JP2000131597A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make generable proper image signals for focusing detection by eliminating signal level differences among image data obtained by pupil division by performing correction control so that image signals in different areas generated on the basis of an electric signal converted by a solid image pickup element have nearly equal signal levels. SOLUTION: A signal level judging circuit 28 compares right and left AF image signal levels so that the image signal levels become nearly equal to each other and a system controller 29 calculates a correction value by using their level difference value. Namely, the correction value for the signal level of the right AF image signal is obtained on the basis of the signal level of the left AF image signal and the right AF image data stored temporarily in a memory 20 are corrected with the correction value and supplied to a phase AF circuit 26, which nearly equalizes the right and left AF image signal levels to each other. The phase difference is detected on the basis of the corrected right and left AF image signals of the phase AF circuit 26 to calculate the driving feed-out quantity of a focus lens 15 to drive and control to its optimum focus position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera for detecting a focus position from a pupil-divided subject light beam and controlling the focus of an image taking optical unit. An electronic camera that illuminates a subject with auxiliary illumination light or strobe light to enable focus adjustment.

[0002]

2. Description of the Related Art As a main automatic focusing method in an electronic camera, a pupil splitting device built in a photographic optical system is used. A phase difference detection method is employed in which the phase difference of the image signal of the divided photographing subject light, which has been converted and generated based on the photoelectrically converted electric charges, is detected and the focus lens position of the photographing optical system is adjusted and controlled. ing.

[0003] Various methods are used as a subject light dividing method of the pupil dividing device. The aperture / pupil dividing device described in Japanese Patent Application No. 10-213351 filed by the present applicant has been downsized. The best.

[0004] An aperture / pupil division apparatus described in Japanese Patent Application No. 10-212351 will be described with reference to FIG.

[0005] Two blades 4 on the left and right sides are arranged so as to cover a front open hole 41 in which a focus lens of a photographing optical system is disposed.
2, 43 are arranged. The blades 42 and 43 are rotatably supported by the rotating shafts 42a and 43a. These blades 42, 43 have cam holes 42b, 4 formed of elongated holes.
3b is formed, and a driving pin 44 is inserted through the cam holes 42b and 43b in common. The drive pin 44 is driven in a vertical direction in the figure by a drive actuator of a diaphragm / pupil division device (not shown), and a drive force is applied to the cam holes 42b and 43b by the drive pin 44. Transmitted to the blade 4
2, 43 rotate as described later. Further, the blades 42 and 43 have a configuration in which pupil openings 42c and 43c are formed at the edges away from the open hole 41.

An aperture / pupil splitting device having such a configuration is
The following rotation operation is performed.

FIG. 3A shows an open aperture state in which the blades 42 and 43 are opened from the open hole 41.
In this state, the drive pin 44 is located at the uppermost position in the drawing, and the blades 42 and 43 open left and right in the drawing to prevent the photographing light beam from passing through the opening hole 41. Has become.

[0008] From the open aperture state, the drive pin 44
Are moved downward in the figure, the left and right blades 42, 43
Moves in a direction to increase the overlapping portion of each other, and FIG.
As shown in (b), a part of the open hole 41 is shielded by the left and right blades 42 and 43, and a small aperture state is obtained in which the photographic light beam passing through the open hole 41 is stopped down.

When the driving pin 44 is further moved from the small aperture state in a direction in which the overlapping portion of the left and right blades 42, 43 is enlarged, as shown in FIG. The aperture is completely closed by the blades 42 and 43, and the aperture is in a closed state where the photographic light beam passing through the open hole 41 is shielded.

When the drive pin 44 is further moved downward from the aperture closed state, the left and right blades 42, 43
3 is moved in a direction to further increase the superimposed portion of FIG.
As shown in (d), only the pupil opening 42c of the left wing 42 enters the opening 41, and the left automatic focus opening (hereinafter, left A) through which the photographic light beam passes through the pupil opening 42c.
F opening).

From the left AF opening state, the driving pin 4
4 is moved to the lowermost position in the figure,
2 and 43 maximize the overlapping portion with each other, and as shown in FIG. 3E, the pupil opening 43c of the right wing 43 is
1 and the pupil opening 42c of the left wing 42
Is closed by the right blade 43, and enters a right automatic focus opening (hereinafter referred to as a right AF opening) in which a photographing light beam passes through the pupil opening 43c of the right blade 43.

That is, by changing the opening amount of the opening hole 41 in the small aperture state shown in FIG. 3B from the open aperture state shown in FIG. 3A to the aperture closed state shown in FIG. 3C, The amount of luminous flux incident on the solid-state imaging device (not shown) from the photographic optical system is adjusted. Further, a left image signal generated based on a photographing light beam incident on the solid-state imaging device in the left AF opening state in FIG. 3D and an incident on the solid-state imaging device in the right AF opening state in FIG. A phase difference from a right image signal generated based on the obtained photographing light beam is detected to adjust and control a focus lens position of the photographing optical system.

Next, using the aperture / pupil division device,
A method of generating a focus lens position adjustment control signal of the photographing optical system will be described with reference to FIG.

The VD shown in FIG. 4 is a vertical drive signal of the solid-state image sensor, which sets an object light exposure time which is an image forming time of the object light incident on the solid-state image sensor, and a photoelectric conversion by the solid-state image sensor. It is used as a reference for control of read transfer timing of the read charge and for a control signal of various image signal generation circuits for generating an image signal based on the charge read and transferred from the solid-state imaging device.

When a subject light photographed by the photographing optical system is imaged on the solid-state image pickup device at the time of photographing the object with an electronic camera, the accurately focused object light without a focus shift is imaged on the solid-state image pickup device. Need to be done. For this reason,
When the automatic focus adjustment mode provided in the electronic camera is selected and input, the pupil division device is driven based on the first rising edge of the VD signal VD1, and FIG.
In the left AF opening state shown in (d), the subject light that has passed through the pupil splitting device in the left AF opening state is incident on the solid-state imaging device (hereinafter, referred to as a CCD) and exposes the CCD for a predetermined time. .

On the basis of the next rising edge of the VD signal VD2, the pupil splitting device shown in FIG.
The subject light that has been driven into the F opening state and passed through the pupil splitting device in the right AF opening state is incident on the CCD, and
The CD is exposed for a predetermined time. Further, the VD signal VD2
The left image charge in the left AF opening state obtained by exposing and photoelectrically converting the CCD with reference to the rising edge of is read and transferred, output to the various image signal generation circuits, and temporarily stored in a predetermined circuit.

Next, based on the rising edge of the VD signal VD3, the pupil splitting device is driven to open the aperture stop shown in FIG. 3 (a) and to open the right AF aperture photoelectrically converted by the CCD. The right image charges photoelectrically converted in the above are read and transferred, and output to the various image signal generation circuits. The various image signal generation circuits generate image signals based on the charges of the left image and the right image read and transferred from the CCD, and detect a phase difference detected by a phase difference detection circuit based on the generated left and right image signals. Using a calculation formula stored in advance in a system controller formed by a microcomputer or the like based on a, a lens extension amount for adjusting the position of the focus lens is calculated, and the imaging optical system of the imaging optical system is calculated via a focus actuator. Automatic focusing control (hereinafter referred to as AF control) for performing position adjustment control of the focus lens is performed.

In an electronic camera using such focus detection by pupil division, the phase shift amount of each image captured in a different pupil region is compared, and each region is calculated in order to calculate the focus shift amount. If the brightness of the image captured in step is insufficient, accurate focusing adjustment cannot be performed. In particular, in pupil division, since the aperture diameter of the pupil opening is reduced and a light beam of a small aperture is used, the influence is large when the subject light is darker than a predetermined value.

When the diameter of the pupil opening is increased in order to obtain a sufficient amount of light by one CCD exposure on the left and right, the difference between the pupil-divided left and right images is reduced. There is a problem that a proper focusing cannot be performed.

For this purpose, the conventional electronic camera is provided with an auxiliary light or a strobe light emitting device for illuminating the subject, and illuminates the subject from each of the auxiliary light and the strobe light emitting device in each area divided by the aperture / pupil splitting device. Thus, the subject light having the luminance value required for the focus adjustment control is obtained.

[0021]

A conventional electronic camera detects a phase difference based on an image signal obtained from pupil-divided subject light, generates a focus adjustment control signal, and generates a focus lens position of a photographic lens system. Although adjustment is performed, when the subject light is equal to or less than a predetermined luminance value, the pupil-divided area is obtained by illuminating the subject with an auxiliary lighting device or a strobe light emitting device for subject illumination provided in the electronic camera. The control signal for focus adjustment is generated based on the image signal obtained by photographing each subject, but the first light emission and the next light emission of the auxiliary light device or the strobe light emitting device are different from the warm-up time. Due to a difference or a decrease in the charge voltage of the capacitor, a difference occurs between the subject when the first region of the pupil-divided region is photographed and the amount of illumination applied to the subject when the next region is photographed, Pupil Suitable focusing adjustment control signal generated in the difference in the signal level of the imaging-obtained image signal had been no problem obtained.

According to the present invention, when subject light is illuminated with an auxiliary light or a strobe light with a predetermined luminance value or less, the signal level difference of the image signal obtained by the pupil division can be eliminated to obtain an appropriate focus detection. An object of the present invention is to provide an electronic camera that generates an image signal.

[0023]

Means for Solving the Problems A first invention of the present invention is:
A photographing optical unit including a plurality of lenses including a focus lens, a pupil dividing unit that divides a photographing light beam of the photographing optical unit into two regions in time series, and forms an image of subject light photographed by the photographing optical unit. A solid-state imaging device that converts the signals into electric signals, a light-emitting unit that irradiates the subject with illumination light for each of the different regions that are time-series divided by the pupil dividing unit, and an electric signal that is converted by the solid-state imaging device. An image signal generating unit that generates an image signal; and a focus position control signal that is divided by the pupil dividing unit and generates a focus position control signal based on image signals of different regions generated by the solid-state imaging device and the image signal generating unit. A focus detection means; and a focus drive control means for controlling a position of a focus lens of the photographing optical means based on a focus position control signal generated by the focus detection means. The means controls illumination of a subject by irradiating illumination light from the light emitting means for each area divided by the pupil dividing means, and image signals of different areas generated based on the electric signals converted by the solid-state imaging device. Is an electronic camera that performs correction control so that the signal levels of the signals are substantially the same.

According to a second aspect of the present invention, there is provided a photographing optical unit comprising a plurality of lenses including a focus lens, a pupil dividing unit for dividing a photographing light beam of the photographing optical unit into two regions in time series, A solid-state imaging device that forms an image of a subject light photographed by the photographing optical unit and converts the light into an electric signal; a strobe light emitting unit that emits illumination light to the subject; and controls light emission of the illumination light emitted from the strobe light emitting unit. Strobe light emission control means, image signal generation means for generating an image signal based on the electric signal converted by the solid-state imaging device, and division by the pupil division means, and generation by the solid-state imaging device and the image signal generation means Focus detection means for generating a focus position control signal based on the image signals of the different areas obtained by the focus detection means, and a focus position control signal generated by the focus detection means. ; And a focus driving control means for controlling the position of Surenzu, the image signal generating means,
The light emission control of the illumination light from the strobe light emitting means is performed through the strobe light emission control means for each of the areas divided by the pupil dividing means, and the different areas generated based on the electric signals converted by the solid-state imaging device are controlled. This is an electronic camera that performs correction control so that the signal levels of image signals are substantially the same.

According to a second aspect of the present invention, the strobe light emission control means includes a first photographing method in which the illumination time of the illumination light emitted from the strobe light emission means in synchronization with the pupil division means is divided and photographed by the pupil division means. This is an electronic camera in which the emission irradiation time of the next photographing area is set longer than that of the area.

In the second invention, the strobe light emission control means detects a drop in the drive power supply voltage at the time of the first light emission and at the time of the next light emission of the strobe light emission means. An electronic camera for selecting a next light emission irradiation time after the first light emission of the strobe light emitting means.

Further, in the second invention, the strobe light emission control means detects a drive power supply voltage value at the time of the first light emission and the next light emission of the strobe light emission means, and detects the strobe light from the drive power supply voltage value. It is an electronic camera for selecting the next light emission irradiation time after the first light emission of the light emitting means.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of an electronic camera according to the present invention.

Reference numeral 11 in the drawing denotes a photographing lens system for taking in light from a subject, and a zoom lens 12 for changing the size of the subject at least, a shutter 13, and a pupil splitting device 14 also serving as an aperture.
And a focus lens 15. In addition,
The aperture / pupil division device 14 performs the configuration and operation described with reference to FIG.

The subject light photographed by the photographing lens system 11 forms an image on the solid-state image sensor 16. The solid-state imaging device (hereinafter, referred to as a CCD) 16 converts the formed subject light into electric charges. The charges converted by the CCD 16 are sequentially read and transferred to the imaging circuit 17 to generate an image signal. The image signal generated by the imaging circuit 17 is A / A
The image data is converted from an analog signal to a digital image signal by the D circuit 18, converted into digital data format image data by the image signal processing circuit 19, and temporarily stored in the memory 20.

The image data stored in the memory 20 is converted into an image reproduction signal by an image display circuit 21 based on an operation input to be described later, and the image of the subject light is reproduced and displayed on an image display section 22. The image display unit 22 uses a liquid crystal display element.

The image data temporarily stored in the memory 20 is compressed by a compression / expansion circuit 23 in response to an operation input, and is written and stored in a removable memory 25 via a memory interface (hereinafter, referred to as a memory I / F) 24. I do. This removable memory 25 is a memory medium formed as an IC card. The image data written and stored in the removable memory 25 is read out via the memory I / F 24, and the image data read out by the compression / expansion circuit 23 is expanded, and the memory 20 and the image display processing circuit 2 are expanded.
1, the image display unit 22 can also reproduce the image of the image data written and stored in the detachable memory 25.

The digital image signal converted by the A / D circuit 18 is supplied to a phase automatic focusing circuit (hereinafter referred to as a phase A
F circuit 26), a hill-climbing automatic focus circuit (hereinafter, hill-climbing AF circuit) 27, and a signal level determination circuit 28. The image data generated by the image processing circuit 19 is supplied to the phase AF circuit 26 and the hill-climbing AF circuit 27. The phase AF circuit 26
Detects a digital image signal generated based on the subject light pupil-divided by the aperture / pupil division device 14 or a phase difference of image data. The hill-climbing AF circuit 27 detects a digital image signal generated based on subject light that has not been pupil-divided by the aperture / pupil division device 14 or a high-frequency component of image data. The signal level determination circuit 28
Determines the luminance value of the photographic subject from the signal level of the digital image signal supplied from the A / D circuit 18.
The phase AF circuit 26, the hill climbing AF circuit 27,
The output of the signal level determination circuit 28 is supplied to a system controller (hereinafter, referred to as a syscon) 29 formed by a microcomputer.

The system controller 29 is connected to the phase AF circuit 2
6 and the high-frequency component from the hill-climbing AF circuit 27 to perform focus drive control, which will be described later, and the luminance value from the signal level determination circuit 28 to control the drive of the aperture opening of the aperture and pupil division device 14. At the same time, the operation of the image processing circuit 19 is controlled. Further, the CC
D16 and a timing generation circuit (hereinafter, referred to as a TG circuit) 32 for controlling the operation of the imaging circuit 17 are also controlled.

An EEPROM 30 is added to the system controller 29, and stores various reference data necessary for operating or operating the electronic camera and processing procedures of the system controller 29 according to the operation.

Further, the system controller 29 includes various photographing modes of the electronic camera, for example, selection of phase AF or hill-climbing AF at the time of focus adjustment, display of the image data temporarily stored in the memory 20 on the image display section 22, And writing and recording in the detachable memory 25, or selection of reproduction display of the image data stored in the detachable memory 25 on the image display unit 22, selection of the zoom lens magnification, selection of strobe operation, and release for shooting Each operation unit 31 for inputting various operations such as input is connected.

From the system controller 29, a zoom motor 33b is driven via a zoom circuit 33a for driving a zoom lens of the photographing lens system 11, and an actuator 34b is driven via a shutter circuit 34a for driving the shutter 13.
A driving circuit 3 for driving the aperture / pupil dividing device 14
A focus motor driving circuit 36a for driving the focus lens 15
And the focus motor 36b is connected to each other. The system controller 29 includes a strobe circuit 37a.
And strobe condenser 37b and strobe light emitting part 37
The series circuit c is connected to an automatic focus auxiliary light (hereinafter, referred to as AF auxiliary light) 38, and a charging voltage value of the strobe capacitor 37 b is supplied to the syscon 29.

In the electronic camera having such a configuration, a phase difference detection method using a pupil-divided photographed image is selectively input from each of the operation units 31 to adjust the position of the focus lens of the photographing lens system 11. The strobe light emitting portion 37c when the subject light captured by the system 11 and formed on the CCD 16 has a brightness value equal to or less than a predetermined value and is dark.
Alternatively, a focusing operation based on subject light irradiated with illumination light emitted from the AF auxiliary light 38 will be described with reference to FIG.

Generally, when focusing is performed, a focusing mode is input while a release switch (not shown), which is a part of each of the operation sections 31, is half-pressed. In addition, the light emission of the flash light emitting portion 37c or the AF auxiliary light 38 is performed by inputting a light emission mode from each of the operation portions 31 or during the focus mode operation based on the luminance of the subject light.
c or a method of controlling the emission of the AF auxiliary light 38.

Here, in a state where the mode for irradiating the auxiliary illumination to the subject at the time of the focusing operation is input from each of the operation units 31, the focus position adjustment of the focus lens 15 of the photographing lens system 11 and the strobe light emission are performed. The light emission control of the unit 37c will be described as an example.

Each of the operation units 31 to the strobe light emitting unit 37
When the light emission mode and the focusing mode are input, the system controller 29 controls the start of the supply of the light emission power from the operation power supply (not shown) to the strobe capacitor 37b via the strobe circuit 37a, and also outputs the VD signal. VD1
A drive control signal is supplied to the drive circuit 35a based on the rising edge of the drive circuit 35a, and the driving force from the drive circuit 35a drives the actuator 35b to bring the aperture / pupil division device 14 into the left AF opening state. . On the other hand, the system controller 29 controls the TG circuit 32 to generate a timing signal based on the VD signal, and supplies the timing signal to the CCD 16 and the imaging circuit 17. Said C
The CD 16 sets the timing at which the drive of the pupil splitting device 14 is completed as the exposure start, sets the falling edge of the VD signal VD1 as the exposure end, and uses the subject light incident in the left AF opening state of the aperture and pupil splitting device 14 as the exposure light. Exposure (hereinafter referred to as left AF exposure) is performed. At this time, the system controller 29 supplies a light emission signal of the strobe light emitting section 37c to the strobe circuit 37a, and the strobe light emitting section 37c is turned on for a predetermined time by the strobe light emitting power supply precharged to the strobe capacitor 37b. The light is emitted at t1.

That is, at the time of the left AF exposure of the CCD 16, the subject light illuminated by the light emission of the strobe light emitting portion 37c for the predetermined time t1 is exposed.

At the next rising edge of VD2 of the VD signal, the pupil splitting device 14 is driven to make the right AF opening state, and the CCD 16 is exposed by the subject light incident in the right AF opening state. (Hereafter, right A
F exposure). At this time, the syscon 29 is
A strobe light emitting unit 37 is provided for the strobe circuit 37a.
c, and a strobe capacitor 3
The strobe light emitting unit 37c emits light for a predetermined time period t2 by a strobe light emitting power supply precharged to 7b.

That is, in the right AF exposure of the CCD 16, the subject light illuminated by the light emission of the strobe light emitting portion 37c for the predetermined time t2 is exposed. The relationship between the light emission times t1 and t2 of the strobe light emitting section 37c is as follows.
It is assumed that t1 = t2.

Further, based on the VD2 of the VD signal, the charge of the left AF exposure of the CCD 16 is transferred and output, and is converted into a digital image signal by the imaging circuit 17 and the A / D circuit 18, and is converted into a digital image signal. Is supplied to the signal level determination circuit 28. The left AF digital image signal supplied to the phase AF circuit 26 is
Is temporarily stored in a memory function for one image signal built in the.

Next, at the rising edge of VD3 of the VD signal, the aperture / pupil division device 14 is driven to open the aperture stop state, and the right AF exposure charge of the CCD 16 is read out, transferred and output. And the right AF digital image signal through the A / D circuit 18 to the phase A
The signal is supplied to an F circuit 26 and the signal level determination circuit 28.
Further, the right AF digital image signal is converted into image data by an image signal processing circuit 19 and is temporarily stored in the memory 20 (denoted as right AF (W) in the figure).

Next, in VD4 of the VD signal, the signal level of the left and right AF digital image signals is determined by the signal level determination circuit 28, and the difference between the signal levels is supplied to the system controller 29 to correct the correction value data. And reads out the right AF image data temporarily stored in the memory 20 (denoted as right AF (R) in the figure), and corrects the right AF image data with the correction value generated by the system controller 29. Then, it is supplied to the phase AF circuit 26.

That is, the amount of strobe light from the strobe light emitting portion 37c projected on the subject at the time of the left AF opening of VD1 of the VD signal and the strobe light projected on the subject at the time of the right AF opening of VD2 of the VD signal. The amount of strobe light from the light emitting unit 37c is determined by the applied voltage supplied from the strobe capacitor 37b to the strobe light emitting unit 37c.
At the time of F, the applied voltage decreases. At the time of the left AF and at the time of the right AF, there is a difference in the amount of light irradiated to the subject, and there is a difference in the level of the left and right AF image signals exposed and generated by the CCD 16. An error occurs in the phase difference detection detected in the step (1). For this reason, the signal level determination circuit 28 compares the left and right AF image signal levels so that the left and right AF image signal levels become substantially the same, and the system controller 29 uses the level difference value between the left and right AF image signals to correct the correction value. Is calculated. That is, a correction value of the signal level of the right AF image signal is obtained based on the signal level of the left AF image signal, and the right AF image data temporarily stored in the memory 20 is corrected using the correction value, and the phase AF circuit 26, the phase AF circuit 26 makes the left and right AF image signal levels substantially the same.

Next, at VD5 of the VD signal, the phase difference is detected based on the corrected left and right AF image signals of the phase AF circuit 26, and the system controller 29 drives the focus lens 15 of the photographing lens system 11 to drive out. Is calculated and supplied to the focus motor drive circuit 36a to control the drive of the focus motor 36b, thereby controlling the drive of the focus lens 15 to the optimum focus position.

Thus, the left and right AF images divided and captured by the aperture / pupil division device 14 formed on the CCD 16 due to the difference in the amount of strobe light emitted from the strobe light emitting portion 37c between the first light emission and the next light emission. By correcting the signal level difference, the levels of the image signals to be compared by the phase AF circuit 26 are substantially in the same state, and the optimum focus adjustment control can be performed based on the detected phase difference.

The AF provided in the electronic camera
As the auxiliary light 38, a light source such as an LED or a lamp is used. However, these light sources are supplied with lighting power and require a long time to emit a stable amount of light. A signal level difference occurs between the left and right AF image signals obtained by exposing the subject light to the CCD 16. For this reason, in irradiating the subject at the time of focusing using the AF auxiliary light 38 instead of irradiating the subject from the strobe light emitting section 37c, the determination and correction of the left and right AF image signal levels are similarly performed. The signal level is made substantially the same, and the phase AF
Based on the phase difference detected by the circuit 26, the system controller 29 calculates the amount of extension of the focus lens 15 by the system controller 29.

Next, another embodiment of the present invention will be described. In another embodiment, the aperture / pupil splitting device 1 is used.
As a method for solving the difference in the left and right AF image signal levels caused by the difference in the amount of light emitted from the strobe light emitting portion 37c to the subject in the left and right AF opening state where the pupil is divided at 4, the strobe light emitting portion 37c has a left AF position. By setting the relationship between the first light emission time t1 and the second light emission time t2 at the time of the right AF to be t1 <t2, the level of the amount of light emitted to the subject is equalized.

In general, light emission of the strobe light emitting portion 37c is performed by a voltage charged in the strobe capacitor 37b. For this reason, the strobe light emitting section 37
The value of the voltage at the time of the first light emission applied to c is equal to the charging voltage value of the flash capacitor 37b.
The voltage value at the time of the second light emission is a voltage value at which the charging voltage of the flash capacitor 37b is reduced. Thereby, the strobe light emitting unit 37c at the time of the first and second light emission is provided.
Causes a difference in the amount of light applied to the subject.

In order to compensate for the decrease in light quantity between the first light emission and the second light emission, the light emission time t2 of the strobe light emitting section 37c at the second light emission is made longer than the first light emission time t1 ( At time t1 <t2), the signal level difference between the left and right AF image signals is eliminated by setting the first and second times the amount of light applied to the subject to be substantially the same.

Specifically, the strobe capacitor 3
7b, and supplies the detected voltage value to the system controller 29. The syscon 29 is provided with the strobe light emitting unit 3 detected by the strobe condens 37b.
A voltage difference between the voltage value before the first light emission of 7c and the voltage value before the second light emission of 7c is obtained. Based on this voltage difference, the voltage difference between the voltage value of the strobe light emitting unit 37c and the first light emission time t1 is 2 The length of the second light emission time t2 is set.

That is, the amount of the strobe light applied to the subject is obtained by the product (v × t) of the voltage v applied to the strobe light emitting portion 37c and the light emission time t. The strobe light emission amount (v2 × t2) at the time of the second light emission is equal to the strobe light irradiation amount (v2 × t2) at the time of the first light emission of the unit 37c. The light emission time t2 is calculated and calculated from the applied voltage v2 in the unit 37c, and the drive control of the strobe circuit 37a is performed based on the calculated time t2. By performing the same amount of strobe light irradiation during the second right AF shooting, the left and right AF
Optimal focus adjustment control of subject photographing with auxiliary lighting with strobe light that makes the signal level of the image signal substantially the same can be performed.

Next, as a modified example of the other embodiment, the EEPROM 3 added to the system controller 29 will be described.
In advance, an emission time table of the strobe light emitting unit 37c corresponding to the charging voltage value of the strobe capacitor 37b is stored in advance at 0, and the EE is set according to the charging voltage value of the strobe capacitor 37b detected by the system controller 29.
The corresponding light emission time is read from the light emission time table of the PROM 30, and the flash circuit 37 is read out based on the corresponding light emission time.
By controlling the first and second light emission times via a, the signal levels of the left and right AF image signals pupil-divided by the aperture / pupil division device 14 can be the same.

As described above, the subject light is captured for each pupil-divided region of the subject, and the focus adjustment control signal generated based on the phase difference of the image signals generated from the captured different regions of the subject light is used. In an electronic camera that performs optimal focus adjustment, the subject light is irradiated with subject illumination light for each of the pupil-divided regions from a focusing auxiliary light source or a strobe light source provided in the electronic camera when the subject light is equal to or less than a predetermined luminance value. A signal level difference between the generated AF image signals in the different areas is detected, and one signal level of the different areas is used as a reference.
After correcting the signal level of the other area to make the image signal levels of both areas substantially the same, it is possible to detect the phase difference between the image signals of both areas to enable optimal focusing adjustment of the focus lens of the photographing lens system, Also, when using the strobe light source, the first strobe light irradiation amount when photographing one of the pupil-divided regions is the same as the second strobe light irradiation amount when photographing another region. In order to achieve this, a calculation is performed from the charging voltage value of the strobe light emitting power supply capacitor at the time of light emission, strobe control is performed so that the second strobe light emission time is longer than the first strobe light emission time, and the pupil division is performed. In addition, the signal levels of the AF image signals in different areas are made the same, so that the optimum focusing position of the photographing lens system can be adjusted.

Although one embodiment of the present invention and another embodiment of the present invention have been described separately, it is also possible to implement each of the embodiments in combination.

That is, the strobe light emission time from the strobe light emitting unit when photographing one area of the different pupil-divided areas and the strobe light emission time from the strobe light emitting unit when photographing the other area are determined by the strobe condenser. And comparing the signal levels of the AF image signals of the objects illuminated with different strobe light emission times from the strobe light emitting unit, based on the charging voltage value of The system controller corrects the image signal level of one area with reference to the image signal level of the other area,
By obtaining the focusing phase difference by equalizing the image signal level difference between the two areas, more optimal focusing adjustment control becomes possible.

[0061]

According to the present invention, when illuminating the subject with an auxiliary light source or a strobe light source to perform pupil division automatic focusing in a time series, the signal level between the time series divided image signals is uniform. This makes it possible to provide an electronic camera capable of easily obtaining optimum focus adjustment control.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an electronic camera according to the present invention.

FIG. 2 is a timing chart illustrating the operation of the present invention.

FIG. 3 is a plan view for explaining the operation of the pupil division device according to the present invention.

FIG. 4 is a timing chart for explaining a problem of a phase difference detection AF used in a conventional pupil division device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Photographing lens system 12 ... Zoom lens 13 ... Shutter 14 ... Aperture / pupil division device 15 ... Focus lens 16 ... Solid-state imaging device 17 ... Imaging circuit 18 ... Analog / Digital conversion circuit 19 ... Image processing circuit 20 ... Memory 21 ... Image Display circuit 22 ... Image display device 23 ... Compression / expansion circuit 24 ... Memory interface 25 ... Removable memory 26 ... Phase difference automatic focus circuit 27 ... Chill climbing automatic focus circuit 28 ... Signal level judgment circuit 29 ... System controller 30 ... EEPROM 31 ... Each operation Unit 32: Timing generator circuit 33a: Zoom circuit 33b: Zoom motor 34a: Shutter circuit 34b: Actuator 35a: Drive circuit 35b: Actuator 36a: Focus motor drive circuit 36b: Focus Motor 37a ... strobe circuit 37b ... flash capacitor 37c ... flash projector 38 ... autofocus auxiliary light

Claims (5)

[Claims] A photographing optical unit comprising a plurality of lenses including a focus lens; a pupil dividing unit for dividing a photographing light beam of the photographing optical unit into two regions in a time series; and a subject photographed by the photographing optical unit. A solid-state imaging device that forms light and converts it into an electric signal; a light emitting unit that irradiates a subject with illumination light for each of different regions that are time-separated by the pupil division unit; and a light-emitting unit that is converted by the solid-state imaging device. Image signal generating means for generating an image signal based on an electric signal, and divided by the pupil dividing means, based on image signals of different regions generated by the solid-state imaging device and the image signal generating means,
Focus detection means for generating a focus position control signal, and focus drive control means for controlling the position of the focus lens of the photographing optical means based on the focus position control signal generated by the focus detection means. The image signal generating means irradiates illumination light from the light emitting means with respect to each area divided by the pupil dividing means to control the illumination of a subject, and generates the image signal based on the electric signal converted by the solid-state imaging device. An electronic camera, wherein the correction control is performed so that the signal levels of the image signals in the different areas become substantially the same. 2. A photographing optical unit comprising a plurality of lenses including a focus lens, a pupil dividing unit for dividing a photographing light beam of the photographing optical unit into two regions in time series, and a subject photographed by the photographing optical unit. A solid-state imaging device that forms an image of light and converts the light into an electric signal; a strobe light emitting unit that emits illumination light to a subject; a strobe light emission control unit that controls emission of illumination light emitted from the strobe light emitting unit; Image signal generating means for generating an image signal based on the electric signal converted by the solid-state imaging device; and dividing by the pupil dividing means, image signals of different regions generated by the solid-state imaging device and the image signal generating means. Based on
Focus detection means for generating a focus position control signal, and focus drive control means for controlling the position of the focus lens of the photographing optical means based on the focus position control signal generated by the focus detection means. The image signal generation unit controls the emission of illumination light from the strobe light emitting unit via the strobe light emission control unit for each area divided by the pupil division unit,
An electronic camera, wherein correction control is performed so that signal levels of image signals in different regions generated based on the electric signals converted by the solid-state imaging device become substantially the same. 3. The strobe light emission control means sets an irradiation time of illumination light emitted from the strobe light emission means in synchronization with the pupil division means as compared with an initial photographing area to be divided and photographed by the pupil division means. 3. The electronic camera according to claim 2, wherein the emission irradiation time of the next photographing area is lengthened. 4. The strobe light emission control means detects a drop in the drive power supply voltage at the time of the first light emission and the next light emission of the strobe light emission means. 3. The electronic camera according to claim 2, wherein a next light emission irradiation time after the light emission is selected. 5. The strobe light emission control means detects a drive power supply voltage value at the time of the first light emission of the strobe light emission means and at the time of the next light emission, and, based on the drive power supply voltage value, after the first light emission of the strobe light emission means. 3. The electronic camera according to claim 2, wherein a light emission irradiation time next to the light emission time is selected.