JP2013090146A - Imaging device and control program for imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which a blur degree of an image obtained by cutting out part of a photographed image is different from a blur degree of an image obtained by photographing the same range as the cutout image using a lens with a long focal distance.SOLUTION: An imaging device comprises: an image sensor in which a plurality of pixels are two-dimensionally arranged; a selection unit that selects a pixel range corresponding to image data to be generated from the plurality of pixels as a selected pixel range; and a control unit that shifts a program diagram specifying an exposure value in imaging on the basis of the selected pixel range selected by the selection unit.

Description

  The present invention relates to an imaging apparatus and a control program for the imaging apparatus.

In recent years, a camera has a function of not only recording a captured image as it is, but also cutting out and recording a part of the captured image.
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP-A-10-177737

  An image obtained by cutting out a part of the captured image has a smaller angle of view than the captured image itself, and an image similar to that obtained when a lens with a long focal length is used can be obtained. However, when shooting with the same aperture value, an image shot using a lens with a long focal length so as to have the same angle of view as that of the clipped image and a cut-out image of a part of the shot image It is different from the bokeh condition.

  The imaging device according to the first aspect of the present invention selects an image sensor in which a plurality of pixels are two-dimensionally arranged and a range of pixels corresponding to image data to be generated as a selected pixel range from the plurality of pixels. And a control unit that shifts a program diagram that defines the exposure value at the time of imaging based on the selected pixel range selected by the selection unit.

  An imaging device control program according to the second aspect of the present invention is an imaging device control program including an imaging device in which a plurality of pixels are two-dimensionally arranged, and image data generated from the plurality of pixels. A selection step of selecting a pixel range corresponding to the selection pixel range, and a control step of shifting a program diagram defining an exposure value at the time of imaging based on the selection pixel range selected by the selection step. Let it run.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is an external appearance perspective view of the interchangeable lens and camera main body which concern on this embodiment. It is a rear view of the camera main body which concerns on this embodiment. 1 is a system configuration diagram of a single-lens reflex camera according to the present embodiment. It is a figure explaining the imaging range of an image sensor. It is a figure explaining depth of field. It is a figure which shows an example of the depth of field in the case of shooting distance L = 3000 mm. The program diagram in program mode is shown. The program diagram in portrait mode is shown. The program diagram in sport mode is shown. The program diagram in landscape mode is shown. The imaging processing flow of this embodiment is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is an external perspective view of an interchangeable lens 20 and a camera body 30 of a single-lens reflex camera 10 according to the present embodiment. The interchangeable lens 20 includes a lens mount 21, and the camera body 30 includes a camera mount 31. When the lens mount 21 and the camera mount 31 are engaged and the interchangeable lens 20 and the camera body 30 are integrated, the interchangeable lens 20 and the camera body 30 function as the single-lens reflex camera 10.

  Along the arrow 12 parallel to the optical axis 11, the lens mount 21 is brought close to the camera mount 31 and brought into contact so that the lens index 22 and the body index 32 face each other. Further, the interchangeable lens 20 is rotated in the direction of the arrow 13 while maintaining the contact between the mount surface of the lens mount 21 and the mount surface of the camera mount 31. Then, the lock mechanism by the lock pin 33 operates, and the interchangeable lens 20 is fixed to the camera body 30. In this state, a connection is established between the communication terminal on the interchangeable lens 20 side and the communication terminal on the camera body 30 side, and communication such as a control signal can be performed.

  When the interchangeable lens 20 is separated from the camera body 30, the user depresses the attach / detach button 34 to retract the lock pin 33 interlocked with the attach / detach button 34 from the mount surface of the camera mount 31 to release the lock. Then, the interchangeable lens 20 is rotated and pulled apart in the reverse procedure of the mounting.

  The interchangeable lens 20 forms an image of a subject light beam on a light receiving surface of an image sensor provided in the camera body 30. A plurality of interchangeable lenses 20 are prepared as products of various specifications having different image circle sizes, focal lengths, open F values, and the like on the light receiving surface of the image sensor. Each of these interchangeable lenses 20 includes a lens mount 21 that engages with the camera mount 31. If the camera body 30 adopts the camera mount 31, a different camera body 30 can be mounted. it can.

  The camera body 30 includes a release button 35. The release button 35 is formed of a push button that can be detected in two steps in the pushing direction. The user can photograph the subject by depressing the release button 35.

  FIG. 2 is a rear view of the camera body 30 according to the present embodiment. As shown in FIG. 2, a cross key 37 as an operation member is provided in the vicinity of the display unit 36. The user can move the selection range of the menu item displayed on the display unit 36 up, down, left, and right by operating the cross key 37. An enter button 38 is provided at the center of the cross key 37. The user confirms the selection with the cross key 37 by depressing the determination button 38.

  For example, in a state where the imaging range setting menu screen is displayed as shown in FIG. 2, the user can move the active frame 39 among the menu items by operating the cross key 37 up and down. A plurality of pixel ranges are presented as selectable menu items. When the user moves the active frame 39 to the intended location, the user presses the enter button 38 to instruct the setting of the selected menu item. The radio button 40 is turned on as the determination button 38 is pressed, and the user can visually recognize his / her selection.

  As shown in FIG. 2, a seesaw switch 41 as an operation member is provided in the vicinity of the cross key 37. The user can instruct zooming by operating the seesaw switch 41. The zoom process will be described later.

  FIG. 3 is a system configuration diagram of the single-lens reflex camera according to the present embodiment. The subject image passes through the optical system along the optical axis 11 and forms on the light receiving surface of the image sensor 133. The optical system includes a focus lens 23, a zoom lens 24, a diaphragm 25, and the like. The optical system is controlled by the lens system control unit 120. For example, the lens system control unit 120 controls a motor that moves the focus lens 23 and a motor that moves the zoom lens 24 via the motor drive circuit 122. The lens system control unit 120 drives the diaphragm 25 via the diaphragm drive circuit 123.

  The lens system control unit 120 is connected to the camera system control unit 130 via the lens mount contact 121 and the camera mount contact 131, and controls the interchangeable lens 20 and the camera body 30 in cooperation with each other while performing communication. The lens mount contact 121 and the camera mount contact 131 include a communication terminal on the interchangeable lens 20 side and a communication terminal on the camera body 30 side, respectively.

  The image sensor 133 is an element that photoelectrically converts an optical image that is a subject image that is incident through the optical system. For example, a CCD or CMOS sensor is used. The shutter 134 opens only during the exposure time at the time of photographing so that light is incident on the image sensor 133 only at the time of photographing, and blocks the light at other times. The subject image photoelectrically converted by the image sensor 133 is converted from an analog signal to a digital signal by the A / D converter 135. The subject image converted into the digital signal is sequentially processed as image data.

  The image data converted into a digital signal by the A / D converter 135 is delivered to the image processing unit 136. The image processing unit 136 converts the image data into image data of a standardized image format according to the set shooting mode and an instruction from the user. For example, when a JPEG file is generated as a still image, image processing such as color conversion processing, gamma processing, and white balance processing is performed, and then adaptive discrete cosine conversion is performed to perform compression processing. When an MPEG file is generated as a moving image, compression processing is performed by applying intra-frame coding and inter-frame coding to the generated frame images as continuous still images.

  When the amount of image data input from the A / D converter 135 to the image processing unit 136 exceeds the processing capability of the image processing unit 136, unprocessed image data is temporarily stored in the internal memory 138 under the control of the memory control unit 137. Remembered. That is, the internal memory 138 serves as a buffer memory that waits for the order of image processing when image data is continuously generated at high speed in continuous shooting and moving image shooting. The internal memory 138 is a random access memory that can be read and written at high speed, and for example, a DRAM, an SRAM, or the like is used. The internal memory 138 also serves as a work memory in image processing and compression processing performed by the image processing unit 136. The internal memory 138 has a sufficient memory capacity corresponding to these roles. The memory control unit 137 controls how much memory capacity is allocated to what work.

  Still image data and moving image data processed by the image processing unit 136 are recorded in the recording unit 141 of the recording medium from the internal memory 138 via the external device IF 140 under the control of the memory control unit 137. The recording medium is a non-volatile memory that is configured by a flash memory or the like and is detachable from the camera body 30. Also, shooting information such as the number of pixels, the compression mode, the model name of the camera body 30, lens information, shooting mode, aperture value, shutter speed, and the like is recorded in the recording unit 141 in association with the image data.

  The image data processed by the image processing unit 136 generates display image data in parallel with the image data processed for recording. The generated display image data is displayed on the display unit 36 under the control of the display control unit 139. Regardless of the presence or absence of recording, if image data for sequential display is generated and displayed on the display unit 36, a live view can be realized as an electronic viewfinder function. Various menu items related to various settings of the single-lens reflex camera 10 can be displayed on the display unit 36 under the control of the display control unit 139 with or without displaying an image.

  The single-lens reflex camera 10 is controlled directly or indirectly by the camera system control unit 130 including each element in the image processing described above. The camera system control unit 130 includes a system memory 132. The system memory 132 is an electrically erasable / recordable nonvolatile memory, and is configured by, for example, an EEPROM (registered trademark). The system memory 132 records constants, variables, programs, and the like necessary for the operation of the single lens reflex camera 10 so that they are not lost even when the single lens reflex camera 10 is not operated. Further, the system memory 132 records a program diagram for defining an exposure value at the time of shooting for each shooting mode. The camera system control unit 130 develops constants, variables, programs, and the like in the internal memory 138 as appropriate, and uses them for controlling the single-lens reflex camera 10.

  The camera body 30 includes a plurality of operation members such as a release button 35 that accepts an operation from the user and a cross key 37. The operation detection unit 144 detects that these operation members have been operated, and controls the camera system. The detection result is output to the unit 130. The camera system control unit 130 performs an operation according to the detected operation.

  The camera system control unit 130 executes AF, AE, and the like, which are shooting preparation operations, by detecting that SW1 is turned on, which is the first depression of the release button 35. Then, the camera system control unit 130 executes the subject image acquisition operation by the image sensor 133 by detecting the ON of the SW2 that is the second depression of the release button 35.

  The camera body 30 receives power supply from the power source 143. The power supply control unit 142 communicates with the power supply 143 to detect remaining power, monitor power supply, and supply power. The power source 143 includes a secondary battery, a household AC power source, and the like. Further, power is supplied to the interchangeable lens 20 through the lens mount contact 121 and the camera mount contact 131.

  The photometric sensor 145 is provided in the vicinity of the viewfinder and detects the brightness of the subject. The exposure control unit 146 analyzes the photometric data detected by the photometric sensor 145 and calculates an exposure value. The exposure control unit 146 outputs a control signal for the diaphragm 25 to the lens system control unit 120 via the camera system control unit 130 according to the calculated exposure value. Further, the exposure control unit 146 outputs a control signal for setting a read gain corresponding to the ISO sensitivity to the image sensor 133 according to the exposure value. Further, the exposure control unit 146 outputs a control signal for setting the shutter speed to the shutter 134.

  The exposure control unit 146 acquires a program diagram to be described later from the system memory 132 according to the shooting mode selected by the user. Then, the exposure control unit 146 calculates an exposure value with reference to the program diagram.

  The focus control unit 147 executes autofocus control by switching between the phase difference AF method or the contrast AF method according to user settings, and controls the drive of the focus lens 23 to the lens system control unit 120 via the camera system control unit 130. Output a signal.

  The zoom control unit 148 performs zoom processing according to the operation of the seesaw switch 41 by the user. Specifically, when the user operates the seesaw switch 41 to give a zoom instruction, the zoom control unit 148 outputs a drive control signal for the zoom lens 24 to the lens system control unit 120, and an optical zoom by driving the zoom lens 24. Execute. The zoom control unit 148 stops driving the zoom lens 24 and cooperates with the image processing unit 136 when the user further operates the seesaw switch 41 to give a zoom instruction while the optical zoom is at the maximum magnification. The electronic zoom by image processing is executed.

  FIG. 4 is a diagram for explaining the imaging range of the imaging device, and is a diagram facing the imaging device 133 along the optical axis 11 from the camera mount 31 side. The imaging range is a range of pixels to be imaged among a plurality of pixels of the imaging element 133. In the present embodiment, three pixel ranges are defined in advance as the imaging range.

  The first imaging range is a pixel range of the effective pixel area of the imaging element 133. In this embodiment, the pixel range of the effective pixel region of the image sensor 133 is 36 mm × 24 mm, which is about the same as the size of a 35 mm plate film, and a diagonal length of about 43 mm. The pixel range of this effective pixel region is expressed as FX size.

  The second imaging range is a first pixel range 151 constituted by 24 mm × 16 mm and a diagonal length of about 29 mm, which are approximately the same as the C size of the APS plate film smaller than the FX size. This first pixel range 151 is represented as DX size. The third imaging range is a second pixel range 152 configured by 17.3 m × 13 mm smaller than the DX size and a diagonal length of about 21.6 mm. This second pixel range 152 is represented as BX size.

  The user can determine the pixel range of the imaging element 133 corresponding to the image data generated by the image processing unit 136 from the first imaging range, the second imaging range, and the third imaging range. In the present embodiment, the pixel range of the image sensor 133 corresponding to the imaging range determined by the user is referred to as a selected pixel range. Specifically, the camera system control unit 130 selects the imaging range in which the radio button 40 is turned on as the selected pixel range on the menu screen for imaging range setting in FIG.

  When the image sensor 133 photoelectrically converts the subject image in the selected pixel range, the image processing unit 136 can generate image data corresponding to the selected pixel range. Further, the image processing unit 136 may crop image data corresponding to the selected pixel range among the image data output from the A / D converter 135.

Next, the relationship between the selected pixel range and the degree of blur of the captured image will be described. FIG. 5 is a diagram illustrating the depth of field. The depth of field is the range of the depth of the subject that is determined to be in focus in the observed captured image. The depth of field T is expressed by the following equation using the front depth of field Tf and the rear depth of field Tr. Tf = δFL ² / (f ² + δFL) (1), Tr = δFL ² / (f ² −δFL) (2), T = Tf + Tr = δFL ² / (f ² + δFL) + δFL ² / (F ² −δFL) [3]. Here, δ: allowable confusion circle diameter, F: aperture value, L: photographing distance, f: focal length.

  The light emitted from the point light source within the depth of field T is imaged as a circle having a diameter within the allowable confusion circle diameter δ on the light receiving surface of the image sensor 133. The allowable circle of confusion circle δ is the diameter of a circle of confusion having the maximum size on the light receiving surface that can be visually recognized as a point when observed as a captured image. The allowable circle of confusion diameter δ is generally a value obtained by dividing the diagonal length D of the selected pixel range by a constant 1000 to 1500. Therefore, the permissible circle of confusion δ is proportional to the diagonal length D of the selected pixel range.

  When shooting at the same angle of view, the focal length f is proportional to the diagonal length D of the selected pixel range. For example, when the selected pixel range is the DX size and the focal length f = 50 mm, the angle of view is the selected pixel range is the FX size and the focal length f = 50 mm × (the diagonal length ratio of the FX size to the DX size is 1 .5) = same as the angle of view when 75 mm.

As described above, the permissible circle of confusion δ and the focal length f are proportional to the diagonal length D of the selected pixel range. When this proportional relationship is expressed by δ = aD and f = bD and substituted into the above equation [3], the depth of field T is expressed by the following equation. ^{T = aFL 2 / (b 2} D + aFL) + aFL 2 / (b 2 D-aFL) ··· [4].

  Therefore, when photographing with the same angle of view while keeping the aperture value F and the photographing distance L constant, the depth of field T becomes deeper as the diagonal length D of the selected pixel range is shorter, that is, the smaller the selected pixel range is. As the depth of field T becomes deeper, the range of the observed depth increases and the blur is reduced. For this reason, when shooting with the aperture value F and the shooting distance L fixed and the focal length f adjusted so that the angle of view is equal, a shot image with a small selected pixel range is compared with a shot image with a large selected pixel range. There is little blur.

Here, the aperture value F is made proportional to the diagonal length D of the selected pixel range in the same manner as the permissible circle of confusion δ and the focal length f. When this proportional relationship is expressed by F = cD and substituted into the above-described equation [4], the depth of field T is expressed by the following equation. ^{T = acL 2 / (b 2} + acL) + acL 2 / (b 2 -acL) ··· [5].

  As can be seen from Equation [5], if the shooting distance L is constant, the depth of field T is constant even if the diagonal length ratio D of the selected pixel range changes. Therefore, if the shooting distance L is fixed and the aperture value F is proportional to the diagonal line length D and the focal length f is adjusted so that the angle of view is equal, the shot image and the selected pixel range having a small selected pixel range can be obtained. This is equivalent to a large-capacity photographed image.

  FIG. 6 is a diagram illustrating an example of the depth of field when the shooting distance L is 3000 mm. Using a value satisfying the constant 1000-1500 of the allowable confusion circle diameter δ described above, the allowable confusion circle diameter δ of FX size is 0.03 mm, allowable confusion circle diameter δ of DX size is 0.02 mm, and allowable confusion of BX size. The circle diameter δ is set to 0.015 mm.

  In the table of FIG. 6, three states in the case where the selected pixel range is the FX size are indicated by a first column 161, a second column 162, and a third column 163. The value at the lower end of the first column 161 indicates the depth of field T when the focal length f = 50 mm and the aperture value F = 5.6. The value at the lower end of the second column 162 indicates the depth of field T when the focal length f = 75 mm and the aperture value F = 5.6. The value at the lower end of the third column 163 indicates the depth of field T when the focal length f = 100 mm and the aperture value F = 5.6.

  In the table of FIG. 6, two states in the case where the selected pixel range is the DX size are indicated by a fourth column 164 and a fifth column 165. The value at the lower end of the fourth column 164 indicates the depth of field T when the focal length f = 50 mm and the aperture value F = 5.6. The value at the lower end of the fifth column 165 indicates the depth of field T when the focal length f = 50 mm and the aperture value F = 3.8.

  Furthermore, in the table of FIG. 6, two states when the selected pixel range is the BX size are indicated by a sixth column 166 and a seventh column 167. The value at the lower end of the sixth column 166 indicates the depth of field T when the focal length f = 50 mm and the aperture value F = 5.6. The value at the lower end of the seventh column 167 indicates the depth of field T when the focal length f = 50 mm and the aperture value F = 2.8.

  Here, the captured image in the state of the second column 162 and the captured image in the state of the fourth column 164 are compared. As described above, the angle of view when the selected pixel range is DX size and the focal length f = 50 mm is the same as the angle of view when the selected pixel range is FX size and the focal length f = 75 mm. is there. Therefore, the shooting range in the state of the second column 162 is equivalent to the shooting range in the state of the fourth column 164. Since the aperture value F in the state of the second column 162 and the aperture value F in the state of the fourth column 164 are both 5.6, the depth of field T in the state of the fourth column 164 is the second column. It is deeper than the depth of field T in the state of 162. Therefore, the image shot in the state of the fourth row 164 has the same shooting range but less blur than the image shot in the state of the second row 162.

  Next, in the state of the fifth column 165, the aperture value F = 5.6 in the state of the fourth column 164 is multiplied by the diagonal length ratio of DX size to the FX size of 0.67 to set the aperture value F to 3.8. And the captured image in the state of the second column 162 are compared. As described above, the angle of view when the selected pixel range is DX size and the focal length f = 50 mm is the same as the angle of view when the selected pixel range is FX size and the focal length f = 75 mm. is there. Therefore, the shooting range in the state of the second column 162 is equivalent to the shooting range in the state of the fifth column 165. By making the aperture value F proportional to the diagonal length, the depth of field T in the state of the second column 162 and the depth of field T in the state of the fifth column 165 become equal. Therefore, the image captured in the state of the fifth column 165 has the same imaging range and the same degree of blur as compared to the image captured in the state of the second column 162.

  If the depths of field of both captured images do not completely match, such as the depth of field T in the state of the second column 162 and the depth of field T of the fifth column 165, the depth of field As long as the difference is within a predetermined allowable range, the blurring details of both captured images may be the same. For example, the allowable range may be defined as 5% of the depth of field of one of the reference captured images.

  The same applies when the selected pixel range is BX size. The captured image in the state of the third column 163 and the captured image in the state of the sixth column 166 are compared. The angle of view when the selected pixel range is BX size and the focal length f = 50 mm is the diagonal length ratio 2 = 100 mm of the FX size with respect to the focal length f = 50 mm × BX size. It is equivalent to the angle of view in some cases. Therefore, the shooting range in the state of the third column 163 is equivalent to the shooting range in the state of the sixth column 166. Since the aperture value F in the state of the third column 163 and the aperture value F in the state of the sixth column 166 are both 5.6, the depth of field T in the state of the sixth column 166 is the third column. It is deeper than the depth of field T in the state of 163. Therefore, the image shot in the state of the sixth column 166 has the same shooting range but less blur than the image shot in the state of the third column 163.

  Next, in the state of the seventh column 167, the aperture value F = 5.6 in the state of the sixth column 166 is multiplied by the diagonal length ratio 0.5 of the BX size to the FX size and 2.8 is set as the aperture value F. And the captured image in the state of the third column 163 are compared. As described above, the angle of view when the selected pixel range is the BX size and the focal length f = 50 mm is the same as the angle of view when the selected pixel range is the FX size and the focal length f = 100 mm. is there. Therefore, the shooting range in the state of the third column 163 is equivalent to the shooting range in the state of the seventh column 167. By making the aperture value F proportional to the diagonal length, the depth of field T in the state of the third column 163 and the depth of field T in the state of the seventh column 167 are equal. Therefore, the image captured in the state of the seventh row 167 has the same shooting range and the same degree of blur as the image captured in the state of the third column 163.

  The exposure control in this embodiment will be described. FIG. 7 shows a program diagram in the program mode. The program diagram defines the exposure value at the time of shooting according to the shooting mode. The exposure value is defined by a combination of the aperture value, shutter speed, and ISO sensitivity. The program diagram in the present embodiment is for ISO 100. The program mode is a shooting mode that automatically sets the aperture value F and the shutter speed.

  In the graph of FIG. 7, the vertical axis indicates the aperture value F, the horizontal axis indicates the shutter speed, and the oblique line indicates EV which is a value indicating the brightness of the subject. The lower limit value of the aperture value F of the single-lens reflex camera 10 according to the present embodiment is 1.4, and the upper limit value is 16. In addition, the upper limit value of the shutter speed of the single-lens reflex camera 10 according to the present embodiment is 1/8000 seconds, and the lower limit value is 30 seconds. A diagram indicated by a solid line in FIG. 7 is a reference program diagram defined in advance according to the FX size, which is the pixel range of the effective pixel region of the image sensor 133. The reference program diagram is recorded in the system memory 132.

  When the program mode is selected as the shooting mode, first, the exposure control unit 146 reads this reference program diagram from the system memory 132. Next, the exposure control unit 146 calculates the EV by analyzing the photometric data detected by the photometric sensor 145, and extracts the aperture value and shutter speed at the intersection of the calculated EV and the reference program diagram in the graph of FIG. To do. Then, the exposure control unit 146 executes exposure control by outputting a control signal for operating the diaphragm 25 and the shutter 134 respectively with the extracted aperture value and shutter speed.

  For example, when EV is 12, the aperture value F = 5.6 at the intersection of the oblique line indicating that EV is 12 and the reference program diagram in the graph of FIG. 7 and the shutter speed 1/125 seconds are selected. Then, the exposure control unit 146 outputs a control signal for setting the aperture value of the aperture 25 to 5.6 and a control signal for setting the shutter speed of the shutter 134 to 1/125 seconds.

  A user who normally selects the FX size as the selected pixel range and captures the image in the program mode recognizes the degree of blurring of the FX-size captured image captured with the exposure value corresponding to the above-described reference program diagram. Assume that the user changes the selected pixel range from the FX size to the DX size and shoots in the program mode for the telephoto effect. If the reference program diagram is used regardless of the selected pixel range, even if the selected pixel range is changed from the FX size to the DX size, if the EV is the same value, the aperture value F is also the same value. For example, as shown in FIG. 7, if EV is 12, the aperture value F is 5.6 for both the FX size and the DX size.

  Therefore, as described with reference to FIGS. 5 and 6, the depth of field of the DX size captured image is the depth of field of the FX size captured image having the same angle of view as the DX size captured image. Become deeper. Therefore, a user who normally selects the FX size as the selected pixel range and shoots in the program mode feels that the degree of blur of the DX-size captured image is different from what he intended.

  Therefore, when the DX size is selected as the selected pixel range, the exposure control unit 146 shifts the reference program diagram and uses the shifted program diagram. Specifically, the exposure control unit 146 shifts the reference program diagram so that the aperture value F becomes a value obtained by multiplying the diagonal size ratio of DX size to FX size by 0.67. The diagram indicated by the broken line in FIG. 7 is a program diagram used when the DX size is selected as the selected pixel range. A program diagram used when the DX size is selected as the selected pixel range is referred to as a DX program diagram.

  If the above-mentioned reference program diagram is used when the selected pixel range is FX size, and the above-mentioned DX program diagram is used when the selected pixel range is DX size, the aperture value F is the selected pixel when EV is the same value. The value is proportional to the diagonal length D of the range. Further, the shutter speed corresponding to the aperture value F is selected according to the program diagram. For example, as shown in FIG. 7, when EV is 12, if the selected pixel range is FX size, aperture value F = 5.6 and shutter speed = 1/125 seconds are selected, and the selected pixel range is DX size. If there is, the aperture value F = 5.6 × 0.67 = 3.8 and the shutter speed = 1/300 seconds are selected. When the aperture value is discretely defined and the aperture value F selected in accordance with the program diagram does not match the discrete specified value, the discrete values existing in the vicinity of the selected aperture value F are shown. A specific specified value is used as the aperture value F instead.

  Therefore, as described with reference to FIGS. 5 and 6, the depth of field of the DX-sized captured image is the same as the depth of field of the FX-sized captured image having the same angle of view as the DX-sized captured image. It becomes equivalent. Therefore, a user who normally selects the FX size as the selected pixel range and shoots in the program mode does not feel uncomfortable because the degree of blur of the DX-size captured image is the same as that intended.

  Similarly, when the BX size is selected as the selected pixel range, the exposure control unit 146 uses the reference program diagram so that the aperture value F becomes a value obtained by multiplying the diagonal length ratio of 0.5 between the FX size and the BX size. To shift. The program diagram indicated by the dotted line in FIG. 7 is a program diagram used when the BX size is selected as the selected pixel range. A program diagram used when the BX size is selected as the selected pixel range is referred to as a BX program diagram.

  By using the above-mentioned reference program diagram when the selected pixel range is FX size and using the above-mentioned BX program diagram when the selected pixel range is BX size, the BX size is the same as the above-described DX size. The depth of field of the captured image is equal to the depth of field of the FX size captured image having the same angle of view as the BX size captured image. Therefore, a user who normally selects the FX size as the selected pixel range and shoots in the program mode does not feel uncomfortable because the degree of blur of the BX size captured image is the same as that intended.

  When the above-mentioned reference program diagram is used when the selected pixel range is FX size, and when the above-mentioned BX program diagram is used when the selected pixel range is BX size, the aperture value F is selected when the EV is the same value. The value is proportional to the diagonal length D of the range. Further, the shutter speed corresponding to the aperture value F is selected according to the program diagram. For example, as shown in FIG. 7, when EV is 12, if the selected pixel range is FX size, aperture value F = 5.6 and shutter speed = 1/125 seconds are selected, and the selected pixel range is BX size. If there is, aperture value F = 5.6 × 0.5 = 2.8 and shutter speed = 1/500 seconds are selected.

  Note that when the reference program diagram is shifted as it is, the exposure control unit 146 defines the position as the lower limit value 1.4 when there is a position that is lower than the lower limit value 1.4 of the aperture value F. In the DX program diagram of FIG. 7, a location where EV is about 6.7 or less and a location where EV is 8 or less in the BX program diagram are defined as the lower limit value 1.4. Further, when the reference program diagram is shifted as it is, the exposure control unit 146 defines the location as the upper limit value 1/8000 seconds when there is a location exceeding the upper limit value 1/8000 seconds of the shutter speed. In the BX program diagram of FIG. 7, the portion where EV is 20 or more is defined as the upper limit value 1/8000 seconds.

  In the embodiment of FIG. 7 described above, the exposure control unit 146 makes the ISO sensitivity constant and shifts the shutter speed with the shift of the aperture value F in the program diagram. However, the ISO sensitivity can be changed. Specifically, the exposure control unit 146 makes the shutter speed constant and shifts the ISO sensitivity with the shift of the aperture value F. For example, the exposure control unit 146 shifts the ISO sensitivity from 100 to 50 as the shutter speed is set to 1/125 seconds and the aperture value F is shifted from 5.6 to 4.

  The exposure control unit 146 can also shift both the shutter speed and the ISO sensitivity as the aperture value F of the program diagram is shifted. For example, the exposure control unit 146 shifts the shutter speed from 1/125 seconds to 1/60 seconds and shifts the ISO sensitivity from 100 to 25 as the aperture value F is shifted from 5.6 to 4.

  FIG. 8 shows a program diagram in the portrait mode. The portrait mode is a photographing mode in which the aperture value F is set to be small so that the background is blurred and the subject is emphasized. Similar to the above-described embodiment of FIG. 7, the reference program diagram indicated by the solid line is shifted to define the DX program diagram indicated by the broken line and the BX program diagram indicated by the dotted line. When the reference program diagram is shifted as it is, the exposure control unit 146 sets the position to the upper limit value 1/8000 seconds when there is a position exceeding the upper limit value 1/8000 seconds of the shutter speed. In the DX program diagram of FIG. 8, the location where EV is about 14.7 or more and the location where EV is 14 or more in the BX program diagram is defined as an upper limit value of 1/8000 seconds.

  FIG. 9 shows a program diagram in the sport mode. The sport mode is a shooting mode in which the shutter speed is set closer to a high speed so that even a moving subject is less likely to blur. Similar to the above-described embodiment of FIG. 7, the reference program diagram indicated by the solid line is shifted to define the DX program diagram indicated by the broken line and the BX program diagram indicated by the dotted line. Note that when the reference program diagram is shifted as it is, the exposure control unit 146 defines the position as the lower limit value 1.4 when there is a position that is lower than the lower limit value 1.4 of the aperture value F. In the DX program diagram of FIG. 9, a location where EV is about 11.4 or less and a location where EV is about 12.4 or less in the BX program diagram are defined as the lower limit value 1.4.

  Further, when the reference program diagram is shifted as it is, the exposure control unit 146 sets the position to the upper limit value 1/8000 seconds when there is a position exceeding the upper limit value 1/8000 seconds of the shutter speed. In the DX program diagram of FIG. 9, the location where EV is about 19.2 or more and the location where EV is 17 or more in the BX program diagram is defined as an upper limit value of 1/8000 seconds.

  FIG. 10 shows a program diagram in the landscape mode. The landscape mode is a shooting mode in which the aperture value F is set large so that the subject is in focus from near to far. Similar to the above-described embodiment of FIG. 7, the reference program diagram indicated by the solid line is shifted to define the DX program diagram indicated by the broken line and the BX program diagram indicated by the dotted line. When the reference program diagram is shifted as it is, the exposure control unit 146 sets the position to the upper limit value 1/8000 seconds when there is a position exceeding the upper limit value 1/8000 seconds of the shutter speed. In the DX program diagram of FIG. 10, the location where EV is about 19.6 or more and the location where EV is 18.6 or more in the BX program diagram are defined as the upper limit value 1/8000 seconds.

  FIG. 11 shows a shooting process flow of the present embodiment. This flow is started, for example, when the power source of the camera body 30 is turned on. In the present embodiment, the exposure control unit 146 executes the processing of this flow in cooperation with the camera system control unit 130.

  In step S101, the exposure control unit 146 acquires information on the shooting mode selected by the user. The shooting modes are the above-described program mode, portrait mode, sports mode, landscape mode, and the like. The camera system control unit 130 detects the shooting mode selected by the user and stores the shooting mode information in the system memory 132. Then, the exposure control unit 146 acquires shooting mode information from the system memory 132. In step S102, the exposure control unit 146 acquires a program diagram corresponding to the shooting mode from the system memory 132. For example, when the program mode is selected as the shooting mode, the exposure control unit 146 acquires the reference program diagram described with reference to FIG.

  In step S103, the exposure control unit 146 determines whether or not the shooting mode selected by the user is a mode for prohibiting the shift of the program diagram. Specifically, the exposure control unit 146 determines that the manual exposure mode and the aperture priority mode in which the user manually determines the aperture value F are the modes for prohibiting the shift of the program diagram. If the shooting mode is a mode for prohibiting the shift of the program diagram, the process proceeds to step S108, and if not, the process proceeds to step S104.

  In step S104, the camera system control unit 130 selects a pixel range of the image sensor 133 corresponding to the image data generated by the image processing unit 136 as a selected pixel range in accordance with a user operation. For example, the camera system control unit 130 selects an imaging range in which the user turns on the radio button 40 as a selected pixel range on the imaging range setting menu screen of FIG.

  In step S105, the exposure control unit 146 determines whether or not the selected pixel range is a reference pixel range. The reference pixel range is a pixel range corresponding to the program diagram acquired in step S102. For example, when the reference program diagram described with reference to FIG. 7 is acquired, the FX size becomes the reference pixel range. When the selected pixel range is the reference pixel range, the process proceeds to step S108, and when the selected pixel range is not the reference pixel range, the process proceeds to step S106.

  In step S106, the exposure control unit 146 calculates the shift amount of the program diagram acquired in step S102. For example, as described with reference to FIG. 7, the exposure control unit 146 calculates the diagonal length ratio of the selected pixel range with respect to the reference pixel range. In step S107, the exposure control unit 146 shifts the program diagram acquired in step S102 using the shift amount calculated in step S106. For example, as described with reference to FIG. 7, the exposure control unit 146 shifts the reference program diagram by multiplying the aperture value F by the diagonal length ratio of the selected pixel range to the reference pixel range.

  In step S <b> 108, the camera system control unit 130 detects whether or not SW <b> 1 that is the first-stage depression of the release button 35 is turned on. The process waits in step S108 until SW1 is turned on, and when it is detected that SW1 is turned on, the process proceeds to step S109.

  In step S109, the exposure control unit 146 acquires photometric data detected by the photometric sensor 145. In step S110, the exposure control unit 146 determines an exposure value at the time of shooting according to the photometric data and the program diagram. In this case, the exposure control unit 146 uses the shifted program diagram when the program diagram is shifted in step S107. The details of the exposure value determination process are as described with reference to FIG.

  In step S <b> 111, the camera system control unit 130 detects whether SW <b> 2, which is the second-stage depression of the release button 35, is turned on. If it is detected that SW2 is turned on, the process proceeds to step S109. If it is not detected that SW2 is turned on within a certain period of time, for example, within a few seconds after SW1 is turned on, the process proceeds to step S114.

  In step S112, the exposure control unit 146 performs exposure control according to the exposure value determined in step S110. Details of the exposure control processing are as described with reference to FIG. In step S113, the image processing unit 136 acquires the output of the image sensor 133 via the A / D converter 135 and converts it into image data in a standardized image format. The image data processed by the image processing unit 136 is recorded in the recording unit 141.

  In step S114, the camera system control unit 130 determines whether or not the user has changed the shooting mode. For example, the camera system control unit 130 determines whether the user has selected another shooting mode on the shooting mode menu screen. If the user has changed the shooting mode, the process proceeds to step S102. If the user has not changed the shooting mode, the process proceeds to step S115. In step S115, the camera system control unit 130 determines whether the power of the camera body 30 is turned off. If the power source of the camera body 30 remains on, the process proceeds to step S104. If the power source of the camera body 30 is turned off, this flow ends.

  In the above embodiment, the pixel range of the imaging element 133 corresponding to the image data generated by the image processing unit 136 is selected from the three imaging ranges of the FX size, the DX size, and the BX size, but is not limited thereto. The user may be allowed to specify an arbitrary pixel range in the effective pixel region of the image sensor 133 as the above-described selected pixel range. In this case, the exposure control unit 146 calculates the diagonal length D of the pixel range specified by the user, and determines the exposure value as described above.

  In addition, the camera system control unit 130 may select the pixel range of the image sensor 133 corresponding to the image data cut by the electronic zoom as the selected pixel range. Specifically, in response to the zoom instruction of the seesaw switch 41 by the user, the zoom control unit 148 drives the zoom lens 24 via the camera system control unit 130 to execute optical zoom. Then, when the zoom instruction of the seesaw switch 41 is further made in a state where the optical zoom is at the maximum magnification, the zoom control unit 148 stops driving the zoom lens 24 and starts electronic zoom.

  In the electronic zoom, the image data corresponding to the pixel at the center of the image sensor 133 is cut out and enlarged by interpolation. When the user's instruction for electronic zoom is completed, the camera system control unit 130 selects the pixel range of the image sensor 133 corresponding to the image area cut out by the electronic zoom as the selected pixel range. Then, the exposure control unit 146 calculates the diagonal length D of this pixel range, and determines the exposure value as described above.

  In the above embodiment, when the user selects and captures the DX size or the BX size as the selected pixel range, the camera system control unit 130 associates information related to the shift of the program diagram with the captured image data and records the recording unit. 141 may be recorded. For example, when photographing is performed in the state of the fifth column 165 in FIG. 6 described above, information of “FX conversion: focal length f = 75 mm, aperture value F = 5.6 equivalent” is associated with the photographed image data. Note that the information regarding the shift of the program diagram may be included in the shooting information recorded in the recording unit 141, or may be recorded in the recording unit 141 in a format different from the shooting information.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in said embodiment. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

10 single lens reflex camera, 11 optical axis, 12, 13 arrow, 20 interchangeable lens, 21 lens mount, 22 lens index, 23 focus lens, 24 zoom lens, 25 aperture, 30 camera body, 31 camera mount, 32 body index, 33 Lock pin, 34 Detachable button, 35 Release button, 36 Display, 37 Cross key, 38 Enter button, 39 Active frame, 40 Radio button, 41 Seesaw switch, 120 Lens system controller, 121 Lens mount contact, 122 Motor drive circuit , 123 Aperture drive circuit, 130 Camera system control unit, 131 Camera mount contact, 132 System memory, 133 Imaging device, 134 Shutter, 135 A / D converter, 136 Image processing unit, 137 Memory control unit, 1 8 Internal memory, 139 Display control unit, 140 External device IF, 141 Recording unit, 142 Power supply control unit, 143 Power supply, 144 Operation detection unit, 145 Photometric sensor, 146 Exposure control unit, 147 Focus control unit, 148 Zoom control unit, 151 1st pixel range, 152 2nd pixel range, 161 1st column, 162 2nd column, 163 3rd column, 164 4th column, 165 5th column, 166 6th column, 167 7th column

Claims (8)

An image sensor in which a plurality of pixels are two-dimensionally arranged;
A selection unit that selects, as a selection pixel range, a range of pixels corresponding to image data to be generated from the plurality of pixels;
An imaging apparatus comprising: a control unit that shifts a program diagram that defines an exposure value at the time of imaging based on the selected pixel range selected by the selection unit.   2. The control unit according to claim 1, wherein the control unit shifts the program diagram defined in accordance with a reference pixel range in the plurality of pixels based on a diagonal length ratio between the reference pixel range and the selected pixel range. Imaging device.   When the control unit converts to the same angle of view, a difference between the depth of field when shooting in the reference pixel range and the depth of field when shooting in the selected pixel range is determined in advance. The imaging apparatus according to claim 2, wherein the aperture value is determined so as to be within an allowable range.   4. The imaging apparatus according to claim 1, wherein the control unit shifts at least one of a shutter speed and an ISO sensitivity in accordance with a shift of an aperture value in the program diagram.   The imaging device according to claim 1, wherein the control unit determines whether to shift the program diagram based on a set shooting mode.   The imaging device according to claim 1, wherein the selection unit selects the selected pixel range based on a zoom instruction from a user.   The imaging apparatus according to claim 1, further comprising: an information adding unit that associates information related to the shift of the program diagram with the image data to be generated. A control program for an imaging apparatus including an imaging element in which a plurality of pixels are two-dimensionally arranged,
A selection step of selecting a range of pixels corresponding to the image data to be generated from the plurality of pixels as a selection pixel range;
A control program for an imaging apparatus that causes a computer to execute a control step for shifting a program diagram that defines an exposure value during imaging based on the selected pixel range selected in the selection step.

Images