JP2005352208A - Electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera in which the detection accuracy of a focusing position is improved as for the electronic camera of a contrast detection system that irradiates auxiliary light upon AF operation. <P>SOLUTION: The electronic camera is equipped with a color filter consisting of a plurality of colors of color filter elements corresponding to respective pixels, and comprises an imaging element which photoelectrically converts an object image according to a photographing optical system and produces an image signal; a focusing position detection part of detecting the position of the photographing optical system where a focus evaluation value of the object image calculated based on the image signal becomes maximum as a focusing position; an auxiliary light source which illuminates the object upon the detection operation according to the focusing position detection part; and a gain adjustment part which relatively enhances a gain relating to the output of a pixel corresponding to a color including wavelengths of illumination light by means of the auxiliary light source as for the gain relating to the output of the other pixel when illuminating the object with the auxiliary light upon the detection operation by means of the focusing position detection part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic camera that performs autofocus using auxiliary light.

Conventionally, as one of autofocus (AF) controls of an electronic camera, a focus evaluation value of a subject image is calculated based on an image signal generated by an image sensor, and a focus position of a photographing lens is determined based on the focus evaluation value. A contrast detection method for detecting is known.
With this contrast detection type electronic camera, the accuracy of AF decreases when shooting a dark subject. For this reason, when a dark subject is photographed with the above-described electronic camera, the gain of the image signal is uniformly amplified during the AF operation, or the subject is illuminated with auxiliary light during the AF operation.

Here, Patent Document 1 discloses a contrast detection type electronic camera that amplifies the gain of an image signal regardless of lighting of auxiliary light during AF operation. In particular, Patent Document 1 intends to amplify the red gain regardless of the lighting of the auxiliary light during the AF operation, and increase the sensitivity of the infrared component when the subject is a person to increase the AF accuracy.
Patent Document 2 discloses a contrast detection type electronic camera that emits auxiliary light having a wavelength in a color band that is most frequently included in a color filter of an image sensor.
Japanese Patent Laid-Open No. 2002-287013 JP 2003-287664 A

  However, when the gain of the image signal is uniformly amplified during the AF operation to increase the accuracy of AF without turning on the auxiliary light, there is room for improvement in that the noise component included in the image signal is amplified. There is. In particular, in Patent Document 1, since an infrared component of incident light is removed when an infrared cut filter is disposed in front of the light receiving surface of the image sensor, a significant improvement in AF accuracy can be expected in a general electronic camera. There was no problem.

On the other hand, when the auxiliary light is irradiated during the AF operation as in the above-mentioned Patent Document 2, the AF accuracy is improved to some extent, but further improvement of the AF accuracy is still demanded as the performance of the camera increases. . Here, if the gain of the image signal is uniformly amplified after irradiating the auxiliary light, an adverse effect due to amplification of the noise component in the image signal becomes a problem as described above.
The present invention is for solving the above-described problems of the prior art, and an object thereof is related to a contrast detection type electronic camera that emits auxiliary light during AF operation, and the electronic camera capable of further improving the accuracy of detecting a focus position. Is to provide.

  An electronic camera according to a first aspect of the present invention includes a color filter including a plurality of color filter elements corresponding to each pixel, and an image sensor that photoelectrically converts a subject image by a photographing optical system to generate an image signal; A focus position detection unit that calculates a focus evaluation value of the subject image based on an image signal and detects a position of the photographing optical system that maximizes the focus evaluation value as a focus position; and the focus position detection unit In the case of illuminating the subject with the auxiliary light source that illuminates the subject during the detection operation and the auxiliary light source during the detection operation by the in-focus position detection unit, the color includes the wavelength of the illumination light from the auxiliary light source. And a gain adjusting unit that increases a gain related to the output of the corresponding pixel relatively to a gain related to the output of the other pixels.

  According to a second aspect of the present invention, there is provided an electronic camera including a color filter including a plurality of color filter elements corresponding to each pixel, an image sensor that photoelectrically converts a subject image by a photographing optical system to generate an image signal, and a subject When the subject is illuminated with the auxiliary light source, the focus evaluation value of the subject image is calculated based only on the image signal corresponding to the color including the wavelength of the illumination light from the auxiliary light source. And an in-focus position detecting unit that detects the position of the photographing optical system that maximizes the focus evaluation value as an in-focus position.

According to a third aspect of the present invention, in the second aspect of the present invention, the gain relating to the output of the pixel corresponding to the color including the wavelength of the illumination light by the auxiliary light source is set to the other pixels during the detection operation of the focus position detection unit It further has a gain adjustment part which raises with respect to the gain about the output of No ..
According to a fourth aspect of the present invention, in the first or third aspect of the present invention, the electronic finder unit further displays an image based on the image signal, and the electronic finder unit emits the gain when the auxiliary light source emits light. The image is generated by readjusting the gain of the image signal so as to cancel the gain change of the image signal in the adjustment unit.

  According to a fifth aspect of the present invention, in the first or third aspect of the present invention, the electronic finder unit further displays an image based on the image signal, and the electronic finder unit emits the auxiliary light when the auxiliary light source emits light. The image generated immediately before light emission from the light source is displayed for a predetermined time.

  In the electronic camera of the present invention, when the auxiliary light is emitted when detecting the in-focus position, the output of the pixel corresponding to the color including the wavelength of the illumination light is relatively improved, so that the in-focus position for the dark subject Detection accuracy is significantly improved.

(Description of the first embodiment)
FIG. 1 is a block diagram of the electronic camera of the first embodiment (corresponding to the electronic camera of claims 1 and 3).
The electronic camera according to the first embodiment includes a photographing lens system 1, a focus motor 2, an image sensor 3, an analog signal processing unit 4, an A / D conversion unit 5, a digital signal processing unit 6, and an electronic viewfinder unit. 7, an auxiliary light source 8, a CPU 9, and an operation member 10.

The photographic lens system 1 includes a plurality of lens groups including a focusing lens for adjusting the focal position and a lens driving mechanism. The taking lens system 1 is driven and adjusted by a focus motor 2.
The image sensor 3 is arranged on the image space side of the photographic lens system 1. The image pickup device 3 of the first embodiment includes a function of an image pickup unit that records a subject image, a function of a light receiving unit of a focus detection unit, and a function of a split photometry unit that acquires luminance information of an object scene. Yes.

  The image sensor 3 includes a pixel surface on which a large number of pixels having light receiving elements are arranged in a plane, and an output unit that converts charges accumulated in each pixel into a voltage and outputs the voltage. A subject image incident through the photographic lens system 1 is received by the pixel surface of the image sensor 3, and a charge proportional to the amount of received light is accumulated in each pixel. The accumulated charge of each pixel of the image sensor 3 is output as an analog image signal by the output unit. Note that the image sensor 3 of the first embodiment may be either a charge sequential transfer system (CCD or the like) or an XY address system (CMOS or the like).

  A color filter array in which color filter elements corresponding to red (R), green (G), and blue (B) are arranged is arranged in the effective pixel region on the pixel surface of the image pickup device 3, and the subject image is It is converted into an RGB image signal. As the arrangement of the color filter elements, the R and G filter elements are alternately arranged in the odd columns, the G and B filter elements are alternately arranged in the even columns, and the G filter elements form a checkered pattern as a whole. Etc. are known.

The analog signal processing unit 4 includes a CDS circuit that performs correlated double sampling (CDS), a gain circuit that amplifies the output of the analog image signal, and a color separation circuit. In the analog signal processing unit 4, gain values relating to output of pixels corresponding to RGB colors can be set independently.
The A / D conversion unit 5 converts the analog image signal output from the analog signal processing unit 4 into a digital image signal. The output of the A / D converter 5 is connected to the digital signal processor 6 and the CPU 9.

  The digital signal processor 6 performs processing such as gamma correction and white balance on the digital image signal to generate photographed image data. Note that the captured image data output from the digital signal processing unit 6 is then compression-encoded and recorded on a recording medium, or displayed on a liquid crystal display monitor on the back of the electronic camera (recording medium and liquid crystal). The illustration of the display monitor is omitted).

  The electronic finder unit 7 includes a finder image processing unit 7a, a D / A conversion unit 7b, and a liquid crystal finder 7c. The finder image processing unit 7a generates a finder image based on a digital image signal of a through image captured by the image sensor 3 in the shooting mode. The finder image processing unit 7a can set the gain of the digital image signal of the through image independently for each color of RGB. The finder image generated by the finder image processing unit 7a is displayed on the liquid crystal finder 7c via the D / A conversion unit 7b.

  The auxiliary light source 8 is composed of, for example, LEDs of white, green, red, and the like, and emits auxiliary light for focus detection when photographing a low-luminance subject or the like. FIG. 2 shows the wavelength characteristics of the LED used for the auxiliary light source 8. The white (Type 1), green (Type 2), and red (Type 3) LEDs all have a half-value width (difference in wavelength value at two points that is a half value of the maximum light amount) of 20 to 50 nm, and the illumination light from the LEDs It can be seen that the wavelength width of is quite narrow.

  Although not particularly limited, it is desirable that the LED used for the auxiliary light source 8 is an LED having a wavelength corresponding to the spectral wavelength characteristics of the largest number of color filter elements. For example, in the Bayer color filter as in the present embodiment, the RGB pixels have a ratio of 1: 2: 1. Therefore, the auxiliary light source 8 has an LED having a wavelength corresponding to the spectral wavelength characteristic of the G color filter element. Is preferably used.

The CPU 9 sets modes such as a shooting mode and a playback mode of the electronic camera, controls each part of the electronic camera (control of the drive of the focus motor 2, control of the charge accumulation time of the image sensor 3, and setting of the gain of the analog signal processing unit 4. , And the like, a calculation process necessary for light emission control of the auxiliary light source 8 and the like is executed.
Further, the CPU 9 includes an AE calculation unit 9a, an AWB (auto white balance) calculation unit 9b, and an AF calculation unit 9c. In the AE calculation and the AF calculation in the first embodiment, it is not necessary to use all the image signals of all effective pixel areas of the image sensor 3, and in general, a part of the effective pixel area (for example, the central part of the screen). The calculation is performed using the image signal of the area.

  The AE calculation unit 9 a performs automatic exposure calculation using the digital image signal output from the A / D conversion unit 5. Based on the RGB digital image signal output from the A / D conversion unit 5, the AWB calculation unit 9 b sets the white balance adjustment gain (R gain and B gain) in the digital signal processing unit 6. Further, the AF calculation unit 9 c performs AF calculation based on the digital image signal of each RGB pixel output from the A / D conversion unit 5.

Here, the details of the AF calculation of the AF calculation unit 9c will be described in detail. The AF calculation unit 9c performs the AF calculation by a contrast detection method using the principle that “the degree of image blur and the contrast are correlated and the contrast of the image is maximized at the time of focusing”.
Specifically, the AF calculation unit 9c extracts a high-frequency component of a predetermined band from the output of the focus detection area provided in the image sensor 3 by a bandpass filter, integrates the absolute value of this high-frequency component, and within the focus detection area. The focus evaluation value for the subject image is generated. As shown in FIG. 3, this focus evaluation value becomes the maximum value when the contrast becomes maximum at the in-focus position L0. 3 indicates the lens position of the focusing lens of the photographing lens system 1. In FIG.

  The AF calculation unit 9c moves the focusing lens in a predetermined direction, and compares the focus evaluation values before and after the movement. When the focus evaluation value after movement is large, it is considered that the contrast tends to increase, and the AF calculation unit 9c further moves the focusing lens in the same direction and performs the same calculation. On the other hand, since the contrast is lowered when the focus evaluation value after movement is small, the AF calculation unit 9c performs the same calculation by moving the focusing lens in the reverse direction. The AF calculation unit 9c repeats the above process to search for the peak (focus position) of the focus evaluation value. The above operation is generally referred to as a hill climbing operation.

The operation member 10 includes a mode switch for switching the photographing mode and the playback mode of the electronic camera, a release button, an input button for setting the auxiliary light source 8 on (illuminable) / off (non-illuminated), and the like. ing.
The electronic camera of the first embodiment is configured as described above, and the operation of the shooting mode in the electronic camera of the first embodiment will be described below with reference to the flowchart of FIG.

Step S101: In the photographing mode of the electronic camera, the CPU 9 drives the image sensor 3 at predetermined intervals to generate a through image. The CPU 9 causes the electronic viewfinder unit 7 to display a finder image based on the through image as a moving image while executing AE and AWB calculations based on the image signal of the through image.
Step S102: The CPU 9 determines whether or not the release button is half-pressed by the user. When the release button is half pressed (YES side), the CPU 9 proceeds to step S103, and when there is no input to the release button (NO side), the CPU 9 returns to step S101 and waits for the release button to be half pressed.

Step S103: The CPU 9 determines whether or not the luminance value of the subject detected by the AE calculation unit 9a is equal to or less than a predetermined threshold value. When the luminance value is equal to or smaller than the threshold value (YES side), the CPU 9 proceeds to step S104, and when the luminance value is larger than the threshold value (NO side), the CPU 9 proceeds to step S110.
Step S104: The CPU 9 determines whether or not the auxiliary light source 8 is set to enable illumination during AF. When the auxiliary light source 8 is set to enable illumination (YES side), the CPU 9 proceeds to step S105, and when the auxiliary light source 8 is set to disable illumination (NO side), the CPU 9 proceeds to step S110.

  Step S105: The CPU 9 increases the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light of the auxiliary light source 8 relative to the gain related to the output of the other pixels with respect to the gain setting of the analog signal processing unit 4. Change as follows. As described above, the CPU 9 changes the gain setting of the analog signal processing unit 4 in order to further improve the focus position detection accuracy of the low-luminance subject.

Specifically, for example, when the wavelength of the illumination light of the auxiliary light source 8 falls within the spectral wavelength band of the G pixel, the CPU 9 (a) a process of setting only the gain related to the output of the G pixel high, (b) One of the processes for reducing the gain related to the output of the R and B pixels and (c) the processes (a) and (b) above is executed.
In the first embodiment, the LED of the auxiliary light source 8 is irradiated when the in-focus position of the low-luminance subject is detected. When the auxiliary light source 8 is irradiated, the contrast of the subject is most reflected in the image signal of the color corresponding to the wavelength of the illumination light of the LED. Further, as shown in FIG. 5, the spectral wavelength characteristics of RGB of a general color filter cover a sufficiently wide wavelength band with respect to the half width of the wavelength of the LED of the auxiliary light source 8 (see FIG. 2). I understand.

From this, for example, when the wavelength of the illumination light of the LED falls within the spectral wavelength band of the G pixel, the signal component related to the contrast of the subject increases if at least the gain related to the output of the G pixel is amplified In addition, the detection accuracy of the in-focus position can be further improved. The gain related to the output of the G pixel in step S105 is amplified for the above reason.
On the other hand, in the above example, the output of the R and B pixels has few signal components related to the contrast of the subject image due to the spectral wavelength characteristics, but contains a relatively large amount of noise components in the image signal. Therefore, if the gains of all the RGB pixels are uniformly amplified, the noise component is also amplified, and the focus position detection accuracy of the low-luminance subject may be lowered due to the occurrence of the pseudo peak of the focus evaluation value. Therefore, in the above example, it is preferable not to amplify the gain related to the output of the R and B pixels.

Rather, in the above example, when the gain relating to the output of the R and B pixels is lowered, the generation of the pseudo peak of the focus evaluation value is suppressed, and the focus position detection accuracy of the low-luminance subject is improved. The reason why the gain relating to the output of the R and B pixels is lowered in step S105 is as described above.
In the present invention, the color that relatively increases the gain is determined by the relationship between the wavelength of the illumination light of the auxiliary light source 8 and the spectral wavelength characteristics of the color filter, the optical low-pass filter, and the infrared cut filter. That is, when the wavelength of the illumination light of the auxiliary light source 8 falls within the spectral wavelength band of the R (or B) pixel, the CPU 9 relatively increases the gain related to the output of the R (or B) pixel. For example, when the wavelength of the illumination light of the auxiliary light source 8 extends over the spectral wavelength bands of the R and G pixels, the CPU 9 relatively increases the gain related to the output of the R and G pixels.

  Step S106: The CPU 9 changes the RGB gain setting of the finder image processing unit 7a so that the gain change in the analog signal processing unit 4 can be offset. For example, the CPU 9 sets the RGB gain setting values of the finder image processing unit 7a based on the difference between the gain setting values before and after the change of the analog signal processing unit 4. This is to display an image relatively close to the normal gain setting state on the liquid crystal finder 7c even when special gain amplification (S105) is performed on the image signal when the auxiliary light source 8 is illuminated. Done.

Step S107: The CPU 9 illuminates the subject by causing the auxiliary light source 8 to emit light for detecting the in-focus position. Note that the processing from step S105 to S107 is performed almost simultaneously.
Step S108: The AF calculation unit 9c of the CPU 9 calculates a focus evaluation value based on the RGB image signal whose gain has been adjusted by the analog signal processing unit 4, and detects the in-focus position of the focus lens by a hill-climbing operation.

Step S109: The CPU 9 stops the light emission of the auxiliary light source 8 simultaneously with the completion of detection of the focus position of the focus lens (or the elapse of a predetermined time), and the gain setting of the analog signal processing unit 4 and the finder image processing unit 7a (S105, S106) is restored.
Step S110: In this case, since the luminance value of the subject is sufficiently high or the user does not want to use the auxiliary light source 8, the CPU 9 sets the light emission of the auxiliary light source 8 and the gain setting of the analog signal processing unit 4 to the RGB color. The focus position is detected without changing each time. That is, the AF calculation unit 9c of the CPU 9 calculates the focus evaluation value based on the image signal with the gain setting of the normal analog signal processing unit 4, and detects the focus position of the focus lens by the hill climbing operation.

Step S111: The CPU 9 determines whether or not the release button has been fully pressed (released) by the user. When the release is made (YES side), the CPU 9 proceeds to step S112, and when there is no input to the release button (NO side), the CPU 9 waits for the user release.
Step S112: The CPU 9 drives the image sensor 3 to shoot a subject image. It should be noted that automatic exposure condition setting and white balance gain setting at the time of photographing are performed at least other than when the auxiliary light source emits light. Then, the analog signal processing unit 4 and the digital signal processing unit 6 perform a series of image processing on the image signal of the captured image to generate captured image data. Thereafter, the CPU 9 proceeds to step S101 and repeats the series of operations described above until the photographing mode is canceled.

In the electronic camera according to the first embodiment, the auxiliary light is emitted when detecting the in-focus position, and the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light is relatively increased. For this reason, the detection accuracy of the in-focus position with respect to the dark subject is remarkably improved by increasing the signal component related to the contrast of the subject or reducing the noise component in the image signal.
In the electronic camera of the first embodiment, even when special gain adjustment is performed during auxiliary light illumination, an image that is relatively close to the normal gain setting state is displayed as a moving image on the liquid crystal finder. The visibility of the viewfinder during auxiliary light illumination can be kept relatively good.

(Description of Second Embodiment)
FIG. 6 is a flowchart showing the operation of the photographing mode in the electronic camera of the second embodiment (corresponding to the electronic camera of claims 2 to 4). The number of each step in FIG. 6 substantially corresponds to the number of each step in FIG. 4, and operations other than steps S205 and S208 are the same as those in FIG. In the following embodiment, the same reference numerals are given to the components corresponding to those of the first embodiment shown in FIG.

Step S205: The CPU 9 changes the gain setting of the analog signal processing unit 4 so that the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light of the auxiliary light source 8 is higher than the gain related to the output of the other pixels. To do.
Specifically, for example, when the wavelength of the illumination light of the auxiliary light source 8 falls within the spectral wavelength band of the G pixel, the CPU 9 executes a process of setting only the gain related to the output of the G pixel high. In the above example, if the gain related to the output of the G pixel is amplified, the signal component related to the contrast of the subject increases, so that the detection accuracy of the in-focus position is further improved.

  Step S208: The AF calculation unit 9c of the CPU 9 performs the AF calculation based only on the image signal corresponding to the color including the wavelength of the illumination light. For example, when the wavelength of the illumination light of the auxiliary light source 8 falls within the spectral wavelength band of the G pixel, the AF calculation unit 9c calculates the focus evaluation value based only on the G image signal, and the hill climbing operation of the focus lens The focus position is detected. In the above example, since the output of the R and B pixels contains a relatively large amount of noise components, the use of only the G image signal for the AF calculation suppresses the occurrence of a pseudo peak in the focus evaluation value.

In the second embodiment, the auxiliary light is emitted when detecting the in-focus position, and the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light is relatively increased. Therefore, as in the first embodiment. The effect of can be obtained.
(Description of the third embodiment)
FIG. 7 is a flowchart showing the operation of the photographing mode in the electronic camera of the third embodiment (corresponding to the electronic camera of claims 1 and 5). The number of each step in FIG. 7 substantially corresponds to the number of each step in FIG. 4, and operations other than steps S306, S307, and S309 are the same as those in FIG.

Step S306: The CPU 9 illuminates the subject by causing the auxiliary light source 8 to emit light for detecting the in-focus position.
Step S307: The finder image processing unit 7a continuously outputs the finder image generated immediately before the auxiliary light source 8 emits light to the liquid crystal finder 7c when the auxiliary light source 8 starts to emit light. Accordingly, a still image of a finder image generated immediately before the auxiliary light source 8 emits light is displayed on the liquid crystal finder 7c during auxiliary light illumination in the third embodiment.

  Step S309: The CPU 9 stops the light emission of the auxiliary light source 8 simultaneously with the completion of detection of the focus position of the focus lens (or the elapse of a predetermined time). Then, the CPU 9 restores the gain setting (S305) of the analog signal processing unit 4, cancels the still image display output (S307) of the finder image processing unit 7a, and displays a moving image based on the through image of the finder image processing unit 7a. Resume output.

In the third embodiment, since the image generated immediately before the auxiliary light emission at the time of auxiliary light illumination is displayed as a still image on the liquid crystal finder, the gain setting of the finder image processing unit 7a is changed as in step S106 described above. The processing to perform becomes unnecessary.
(Correspondence between Claims and Embodiments)
Here, the correspondence between the claims and the embodiment is shown. Note that the correspondence shown below is an interpretation given for reference only, and does not limit the technical scope of the present invention.

The “photographing optical system” corresponds to the photographing lens system 1. The imaging element 3 corresponds to “imaging element”. The AF calculation unit 9c corresponds to the “focus position detection unit”. The auxiliary light source 8 corresponds to “auxiliary light source”. The analog signal processing unit 4 corresponds to the “gain adjustment unit”. The electronic finder unit 7 corresponds to the “electronic finder unit”.
(Supplementary items of the embodiment)
As mentioned above, although this invention has been demonstrated by said embodiment, the technical scope of this invention is not limited to the said embodiment.

In the above embodiment, the example of the electronic camera of the electronic viewfinder has been described, but the present invention can of course be applied to the electronic camera of the optical viewfinder.
In the above embodiment, a moving image or a still image of a finder image may be displayed on a portion other than the finder portion (for example, a liquid crystal display monitor on the back of the camera). In the electronic camera of the second embodiment, an image generated immediately before the auxiliary light emission may be displayed as a still image on the liquid crystal finder as in the third embodiment.

In the above embodiment, the analog signal processing unit performs gain adjustment that relatively increases the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light in the AF calculation, but the digital signal processing unit Gain adjustment may be performed.
The color filter of the present invention is not limited to the Bayer array, and other known color filters may be applied. Further, the present invention can be similarly applied to an electronic camera of a complementary color filter having, for example, cyan (Cy), magenta (Mg), and yellow (Y) filter elements.

  The present invention can be applied to a contrast detection type electronic camera that performs autofocus using auxiliary light.

Block diagram of the electronic camera of the first embodiment The figure which shows the wavelength characteristic of LED which is used for the auxiliary light source Diagram showing correlation between focus evaluation value and lens position in contrast detection method Flowchart showing the operation of the shooting mode in the electronic camera of the first embodiment. The figure which shows the spectral wavelength characteristic of the primary color system color filter of the image sensor Flowchart showing the operation of the shooting mode in the electronic camera of the second embodiment Flowchart showing the operation of the shooting mode in the electronic camera of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens system 2 Focus motor 3 Imaging element 4 Analog signal processing part 5 A / D conversion part 6 Digital signal processing part 7 Electronic finder part 7a Finder image processing part 7b D / A conversion part 7c Liquid crystal finder 8 Auxiliary light source 9 CPU
9a AE calculation unit 9b AWB calculation unit 9c AF calculation unit 10 Operation member

Claims (5)

An image sensor that includes a color filter composed of a plurality of color filter elements corresponding to each pixel, and generates an image signal by photoelectrically converting a subject image by a photographing optical system;
A focus position detection unit that calculates a focus evaluation value of the subject image based on the image signal, and detects a position of the photographing optical system that maximizes the focus evaluation value;
An auxiliary light source that illuminates the subject during the detection operation by the in-focus position detection unit;
When the subject is illuminated by the auxiliary light source during the detection operation by the in-focus position detection unit, the gain related to the output of the pixel corresponding to the color including the wavelength of the illumination light by the auxiliary light source is related to the output of the other pixels. An electronic camera comprising: a gain adjusting unit that is relatively increased with respect to the gain. An image sensor that includes a color filter composed of a plurality of color filter elements corresponding to each pixel, and generates an image signal by photoelectrically converting a subject image by the imaging optical system;
An auxiliary light source that illuminates the subject;
When the subject is illuminated by the auxiliary light source, the focus evaluation value of the subject image is calculated based only on the image signal corresponding to the color including the wavelength of illumination light from the auxiliary light source, and the focus evaluation value is the maximum. And an in-focus position detector that detects the position of the photographing optical system as an in-focus position.   In the detection operation by the in-focus position detection unit, a gain adjustment unit that further increases a gain related to an output of a pixel corresponding to a color including a wavelength of illumination light by the auxiliary light source with respect to a gain related to an output of another pixel. The electronic camera according to claim 2. An electronic viewfinder that displays an image based on the image signal;
When the auxiliary light source emits light, the electronic viewfinder unit adjusts the gain of the image signal so as to cancel the gain change of the image signal in the gain adjustment unit, and generates the image. The electronic camera according to claim 1 or 3. An electronic viewfinder that displays an image based on the image signal;
4. The electronic camera according to claim 1, wherein, when the auxiliary light source emits light, the electronic viewfinder unit displays the image generated immediately before the auxiliary light source emits light for a predetermined time.

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