JP2015073165A - Imaging device - Google Patents

Abstract

To provide an imaging apparatus capable of maintaining exposure by changing imaging sensitivity and shutter speed even if the setting is unexpectedly changed due to a change in the aperture value of a lens. An exposure value setting means for setting an aperture value, a shutter speed, and an imaging sensitivity, an aperture value change determining means for determining whether or not an open aperture value or a minimum aperture value of the photographing lens has changed, and the aperture value change determination Means for changing the imaging sensitivity in a direction approaching the exposure value set by the exposure value setting means when it is determined that the open aperture value or the minimum aperture value has changed, An imaging sensitivity range determining unit that determines whether the imaging sensitivity changed by the first imaging sensitivity changing unit is within the first imaging sensitivity range; and the changed imaging sensitivity is the imaging sensitivity range. If it is determined by the determination means that it is not within the first imaging sensitivity range, the shutter is moved toward the exposure value set by the exposure value setting means. The first shutter speed changing means for changing the degree, has a structure characterized by having a city. [Selection] Figure 3

Description

  The present invention relates to an imaging apparatus such as an electronic still camera, and more particularly to a method for controlling an interchangeable lens imaging apparatus.

  When the shooting mode is the manual mode and the set aperture value is set to the full aperture value or the minimum aperture value of the lens, when the zoom is performed or the lens is replaced, the open aperture value and the minimum aperture value of the lens may change.

  At this time, when the set value exceeds the open aperture value or the minimum aperture value of the lens, the open aperture value or the minimum aperture value of the lens is forcibly set to the set value.

  When such a situation occurs, the user often does not notice that the setting value has changed, and in that case, the number of failed photos with different exposures increases.

  In order to solve this problem, there is a method of automatically changing the shutter speed so that there is no change in exposure (Patent Document 1). In Patent Document 1, it is determined whether or not the zoom lens has moved, and the amount of change in luminance is estimated based on the change in the aperture amount of the lens obtained in conjunction with the movement, and the shutter speed is changed. In the case of a camera whose imaging sensitivity can be changed, it is conceivable to change the imaging sensitivity instead of the shutter speed as the lens aperture changes.

JP 2008-263492 A

  However, in the conventional technique disclosed in Patent Document 1, when the changeable range of the imaging sensitivity and the changeable range of the shutter speed are rougher than the change range of the lens aperture, the image is captured as much as the change amount of the lens aperture. Sensitivity and shutter speed cannot be changed. For this reason, there is a problem that exposure maintenance control according to the change of the aperture of the lens cannot be performed.

  For example, the change of the lens aperture changes by 1/3 steps from F4 → 4.5 → 5 → 5.6, and the control range of the imaging sensitivity of the camera is ISO3600 → 2000 → 2500 → 3200 → 6400 up to ISO3200. Let's consider a case where 1/3 steps each, and 1 step further. In this case, when the imaging sensitivity is set to ISO 2500 and the aperture is changed from F4 to 4.5 → 5 → 5.6, the exposure can be maintained at F4.5 to ISO 3200, but when F5 or F5.6 is reached. It is impossible to set the imaging sensitivity that can maintain the exposure.

  Therefore, the present invention provides an imaging apparatus capable of maintaining exposure by changing imaging sensitivity and shutter speed even if the setting is unexpectedly changed due to a change in the aperture value of the lens.

  In order to solve the above problems, the present invention provides an exposure value setting means for setting an aperture value, a shutter speed, and an imaging sensitivity, and an aperture value change determination for determining whether there is a change in the open aperture value or the minimum aperture value of the photographing lens. And when the aperture value change determining unit determines that there is a change in the open aperture value or the minimum aperture value, the imaging sensitivity is changed in a direction approaching the exposure value set by the exposure value setting unit. One imaging sensitivity changing unit, an imaging sensitivity range determining unit that determines whether or not the imaging sensitivity changed by the first imaging sensitivity changing unit is within the first imaging sensitivity range, and the changed When the imaging sensitivity is determined not to be within the first imaging sensitivity range by the imaging sensitivity range determination unit, the exposure sensitivity approaches the exposure value set by the exposure value setting unit. The first shutter speed changing means for changing the shutter speed that direction, characterized by having a city.

  According to the present invention, it is possible to provide an imaging apparatus capable of maintaining the exposure by changing the imaging sensitivity and the shutter speed even if the setting is unexpectedly changed due to the change in the aperture value of the lens.

1 is a configuration block diagram of an imaging apparatus as an embodiment of the present invention. (a), (b) is an external view of the imaging device as one Embodiment of this invention. It is a flowchart for maintaining exposure when an open aperture value or a minimum aperture value changes. It is a flowchart at the time of shifting ISO value in order to maintain exposure. It is a flowchart at the time of shifting Tv in order to maintain exposure. FIG. 6 is a GUI image diagram for setting whether exposure is maintained at Tv, ISO value, or exposure is not maintained when Av is changed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of an imaging apparatus 200 as an embodiment of the present invention.

  The lens unit 100 is a lens unit on which an interchangeable photographic lens is mounted. The lens 5 is usually composed of a plurality of lenses, but here, only a single lens is shown for simplicity. The communication terminal 6 is a communication terminal for the lens to communicate with the imaging device side, and the communication terminal 10 is a communication terminal for the imaging device to communicate with the lens side. The lens unit 100 communicates with the microcomputer 40 via the communication terminals 6, 10, controls the aperture 1 via the aperture drive circuit 2 by the internal lens system control circuit 4, and passes through the AF drive circuit 3. The focus is adjusted by displacing the position of the lens 5. Further, the microcomputer 40 acquires the open aperture value and the minimum aperture value of the lens unit 100 via the communication terminals 6 and 10.

  The AE sensor 15 measures the luminance of the subject that has passed through the lens unit 100. The AF sensor 11 outputs defocus amount information to the microcomputer 40. The microcomputer 40 controls the lens unit 100 based on that.

  The quick return mirror 12 is instructed by the microcomputer 40 at the time of exposure, and is raised and lowered by an actuator (not shown). The photographer can confirm the focus and composition of the optical image of the subject obtained through the lens unit 100 by observing the focusing screen 13 via the pentaprism 14 and the finder 16.

  The focal plane shutter 17 is a focal plane shutter that can freely control the exposure time of the image sensor 20 under the control of the microcomputer 40. The optical filter 18 is generally composed of a low-pass filter or the like, and cuts high-frequency components of light entering from the focal plane shutter 17 and guides the subject image to the image sensor 20.

  The image pickup device 20 is an image pickup device in which a CCD, a CMOS, or the like is generally used, and a subject image formed on the image pickup device 20 through the lens unit 100 is photoelectrically converted and captured as an electric signal.

  The AMP circuit 21 amplifies the photographic signal with a gain corresponding to the set photographic sensitivity with respect to the captured electric signal. The A / D conversion circuit 22 converts the analog signal converted into an electric signal by the image sensor 20 into a digital signal.

  The image processing circuit 23 performs filter processing, color conversion processing, and gamma / knee processing on the image data converted into a digital signal by the A / D conversion circuit 22 and outputs the result to the memory controller 27. The image processing circuit 23 also includes a D / A conversion circuit. The image processing circuit 23 converts the image data converted into a digital signal by the A / D conversion circuit 22 and the image data input by the memory controller 27 into an analog signal and outputs the analog signal to the liquid crystal display unit 25 through the liquid crystal drive circuit 24. You can also

  Image processing and display processing by these image processing circuits 23 are switched by the microcomputer 40. Further, the microcomputer 40 performs white balance adjustment based on the color balance information of the photographed image.

  The liquid crystal display unit 25 is a rear monitor for displaying images and shooting information. As shooting information, for example, an aperture value (Av), a shutter speed (Tv), and an imaging sensitivity (ISO) are displayed. Also, a setting value change screen for changing various setting values can be displayed. The display is not limited to a liquid crystal display as long as it displays an image, and may be a display of another system such as an organic EL.

  The memory controller 27 stores unprocessed image data input from the image processing circuit 23 in the buffer memory 26 or stores image processed image data in the recording medium 28. Conversely, image data is fetched from the buffer memory 26 or the recording medium 28 and output to the image processing circuit 23.

  The memory controller 27 stores the image data sent via the external interface 29 in the recording medium 28, and conversely, the image data stored in the recording medium 28 is externally transmitted via the external interface 29. It is also possible to output. Examples of the external interface include interfaces such as USB, IEEE, and HDMI (registered trademark). The recording medium 28 is a removable recording medium such as a memory card. However, it may be a built-in memory. The microcomputer 40 controls the drive timing of the image sensor 20 via the timing control circuit 32.

  The power supply control circuit 35 is a circuit that controls the power supplied from the AC power supply unit 30 or the secondary battery unit 31. In response to an instruction from the microcomputer 40, the power supply control circuit 35 turns on and off the power supply. The power supply control circuit 35 also notifies the microcomputer 40 of information on the current power supply state detected by the power supply state detection circuit 34 and information on the current power supply type detected by the power supply type detection circuit 33.

  The microcomputer 40 controls the focal plane shutter 17 via the shutter control circuit 36.

  The optical filter vibration control circuit 37 is a circuit that vibrates the piezoelectric element 19 connected to the optical filter 18. It vibrates according to the instruction of the microcomputer 40 so that the piezoelectric element is vibrated with predetermined values for the vibration amplitude, vibration time, and vibration axial direction.

  The non-volatile memory 38 is a non-volatile recording medium that stores user-set values such as shutter speed, aperture value, and shooting sensitivity, as well as other data, even when the imaging device is not turned on. can do.

  The volatile memory 39 stores data that is to be temporarily stored, such as the internal state of the imaging apparatus and information on the removable recording medium 28.

  The operation unit 70 is various operation members as an input unit that receives an operation from a user. The operation unit 70 includes at least the following operation units. Release button 201, main electronic dial 202, sub electronic dial 203, power switch 204, protect button 205, menu button 206, delete button 207, enlargement mode button 208, playback instruction button 209, single / multi switching button 210, multi controller 211 .

  The microcomputer 40 is a control unit that controls each unit included in the imaging apparatus 200. The microcomputer 40 executes various processes described later by expanding and executing the program recorded in the nonvolatile memory 38 using the volatile memory 39 as a work memory.

  FIG. 2A is a diagram illustrating an appearance shape from the front of the entire imaging apparatus 200, and FIG. 2B is a diagram illustrating an appearance shape from the back of the entire imaging apparatus 200. Portions common to FIG. 1 are denoted by the same symbols.

  The release button 201 is a button for issuing a shooting preparation instruction and a shooting instruction. By pressing the button halfway, the brightness of the subject is measured or focused. Further, when the button is fully pressed, the shutter is released and an image is taken.

  The main electronic dial 202 is a rotation operation member, and the user sets setting values such as shutter speed and imaging sensitivity by turning the main electronic dial 202. The sub electronic dial 203 is a rotation operation member, and the user sets setting values such as aperture and exposure correction by turning the sub electronic dial 203.

  A power switch 204 is an operation member for turning the power on and off. The protect button 205 is a button for performing processing such as protection and rating on an image stored in a recording medium inside and outside the imaging apparatus. The menu button 206 is a button for displaying various setting screens on the liquid crystal display unit 25. A delete button 207 is a button for instructing deletion of an image stored in a recording medium inside or outside the imaging apparatus.

  The enlargement mode button 208 is a button for giving an instruction to start enlargement mode and an instruction to end enlargement mode in the reproduction state. The reproduction instruction button 209 is a button for causing the liquid crystal display unit 25 to display an image stored in a recording medium inside and outside the imaging apparatus. The distance measuring point selection button 210 is a button for entering a mode for selecting a distance measuring point 213 which is a start point of autofocus and an AF area 212 which is a range where autofocus is performed.

  The multi-controller 211 can be operated in a plurality of directions for setting a distance measuring point that is a start point of autofocus or moving an enlarged frame (enlarged range) in an enlarged image display state. It is an operation member.

[Example 1]
Hereinafter, with reference to FIGS. 3 to 7, a method for maintaining exposure when the open aperture value (release Av) and the minimum aperture value (minimum Av) of the lens according to the first embodiment of the present invention are changed will be described. To do. First, the basic flow of this method will be described with reference to FIGS.

  In step S100, it is determined whether there is a change in the open Av or the minimum Av acquired from the lens unit 100. If there is a change, the process proceeds to step S101, and if there is no change, the process ends.

  In step S101, it is determined whether or not the shooting mode is the manual mode. If the shooting mode is the manual mode, the process proceeds to step S102, and if not, the process ends.

  If it is determined in step S102 that the currently set Av is less than the open Av or greater than the minimum Av, the process proceeds to step S103, and if not, the process ends. In step S103, Bv (Bv1) at the current set value is calculated based on the following equation (A).

Bv1 = Tv1 + setting Av−ISO1 (A)
Tv1 is the currently set shutter speed, and ISO1 is the currently set imaging sensitivity value.

  In step S104, a setting value is acquired as to whether to shift Tv or to shift the ISO value in order to maintain exposure. The setting can be set by selecting from the GUI image screen shown in FIG. When ISO is selected, the ISO value is shifted in order to maintain exposure, and when Tv is selected, Tv is shifted to maintain exposure. If you choose Never, do nothing.

  In step S105, it is determined whether or not it is set to maintain exposure by shifting Tv as a result of reading in step S104. If it is set to maintain exposure by shifting Tv, the process proceeds to step S107. If not, the process proceeds to step S106.

  In step S106, as a result of reading in step S104, it is determined whether or not the setting is to maintain the exposure by shifting the ISO. If the setting is to maintain the exposure by shifting the ISO, the process proceeds to step S108. Proceed, otherwise do nothing.

  In step S107, processing for shifting Tv is performed to maintain exposure. Details will be described later. In step S108, processing for shifting ISO is performed to maintain exposure. Details will be described later.

Next, this method will be specifically described with reference to FIGS. 4, 5, and 7. First, with reference to FIG. 4, a description will be given of a case where the exposure is maintained by shifting the ISO value.
Here, the change in the lens aperture is F4 → 4.5 → 5 → 5.6.
And the control range of the imaging sensitivity of the camera is ISO 1600 → 2000 → 2500 → 3200 → 6400.
In this way, consider a case where ISO 2500 is set when ISO 3200 is set to 1/3 step by step, and more than 1 step.

In step S200, a control ISO value (ISO2) for maintaining exposure is calculated based on the following equation (B-1).
ISO2 = Bv1-open (or minimum) Av-Tv1 (B-1)
Here, when a value between ISO 3200 and 6400 is calculated as ISO2, rounding processing to a close value is performed. For example, when the lens aperture value is F5, when ISO4000 equivalent is calculated as ISO2, ISO3200 is adopted as ISO2. Further, when the lens aperture value is F5.6, when ISO5000 equivalent is calculated as ISO2, ISO6400 is adopted as ISO2. Also, ISO2 before the rounding process is stored and used in the determination of step 202 and step 203.

  In step S201, it is determined whether ISO2 before rounding calculated in step S200 exceeds the ISO threshold value H (ISO_H_TH). If it exceeds, the process proceeds to step S203, and if not, the process proceeds to step S202. When the imaging sensitivity control range is the range illustrated here, ISO 3200 is set as the ISO threshold H.

  In step S202, it is determined whether or not ISO2 before rounding calculated in step S200 is below the ISO threshold L (ISO_L_TH). If it is below, the process proceeds to step S203. If not, ISO2 calculated in step S200 is set as the control ISO value, and exposure is maintained. In contrast to the lens aperture change exemplified here, when the lens aperture changes in a decreasing direction, it may be determined that ISO2 before the rounding process is below the ISO threshold L.

In step S203, control Tv (Tv2) for maintaining exposure is calculated based on the following equation (B-2).
Tv2 = Bv1-open (or minimum) Av + ISO2 (B-2)
At this time, information indicating that the shutter speed has changed from the set value may be displayed on the liquid crystal display unit. For example, display is performed such that the Tv display portion of the liquid crystal display unit blinks or an icon is displayed.

  By setting the ISO value and Tv as described above, when the aperture is changed from F4 to 4.5 → 5 → 5.6, F4.5 and F5 are ISO3200, and F5.6 is ISO6400. Become. When the aperture is F5 or F5.6, exposure is maintained by changing Tv. Thus, the user can take a picture with peace of mind.

  Next, with reference to FIG. 5, the case where the exposure is to be maintained by shifting the shutter speed will be described.

Here, the change in the lens aperture is F4 → 4.5 → 5 → 5.6.
The camera shutter speed control range is 1/2000 → 1/2500 → 1/3200 → 1/4000 → 1/8000.
Thus, consider a case where the shutter speed is set to 1/3200 when 1/3 step up to 1/4000 and 1 step beyond that.

In step S300, a control Tv (Tv2) for maintaining exposure is calculated based on the following equation (C-1).
Tv3 = Bv1-open Av + ISO1 (C-1)
Here, when a value between 1/4000 and 1/8000 is calculated as Tv3, rounding to a close value is performed. For example, if the lens aperture value is F5 and Tv3 equivalent to 1/5000 is calculated, 1/40 is adopted as Tv3. Further, when the lens aperture value is F5.6, when 1/6400 equivalent is calculated as Tv3, 1/8000 is adopted as Tv3. Further, Tv3 before the rounding process is stored and used in the determination in step 302 and step 303.

  In step S301, it is determined whether or not Tv3 before the rounding process calculated in step S300 exceeds the Tv threshold value H (Tv_H_TH). When the control range of the shutter speed is the range exemplified here, 1/4000 is set as the Tv threshold value H.

  In step S302, it is determined whether or not Tv3 before rounding calculated in step S300 is below the Tv threshold value L (Tv_L_TH). If it is below, the process proceeds to step S303. If not lower, Tv3 calculated in step S300 is set as the control Tv, and the exposure is maintained. In contrast to the lens aperture change exemplified here, when the lens aperture changes in a decreasing direction, it may be determined that Tv3 before the rounding process is below the Tv threshold value L.

In step S303, ISO (ISO3) for maintaining exposure is calculated based on the following equation (C-2).
ISO3 = Bv1-open (or minimum) Av-Tv3 (C-2)
At this time, information indicating that the ISO value has changed from the set value may be displayed on the liquid crystal display unit. For example, display is performed such that the Tv display portion of the liquid crystal display unit blinks or an icon is displayed.

  As described above, when the aperture is changed from F4 to 4.5 → 5 → 5.6 by setting the Tv and ISO values, the shutter speed becomes 1/4000 at F4.5 and F5, and F5 .6 is 1/8000. When the aperture is F5 or F5.6, the exposure is maintained by changing the ISO value. Thus, the user can take a picture with peace of mind.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Aperture 5 Lens 17 Focal plane shutter 20 Image pick-up element 25 Liquid crystal display part 40 Microcomputer 70 Operation part

Claims (4)

Exposure value setting means (70) for setting the aperture value, shutter speed, and imaging sensitivity;
Aperture value change determination means (40) for determining whether there is a change in the open aperture value or the minimum aperture value of the taking lens;
The first imaging that changes the imaging sensitivity in a direction approaching the exposure value set by the exposure value setting unit when the aperture value change determination unit determines that the open aperture value or the minimum aperture value has changed. A sensitivity changing means (40);
Imaging sensitivity range determining means (40) for determining whether or not the imaging sensitivity changed by the first imaging sensitivity changing means is within the first imaging sensitivity range;
When the changed imaging sensitivity is determined not to be within the first imaging sensitivity range by the imaging sensitivity range determination unit, the imaging sensitivity range determination unit approaches the exposure value set by the exposure value setting unit. First shutter speed changing means (40) for changing the shutter speed;
An imaging apparatus comprising: The imaging apparatus according to claim 1, further comprising display means (25),
When the shutter speed is changed by the first shutter speed changing unit, information indicating that the shutter speed has been changed is displayed on the display unit. Exposure value setting means (70) for setting the aperture value, shutter speed, and imaging sensitivity;
Aperture value change determination means (40) for determining whether there is a change in the open aperture value or the minimum aperture value of the taking lens;
A second shutter that changes the shutter speed in a direction approaching the exposure value set by the exposure value setting unit when the aperture value change determination unit determines that the open aperture value or the minimum aperture value has changed. Speed changing means (40);
Shutter speed range determining means (40) for determining whether or not the shutter speed changed by the second shutter speed changing means is within the second shutter speed range;
If the changed shutter speed is determined not to be within the second shutter speed range by the shutter speed range determination means, the exposure speed setting means approaches the exposure value set by the exposure value setting means. Second imaging sensitivity changing means (40) for changing imaging sensitivity;
An imaging apparatus comprising: The imaging apparatus according to claim 3, further comprising display means (25),
When the imaging sensitivity is changed by the second imaging sensitivity changing means, information indicating that the imaging sensitivity has been changed is displayed on the display means.