JP2880833B2 - Auto focus camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active type autofocus camera, and more particularly to an improvement in means for switching from a multipoint ranging mode to a single point ranging mode.

[0002]

2. Description of the Related Art In a conventional auto-focus camera, a range to be measured (hereinafter referred to as a focus target) is extremely limited with respect to a photographing screen. Unless it is arranged at a position, there is a disadvantage that it is not possible to take a picture in focus on the object.
In general, a conventional autofocus camera sets only the center part of the shooting screen as the focus target, so when two subjects are lined up, the focus of the shooting lens is set to infinity. There is a risk that shooting may be performed in a state where the camera is in a closed state. On the other hand, an autofocus camera having a so-called prefocus function has been proposed in such circumstances, but in such a camera, an object to be photographed is set within a focus target and a distance measurement operation is performed. It is necessary to redirect the camera to the screen to be photographed and perform the photographing operation, which has a disadvantage that the operation becomes complicated.

[0003] In order to solve these drawbacks,
A so-called multi-point distance measuring method for measuring a plurality of points in a screen has been proposed. The following is an example of a conventionally known autofocus camera using such multipoint ranging. (1) A method of focusing on the closest distance measurement result among a plurality of distance measurement results. (2) Focusing on the closest distance from the nearest distance measurement value / distance measurement point or a method of focusing on a plurality of distance measurement results. There is a value obtained by using an intermediate value of the distance measurement result within a certain range, for example, a method of selecting whether to focus on an average value or the like.

However, the method of the above (1) has a problem that when there is an obstacle in front of the main subject or when there is a foreground, it is in focus and the main subject is not in focus. In the method of the above (2), the distance measurement value
Judging from the distance measurement point whether or not it is an obstacle, if it is an obstacle, ignore the closest distance and focus on the average value of a certain range with respect to the intermediate value. Focusing prevents near-side obstacles from being in focus.However, the distance measurement information at the center where the probability that the main subject exists is high is compared to the distance measurement information at the periphery. Since it is treated equally except for the judgment, there is a problem that the focus at the center becomes loose.

In order to solve these problems, a method has been proposed in which both a multi-point ranging mode and a conventional single-point ranging mode are provided and are switched by an external switch in accordance with photographing conditions (Japanese Patent Application Laid-Open No. Sho 61). -272725). According to this, when only a specific subject enters the shooting screen, the multipoint ranging mode is selected, and an unspecified number of sub-subjects are included in the screen together with the main subject. In such a case, the above-mentioned drawback can be solved by selecting the conventional single point ranging mode.

[0006]

However, in the above-described method, switching from the multi-point ranging mode to the single-point ranging mode needs to be performed by using an external button provided separately, so that focusing on a specific subject can be performed. In addition to the difficulty in operability in that the button operation must be performed,
It is expected that the space occupied by the main operation buttons will become a bottleneck in downsizing the camera.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an automatic focusing camera capable of switching a distance measuring mode only by operating a shutter without providing an external button. Aim.

[0008]

According to a first aspect of the present invention, there is provided a control system for performing a multi-point distance measurement by operating a first stage of a shutter release, and a first unit of the shutter release. Control means for driving and exposing the lens in a second stage operation following the second stage operation, and the shutter release
Multiple target markers in the viewfinder during the first stage
Means to blink the lamp sequentially, and the second stage operation during the blinking
Means for detecting the second stage operation and blinking when the second stage operation is detected
Means for selecting the distance measurement information of the target mark of
When the lens is driven, it is selected by the selection unit.
The focus is adjusted based on the distance measurement information of the target mark . According to the second aspect of the present invention , multi-point distance measurement is performed by the first-stage operation of the shutter release.
Control means and the first stage operation of the shutter release
Control means for driving and exposing the lens in the second stage operation
And means for counting the time during which the first stage operation is continued
And the time measured by the timing means is predetermined.
If the measured time is longer than the specified time compared to the specified time,
Select the single-point ranging mode if
Means for selecting a multi-point ranging mode, and the single-point ranging mode
The first stage operation of the shutter release when is selected
Sometimes multiple target marks in the viewfinder
The second stage operation is detected during the blinking, and the second stage operation is detected.
Distance measurement of the blinking target mark when an operation is detected
Means for selecting information, when the lens is driven.
Measuring the distance of the target mark selected by the selecting means.
The focus is adjusted based on the information .

[0009]

According to the present invention, it is determined whether or not the focus is locked based on the length of time during which the first-step operation of the shutter release is continued. It will be based on shooting.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that how many points in the screen are measured in the multi-point ranging mode is appropriately determined according to the use of the camera using the automatic focusing device, cost, and the like. In the following embodiment, FIG. A point P1 in the center of the screen shown in FIG.
The case of measuring a point will be described as an example.

FIG. 1 is a block diagram showing a configuration of a main portion related to an autofocus of an autofocus camera according to an embodiment of the present invention. In the figure, a release button 10 is provided with a first-stage release switch 11 that is turned on when halfway depressed, and a second-stage release switch 12 that is turned on when depressed. The detection signals of these switches 11 and 12 are sent to a timer control circuit 13 and a microprocessor unit (hereinafter, referred to as MPU) 14. Timer control circuit 13 and MPU
Connected to 14 is a clock generation circuit 15, which sends clock pulses to them. The timer control circuit 13 counts clock pulses from the rise of the ON signal of the first release switch 12 to the rise of the ON signal of the second release switch 13,
This count signal “t” is sent to the MPU 14.

The MPU 14 is a first button of the release button 10.
The step operation is detected by the signal of the detection switch 11, and after this detection, a light emission signal is sent to the light emission control circuit 20. The light emission control circuit 20 causes the light emitting unit 21 to emit light based on the light emission signal. The light projecting unit 21 is composed of three light emitting elements 22, 23, 24 and light projecting lenses 25, 26, 27, and corresponds to three points P1, P2, P3 in the screen shown in FIG. Light is projected onto the subject corresponding to these three points in order to measure the distance to the subject. The light receiving section 30 is configured by an element that receives the reflected light from the subject projected by the light projecting section 20, and the light receiving signal is sent to the distance measuring circuit 31. Distance measuring circuit 31
Calculates the distance measurement data of each point based on the received light signal,
This is sent to MPU14.

The MPU 14 includes a timer control circuit 1
3 is compared with a signal "T" corresponding to a preset reference time, and distance measurement data to be used is selected based on the comparison result. Then, the lens driving circuit 33 is controlled based on the selected distance measurement data.
The lens drive circuit 33 sets the photographing lens unit 34 at a predetermined focal position. Further, when the second step operation of the release button 10 is detected by the signal of the detection switch 12, the MPU 14 operates the well-known shutter driving unit 35 and the exposure control unit 36 to perform photographing by automatic exposure.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, when the photographer presses the shutter release button 10, the first release switch 11 is turned on, the timer control circuit 13 is driven, and the counting of clock pulses from the clock generation circuit 15 is started. At the same time, a light emission signal is given to the light emission control circuit 20 by the MPU 14. As a result, the light emission control circuit 20 causes the light emitting elements 22, 23, and 24 to emit light sequentially. The reason why the light-emitting elements 22 to 24 sequentially emit light in time series is that the light-receiving unit 30 is formed of one light-receiving element. Therefore, when a plurality of light receiving elements are provided corresponding to the light emitting elements 22 to 24, light may be emitted simultaneously.

The output light from the light emitting elements 22 to 24 is reflected by the object, forms a real image on the surface of the element of the light receiving section 30, and a signal from the light receiving element receiving the reflected light is sent to the distance measuring circuit 31. . The distance measuring circuit 31 sequentially calculates the distance to the subject corresponding to each of the distance measuring points P1, P2, and P3 in the screen shown in FIG. This distance measurement data is MPU14
Is read in.

Subsequently, when the shutter release button 10 is pushed to the second stage, the second release switch 12
Turns on, the timer control circuit 13 stops counting clock pulses. Then, as shown in FIG. 4, the number of clock pulses “t” corresponding to the ON duration of the first release switch 11 until the second release switch 12 is pressed is output to the MPU 14. MPU1
4 compares “t” with the number of pulses “T” corresponding to a predetermined time. If t ≧ T, it is determined that the AF switch is in the AF locked state by half-pressing the release switch button 11, that is, the target mark 41 in the viewfinder 40 shown in FIG. 5 is directed to a specific subject by the photographer. , The focus position is calculated based on the center beam, that is, the distance measurement information obtained only from the light emitting element 22.

If t <T, the MPU 14 determines that the half-press time of the release switch button is short and the AF lock is unnecessary, and the multi-beam, that is, the light emitting elements 22, 23, 2
The focal position is calculated based on the distance measurement data of each point according to 4. Then, the photographing lens unit 34 is driven by the lens driving circuit 33 based on the calculation result, and the photographing lens unit 34 is set to the calculated focal position. In addition,
If the distance measurement data obtained by the light projecting elements 22, 23, and 24 has a variation in distance, the focusing is performed on the closest distance measurement result.

In the above embodiment, as shown in FIG. 5, only one target mark 41 in the finder 40 corresponding to the center beam is used.
At the time of photographing using the lock, that is, photographing based on the single-point distance measurement data, as shown in FIG. When the target mark is blinking, the second-stage operation of the shutter release may be performed to calculate the focal position based on the distance measurement data at the blinking single point.

[0019]

As described above, according to the present invention,
Switching of the photographing mode by the conventional single-point ranging or multi-point ranging can be performed only by operating the shutter release, and the operability can be improved. In addition, there is an effect that a switching button is not required, and a space saving corresponding to a demand for downsizing the camera can be achieved. This allows
It is possible to easily perform photographing by taking advantage of the advantages of the conventional multi-point ranging and single-point ranging. Furthermore, shutter
-When the first step of the release
Target mark blinks in sequence, and during this blinking,
Operation is detected, and when this second stage operation is detected,
Select the distance measurement information of the target mark and
Focus adjustment based on the
This eliminates the need for work and makes shooting easier.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an autofocus camera embodying the present invention.

FIG. 2 is an explanatory diagram showing a light projecting position of a light projecting element in a screen of the camera.

FIG. 3 is a flowchart showing an operation sequence of the camera.

FIG. 4 is a time chart of a timer control circuit.

FIG. 5 is an explanatory diagram showing information in a finder.

FIG. 6 is an explanatory diagram showing information in a finder according to another embodiment.

[Explanation of symbols]

 Reference Signs List 10 shutter release button 11 first release switch 12 second release switch 13 timer control circuit 14 MPU 21 light emitting unit 30 light receiving unit 31 distance measuring circuit 40, 44 finder screen 41, 45, 46, 47 target mark

Claims (2)

(57) [Claims] 1. The distance to a plurality of objects is multi-pointed by controlling the light emission of a plurality of light emitting elements simultaneously or in time series.
In an autofocus camera for measuring a distance, control means for performing multi-point distance measurement by a first-step operation of a shutter release, and control means for driving and exposing a lens by a second-step operation following the first-step operation of the shutter release And the viewfinder during the first stage operation of the shutter release
Means for sequentially blinking a plurality of target marks within the target, means for detecting a second-stage operation during the blinking, and a blinking target mark when the second-stage operation is detected.
Means for selecting the distance measurement information of the camera, and when the lens is driven , the distance selected by the selection means is provided.
An auto-focus camera , wherein the focus is adjusted based on distance measurement information of a target mark . 2. A method for simultaneously or chronologically connecting a plurality of light emitting elements.
Multi-point distance to multiple subjects by controlling light emission
Multi-point ranging to measure the distance and focus based on this multi-point ranging information
Single point focusing based on mode and distance measurement information of only one point
Control to perform multi-point ranging by the first-stage operation of the shutter release in an autofocus camera having a ranging mode
Means and second stage operation following the first stage operation of the shutter release
Control means for driving and exposing the lens by means of: a time measuring means for measuring the time during which the first-stage operation is continued; and a predetermined time measured by the time measuring means.
If the measured time is longer than the specified time,
Selects the single-point ranging mode.
Means for selecting a ranging mode, and a shutter release when the single-point ranging mode is selected.
Multiple targets in the viewfinder during the first stage of Leeds
Flashes in sequence, and during this
Blinks when the second stage operation is detected.
Means for selecting distance measurement information of a get mark, wherein when the lens is driven , the distance selected by the selection means is selected.
An auto-focus camera , wherein the focus is adjusted based on distance measurement information of a target mark .