JPH11234548A - Video camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attain focusing even when changed over to manual focus setting in the case of conducting still image recording of a dark object by means of a strobe with an auxiliary light emission function for automatic focusing. SOLUTION: In the case recording a still image of an object 18 in the automatic focus mode, a strobe 13 emits and infrared auxiliary ray to detect the lightness of the object and photographs the object with a proper exposure. In the case of conducting still image recording when the object 18 is darker than a reference lightness and even manual focus setting is selected, the strobe 13 emits an infrared auxiliary ray to attain focusing easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera system having an autofocus function and capable of recording a still image.

[0002]

2. Description of the Related Art In recent years, video cameras have been automated and multifunctional in all aspects, such as AE (auto exposure) and AF (auto focus), so that good photographing can be easily performed. In recent years, the performance of video cameras has been improved, and the number of cameras capable of recording still images, such as digital still cameras, has been increasing. . In addition, some flashes have been built-in so that a still image can be taken more clearly, or an external flash can be attached.

In a camera equipped with a TV autofocus or the like, when a subject is dark, autofocus cannot be performed because the subject on the screen has no contrast.
For this purpose, the camera control unit controls the flash to emit the AF auxiliary light so as to brighten the subject. However, since a red LED (wavelength 700 nm) or the like is usually used as the auxiliary light source, the focus is set by the chromatic aberration of the lens. When the red LED is emitted, the camera controller corrects the focus so that the main focus is emitted when the strobe main light is emitted.

[0004] As described above, AF is used for photographing still images in darkness.
In a system using a strobe with a built-in auxiliary light, a system has been proposed in which an infrared LED is emitted as AF auxiliary light for autofocusing to perform focus correction.

FIG. 3 is a flowchart showing the processing operation of the conventional camera control unit as described above. Step 200
Is the start of this flow, and this process is repeated at a predetermined timing (a certain period) and started.

First, in step 201, it is determined whether or not a still image is being recorded.
And ends this flow without performing any processing. If a still image is not being recorded, the process proceeds to step 202.

In step 202, it is determined whether the camera is in a focus locked state (focus locked). If the camera is in the focus locked state, the process proceeds to step 214, and if not, the process proceeds to step 203.

In step 203, it is determined whether or not the two-stage still image recording switch is half-pressed. If the switch is half-pressed, the process proceeds to step 204; if not, the process proceeds to step 219 described above. To end the processing.

In step 204, the exposure is locked in synchronization with the half-press of the still image recording switch, and in step 20
Go to 5.

In step 205, it is determined whether or not the current focus mode is auto focus. If the camera is operating in auto focus, the process proceeds to step 206. If the camera is operating in manual focus, step 212 is performed.
Move to

In step 206, it is determined whether or not the brightness of the subject is equal to or less than the reference value. If the brightness is equal to or less than the reference value, the process proceeds to step 207. Move to

In step 207, it is determined that the subject is dark and autofocusing is impossible, and infrared auxiliary light for autofocusing is emitted.

In step 208, the focus position is corrected in consideration of the lens chromatic aberration during the emission of the infrared auxiliary light, and the flow advances to step 209.

In step 209, it is determined whether or not the subject is in focus. If the subject is in focus, the process proceeds to step 210, and if the subject is not in focus, the process proceeds to step 219 to end the process.

At step 210, the focus is locked upon receiving the focus determination, and the routine proceeds to step 211.

In step 211, the focus is locked with just focus and the auxiliary light for focusing is unnecessary, so that the auxiliary light is turned off, and the routine proceeds to step 214.

In step 212, the operation of the focus ring is monitored to determine whether or not the focus ring is rotating. If the focus ring is rotating, the process proceeds to step 213. If not, the process proceeds to step 214.

In step 213, the focus lens is driven in a direction corresponding to the rotation direction of the focus ring, and the flow advances to step 214.

At step 214, it is determined whether or not the above-mentioned still image recording switch is fully pressed. If the switch is fully pressed, the process proceeds to step 215. If not, the process proceeds to step 219 to end the process. I do.

In step 215, it is recognized that the switch for recording a still image is fully depressed, and pre-emission is performed to determine the amount of main light emission. The brightness of the subject is detected, and the flow advances to step 216.

In step 216, the main light emission amount is calculated and determined based on the result of the pre-light emission so as to obtain the proper exposure at the time of the main light emission.

In step 217, main light emission is performed based on the value determined in the above calculation, and the flow advances to step 218.

In step 218, recording of a picture synchronized with the main light emission is started, picture data is recorded in a memory, and recorded on a tape. Then, in step 219, this process ends.

As described above, the conventional AF auxiliary light (infrared LED) is built in so that the camera controller determines the brightness of the subject and can focus on a dark subject.
However, when switching to manual focus and photographing a very dark subject in a still image, the AF auxiliary light is emitted only during auto focus, and thus remains off during manual operation.

[0025]

Since the conventional video camera system is configured as described above, when recording a still image using a strobe with AF auxiliary light, autofocus control can be performed for a dark subject. Focusing is performed by irradiating the built-in AF auxiliary light as described above, but when switching to manual focus to shoot a still image of an extremely dark subject, the AF auxiliary light does not emit and the finder etc. can recognize the subject. However, it was difficult to focus on a manual focus and shoot a still image.

The present invention has been made in view of the above-described problems. When a still image of a dark subject is recorded,
An object of the present invention is to provide a video camera system capable of easily performing focusing and emitting a high-quality still image by emitting AF auxiliary light even when the setting is switched to manual focus.

[0027]

A video camera system according to the present invention is configured as follows.

(1) In a video camera using a flash device having an auxiliary light emitting function for autofocus, a switching means for switching between autofocus setting and manual setting, and a photometric means for measuring the brightness of a subject. When the setting of the focus is switched to manual, and when the brightness of the subject is equal to or less than a predetermined value and the recording of the still image is started, the flash device emits the auxiliary light for autofocus. I did it.

(2) In the system of (1), a switch having a plurality of outputs for starting recording of a still image is provided.

(3) In the above system (2), the switch is a two-stage press release switch,
The first flash of the release switch emits auxiliary light for autofocus by the flash device, and the second flash of the flash device shoots a still image.

(4) In the system of (1), a focus lock means for locking a focus state is provided, and when the focus state is locked, emission of the auxiliary light for autofocus is prohibited. .

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a video camera system according to the present invention. A strobe (flash device) having an auxiliary light emission function for autofocus is built in or can be mounted, and a still image is recorded and photographed. 1 shows a schematic configuration of a video camera capable of performing the following.

In FIG. 1, reference numeral 1 denotes a focus lens for focusing a subject 18, which is moved in the optical axis direction by a focus lens driving driver 17 to perform focusing. The light passing through the focus lens 1 is adjusted to an appropriate light amount by the stop 2 and passes through the zoom lens 3. The zoom lens 3 is a variable power lens for changing the magnification of the angle of view, and is adjusted to an appropriate amount of light by the diaphragm 2. Light passing through the zoom lens 3 forms an image on a light receiving surface of the CCD 4, and is electrically operated. It is photoelectrically converted into a signal.

The photoelectrically converted signal is read out from the CCD 4 by a reference clock, and is read by the CDS circuit 5 and the AG.
While being sampled / held by the C circuit 6, it is amplified with an optimum gain at the same time, and is converted by the A / D converter 7 into a digital signal synchronized with the reference clock. Then, only a specific frequency component is extracted by a BPF (bandpass filter) 8, and a signal of a specific portion in a captured image is extracted by a GATE circuit 9. The signal output from the GATE circuit 9 is input to a camera microcomputer (control unit) 11, and autofocus control is performed so that the signal value becomes maximum.

Here, the camera microcomputer 11 is a strobe 1
If 3 is mounted, its light emission amount, ON / OF of auxiliary light
F, data such as charging status are exchanged by communication, and when the two-stage switch for still image 12 is half-pressed and the subject 18 is dark in the auto focus state, the strobe 13 is caused to emit AF auxiliary light. connect. If focus is achieved by this auxiliary light, the camera microcomputer 11 locks the focus lens 1 and waits for the still image two-stage switch 12 to be fully pressed.

When the photographer confirms that the subject is in focus and fully presses the two-stage switch for still image 12, the camera microcomputer 11 controls the light emission amount of the strobe 13 so that the subject 18 is properly exposed. To emit the main light. The video synchronized with the light emission is written into the memory in the recorder control circuit 10, and is written as a still image on the tape for 6.5 seconds.

Note that the two-stage switch for still image 12
This is a step-press release switch. When the switch 12 is pressed in the first step (half-press), the strobe 13 emits auxiliary light for autofocus, and the second step is pressed (full-press).
Is configured to take a still image.

When the focus setting is switched to manual and the brightness of the subject 18 is equal to or less than a predetermined value, the camera microcomputer 11 starts recording a still image, When the step switch 12 is half-pressed, the strobe 13 emits auxiliary light for autofocus.

As described above, when a still image of a very dark scene is photographed using the strobe 13 with the AF auxiliary light emitting function, the auto focus auxiliary light is adjusted in accordance with the still image recording button even if the focus control is switched to manual. By emitting light, the degree of blurring of the subject 18 can be recognized, and even a dark subject that cannot be recognized by the viewfinder can be roughly focused. A high image can be recorded.

In FIG. 1, 14 is the focus ring described above, 15 is a driver for driving the zoom lens, and 16 is a driver for driving the aperture. Further, in the configuration of FIG. 1, a switching unit for switching the focus setting between the auto focus and the manual focus by the camera microcomputer 11 and a control unit for the strobe 13 are configured, and a focus lock unit for locking the focus state is also configured. When the focus state is locked, emission of the above-described autofocus auxiliary light is prohibited. Further, the two-stage switch for still image 12 is a still image recording start means having a plurality of outputs (here, two outputs of half-press and full-press).

FIG. 2 is a flowchart showing the operation of the video camera system of this embodiment. The processing control shown in this flowchart is executed by the camera microcomputer 11 according to a predetermined program.

Step 100 is the beginning of this flow, and is repeatedly started at a predetermined timing. First, in step 101, it is determined whether or not a still image is being recorded. If a still image is being recorded, the process proceeds to step 121 without performing any processing, and the flow ends. If a still image is not being recorded, the process proceeds to step 102.

In step 102, it is determined whether or not the focus is locked. If the focus is already locked, the process jumps to step 112 to determine whether the focus is fully pressed. Step 10 if focus is not locked
The process proceeds to step 3, where it is determined whether or not the still image two-stage switch 12 is half-pressed. If it is not half-pressed, the process proceeds to step 121 to end the process. If it is half-pressed, the process proceeds to step 104.

In step 104, the exposure is locked, and the flow advances to step 105 to determine whether or not the brightness of the subject 18 is equal to or less than the reference value.
Then, the flow advances to step S7 to determine whether or not the auto focus has been performed. If the value is equal to or less than the reference value, the process proceeds to step 106, and the auto-focus auxiliary light is emitted. In step 107, it is determined whether or not the autofocus is performed as described above. If the autofocus is performed, the process proceeds to step 108, where the focus shift due to the auxiliary light is corrected, and the process proceeds to step 109. If it is not auto focus, the process proceeds to step 113 to determine whether the focus ring 14 or the focus switch has been operated.

In step 109, it is determined whether or not the subject is in focus. If the subject is in focus, the process proceeds to step 110, the focus is locked, and the process proceeds to step 111. If the camera is not in focus, the flow shifts to step 121 to end the flow.
In step 111, since the focus is on, the auxiliary light is turned off, and the process proceeds to step 112. In step 112, it is determined whether or not the button is fully pressed.
Proceeding to 17, pre-emission is performed to detect the brightness of the subject 18. If the button has not been fully pressed, the process moves to step 121, and this flow ends.

In step 113, it is determined whether or not the focus ring has been operated as described above. If the focus ring has been operated, the flow advances to step 114 to drive the focus lens 1 in the rotation direction of the ring 14 or the operation direction of the focus button. If the operation has not been performed, the process proceeds to step 115. In step 115, it is determined whether or not the still image two-stage switch 12 has been fully pressed. If the switch has been fully pressed, the flow advances to step 116 to turn off the auxiliary light for autofocus. If it has not been fully pressed, the process moves to step 121 and the flow ends.

In step 117, pre-light emission is performed to detect the brightness of the subject 18, and the flow advances to step 118 to calculate the main light emission amount from the brightness data returned by the pre-light emission. In the next step 119, the main light emission is performed according to the calculation data corresponding to the pre-light emission, and the process proceeds to step 120 to start recording a still image synchronized with the main light emission. Then, the process proceeds to step 121, and this flow ends.

Here, the important point in the flow of the camera microcomputer 11 is that when the still image two-stage switch 12 is half-pressed, the brightness of the subject 18 is the reference regardless of whether the focus state is autofocus or manual. If the value is equal to or less than the value, auxiliary light is emitted. When the button is fully pressed, the auxiliary light is turned off, and recording of a still image is started.

[0050]

As described above, according to the present invention,
When the recording of a still image is started, regardless of whether the focus state is auto focus or manual focus, if the brightness of the subject is below the reference value, the auxiliary light is emitted, so an extremely dark subject where auto focus cannot be achieved is photographed. In such a case, even if the mode is switched to the manual focus, the auxiliary light is emitted to irradiate the subject, so that focusing can be easily performed, and a high-quality still image with just focus can be recorded.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a video camera system according to the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a flowchart showing the operation of the conventional example.

[Explanation of symbols]

 Reference Signs List 1 focus lens 4 CCD 10 recorder control circuit 11 camera microcomputer (focus lock means) 12 two-stage switch for still image (release switch) 13 strobe (flash device) 14 focus ring 18 subject

Claims (4)

[Claims] 1. A video camera using a flash device having an auxiliary light emission function for autofocus, comprising: switching means for switching between autofocus setting and manual setting; and photometric means for measuring brightness of a subject. Wherein the flash device emits autofocus auxiliary light when still image recording is started when the focus setting is switched to manual and the brightness of the subject is equal to or less than a predetermined value. A video camera system. 2. A switch having a plurality of outputs for starting recording of a still image.
The video camera system as described. 3. The switch is a release switch of a two-stage pressing type, wherein the first-stage pressing of the release switch emits auxiliary light for auto-focusing by the flash device, and the second-stage pressing of a still image. 3. The video camera system according to claim 2, wherein the video camera system is configured to perform photographing. 4. A device according to claim 1, further comprising a focus lock unit for locking a focus state, wherein when the focus state is locked, emission of the autofocus auxiliary light is prohibited. Item 1
The video camera system as described.