JPH1152225A - Camera provided with automatic focus detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a camera provided with an automatic focus detecting mechanism capable of choosing one of auxiliary light projection parts suitable for the attitude of the camera at the time of taking a photograph and a selected range-finding area and further, one of auxiliary light projection parts, with the luminance of an object, as necessary, so as to make the chosen auxiliary light projection part emit light. SOLUTION: The auxiliary light projection parts 11 and 12 for detecting a focus are arranged in both side positions of the optical axis O of a photographic lens 3, in the front part of a camera main body 2 at least by one in each position. Further, an attitude detecting means capable of detecting the attitude of the camera is provided and it is chosen whether either of the auxiliary projection parts on both sides emits the light or not by the detected attitude of the camera. It is chosen whether either of the auxiliary projection parts emits the light or not by the range-finding area selected out of the selectable range-finding areas of the object.

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 focus detection mechanism called an autofocus camera for automatically performing focus detection using an auxiliary light projection device.

[0002]

2. Description of the Related Art Conventionally, a camera equipped with this kind of automatic focus detection mechanism has one auxiliary light projection unit for focus detection. Such an auxiliary light projection unit is generally disposed at a position on the front surface of the camera body, which is shifted to one side from the lens optical axis of the photographing lens.

FIG. 13A shows a conventional general camera 1. One auxiliary light for focus detection is located at a position closer to the grip 2a than the lens optical axis O of the photographing lens 3 on the front surface of the camera body 2. A projection unit 4 is provided.

[0004]

However, as described above, one auxiliary light projection unit 4 is connected to the grip unit 2 of the camera body 2.
As shown in FIG. 13 (b), when the camera 1 is held in the vertical position during photographing, the auxiliary light projection unit 4 may be covered and hidden by hand, because the camera 1 is provided at a position shifted toward a. In this case, the effect of the auxiliary light cannot be obtained for the subject, and the focus detection accuracy may be reduced, or attention must be paid to how the auxiliary light is projected.

Further, in the camera 1 capable of selecting a distance measurement area, the auxiliary light projection unit 4 may be arranged on the opposite side of the selected distance measurement area with the lens optical axis O interposed therebetween. In the same manner as described above, there arises a problem that the focus detection accuracy is reduced.

Further, in the camera 1 having the above-described automatic focus detection mechanism, which does not adjust the light emission amount of the auxiliary light, the auxiliary light projection unit can be used even if the brightness of the subject is not so low. 4 emits light with the maximum light emission amount (so-called full light emission), which causes a problem that wasteful power is consumed.

The present invention has been made in view of such circumstances, and allows the user to freely select an auxiliary light projection unit suitable for the posture of a camera at the time of photographing and a selected ranging area. It is an object of the present invention to obtain a camera provided with an automatic focus detection mechanism that can select, as necessary, whether one or more auxiliary light projection units emit light depending on the brightness of the light.

[0008]

In order to meet such an object, a camera provided with an automatic focus detection mechanism according to the present invention is provided at a left or right position with the optical axis of a photographing lens interposed between front surfaces of a camera body. An auxiliary light projection unit for focus detection is provided.

Further, the camera provided with the automatic focus detecting mechanism according to the present invention includes posture detecting means capable of detecting the posture of the camera, and a left side of the camera is determined by the posture of the camera detected by the posture detecting means. , It is configured to select whether or not to emit any of the right auxiliary light projection units, and to project auxiliary light.

A camera provided with an automatic focus detection mechanism according to the present invention is configured so that a distance measuring area can be selected. It is configured to select whether or not to emit light from the light projection unit and project the auxiliary light.

Further, a camera provided with an automatic focus detecting mechanism according to the present invention includes an automatic focus detecting mechanism having two or more auxiliary light sources, and one or more auxiliary light sources of the camera depending on the luminance of a subject. Whether or not to emit light is selected, and auxiliary light is projected from the auxiliary light source.

According to the present invention, among the focus detection auxiliary light projecting units disposed on the left and right sides of the lens optical axis of the photographing lens, the position of the camera at the time of photographing and the selected ranging area are selected. It is possible to select a suitable auxiliary light projection unit and irradiate auxiliary light for focus detection.

According to the present invention, the amount of light emission for obtaining focus detection auxiliary light is adjusted by selecting whether one or more auxiliary light projection units are used in accordance with the luminance of the subject. Can be.

[0014]

1 and 2 show one embodiment of a camera provided with an automatic focus detecting mechanism according to the present invention. In these figures, the same or corresponding parts as those in FIG. The same reference numerals are given to the same parts, and the description is omitted.

In this embodiment, as shown in FIG.
Auxiliary light projecting units 11 and 12 for focus detection are provided on the left and right sides of the front side of the camera body 2 with the lens optical axis O of the taking lens 3 therebetween.

According to such a configuration, the auxiliary light projecting unit is not covered and concealed by a hand as in the prior art, and as shown in FIG. Although the portion 11 is covered by hand, the other auxiliary light projecting portion 12
Will not be covered. Reference numeral 5 in the drawing denotes a release button provided on the upper end side of the grip portion 2a of the camera body 2.

FIG. 3 is a flowchart showing the operation of the above-described camera 1 at the time of photographing.
In 101, it is determined whether or not the shooting preparation operation is performed by half-pressing the release button 5, and if so, S10
2 and photometry is performed by photometric means (not shown), and S1 is performed.
Go to 03.

In S103, the auxiliary light projection unit 1
Focusing (ranging) is performed by the auxiliary light from one of the light sources 1 and 12. For example, when the camera 1 is held as shown in FIG. 2, the auxiliary light from the auxiliary light projection unit 12 is used.

When a release operation is performed by fully pressing the release button 5 in S104, a film exposure associated with a shutter operation is performed in S105, a film is fed in S106, and the process returns to S101.

Here, in the above-mentioned camera 1, whether or not the auxiliary light projecting units 11 and 12 for focus detection emit light is lower than a certain level value (referred to as a threshold value). It is determined by whether or not. When the brightness value is high, the auxiliary light projection units 11 and 12 described above are used.
It is not necessary to emit light. When the brightness value is low,
The auxiliary light projection unit 11 or 12 or both are caused to emit light.

If the camera 1 shown in FIG. 1 is provided with some means (camera attitude detecting means) such as a mercury switch, which can detect the attitude of the camera, the camera can be set in the attitude shown in FIG. 1 or the attitude shown in FIG. 1 can be automatically detected, and the auxiliary light projection unit 11 or 12 on the required side can be automatically turned on to project auxiliary light.

That is, when the camera 1 is held in the vertical position as shown in FIG. 2, the auxiliary light projecting section 12 located above the lens optical axis O is selected to emit light, thereby enabling focus detection. Appropriate auxiliary light can be projected on the subject. Of course, depending on the photographer, when the camera 1 is held in the vertical position as described above, the auxiliary light projection unit 12 located above the lens optical axis O may be used.
In some cases, the auxiliary light projection unit 11 located below the lens optical axis O may be selected to emit light.

FIG. 4 is a flow chart for performing distance measurement (focusing) when the above-described measurement of the luminance value of the subject and the detection of the attitude of the camera are performed. In S201, the luminance value of the subject is measured. In S202, it is determined whether or not the luminance value is lower than a threshold value (a luminance value at the boundary of whether or not to emit the auxiliary light described above).
03, if higher, the process proceeds to S204, and the process proceeds to the distance measurement (focusing) in S209 without emitting the auxiliary light.

In S203, it is determined whether or not there is external auxiliary light. If there is external light, the process proceeds to S204 described above, and if not, the process proceeds to S205 to detect the posture of the camera. Then, in S206, it is determined whether or not the detection result in S205 is the posture of the vertical position. If the posture is not the posture of the vertical position, the process proceeds to S207, and the normal light emission position (for example, the auxiliary light projection unit on the left side in FIG. After performing the light emission in 11),
Proceed to S209.

If it is determined in step S206 that the camera is in the vertical position, the flow advances to step S208. In step S208, light is emitted from the appropriate auxiliary light projection unit (for example, the auxiliary light projection unit 12 on the right side in FIG. 1), and the flow advances to step S209. .

As described above, in the above-described embodiment,
According to the camera 1 in which the two auxiliary light projection units 11 and 12 are provided on the left and right sides of the lens optical axis O, a more appropriate auxiliary light projection is performed regardless of the posture of the photographer holding the camera 1. Part 11
Alternatively, 12 can be selected, and auxiliary light for performing focus detection on the subject can be projected as necessary.

FIG. 5 shows a display in the viewfinder of the camera 1 in which a distance measurement area can be selected. In FIG. 5, reference numeral 50 denotes a viewfinder field frame, and 50a denotes a viewfinder field. In the drawing, reference numerals 51, 52, 53, 54, and 55 indicate selectable distance measurement areas in the finder visual field 50a.

For example, in the conventional camera shown in FIG.
Focus detection is performed by causing the auxiliary light projection unit 4 provided near the grip unit 2a to emit light when any of the distance measurement areas 51 to 55 is selected. However, there is a problem in the following cases.
That is, when the distance measurement area 54 is selected in FIG. 5, the auxiliary light projection unit 4 on the opposite side of the object with the lens optical axis O interposed therebetween is caused to emit light. Is not being projected.

On the other hand, in the camera 1 according to the present invention, when the distance measuring area 52 is selected in FIG. 5, the auxiliary light projecting unit 11 of FIG. By causing the auxiliary light projection unit 12 in FIG. 1 to emit light, it is possible to project an appropriate auxiliary light on the subject for focus detection.

FIG. 6 is a flowchart for selecting the auxiliary light projection units 11 and 12 according to the selected distance measuring area to emit light in the camera capable of selecting the distance measuring area as described above. The same steps as those in FIG. 4 are denoted by the same step numbers, and description thereof is omitted.

When it is determined in step S203 that there is no external auxiliary light, it is determined in step S301 whether or not a distance measurement area has been selected. If the selection has been made, the appropriate auxiliary light projection unit (the auxiliary light projection unit 11 or 12 corresponding to the selected ranging area) emits light in S208, and then the process proceeds to S209.

If it is determined in step S301 that the distance measurement area has not been selected, the flow advances to step S207 to emit light at the normal light emission location (the auxiliary light projection unit 11 or 12), and the flow advances to step S209.

FIGS. 7 and 8A show another embodiment of a camera provided with an automatic focusing mechanism according to the present invention. In this embodiment, as shown in FIG. 1, the number of auxiliary light projection units to emit light is selected based on the luminance value of the subject by using the fact that the camera 1 includes two auxiliary light projection units 11 and 12. I can do it. By doing so, it is possible to project a light emission amount suitable for the luminance value of the subject.

For example, in a camera having only one auxiliary light projection unit, such as a conventional camera, the light emission amount cannot be adjusted. Therefore, if the luminance of the subject is lower than the luminance that is the auxiliary light emission condition, Irrespective of the magnitude of the luminance value, the auxiliary light is emitted with the maximum light emission amount (so-called full light emission). Therefore, when the brightness of the subject is a high value among the auxiliary light emission conditions, useless power is consumed.

On the other hand, in the camera 1 having the two auxiliary light projecting units 11 and 12 (or more auxiliary light projecting units) as in the present invention, the auxiliary light emitted according to the luminance of the subject is provided. By selecting the number of the projection units 11 and 12, it is possible to project a light emission amount suitable for the luminance of the subject.

As shown in FIG. 8A, a first threshold value and a second threshold value are sequentially determined in accordance with the luminance value of the subject from the higher luminance value. , The auxiliary light projection unit is not allowed to emit light, and one light is emitted from the first threshold to the second threshold, and two light is emitted when the luminance value is lower than the second threshold. . FIG. 3B shows the case where four auxiliary light projection units are provided, the first, second, third, and fourth threshold values are determined.
Two, three, and four light emission examples will be described.

FIG. 7 is a flowchart for selecting the number of lights to be emitted in the case of FIG. 8A, and the same steps as those in FIGS. 4 and 6 are denoted by the same step numbers. In step S201, the luminance value of the subject is measured. In step S401, it is determined whether the luminance value is lower than the first threshold value. If the luminance value is higher, the process proceeds to step S204, and the light emission is measured (focusing) in step S209 without emitting light. I do.

If it is determined in step S401 that the luminance value is lower than the first threshold value, it is determined in step S203 whether or not there is external auxiliary light.
It is determined whether it is lower than the threshold value. When it is higher than the second threshold value, the process proceeds to S403, in which the auxiliary light projection unit emits light only at one location, and then proceeds to S209. Also,
If it is determined in S402 that the value is lower than the second threshold value, the process proceeds to S404, in which the auxiliary light projection unit emits light at two places, and then proceeds to S209.

FIGS. 9 and 10 are flowcharts when the above-described embodiments are combined. The same or corresponding parts as those in FIGS. 4, 6, and 7 are denoted by the same step numbers. Detailed description is omitted. In this embodiment, the luminance value of the subject is selected to emit light from one or two auxiliary light projection units according to the first and second threshold values, and the auxiliary position at the appropriate position is detected by detecting the posture of the camera. The light projection unit is made to emit light, or an appropriate auxiliary light projection unit is made to emit light by selecting a ranging area.

The present invention is not limited to the structure described in the above embodiment, and it goes without saying that the shape and structure of each part can be appropriately modified and changed. For example, in FIG. 1, the auxiliary light projecting units 11 and 12 are disposed on the left and right near the upper end on the front surface of the camera body 2, but the lens light is projected on both sides of the pentaprism unit 6 as shown in FIG. It may be provided so as to be located on both sides of the axis O.

In the above-described embodiment shown in FIG. 7 and the like, the auxiliary light projecting unit 20 is provided on one side (or both sides) as shown in FIG. The light source 21, 22, 23, 24 may be provided.

[0042]

As described above, according to the camera provided with the automatic focus detecting mechanism according to the present invention, the auxiliary light projecting portions for focus detection are located at the left and right positions on the front surface of the camera body with the lens optical axis interposed therebetween. And an auxiliary light projection unit suitable for the posture of the camera at the time of photographing and the selected distance measurement area can be selected from among them to irradiate auxiliary light for focus detection.

In particular, according to the present invention, there is provided a posture detecting means capable of detecting the posture of the camera, and depending on the posture of the camera detected by the posture detecting means, the auxiliary light projecting portion of either the left or right of the camera is provided. By selecting whether or not to emit light and projecting the auxiliary light, it is possible to freely select an auxiliary light projection unit suitable for how the camera is held. Also,
According to the present invention, in the selectable ranging area of a subject, it is selected whether or not the left or right auxiliary light projection unit of the camera emits light according to the selected ranging area, and the auxiliary light is projected. By doing so, it is possible to freely select an auxiliary light projection unit suitable for the selected ranging area.

Further, according to the present invention, one or more auxiliary light sources emit at least one auxiliary light source according to the brightness of the object, and the auxiliary light source projects the auxiliary light, thereby providing an auxiliary light for focus detection. The amount of light emission for obtaining the power can be adjusted, and the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a camera including an automatic focus detection mechanism according to an embodiment of the present invention.

FIG. 2 is a front view showing an example when the camera of FIG. 1 is held in a vertical position during shooting.

FIG. 3 is a flowchart for explaining an outline of a main photographing operation of the camera.

FIG. 4 is a flowchart showing one embodiment of a camera provided with an automatic focus detection mechanism according to the present invention.

FIG. 5 is a diagram showing an example of display in a viewfinder of a camera capable of selecting a ranging area.

FIG. 6 is a flowchart showing another embodiment of the camera provided with the automatic focus detection mechanism according to the present invention.

FIG. 7 is a flowchart showing still another embodiment of the camera provided with the automatic focus detection mechanism according to the present invention.

FIGS. 8A and 8B are diagrams for explaining a threshold value according to a luminance value of a subject and a light emitting state of an auxiliary light projection unit.

FIG. 9 is a flowchart showing another embodiment of a camera provided with an automatic focus detection mechanism according to the present invention.

FIG. 10 is a flowchart continued from a part of FIG. 9;

FIG. 11 is a front view of a camera for explaining a modified example of the camera including the automatic focus detection mechanism according to the present invention.

FIG. 12 is a front view and a main part enlarged view of a camera for explaining still another modified example of the camera provided with the automatic focus detection mechanism according to the present invention.

13A and 13B show an example of a conventional camera provided with an automatic focus detection mechanism, and FIG. 13A is a front view of a camera in which one auxiliary projection unit for focus detection is arranged closer to one side than an optical axis of a photographing lens. (B) is a front view showing an example when the camera of (a) is held in a vertical position.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Camera provided with automatic focus detection mechanism, 2 ... Camera main body, 2a ... Grip part, 3 ... Photographing lens, 5 ... Release button, 6 ... Penta prism part, 11, 12; 20 ... Auxiliary light projection part, 21 22, 23, 24 ... auxiliary light source, 50a ...
Finder field of view, 51, 52, 53, 54, 55... Selected ranging area, O... Lens optical axis.

Claims (5)

[Claims] 1. A camera equipped with an automatic focus detection mechanism, wherein an auxiliary light projection unit for focus detection is disposed at left and right positions on the front side of the camera body with respect to an optical axis of a photographing lens. 2. A camera provided with an automatic focus detection mechanism according to claim 1, further comprising: posture detecting means capable of detecting a posture of the camera; A camera provided with an automatic focus detection mechanism, characterized by selecting whether or not to emit any of the right auxiliary light projection units and projecting the auxiliary light. 3. A camera provided with an automatic focus detection mechanism according to claim 1, wherein the camera is configured to be capable of selecting a ranging area, and the left and right sides of the camera are selected according to the selected ranging area of a subject.
A camera provided with an automatic focus detection mechanism, characterized by selecting whether or not to emit any of the right auxiliary light projection units and projecting the auxiliary light. 4. A camera provided with an automatic focus detection mechanism having two or more auxiliary light sources, wherein one or two or more auxiliary light sources of the camera are selected depending on the brightness of a subject, and the auxiliary light source is selected. A camera equipped with an automatic focusing mechanism, which projects auxiliary light from a light source. 5. A camera provided with an automatic focusing mechanism according to claim 4, wherein a plurality of auxiliary light sources are incorporated in an auxiliary light projecting unit provided at one position.