JP2005277629A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a camera that can use the entire effective pixel of an image pickup device in photography, obtains the colorimetry information of a field without providing a photometric device prepared for colorimetry, and can precisely adjust white balance. <P>SOLUTION: The camera comprises the image pickup device having an imaging surface for photometrically converting an object image, an image pickup optical system for leading object light to the image pickup device, and an ambient light introduction means for leading ambient light to the inside in an optical path except the image pickup optical system. In the camera, the ambient light introduction means leads the ambient light onto an image pickup area to which an object image is led by the image pickup optical system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a camera, and more particularly to a camera that photoelectrically converts a subject image with an image sensor and stores image digital data after a predetermined process in a storage means.

  2. Description of the Related Art Conventionally, in a digital camera or video camera that captures and stores a subject image with an image sensor via an imaging optical system, white balance adjustment is generally performed on the obtained image data.

  This white balance adjustment is roughly divided into the following two methods. (1) A method of performing white balance processing on image data based on a predetermined algorithm without taking a colorimetric sensor, based on a predetermined algorithm, (2) having a colorimetric sensor, There is a method of measuring the color temperature around the object scene and applying white balance processing to the photographed subject image data based on the measured color temperature.

As the latter method, the imaging surface for imaging the subject on the imaging device is divided into an imaging area for photoelectrically converting the subject image and an area for receiving milky white light, and the area for receiving milky white light is derived from external light. A camera that guides milky white light is disclosed (for example, see Patent Document 1).
JP-A-6-153208

  Among the above white balance adjustments, the former method performs correction based on experience values and predicted values, and may make incorrect adjustments depending on subject conditions.

  On the other hand, the latter method is a preferable method because colorimetric information (color temperature information around the object scene) can be obtained for each photographing. However, since a photometric element for colorimetry is required, there are problems such as an increase in cost and space. Further, the camera described in Patent Document 1 does not require a photometric element for colorimetry, but uses an effective pixel portion formed on the imaging element by dividing it into a photographing area and an area that receives milky white light. Therefore, the captured image cannot use all the effective pixels of the image sensor, and there is a problem that the number of pixels of the image sensor cannot be fully utilized.

  In view of the above problems, the present invention can use all the effective pixels of the image sensor at the time of shooting, and obtain colorimetric information on the object field without providing a photometric element prepared for colorimetry. An object of the present invention is to obtain a camera capable of performing white balance adjustment.

  The above problem is solved by the following configuration.

  1) A camera having an imaging device having an imaging surface for photoelectrically converting a subject image, an imaging optical system that guides subject light to the imaging device, and an external light introducing unit that guides external light to the inside through an optical path other than the imaging optical system The camera is characterized in that the external light introducing means is configured to guide external light onto an imaging region where a subject image is guided by the imaging optical system.

  2) The camera according to 1), wherein white balance processing is performed on subject image data obtained from the image sensor based on an output of the image sensor obtained from the external light guided by the external light introducing means.

  3) The camera according to 1) or 2), wherein the external light introduction means guides external light while the imaging optical system is shifting from a retracted state to a state where photographing is possible.

  4) When the external light introducing means guides external light to the image sensor, the optical path of the image pickup optical system is shielded, and when the image pickup optical system guides subject light to the image sensor, The camera according to any one of 1) to 3), configured to prevent external light from external light introducing means from reaching the image sensor.

  According to the configuration of 1) above, the entire effective pixels of the image sensor can be used at the time of photographing, and the colorimetric information of the light source in the object field can be obtained without providing a photometric element prepared for colorimetry. Thus, it is possible to obtain a camera that can perform accurate white balance adjustment.

  According to the configuration of 2), a camera that performs accurate white balance adjustment can be obtained.

  According to the configuration of 3), it is possible to perform a light and comfortable feeling-free photographing without requiring time for performing a colorimetric operation during the photographing sequence.

  According to the configuration 4), accurate colorimetry can be performed.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is an external view of a digital camera according to the present invention. 1A is a perspective view of the front side of the camera, and FIG. 1B is a perspective view of the back side of the camera.

  In FIG. 1A, 81 is an imaging optical system such as a zoom lens, 82 is a finder window, 83 is a release button, 84 is a flash light emitting unit, 86 is a light control sensor window, 87 is a strap attaching unit, 88 Is an external input / output terminal (for example, a USB terminal). Reference numeral 89 denotes a lens cover. A main switch is turned on and off by operating the lens cover 89. When the main switch is turned off, the imaging optical system 81 is retracted. A milky white plate 103 is attached to the upper surface of the camera. From the milky white plate 103, external light is taken into the camera by external light introducing means described later.

  When the release button 83 is pushed in one step (hereinafter referred to as switch S1), the camera is prepared for shooting, that is, a focusing operation and photometric operation are performed. When the release button 83 is depressed in two steps (hereinafter referred to as switch S2 is turned on), shooting is performed. An exposure operation is performed.

  In FIG. 1B, 91 is a viewfinder eyepiece, and 92 is a red and green display lamp, which displays AF and AE information to the photographer by lighting or flashing when the switch S1 is turned on. is there. A zoom button 93 is a button for zooming up and down. Reference numeral 95 denotes a menu / set button, reference numeral 96 denotes a selection button, which is a four-way switch, and reference numeral 100 denotes an image display unit that displays an image, other character information, and the like. The menu / set button 95 has a function of displaying various menus on the image display unit 100, selecting with the selection button 96, and confirming with the menu / set button 95. Reference numeral 97 denotes a reproduction button, which is a button for reproducing a photographed image. A display button 98 is a button for selecting display or deletion of an image displayed on the image display unit 100 and other character information. An erasure button 99 is a button for erasing the recorded image. 101 is a tripod hole, and 102 is a battery / card cover. Inside the battery / card cover 102, a battery for supplying power to the camera and a card-type recording memory for recording captured images can be inserted and removed.

  FIG. 2 is a schematic block diagram showing the internal configuration of the digital camera shown in FIG. The internal configuration will be described with reference to FIG. In the present invention, a CCD, a CMOS, or the like can be applied as an image pickup device. In the following drawings, a CCD image sensor is used as the image pickup device.

  In the figure, reference numeral 40 denotes a CPU for controlling each circuit. The imaging optical system 81 includes a lens unit 1, an aperture shutter unit 2, an optical filter 3 in which an infrared light cut filter and an optical low-pass filter are stacked, a first motor 4, a second motor 5, and an aperture shutter actuator.

  In more detail, the lens unit 1 is configured as a lens system having a plurality of lenses, and the positions of the plurality of lenses on the optical axis are moved by driving the first motor 4 to perform collapsing and zooming. It is supposed to be. Among these lenses, a lens used for focusing is driven by the second motor 5 to perform focus adjustment. Further, the aperture shutter unit is opened and closed by the aperture shutter actuator 6 to adjust the exposure amount. The first motor 4, the second motor 5, and the aperture shutter actuator 6 are respectively connected via a first motor drive circuit 7, a second motor drive circuit 8, and an aperture shutter drive circuit 9 controlled by control signals from the CPU 40. Driven.

  The timing generator 10 generates a drive control signal for the CCD 12 based on a clock sent from the timing control circuit 11. For example, a timing signal for starting and ending charge accumulation in the CCD 12 and a readout control signal for the charge accumulation amount of each pixel. A clock signal such as (horizontal synchronization signal, vertical synchronization signal, transfer signal) is generated and output to the CCD 12. The imaging circuit 13 photoelectrically converts subject light by the CCD 12 and, for example, in the case of a CCD using a primary color filter, it outputs image analog signals of each color component of R (red), G (green), and B (blue). Output to the processing unit 14.

  Further, the CCD 12 has an external light introducing means 85 for guiding external light from the milky white plate 103 (see FIG. 1) to the inside through an optical path other than the imaging optical system 81. The external light introducing means 85 includes external light. Through the optical filter 3 so that the subject image of the CCD 12 is guided to an imaging region for photoelectric conversion. That is, the CCD 12 has both a function of photoelectrically converting a subject image by the imaging optical system 81 and a function of photoelectrically converting a projected image of the milky white plate 103 illuminated by the external light by the external light introducing unit 85.

  The signal processing unit 14 performs signal processing on the analog image signal output from the imaging circuit 13. In each of the above two functions, the signal processing unit 14 performs noise reduction and gain adjustment of the analog image signal by correlated double sampling (CDS) and auto gain control (AGC), and outputs it to the image processing unit 15. To do.

  The image processing unit 15 performs A / D conversion on the input image analog signal based on the A / D conversion clock from the timing control circuit 11 and converts it into a digital signal (hereinafter referred to as pixel data). Next, after correcting the black level of the pixel data, the white balance is adjusted.

  In the white balance adjustment, the CPU 40 evaluates the pixel data obtained by photoelectrically converting the projection image of the milky white plate 103 illuminated by the external light by the external light introducing means 85 described above, and sets each color data of the white balance processing. A correction amount is determined, and white balance processing is performed on subject image data obtained by photoelectrically converting a subject image by the imaging optical system 81 based on the correction amount.

  Thereafter, γ correction is performed, and pixel data is output to the image memory 16. The image memory 16 is a memory that stores pixel data output from the image processing unit 15.

  The VRAM 17 is a buffer memory for an image displayed on the image display unit 18, and has a storage capacity that is at least equal to the integrated value of the number of pixels of the image display unit 18 and the number of bits necessary for display. For the image display unit 18, for example, a display device such as an LCD or an organic EL is used. A D / A conversion unit that D / A converts pixel data is provided between the VRAM 17 and the image display unit 18 according to the display device used.

  Thereby, at the time of framing at the time of shooting, the pixel data imaged at a predetermined time interval is stored in the image memory 16, transferred to the VRAM 17 after predetermined signal processing by the CPU 40, and displayed on the image display unit 18. A subject image can be confirmed and used as a viewfinder (hereinafter referred to as preview image display).

  The captured image recorded in the removable recording memory 20 is transferred to the CPU 40 via the interface 19 and is transferred to the VRAM 17 after predetermined signal processing by the CPU 40 and displayed on the image display unit 18. , Playback is possible.

  The interface 19 exchanges signals with the detachable recording memory 20, and more specifically, writes image data to the recording memory 20 and reads recorded image data.

  The interface 32 exchanges signals with an external personal computer or printer. The interface 32 reads image data recorded in the recording memory 20 via an external input / output terminal (for example, USB terminal) 88, and external personal computer. The data is sent to a computer or a printer, or data is received from an external personal computer or a printer.

  The flash control circuit 21 is a circuit that controls the light emission of the flash light emitting unit 22. The flash control circuit 21 is controlled by the CPU 40 to control the presence / absence of flash light emission, the light emission timing, the charging of the light emission capacitor, and the like, and the light emission input from the light control circuit 24 connected to the light control sensor 23. The light emission is stopped based on the stop signal.

  The clock circuit 25 manages the date and time when the image was taken. The clock circuit 25 may operate by receiving power supply from a power supply circuit 27 that supplies power to each unit, but it is desirable to operate with a separate power source (not shown). .

  The power supply circuit 27 supplies power to the CPU 40 and each unit. The power supply circuit 27 is supplied with power from the A / C adapter 29 via the battery 26 or the DC input terminal 28.

  The operation SW 30 is a switch group that is turned ON / OFF by various operation buttons such as the release button 83, the zoom button 93, the menu / set button 95, etc. shown in FIG. The ON / OF signal of the operation SW 30 is sent to the CPU 40, and the CPU 40 controls the operation of each unit according to the operation SW that is turned on.

  The EEPROM 31 is a non-volatile memory, and is used for storing different characteristic values for each camera. The individually different characteristic values are, for example, information on the infinite position of the focusing lens at each focal length of the zoom imaging optical system 81, and are written in the manufacturing process. The CPU 40 reads out the characteristic values that are different for each camera from the EEPROM 31 as necessary, and uses them for controlling each part.

  The CPU 40 performs not only data exchange and timing control of each unit but also various other functions by software. For example, the aperture value and shutter speed exposure conditions at the time of shooting based on the pixel data obtained in the image memory 16 (AE function), the focusing lens is moved little by little, and the image data is obtained from the obtained pixel data. Generate and evaluate based on this image data, determine the optimum focusing lens position (AF function), and generate and compress image data from pixel data for recording in the recording memory 20. In order to display the recorded image on the image display unit 100, the image data recorded in the recording memory 20 is read and expanded, and the image processing function described below is provided.

  The above is the internal configuration of the digital camera according to the present invention.

  FIG. 3 shows external light introducing means for guiding the projection image of the milky white plate 103 illuminated by external light to the CCD 12 as the image sensor and for guiding the subject image by the imaging optical system 81 of the camera according to the present invention. 85 is a schematic diagram showing the state of 85 and the imaging optical system 81. FIG. FIG. 4A shows a state when the imaging optical system 81 is retracted, and FIG. 4B shows a state where the imaging optical system 81 is moving from the retracted position to the shootable position. ) Shows a state in which the image pickup optical system 81 is in the shooting enabled position. Moreover, the same figure (a)-(c) is the figure which the left figure looked at from the front, respectively, and the right figure has shown the cross section. In the following drawings, the same functional members are described with the same reference numerals in order to avoid duplication of explanation.

  As shown in FIG. 6A, when the image pickup optical system 81 of the camera is retracted, the internal aperture shutter unit 2 is kept closed, and the external light introducing means 85 is connected to the image pickup optical system 81 as shown. Separated and in a retracted state. When a main switch (not shown) is turned on from this retracted state, the imaging optical system 81 starts to be extended.

  As shown in FIG. 5B, in the middle of the taking-out of the imaging optical system 81, the external light introducing means 85 rotates around the rotation center 85t in the direction indicated by the illustrated arrow, and is milky white illuminated with external light. The projected image of the plate 103 is formed on the CCD 12 as an image sensor through the optical filter 3. As shown in the figure, the external light introducing means 85 is constituted by reflecting mirrors 85m, 85n, and 85p and a lens 85r that forms an image of the milky white plate 103 on the CCD 12. At this time, the image of the milky white plate 103 is projected onto at least a part of the imaging region where the subject image is photoelectrically converted, and the image of the milky white plate 103 at this time is photoelectrically converted from the obtained pixel data to white. A correction amount of each color data at the time of balance processing is determined.

  Further, the imaging optical system 81 continues to be extended and stops in a photographing enabled state (for example, a wide end state) as shown in FIG. At this time, the external light introducing means 85 is retracted from the CCD 12 as shown, the internal aperture shutter unit 2 is opened, and the CCD 12 receives the subject image by the imaging optical system 81 and can display a preview image. It becomes a state.

  FIG. 4 is a schematic view showing a change in state of shielding and introducing external light due to the rotation of the external light introducing means 85. The drawing shows the milky white plate 103 and the vicinity of the rotation center 85t of the external light introducing means 85 extracted. FIG. 4A shows a state when the external light shown in FIG. 3B is introduced into the CCD 12 by turning about the turning center 85t, and FIG. And the state when the external light introduction means 85 shown in FIG.3 (c) retreats away from the imaging optical system 81 is shown.

  As shown in FIG. 5A, the external light introducing means 85 has an opening 85k, and light from the opening 85k is introduced into the external light introducing means 85. For this reason, in the state shown in FIG. 3B, the opening 85k faces the milky white plate 103, and the external light introducing means 85 takes the image of the milky white plate 103 illuminated by the external light from the CCD 12. Will be able to be introduced to.

  On the other hand, as shown in FIG. 3B, in the state where the external light introducing means 85 is rotated about the rotation center 85t and retracted from the imaging optical system 81 (see FIGS. 3A and 3C). The opening 85k also rotates and enters a shielding state in which light from the milky white plate 103 cannot be introduced.

  Accordingly, when the external light introduction unit 85 guides external light to the image pickup device by the operation of the aperture shutter unit 2 described with reference to FIG. 3 and the operation of the external light introduction unit 85 described with reference to FIG. When the optical path of the system 81 is shielded and the imaging optical system 81 guides the subject light to the image sensor, it is possible to prevent the external light from the external light introducing means 85 from reaching the image sensor.

  FIG. 5 is a view showing an example of a mechanism for rotating the external light introducing means 85 to a retracted position and a position for introducing external light. FIG. 6A shows a state in which the image pickup optical system 81 is retracted, and FIG. 6B shows a state in the middle of moving from the retracted position to a shootable position (for example, a wide position). ) Shows a state in which the imaging optical system 81 is in a shootable position (for example, a wide position).

  In the figure, reference numeral 81c denotes a cam cylinder for collapsing and changing the magnification of the imaging optical system. Although not shown in the figure, a drive system composed of a first motor 4 (see FIG. 2) and a reduction gear train for rotating the cam cylinder 81c forward and backward, and detection for detecting the rotation angle of the cam cylinder 81c. The members are connected to each other. The detection member that detects the rotation angle may be arranged in the reduction gear train. Further, the cam cylinder 81c is formed with a missing gear portion 81g at a predetermined position different from the gear train to be rotated forward and backward.

  On the other hand, the engaging member 41 having the missing gear portion 41g is assembled to the outside light introducing means 85 so as to be rotatable independently of the rotation center 85t. The engaging member 41 is urged by the tension coil spring 42 so as to come into contact with a stopper 85 s formed in the external light introducing means 85. Further, the external light introducing means 85 is urged by the tension coil spring 43 in a direction to retract from the imaging optical system.

  In the retracted state of the imaging optical system 81 shown in FIG. 6A, the external light introducing means 85 is in a retracted state away from the imaging optical system by the tension coil spring 43, and is formed in the cam cylinder 81c. The missing gear portion 81g is in the position shown in the drawing.

  At this time, since the aperture shutter unit 2 is in a closed state (see FIG. 3A) on the image pickup area of the image pickup device, light comes on the image pickup area as shown on the right side of FIG. There is nothing.

  When the main switch of the camera is turned on, the first motor 4 (not shown) (see FIG. 2) is driven from this state, and the cam cylinder 81c is rotated in the clockwise direction. By this rotation, the missing gear portion 81g and the missing gear portion 41g of the engaging member 41 mesh with each other, whereby the engaging member 41 rotates counterclockwise against the tension coil spring 43 about the turning center 85t. To do.

  Thereafter, as shown in FIG. 3B, when the external light introducing means 85 is positioned on the image sensor 12 in the middle of moving from the retracted position to the shootable position (see FIG. 3B), temporarily. Then, the cam cylinder 81c is stopped and the image sensor is driven to project the above-mentioned projected image of the milky white plate illuminated by the external light on the image sensor through the optical filter. Thereby, colorimetric data for correcting each color data in the white balance processing is acquired. The stop position of the cam cylinder 81c is controlled when a detection member that detects a rotation angle detects a predetermined rotation angle.

  At this time, the aperture shutter unit 2 is in the closed state (see FIG. 3B), and as shown on the right side of FIG. 5B, the projected image of the milky white plate 103 by the external light introducing means 85 on the imaging region. Is formed.

  Thereafter, the cam cylinder 81c is further rotated clockwise. As a result, the meshing of the missing gear portion 81g and the missing gear portion 41g of the engaging member 41 is disengaged, and the external light introducing means 85 is retracted by the urging force of the tension coil spring 43 as shown in FIG. .

  Thereafter, the cam cylinder 81c stops at the wide position, and as described above, the aperture shutter unit is opened, and the image sensor receives the subject image from the imaging optical system 81 and is ready to display a preview image. . Subsequent rotation of the cam cylinder 81c in the clockwise direction is a variable power operation.

  At this time, the aperture shutter unit 2 is in an open state (see FIG. 3C), and as shown on the right side of FIG. 5C, a subject image is formed by the imaging optical system 81 on the imaging region.

  On the other hand, from the photographing enabled state to the retracted state, the cam cylinder 81c is rotated counterclockwise. When the cam cylinder 81c is rotated in the counterclockwise direction, the missing gear portion 41g of the engaging member 41 operates independently of the tension coil spring 42 against the rotation of the missing gear portion 81g. It is swung around in the turning direction and does not mesh.

  FIG. 6 is a flowchart showing the operation of the camera according to the present invention. Since the present invention relates to shooting, the description will be made assuming that the camera is set in the shooting mode in advance. A description will be given according to the flow shown in FIG.

  In the figure, when the main switch is turned on, the feeding optical operation is started with the imaging optical system at the retracted position directed to the shootable position (step S201).

  Next, it stops at a predetermined position that is a position in the middle of feeding (step S202). This state is the state shown in FIG. In this state, the process proceeds to the next step, operates the image sensor and related circuits, determines the accumulation time according to the amount of light, and then the pixel obtained by photoelectrically converting the projected image of the milky white plate by the external light introducing means The data is captured and evaluated, and the correction amount of each color data at the time of white balance processing is determined and stored in the CPU (step S203).

  After this operation is completed, the feeding operation is resumed and stopped at the photographing position of the imaging optical system (step S204). Thus, the state shown in FIGS. 3C and 5C is obtained, and a preview image of the subject image is displayed by the imaging optical system (step S205).

  Next, it is determined whether the main switch is ON (step S206). If the main switch is ON (step S206; Yes), it is determined again whether S1 is ON (step S207). If S1 is OFF (step S207; No), the process returns to S206, and step S206. The loop of step S207 is repeated. That is, as long as the main switch is turned on, it waits for S1 to be turned on.

  When S1 is turned on in step S207 (step S207; Yes), the AE / AF function operation is performed (step S208). The AE / AF function operation refers to a focusing operation and a photometry operation among the shooting preparation operations of the camera. When S1 is turned off in step S207 (step S207; No), the process returns to step S206 and the above-described operation is repeated.

  After the AE / AF function operation is finished, it is determined again whether S1 is ON (step S209). If it is ON (step S209; Yes), it is determined whether S2 is ON (step S210). In the case (step S210; No), the process returns to step S209. In other words, as long as S1 is turned on, it waits for S2 to be turned on.

  When S2 is turned on (step S210; Yes), a photographing operation is performed (step S211), the subject image is photoelectrically converted by the image sensor and the above-described predetermined image processing is performed (step S212). This image processing includes, in addition to various known processes, white balance processing based on the correction amount of each color data stored in the CPU in step S203.

  Thereafter, the subject image data subjected to the above processing is recorded in a recording memory. Thus, the shooting and recording of one sheet is completed, the process returns to step S206, and the above operation is repeated if the main switch is turned on (step S206; Yes).

  On the other hand, when the main switch is turned off in step S206 (step S206; No), the image pickup optical system is retracted (step S214).

  In this way, every time the main switch of the camera is turned on, it becomes possible to obtain colorimetric data of outside light in conjunction with the operation of extending the imaging optical system to the shootable position.

  Further, although the above-described white balance processing method is not described in detail, a known method described in, for example, JP-A-6-153208, JP-A-6-165189, JP-A-2003-169340, or the like is applied. can do.

  As described above, the external light introducing means guides the external light for measuring (colorimetric) the external light color temperature onto the imaging region for photoelectrically converting the subject image, so that the imaging element can be The entire effective pixel portion can be used, and a camera capable of obtaining the colorimetric information of the object scene and accurately adjusting the white balance without providing a photometric element prepared for colorimetry is obtained. It becomes possible.

  In addition, an external light introducing means is arranged at a position that does not interfere with the collapse of the imaging optical system, and a simple shutter is arranged between the milky white plate and the external light introducing means so that the imaging optical system is taken out or just before photographing. Even if the aperture shutter unit in the optical system is closed and the simple shutter is opened, the color measurement can be performed without departing from the present invention.

1 is an external view of a digital camera according to the present invention. It is a schematic block diagram which shows the internal structure of the digital camera shown in FIG. The state of the external light introducing means and the imaging optical system when the projection image of the milky white plate illuminated by the external light is guided to the CCD as the imaging device and the subject image by the imaging optical system of the camera according to the present invention It is a schematic diagram which shows. It is a schematic diagram which shows the state change of the shielding and introduction | transduction of external light by rotation of external light introduction means. It is the figure which showed an example of the mechanism which rotates an external light introduction means to the retracting position and the position which introduces external light. 3 is a flowchart showing the operation of the camera according to the present invention.

Explanation of symbols

2 Aperture Shutter Unit 3 Optical Filter 12 Imaging Device 81 Imaging Optical System 85 External Light Introducing Means 103 Milky White Plate

Claims (4)

In a camera having an imaging element having an imaging surface for photoelectrically converting a subject image, an imaging optical system that guides subject light to the imaging element, and an external light introduction unit that guides external light to the inside through an optical path other than the imaging optical system,
The camera according to claim 1, wherein the external light introducing means is configured to guide external light onto an imaging region where a subject image is guided by the imaging optical system. The camera according to claim 1, wherein white balance processing is performed on subject image data obtained from the image sensor based on an output of the image sensor obtained from external light guided by the external light introduction unit. . 3. The camera according to claim 1, wherein the external light introduction unit guides external light while the imaging optical system shifts from a retracted state to a photographable state. 4. When the external light introducing means guides external light to the image sensor, the optical path of the image pickup optical system is shielded, and when the image pickup optical system guides subject light to the image sensor, the external light The camera according to any one of claims 1 to 3, wherein external light from the introducing means is configured not to reach the image sensor.

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