JP2005020199A - Digital single-lens reflex camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital single-lens reflex camera friendly to a photographer by preventing the camera operations from being stopped due to the loss of power supply residual amount in the midst of consecutive shots. <P>SOLUTION: The digital single-lens reflex camera is characterized in including: an imaging means 27; a finder optical system 30; a movable mirror 24; a voltage discrimination means 58 for measuring the voltage of a power supply battery 57 to discriminate the voltage; a display means 8 for displaying the object image imaged by the imaging means 27; and a selection means in the case of consecutive shots for selecting a first mode wherein the imaging operation by the imaging means 27 and an image display operation by the display means 8 are repeated while facing up the movable mirror 24 in response to a result of the discrimination by the voltage discrimination means 58 or a second mode wherein the imaging operation for moving the movable mirror to first and second positions is executed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital single-lens reflex camera, and more particularly to a digital single-lens reflex camera that observes a subject using a finder optical system and picks up a subject image using a solid-state image sensor.
[0002]
[Prior art]
As is well known, a finder device for a single-lens reflex camera using a silver salt film is generally an optical finder that uses an optical member such as a pentaprism or a porro prism to observe an optical subject image. A finder device for a digital single-lens reflex camera is a so-called electronic viewfinder in which a display element is further arranged on an optical finder device, an output of an image sensor is displayed on the display element, and an electronic subject image is observed from the finder. It is also possible to configure as. There are also known finder apparatuses that can arbitrarily switch between the state of the electronic viewfinder and the state of the optical viewfinder.
[0003]
By the way, a digital single-lens reflex camera sharing an optical viewfinder and an electronic viewfinder has an advantage that the continuous shooting (continuous shooting) operation can be speeded up.
[0004]
In view of such advantages, the present applicant keeps the movable mirror of the optical finder retracted from the imaging optical path with the start of the continuous shooting operation, and at that time, the captured electronic image is an optical subject by the optical finder. Japanese Patent Application Laid-Open No. 2004-228867 proposes a finder apparatus that shares an optical viewfinder and an electronic viewfinder, in which an electronic subject image is observed with an electronic viewfinder instead of an image.
[0005]
If the finder device is configured in this way, it is not necessary to move the movable mirror up and down during continuous shooting, so that noise and vibration due to the movable mirror operating at high speed can be suppressed, and the continuous shooting speed can be increased. There is a great advantage.
[0006]
[Patent Document 1]
Japanese Patent Application No. 2002-6502
[Problems to be solved by the invention]
By the way, as the display means used in the electronic viewfinder, an LCD configured to include a display element for displaying a captured electronic image and a backlight for illuminating the display surface of the display element from the back is used. Yes.
[0008]
Therefore, in order for the photographer to observe the electronic subject image with the electronic viewfinder, the display element is illuminated from behind by the backlight, which causes a problem that the power consumption increases. For this reason, if continuous shooting is performed when the remaining power of the camera is low or the power supply voltage is low due to low temperature, the remaining power will run out during the continuous shooting, and the camera operation itself will stop. There is a risk of it.
[0009]
In such a case, the photographer observing the captured electronic subject image with the electronic viewfinder is very uneasy because the camera stops suddenly and the viewfinder becomes dark. Further, this is not taken into consideration in the above-mentioned Patent Document 1.
[0010]
An object of the present invention is to provide a digital single-lens reflex camera that is easy to use for photographers and that prevents such problems from occurring.
[0011]
[Means for solving the problems and actions]
In order to achieve the above object, a digital single-lens reflex camera according to the present invention is a digital single-lens reflex camera having an image pickup means, which is in a finder optical system and an image pickup optical path of the image pickup means, A movable mirror that is at a first position for guiding a light beam to the finder optical system and moves to a second position retracted from the imaging optical path during an imaging operation by the imaging means; and a power supply voltage of the camera; A voltage determination means for determining the power supply voltage; and a display element for displaying a subject image picked up by the image pickup means, and the image displayed on the display element is a part of the observation optical path of the finder optical system. In accordance with the display means that can be shared and observed and the determination result of the voltage determination means, the image pickup operation by the image pickup means and the movable mirror are moved to the second position, and The first mode in which the image display operation by the display means is repeated, and the imaging operation in which the movable mirror is moved to the first position and the second position without executing the image display operation. Selecting means for selecting one of the two modes.
[0012]
The selection means can select the first mode when the voltage determination means determines that the power supply voltage is equal to or higher than a predetermined value, and the second means when the voltage determination means determines that the power supply voltage is lower than the predetermined value. The predetermined value is a value of a power supply voltage at which a predetermined number of imaging operations by the imaging unit and an image display operation by the display unit can be continuously executed. In addition, the voltage determination unit performs power supply voltage measurement and an operation of determining whether or not the power supply voltage is equal to or higher than the predetermined value prior to the imaging operation by the imaging unit. And
[0013]
Further, the display device further comprises warning means for notifying the photographer that the second mode has been selected by the selection means, and the warning means is provided in the viewfinder eyepiece. It is characterized by comprising a display element.
[0014]
A digital single-lens reflex camera according to the present invention is a digital single-lens reflex camera having an image pickup means, and is provided in a finder optical system and an image pickup optical path of the image pickup means, and guides a subject luminous flux to the finder optical system when observing a subject. A voltage determination that determines the power supply voltage by measuring the power supply voltage of the movable mirror that is at the first position and moves to the second position retracted from the imaging optical path during the photographing operation by the imaging means. And a display means for displaying the subject image picked up by the image pickup means, and the image displayed on the display element can be observed by sharing a part of the observation optical path of the finder optical system And when the power supply voltage is determined to be greater than or equal to a predetermined value by the voltage determination means, the movable mirror is moved while the release button is being operated. When it is determined that the power supply voltage is less than a predetermined value, the first mode in which the imaging operation by the imaging unit and the image display operation by the display unit are repeated while being moved to the position 2 can be executed. The second mode of performing an imaging operation for moving the movable mirror to the first position and the second position each time a release button is operated is provided. The predetermined value is a value of a power supply voltage that can execute a predetermined number of imaging operations by the imaging unit and an image display operation by the display unit.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
First, before describing embodiments of the present invention, features of a digital single-lens reflex camera according to the present invention will be described.
A digital single-lens reflex camera according to the present invention is a camera that captures a subject image with an image sensor such as a CCD, and a release button for instructing the start of an imaging operation is provided on the digital single-lens reflex camera. Is provided. As the imaging mode, “continuous imaging mode (hereinafter referred to as continuous shooting mode)” in which the imaging operation is repeated while the release button is kept pressed, and the imaging operation is executed only once by operating the release button. A sheet imaging mode (hereinafter referred to as a single shooting mode) "can be selected, and a mode button is provided as a mode setting means for that.
[0016]
Then, while the release button is operated in the state where the “continuous shooting mode” is selected by the mode setting means, the imaging operation is repeated with the subject image observation movable mirror being retracted out of the imaging optical path. It has become. Therefore, during continuous shooting, the camera operator cannot confirm the optical subject image by the finder optical system. However, in the digital single lens reflex camera according to the present invention, the captured image is displayed in the finder immediately after imaging. Display means is provided, and during continuous shooting, the photographer visually recognizes the electronic subject image with the display means instead of the optical subject image.
[0017]
The present invention will be described below with reference to the illustrated embodiments.
FIG. 1 is a perspective view of a digital single-lens reflex camera showing an embodiment of the present invention as seen from the back side.
As shown in FIG. 1, a release button 303 composed of a two-stage switch for instructing the start of an imaging operation is disposed on the right side of the top surface of the exterior housing 301 of the digital single-lens reflex camera 300. On the upper left side, a mode button 302 for setting the continuous shooting mode, the single shooting mode, or the resolution at the time of imaging is provided. Further, a finder eyepiece 304 for observing a subject image having a finder eyepiece 33 is disposed on the upper left side of the center of the back surface of the exterior housing 301, and the finder eyepiece. In the vicinity of 304, an after-mentioned notification display element 59 made of, for example, an LED is disposed.
[0018]
FIG. 2 is a block diagram showing an outline of a configuration of an electric circuit of the digital single-lens reflex camera of FIG.
As shown in FIG. 2, the digital single-lens reflex camera 300 includes a CPU 41 as a control unit that controls the operation sequence of the entire camera, a strobe light emitting unit 1, a photographing lens barrel 20, a movable mirror 24, a shutter 26, Solid-state imaging device 27 as an imaging means, finder 30, zoom / focus drive circuit 34, aperture drive circuit 35, mirror drive circuit 36, AF sensor drive circuit 37, shutter drive circuit 38, and focus detection device 39, switch input means 42, EEPROM 43, signal processing circuit 45, strobe control circuit 46, EPROM 47, SDRAM 48, flash memory 50, power supply battery 57, and voltage determination circuit 58 as voltage determination means. The main part is composed.
[0019]
The taking lens barrel 20 includes a positive lens 21 and a negative lens 23, and a diaphragm mechanism 22 is disposed between the positive lens 21 and the negative lens 23. The positive lens 21 and the negative lens 23 of the photographic lens barrel 20 are driven and controlled by a zoom / focus drive circuit 34, and the aperture mechanism 22 is driven and controlled by an aperture drive circuit 35.
[0020]
On the rear side of the negative lens 23 on the optical axis of the positive lens 21 and the negative lens 23, a movable mirror 24, a part of which is formed of a half mirror, is a mirror down position, which is a first position. It is arranged so as to be able to move to the mirror up position which is the second position. At the time of exposure, the movable mirror 24 jumps from the first position to the second position, which is the mirror-up position, toward the focusing screen 31 while rotating around the fixed shaft 24a, and is retracted from the photographing optical path. Yes. A sub mirror 25 is provided on the back of the central portion of the movable mirror 24 so as to reflect the subject light downward in the figure.
[0021]
Below the reflected optical axis of the sub-mirror 25, a separator optical system 28 for separating two images is disposed in a substantially vertical direction in the drawing, and a subject image is connected by the separator optical system 28. An AF sensor 29 is disposed at the image position, and an AF sensor driving circuit 37 is connected to the AF sensor 29. The sub mirror 25, the separator optical system 28, and the AF sensor 29 constitute a focus detection device 39. The focus detection device 39 detects the focal length of the subject by a known phase difference method.
[0022]
The AF sensor 29 is driven and controlled by an AF sensor driving circuit 37 in accordance with a control signal from a control circuit (CPU) 41 composed of a microprocessor described later. The CPU 41 obtains the interval between the two images (corresponding to the defocus amount of the positive and negative lenses 21 and 23) based on the two image signals generated by the AF sensor 29, and sets the photographing lens barrel 20 at the in-focus position. Drive amount data for driving the positive lens 21 and the negative lens 23 is calculated. Then, the zoom / focus drive circuit 34 is driven and controlled based on the calculated drive amount data to drive the positive and negative lenses 21 and 23 of the photographic lens barrel 20 to the in-focus position.
[0023]
The zoom / focus drive circuit 34 includes a drive source such as a known electromagnetic motor and ultrasonic motor, a driver circuit for controlling these drive sources, an encoder device for detecting the position of the lens, and the like. It is configured. In particular, the encoder for detecting the lens position is an encoder device that independently outputs the subject distance and the zoom focal length according to the lens position, and is a piece on the metal pattern provided on the outer surface of the lens frame. This is a contact type encoder that the brush slides. Further, a non-contact encoder may be used in which a black and white pattern is arranged on the outer surface of the photographing lens barrel 20 and the black and white pattern is detected by a photo reflector, and the driving amount of the photographing lens barrel 20 from the reference position is measured. Then, a so-called absolute distance encoder that detects the absolute position may be used.
[0024]
A finder optical system including a focusing screen (focusing screen) 31, a pentaprism 32, and a finder eyepiece 33 is disposed on the reflection optical path of the movable mirror 24. A finder device (hereinafter referred to as a finder) is obtained by adding an LCD monitor 8, which is a display means, a prism 54, a target lens 55, a photometric sensor 56, and a notification display element 59 which is a warning means to the finder optical system. 30). The subject light obtained by the positive lens 21 and the negative lens 23 of the photographic lens barrel 20 is reflected by the movable mirror 24 and imaged on the focusing screen 31. The photographer visually recognizes the optical subject image formed on the focusing screen 31 from the observation optical axis through the pentaprism 32 and the viewfinder eyepiece 33.
[0025]
The photometric sensor 56 is a sensor in which, for example, a light receiving surface is formed of a photodiode for measuring the luminance of an optical subject image formed on the focusing screen 31 through the target lens 55. The eyepiece lens 33 is disposed together with the target lens 55 at a position on the photometric axis that is decentered from the observation optical axis. The CPU 41 calculates subject luminance for exposure control by performing, for example, a predetermined weighted average calculation according to the output from the photometric sensor 56.
[0026]
The notification display element 59 is composed of, for example, an LED display element, and the LED is turned on by a display signal from the CPU 41, which will be described later, indicating that continuous shooting in continuous shooting mode cannot be performed due to a decrease in the power supply voltage of the power supply battery 57. This is for warning the photographer, and is arranged in the vicinity of the finder eyepiece 33 in the finder 30 as shown in FIG. The notification display element 59 may be disposed inside the finder eyepiece 304 (see FIG. 1). Moreover, you may use for warnings, such as camera shake generation | occurrence | production and exposure failure.
[0027]
Behind the movable mirror 24 on the optical axis of the positive lens 21 and the negative lens 23 of the photographic lens barrel 20, a shutter 26 and a solid-state image sensor (hereinafter referred to as an image sensor) 27 such as a CCD or CMOS imager are disposed. Has been.
[0028]
The shutter 26 is opened for a predetermined time by the shutter drive circuit 38 to form a subject image on a light receiving surface (not shown) of the image sensor 27. That is, the movable mirror 24 is raised to the second position in order to retract from the optical axes of the positive and negative lenses 21 and 23 under the driving of the mirror driving circuit 36, and the shutter 26 is based on the driving control of the shutter driving circuit 38. In the open state, a subject image is formed on the light receiving surface of the image sensor 27, and an imaging operation is performed. When the continuous shooting mode is set by a mode button of the switch input means 42 described later, the image pickup operation by the image pickup device 27 is continuously performed while the movable mirror 24 is raised (moved) to the second position. Done.
[0029]
The zoom / focus drive circuit 34, the aperture drive circuit 35, the mirror drive circuit 36, the AF sensor drive circuit 37, and the shutter drive circuit 38 are connected to a CPU 41 constituted by a microprocessor via a data bus 52. The CPU 41 is connected to a switch input means 42 and an EEPROM 43 which is a nonvolatile memory via a data bus 52.
[0030]
The switch input means 42 includes a first release switch that is turned on in conjunction with a half-pressing operation of a release button 303 (see FIG. 1) of the camera, a second release switch that is turned on in conjunction with a deep-pressing operation of the button, It is composed of a plurality of switches such as a switch interlocking with the power switch of the camera, a mode switch interlocking with the mode button 302 (see FIG. 1) of the camera for switching between the single shooting mode and the continuous shooting mode. Then, an operation signal based on the switch operation of any one of the switch input means 42 is supplied to the CPU 41.
[0031]
The EEPROM 43 is a non-volatile semiconductor memory, and the CPU 41 uses an adjustment value for each camera necessary for shipment while suppressing variations among cameras in the factory, and an output from the photometric sensor 56. A coefficient for defining the amount of light is stored.
[0032]
When the first release switch is turned on, the CPU 41 drives and controls the AF sensor drive circuit 37, calculates the distance between the two images on the AF sensor 29, and drives and controls the zoom / focus drive circuit 34 from the distance data. Thus, the focus adjustment of the positive lens 21 and the negative lens 23 of the photographing lens barrel 20 is performed.
[0033]
Further, when the second release switch is turned on, the CPU 41 drives and controls the mirror drive circuit 36 to move the movable mirror 24 to the second position from the optical axis, and based on the output of the photometric sensor 56. Based on the subject luminance information, an appropriate aperture value and shutter time are obtained, the diaphragm mechanism 22 is driven via the aperture drive circuit 35 with the obtained aperture value, and the shutter time is obtained via the shutter drive circuit 38. Then, the shutter 26 is driven. Further, the amount of current (light quantity) supplied to the backlight 8b is determined with reference to the coefficient stored in the EEPROM 43. Further, a display signal is output to the notification display element 59.
[0034]
When the subject image is formed on the light receiving surface of the image sensor 27 by the opening operation of the shutter 26, the subject image is converted into an analog video signal, and further converted into a digital video signal in the signal processing circuit 45.
[0035]
The signal processing circuit 45, which will be described in detail later with reference to FIG. 3, includes an RISC processor, a color processor, and a JPEG processor, and includes images such as compression / decompression processing, white balance processing, and edge enhancement processing of the digital video signal. Processing, conversion processing to a composite signal (luminance signal, color difference signal) output to the LCD monitor 8 described later, and the like are performed.
[0036]
Further, the CPU 41 and the signal processing circuit 45 are connected via a communication line 53, and control signals such as video signal capture timing and data are transmitted and received via the communication line 53.
[0037]
The composite signal generated by the signal processing circuit 45 is output to the LCD monitor 8 in the finder 30 to display an electronic subject image. The LCD monitor 8 is disposed outside the third reflecting surface 32 a of the pentaprism 32. The LCD monitor 8 includes an LCD (liquid crystal display element) 8a that is a display element for displaying an image, and a backlight 8b of, for example, a white LED for illuminating the display surface of the LCD 8a from the rear. Has been. When the continuous shooting mode is set by a mode button of the switch input means 42 described later, the image display operation by the LCD monitor 8 is continuously performed while the movable mirror 24 is raised (moved) to the second position. To be done.
[0038]
The third reflecting surface 32 a of the pentaprism 32 is a half mirror, and a prism 54 including a convex lens surface 54 a is disposed between the pentagonal prism 32 and the LCD monitor 8. The LCD 8a of the LCD monitor 8 is positioned optically equivalent to the focusing screen 31 by the convex lens surface 54a. In the state where the movable mirror 24 is raised from the first position to the second position and the optical observation optical path is blocked, the image displayed on the LCD 8a can be observed. The brightness of the image displayed on the LCD 8a can be adjusted by changing the current supply amount of the white LED of the backlight 8b.
[0039]
The signal processing circuit 45 is connected to an EPROM 47, an SDRAM (Synchronous Dynamic Random Access Memory) 48, and a flash memory 50 via a data bus 51.
[0040]
The EPROM 47 stores a program to be processed by a processor included in the signal processing circuit 45. The SDRAM 48 is a memory that temporarily stores image data before image processing and image data during image processing. Therefore, as will be described later, when the continuous shooting mode is set, the continuously captured image data is temporarily stored in the SDRAM 48. The flash memory 50 is a non-volatile memory that stores finally finalized image data. Here, the SDRAM 48 is a volatile temporary storage means that can operate at high speed, but the stored contents disappear when the power supply is stopped. On the other hand, the flash memory 50 is a non-volatile storage means, and the stored contents are preserved even if the power of the camera is turned off at a low speed. Therefore, as will be described later, after the continuous imaging is completed, the image data stored in the SDRAM 48 is sequentially stored in the flash memory 50.
[0041]
The power battery 57 is for supplying the output voltage to each drive circuit via a constant voltage circuit (not shown), and a part of the output voltage is A / D converted by a voltage determination circuit 58 to be described later. It is output to the CPU 41.
[0042]
The voltage determination circuit 58 includes an A / D conversion circuit (not shown), and measures the voltage of the power supply battery 57 when the continuous shooting mode is set by the mode button 302 of the switch input means 42. Then, it is determined whether or not the voltage of the power source battery 57 is equal to or higher than a predetermined value α. The predetermined value α refers to the maximum number of images that can be temporarily stored in the SDRAM 48 (hereinafter referred to as the number of images that can be continuously imaged n) (the number of imaging operations) and the image display operation on the LCD monitor 8. Is a voltage value of the power supply battery 57 that can be executed continuously, measured at the production stage, and stored in the EEPROM 43. Note that the number n of images that can be continuously captured is a value obtained by dividing the capacity of the SDRAM 48 by the amount of uncompressed image data that has been imaged.
[0043]
Next, the strobe light emitting unit 1 will be described. The strobe light emitting unit 1 includes a light emitting panel 3, a reflector 18, a light emitting discharge tube 19, and a trigger circuit 44. The strobe light emitting unit 1 is sealed in the light emitting discharge tube 19 by a trigger signal output from the trigger circuit 44. The xenon gas is excited to emit light, and the light is reflected by the reflector 18 and further passes through the light emitting panel 3 and is irradiated toward the subject. Although not shown, the trigger circuit 44, the light-emitting discharge tube 19, the reflector 18 and the light-emitting panel 3 are configured to pop up from the camera body, for example. The trigger circuit 44 is connected to the strobe control circuit 46. The strobe control circuit 46 controls charging of a strobe main capacitor (not shown) and a light emission instruction to the trigger circuit 44 under the control of the CPU 41.
[0044]
FIG. 3 is a block diagram showing a schematic configuration of the electric circuit of the signal processing circuit 45 in FIG. 2 and peripheral circuits connected thereto.
[0045]
The signal processing circuit 45 includes a CPU 100 as a control circuit that controls signal processing operations, and a plurality of circuits that are connected to the CPU 100 and operate according to control signals from the CPU 100. Further, as shown in FIG. 1 described above, the CPU 100 is connected to the camera sequence control CPU 41 via the communication line 53, and each circuit in the signal processing circuit 45 based on the control signal transmitted from the CPU 41. To control. As will be described later, based on the information on the current number of images that can be captured and the information about the number of images that can be continuously captured n output from the CPU 41, the information on the number of images that can be continuously captured and the number of images that can be continuously captured n is superimposed on the LCD monitor 8. An instruction signal is transmitted to the video decoder 104 for display.
[0046]
The first image processing circuit 101 drives the imaging device 27 in accordance with the driving conditions set by the CPU 100, and performs a front-end processing circuit that A / D converts the analog video signal output from the imaging device 27 to generate a digital video signal. It is. Further, the digital video signal is corrected based on the pixel signal of the light shielding portion of the image sensor 27.
[0047]
The thinning / extraction processing circuit 102 thins the digital video signal output from the first image processing circuit 101 (processing that reduces the resolution) to obtain a second image processing circuit 106, a third image processing circuit. To 103. The digital video signal output to the third image processing circuit 103 is a signal of an electronic subject image displayed on the LCD monitor 8 when shooting in the continuous shooting mode.
[0048]
Here, the degree of thinning of the digital video signal output to the second image processing circuit 106 is instructed by the CPU 100 according to the resolution set by the user with the mode button 302 (see FIG. 1). The degree of thinning of the digital video signal output to the third image processing circuit 103 is instructed by the CPU 100 according to the resolution suitable for image display. The thinning / extraction processing circuit 102 extracts a part of the digital video signal and outputs it to a white balance processing circuit (hereinafter referred to as WB processing circuit) 105. The CPU 100 instructs the extraction method.
[0049]
The WB processing circuit 105 outputs white balance information (WB information) for adjusting the color balance (white balance) of the image. This WB information is directly sent to the third image processing circuit 103. The image is sent to the second image processing circuit 106 via the CPU 100.
[0050]
The third image processing circuit 103 is a circuit that generates an image for display on the LCD monitor 8. The digital video signal is subjected to γ correction, data bit number reduction, color adjustment based on WB information, RGB signal to YCbCr signal. This is a simple post-stage processing circuit that performs known processing such as conversion. In general, in order to repeatedly display captured images on the LCD monitor 8, the processing by software often cannot keep up with the speed. Therefore, all image processing for display is processed by the third image processing circuit 103 in hardware.
[0051]
The video decoder 104 converts the YCbCr signal of the digital video signal into an NTSC signal to form the electronic subject image, and displays the electronic subject image on the LCD 8 of the LCD monitor 8. In addition, in accordance with an instruction from the CPU 100, as shown in FIG.
[0052]
The second image processing circuit 106 is a circuit that generates the digital video signal to be stored in the flash memory 50. The second image processing circuit 106 performs γ correction, reduction of the number of data bits of the digital video signal, color adjustment based on WB information, RGB signal This is a post-processing circuit that performs known processes such as conversion from the YCbCr signal, defective pixel correction of the image sensor 27, smear correction, hue and chromaticity.
[0053]
The JPEG compression / decompression processing circuit 107 performs JPEG compression when reading the digital video signal processed by the second image processing circuit 106 in the flash memory 50, or reads out the JPEG image stored in the flash memory 50. This is a circuit for stretching.
[0054]
Next, the operation sequence of the CPU 41 will be described with reference to FIG.
4 shows the digital single-lens reflex camera shown in FIG. 2, in which the continuous shooting mode is set by the mode button 302 (see FIG. 1) of the switch input means 42, and the release button 303 (see FIG. 1) of the switch input means 42. 5 is a flowchart showing an imaging operation executed after half-pressing operation (first release-on operation). This flowchart is a subroutine called in the main flowchart of the CPU 41. Since the main flowchart of the CPU 41 is a conventionally known technique, the description thereof is omitted here.
[0055]
In step S <b> 1, the photometric sensor 56 is driven and controlled via the target lens 55 to perform photometry, and the luminance information of the subject is measured using the output of the photometric sensor 56. Then, the exposure amount (the aperture amount of the aperture mechanism 22 and the shutter speed of the shutter 26) is calculated from the luminance information in accordance with a predetermined arithmetic program, and then the process proceeds to step S2.
[0056]
In step S2, the AF sensor 29 is driven and controlled via the AF sensor drive circuit 37, and the defocus amounts of the imaging lenses 21 and 23 are measured. Then, based on the distance measurement value, the focusing operation of the imaging lenses 21 and 23 is performed, and the process proceeds to step S3.
[0057]
In step S3, it is determined whether or not the camera operator has pressed down the release button of the switch input means 42 based on whether or not the second release switch is on. If the second release switch is not turned on, the process branches to step S19.
[0058]
In step S19, it is determined whether or not the camera operator next presses the release button halfway depending on whether or not the first release switch is on. If the first release switch is on, it is determined that the release button is half-pressed, and the process returns to step S3. On the other hand, if the first release switch is not on, it is considered that the camera operator has released his / her finger from the release button, and the process returns to the main flow as it is.
[0059]
Returning to step S3, if the second release switch is turned on, it is determined that the release button is pressed down and the process proceeds to step S4. In step S4, the power battery 57 from the voltage determination circuit 58 (whichever 2) is read, it is determined whether or not the voltage is equal to or greater than the predetermined value α, and the process proceeds to step S5.
[0060]
In step S5, the movable mirror 24 is retracted from the first position to the outside of the imaging optical path (mirror up) via the mirror driving circuit 36, and the process proceeds to step S6. Based on the voltage determination result of the power supply battery 57 in step S4, it is determined whether or not continuous imaging in the continuous shooting mode which is the first mode is possible. If the voltage of the power battery 57 is equal to or higher than the predetermined value α and continuous imaging is possible, the process proceeds to step S7.
[0061]
In step S7, based on the aperture amount calculated in step S1, the aperture mechanism 22 performs the aperture operation through the aperture drive circuit 35, and the process proceeds to step S8.
[0062]
In step S <b> 8, the CPU 41 sends a signal for instructing the start of continuous imaging to the signal processing circuit 45. The signal processing circuit 45 receives this signal, starts the imaging operation (integration operation) of the image sensor 27, and then proceeds to step S9.
[0063]
In step S9, the shutter 26 is opened and closed based on the shutter speed (the opening and closing time of the shutter 26) calculated in step S1, and the process proceeds to step S10.
[0064]
In step S10, after closing the shutter 26, a signal for instructing the image processing to be stopped is sent to the signal processing circuit 45. Upon receiving this signal, the signal processing circuit 45 terminates the integration operation in the image sensor 27, reads out the video signal from the image sensor 27, converts it into the above-described digital video signal, and image processing associated therewith. Is executed, and the process proceeds to step S11.
[0065]
In step S <b> 11, the CPU 41 sends a control signal instructing the signal processing circuit 45 to store and display the digital video signal. Upon receiving this signal, the signal processing circuit 45 temporarily stores the digital video signal in order in the continuous shooting data storage area of the SDRAM 48 and converts the data into a composite signal (luminance signal, color difference signal). Then, this composite signal is supplied to the LCD monitor 8, and the captured electronic subject image is displayed on the LCD 8a. Thereafter, the process proceeds to step S12.
[0066]
In step S12, it is determined whether or not the number of captured images has reached the above-described continuously captureable number n. If the number of continuously imageable images n has been reached, the process jumps to step S15. If the number of continuously imageable images n has not been reached, the flow proceeds to step S13.
[0067]
In step S13, the CPU 100 (see FIG. 3) of the signal processing circuit 45 is instructed to superimpose the display indicating the current number of images to be captured and the number of continuously imageable images n on the LCD 8a of the LCD monitor 8 during continuous shooting. . As a result of this instruction, as shown in FIG. 5, for example, when the current number of images to be captured is 3 and the number of images that can be continuously captured is 8, the display 201 of 3/8 is displayed on the LCD 8a of the LCD monitor 8 during continuous shooting. Is superimposed. Thereafter, the process proceeds to step S14.
[0068]
In step S14, it is checked whether the second release switch is off. If it is off, it is determined that the camera operator is going to end continuous shooting, and the process proceeds to step S15. On the other hand, if not OFF, the process returns to step S8, and steps S8 to S14 are repeated until the second release switch is turned OFF. That is, if the second release switch is not turned off at this time, continuous shooting is continued, and the electronic subject image captured immediately before is displayed in the finder 30 sequentially like a moving image.
[0069]
In step S15, the signal processing circuit 45 is instructed to end the display. Upon receiving this signal, the signal processing circuit 45 stops the display on the LCD 8a, turns off the backlight 8b, and proceeds to step S16.
[0070]
In step S16, the aperture mechanism 22 is returned from the aperture state to the open state via the aperture drive circuit 35, and the process proceeds to step S17. In step S17, the movable mirror 24 is moved to the first position via the mirror drive circuit 36. After returning to a certain imaging optical path (mirror down), the process proceeds to step S18. Further, in step S18, the continuous shot image temporarily stored in the SDRAM 48 as described above is sent to the flash memory 50 to the signal processing circuit 45. To store in the predetermined storage area, and then returns. At this time, depending on the capacity of the captured image, it may be stored in the flash memory 50 after being JPEG compressed by the JPEG compression / decompression processing circuit 107 (see FIG. 3).
[0071]
Returning to step S6, if the voltage of the power source battery 57 is not equal to or greater than the predetermined value α, that is, less than the predetermined value α, the process branches to step S20 and is connected to the notification display element 59 (see FIG. 2). A display signal for warning that copying cannot be performed is output. In response to this signal, the LED of the notification display element 59 is turned on. Thereafter, the process proceeds to step S21.
[0072]
In step S21, an imaging operation in the single shooting mode is executed. First, the diaphragm mechanism 22 is narrowed down via the diaphragm driving circuit 35 based on the diaphragm amount calculated in step S1, and the process proceeds to step S22.
[0073]
In step S22, a signal instructing to start imaging is sent to the signal processing circuit 45. The signal processing circuit 45 receives this signal, starts the imaging operation (integration operation) of the imaging device 27, and proceeds to step S23.
[0074]
In step S23, the shutter 26 is opened and closed based on the shutter speed (opening and closing time of the shutter 26) calculated in step S1, and the process proceeds to step S24.
[0075]
In step S24, after closing the shutter 26, the signal processing circuit 45 is sent a signal instructing to stop imaging. Upon receiving this signal, the signal processing circuit 45 terminates the integration operation of the image sensor 27, reads out a video signal from the image sensor 27, converts it into a digital video signal, and executes image processing associated therewith.
[0076]
In step S25, the CPU 41 sends a control signal for instructing the signal processing circuit 45 to store the digital video signal. In the single shooting mode, it is not necessary to temporarily store the digital video signal in the SDRAM 48 as in the continuous shooting mode. Therefore, the signal processing circuit 45 receives this control signal and sends the digital video signal to the predetermined memory of the flash memory 50. Store in the storage area. In the single shooting mode, the electronic subject image is not displayed in the viewfinder 30 as in the continuous shooting mode. Thereafter, the process proceeds to step S26.
[0077]
In step S26, the aperture mechanism 22 is returned from the aperture state to the open state via the aperture drive circuit 35, and the process proceeds to step S27. In step S27, the movable mirror 24 is moved to the first position via the mirror drive circuit 36. After returning to a certain imaging optical path (mirror down), the process proceeds to step S28.
[0078]
In step S28, it is checked whether or not the first release switch is off. If not, this check is repeated. This is to prevent the next imaging operation from being performed in the single shooting mode until the camera operator removes the finger from the release button. If it turns off, it returns to the main routine.
[0079]
As described above, in the digital single-lens reflex camera 300 showing one embodiment of the present invention, when the continuous shooting mode is set by the mode button 302 of the switch input unit 42, the voltage before the imaging operation is performed is set. The determination circuit 58 allows the voltage of the power supply battery 57 to be temporarily stored in the SDRAM 48 for the maximum number n of continuous images that can be imaged and the image display operation on the LCD monitor 8 to be continuously executed. It is determined whether or not it is equal to or greater than a predetermined value α), and if it is equal to or greater than the predetermined value α, a continuous imaging operation in the continuous shooting mode which is the first mode is executed. If the value is less than the predetermined value α, the notification display element 59 is turned on to notify the photographer that imaging in the continuous shooting mode cannot be performed, and the imaging operation in the single shooting mode which is the second mode is executed. I have to do it.
[0080]
Therefore, during continuous imaging in the continuous shooting mode, the digital single-lens reflex camera 300 does not stop suddenly due to a decrease in the voltage of the power supply battery 57, so that the photographer can look into the viewfinder eyepiece 33 without feeling uncomfortable. A subject image can be observed.
[0081]
In the present embodiment, the voltage of the power supply battery 57 can be stored in the SDRAM 48 temporarily. It is determined whether or not the value (predetermined value α) is equal to or greater than the predetermined value α, and if it is equal to or greater than the predetermined value α, the continuous imaging operation in the continuous shooting mode which is the first mode is executed. Even if the voltage of the power supply battery 57 is less than the predetermined value α, the single-shot mode is not set, and the value of the number n of continuous images that can be continuously taken is reduced by a value corresponding to the remaining voltage of the power supply battery 57 and continuous in the continuous-shot mode. Imaging may be performed.
[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a digital single-lens reflex camera that is easy to use for a photographer, in which there is no power remaining during continuous shooting, and the camera operation is prevented from suddenly stopping. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view of a digital single-lens reflex camera showing an embodiment of the present invention as seen from the back side;
FIG. 2 is a block diagram showing an outline of a configuration of an electric circuit of the digital single-lens reflex camera in FIG.
3 is a block diagram showing an outline of the configuration of an electric circuit of the signal processing circuit in FIG. 2 and peripheral circuits connected thereto;
FIG. 4 is a flowchart showing an imaging operation executed after half-pressing the release button of the switch input means in FIG.
FIG. 5 is a captured image diagram showing that the current number of images and the number of images that can be continuously captured are superimposed on the electronic subject image displayed during continuous shooting on the LCD in FIG. 2;
[Explanation of symbols]
8. LCD monitor (display means)
8a ... LCD (display element)
24 ... Movable mirror 27 ... Solid-state imaging device (imaging means)
30 ... Finder (finder optical system)
31 ... Focus plate (finder optical system)
32 ... Pental prism (finder optical system)
33. Viewfinder eyepiece (finder optical system)
57 ... Power supply battery 58 ... Voltage determination circuit (voltage determination means)
59 ... Notification display element (warning means)
300 ... Digital SLR camera 304 ... Viewfinder eyepiece

Claims (8)

In a digital single lens reflex camera having an imaging means,
Finder optics,
In the imaging optical path of the imaging means, it is at a first position for guiding the subject light beam to the finder optical system when observing the subject, and is retracted from the imaging optical path during the imaging operation by the imaging means. A movable mirror that moves to position 2,
Voltage determination means for measuring the power supply voltage of the camera and determining the power supply voltage;
A display unit that includes a display element for displaying a subject image captured by the imaging unit, and the image displayed on the display element can be observed by sharing a part of the observation optical path of the finder optical system;
A first mode that repeats an imaging operation by the imaging unit and an image display operation by the display unit while moving the movable mirror to the second position according to a determination result of the voltage determination unit; A selection means for selecting any one of a second mode in which an imaging operation for moving the movable mirror to the first position and the second position without performing a display operation;
A digital single-lens reflex camera characterized by comprising: The selection means can select the first mode when the voltage determination means determines that the power supply voltage is equal to or higher than a predetermined value, and the second mode when it is determined that the power supply voltage is lower than the predetermined value. The digital single-lens reflex camera according to claim 1, wherein the digital SLR camera is selected. 3. The digital single-lens reflex camera according to claim 2, wherein the predetermined value is a power supply voltage value at which a predetermined number of imaging operations by the imaging unit and an image display operation by the display unit can be continuously performed. camera. 2. The voltage determination unit, prior to an imaging operation by the imaging unit, performs a voltage measurement of a power source and an operation of determining whether or not the power source voltage is equal to or higher than the predetermined value. Or the digital single-lens reflex camera of 2. The digital single-lens reflex camera according to claim 1, further comprising warning means for notifying a photographer that the second mode has been selected by the selection means. 6. The digital single-lens reflex camera according to claim 5, wherein the warning means is constituted by a display element provided in a viewfinder eyepiece. In a digital single lens reflex camera having an imaging means,
Finder optics,
It is in the imaging optical path of the imaging means, and is in a first position for guiding the subject light flux to the finder optical system when observing the subject, and is retracted from the imaging optical path during the photographing operation by the imaging means. A movable mirror that moves to position 2,
Voltage determination means for measuring the power supply voltage of the camera and determining the power supply voltage;
A display unit that includes a display element for displaying a subject image captured by the imaging unit, and the image displayed on the display element can be observed by sharing a part of the observation optical path of the finder optical system;
Comprising
When it is determined by the voltage determination means that the power supply voltage is equal to or higher than a predetermined value, the image pickup means keeps moving the movable mirror to the second position while the release button is being operated. When the first mode in which the imaging operation and the image display operation by the display unit are repeated can be executed, and it is determined that the power supply voltage is less than a predetermined value, the movable mirror is moved each time the release button is operated. A digital single-lens reflex camera characterized by executing a second mode in which an imaging operation for moving to the first position and the second position is performed. 8. The digital single-lens reflex camera according to claim 7, wherein the predetermined value is a value of a power supply voltage capable of executing a predetermined number of imaging operations by the imaging unit and an image display operation by the display unit.

Images