JP2008170782A - Auxiliary light pattern projection device, camera, and camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To project an auxiliary light pattern for focusing on an object. <P>SOLUTION: An auxiliary light projection part 302 includes a telephoto lens projection member projecting the auxiliary light pattern for focusing on the object at a prescribed magnification and a wide-angle lens projection member projecting the auxiliary light pattern for focusing on the object at a projection magnification higher than that of the telephoto lens projection member. A changeover part 303 changes over the wide-angle lens projection member and the telephoto lens projection member in accordance with a focal length of a lens 200 obtained through a hot shoe 108. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an auxiliary light pattern projection apparatus for projecting an auxiliary light pattern for focus detection onto a subject, a camera equipped with the same, and a camera system using the same.

  The following auxiliary light projection apparatus is known. This auxiliary light projection device changes the projection magnification of the focus detection pattern based on the focal length information obtained from the photographing lens (for example, Patent Document 1).

JP 2005-17746 A

  However, according to the conventional auxiliary light projection apparatus, a drive mechanism for zooming up or down the lens is provided in order to change the projection magnification of the focus detection pattern. For this reason, it takes time to drive the lens, and it takes time to change the projection magnification of the focus detection pattern.

The auxiliary light pattern projecting apparatus according to the present invention is provided separately from the first projecting unit and the first projecting unit that project the auxiliary light pattern for focus detection onto the subject at a predetermined projection magnification. A second projection unit that projects an auxiliary light pattern for focus detection onto a subject at a higher projection magnification than the first projection unit, and a first projection unit and a second projection unit according to the focal length of the photographing optical system, And switching means for switching between.
The camera by this invention mounts the auxiliary light pattern projector as described in any one of Claims 1-8.
The camera system according to the present invention includes a photographing lens, a camera to which the photographing lens can be attached and detached, and a flash device that can be attached to and detached from the camera. The photographing lens has storage means for storing lens information including a focal length, and lens information. A camera-side input means for inputting lens information, and a camera-side output means for outputting instruction information based on the lens information to the flash device. Is provided separately from the first projection means for projecting the focus detection auxiliary light pattern onto the subject at a predetermined projection magnification, and a projection magnification higher than that of the first projection means. Based on the instruction information, second projection means for projecting the auxiliary light pattern for focus detection onto the subject, flash device side input means for inputting the instruction information output from the camera side output means, and Characterized in that it comprises a switching means for switching the first projection means and the second projection means.

  According to the present invention, the projection magnification of the focus detection pattern can be switched at high speed.

  FIG. 1 is a block diagram showing a configuration of an embodiment of a camera system in which an auxiliary light pattern projection apparatus according to the present embodiment is connected to a camera body. The camera body (electronic camera) 100 is, for example, a single-lens reflex camera to which a lens 200 that is a photographing optical system is detachable, and includes a quick turn mirror 101, a sub mirror 102, a shutter 103, an image sensor 104, a lens mount unit 105, and focus detection. Unit 106, CPU 107, and hot shoe 108.

  The lens 200 can be attached (detachable) to the camera body 100 via the lens mount unit 105, and a telephoto lens, a wide-angle lens, or the like can be selectively attached thereto. The auxiliary light pattern projection device 300 is, for example, an external flash device, and is connected to the camera body 100 via the hot shoe 108. The auxiliary light pattern projection device (flash light generation device, strobe device) 300 includes a light emitting unit 301 that emits flash light for subject illumination during shooting, an auxiliary light projection unit 302 provided separately from the light emitting unit 301, and a switching unit. Part 303 is provided.

  In the camera body 100, the light of the subject incident through the lens 200 is divided into a finder system and a focus detection system (not shown) in the main mirror 101. The light to the focus detection system passes through the main mirror 101, is reflected by the sub mirror 102, and enters the focus detection unit 106. The focus detection unit 106 automatically performs focus detection based on the incident subject light and performs focus adjustment. That is, as will be described later, the focus detection unit 106 detects the auxiliary light pattern projected onto the subject from the auxiliary light pattern projection device 300, and automatically performs focus adjustment using a known phase difference detection method, for example.

  When a release button (not shown) is pressed by the user, the CPU 107 retracts the main mirror 101 and the sub mirror 102 from the photographing optical path and opens the shutter 103. As a result, the subject image formed by the lens 200 can be captured by the image sensor 104, for example, a CCD or CMOS, and an image can be acquired. Further, the lens mount unit 105 is provided with a contact 105a that can be electrically connected to the contact unit 200a provided on the lens 200 side, and information on the lens from the mounted lens 200 through the contact 105a. For example, information on focal length is acquired and output to the CPU 107.

  In the camera main body 100 according to the present embodiment, the CPU 107 outputs instruction information to the auxiliary light pattern projector 300 connected via the hot shoe 108 in order to perform automatic focus adjustment by the focus detection unit 106. To instruct the projection of the auxiliary light pattern for focus detection. At this time, the CPU 107 outputs information (including focal length information) about the lens 200 acquired by the lens mount unit 105 to the auxiliary light pattern projector 300.

  The switching unit 303 of the auxiliary light pattern projector 300 is mounted on the camera main body 100 based on information about the lens 200 received from the CPU 107 when an instruction to project an auxiliary light pattern is received from the CPU 107 of the camera main body 100. The focal length of the lens 200 is determined. Then, the auxiliary light pattern projected on the subject is switched by the auxiliary light pattern projection unit 302 according to the focal length of the lens 200. Hereinafter, switching of the auxiliary light pattern will be described in detail.

  The auxiliary light pattern projection unit 302 includes two sets of projection members having different projection magnifications of the auxiliary light pattern. Each projection member includes a light source, a lens group that is a projection optical system, and a prism that divides light emitted from the light source into a predetermined auxiliary light pattern. For example, the projection member for a wide-angle lens for projecting an auxiliary light pattern for focus detection onto a subject at a predetermined projection magnification shown in FIG. 2A and the projection member for a wide-angle lens shown in FIG. A telephoto lens projection member for projecting an auxiliary light pattern for focus detection onto a subject at a projection magnification. As the light source, for example, an LED is used. In the present embodiment, the same type of LED is used for the LED used for the wide-angle lens projection member and the LED used for the telephoto lens projection member.

  As shown in FIG. 2A, the wide-angle lens projection member includes a light source (LED) 2a, a wide-angle projection lens group 2b, and a wide-angle lens auxiliary light pattern dividing prism 2c. As shown, the auxiliary light pattern enlarged by the wide-angle projection lens group 2b is projected onto the subject. As shown in FIG. 2B, the telephoto lens projection member includes a light source (LED) 2d, a telephoto projection lens group 2e, and a telephoto lens auxiliary light pattern dividing prism 2f. As shown, the auxiliary light pattern enlarged by the telephoto projection lens group 2e is projected onto the subject. As shown in FIG. 3, the auxiliary light pattern projected by the telephoto lens projection member is the same as the auxiliary light pattern projected by the wide-angle lens projection member (the original pattern before each projection is the same). The pattern itself projected onto the projection surface is smaller in size than the pattern projected in FIG. 2A.

  FIG. 4 is a diagram illustrating an arrangement example of the wide-angle lens projection member and the telephoto lens projection member when the auxiliary light pattern projection unit 302 is viewed from the front. As shown in FIG. 4, when the auxiliary light pattern projection unit 302 is viewed from the front (from the side facing the emission surface of the auxiliary light pattern), the wide-angle auxiliary light pattern dividing prism 2c of the wide-angle lens projection member is used. And the telescopic auxiliary light pattern dividing prism 2f of the telephoto lens projection member can be seen, and they are arranged side by side. The telephoto auxiliary light pattern dividing prism 2f is about 1.5 times larger than the wide-angle auxiliary light pattern dividing prism 2c.

  The switching unit 303 switches the projection member used for projecting the auxiliary light pattern onto the subject between the wide-angle lens projection member and the telephoto lens projection member in accordance with the focal length of the lens 200. For example, when the focal length of the lens 200 is less than a predetermined threshold, for example, less than 50 mm, the lens 200 is determined to be a wide-angle lens and switched to a wide-angle lens projection member. On the other hand, when the focal length of the lens 200 is the above-described predetermined threshold, for example, 50 mm or more, it is determined that the lens 200 is a telephoto lens and switched to a telephoto lens projection member. The threshold value used here may be a fixed value or may be arbitrarily changed by the user.

  Specifically, as illustrated in FIG. 5, the switching unit 303 performs switching by switching whether or not power is supplied to the light sources 2 a and 2 d. That is, when the focal length of the lens 200 is less than the predetermined threshold, the switch 5a is tilted toward the light source 2a to supply power to the light source 2a. Thereby, the light source 2a emits light, and the auxiliary light pattern can be projected onto the subject by the projection member for the wide angle lens. On the other hand, when the focal length of the lens 200 is greater than or equal to a predetermined threshold, the switch 5a is tilted toward the light source 2d to supply power to the light source 2d. As a result, the light source 2d emits light, and the auxiliary light pattern can be projected onto the subject by the telephoto lens projection member. In addition, the code | symbol 7a of FIG. 7 is mentioned later.

  As described above, when the focal length of the lens 200 is less than the predetermined threshold, the auxiliary light pattern is projected by the wide-angle lens projection member having a large auxiliary light pattern to be projected. When the focal length of the lens 200 is equal to or greater than a predetermined threshold, the auxiliary light pattern is projected by a telephoto lens projection member having a small auxiliary light pattern to be projected.

  As a result, when the focal length of the lens 200 is long, the image of the auxiliary light pattern projected on the subject is enlarged by the lens 200 and is incident on the focus detection surface of the focus detection unit 106. Therefore, a small auxiliary light pattern is formed. If projected onto the subject, an auxiliary light pattern having a size necessary for the focus detection unit 106 to perform focus detection can enter the focus detection unit 106. On the other hand, when the focal length of the lens 200 is short, the image of the auxiliary light pattern projected onto the subject is incident on the focus detection surface without being enlarged as much as the telephoto lens. When projected onto the focus detection unit 106, an auxiliary light pattern having a size necessary for the focus detection unit 106 to perform focus detection can be incident on the focus detection unit 106.

  FIG. 6 is a flowchart showing the processing of the auxiliary light pattern projection apparatus 300 in the present embodiment. The processing shown in FIG. 6 is executed by the switching unit 303 as a program that is activated when the auxiliary light pattern projection apparatus 300 is connected to the camera body 100 via the hot shoe 108.

  In step S <b> 10, it is determined whether or not there is an auxiliary light pattern projection instruction from the CPU 107 of the camera body 100 via the hot shoe 108. When an affirmative determination is made, the process proceeds to step S20, and it is determined whether or not the focal length of the lens 200 is less than a predetermined threshold, for example, less than 50 mm. If the determination is affirmative, the process proceeds to step S30, and as described above with reference to FIG. 5, the switch 5a is tilted toward the light source 2a to start energization, and the auxiliary light pattern is projected by switching to the wide-angle lens projection member. On the other hand, if a negative determination is made, the process proceeds to step S40, the switch 5a is turned to the light source 2d side to start energization, and the auxiliary light pattern is projected by switching to the telephoto lens projection member. Thereafter, the process ends.

According to the present embodiment described above, the following operational effects can be obtained.
(1) A telephoto lens projection member that projects a focus detection auxiliary light pattern onto a subject at a predetermined projection magnification, and a focus detection auxiliary light pattern onto the subject at a higher projection magnification than the telephoto lens projection member. And a projection member for a wide-angle lens. The switching unit 303 switches between the wide-angle lens projection member and the telephoto lens projection member in accordance with the focal length of the lens 200 that is the photographing optical system. Accordingly, it is possible to switch to an appropriate projection member according to the focal length of the lens 200.

(2) The auxiliary light patterns projected by the wide-angle lens projection member and the telephoto lens projection member have the same pattern. Accordingly, the focus detection unit 106 can perform focus detection with high accuracy even when the auxiliary light pattern is projected by either the wide-angle lens projection member or the telephoto lens projection member.

(3) The switching unit 303 performs switching to the wide-angle lens projection member when the focal length of the lens 200 is less than a predetermined threshold, and when the focal length of the lens 200 is equal to or greater than the predetermined threshold. Switching to a telephoto lens projection member was performed. Accordingly, when the focal length of the lens 200 is long, the image of the auxiliary light pattern projected onto the subject is enlarged and incident. Therefore, if a small auxiliary light pattern is projected, the focus detection unit 106 performs focus detection. Therefore, an auxiliary light pattern having a size necessary for this can be incident on the focus detection unit 106. On the other hand, when the focal length of the lens 200 is short, the image of the auxiliary light pattern projected on the subject is incident without being enlarged as much as the telephoto lens. Therefore, if a large auxiliary light pattern is projected, the focus detection unit An auxiliary light pattern having a size necessary for the focus detection by the 106 can be incident on the focus detection unit 106.

(4) The predetermined threshold for determining the switching of the projection member can be changed. Thereby, the threshold value can be changed according to the user's preference, and convenience is improved.

(5) The switching unit 303 switches the projection member by switching the power supply to the light source included in the projection member for the wide-angle lens and the light source included in the projection member for the telephoto lens. Accordingly, the projection member can be switched with a simple configuration, which is advantageous in terms of cost. Also, the projection member can be switched at high speed.

-Modification-
The camera connected to the auxiliary light pattern projection apparatus of the above-described embodiment can be modified as follows.
(1) In the above-described embodiment, an example in which the same type of LED is used for the LED used for the wide-angle lens projection member and the LED used for the telephoto lens projection member has been described. However, different types of LEDs may be used. For example, a brighter LED than the telephoto lens projection member may be used for the wide-angle lens projection member. As a result, the auxiliary light pattern projected by the wide-angle lens projection member is larger than the auxiliary light pattern projected by the telephoto lens projection member as shown in FIG. A simple auxiliary light pattern can be projected,

(2) In the above-described embodiment, the case where the auxiliary light pattern projected by the telephoto lens projection member and the auxiliary light pattern projected by the wide-angle lens projection member are the same has been described. However, they may be different patterns (optimal patterns for each projection system).

(3) In the above-described embodiment, the switching unit 303 has described an example in which the projection member is switched by determining whether the focal length of the lens 200 is less than a predetermined threshold. However, when it is possible to determine whether the lens 200 to which the lens mount unit 105 is attached is a wide-angle lens or a telephoto lens and output the information, the switching unit 303 determines whether the lens 200 is a wide-angle lens or a telephoto lens. Switching may be performed based on the determination result. That is, when determining that the lens 200 is a wide-angle lens, the switching unit 303 switches to the wide-angle lens projection member and projects the auxiliary light pattern. On the other hand, when it is determined that the lens 200 is a telephoto lens, the auxiliary light pattern is projected by switching to the telephoto lens projection member.

(4) In the above-described embodiment, the switching unit 303 has been described with respect to the example in which the projection member is switched based on the focal length of the lens 200. However, the switching unit 303 may switch the projection member in consideration of at least one of the zoom ratio of the photographing optical system and the distance from the photographing optical system to the subject. For example, when the distance to the subject is taken into account, if the distance to the subject is long, there is a high possibility of shooting using a telephoto lens. Therefore, for the telephoto lens to reduce the auxiliary light pattern projected onto the subject Switch to the projection member. On the other hand, if the distance to the subject is short, there is a high possibility of shooting using a wide-angle lens. Therefore, if the auxiliary light pattern to be projected onto the subject is enlarged, switching to a projection member for wide-angle lens is possible. Good.

(5) In the embodiment described above, the switching unit 303 switches the projection member based on the focal length of the lens 200, and the focus detection unit 106 detects the auxiliary light pattern projected by the switched projection member. The example of performing the focus adjustment has been described. However, the switching unit 303 may switch the projection member based on the focal length of the lens 200 to project the auxiliary light pattern, and then switch to the other projection member and project the auxiliary light pattern again. Good. Then, the focus detection unit 106 performs focus detection each time each auxiliary light pattern is projected onto the subject, compares the focus detection results obtained each time, and has a better detection result (for example, the defocus amount). The focus detection may be performed using the detection result of the smaller one. In addition, a projection member having a good detection result at that time may be set to be used as a projection member under the photographing conditions (lens focal length, subject distance, zoom ratio, etc.).

  Alternatively, the focus detection unit 106 first detects the auxiliary light pattern projected and performs the focus adjustment, and then detects the auxiliary light pattern projected later and performs the focus adjustment. The accuracy (focus adjustment accuracy) is output to the switching unit 303. The switching unit 303 may detect the focus adjustment accuracy input from the focus detection unit 106 and perform switching to the projection member with the higher focus adjustment accuracy.

(6) In the above-described embodiment, the auxiliary light pattern projection unit 302 includes the wide-angle lens projection member and the telephoto lens projection member as the projection members, and the switching unit 303 has 2 depending on the focal length of the lens 200. The example which switches to any one of the members of the set has been described. However, the auxiliary light pattern projection unit 302 may include three or more projection members. For example, the projection member may include three sets of projection members: a wide-angle lens projection member, a standard lens projection member, and a telephoto lens projection member. Then, for example, the switching unit 303 switches to a wide-angle lens projection member if the focal length of the lens 200 is less than 40 mm, switches to a standard lens projection member if it is 40 mm or more and less than 70 mm, and telephoto if it is 70 mm or more. You may make it switch to the projection member for lenses.

  In this case, as shown in FIG. 7, the switching unit 303 determines whether or not power is supplied to the light source 2a of the projection member for wide-angle lens, the light source 7a of the projection member for standard lens, and the light source 2d of the projection member for telephoto lens. Switch. That is, when the focal length of the lens 200 is less than the predetermined 40 mm, the switch 5a is tilted toward the light source 2a to supply power to the light source 2a. If the distance is 40 mm or more and less than 70 mm, the switch 5a is tilted toward the light source 7a to supply power to the light source 7a. On the other hand, when the focal length of the lens 200 is 70 mm or more, the switch 5a is tilted toward the light source 2d to supply power to the light source 2d.

(7) In the above-described embodiment, the auxiliary light pattern projecting device 300 is an external flash device and has been described as being connected to the camera body 100 via the hot shoe 109. However, the auxiliary light pattern projection device 300 may be a flash device built in (mounted on) the camera body 100. That is, in FIG. 1, the camera body 100 and the auxiliary light pattern projection device 300 may be integrated. Further, as the auxiliary light pattern projection apparatus 300, a projection apparatus having only a function of irradiating a subject with an auxiliary light pattern for focus detection may be used without using a flash device. That is, in FIG. 1, the auxiliary light pattern projection device 300 may not include the light emitting unit 301.

(8) In the above-described embodiment, an example in which the camera body 100 is a single-lens reflex camera to which the lens 200 that is a photographing optical system is detachable has been described. However, it may be a camera with a built-in lens, for example, a compact camera. That is, in FIG. 1, the camera body 100 and the lens 200 may be integrated.

  Note that the present invention is not limited to the configurations in the above-described embodiments as long as the characteristic functions of the present invention are not impaired.

It is a block diagram which shows the structure of one Embodiment of the camera system which connected the auxiliary light pattern projector. It is a figure which shows the specific example of a projection member. It is a figure which shows the specific example of the auxiliary light pattern projected. It is a figure which shows the example of arrangement | positioning of the projection member for wide angle lenses, and the projection member for telephoto lenses when the auxiliary light pattern projection part 302 is seen from the front. It is a 1st figure which shows the example of a switching of the electric power supply to a light source. FIG. 10 is a flowchart showing processing of the auxiliary light pattern projector 300. It is a 2nd figure which shows the example of switching of the electric power supply to a light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Camera, 101 Quick turn mirror, 102 Sub mirror, 103 Shutter, 104 Image sensor, 105 Lens mount part, 106 Focus detection part, 107 CPU, 108 Hot shoe, 200 Lens, 300 Auxiliary light pattern projector, 301 Light emission part, 302 Auxiliary light projection unit, 303 switching unit

Claims (10)

First projection means for projecting an auxiliary light pattern for focus detection onto a subject at a predetermined projection magnification;
A second projection unit that is provided separately from the first projection unit and projects an auxiliary light pattern for focus detection onto a subject at a projection magnification higher than that of the first projection unit;
An auxiliary light pattern projecting apparatus comprising: a switching unit that switches between the first projecting unit and the second projecting unit according to a focal length of a photographing optical system. The auxiliary light pattern projector according to claim 1,
The auxiliary light pattern projected by the first projecting unit and the auxiliary light pattern projected by the second projecting unit are the same before photographing, the pattern being the same Pattern projection device. In the auxiliary light pattern projector according to claim 1 or 2,
When the focal length of the photographing optical system is less than a predetermined threshold, the switching means switches to the second projecting means, and the focal length of the photographing optical system is equal to or larger than a predetermined threshold. The auxiliary light pattern projecting apparatus is characterized by switching to the first projecting means. In the auxiliary light pattern projector according to claim 3,
The auxiliary light pattern projector according to claim 1, wherein the predetermined threshold value can be changed. In the auxiliary light pattern projector according to any one of claims 1 to 4,
The auxiliary light pattern projector according to claim 1, wherein the switching unit switches the projection unit in consideration of at least one of a zoom ratio of the photographing optical system and a distance from the photographing optical system to the subject. In the auxiliary light pattern projector according to any one of claims 1 to 5,
The switching means switches the projection means by switching the presence or absence of power supply to the light source provided in the first projection means and the light source provided in the second projection means. Pattern projection device. In the auxiliary light pattern projector according to any one of claims 1 to 6,
A focus detection means for detecting a focus by detecting the auxiliary light pattern for focus detection projected on the subject;
The focus detection auxiliary light pattern projected by the first projection unit and the focus detection auxiliary light pattern projected by the second projection unit and the focus detection result. A comparison means for comparing the result detected by the detection means;
The auxiliary light pattern projecting apparatus according to claim 1, wherein the switching unit performs switching to the projection unit that has obtained a better focus detection state as a result of the comparison by the comparison unit. In the auxiliary light pattern projector according to any one of claims 1 to 7,
The photographing optical system is an interchangeable lens that can be attached to and detached from a camera.
Based on the focal length of the imaging optical system, further comprising a determination means for determining whether the imaging optical system mounted on the camera is a wide-angle lens or a telephoto lens;
The switching means switches to the second projection means when the determining means determines that the photographing optical system is a wide-angle lens, and determines that the photographing optical system is a telephoto lens. In the case of an auxiliary light pattern, the auxiliary light pattern projection apparatus switches to the first projection means.   A camera equipped with the auxiliary light pattern projection device according to claim 1. A camera system comprising a photographic lens, a camera to which the photographic lens can be attached and detached, and a flash device that can be attached to and detached from the camera,
The taking lens is
Storage means for storing lens information including focal length;
Lens side output means for outputting the lens information to the outside,
The camera
Camera side input means for inputting the lens information;
Camera side output means for outputting instruction information based on the lens information to the flash device;
The flash device is
First projection means for projecting an auxiliary light pattern for focus detection onto a subject at a predetermined projection magnification;
A second projection unit that is provided separately from the first projection unit and projects an auxiliary light pattern for focus detection onto a subject at a projection magnification higher than that of the first projection unit;
Flash device side input means for inputting the instruction information output from the camera side output means,
A camera system comprising switching means for switching between the first projection means and the second projection means based on the instruction information.

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