and a zoom lens 112, and collects light from the subject. The zoom lens 112 is driven by the zoom lens driving unit 113 or the zoom ring 115 to adjust the zoom magnification. The focus lens 110 is driven by the focus lens driving unit 111 or the focus ring 114 to adjust the focus. In short, the focus lens 110 and the zoom lens 112 are movable lenses.

  The zoom lens driving unit 113 is configured to drive the zoom lens 112 according to the control of the lens controller 120. Further, the focus lens driving unit 111 drives the focus lens 110 within the drive control range indicated by the lens data in accordance with the control of the lens controller 120.

  The diaphragm 116 adjusts the amount of light that passes through the lens system and enters the CMOS image sensor 150. For example, the light can be adjusted by increasing or decreasing the opening formed by five blades or the like.

  The diaphragm driving unit 117 changes the size of the opening of the diaphragm 116. The lens controller 120 can control to change the size of the opening of the diaphragm 116. Here, the size of the opening can be designated from the camera controller 153 to the lens controller 120 by an Av value. Thus, for example, during exposure control, the camera controller 153 can control opening and closing of the aperture 116 according to the determined aperture value (Av value).

  The aperture driving unit 117 drives the aperture 116 based on control from the lens controller 120. In this case, the aperture driving unit 117 acquires a control signal (aperture value or driving amount) for adjusting the aperture from the lens controller 120. As a result, the aperture driving unit 117 drives the aperture within the drive control range indicated by the lens data in accordance with a control signal for adjusting the aperture.

  The zoom ring 115 is provided on the exterior of the interchangeable lens 101, and drives the zoom lens 112 in accordance with an operation from the user. The focus ring 114 is provided on the exterior of the interchangeable lens 101, and drives the focus lens 110 in accordance with an operation from the user.

  The flash memory 122 stores lens data representing the lens characteristics of the interchangeable lens 101. The lens data represents data in a form in which the camera controller 153 can recognize the lens name, F value, focal length, and the like.

  The lens controller 120 controls the entire interchangeable lens 101. The lens controller 120 may be realized by a microcomputer or a hard-wired circuit. When the interchangeable lens 101 is attached to the camera body 102, the lens controller 120 reads out lens data stored in the flash memory 122 and transmits it to the camera controller 153.

<1-3. Configuration of camera body parts>
Next, the configuration of each part of the camera body 102 will be described.

  The camera controller 153 controls the entire digital camera 100 such as the CMOS image sensor 150 in response to an instruction from the release button 160 or the camera side operation unit 170. The camera controller 153 notifies the timing generator 151 (TG) of the vertical synchronization signal. In parallel with this, the camera controller 153 generates an exposure synchronization signal based on the vertical synchronization signal. The camera controller 153 periodically and repeatedly notifies the lens controller 120 of the generated exposure synchronization signal via the body mount 140 and the lens mount 130. The camera controller 153 is connected to the DRAM 155 and the flash memory 156, and can write and read information as necessary. The camera controller 153 may be configured with a hard-wired electronic circuit or a microcomputer using a program.

  The DRAM 155 is used as a work memory for various controls by the camera controller 153. The flash memory 156 stores programs, parameters, and the like used for various controls by the camera controller 153. For example, the flash memory 156 stores a program diagram used for exposure control. A plurality of program diagrams may be stored corresponding to the photographing modes.

  The CMOS image sensor 150 captures a subject image incident through the interchangeable lens 101 and generates image information. The generated image information is converted from analog format data to digital format data by the AFE 152. The image information digitized by the AFE 152 is subjected to various image processing by the camera controller 153. Examples of the various types of image processing include gamma correction processing, white balance correction processing, scratch correction processing, YC conversion processing, electronic zoom processing, and JPEG compression processing, but are not limited thereto. In the present invention, instead of the CMOS image sensor 150, another image pickup device such as an NMOS image sensor or a CCD image sensor may be used.

  The CMOS image sensor 150 operates at a timing controlled by the TG 151. The operations of the CMOS image sensor 150 controlled by the TG 151 include a still image capturing operation, a through image capturing operation, a data transfer operation, an electronic shutter operation, and an electronic front curtain operation. The through image is mainly a moving image and is displayed on the liquid crystal monitor 163 in order to determine a composition for capturing a still image.

  The mechanical shutter 157 switches between blocking or passing an optical signal incident to the CMOS image sensor 150 through the lens system. The mechanical shutter 157 is driven by a mechanical shutter driving unit. The mechanical shutter driving unit includes mechanical parts such as a motor and a spring, and drives the mechanical shutter 157 under the control of the camera controller 153. In short, the mechanical shutter 157 is opened and closed to adjust the amount of light hitting the CMOS image sensor 150 in terms of time.

  The liquid crystal monitor 163 is arranged on the back surface of the camera body 102 and displays an image indicated by the display image information processed by the camera controller 153. The liquid crystal monitor 163 can selectively display both moving images and still images. In addition to images, setting conditions for the entire digital camera 100 can be displayed. In this embodiment, the liquid crystal monitor 163 is shown as an example of the display means, but the present invention is not limited to this. For example, display means such as an organic EL display may be used.

  The touch panel 162 is provided on the surface of the liquid crystal monitor 163, and generates information regarding the electrode position on the touch panel touched by the user. The touch panel 162 calculates the position coordinates on the touch panel touched by the user based on the information on the electrode position, and notifies the camera controller 153 of the position coordinates.

  The body mount 140 is a connecting member for mechanically and electrically connecting the interchangeable lens 101 and the camera body 102 together with the lens mount 130 included in the interchangeable lens 101. When the interchangeable lens 101 and the camera body 102 are mechanically and electrically connected, the lens controller 120 and the camera controller 153 can communicate with each other. The body mount 140 notifies the lens controller 120 of the exposure synchronization signal and other control signals received from the camera controller 153 via the lens mount 130. The body mount 140 notifies the camera controller 153 of a signal received from the lens controller 120 via the lens mount 130.

  The power source 154 supplies power to be consumed by the digital camera 100. The power source 154 may be, for example, a dry battery or a rechargeable battery. Moreover, the power supplied from the outside by the power cord may be supplied to the digital camera 100. When the power is turned on, the camera controller 153 supplies power to the entire camera body 102. The camera controller 153 supplies power to the interchangeable lens 101 via the body mount 140 and the lens mount 130. Then, the lens controller 120 supplies power to the entire interchangeable lens 101.

  The card slot 165 is a connection means to / from which the memory card 164 can be attached / detached. The card slot 165 can connect the memory card 164 electrically and mechanically. The card slot 165 may have a function of controlling the memory card 164.

  The memory card 164 is an external memory provided with storage means such as a flash memory. The memory card 164 can store data such as image information processed by the camera controller 153. The memory card 164 can output data such as image information stored therein. The image information output from the memory card 164 is processed by the camera controller 153 and reproduced and displayed on the liquid crystal monitor 163, for example.

  The release button 160 receives a user operation. The release button 160 is operated in two steps, half-press and full-press. When the user half-presses the release button 160, the camera controller 153 performs an autofocus operation. When the user fully presses the release button 160, the camera controller 153 stores the image information generated according to the timing of the full pressing operation in the memory card 164.

  The camera side operation unit 170 is a general term for operation members including the above-described center button 204 and cross button 205. The camera side operation unit 170 includes a switch for switching between MF / AF. When the camera side operation unit 170 receives an operation by the user, the camera controller 153 executes various controls according to the operation instruction content.

<1-4. Difference in exposure timing due to difference between shutter control that can be performed by the digital camera 100 and shutter control (FIG. 4)>
In the first embodiment, the camera controller 153 can control the mechanical shutter 157 and the CMOS image sensor 150 to realize exposure by the electronic shutter and exposure by the electronic front curtain. The electronic shutter is a technique for realizing both the front curtain and the rear curtain with an image sensor. The electronic front curtain is a technology that realizes the front curtain with an image sensor and the rear curtain with a mechanical shutter. In the embodiment, the camera controller 153 is configured to control the CMOS image sensor 150 in order to realize an electronic shutter. In order to realize an electronic front curtain, the camera controller 153 is configured to control the mechanical shutter 157 and the CMOS image sensor 150. Hereinafter, for simplification of description, the terms electronic shutter and electronic front curtain are used for description.

  For example, the digital camera 100 has a plurality of shutter controls in order to adjust the exposure time of the CMOS image sensor 150. The digital camera 100 has an electronic shutter and an electronic front curtain as shutter control.

  Here, the electronic shutter is a control that is electronically performed by the CMOS image sensor 150 at both the start and end of exposure as shown in FIG. Since the electronic shutter control electronically controls the exposure time, high-speed shutter speed control can be performed with high accuracy. However, the electronic shutter control moves because the difference in exposure timing between the upper and lower surfaces of the CMOS image sensor 150 is long. There is a possibility that a phenomenon in which the subject is distorted (hereinafter referred to as rolling shutter distortion) occurs when the subject is imaged.

  Further, as shown in FIG. 4, the electronic front curtain is a control in which exposure is started electronically by the CMOS image sensor 150 and light exposure is shielded by the mechanical shutter 157. Since the difference in exposure timing between the top and bottom of the imaging surface of the CMOS image sensor 150 is relatively short, the above-described rolling shutter distortion is unlikely to occur. However, since exposure control is performed by a mechanical mechanism, variations in operation occur and high shutter speeds occur. It is difficult to obtain the accuracy of time.

  As shown in FIG. 4, the electronic shutter has a longer readout time than the electronic front curtain. As a result, there is a possibility that the electronic shutter cannot perform proper flash photography as compared with the electronic front curtain. This is because in the electronic shutter, it is necessary to read out the imaging line at the same timing as the end of exposure.

  In addition, since the electronic front curtain performs exposure by controlling the mechanical shutter as compared with the electronic shutter, the exposure amount varies greatly in high-speed shooting.

  Furthermore, the electronic shutter takes a longer time from the start line to the end line than the electronic front curtain. As a result, the electronic shutter has a larger rolling shutter distortion than the electronic front curtain.

  As described above, the electronic shutter and the electronic front curtain have various advantages and disadvantages.

  It is difficult for the user to switch between the electronic shutter and the electronic front curtain in consideration of such a difference.

  Therefore, in the first embodiment, the following operation is enabled.

<2. Operation>
<2-1. Imaging preparation operation>
First, the operation of the digital camera 100 for preparation for imaging will be described.

  When the user turns on the camera body 102 with the interchangeable lens 101 mounted on the camera body 102, the power source 154 supplies power to the interchangeable lens 101 via the body mount 140 and the lens mount 130. Next, the camera controller 153 requests the lens controller 120 for authentication information of the interchangeable lens 101 and requests information necessary for controlling the interchangeable lens 101 such as lens data. When the camera controller 153 obtains information necessary for controlling the interchangeable lens 101, the camera controller 153 controls the camera body 102 to a state where it can be photographed.

  In this state, the digital camera 100 can operate in a control mode in which an image indicated by the image data generated by the CMOS image sensor 150 is displayed on the liquid crystal monitor 163 as a through image. This control mode is called live view mode. In the live view mode, the through image is displayed as a moving image on the liquid crystal monitor 163, so that the user can determine the composition for capturing a still image while viewing the liquid crystal monitor 163.

<2-2. Mode selection operation for determining shutter control (FIG. 5)>
The digital camera 100 can cause the user to set a mode for determining shutter control. The mode setting by the user will be described with reference to FIG.

  The digital camera 100 has three types of modes. The three types of modes include “electronic shutter fixing”, “electronic front curtain fixing”, and “automatic control” (the camera automatically determines the electronic shutter and electronic front curtain).

  The camera controller 153 causes the liquid crystal monitor 163 to display a mode selection screen for allowing the user to select these modes. An example of the mode selection screen is shown in FIG. FIG. 5 shows a mode selection setting screen D400. The user operates the camera side operation unit 170 to move the selection cursor D401 and select a desired mode from the three types of modes. The camera controller 153 stores the selected mode in the DRAM 155.

<2-3. Program diagram determination operation (FIG. 6)>
The operation of the digital camera 100 for determining the program diagram will be described with reference to FIG.

  As shown in FIG. 6, the camera controller 153 determines a program diagram according to the mode setting stored in the DRAM 155 (S1). If the mode is the electronic front curtain, the camera controller 153 adopts a program diagram dedicated to the electronic front curtain (S2). If the mode is automatic control, the camera controller 153 employs a program diagram for automatic control (S3). If the mode is fixed to the electronic shutter, the camera controller 153 employs a program diagram dedicated to the electronic shutter (S4). The camera controller 153 stores the adopted program diagram in the DRAM 155 (S5). An example of a program diagram to be adopted is shown in FIG.

  FIG. 7A is a program diagram dedicated to the electronic shutter. FIG. 7B is a program diagram dedicated to the electronic front curtain. FIG. 7C is a program diagram for automatic control.

Here, the program diagram dedicated to the electronic front curtain limits the upper limit compared to the electronic shutter (upper limit = TV _B ). The reason for lowering the upper limit in the electronic front curtain is that there is a possibility that an appropriate captured image cannot be generated because the exposure amount varies greatly in high-speed shooting.

The program diagram for automatic control, the TV value below TV _B utilizes the program line of the electronic front curtain for greater than TV _B utilizes any program diagram.

  That is, when the mode is set to automatic control, the digital camera 100 may adopt a part of the program diagram of the electronic front curtain as the program diagram. In automatic control, the TV value can be suppressed by using the program diagram of the electronic front curtain. As a result, in the automatic control, the electronic front curtain is selected with priority over the electronic shutter and is used for the control, so that occurrence of rolling shutter distortion or the like of the captured image can be reduced.

  Note that the camera controller 153 obtains the AV value and the TV value using the EV value based on the photometric result obtained by the CMOS image sensor 150 and the program diagram to be adopted immediately before photographing. The camera controller 153 records the obtained AV value and TV value in the DRAM 155.

<2-4. Shutter control determination operation (FIG. 8)>
Next, the operation of the digital camera 100 for determining shutter control will be described with reference to FIG. As illustrated in FIG. 8, the camera controller 153 determines shutter control according to the mode setting stored in the DRAM 155 and the TV value stored in the DRAM 155 immediately before shooting.

The camera controller 153 reads the mode setting information stored in the DRAM 155 and checks the setting information (S11). If the mode is fixed to the electronic front curtain, the camera controller 153 determines the shutter control to be the electronic front curtain (S12). When the mode is automatic control, the camera controller 153 determines whether or not the TV value stored in the DRAM 155 is larger than a predetermined value (for example, TV _B ) (S13). If the TV value is equal to or less than the predetermined value, the camera controller 153 determines the shutter control to be the electronic front curtain (S12). On the other hand, if the TV value is larger than the predetermined value, the camera controller 153 determines the shutter control to be an electronic shutter (S14). Returning to the process of S11, the camera controller 153 determines the shutter control to be the electronic shutter when the mode is fixed to the electronic shutter (S14).

<2-5. Shooting action>
The digital camera 100 obtains the TV value from the program diagram obtained in FIG. 6 when the release button is pressed halfway. Thereafter, if the mode is automatic control, the digital camera 100 determines shutter control based on the TV value. Then, when the release button is fully pressed, the digital camera 100 performs a shooting operation, acquires a still image (captured image), and records it in the memory card 164.

<2-6. Effect>
As described above, the digital camera 100 according to the first embodiment can be set to the automatic control mode by the user. In the automatic control mode, the digital camera 100 switches between the electronic front curtain and the electronic shutter according to the shutter speed.

  Since it comprised in this way, the shutter control which each has a merit and a demerit like an electronic shutter and an electronic front curtain can be switched according to the setting of a camera. As a result, a more preferable captured image can be provided to the user.

  The digital camera 100 according to the first embodiment uses part of the program diagram of the electronic front curtain as the program diagram in the automatic control mode.

  In this way, since the digital camera 100 can determine the electronic front curtain in preference to the electronic shutter as shutter control, a more preferable captured image can be provided to the user.

(Other embodiments)
As described above, the first embodiment has been described as an example of the technique disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed.

  Therefore, other embodiments will be exemplified below.

  In the first embodiment, the shutter speed (TV value) is determined using the program diagram. However, the present invention is not limited to this, and the shutter speed (TV value) may be determined in a shooting mode such as an aperture priority mode, a shutter priority mode, or a manual mode. For example, in the aperture priority mode, the TV value may be obtained using the AV value set by the user and the EV value based on the photometric result obtained by the image sensor. In the shutter priority mode or the manual mode, the TV value may be obtained from the shutter speed set by the user. Note that ISO conversion is omitted in the embodiment for simplification of description.

  As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided.

  Accordingly, among the components described in the accompanying drawings and the detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  Moreover, since the above-mentioned embodiment is for demonstrating the technique in this indication, a various change, replacement, addition, abbreviation, etc. can be performed in a claim or its equivalent range.

  The present disclosure is applicable to digital cameras, movies, smartphones, and the like.

DESCRIPTION OF SYMBOLS 100 Digital camera 101 Interchangeable lens 102 Camera body 110 Focus lens 111 Focus lens drive part 112 Zoom lens 113 Zoom lens drive part 114 Focus ring 115 Zoom ring 116 Diaphragm 117 Diaphragm drive part 120 Lens controller 121 DRAM
122 Flash memory 130 Lens mount 140 Body mount 150 CMOS image sensor 151 TG
152 AFE
153 Camera controller 154 Power supply 155 DRAM
156 Flash memory 157 Mechanical shutter 160 Release button 162 Touch panel 163 LCD monitor 164 Memory card 165 Card slot 170 Camera side operation unit 204 Center button 205 Cross-shaped button

Claims (1)

An image sensor for capturing a subject image;
A mechanical shutter that shields a subject image condensed on the image sensor;
An exposure control unit for controlling the image sensor and the mechanical shutter;
With
The exposure control unit
A first shutter control for realizing exposure by using the mechanical shutter and the electronic shutter of the image sensor together;
A second shutter control that realizes exposure using the electronic shutter of the image sensor without using the mechanical shutter;
Have
The exposure control unit switches between the first shutter control and the second shutter control according to a shutter speed;
Imaging device.

Images