JP2013145987A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce mismatch between an image obtained while a half mirror is advanced onto a light path between a projection optical system and an imaging device and an image obtained while the half mirror is retracted from the light path.SOLUTION: An imaging apparatus 1 comprises: an imaging device 13 which captures a subject image formed by a photographic lens 12; a half mirror 14; switch means which switches between a first state in which the half mirror 14 is advanced onto the light path between the photographic lens 12 and the imaging device 13 and a second state in which the half mirror 14 is retracted from the light path; and control means which performs control to read a pixel signal from the imaging device 13 so that the effective pixel area of the imaging device 13 from which a pixel signal is read is deviated between the first state and the second state.

Description

  The present invention relates to an imaging apparatus.

  In the following Patent Document 1, an image sensor that captures a subject image formed by an image pickup optical system, a first position that advances on an optical path between the image pickup optical system and the image sensor, and a first position that retreats from the optical path are disclosed. An image pickup apparatus including a half mirror provided so as to be movable between two positions is disclosed.

JP 2010-49134 A

  In the imaging device disclosed in Patent Document 1, when the half mirror is at the first position, the imaging element captures a subject image as a live view image (through image), and the half mirror is at the second position. In some cases, the imaging device captures the subject image as the actual captured image.

  However, whether the light incident on the image sensor along the optical axis of the imaging optical system is refracted by the half mirror when the half mirror is at the first position and when the half mirror is at the second position. Therefore, the incident position of the incident light with respect to the image sensor is shifted by, for example, several pixels to several tens of pixels. Therefore, the difference between the image captured by the image sensor when the half mirror is at the first position and the image captured by the image sensor when the half mirror is at the second position is the amount corresponding to the deviation. Inconsistency will occur.

  The present invention has been made in view of such circumstances, and an image obtained when the half mirror has advanced on the optical path between the projection optical system and the imaging device, and the half mirror retracted from the optical path. An object of the present invention is to provide an imaging apparatus capable of reducing inconsistency with an image obtained when the image is obtained.

  The following aspects are presented as means for solving the problems. An image pickup apparatus according to a first aspect includes an image pickup element that picks up a subject image formed by a shooting optical system, a half mirror, and the half mirror advances on an optical path between the shooting optical system and the image pickup element. Switching means for switching between a first state to be performed and a second state in which the half mirror is retracted from the optical path, and an effective pixel region of the image sensor from which a pixel signal is read out are the first state and the second state. Control means for performing control to read out a pixel signal from the image sensor so as to deviate from the above state.

  In the imaging device according to a second aspect, in the first aspect, the size of an effective pixel region of the imaging element from which the pixel signal is read out in the first state is read out in the second state. The size of the effective pixel area of the image sensor is the same, and the control means reads the pixel signal in the second state of the effective pixel area of the image sensor in which the pixel signal is read in the first state. The optical axis of the imaging optical system at a position on the imaging element where a light beam traveling along the optical axis of the imaging optical system reaches the imaging element in the first state is shifted from the effective pixel region of the imaging element. The displacement direction is the same and the displacement amount is smaller than twice (0.5 times the displacement with respect to the position on the image sensor on which the light beam traveling along the image element reaches the image sensor in the second state. Above One is preferably 1.5 times or less, and more preferably 1 ×.) So as to performs control to read out a pixel signal from the imaging device.

  An image pickup apparatus according to a third aspect includes an image pickup element that picks up a subject image formed by a shooting optical system, a half mirror, and the half mirror advances on an optical path between the shooting optical system and the image pickup element. Switching means for switching between a first state to be performed and a second state in which the half mirror is retracted from the optical path, and an effective pixel region of the image sensor from which a pixel signal is read out are the first state and the second state. The control means for performing control to read out the pixel signal from the image sensor so as to be the same in the state of the image sensor, and the first of the image sensor out of the pixel signal read from the image sensor in the first state. The pixel signal read from the effective pixel region is extracted, and the pixel signal read from the image sensor in the second state is shifted from the first effective pixel region of the image sensor. Extraction means for extracting a pixel signal read from the second effective pixel region of the imaging device, those having a.

  In the imaging device according to a fourth aspect, in the third aspect, the size of the first effective pixel region is the same as the size of the second effective pixel region, and the extraction unit includes the first effective pixel region. The photographing of the position of the effective pixel region with respect to the second effective pixel region at a position on the image sensor where a light beam traveling along the optical axis of the photographing optical system reaches the image sensor in the first state. The deviation direction is the same and the deviation amount is less than twice the deviation from the position on the image sensor in which the light beam traveling along the optical axis of the optical system reaches the image sensor in the second state. The pixel signal is extracted so that it is (0.5 times or more and 1.5 times or less, more preferably 1 time).

  The imaging device according to a fifth aspect is the imaging device according to any one of the first to fourth aspects, wherein the light beam traveling along the optical axis of the photographing optical system reaches the imaging element in the first state. The amount of deviation between the upper position and the position on the image sensor where the light beam traveling along the optical axis of the imaging optical system reaches the image sensor in the second state is the pixel pitch of the image sensor. Is an integer multiple of.

  The imaging device according to a sixth aspect is the imaging apparatus according to any one of the first to fifth aspects, wherein the half mirror is a pellicle mirror.

  The imaging apparatus according to a seventh aspect is the imaging apparatus according to any one of the first to sixth aspects, wherein the optical viewfinder forms an optical image of a subject by the light reflected by the half mirror in the first state, and the imaging And an image display unit that displays a subject image sequentially captured by the element as a moving image.

  In the image pickup apparatus according to an eighth aspect, in the seventh aspect, in the first state, an operation mode in which a user observes the optical viewfinder and performs image pickup by the image pickup device is performed.

  In the imaging device according to a ninth aspect, in the seventh or eighth aspect, in the second state, an operation mode in which a user observes the image display unit and performs imaging by the imaging element is performed. Is.

  An imaging device according to a tenth aspect includes the operation unit according to any one of the first to ninth aspects, and the switching unit is configured to change the first state and the second state according to an operation state of the operation unit. The state is switched.

  According to the present invention, an image obtained when the half mirror has advanced on the optical path between the projection optical system and the image sensor, and an image obtained when the half mirror is retracted from the optical path. It is possible to provide an imaging apparatus capable of reducing inconsistencies between the two.

It is a schematic sectional drawing which shows typically each state of the electronic camera by the 1st Embodiment of this invention. It is a schematic sectional drawing which shows typically a mode that the light ray which injects along the optical axis of the imaging lens in FIG. 1 permeate | transmits the half mirror which is mirror-down. It is a schematic block diagram which shows the electronic camera shown in FIG. It is a circuit diagram which shows schematic structure of the image pick-up element in FIG. It is a schematic plan view which shows typically the effective pixel area | region of the image pick-up element in FIG. It is a schematic plan view which shows the operation lever which comprises a part of operation part in FIG. 3 is a schematic flowchart illustrating an example of an operation of the electronic camera illustrated in FIG. 1. It is a schematic flowchart which shows an example of operation | movement of the electronic camera by the 2nd Embodiment of this invention.

  Hereinafter, an imaging device according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view schematically showing each state of an electronic camera 1 as an imaging apparatus according to an embodiment of the present invention. FIG. 1A shows a state where the half mirror 14 is mirror-up (second state), and FIG. 1B shows a state where the half mirror 14 is mirror-down (first state). As shown in FIG. 1, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. Of the X axis directions, the direction of the arrow is called the + X direction or the + X side, and the opposite direction is called the -X direction or the -X side, and the same applies to the Y axis direction and the Z axis direction. The Z axis coincides with the direction of the optical axis O of the photographing lens 12 of the electronic camera 1, the X axis coincides with the left and right direction of the electronic camera 1, and the Y axis coincides with the up and down direction of the electronic camera 1. The X-axis direction coincides with the row direction (horizontal direction) of the image sensor 13, and the Y-axis direction coincides with the column direction (vertical direction) of the image sensor 13.

  Although the electronic camera 1 according to the present embodiment is configured as a so-called digital camera, the imaging device according to the present invention can be applied not only to a digital camera but also to other imaging devices.

  In the electronic camera 1 according to the present embodiment, a photographing lens 12 as a photographing optical system is mounted in front of the camera body 11. The photographing lens 12 may be exchangeable or non-exchangeable. On the back surface of the camera body 11, a display unit 19 configured by a back liquid crystal panel or the like is provided.

  An image sensor 13 is disposed on the optical axis O of the photographing lens 12. The image sensor 13 is fixed to the camera body 11 via a fixing member or the like. The half mirror 14 advances on the optical path between the photographing lens 12 and the image sensor 13 and separates the light from the photographing lens 12 into light that is transmitted in the + Z direction and light that is reflected in the + Y direction. The position (solid line position in FIG. 1B) and the light path between the photographing lens 12 and the image sensor 13 are withdrawn, and the light from the photographing lens 12 passes in the + Z direction as it is without being reflected or transmitted. It is provided so as to be movable to the second position to be moved (solid line position in FIG. 1A). In the following description, the state in which the half mirror 14 is positioned at the solid line position in FIG. 1A is a state in which the half mirror 14 is mirroring up (mirror up state, second state), and the half mirror 14 is in FIG. The state located at the solid line position in (b) may be referred to as a state where the half mirror 14 is mirror-down (mirror-down state, first state).

  When the half mirror 14 is mirrored up, the light from the photographic lens 12 travels in the + Z direction as it is without being reflected or transmitted by the half mirror 14 and reaches the image sensor 13. A subject image by the light is formed on the image sensor 13, and the subject image is captured by the image sensor 13. When the half mirror 14 is mirror-down, the light from the photographing lens 12 is separated into light that is transmitted through the half mirror 14 in the + Z direction and light that is reflected by the half mirror 14 in the + Y direction. A subject image by light transmitted through the half mirror 14 in the + Z direction is formed on the image sensor 13 by the photographing lens 12, and the subject image is captured by the image sensor 13.

  On the + Y side of the half mirror 14, a focusing screen 15 and a pentaprism 16 are arranged in this order. On the + Z side of the pentaprism 16, an eyepiece lens 17 and an eyepiece window 18 are sequentially arranged. The subject image formed by the light reflected in the + Y direction by the half mirror 14 that is mirror-down is once formed on the focusing screen 15 by the photographing lens 12, and the light once formed on the focusing screen 15 is a pentaprism. After being incident on 16 and reflected twice on the inner surface thereof, it is emitted from the pentaprism 16 in the + Z direction, passes through the eyepiece lens 17 and the eyepiece window 18, and looks into the eyepiece window 18 (not shown). To reach. The eyepiece 17 forms a subject image on the eyes of the user. As described above, the focusing screen 15, the pentaprism 16, the eyepiece lens 17, and the eyepiece window 18 constitute an optical viewfinder (OVF) that forms an optical image of the subject by the light reflected by the half mirror 14 in the mirror-down state. Yes.

  As the half mirror 14, for example, a pellicle mirror is used. However, the half mirror is not limited to this, and a half mirror configured using a glass plate or the like may be used. The pellicle mirror is configured, for example, by coating a thin transflective film such as polyethylene terephthalate (PET) so that desired transmittance and reflectance can be obtained. The transmittance and reflectance of the half mirror 14 are not limited to 50% and 50%, respectively, and may be other values.

  FIG. 2 is a schematic cross-sectional view schematically showing a state in which light rays incident along the optical axis O of the photographing lens 12 in FIG. 1 are transmitted through the half mirror 14 in a mirror-down state. In FIG. 2, the illustration of the light reflected by the half mirror 14 is omitted.

  Since the half mirror 14 can be regarded as a parallel plate, light rays that pass through the half mirror 14 out of light rays that are incident on the half mirror 14 that is mirrored down along the optical axis O at an incident angle φ are half mirrors 14. After being refracted at a refraction angle ψ when entering the lens, it is refracted again when exiting from the half mirror 14, and parallel to the optical axis O along the line O ′ shifted by Δy in the −Y direction from the optical axis O. Proceed in the + Z direction. The shift amount Δy is preferably an integer multiple of the pixel pitch of the image sensor 13, but is not necessarily limited thereto. In order to set the shift amount Δy to an integral multiple of the pixel pitch of the image sensor 13, for example, the refractive index n of the half mirror 14 is adjusted, or the angle of the half mirror 14 in the mirror down state (that is, the incident angle φ) is set. You can adjust it.

  Now, assuming that the thickness of the half mirror 14 is d, the shift amount Δy is expressed as Δy = d · sin (φ−ψ) / cosψ. The shift amount Δy depends on the pixel pitch, but corresponds to a shift of several pixels to several tens of pixels, for example. The refractive index n of the half mirror 14 is expressed as n = sinφ / sinψ.

  FIG. 3 is a schematic block diagram showing the electronic camera 1 according to the present embodiment. The photographing lens 12 is driven by the lens control unit 21 for focus and diaphragm. The image pickup device 13 is driven by a control signal output from the image pickup control unit 22 and outputs an image signal indicating a subject image. In the present embodiment, the signal output from the image sensor 13 is processed through the signal processing unit 23 and the A / D conversion unit 24 and then temporarily stored in the memory 25. The memory 25 is connected to the bus 26. The bus 26 includes a display unit 19, a lens control unit 21, an imaging control unit 22, a CPU 27, a focus calculation unit (detection processing unit) 28, a recording unit 29, an image processing unit 30, an image compression unit 31, and a mirror position switching unit 32. Etc. are also connected. The CPU 27 is connected to a release button and an operation unit 34 such as an operation lever 34a described later. A recording medium 29a is detachably attached to the recording unit 29. For example, the imaging control unit 22, the signal processing unit 23, and the A / D conversion unit 24 may be mounted on the same chip as the imaging element 13.

  FIG. 4 is a circuit diagram showing a schematic configuration of the image sensor 13 in FIG. The image sensor 13 has a plurality of pixels 40 arranged in a two-dimensional matrix and a peripheral circuit for outputting a signal from the pixels 40. In FIG. 4, an effective pixel region in which the pixels 40 are arranged in a matrix is indicated by reference numeral 51. In FIG. 4, 16 pixels of 4 rows horizontally and 4 rows vertically are shown. However, in the present embodiment, the number of pixels is much larger than that. However, in the present invention, the number of pixels is not particularly limited.

  The peripheral circuit includes a vertical scanning circuit 41, a horizontal scanning circuit 42, drive signal lines 43 and 44 connected thereto, a vertical signal line 45 for receiving a signal from the pixel 40, and a constant current source connected to the vertical signal line 45. 46, a correlated double sampling circuit (CDS circuit) 47, a horizontal signal line 48 for receiving a signal output from the CDS circuit 47, an output amplifier 49, and the like.

  The vertical scanning circuit 41 and the horizontal scanning circuit 42 output drive signals based on control signals from the imaging control unit 22 of the electronic camera 1. Each pixel 40 is driven by receiving a drive signal output from the vertical scanning circuit 41 from a predetermined drive signal line 43, and outputs a pixel signal to the vertical signal line 45. The signal output from the pixel 40 is subjected to predetermined noise removal by the CDS circuit 47. Then, a signal is output to the outside through the horizontal signal line 48 and the output amplifier 49 by the drive signal of the horizontal scanning circuit 42.

  The vertical scanning circuit 41 reads out a pixel signal from an upper area (A + B), which will be described later in the effective pixel area 51, according to a control signal output from the imaging control unit 22. The pixel signal can also be read from the side region (B + C).

  Although not shown in the drawing, each pixel 40 receives, for example, a photodiode as a photoelectric conversion unit that generates and accumulates charges according to incident light, as in a general CMOS image sensor, and receives the charges. A floating capacitor that converts the charge into a voltage; an amplifying transistor that outputs a signal corresponding to the potential of the floating capacitor; a transfer transistor that transfers charge from the photodiode to the floating capacitor; and a potential of the floating capacitor And a selection transistor for selecting the pixel 40. However, the specific configuration of each pixel 40 is not limited to such a configuration.

  FIG. 5 is a schematic plan view schematically showing the effective pixel region 51 of the image sensor 13 in FIG. FIG. 5 also shows the optical axis O and the line O ′ in FIG. The optical axis O and the line O ′ extend in a direction perpendicular to the paper surface in FIG.

  The effective pixel region 51 includes an upper region A having a vertical width equal to the shift amount Δy, a lower region C having a vertical width equal to the shift amount Δy, an upper region A, and a lower region C. And an intermediate region B between the two. The region composed of the upper region A and the intermediate region B is referred to as “upper region (A + B)”, and the region composed of the intermediate region B and the lower region C is referred to as “lower region (B + C)”. The size of the upper region (A + B) and the size of the lower region (B + C) are the same, and the upper region (A + B) and the lower region (B + C) are shifted by the shift amount Δy in the Y-axis direction.

  Referring to FIG. 3 again, the mirror position switching unit 32 is in a state where the half mirror 14 is positioned at the solid line position in FIG. 1A (mirror up state) and the half mirror 14 is in FIG. (B) The state (mirror down state) located at the solid line position is switched. The mirror position switching unit 32 can be configured using a known mirror moving mechanism or the like.

  Under the control of the CPU 27, the imaging control unit 22 shifts the effective pixel area of the imaging element 13 from which the pixel signal is read in the mirror-up state and the effective pixel area of the imaging element 13 from which the pixel signal is read in the mirror-down state. In addition, control is performed to read out pixel signals from the image sensor 13. In the present embodiment, the imaging control unit 22 shifts the effective pixel area of the image sensor 13 from which the pixel signal is read in the mirror-down state with respect to the effective pixel area of the image sensor 13 from which the pixel signal is read in the mirror-up state. The light of the photographic lens 12 at a position on the image sensor 13 where the light beam traveling along the optical axis O of the photographic lens 12 reaches the image sensor 13 in a mirror-down state (that is, the position of the line O ′ on the image sensor 13). The shift direction is the same as the shift with respect to the position on the image sensor 13 where the light beam traveling along the axis O reaches the image sensor 13 in the mirror-up state (that is, the position of the optical axis O on the image sensor 13). At the same time, the image pickup element 1 is such that the amount of deviation is smaller than twice (0.5 times or more and 1.5 times or less, more preferably 1 time). Performs control to read out pixel signals from.

  Specifically, in the present embodiment, the imaging control unit 22 reads the pixel signal in the lower region (B + C) in FIG. 5 of the imaging device 13 in the mirror-down state, and the imaging device 13 in the mirror-up state. The pixel signal is read out from the image sensor 13 so that the upper area (A + B) in FIG. As a result, the lower region (B + C), which is the effective pixel region of the image sensor 13 from which the pixel signal is read in the mirror-down state, and the upper region (B + C), which is the effective pixel region of the image sensor 13 from which the pixel signal is read in the mirror-up state. The deviation with respect to A + B) is the same −Y direction as the deviation direction of the position of the line O ′ on the image pickup device 13 with respect to the position of the optical axis O on the image pickup device 13, and the amount of deviation is one time. The pixel signal is read out from the image sensor 13 so as to satisfy Δy.

  FIG. 6 is a schematic plan view showing an operation lever 34 a constituting a part of the operation unit 34. The operation lever 34a indicates that the user selects to check the composition using the optical viewfinder (OVF), and the user can check the composition using the live view (LV). The LV position to be selected can be selected, and an operation signal indicating the selected state is supplied to the CPU 27 via the bus 26. The live view is an operation of displaying an image (through image) repeatedly captured by the image sensor 13 on the display unit 19 as a moving image in real time.

  The electronic camera 1 according to the present embodiment can perform imaging by the imaging element 13 in both the mirror up state and the mirror down state.

  FIG. 7 is a schematic flowchart showing an example of the operation of the electronic camera 1 according to the present embodiment. FIG. 7 shows the operation in the still image shooting mode.

  When the operation unit 34 instructs the start of the still image shooting mode, the CPU 27 confirms the selection state of the operation lever 34a (step S1), and then determines whether to mirror up the half mirror 14 (step S2). ). In the present embodiment, specifically, when the live view is selected by the operation lever 34a, the CPU 27 determines that the mirror is not raised (that is, the mirror is lowered), and the operation lever 34a uses the optical viewfinder. If is selected, it is determined that the mirror is up.

  If it is determined in step S2 that the mirror is not raised, the CPU 27 determines whether or not the half mirror 14 has been mirrored down (step S3). This determination can be made based on, for example, a command given to the mirror position switching unit 32 by the CPU 27.

  If it is determined in step S3 that the mirror has not been lowered, the CPU 27 causes the half mirror 14 to mirror down as indicated by the solid line in FIG. 1B via the mirror position switching unit 32 (step S4). The effective pixel area of the image sensor 13 that reads out the pixel signal is set to the lower area (B + C) in FIG. 5 (step S5), and then the process proceeds to step S10.

  On the other hand, if it is determined in step S3 that the mirror has been lowered, the process proceeds to step S10 without going through steps S4 and S5.

  If it is determined in step S2 that the mirror is to be raised (NO in step S2), the CPU 27 determines whether or not the half mirror 14 has been mirrored (step S6).

  If it is determined in step S6 that the mirror has not been raised, the CPU 27 causes the half mirror 14 to mirror up as shown by the solid line in FIG. 1A via the mirror position switching unit 32 (step S7). Next, the CPU 27 sets the effective pixel area of the image sensor 13 from which the pixel signal is read out to the upper area (A + B) in FIG. 5 (step S8).

  After step S8, the CPU 27 controls the imaging control unit 22 to cause the image sensor 13 to sequentially capture the subject images and display the images (through images) on the display unit 19 as moving images (step S9). The process proceeds to step S10. Note that the imaging and display in step S9 are performed by reading out a pixel signal from the upper area (A + B) of the image sensor 13 set in step S8 and displaying the image.

  On the other hand, if it is determined in step S6 that the mirror has been raised, the process proceeds to step S9 without going through steps S7 and S8.

  In step S10, the CPU 27 determines whether or not a release button (not shown) in the operation unit 34 is half-pressed, and waits until it is half-pressed if not half-pressed. However, although not shown in the drawing, the process returns to step S1 if it is not half-pressed even after a predetermined time-out period has elapsed.

  If the release button is pressed halfway before the time-out period elapses, the CPU 27 performs automatic focus adjustment, automatic exposure control, and the like, and sets shooting conditions used for shooting the main image (step S11).

  Subsequently, the CPU 27 determines whether or not the release button is fully pressed (step S12), and waits until the release button is fully pressed. However, although not shown in the drawing, if the button is not fully pressed even after a predetermined time-out period has elapsed, the process returns to step S1.

  If the release button is fully pressed before the time-out period elapses, the CPU 27 controls the imaging control unit 22 to cause the imaging device 13 to capture the main image (step S13). At this time, the CPU 27 controls the imaging control unit 22 to read out the pixel signal from the area of the imaging element 13 currently set at the latest in step S5 or step S8 as the area of the imaging element 13 from which the pixel signal is read out. A pixel signal read from the region is set as a main image. The main image read out from the image sensor 13 as an analog signal is amplified by the signal processing unit 23, converted to a digital signal by the A / D conversion unit 24, and further temporarily stored in the memory 25.

  Next, the CPU 27 causes the recording unit 29 to record the main image read in step S13 and stored in the memory 25 on the recording medium 29a (step S14).

  Although not shown in the drawing, after step S14, whether or not a mode end command (for example, a command to switch to another operation mode or a power-off command) is received from the operation unit 34 to end the still image shooting mode. If it is determined that the mode end command has not been received, the process returns to step S1. If it is determined that the mode end command has been received, the still image shooting mode is ended.

  As can be seen from the above description, in the present embodiment, steps S3 to S5 and S10 to S14 performed when YES is determined in step S2, the user observes the optical viewfinder, and imaging by the image sensor 13 is performed. This corresponds to an operation mode, and this operation mode is performed in a mirror-down state. Further, in the present embodiment, steps S6 to S9 and S10 to S14 performed when NO is determined in step S2 corresponds to an operation mode in which the user observes the display unit 19 and the imaging element 13 performs imaging. This operation mode is performed in the mirror up state.

  However, even if the optical finder is used to check the composition, it is not always necessary to capture the main image while the mirror is down, and the live view is displayed on the display unit 19 to check the composition. Even if the through image is used, it is not always necessary to capture the through image or the main image while the mirror is raised. For example, when checking the composition with the optical viewfinder, the mirror is in the mirror-down state, and when the main image is subsequently taken, the subject is kept in the mirror-down state when the subject brightness is high. If the brightness of the screen is low, the mirror may be automatically raised. In addition, for example, when the brightness of the subject is low, the mirror is automatically raised when the composition is confirmed in the live view and when the main image is subsequently taken, while the brightness of the subject is If it is high, the mirror may be automatically brought into the mirror-down state when the composition is confirmed in the live view and also when the main image is subsequently taken. Further, for example, a selection operation member that directly selects the mirror up state and the mirror down state is provided separately from the operation lever 34a, and only whether or not to perform imaging / display by live view depending on the selection state of the operation lever 34a. And the mirror up state and the mirror down state may be switched only depending on the operation state of the selection operation member. In any case, in the present invention, the effective pixel area of the image sensor 13 that reads out a pixel signal may be changed between the mirror-up state and the mirror-down state.

  In the present embodiment, as can be seen from the above description, the pixel signal in the lower region (B + C) in FIG. 5 of the image sensor 13 in FIG. 5 is read in the mirror-down state, and FIG. The middle upper area (A + B) is read out. The lower region (B + C) is shifted from the upper region (A + B) by the shift amount Δy in the −Y direction. Therefore, according to the present embodiment, the image captured by the image sensor 13 in the mirror-up state matches the image captured by the image sensor 13 in the mirror-down state without any deviation. Inconsistency between the two images does not become a problem.

  On the other hand, in both the mirror-up state and the mirror-down state, if the effective area of the image sensor 13 that reads out pixel signals is the upper area (A + B), the image captured by the image sensor 13 in the mirror-up state And the image picked up by the image pickup device 13 in the mirror-down state are shifted by the shift amount Δy and do not coincide with each other, resulting in inconvenience. As described above, according to the present embodiment, such inconvenience does not occur.

[Second Embodiment]
FIG. 8 is a schematic flowchart showing an example of the operation of the electronic camera according to the second embodiment of the present invention, and corresponds to FIG. In FIG. 8, steps that are the same as or correspond to steps in FIG. 7 are given the same reference numerals, and redundant descriptions thereof are omitted. The electronic camera according to the present embodiment is different from the electronic camera 1 according to the first embodiment in the following points.

  In the first embodiment, as described above, the pixel signal in the lower region (B + C) of FIG. 5 of the image sensor 13 in FIG. 5 is read in the mirror-down state, and FIG. The middle upper area (A + B) is read out. On the other hand, in the present embodiment, the entire effective pixel region 51 (that is, the region (A + B + C)) of the image sensor 13 is read in both the mirror-down state and the mirror-up state, and the region is in the mirror-up state. From the pixel signal read out from (A + B + C), the pixel signal read out from the upper area (A + B) is extracted to obtain an image finally obtained, and read out from the area (A + B + C) in the mirror-down state. From the obtained pixel signal, the pixel signal read from the lower region (B + C) is extracted to obtain an image finally obtained.

  Specifically, in this embodiment, steps S21 and S22 are performed instead of steps S5 and S8 described above. In step S <b> 21, the CPU 27 sets a signal of a region to be extracted from pixel signals read from the region (A + B + C) of the image sensor 13 as a signal of the lower region (B + C). In step S <b> 22, the CPU 27 sets the signal of the area to be extracted from the pixel signals read from the area (A + B + C) of the image sensor 13 to the signal of the upper area (A + B). In this embodiment, in step S13, the CPU 27 controls the imaging control unit 22 to always read out the pixel signal from the area (A + B + C) of the imaging element 13 and convert it into a digital signal, and then to the memory 25. Is stored once. Further, in the present embodiment, after step S13, the CPU 27 controls the image processing unit 30, and from the pixel signal read from the area (A + B + C) of the image sensor 13 and stored in the memory 25, the step S21 or The pixel signal read from the area of the image sensor 13 that is currently set to the latest in S22 is extracted (step S23). Further, in the present embodiment, after step S23, in step S14, the CPU 27 causes the recording unit 29 to record the pixel signal extracted in step S23 as a finally obtained image on the recording medium 29a.

  Also in the present embodiment, as in the first embodiment, an image finally obtained based on an image captured by the image sensor 13 in the mirror-up state and an image captured by the image sensor 13 in the mirror-down state The images finally obtained on the basis of the obtained images are matched without any deviation, so that the mismatch between the images does not become a problem.

  In the first embodiment, although it is necessary to change the region of the image sensor 13 from which the pixel signal is read out between the mirror-up state and the mirror-down state, it is not necessary to perform extraction processing after reading out the pixel signal. On the other hand, in the present embodiment, although it is necessary to perform extraction processing after reading out the pixel signal, it is not necessary to change the region of the image sensor 13 from which the pixel signal is read out between the mirror-up state and the mirror-down state.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

  For example, an electronic viewfinder (EVF) may be added to the electronic camera according to each of the above embodiments. In this case, for example, when checking the composition using the electronic view finder is selected by the operation unit 34, the same as when selecting checking the composition using the live view described above is selected. Instead of displaying the through image on the display unit 19 in the mirror-up state, the through image may be displayed on the display unit constituting the electronic viewfinder.

DESCRIPTION OF SYMBOLS 1 Electronic camera 12 Shooting lens 13 Image sensor 14 Half mirror 22 Imaging control part 32 Mirror position switching part

Claims (10)

An image sensor for imaging a subject image formed by the imaging optical system;
Half mirror,
Switching means for switching between a first state in which the half mirror advances on the optical path between the imaging optical system and the imaging element and a second state in which the half mirror is retracted from the optical path;
Control means for performing control to read out the pixel signal from the image sensor so that an effective pixel area of the image sensor from which the pixel signal is read out is shifted between the first state and the second state;
An imaging apparatus comprising: The size of the effective pixel region of the image sensor from which the pixel signal is read out in the first state is the same as the size of the effective pixel region of the image sensor from which the pixel signal is read out in the second state;
The control means is configured such that a deviation of an effective pixel area of the image sensor from which the pixel signal is read in the first state with respect to an effective pixel area of the image sensor from which the pixel signal is read in the second state is A light beam traveling along the optical axis of the imaging optical system at a position on the image sensor that reaches the image sensor in the first state is a light beam traveling along the optical axis of the imaging optical system in the second state. Control is performed to read out pixel signals from the image sensor so that the displacement direction is the same and the amount of displacement is less than twice the displacement relative to the position on the image sensor that reaches the image sensor. The imaging apparatus according to claim 1. An image sensor for imaging a subject image formed by the imaging optical system;
Half mirror,
Switching means for switching between a first state in which the half mirror advances on the optical path between the imaging optical system and the imaging element and a second state in which the half mirror is retracted from the optical path;
Control means for performing control to read out the pixel signal from the image sensor so that the effective pixel area of the image sensor from which the pixel signal is read out is the same in the first state and the second state;
The pixel signal read from the first effective pixel region of the image sensor is extracted from the pixel signals read from the image sensor in the first state, and the image sensor in the second state. Extracting means for extracting a pixel signal read from the second effective pixel region of the image sensor that is shifted from the first effective pixel region of the image sensor from among the pixel signals read from
An imaging apparatus comprising: The size of the first effective pixel region is the same as the size of the second effective pixel region;
The extraction means is configured such that a deviation of the first effective pixel region from the second effective pixel region is such that a light beam traveling along an optical axis of the photographing optical system reaches the image pickup device in the first state. The shift direction is the same as the shift of the position on the image sensor with respect to the position on the image sensor where the light beam traveling along the optical axis of the imaging optical system reaches the image sensor in the second state. 4. The image pickup apparatus according to claim 3, wherein the pixel signal is extracted so that the shift amount is smaller than twice.   The position on the image sensor where the light beam traveling along the optical axis of the photographic optical system reaches the image sensor in the first state, and the light beam traveling along the optical axis of the photographic optical system is the second. 5. The imaging according to claim 1, wherein an amount of deviation from a position on the image sensor that reaches the image sensor in the state is an integer multiple of a pixel pitch of the image sensor. apparatus.   The imaging apparatus according to claim 1, wherein the half mirror is a pellicle mirror.   An optical viewfinder that forms an optical image of a subject by light reflected by the half mirror in the first state, and an image display unit that displays subject images sequentially captured by the imaging device as a moving image. The imaging apparatus according to claim 1, wherein:   The imaging apparatus according to claim 7, wherein an operation mode in which a user observes the optical viewfinder and performs imaging by the imaging element is performed in the first state.   The imaging apparatus according to claim 7 or 8, wherein an operation mode in which a user observes the image display unit and performs imaging by the imaging element is performed in the second state. It has an operation part,
The imaging apparatus according to claim 1, wherein the switching unit switches between the first state and the second state according to an operation state of the operation unit.

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