JP2003140027A - Automatic focusing device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption required for emission of AF fill-in light when irradiating an object with the AF fill-in light in order to improve the contrast of the object. SOLUTION: A photographing lens is moved in a focusing range, and an evaluation value corresponding to the contrast component of the object is collected each time the photographing lens is moved to a prescribed extent, and a movement position giving a peak evaluation value is obtained on the basis of movement positions of the photographing lens and evaluation values obtained for respective movement positions, and the photographing lens is moved to the obtained movement position to perform contrast AF. When the object is irradiated with the AF fill-in light in order to improve the contrast of the subject, the AF fill-in light is not continuously emitted in the period of movement of the photographing lens but is emitted at each time of movement to the prescribed extent of the photographing lens (that is, the AF fill-in light is intermittently emitted (refer to (E) and (G) in Figure 7).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus adjusting device for a camera, and more particularly to a camera which automatically adjusts the lens position of a focus lens (hereinafter referred to as "contrast AF") so as to maximize the contrast of a subject. The present invention relates to an automatic focusing device.

[0002]

2. Description of the Related Art Contrast AF, which has become the mainstream in digital cameras and the like, captures an image while moving a focus lens of the photographic optical system that acts on focus adjustment, extracts high-frequency components from the output image signal, and combines them. An evaluation value for focusing is calculated, and the focus lens is moved to a position where the evaluation value is maximum (where the contrast is maximum) to focus.

However, in contrast AF, when the contrast of the subject is low (when the contrast of the subject is originally low such as a wall or when the contrast is low because the subject is dark), the focus lens is moved over the focus adjustment range. There is a problem that the evaluation value for focusing obtained while moving becomes small as a whole, and the lens position of the focus lens having the maximum evaluation value cannot be accurately obtained.

In view of this, the automatic focusing apparatus disclosed in Japanese Patent Laid-Open No. 2000-121924, when the subject is dark,
The subject is irradiated with auxiliary light (hereinafter referred to as "AF auxiliary light") so that contrast can be obtained from the subject, and the amount of AF auxiliary light is controlled so that the amount of light is particularly appropriate according to the brightness of the object. In this way, power saving is achieved.

[0005]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
The automatic focus adjustment device described in Japanese Patent Application Laid-Open No. 000-121924 prevents the AF auxiliary light from being emitted more than necessary by controlling the light amount of the AF auxiliary light according to the subject brightness. If the AF auxiliary light is emitted during the period of movement over the focus adjustment range, there is a problem that power consumption increases.

The present invention has been made in view of the above circumstances, and reduces the power consumption required for emitting the AF auxiliary light when the object is irradiated with the AF auxiliary light in order to increase the contrast of the object. It is an object of the present invention to provide an automatic focus adjusting device for a camera capable of performing the following.

[0007]

In order to achieve the above object, the invention according to claim 1 is to output the image pickup means each time the image pickup lens is moved over a focus adjustment range and the image pickup lens is moved by a predetermined amount. An evaluation value corresponding to the contrast component of the subject is obtained based on the image signal, and a movement position where the evaluation value reaches a peak is obtained based on the movement position of the photographing lens and the evaluation value obtained for each movement position. In an automatic focus adjusting device for a camera that moves a photographing lens to a determined movement position, an AF auxiliary light emitting unit that emits AF auxiliary light and the A
And a control unit for emitting the AF auxiliary light from the F auxiliary light emitting unit.

That is, in contrast AF, the photographing lens is moved over the focus adjustment range, and an evaluation value corresponding to the contrast component of the subject is collected every time the photographing lens moves by a predetermined amount. The auxiliary light is not emitted continuously, but is emitted every time the photographing lens moves by a predetermined amount (that is, the AF auxiliary light is emitted intermittently). As the emission period of this AF auxiliary light,
It is within the light receiving period in which the image pickup means receives the subject light in order to obtain the image signal.

According to a second aspect of the present invention, there is provided brightness detection means for detecting the brightness of the subject, and the control means is such that the brightness of the subject detected by the brightness detection means is equal to or lower than a predetermined brightness. In this case, the AF auxiliary light emitting means emits the AF auxiliary light.

The control means may stop the AF auxiliary light from the AF auxiliary light emitting means while the photographing lens is moving by a predetermined amount.

As described in claim 4, the AF auxiliary light emitting means is also used as a light emitting means for emitting photographing auxiliary light at the time of stroboscopic photography, and the light emitting means is a light emitting diode, an organic electroluminescence device, and a plasma light emitting device. It is characterized by being constituted by any one of the light emitting elements.

According to a fifth aspect of the present invention, the control means controls the current applied to the light emitting element or the number of elements for selectively emitting light so that the light quantity of the AF auxiliary light is smaller than the light quantity of the photographing auxiliary light. It is characterized by reducing. That is, the light amount of the AF auxiliary light may be the minimum light amount required for the contrast AF (for example, about 30% of the optimum light amount), and thereby the power consumption is further reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an automatic focus adjusting device for a camera according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an external view of a digital camera to which the present invention is applied. On the front of this digital camera 10,
A taking lens 12, a finder window 14, a strobe light emitting section 16, and a light control sensor 17 are provided, and a shutter button 18 and a power switch 20 are provided on the top surface of the camera. A card slot 26 for mounting a memory card 24 is provided on the side surface of the camera opposite to the grip portion 22.

A zoom lens is applied to the taking lens 12, and a CCD image sensor (not shown in FIG. 1, shown as reference numeral 52 in FIG. 3) is arranged behind the taking lens 12. The shutter button 18 is configured in a two-step manner. The contrast AF (AF) and the automatic exposure control (AE) are activated in a "half-press" state where the shutter button 18 is lightly pressed and stopped, and AF and AE are locked, Shooting is performed in a state of "full-press" in which the button is pressed further from "press".

The power switch 20 is also used as a mode switch, and is in an "OFF position" in which the power is turned off.
"Shooting ON position" where the power is turned on in the still image shooting mode,
And "playback ON position" 3 that the power is turned on in playback mode
The position can be switched. It should be noted that, instead of the power switch (hereinafter referred to as a power / mode switch) 20 as in this example, a power switch for turning the power ON / OFF only and a mode switching means such as a mode dial for switching the still image shooting mode and the reproduction mode are provided. It may be provided.

FIG. 2 is a rear view of the digital camera 10. A finder 28, a liquid crystal monitor 30, a zoom switch 32, a multifunctional cross button 34, an AE lock button 36, a menu key 38, an execute key 40 and a cancel key 42 are provided on the back surface of the digital camera 10. The liquid crystal monitor 30 is a display unit that can be used as an electronic viewfinder for confirming the angle of view at the time of shooting, and can display a preview image of a shot image, a reproduced image read from the memory card 24, and the like. Further, selection of a menu using the cross button 34 and setting of various items in each menu are also performed using the display screen of the liquid crystal monitor 30.

The zoom switch 32 is composed of a lever switch that can be operated in the up and down directions. When the switch is operated in the up direction, the zoom switch is moved in the telephoto (TELE) direction, and when it is operated in the down direction, the wide angle (WIDE). ) Move in the zoom direction. The cross button 34 is pressed in one of the upper, lower, left, and right edges so as to be pressed in the corresponding four directions (up, down, left,
The right button can be input, and it is used as an operation button to instruct selection of various setting items on the menu screen and change of setting contents, as well as electronic zoom magnification adjustment and playback frame forwarding / returning. Used as a means to give instructions.

The menu key 38 is used when making a transition from the normal screen in each mode to the menu screen. The execution key 40 is used when confirming the selected content, instructing execution (confirmation) of processing, and the like. The cancel key 42 is used to cancel (cancel) the item selected from the menu or to return to the previous operation state.

The photographer operates the zoom switch 32 to determine the angle of view while confirming the real-time image (through image) displayed on the viewfinder 28 or the liquid crystal monitor 30, and presses the shutter button 18 to perform photographing. .

FIG. 3 is a block diagram showing the internal structure of the digital camera 10. The taking lens 12 is a fixed lens 4
4, a variable power lens 46A, a correction lens 46B, and a focus lens 48, which are four-group inner-focus zoom lenses.

The variable power lens 46A and the correction lens 46B are
A cam mechanism (not shown) regulates the positional relationship between the two, and moves along the optical axis to change the focal length. In addition,
For convenience of description, the variable power optical system including the variable power lens 46A and the correction lens 46B will be referred to as a "zoom lens 46".

The light that has passed through the taking lens 12 has a diaphragm 50.
After the amount of light is adjusted by, the light is incident on a CCD image sensor (hereinafter referred to as CCD) 52. Photosensors are two-dimensionally arranged on the light-receiving surface of the CCD 52, and the subject image formed on the light-receiving surface of the CCD 52 through the taking lens 12 has a signal charge of an amount corresponding to the amount of incident light by each photosensor. Is converted to. The CCD 52 controls the charge storage time (shutter speed) of each photo sensor according to the timing of the shutter gate pulse.
It has a so-called electronic shutter function.

The signal charge accumulated in each photosensor is
The voltage signals (image signals) corresponding to the signal charges are sequentially read out based on the pulses given from the CCD driver 54. The image signal output from the CCD 52 is sent to the analog processing unit 56. The analog processing unit 56 includes a signal processing circuit such as a sampling and holding circuit, a color separation circuit, and a gain adjustment circuit. In the analog processing unit 56, a correlated double sampling (CDS) process and R,
Color separation processing is performed on each of the G and B color signals, and the signal level of each color signal is adjusted (pre-white balance processing).

The signal output from the analog processing unit 56 is converted into a digital signal by the A / D converter 58 and then stored in the memory 60. The timing generator (TG) 62 gives a timing signal to the CCD driver 54, the analog processing section 56 and the A / D converter 58 in accordance with a command from the CPU 64, and each circuit is synchronized by this timing signal. .

The data stored in the memory 60 is transferred to the bus 6
It is sent to the signal processing unit 68 via 6. Signal processing unit 68
Is a digital signal processor (D including a brightness / color difference signal generation circuit, a gamma correction circuit, a sharpness correction circuit, a contrast correction circuit, a white balance correction circuit, etc.
This is an image processing means composed of SP) and processes an image signal according to a command from the CPU 64.

The image data input to the signal processing unit 68 is a luminance signal (Y signal) and color difference signals (Cr, Cb signals).
Is stored in the memory 60 after being subjected to predetermined processing such as gamma correction. When displaying and outputting the captured image, the image data is read from the memory 60,
It is transferred to the display memory 70. The data stored in the display memory 70 is a signal of a predetermined system for display (for example,
After being converted to NTSC color composite video signal),
It is output to the liquid crystal monitor (LCD) 30 via the D / A converter 72. In this way, the image content of the image data is displayed on the screen of the liquid crystal monitor 30.

The image data in the memory 60 is periodically rewritten by the image signal output from the CCD 52,
The video signal generated from the image data is the liquid crystal monitor 3
By being supplied to 0, the image input via the CCD 52 is displayed on the liquid crystal monitor 30 in real time.
The photographer can confirm the image (through image) displayed on the liquid crystal monitor 30 or the photographing view angle by the optical viewfinder 28.

When the photographer operates the zoom switch 32, the instruction signal is input to the CPU 64, and the CPU 64
Controls the zoom drive unit 74 based on the signal from the zoom switch 32 to move the zoom lens 46 in the tele (TELE) direction or the wide (WIDE) direction. Zoom drive 7
Reference numeral 4 includes a motor (not shown), and the zoom lens 46 is driven by the driving force of the motor. The position (zoom position) of the zoom lens 46 is detected by the zoom position sensor 76, and the detection signal of the sensor 76 is input to the CPU 64.

Similarly, the focus driving section 78 includes a motor (not shown), and the driving force of the motor causes the focus lens 48 to move back and forth along the optical axis. The position of the focus lens 48 (focus position) is detected by a focus position sensor 80, and the detection signal of the sensor 80 is C
It is input to the PU 64.

When the still image photographing mode is set by the power / mode switch 20 and the shutter button 18 is pressed, a photographing start instruction (release ON) signal is issued. The CPU 64 detects the release ON signal and executes the image capturing operation for recording. That is, the CPU 64 controls the focus drive unit 7 based on the result of the evaluation value calculation described later.
8 is controlled to move the focus lens 48 to the in-focus position, and the exposure is controlled by controlling the aperture diameter of the diaphragm 50 and the electronic shutter of the CCD 52. Also,
The CPU 64 sends a command to the strobe control circuit 82 as needed to control the light emission of the slot light emitting unit 16.
The strobe light emitting unit 16 and the strobe control circuit 82
The details of will be described later.

Thus, in response to the pressing operation of the shutter button 18, the capture of the image data for recording is started. When the mode for compressing and recording the image data is selected, the CPU 64 sends a command to the compression / expansion circuit 84. The compression / expansion circuit 84 compresses the image data captured in the memory 60 according to a predetermined format such as JPEG.

The compressed image data is recorded in the memory card 24 via the card interface 86.
Mode for recording uncompressed image data (uncompressed mode)
If is selected, the compression processing by the compression / expansion circuit 84 is omitted, and the image data is recorded in the memory card 24 without being compressed.

When the reproduction mode is set by the power / mode switch 20, the image file is read from the memory card 24. The read image data is expanded by the compression / expansion circuit 84 as needed, and is output to the liquid crystal monitor 30 via the display memory 70.

The CPU 64 is a control unit which controls each circuit of the camera system. The CPU 64 controls the operation of the corresponding circuit based on input signals received from the power / mode switch 20, the shutter button 18, the zoom switch 32, and other operation parts, and also controls the strobe, the display on the liquid crystal monitor 30, and the autofocus. (AF) control and automatic exposure (AE) control are performed.

The autofocus control will be described here. The image signal converted into a digital signal by the A / D converter 58 is input to the evaluation value calculation unit 88. The evaluation value calculation unit 88 includes a high frequency component extraction circuit 90 and an integration circuit 9
2, the G component data of the input image signal is sampled to extract the high frequency component in the AF detection target area (hereinafter referred to as the focus area), and its absolute value is taken to determine the absolute value in the focus area. The CPU 64 is provided with a value (corresponding to an evaluation value) obtained by integrating the value data.

During the AF operation, the CPU 64 moves the focus lens 48 in the focus adjustment region from the closest to infinity (or from infinity to the closest) as shown in FIG. The contrast of the central portion of the image is detected at (search point), and an evaluation value (indicated by a black circle) is calculated for each search point as shown in FIG. Then, by integrating the evaluation values calculated at each point, the lens position having the maximum evaluation value is determined as the in-focus position, and the focus drive unit 78 is operated so as to move the focus lens 48 to the in-focus position obtained. Control.

Next, the strobe light emitting section 16 will be described.

The strobe light emitting section 16 has a strobe light source section 100 as shown in FIG. 5A is a sectional view of the strobe light source unit 100, and FIG. 5B is a front view of the strobe light source unit 100.

This strobe light source section 100 is provided with a reflector 10.
2 and the LED group 104 (R, G, B LEDs 104R,
104G, 104B) and a diffusion plate 106. R, G, B LEDs 104R, 104G, 10
As shown in FIG. 5B, a large number of 4Bs are arranged in an array. Further, the diffusion plate 106 diffuses the light having high directivity emitted from the LED group 104 so as to be uniform. The LEDs 104R, 104G, 104B
Does not have to be the same number, for example, each LED1
It is preferable to arrange the light sources so that white light is emitted when 04R, 104G, and 104B are fully emitted.

FIG. 6 is a block diagram of a strobe device including the strobe light emitting section 16, the strobe control circuit 82 and the like.

This strobe device includes a dimming sensor 17 for strobe dimming, an LED group 104, a voltage up converter 112 supplied with power from a battery 110, and a large-capacity capacitor as shown in FIG. 114, operational amplifiers 116, 118 and 120, a controller 122, a dimming circuit 124, and a temperature sensor 126 are provided.

The controller 122 integrally controls the strobe device, controls the voltage up-converter 112, boosts the voltage of the battery 110 (for example, 6 V) to about 10 V, and charges the capacitor 114 with this boosted voltage. . The capacitor 114 is charged for a long time of, for example, about 2 to 5 seconds, and is capable of continuously supplying a current to the LED group 104 for 1/60 seconds (about 16 ms) or more.

The electric energy accumulated in the capacitor 114 is supplied to the LEDs 104R, 104G, 104B of R, G, B through the operational amplifiers 116, 118, 120, and the controller 122 is the operational amplifier 1 described above.
LED1, R, G, B controlling 16, 118, 120
The emission time and emission amount of 04R, 104G, and 104B are controlled.

The controller 122 uses the CP shown in FIG.
Various signals such as a signal indicating the start of charging, a light emission signal synchronized with the shutter button 18, a light emission amount, and a signal indicating the light emission timing are fetched from U64. Since the light amount of the LED varies depending on the ambient temperature, a temperature sensor 126 for detecting the ambient temperature of the LED group 104 is provided, and the controller 122 controls the ambient temperature of the LED group 104 detected by the temperature sensor 126. Based on the LED group 104 so that the required light emission amount can be obtained regardless of the ambient temperature.
The current is controlled to.

Next, at the time of stroboscopic photography, the stroboscopic light emitting section 1
The operations of the CPU 64 and the controller 122 when the strobe light (hereinafter, referred to as “imaging auxiliary light”) 6 is emitted will be described.

First, the CPU 64 uses, for example, the camera power source O.
At the time of N, the charge start signal is output to the controller 122. When the charge start signal is input, the controller 122 outputs a signal instructing the voltage up converter 112 to charge the capacitor 114 to start charging the capacitor 114,
When the charging of 14 is completed, the voltage up converter 112
The charging operation is stopped and the CPU 64 is notified of the completion of charging.

After that, when the shutter button is pressed halfway, the controller 122 takes in information from the CPU 64, such as a guide number, for determining the flash emission amount. After that, when the shutter button is fully pressed to open the shutter, the CPU 64 outputs a light emission signal synchronized with the opening of the shutter to the controller 122, and the controller 12
2 uses the light emission signal to output control signals indicating predetermined R, G, B light emission levels to operational amplifiers 116, 118, respectively.
Output to the positive input of 120. Operational amplifiers 116 and 11
The LEDs 104R and 104 are connected to the negative inputs of 8 and 120, respectively.
Signals corresponding to the current values flowing in G and 104B are added, and the operational amplifiers 116, 118, and 120 generate constant currents corresponding to predetermined R, G, and B emission levels in each LED 10.
The flow is controlled so as to flow to 4R, 104G, and 104B.

As a result, the LED group 104 emits photographing auxiliary light of a required light amount.

When the photographing auxiliary light is emitted from the LED group 104, the dimming circuit 124 detects the amount of light emission via the dimming sensor 17. Then, when the detected light emission amount matches the reference value for light emission amount adjustment, a light emission stop signal is output to the controller 122 to stop light emission. Upon receiving the light emission stop signal from the dimming circuit 124, the controller 122 outputs a control signal for stopping the light emission of the LED group 104 to the operational amplifiers 116, 118, 120. As a result, the current flowing through the LED group 104 is cut off and the LED
The group 104 stops emitting light.

Next, the operation of the CPU 64 and the controller 122 when the strobe device is used as an AF auxiliary light emitting means will be described.

First, when the shutter button 18 is half-depressed, the CPU 64 performs AE control and AF control, and AF and A are operated while the shutter button 18 is half-depressed.
Lock E.

In the AE control, the R, G, B signals are taken in, the subject brightness (photographing EV value) is obtained based on the integrated value obtained by integrating these R, G, B signals, and this photographing EV
The aperture value and shutter speed at the time of shooting are determined based on the value. When the shutter button 18 is fully pressed, the aperture 50 is controlled so as to have the determined aperture value, and the charge accumulation time is controlled by the electronic shutter so as to have the determined shutter speed.

In the AF control, the focus lens 48 is moved to the in-focus position by the contrast AF described with reference to FIG.
When the V value) becomes equal to or less than a predetermined value, the strobe light emitting section 16 emits AF auxiliary light.

Hereinafter, the emission timing of the AF auxiliary light, the motor drive timing in the focus drive section 78, etc. will be described with reference to FIG.

When the shutter button is pressed halfway as shown in FIG. 7A, the AE control is performed as described above (see FIG. 7A).
(D)), the brightness of the subject is measured. When the brightness of the subject is less than or equal to a predetermined value, the AF auxiliary light is emitted for a minute light emission period t ₁ (FIG. 7 (E)). The emission period t ₁ of the AF auxiliary light is within the light receiving period in which the CCD 52 receives the subject light in order to obtain the image signal.

The amount of AF auxiliary light is the contrast A
It suffices that the evaluation value required for F be obtained, and it is made sufficiently smaller than the emission amount of the photographing auxiliary light (FIG. 7C). That is, AF
When the auxiliary light is emitted, the minimum amount of light required (about 30% of the optimum amount of light) is reduced to save power. In addition, the amount of light emitted from the strobe light emitting section 16 is determined by the LED group 10
This is done by controlling the current applied to the LED 4 or the number of elements that selectively emit light.

Subsequently, an image signal for obtaining an evaluation value is fetched from the focus area of the CCD 52 (see FIG. 7).
(F)), and thereafter, the focus motor is driven to move the focus lens by a predetermined amount (to the next search point) as shown in FIG. 4B (FIG. 7).
(G)).

When the focus lens moves to the next search point, the AF auxiliary light is emitted again and the image signal is fetched from the CCD 52. As shown in FIG. 4B, the AF auxiliary light is emitted at each search point while moving the focus lens in the direction from the closest point to the infinite point (or from the infinite point to the closest point) within the focus adjustment area, and the CCD 52 outputs the image signal. Take in.

When the evaluation value based on the image signal at each search point is calculated, the calculated evaluation values are combined, the lens position having the maximum evaluation value is calculated as the in-focus position, and the calculated result is obtained. Move the focus lens to the focus position,
The AF operation ends.

After that, when the shutter button is fully pressed (FIG. 7B), the photographing auxiliary light of the required light emission amount is emitted as described above (FIGS. 7C and 7E).

When the photographing auxiliary light is emitted in this manner, an image signal showing the subject photographed by the photographing auxiliary light is fetched from the CCD (FIG. 7 (E)).

As the stroboscopic light emitting means, R, G,
Instead of B's LEDs 104R, 104G, 104B,
An organic electroluminescence panel (organic EL panel), a plasma light emitting element panel in which plasma light emitting elements are arranged in an array, a milky white LED, or a xenon tube can be applied.

[0064]

As described above, according to the present invention, in the contrast AF in which the photographing lens is moved over the focus adjustment range and the evaluation value corresponding to the contrast component of the object is collected every time the photographing lens moves by a predetermined amount. , The AF auxiliary light is not continuously emitted during the movement of the taking lens, and is emitted every time the taking lens moves by a predetermined amount (that is, A
Since the F auxiliary light is emitted intermittently)
It is possible to reduce the power consumption required to emit the auxiliary light.

[Brief description of drawings]

FIG. 1 is an external view of a digital camera to which the present invention has been applied.

[Figure 2] Rear view of digital camera

FIG. 3 is a block diagram showing an internal configuration of a digital camera.

FIG. 4 is a diagram used for explaining contrast AF.

FIG. 5 is a diagram showing a structure of a strobe light source provided in a strobe light emitting section.

FIG. 6 is a block diagram of a strobe device including a strobe light emitting unit, a strobe control circuit, and the like.

FIG. 7 is a timing chart used for explaining a timing of emitting AF auxiliary light, a timing of driving a motor in a focus driving unit, and the like.

[Explanation of symbols]

10 ... Digital camera, 12 ... Shooting lens, 16 ... Strobe light emitting section, 17 ... Light control sensor, 18 ... Shutter button, 48 ... Focus lens, 52 ... CCD, 78 ... Focus drive section, 80 ... Focus position sensor, 82 ...
Strobe control circuit, 88 ... Evaluation value calculation section, 90 ... High frequency component extraction circuit, 92 ... Integration circuit, 100 ... Strobe light source section, 102 ... Reflector, 104 ... LED group, 104R ... R
LED, 104G ... G LED, 104B ... B LE
D, 106 ... Diffusion plate, 112 ... Voltage up-converter,
114 ... Capacitor, 116, 118, 120 ... Operational amplifier, 122 ... Controller, 124 ... Dimming circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 13/36 G03B 15/03 F 15/02 W X 15/03 15/05 17/02 G02B 7/11 N 15/05 D 17/02 G03B 3/00 AF terms (reference) 2H002 CD11 CD13 DB02 DB25 DB31 GA54 HA01 HA06 JA07 2H011 AA01 BA31 DA01 DA08 2H051 AA01 BA45 BA47 EB01 EB19 2H053 BA31 BA82 2H100 DD15

Claims (5)

[Claims] 1. An image pickup lens is moved over a focus adjustment range, an evaluation value corresponding to a contrast component of an object is obtained based on an image signal output from an image pickup means each time the image pickup lens moves by a predetermined amount, and the image pickup is performed. In the automatic focus adjusting device of the camera for obtaining the moving position where the evaluation value has a peak based on the moving position of the lens and the evaluation value obtained for each moving position and moving the photographing lens to the obtained moving position, An automatic camera assist system comprising: an AF auxiliary light emitting unit that emits auxiliary light; and a control unit that causes the AF auxiliary light emitting unit to emit AF auxiliary light each time the photographing lens moves by a predetermined amount. Focus adjustment device. 2. A brightness detecting means for detecting the brightness of a subject, wherein the control means, when the brightness of the subject detected by the brightness detecting means becomes a predetermined brightness or less, the AF assist. 2. The automatic focus adjusting device for a camera according to claim 1, wherein the AF auxiliary light is emitted from the light emitting means. 3. The camera according to claim 1, wherein the control means stops the AF auxiliary light from the AF auxiliary light emitting means while the photographing lens is moving by a predetermined amount. Automatic focus adjustment device. 4. The AF auxiliary light emitting means is also used as a light emitting means for emitting shooting auxiliary light at the time of stroboscopic photography, and the light emitting means is a light emitting diode, organic electroluminescence,
4. The automatic focus adjusting device for a camera according to claim 1, wherein the automatic focus adjusting device is constituted by any one of a light emitting element of the plasma light emitting element and the plasma light emitting element. 5. The control unit reduces the light amount of the AF auxiliary light to be lower than the light amount of the photographing auxiliary light by controlling the current applied to the light emitting element or the number of elements to selectively emit light. The automatic focus adjusting device for a camera according to claim 4.