JP2000147368A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a camera that time required for an automatic focusing action can be shortened and a proper photographing action can be executed by controlling it so that a photographing mode is changed when a detected focusing position is not within a range corresponding to the photographing mode selected by a photographing mode selection means. SOLUTION: By a mode change-over switch 31, any photographing mode out of the macro-mode for close-up photographing and the normal mode for normal-distance photographing can be selected. Within the moving range corresponding to the photographing mode selected by a photographer, a scanning action is executed by a focus lens 20 first. When the focusing position is not detected within the moving range corresponding to the selected photographing mode, the scanning action is executed by the lens 20 within the moving range corresponding to the other photographing mode so as to detect the focusing position. Thus, the time required for the automatic focusing action can be shortened and the proper photographing action can be executed even when the mode is erroneously selected by the photographer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having an automatic focusing mechanism.

[0002]

2. Description of the Related Art In an electronic still camera which performs image pickup using an image pickup device such as a CCD, this image pickup device is usually used also for focus detection. That is, an autofocus (AF) operation is performed by using an image signal (luminance signal) output from the image sensor and scanning the focus lens so that a focus detection signal obtained from the image signal is maximized. (So-called hill-climbing AF method).

In the hill-climbing AF method, since the focus lens is scanned to detect the in-focus position, there is a problem that the time required for the AF operation becomes long. Therefore, the photographing mode (normal mode, macro mode) is set in advance by the photographer.
If focus detection is not performed within the range corresponding to the set mode, an appropriate position within the range (for example, infinity in the normal mode, general subject distance in the macro mode) ), A method of moving a focus lens has been proposed.
No. 160287).

[0004]

However, according to the above method, when focus detection is not performed within a range corresponding to the set mode, the focus lens is simply moved to an appropriate position in the range. However, if the photographer sets the mode incorrectly, there is a problem that appropriate photographing cannot be performed.

The present invention has been made to solve such a problem, and provides a camera capable of shortening the time required for an autofocus operation and capable of performing appropriate photographing by setting an appropriate mode. It is intended to be.

[0006]

A camera according to the present invention comprises:
A shooting mode selection unit for selecting one of a macro mode for close-up shooting or a normal mode for normal distance shooting, and a focus lens for focusing to a macro range corresponding to the macro mode and the normal mode. A drive unit that enables movement within a corresponding movement range including a normal range, a focus detection unit that scans a focus lens by the drive unit to detect a focus position, and a focus selection unit that is selected by the shooting mode selection unit. First, the focus lens is scanned in the movement range corresponding to one shooting mode, and if focus detection by the focus detection unit is not performed within the movement range, the focus lens is scanned in the movement range corresponding to another shooting mode. A focus control means for controlling a focus lens to scan so as to perform focus detection by the focus detection means; A function for setting a photographing condition based on the photographing mode, and setting the photographing mode when the focus position detected by the focus detecting means is not in a range corresponding to the photographing mode selected by the photographing mode selecting means. And control means for performing control to change.

The camera further includes a strobe light emitting means and an aperture means for mechanically restricting the light quantity of the photographing light beam, and the control means controls the position of the focus lens at which the focus is detected when the strobe light is emitted. It is preferable that the camera has a function of calculating a shooting distance based on the calculated shooting distance, and controlling the aperture unit based on the calculated shooting distance.

It is preferable that the driving means uses a stepping motor as a driving source and drives the stepping motor in a micro step at least in a macro range corresponding to a macro mode.

The camera further includes a strobe light emitting means, a stop means for mechanically limiting the light amount of the photographing light beam, and a zoom lens, and the control means controls the focus at a constant zoom position when the strobe light is emitted. In the case where the distance is equal to or longer than the distance, it is preferable to have a function of calculating a photographing distance based on the position of the focus lens in which the focus is detected, and controlling the diaphragm unit based on the calculated photographing distance.

According to the present invention, since the focus lens is first scanned in the moving range corresponding to the photographing mode selected by the photographing mode selecting means, focus detection is normally performed within the selected range. And the time required for the autofocus operation can be reduced. Also,
If focus detection was not performed within the movement range corresponding to the selected shooting mode, focus detection was performed by scanning the focus lens in the movement range corresponding to the other shooting mode. It is possible to perform appropriate photographing even when a user makes a mistake in mode selection.

[0011]

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

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

In FIG. 1, reference numeral 11 denotes a system controller, which controls each part of the camera. A zoom circuit 12, an aperture circuit 13, and a focus motor drive circuit 14 are connected to the system controller 11, and a zoom lens 18, an aperture 19, and a focus lens 20 are connected to the system controller 11 via a zoom motor 15, an aperture actuator 16, and a focus motor 17, respectively. Operation is controlled. Note that a stepping motor is used as the focus motor 17, and this stepping motor is driven by microstepping as necessary. The output of the reset sensor 21 is input to the system controller 11.
A reset position of 0 is detected.

The subject image passing through the zoom lens 18, the aperture 19, and the focus lens 20 is formed on an image sensor 22 using a CCD, and the image sensor 22 photoelectrically converts the image into an electric signal corresponding to the amount of incident light. It has become.
The image sensor 22 also has a function as a distance sensor for detecting a distance to a subject. The output (image signal) of the image sensor 22 is supplied to the A / D
The data is input to the conversion circuit 24 and is converted into digital data by the A / D conversion circuit 24.

The output of the A / D conversion circuit 24 is stored in a buffer memory 25.
Are subjected to predetermined processing by a compression / expansion circuit 26, and then stored in a recording medium 27.

The output of the A / D conversion circuit 24 is connected to a focus detection circuit 28 and an AE circuit 29. The outputs of the focus detection circuit 28 and the AE circuit 29
1 has been entered.

The system controller 11 is connected to a mode switch 31 in addition to the release switch 30. With this mode changeover switch 31, it is possible to select any one of a shooting mode of a macro mode for close-up shooting or a normal mode for normal distance shooting,
The shooting conditions and the like are set by the system controller 11 based on the selected shooting mode.

The system controller 11 further includes a strobe circuit 32
Is connected, and the light emission of the strobe 33 is controlled by the strobe circuit 32.

Next, the principle of the autofocus function of the camera shown in FIG. 1 will be described with reference to FIG.

In FIG. 2, an area closer to the subject at a distance of 60 cm is defined as a macro area and an area farther than the macro area is defined as a normal area. The switch 31 allows the user to select a shooting mode (macro mode or normal mode) corresponding to any area.

Movement example 1 is an example in which the initial position of the focus lens when the macro mode is selected is set to the closest position, and the initial position of the focus lens when the normal mode is selected is set to infinity. It is.

In the first movement example, when the macro mode is selected, the scanning of the focus lens is started from the closest position, and when the focus is not detected in the macro area, the focus lens is continuously moved in the normal area. Scanning is performed. When the focus is detected in the normal area, that is, when the focus detection circuit 28 detects the local maximum point of the contrast based on the image signal obtained by the image sensor 22 in FIG. The position becomes the focus position.

In the first movement example, when the normal mode is selected, the scanning of the focus lens is started from the infinity position, and when the focus is not detected in the normal area, the focus lens continues to be scanned in the macro area. Scanning is performed. When the focus is detected in the macro area, that position becomes the focus position.

In movement example 2, both when the macro mode is selected and when the normal mode is selected,
This is an example when the initial position of the focus lens is set at the boundary between the macro area and the normal area.

In the second moving example, when the macro mode is selected, scanning of the focus lens is started from the boundary position between the macro region and the normal region toward the closest position. If the focus is not detected in the macro area, the focus lens is returned to the initial position, and the focus lens is continuously scanned in the normal area. When the focus is detected in the normal area, that position becomes the focus position.

In the second movement example, when the normal mode is selected, scanning of the focus lens is started from the boundary position between the macro region and the normal region toward the infinite position. If the focus is not detected in the normal area, the focus lens is returned to the initial position, and the focus lens is continuously scanned in the macro area. When the focus is detected in the macro area, that position becomes the focus position.

In the moving example 3, both when the macro mode is selected and when the normal mode is selected,
This is an example of a case where the initial position of the focus lens is set to an appropriate position in each selected area.

In the third movement example, when the macro mode is selected, the scanning of the focus lens is started from the initial position in the macro area to the closest position.
If the focus is not detected in the macro area, the focus lens is returned to the boundary position between the macro area and the normal area, and the focus lens is continuously scanned in the normal area. When the focus is detected in the normal area, that position becomes the focus position.

In the third movement example, when the normal mode is selected, the scanning of the focus lens is started from the initial position in the normal area toward the infinity position. If the focus is not detected in the normal area, the focus lens is returned to the boundary position between the macro area and the normal area, and the focus lens is continuously scanned in the macro area. When the focus is detected in the macro area, that position becomes the focus position.

Next, a more specific operation of the camera shown in FIG. 1 will be described with reference to the flowcharts shown in FIGS.

When the release switch 30 of FIG. 1 is turned on (S1), the output from the image sensor 22 is received, and the AE circuit 29 detects the light amount (S2). Subsequently, it is determined whether to turn on the strobe (S3).

When turning on the strobe, it is determined whether the mode switch 31 is on the macro mode side or the normal mode side (S4).

When the mode changeover switch 31 is on the macro mode side, the photographing mode is set to the macro mode (S5), and the focus lens 20 is moved to the initial position of the macro area (S6). This initial position is as shown in FIG. Subsequently, the AF operation (hill climbing AF) is started in the macro area (S7). That is, the focus lens 20 is scanned in the macro area, and the image sensor 22 is scanned.
The focus detection operation is performed by the focus detection circuit 28 using the image signal from the camera. When the in-focus state is detected in the macro area (S8), the process proceeds to step S21 described later.

If no focus is detected in the macro area (S8), the focus lens 20 is moved to the normal area, and the focus lens 20 is scanned in the normal area to perform the AF operation (S9). When the focus is not detected even in the normal area (S10), a warning is issued by a predetermined method (S10).
11). When focus is detected in the normal area (S1
0), the shooting mode is changed from the macro mode to the normal mode (S12), and the process proceeds to the step S21 described later.

In step S4, when the mode changeover switch 31 is in the normal mode side, the photographing mode is set to the normal mode (S13), and the focus lens 20 is set.
Is moved to the initial position of the normal area (S14). Subsequently, the AF operation (hill climbing AF) is started in the normal area (S
15) The focus detection operation is performed by the focus detection circuit 28. When the in-focus state is detected in the normal area (S16), the process proceeds to S21 described below.

When the focus is not detected in the normal area (S16), the focus lens 20 is moved to the macro area, and the AF operation is performed in the macro area (S17). When focus is not detected even in the macro area (S18), a warning is issued by a predetermined method (S19), and when focus is detected in the macro area, the shooting mode is changed from the normal mode to the macro mode (S20). ).

When the focus is determined in step S8, step S10, step 16 or step 18, the position of the focus lens 20 at that time is confirmed (S2).
1) The shooting distance is calculated from the position of the focus lens (S22). The calculation of the shooting distance is specifically performed by counting the number of pulses of the step motor (focus motor 17) with reference to the reset position obtained by the reset sensor 21. In addition, when the focus lens is driven by the step motor, if the step motor is driven in micro steps at least in a macro area, the shooting distance can be more accurately obtained. Further, the moving distance of the focus lens with respect to the change of the photographing distance is larger in the macro area, so that the photographing distance can be accurately obtained in the macro area.

Next, it is determined whether the calculated distance is a distance at which a flashmatic operation is possible, in other words, whether the calculated distance is equal to or less than a predetermined distance (for example, 2 m) (S31). If the distance is not short, sufficient accuracy cannot be obtained.

If the calculated distance is equal to or less than a predetermined distance (for example, 2 m), a macro strobe mode (flashmatic mode) is set, and a flashmatic operation is performed (S32). In the macro flash mode, the aperture value is calculated from the distance information and the guide number of the flash (S33), and the flash emission conditions are set based on the aperture value (S34). For example, an operation setting such as controlling the aperture 19 based on the calculated aperture value is performed. After that, exposure (S35) and light emission (S36) are performed, and the captured image data is stored in the memory 2
5 (S37).

If the calculated distance is equal to or longer than a predetermined distance (for example, 2 m), a normal strobe mode is set (S38), and strobe light emission conditions are set based on the pre-flash operation (S39) (S40). , And further exposure (S4
1) and light emission (S42) are performed, and the captured image data is recorded in the memory 25 (S43).

If the strobe is not turned on in step S3, the process proceeds to step 51. The operations in steps 51 to 67 are the same as the operations in steps S4 to S20, and a description thereof will be omitted. Step S55,
When the focus is determined in step S57, step 63, or step 65, exposure (S68) is performed, and the captured image data is recorded in the memory 25 (S6).
9).

In the embodiment described above, the operation of the zoom lens is not specifically mentioned. However, when the zoom lens is operated, the following control can be performed.

When operating the zoom lens, when the zoom lens is at the telephoto position, the depth of field is reduced. Therefore, in order to prevent the focus from becoming loose, the scanning interval of the focus lens for focusing (the interval L between the focus detection points) is made finer than when the zoom lens is at the wide-side position, as shown in FIG. Set. Thereby, although the total detection time becomes longer, the focus detection accuracy, that is, the measurement accuracy of the subject distance is improved.

In this case, there are two parameters for the subject distance measurement accuracy: the photographing distance and the zoom position (focal length). As shown in FIG. 7, the photographing distance is in the macro mode and the zoom position is on the tele side. In this case, sufficient subject distance accuracy can be obtained, so that flashmatic control is performed. For other combinations, sufficient subject distance accuracy cannot be obtained, so pre-emission control is performed.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
Various modifications can be made without departing from the spirit of the invention.

[0046]

According to the present invention, the focus lens is first scanned in the moving range corresponding to the photographing mode selected by the photographer, and focus detection is performed within the moving range corresponding to the selected photographing mode. If not performed, focus detection is performed by scanning the focus lens in the movement range corresponding to the other shooting mode, so that the time required for the autofocus operation can be shortened and the photographer can perform the autofocus operation. Appropriate shooting can be performed even when the mode selection is incorrect.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing the principle of an autofocus function of the camera shown in FIG.

FIG. 3 is a flowchart showing a part of an operation example of the camera shown in FIG. 1;

FIG. 4 is a flowchart showing a part of an operation example of the camera shown in FIG. 1;

FIG. 5 is a flowchart showing a part of an operation example of the camera shown in FIG. 1;

FIG. 6 is a diagram showing that the scanning interval of the focus lens is set to be smaller when the zoom lens is on the telephoto side than when the zoom lens is on the wide side.

FIG. 7 is a diagram showing that flashmatic control is performed when the shooting distance is in the macro mode and the zoom position is on the telephoto side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Syscon 12 ... Zoom circuit 13 ... Aperture circuit 14 ... Focus motor drive circuit 15 ... Zoom motor 16 ... Aperture actuator 17 ... Focus motor 18 ... Zoom lens 19 ... Aperture 20 ... Focus lens 21 ... Reset sensor 22 ... Image sensor 23 ... Imaging circuit 24 A / D conversion circuit 25 Memory 26 Compression / expansion circuit 27 Recording medium 28 Focus detection circuit 29 AE circuit 30 Release switch 31 Mode switching switch 32 Strobe circuit 33 Strobe

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H011 AA03 BA31 CA01 CA19 CA21 DA06 DA07 2H051 AA00 BA47 BA66 DD20 EB04 EB07 EB08 EB13 EB16 FA63 FA76 2H053 AA05 AB03 AB06 AD01 BA75 BA76 BA82 DA04 5C022 AA13 AB03 AB12 AB AC32 AC42 AC54 AC56 AC69 AC74

Claims (4)

[Claims] 1. A photographing mode selecting means for selecting a photographing mode of a macro mode for close-up photographing or a normal mode for normal distance photographing, and a focusing lens for focusing a macro range corresponding to the macro mode. And a drive unit that enables movement within a movement range including a normal range corresponding to the normal mode; a focus detection unit that scans a focus lens by the drive unit to detect a focus position; First, the focus lens is scanned in a movement range corresponding to one shooting mode selected by the means, and if focus detection is not performed by the focus detection means within the movement range, the focus mode is switched to another shooting mode. A focus control means for controlling the focus detection means to perform focus detection by scanning a focus lens in a corresponding movement range; and A function for setting a photographing condition based on the photographing mode selected by the selecting means, wherein a focus position detected by the focus detecting means is not in a range corresponding to the photographing mode selected by the photographing mode selecting means. A control unit for performing control to change a shooting mode in such a case. 2. A flash light emitting means, and a diaphragm means for mechanically restricting a light quantity of a photographic light beam, wherein the control means, based on the position of the focus lens detected in focus when the flash light is emitted. To calculate the shooting distance,
2. The camera according to claim 1, wherein the camera has a function of controlling the aperture unit based on the calculated shooting distance. 3. The apparatus according to claim 1, wherein said driving means uses a stepping motor as a driving source, and drives the stepping motor in a micro step at least in a macro range corresponding to the macro mode. The described camera. 4. A flash light emitting means, a stop means for mechanically restricting a light quantity of a photographing light beam, and a zoom lens, wherein said control means controls a zoom position to be equal to or greater than a predetermined focal length when the strobe light is emitted. 2. In the case of (1), a function is provided for calculating a photographing distance based on the position of the focus lens detected in focus, and controlling the aperture means based on the calculated photographing distance. The camera according to.