JP2005258030A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an AF camera which is able to appropriately irradiate an object with auxiliary light even in a case of short distance photography. <P>SOLUTION: The camera 10 is provided with a photographic lens 12, and an AF auxiliary light source 14, and a release button 16. As shown in the figure, an irradiation angle of the AF auxiliary light source 14 can be changed by an unshown driving means. The AF auxiliary light can be used effectively by changing an angle of the AF auxiliary light source 14 so that the object 18b at a short distance is correctly irradiated with the light. Auto-focusing can be controlled so as to operate more properly by defining the optical axis of the AF auxiliary light source as La2 and shifting a point of intersection C2 at the optical axis Lb of the photographic lens 12 to the position of the object 18b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a camera, and more particularly to an AF camera that automatically adjusts the focal length of a photographic lens using auxiliary light.

  In recent years, so-called AF (autofocus), in which focusing is automatically performed in a digital video camera or digital camera, more than a normal silver salt camera, has become an extremely important and naturally necessary function.

  However, when the subject brightness level is low and contrast cannot be obtained such as at night or indoors, so-called passive AF such as a phase detection method may not work properly. Therefore, there is an AF that includes an AF auxiliary light source in the camera, and improves the focusing accuracy in a dark place by irradiation light from the auxiliary light source.

  By the way, in the conventional AF using the auxiliary light, as described above, light is emitted when it is determined that the luminance level of the subject is low and the AF does not reach an appropriate value. However, the light emission is unique and cannot be applied. . That is, light is always emitted in the same direction and intensity regardless of the distance to the subject.

  As a camera in which a so-called viewfinder parallax is generated between the viewfinder and the photographing optical system, a camera capable of measuring a distance without being influenced by the viewfinder parallax by arranging a plurality of AF auxiliary lights has been proposed (for example, Patent Documents). 1).

  However, for example, the AF auxiliary light is not efficiently irradiated to the subject in the close-up shooting, that is, in the close-up shooting, the AF does not work properly because the subject is near the point where the optical axis of the AF auxiliary light coincides with the optical axis of the photographing lens. It is not a solution to the potential problem.

That is, as shown in FIG. 3, since the AF auxiliary light source 100 is fixed, if the subject 102 is near the point c where the optical axis La of the AF auxiliary light and the optical axis Lb of the photographing lens 104 coincide, the subject 102 In contrast, the AF auxiliary light is not efficiently irradiated.
Japanese Patent Laid-Open No. 8-86955

  In consideration of the above facts, an object of the present invention is to provide an AF camera in which auxiliary light is appropriately irradiated to a subject even in close-up photography.

  The camera according to claim 1 includes an imaging optical system and a distance measuring unit using AF auxiliary light, and the optical axis of the AF auxiliary light is movable with respect to the optical axis of the imaging optical system. Features.

  In the invention with the above configuration, the AF auxiliary light is moved so that the point at which the optical axis of the AF auxiliary light coincides with the optical axis of the photographing optical system is adjusted to the distance to the subject, so that the AF can be operated more appropriately. Can be controlled.

  The camera according to claim 2 calculates a distance to the subject based on a reflected light amount of the AF auxiliary light reflected from the subject, and when the distance to the subject is equal to or less than a predetermined value, the optical axis of the AF auxiliary light is calculated. Is moved so that the point where the optical axis of the photographing optical system and the optical axis of the AF auxiliary light intersect with each other approaches the camera.

  In the invention with the above configuration, if the distance to the subject calculated by the amount of reflected light from the subject is short, it is determined that close-up shooting is performed, and the AF auxiliary light is shifted to the close-up shooting for efficient shooting of the AF auxiliary light to the subject. Irradiation can be performed to control AF more appropriately.

  Since the present invention has the above-described configuration, an AF camera that appropriately radiates auxiliary light to the subject can be obtained even in close-up photography.

  FIG. 1 shows a camera according to a first embodiment of the present invention.

  As shown in FIG. 1, the camera 10 includes a photographing lens 12, an AF auxiliary light source 14, and a release button 16.

  The AF auxiliary light source 14 can change the irradiation angle as shown in the figure by driving means (not shown). During normal photographing, the AF auxiliary light source 14 irradiates the farthest distance, that is, operates at an angle at which the intersection C1 where the optical axis La1 intersects the optical axis La of the photographing lens 12 is farthest from the camera 10.

  In normal shooting, the subject 18a is near or far from the intersection C1 of the optical axis Lb of the taking lens 10 and the optical axis La1 of the AF auxiliary light, so that the AF auxiliary light is correctly irradiated and AF works properly, or Since the shooting distance is large, high focusing accuracy is not required, so no problem occurs during shooting.

  However, since the position of the subject 18b is close to the camera 10 when close-up or copying, or when photographing itself, the optical axis La1 of the AF auxiliary light deviates from the subject 18b, and the AF auxiliary light is not correctly irradiated. For this reason, the AF may not operate properly.

  Here, the AF auxiliary light can be effectively used by changing the angle of the AF auxiliary light source 14 so that the subject 18b at a short distance is correctly irradiated.

  That is, by setting the optical axis of the AF auxiliary light to La2, the intersection C2 with the optical axis Lb of the photographic lens 12 can be moved to the position of the subject 18b, and control can be performed so that AF is more appropriately performed.

  FIG. 2 is a block diagram of the camera according to the first embodiment of the present invention.

  As shown in FIG. 2, the camera 10 includes an imaging unit 20 including a lens 12 and an imaging device, a control unit 22 that controls the imaging unit 20, an AF auxiliary light source 14, a recording unit 24, a release button 16, and an operation unit 26. It is made up of.

  The imaging unit 20 converts image information according to the control of the control unit 22 into an electrical signal. The control unit 22 records and reproduces image information sent from the imaging unit 20 through the recording unit 24, and sends control information such as AE (automatic exposure), AF (automatic focus), and AWB (automatic white balance) to the imaging unit 20. introduce.

  The AF auxiliary light source 14 moves according to control from the control unit 22 and emits light as necessary. The recording unit 24 records the image information from the control unit 20 on a recording medium such as a memory or a card medium. The operation unit 26 transmits information such as a release operation to the control unit 22 when operated by the user.

  In normal shooting, the AF auxiliary light is emitted when the release button 16 is half-pressed (S1) and is extinguished when the release button 16 is fully pressed (S2). However, for example, when the ambient luminance level measured by a photometric element for AE control or the like is a certain amount or less, the light may be emitted constantly.

  The angle control of the AF auxiliary light source 14 in FIG. 1 is performed in the following steps.

  That is, in S1, the angle of the AF auxiliary light source 14 is changed while measuring the amount of reflected AF auxiliary light from the subject 18 with, for example, the above-mentioned photometric element for AE control. It is determined that the intersection C between the optical axis La of the AF auxiliary light and the optical axis Lb of the photographing lens 12 overlaps the subject 18 when the amount of reflected light from the subject 18 becomes maximum.

  By performing distance measurement using the AF auxiliary light at this point, the optical axis La of the AF auxiliary light is directed to the surface of the subject 18, so that the AF auxiliary light is most effectively used to properly perform the AF. Can be controlled.

Further, by using the angle information of the AF auxiliary light source 14 at this time as basic information about the distance to the subject 18, the AF search range is narrowed down before the start of the AF operation, and the time required for the AF operation is shortened. It may be.

FIG. 1 is a plan view showing the camera according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration of the camera according to the first embodiment. FIG. 3 is a plan view showing a conventional camera.

Explanation of symbols

10 Camera 12 Shooting Lens 14 AF Auxiliary Light Source 16 Release Button 18 Subject

Claims (2)

Photographic optics,
Ranging means using AF auxiliary light,
A camera characterized in that an optical axis of the AF auxiliary light is movable with respect to an optical axis of the photographing optical system. Calculate the distance to the subject by the amount of reflected AF auxiliary light reflected from the subject,
When the distance to the subject is equal to or less than a specified value, the optical axis of the AF auxiliary light is moved so that the point where the optical axis of the photographing optical system intersects with the optical axis of the AF auxiliary light approaches the camera. The camera according to claim 1.

Images