JP2002300435A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the low speed of forward and backward movement of a QR mirror to a photographing light path being bottleneck of high-speed continuous photographing, in a digital single lens reflex type imaging device. SOLUTION: This device is provided with an optical switching means, that is selectively arranged at an optical observation position for leading an objective light to an optical finger and at an imaging position, for allowing the objective light to be received by an imaging element 6, and an electronic finder 13. In a static image independent photographing mode, an optical switching means is moved between both positions, to start the observation of the optical finder and imaging by the imaging element successively, and in a continuous photographing mode, and optical switching means is arranged at the optical observation position, before continuous photographing to start the observation of the optical finder, and the optical switching means is held at the photographing position during continuous photographing, to start the observation of the electronic finder. Furthermore, in an animation photographing mode, the observation of the optical finder is started before animation photographing, and the optical switching means is held at the photographing position during animation photographing to start the observation of the electronic finder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching means such as a mirror which is selectively disposed at a position for guiding the subject light having passed through a photographing optical system to an optical finder and a position for receiving the subject light at an image sensor. The present invention relates to a digital single-lens reflex type imaging device having the same.

[0002]

2. Description of the Related Art Conventionally, a single-lens reflex camera using a silver halide film is disposed in a photographing optical path during finder observation, guides subject light to an optical finder, and retracts from the photographing optical path during photographing to perform film exposure. Q to enable
It has an R (quick return) mirror.

In this single-lens reflex camera, since a subject image is observed using a photographing light beam, a high-quality finder image having no parallax, a high field rate, and a parallax is obtained as a TTL optical finder.

On the other hand, in recent years, digital imaging has been advanced, and solid-state imaging devices such as CCDs and CMOSs have been increasingly used in place of silver halide films. Furthermore, with the advancement of semiconductor technology, the miniaturization of solid-state imaging devices has progressed, and many devices with small screen sizes and megapixels have appeared,
The resolution is approaching the silver halide film to some extent.

In particular, those using these image pickup devices differ from those using a silver halide film in that an image of a subject is exposed on the surface of the image pickup device and written as a recording image on a recording medium. By refreshing the photoelectric conversion amount, it is possible to prepare for the next exposure.

For this reason, a digital still camera does not require a film feeding mechanism such as a silver halide film camera, and high-speed continuous shooting which a camera using a silver halide film is not good at, and a camera using a silver halide film cannot. Movie shooting that was previously possible is now possible.

[0007] Regarding the control of the QR mirror of the digital single-lens reflex camera, for example, Japanese Patent Laid-Open No.
And JP-A-2000-111789 and JP-A-11-146235.

[0008]

As described above, the digital single-lens reflex camera does not require a film feed, and the electric recording speed of a photographed image has been improved. Suitable for.

However, since the forward and backward movement speed of the QR mirror with respect to the photographing optical path is equivalent to that of the film camera,
This is a bottleneck for high-speed continuous shooting.

Accordingly, the present invention not only enables single and continuous shooting of still images as in the case of conventional single-lens reflex film cameras, but also achieves high-speed continuous shooting which cannot be achieved with single-lens reflex film cameras. Enabled
It is another object of the present invention to provide an imaging device capable of capturing moving images.

[0011]

In order to achieve the above object, the present invention provides an optical observation position for guiding a subject light passing through a photographing optical system to an optical finder and an imaging position for receiving the subject light by an image sensor. In an image pickup apparatus having an optical switching means selectively disposed in the camera and an electronic finder for displaying a photographed image by the image pickup device, and capable of setting a single photographing mode and a continuous photographing mode for still image photographing, a single photographing mode is provided. Is set, the optical switching means is moved between the optical observation position and the imaging position to sequentially perform the subject image display by the optical viewfinder and the imaging by the imaging device, and the continuous imaging mode is set. Before continuous shooting, place the optical switching means at the optical observation position to display the subject image using the optical viewfinder, and turn on the light during continuous shooting. The switching means is held at the imaging position and the subject image is displayed by the electronic viewfinder. When the moving image shooting mode is set, the optical switching means is arranged at the optical observation position before shooting the moving image, and the object is displayed by the optical viewfinder. There is provided control means for displaying an image and holding the optical switching means at the image pickup position during moving image shooting to display a subject image by the electronic viewfinder.

That is, in the single photographing mode, the optical switching means is moved between the optical observation position and the photographing position for each photographing as in the conventional film camera, while in the continuous photographing mode, the optical switching means is switched during the continuous photographing. By holding the unit at the imaging position, continuous shooting at a higher speed is enabled as compared with the case where the optical switching unit is moved for each shooting, and continuous shooting is performed while observing the subject by displaying the subject with the electronic viewfinder. It becomes possible.

In addition, before the continuous photographing, the optical switching means is arranged at the optical observation position to display the subject image by the optical finder, and the electronic finder does not display the subject image. Therefore, even when the electronic finder display is unnecessary. It is possible to prevent useless power consumption by performing electronic finder display.

In the moving image photographing mode, similarly to the continuous photographing mode, before moving image photographing, the optical switching means is arranged at the optical observation position to display a subject image by the optical viewfinder, and during moving image photographing, the optical switching means is operated. By holding the camera at the imaging position and displaying the subject image by the electronic viewfinder, wasteful power consumption is suppressed.

[0015]

(First Embodiment) FIGS. 1 and 2
1 shows a schematic configuration of a digital single-lens reflex camera (imaging device) according to an embodiment of the present invention.

In these figures, reference numeral 9 denotes a camera main body, and reference numeral 1 denotes an exchangeable photographing lens which is detachable from the camera main body 1.

Numeral 2 denotes a QR (quick return) mirror (optical switching means) comprising a half mirror, which is inclined by a mirror driving mechanism (not shown) in a photographing optical path as shown in FIG. The arrangement can be switched between an optical observation position for guiding to the optical finder side and an imaging position where the imaging device 6 is retracted outside the imaging optical path and receives an imaging light beam to be described later, as shown in FIG.

Reference numeral 3 denotes a sub-mirror, which is deployed with respect to the QR mirror 2 in a state where the QR mirror 2 is disposed at the optical observation position and is obliquely provided in the photographing optical path, and in a state where the QR mirror 2 is disposed at the imaging position. Is folded with respect to the QR mirror 2 and retracted outside the photographing optical path. The sub-mirror 3 is obliquely provided in the photographing optical path, so that the QR mirror 2
Is reflected toward the focus detection device 4 arranged below the camera body.

Reference numeral 5 denotes a shutter device. In the camera of the present embodiment, the mechanical shutter device 5 is used for still image shooting, but the electronic shutter is used for moving image shooting. Reference numeral 20 denotes a low-pass filter and an infrared cut filter.

Reference numeral 6 denotes an image sensor, such as a CCD or a CM.
A solid-state imaging device such as an OS or an imaging tube such as a vidicon is used.

The focus detecting device 4 includes a field lens, a reflecting mirror, a secondary image forming lens, a stop, and a plurality of Cs arranged near the image forming plane of the light beam guided by the sub-mirror 3.
It comprises a line sensor made of a CD or the like, and detects a focus adjustment state of the photographing lens 1 by a so-called phase difference method.

Reference numeral 7 denotes a focusing plate disposed on a predetermined image forming plane of the photographing lens 1, and 8 denotes a pentaprism for bending a finder optical path.

Reference numerals 15 and 16 denote imaging lenses 15 for measuring the luminance of a subject in a finder observation screen (photographing screen).
And the photometric sensor 16, and the imaging lens 15 associates the focusing plate 7 with the photometric sensor via a reflected optical path in the pentaprism 8 in a conjugate manner.

Behind the exit surface of the pentaprism 8, an eyepiece 10 having a light combiner 10a is arranged.
It is used for observation of the focus plate 7 by the photographer's eyes 14.
The light combiner 10a is composed of, for example, a half mirror. An optical finder (or a finder optical system) is constituted by the focus plate 7 to the eyepiece 10.

Reference numeral 11 denotes a condenser lens, and reference numeral 12 denotes a finder display device having a light source. The luminous flux including image information such as characters emitted from the display device 12 in the finder is combined with the photographic luminous flux guided to the optical finder by the condenser lens 11 and the optical combiner 10a, and is guided to the photographer's eye 14 together with the photographic luminous flux. I will As a result, so-called superimposed display of photographing conditions and the like becomes possible.

Note that the display device 12 in the finder is
It is configured to include an LED light source for three colors of GB and a liquid crystal panel. A color display may be performed by turning on the LED light source in time series, or a color display may be performed by a cold cathode tube and a color liquid crystal panel. Further, it may be constituted by a color EL (electroluminescence) panel.

Reference numeral 13 denotes a liquid crystal monitor (electronic finder) attached to the back of the camera body 9.

FIG. 6 shows an electric circuit configuration of the camera. In FIG. 1, reference numeral 1 denotes a photographic lens;

The image sensor 4 is driven by a CPU 21 in the camera body 9 via a timing generator 28 and a driver 29 in response to a second stroke operation (full press operation) of a shutter button (not shown). The timing generator 28 also controls the analog processing circuit 24.
And the A / D conversion circuit 25 is controlled.

The signal charges stored in the image pickup device 4 are discharged by a driver 29 and input to an analog signal processing circuit 24 including an AGC circuit and a CDS circuit. After analog processing such as gain control and noise removal is performed on the analog image signal by the analog signal processing circuit 24, the analog image signal is converted into a digital signal by the A / D conversion circuit 25.

The digitally converted signal is, for example, ASI
It is guided to an image processing circuit 26 configured as C, where image pre-processing such as white balance adjustment and gamma correction is performed.

The white balance detection processing circuit includes a white balance sensor 32 that is a color temperature sensor, an A / D conversion circuit 31 that converts an analog signal from the white balance sensor 32 into a digital signal, and a white color sensor based on the digital color temperature signal. CPU 21 for generating balance correction signal
And

The white balance sensor 32 is composed of, for example, a plurality of photoelectric conversion elements having sensitivity to red R, blue B, and green G, respectively, and extracts partial white or converts the average light of all pixels to an achromatic color. To estimate the light source color temperature.
The CPU 21 determines R based on the outputs of the plurality of photoelectric conversion elements.
Calculate the gain and B gain.

In the present embodiment, the white balance sensor 32 is provided as a dedicated sensor.

The image data subjected to the image preprocessing is further subjected to a format process for JPEG compression or the like, and thereafter the image data is temporarily stored in the buffer memory 33. And finally JPE
The data is compressed at a predetermined ratio according to the G method or the like, and is recorded on a storage medium 30 such as a flash memory.

Reference numeral 19 denotes a photographic lens 1 according to a signal from the CPU 21 which calculates a required driving amount of the photographic lens 1 for reading a signal from the AF unit 15 and obtaining focus.
This is a lens control circuit that drives the focusing lens inside.

The camera body 9 is provided with a mode setting dial (not shown). The user operates the mode setting dial to operate a still image single shooting (single shooting) mode or a still image continuous shooting (continuous shooting). ) Mode and moving image shooting mode can be switched.

Next, the operation of the camera according to the present embodiment in the still image single shooting mode, the still image continuous shooting mode, and the moving image shooting mode will be described with reference to the flowcharts shown in FIGS.

Here, the operation from the case where the camera is in the shooting standby state will be described. In the photographing standby state, the QR mirror 2 of the camera is lowered to the optical observation position as shown in FIG.

In FIG. 3 to FIG. 5, the portions marked with are shown to be connected to each other.

First, the CPU 21 executes a step (S in the figure)
At 100, it is determined whether the shooting mode is the still image single shooting mode, the still image continuous shooting mode, or the moving image shooting mode. When the still image single shooting mode is set, the process proceeds to step 100a. When the still image continuous shooting mode is set, the process proceeds to step 200. When the moving image shooting mode is set, the process proceeds to step 300.

<Still Image Single Shooting Mode> Step 100
At a, when a shutter button (not shown) is pressed,
The still image shooting sequence is started, and the process proceeds to step 101.

The following step 101 and steps 103 to S
The operation of 105 is performed with time overlap. By overlapping temporally, the effect of reducing the shutter time lag can be obtained.

In step 101, the CPU 21 detects the brightness of the subject through the photometric sensor 16, and determines the shutter speed and the aperture value with reference to a predetermined program chart.

Next, in step 102, a signal is read from the AF unit 15, and a required driving amount of the photographing lens 1 is obtained by a predetermined calculation.

In this camera, a phase difference AF system widely used in an autofocus single lens reflex camera is used as an AF system.

In step 103, the CPU 21 sends the calculated lens extension amount to the lens control circuit 19. The lens control circuit 19 drives a lens drive motor (not shown) by an amount corresponding to the lens extension amount to move the focusing lens.

In step 104, defocus detection is performed again. If the defocus amount is within the focusing range, the focusing operation is terminated, and the flow advances to the next step 105. If the defocus amount is out of the focusing range, the lens extension amount is calculated again and the process returns to step 103. Thus, the determination of the final exposure amount and the focus adjustment are completed.

Next, in step 105, the CPU 21 drives the QR mirror 2 to the imaging position shown in FIG.

Next, in step 106, the electric charge of the image pickup device 6 is discarded to prepare for image pickup. And step 10
In step 7, the shutter unit 5 is driven, and an exposure operation is performed with the aperture value and the shutter speed determined in step 101. In addition,
In the exposure operation, the mechanical opening / closing operation of the optical path by the shutter device 5 and the electronic shutter operation of starting and ending the accumulation of electric charges in the image sensor 6 are used together (the same applies to each shooting mode described later). Is).

Subsequently, at step 109, the electric charge accumulated from the image sensor 6 is taken out and temporarily stored as image data in a memory (not shown) in an image acquisition / storage circuit.

At this time, in step 110, the QR mirror 2 is returned to the optical observation position shown in FIG.

In step 111, the CPU 21
Causes image processing such as matrix processing, white balance processing, and gamma correction processing to be performed on the image data captured in the memory of the image capturing storage circuit.

Next, in step 112, the previous step 11
Image data formed as one color image by one image processing is compressed. In the present embodiment, JPEG compression using DCT and Huffman coding is performed.

In the next step 113, the compressed data is written to the nonvolatile memory 33 for storage. This completes the still image shooting sequence.

In the still image shooting mode, the viewfinder image disappears when the QR mirror 2 is moved up, as in the case of the conventional single-lens reflex camera of the QR mirror system, but it is instantaneous and poses no problem.

<Still Image Continuous Shooting (Continuous Shooting) Mode> In step 200, when a shutter button (not shown) is pressed, a still image continuous shooting sequence is started and the process proceeds to step 201.

The following step 201 and steps 203 to S
The operation of 205 is performed with time overlap. By overlapping temporally, the effect of reducing the shutter time lag can be obtained.

In step 201, the CPU 21 detects the brightness of the subject through the photometric sensor 16, and determines the shutter speed and the aperture value with reference to a predetermined program chart.

Next, in step 202, a signal is read from the AF unit 15, and a required driving amount of the photographing lens 1 is obtained by a predetermined calculation.

In step 203, the CPU 21 sends the calculated lens extension amount to the lens control circuit 19. The lens control circuit 19 drives a lens drive motor (not shown) by an amount corresponding to the lens extension amount to move the focusing lens.

In step 204, defocus detection is performed again. If the defocus amount is within the focusing range, the focusing operation is terminated, and the flow advances to the next step 205. If the defocus amount is out of the focusing range, the lens extension amount is calculated again, and the process returns to step 203. Thus, the determination of the final exposure amount and the focus adjustment are completed.

Next, in step 205, the CPU 21 drives the QR mirror 2 to the imaging position shown in FIG.

Next, in step 206, the electric charge of the image sensor 6 is discarded to prepare for imaging. And step 20
In step 7, the shutter unit 5 is driven, and an exposure operation is performed with the aperture value and the shutter speed determined in step 201.

Subsequently, at step 209, the electric charge accumulated from the image sensor 6 is taken out and temporarily stored as image data in a memory (not shown) in an image acquisition / storage circuit.

In the single photographing mode, the QR mirror 2
Is returned to the optical observation position shown in FIG. 1, but in the continuous shooting mode, the QR mirror 2 is kept at the imaging position shown in FIG.

In step 210, the CPU 21 causes the image data fetched into the memory of the image fetching and storing circuit to perform image processing such as matrix processing, white balance processing, and gamma correction processing. Step 2
In step 10a, image data for display on a liquid crystal viewfinder is created and sent to the liquid crystal monitor 13.

Next, in step 211, step 210
Image data formed as a single color image by the above image processing. In the present embodiment, JPEG compression using DCT and Huffman coding is performed.

In the next step 212, the compressed data is written to the nonvolatile memory 33 for storage.

In step 213, it is determined whether or not the shutter button has been turned off. If the shutter button has been turned on, the flow returns to step 206 to execute the next image shooting.

On the other hand, if the shutter button is turned off in step 213, the process proceeds to step 214, where the CPU 2
1 returns the QR mirror 2 to the optical observation position shown in FIG. Thus, the continuous shooting sequence ends.

As described above, in the present embodiment, in the continuous photographing mode, the QR mirror 2 is arranged at the optical observation position before the continuous photographing to enable the observation of the subject image by the optical finder, while the continuous photographing is started. Later, the QR mirror 2 is held at the image pickup position, and the subject image can be observed on the liquid crystal monitor 13.

Thus, the liquid crystal monitor 1 can be used before continuous shooting.
3, the power consumption can be reduced as compared with the case where the subject image is displayed, but the continuous shooting can be performed at a higher speed than when the QR mirror 2 is moved during the continuous shooting.

In the continuous photographing mode, the optical finder image disappears when the QR mirror 2 is moved up, but the finder observation by the liquid crystal monitor 13 is enabled, and the finder observation is not disabled.

<Moving Picture Shooting Mode> In step 300, when a shutter button (not shown) is pressed, a moving picture shooting sequence is started, and the flow advances to step 301.

The following steps 301 and 30
The operations of 3 to S305 are performed with time overlap. By overlapping temporally, the effect of reducing the shutter time lag can be obtained.

At step 301, the CPU 21 detects the luminance of the object by the photometric sensor 16, and determines an electronic shutter speed and an aperture value with reference to a predetermined program chart.

In step 302, the AF unit 15
The required driving amount of the photographing lens 1 is obtained by a predetermined calculation.

In step 303, the CPU 21 sends the calculated lens extension amount to the lens control circuit 19. The lens control circuit 19 drives a lens drive motor (not shown) by an amount corresponding to the lens extension amount to move the focusing lens.

In step 304, defocus detection is performed again. If the defocus amount is within the focusing range, the focusing operation is terminated, and the flow advances to the next step 305. If the defocus amount is out of the focusing range, the lens extension amount is calculated again and the process returns to step 303. Thus, the determination of the final exposure amount and the focus adjustment are completed.

Next, in step 305, the CPU 21 drives the QR mirror 2 to the image pickup position shown in FIG.

Next, in step 306, the shutter unit 5 is driven to start exposure. Further, in step 307, the electric charge of the image sensor 6 is discarded to prepare for imaging.

Subsequently, in step 308, step 3
The exposure operation is performed with the aperture value determined at step 01 and the electronic shutter speed. Then, in step 208, the electric charge stored in the image sensor 6 is taken out and temporarily stored as image data in a memory in the image taking and storing circuit.

Next, the CPU 21 causes the image data fetched into the memory of the image fetching and storing circuit in step 309 to perform image processing such as matrix processing, white balance processing, and gamma correction processing. In step 310, image data thinned out for display on a liquid crystal view finder is created and sent to the liquid crystal monitor 13.

Further, in step 311, step 3
In step 09, data formed as a moving image color image is compressed. In this embodiment, MPEG1, MP
Compress to EG2 or AVI data.

Next, in step 312, the compressed data is written to the non-volatile memory 33 for storage.

Until the shutter button is turned on again, steps 307 to 312 are repeated to continue shooting a moving image. When the shutter button is turned on in step 313, the process proceeds to step 314.

At step 314, the CPU 21 returns the QR mirror 2 to the optical observation position shown in FIG. Thus, the moving image shooting sequence ends.

As described above, even in the moving image shooting mode,
Before shooting a movie, place the QR mirror 2 at the optical observation position,
Since the finder image is not displayed on the liquid crystal monitor 13, the power consumption can be suppressed even before the start of shooting as compared with the case where the finder image is displayed on the liquid crystal monitor 13.

While the moving image is captured, the optical finder image disappears due to the raising of the QR mirror 2, but the finder observation by the liquid crystal monitor 13 becomes possible, and the finder observation is not disabled.

[0091]

As described above, according to the present invention,
In the still image single photographing mode, the optical switching means is moved between the optical observation position and the imaging position for each photographing as in the conventional film camera, while in the continuous photographing mode, the optical switching means is photographed during the continuous photographing. Since it is held in position,
There is no parallax, and it is possible to shoot a still image alone while looking at a high-quality optical finder image, and to perform continuous shooting at a higher speed than when moving the optical switching means during continuous shooting, In addition, continuous photographing can be performed while observing the subject by displaying the subject using the electronic viewfinder.

In addition, before the continuous photographing, the optical switching means is arranged at the optical observation position to display the subject image by the optical finder, and the electronic finder does not display the subject image. Therefore, even when the electronic finder display is unnecessary. It is possible to prevent useless power consumption by performing electronic viewfinder display.

Further, in the moving image shooting mode, as in the case of continuous shooting, before moving image shooting, the optical switching means is arranged at the optical observation position to display a subject image by the optical viewfinder. Is held at the imaging position, and the subject image is displayed by the electronic finder, so that a single-lens reflex digital imaging apparatus capable of capturing a moving image while suppressing unnecessary power consumption can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a digital single-lens reflex camera (before shooting) according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the camera (during shooting).

FIG. 3 is an operation flowchart when the camera shoots a still image alone.

FIG. 4 is an operation flowchart at the time of continuous shooting of a still image in the camera.

FIG. 5 is an operation flowchart when a moving image is shot by the camera.

FIG. 6 is a block diagram of an electric circuit of the camera.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photographing lens 2 QR mirror 3 sub-mirror 4 focus detection device 5 shutter device 6 image sensor 7 focus plate 8 pentaprism 9 camera body 10 eyepiece 11 condensing lens 12 viewfinder display 13 liquid crystal monitor 14 photographer's eye 15 imaging Lens 16 Photometry sensor 19 Lens control circuit 20 Infrared cut and low-pass filter 21 CPU 24 Analog signal processing circuit 25 A / D converter 26 ASIC circuit 27 JPEG compression circuit 28 Timing generator 29 Driver 30 PC card 31 AWB-A / D 32 White balance sensor 33 Non-volatile memory 34 Display driver

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁷ identification mark FI theme Court Bu (reference) G03B 19/02 G03B 19/02 19/12 19/12 F-term (reference) 2H018 AA21 AA32 BE00 2H054 AA01 CB20 CD03 2H081 AA37 DD00 2H104 AA12 5C022 AA00 AB67 AC02 AC03 AC09 AC52 AC54 AC78 CA00

Claims (4)

[Claims] An optical switching unit selectively disposed at an optical observation position for guiding the subject light having passed through the photographing optical system to an optical finder and an imaging position at which the subject light is received by an image sensor; An electronic finder for displaying a photographed image, wherein the photographing apparatus is capable of setting a single photographing mode and a continuous photographing mode with respect to still image photographing, wherein the optical switching means is provided when the single photographing mode is set. Is moved between the optical observation position and the imaging position to sequentially perform the subject image display by the optical viewfinder and the imaging by the imaging element.When the continuous imaging mode is set, before the continuous imaging, The optical switching means is arranged at the optical observation position to display an object image by an optical finder, and during continuous shooting, the optical switching means is moved forward. When the moving image shooting mode is set, the optical switching means is arranged at the optical observation position and the object image is displayed by the optical viewfinder. Display,
An image pickup apparatus, comprising: a control unit for holding the optical switching unit at the image pickup position during moving image shooting and displaying a subject image by an electronic finder. 2. The optical switching device according to claim 1, wherein the optical switching means is a mirror member capable of switching a position between the optical observation position in the imaging optical path and the imaging position outside the imaging optical path. Imaging device. 3. The imaging apparatus according to claim 1, wherein the imaging circuit including the imaging element has an electronic shutter function. 4. The imaging device according to claim 1, wherein a shutter device that mechanically blocks an optical path is disposed on a front surface of the imaging device.