JP4797406B2 - Auto focus camera - Google Patents

Description

  The present invention relates to an autofocus camera, and more particularly to an autofocus camera having a plurality of focus detection areas (AF areas).

Recently, it has a plurality of focus detection areas (AF areas), and when a subject is dark, a stripe pattern for focus detection is projected onto the subject, and the reflected light from the striped pattern projected onto the subject is automatically used. An autofocus camera that performs focus detection has been proposed (see, for example, Patent Document 1).
JP 2001-337264 A

  However, in a conventional autofocus camera, a striped pattern projected onto a subject when the focal length of the photographing lens is changed or when an external auxiliary light projection device is used, a plurality of focus detection areas (AF areas) are detected. There is a problem that the focus detection is not performed correctly because the selected focus detection area (AF area) is not selected.

  The present invention has been made in view of the above problems, and has an auto focus that has a plurality of focus detection areas (AF areas) and can perform auto focus detection regardless of the focal length of the photographing lens and the type of the auxiliary light projection device. The purpose is to provide a camera.

In order to achieve the above object, the present invention provides an auxiliary light projection device that projects a focus detection pattern onto a subject and a focus using reflected light of the focus detection pattern for at least one of a plurality of focus detection regions. An automatic focus adjustment camera that has focus detection means for detecting, and performs focus adjustment based on the focus detection result of the focus detection means,
At least one focus detection for performing focus detection from the plurality of focus detection regions based on information from a photographing lens mounted on the camera and information from an auxiliary light projection device that projects the focus detection pattern Comprising a control means for selecting an area ;
When the control unit determines that the position of the focus detection area selected in advance deviates from the position where the focus detection pattern is projected, the control means moves the selected focus detection area in the vicinity of the selected focus detection area. In addition, the present invention provides an autofocus camera that changes to the focus detection area corresponding to the position where the focus detection pattern is projected .
The present invention also provides an auxiliary light projection device that projects a focus detection pattern onto a subject, and a focus detection unit that performs focus detection using reflected light of the focus detection pattern for at least one of a plurality of focus detection regions. In an automatic focus adjustment camera that adjusts the focus based on the focus detection result of the focus detection means,
At least one focus detection for performing focus detection from the plurality of focus detection regions based on information from a photographing lens mounted on the camera and information from an auxiliary light projection device that projects the focus detection pattern Comprising a control means for selecting an area;
The focus detection unit sets a plurality of the focus detection areas as a group of the focus detection target,
When the position of at least one focus detection area of the focus detection area in the group deviates from the position where the focus detection pattern is projected, the control means moves the defocused focus detection area in the vicinity of the group. In addition, the present invention provides an autofocus camera that changes to the focus detection area at a position where the focus detection pattern is projected.

  In the autofocus camera according to the present invention, it is preferable that information from the auxiliary light projection device is communicated to the control means.

In the autofocus camera according to the present invention, it is preferable that the auxiliary light projection device sets a projection magnification of the focus detection pattern based on information from the photographing lens.
In the autofocus camera according to the present invention, it is preferable that the information from the auxiliary light projection device is information on at least an irradiation range of the focus detection pattern.

In the autofocus camera according to the present invention, the control means may detect the focus detection selected in advance on the finder of the camera based on information from the photographing lens and information from the auxiliary light projection device. When it is determined that the area is out of the area of the focus detection pattern, the focus detection pattern is changed to the position where the focus detection pattern is projected in the focal distance detection area located closest to the preselected focus detection area. It is preferable to do.
In the automatic focus camera according to the present invention, when the control unit determines that the position of the pre-selected focus detection area deviates from the position where the focus detection pattern is projected, the selected focus detection area. Is preferably changed to the focus detection area corresponding to the position where the focus detection pattern is projected in the vicinity of the selected focus detection area.

In the automatic focus camera according to the present invention, the focus detection unit sets a plurality of focus detection areas as a group to be subjected to focus detection, and the control unit includes at least one of the focus detection areas in the group. When the position of one focus detection area deviates from the position where the focus detection pattern is projected, the defocused focus detection area is positioned near the group and the position where the focus detection pattern is projected. It is preferable to change to a certain focus detection area.

  According to the present invention, it is possible to provide an autofocus camera that has a plurality of focus detection areas (AF areas) and can perform autofocus detection regardless of the focal length of the photographing lens and the type of the auxiliary light projection device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram in which an auxiliary light projection device is mounted on an autofocus camera according to the present invention. FIG. 2 shows an example of the positional relationship between a projected focus detection pattern and a focus detection area (hereinafter referred to as an AF area) in the finder. FIG. 2A shows a focus detection pattern in which a part of the selected AF area is a focus detection pattern. (B) shows the case where the alternative AF area is reset in the column direction in place of the AF area removed in (a). FIG. 3 is another example of the positional relationship between the projected focus detection pattern and the focus detection area (hereinafter referred to as AF area) in the finder. FIG. 3A shows a part of the selected AF area as a focus. The case where it deviates from the detection pattern, (b) shows the case where the row direction alternative AF area is reset in place of the AF area deviated in (a). FIG. 4 shows another example of the positional relationship between the projected focus detection pattern and the focus detection area (hereinafter referred to as AF area) in the finder. FIG. 4A shows a part of the selected AF area in focus. The case where it deviates from the detection pattern, (b) shows the case where the alternative AF area is reset in the row direction, the column direction and the diagonal direction in place of the AF area deviated in (a). FIG. 5 is a flowchart for explaining an embodiment of the present invention.

(Embodiment)
In FIG. 1, a photographing lens 1 makes light of an object field incident, and a main mirror 3 divides the incident light into a focus detection system and a finder system (not shown). The light beam 5 to the focus detection system is reflected by the sub-mirror 7 after passing through the main mirror 3 and is incident on the focus detection means 9 to be used for distance measurement for automatic focus adjustment. Contrast is detected and sent to the CPU 11. The luminance or contrast information of the incident light from the CPU 11 is sent to the determination unit 13 of the auxiliary light projection apparatus A. When it is determined that the luminance or contrast of the subject is low, the auxiliary light projection unit 15 sends the information on the subject. A focus detection pattern 20 (see FIG. 2) composed of a combination pattern of a vertical stripe pattern and a horizontal stripe pattern, which will be described later, is projected. The stripe pattern used for the focus detection pattern 20 is not limited to a vertical stripe pattern and a horizontal stripe pattern, and an inclined stripe pattern may be used. The direction of the stripe pattern depends on the shape of the distance measuring sensor described later.

  Further, the focal length information, the shortest focusing distance information, the farthest focusing distance information, the current distance information, and the like of the photographing lens 1 are obtained via the lens information obtaining unit 21 and sent to the CPU 11. Based on the lens information, the CPU 11 instructs the auxiliary light projection unit 15 on the projection magnification of the focus detection pattern 20. The auxiliary light projection means 15 sets a focus detection pattern 20 with a predetermined magnification toward the subject based on an instruction from the CPU 11 and projects the focus detection pattern 20 toward the subject.

  The reflected light of the projected focus detection pattern 20 is incident on the focus detection means 9 via the photographing lens 1, the main mirror 3, and the sub mirror 7, and the focus detection is performed by the distance measuring sensor provided in the focus detection means 9. . In the automatic focus adjustment, after the focus shift of the subject is detected by the focus detection means 9, a lens driving device (not shown) is controlled via the CUP 11, and the focus adjustment is performed. After focusing is performed based on a signal from the focus detection means 9, the main mirror 3 is flipped up, the shutter 17 is operated, and a subject image is formed on the CCD 19. In this way, an autofocus camera equipped with the auxiliary light projection apparatus A is configured.

  The determination unit 13 may be provided on the camera side. Further, the auxiliary light projection device A may be built in the autofocus camera, or may be disposed outside the autofocus camera, for example, integrally with an external flash. Alternatively, it may be arranged at a position away from the camera as being communicable with the camera.

  FIG. 2 schematically shows the positional relationship between the focus detection pattern 20 in the finder 23 and a plurality of AF areas 25 (13 × 9 = 117 locations in the case of the present embodiment) arranged in the focus detection means 9. (AF area 25 is not visible to the photographer). In an autofocus camera having a plurality of AF areas 25, various focus detection methods are performed. Among these, a method of performing focus detection using a plurality of AF areas selected from the plurality of AF areas 25 will be described, but the same applies to other methods. FIG. 2 shows a case where focus detection is performed in four selected AF areas 25a, 25b, 25c, and 25d among 117 AF areas 25. Note that the number and location of AF areas to be selected can be arbitrarily specified by the photographer, or can be automatically set by information built in the autofocus camera. Further, the AF area 25 may be selected and used as a group, or may be selected and used individually.

  When the photographer selects four AF areas 25a to 25d, the CPU 11 uses the information on the photographing lens 1 from the lens information obtaining unit 21 and the information on the focus detection pattern 20 from the auxiliary light projection device A. It is determined whether or not the selected AF areas 25a to 25d exist in the focus detection pattern 20 projected on a subject (not shown). As shown in FIG. 2A, when a part (for example, 25a and 25b) of the selected AF areas 25a to 25d is out of the focus detection pattern 20, as shown in FIG. In addition, the focus detection pattern 20 is changed to an alternative AF area (for example, 25a ′, 25b ′) in the area irradiated with the focus detection pattern 20 in the vicinity of the selected AF areas 25a to 25d so that the focus detection can be performed reliably. .

  At this time, the alternative AF areas 25a ′ and 25b ′ selected in place of the AF areas 25a and 25b deviated from the focus detection pattern 20 are the rows, columns, or columns of the AF areas 25a and 25b previously deselected. The position is changed to the position where the focus detection pattern 20 is irradiated in the AF area located closest to the diagonal AF areas. FIGS. 2A and 2B show the case where the alternative AF area is reset in the column direction, and FIGS. 3A and 3B show the case where the row direction alternative AF area is reset. FIG. (B) exemplarily shows cases where alternative AF areas are reset in the row direction, the column direction, and the diagonal direction. In the case of FIG. 4, AF areas 25a, 25b, and 25d that are out of focus detection pattern 20 are reset to alternative AF areas 25a ', 25b', and 25d ', respectively.

  Next, the operation of the autofocus camera according to the present embodiment will be described using the operation flow shown in FIG. It is assumed that the AF area has been selected in advance by the photographer.

(Step S1)
Pressing a release (not shown) halfway starts automatic focusing on the subject.

(Step S2)
The CPU 11 receives lens information such as focal length information from the photographing lens 1 via the lens information acquisition unit 21.

(Step S3)
The CPU 11 receives information related to the irradiation range of the focus detection pattern 20 from the auxiliary light projection unit 15 of the auxiliary light projection apparatus A mounted on or attached to the autofocus camera.

(Step S4)
Based on the information from the photographing lens 1 and the information from the auxiliary light projection means 15, the CPU 11 focuses the AF area selected from the AF areas mounted on the autofocus camera from the auxiliary light projection means 15. It is determined whether it is set within the area of the detection pattern 20. If all the selected AF areas are within the irradiation range of the focus detection pattern 20 as a result of the determination, the selected AF area is part of the irradiation range of the focus detection pattern 20 in step S5. The process proceeds to step S6.

(Step S5)
Since the selected AF area is within the irradiation range of the focus detection pattern 20 to be projected, it is decided to use the selected AF area.

(Step S6)
Since part or all of the selected AF area is out of the irradiation range of the focus detection pattern 20 to be projected, the AF area outside the projection range of the focus detection pattern 20 is changed to an alternative AF area according to the above description. To determine the AF area for automatic focus detection.

(Step S7)
The focus detection pattern 20 is emitted from the auxiliary light projection apparatus A toward the subject.

(Step S8)
Focus detection is performed in the selected AF area, and the photographing lens 1 is driven by a lens driving unit (not shown) until the selected AF area is focused on the subject, and when the subject is focused, the focus is displayed to the photographer. Warning with etc. The photographer who has confirmed the warning presses the release fully to photograph the subject, and the series of operations ends.

  As described above, according to the autofocus camera of the present embodiment, based on the information from the auxiliary light projection apparatus A and the photographing lens 1, the individual or selected individual AF areas selected from the plurality of AF areas mounted on the autofocus camera. It is determined whether the grouped AF area is within the irradiation region of the focus detection pattern 20 projected from the auxiliary light projection apparatus A. When a part or all of the selected AF area deviates from the irradiation area of the focus detection pattern 20, it is ensured by changing the deviated AF area to an alternative AF area of the area irradiated with the focus detection pattern 20. Focus detection is possible. As a result, even when the photographing lens of the autofocus camera is replaced or when the auxiliary light projection device is replaced, the AF area selected as the irradiation area of the focus detection pattern 20 irradiated with the respective information received by the CPU and An alternative AF area can be set, and reliable focus detection is possible.

  In the present embodiment, an alternative AF area is set for an AF area that is out of the irradiation area of the focus detection pattern 20, but a warning is issued to the photographer without setting the alternative AF area. Alternatively, the alternative candidate AF area may be displayed so that the photographer can change the AF area.

  Further, instead of resetting the removed AF area (for example, 25a, 25b) as the alternative AF area, the AF area is made smaller than the AF area (for example, 25c, 25d) that does not contribute to the focus detection operation. You may do it.

  Further, instead of resetting the removed AF areas (for example, 25a and 25b) as alternative AF areas, the AF areas may be disabled during the focus detection operation.

  The autofocus camera is not limited to a digital camera using an image sensor such as a CCD, but may be a silver salt film camera or the like.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

1 is a schematic configuration diagram in which an auxiliary light projection device is mounted on an autofocus camera according to the present invention. FIG. It is an example of the positional relationship between the projected focus detection pattern and the AF area in the finder, (a) shows a case where a part of the selected AF area is out of the focus detection pattern, and (b) shows (a ) Shows a case where the alternative AF area is reset in the column direction instead of the AF area which has been removed. FIG. 10 is another example of the positional relationship between the projected focus detection pattern and the AF area in the finder, where (a) shows a case where a part of the selected AF area is out of the focus detection pattern, and (b) shows A case where the row direction alternative AF area is reset in place of the AF area removed in (a) is shown. FIG. 10 is another example of the positional relationship between the projected focus detection pattern and the AF area in the finder, where (a) shows a case where a part of the selected AF area is out of the focus detection pattern, and (b) shows In the example shown in (a), the alternative AF area is reset in the row direction, the column direction, and the diagonal direction instead of the out-of-focus area. It is a flowchart explaining embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens 3 Main mirror 7 Sub mirror 9 Focus detection means 11 CPU
DESCRIPTION OF SYMBOLS 13 Determination means 15 Auxiliary light projection means 17 Shutter 19 CCD (imaging element)
20 Focus detection pattern 21 Lens information acquisition means 23 Viewfinder 25 AF area 25a, 25b, 25c, 25d Selected AF area 25a ', 25b', 25d 'Alternative AF area

Claims (12)

An auxiliary light projection device for projecting a focus detection pattern onto a subject; and focus detection means for detecting a focus using reflected light of the focus detection pattern for at least one of a plurality of focus detection regions. In an automatic focusing camera that adjusts the focus based on the focus detection result of the means,
At least one focus detection for performing focus detection from the plurality of focus detection regions based on information from a photographing lens mounted on the camera and information from an auxiliary light projection device that projects the focus detection pattern Comprising a control means for selecting an area;
When the control unit determines that the position of the focus detection area selected in advance deviates from the position where the focus detection pattern is projected, the control means moves the selected focus detection area in the vicinity of the selected focus detection area. And the focus detection area corresponding to the position on which the focus detection pattern is projected.   2. The autofocus camera according to claim 1, wherein information from the auxiliary light projection device is communicated to the control means.   The autofocus camera according to claim 1, wherein the auxiliary light projection device sets a projection magnification of the focus detection pattern based on information from the photographing lens.   3. The autofocus camera according to claim 1, wherein the information from the auxiliary light projection device is information on at least an irradiation range of the focus detection pattern. 4.   On the basis of information from the photographing lens and information from the auxiliary light projection device, the control means deviates the preselected focus detection area from the focus detection pattern area on the camera finder. 5 or 4, the focus detection pattern is changed to a position where the focus detection pattern is projected in the focal distance detection region located closest to the preselected focus detection region. Autofocus camera as described in. The focus detection unit sets a plurality of the focus detection areas as a group of the focus detection target,
When the position of at least one focus detection area of the focus detection area in the group deviates from the position where the focus detection pattern is projected, the control means moves the defocused focus detection area in the vicinity of the group. 6. The autofocus camera according to claim 1, wherein the focus detection area is changed to a position where the focus detection pattern is projected. 7. An auxiliary light projection device for projecting a focus detection pattern onto a subject; and focus detection means for detecting a focus using reflected light of the focus detection pattern for at least one of a plurality of focus detection regions. In an automatic focusing camera that adjusts the focus based on the focus detection result of the means,
At least one focus detection for performing focus detection from the plurality of focus detection regions based on information from a photographing lens mounted on the camera and information from an auxiliary light projection device that projects the focus detection pattern Comprising a control means for selecting an area;
The focus detection unit sets a plurality of the focus detection areas as a group of the focus detection target,
When the position of at least one focus detection area of the focus detection area in the group deviates from the position where the focus detection pattern is projected, the control means moves the defocused focus detection area in the vicinity of the group. And an autofocus camera that changes to the focus detection area at a position where the focus detection pattern is projected.   8. The autofocus camera according to claim 7, wherein information from the auxiliary light projection device is communicated to the control means.   The autofocus camera according to claim 7 or 8, wherein the auxiliary light projection device sets a projection magnification of the focus detection pattern based on information from the photographing lens.   9. The autofocus camera according to claim 7, wherein the information from the auxiliary light projection device is information on at least an irradiation range of the focus detection pattern. 10.   On the basis of information from the photographing lens and information from the auxiliary light projection device, the control means deviates the preselected focus detection area from the focus detection pattern area on the camera finder. When it is judged that it is, it changes to the position where the pattern for focus detection is projected in the focal distance detection area located nearest to the pre-selected focus detection area. Autofocus camera as described in.   When the control unit determines that the position of the focus detection area selected in advance deviates from the position where the focus detection pattern is projected, the control means moves the selected focus detection area in the vicinity of the selected focus detection area. The automatic focus camera according to claim 11, wherein the focus detection area is changed to a position corresponding to a position where the focus detection pattern is projected.

Images