JP2006154458A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To photograph a successful image even in macro photography in which distance with an object shows a few centimeter by solving a problem in which such macro photography has been conventionally performed by controlling light emission and diaphragm using a xenon tube at flash photography of a camera, however, it is hard to prevent overexposure at that time. <P>SOLUTION: The camera has a plurality of light sources 3, 4, 5, 6, 7, 8, 9, 10 of different kinds, in which the light sources 3, 4, 5, 6, 7, 8, 9, 10 are optionally switched by the distance with the object and controls light intensity of a flash so that appropriate exposure is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a camera capable of irradiating a subject with an appropriate amount of light by switching a light source when performing flash photography.

Many cameras on the market today have a built-in flash. The flash consists of a xenon tube, a reflector, a capacitor, and a circuit that controls the capacitor. First, the subject is dimmed, and an appropriate amount of light is calculated from conditions such as the zoom position and focus position to control light emission and The aperture is changed. A single xenon tube occupies the majority, but some have a plurality of strobe light emitting units and a plurality of xenon tubes (for example, see Patent Document 1) or a plurality of light emitting units having different color temperatures ( For example, see Patent Document 2).
JP 2002-14395 A JP-A-6-214292

  When macro photography is performed with the above camera, it is difficult to control the amount of light with a single xenon tube, and the aperture is limited, resulting in overexposure. On the other hand, if the amount of light is reduced, there may be a case where a sufficient amount of light cannot be obtained during normal shooting. Therefore, it is conceivable to use a plurality of light emitting units and a plurality of xenon tubes as in Patent Document 1 (the Patent Document 1 does not describe means for solving overexposure at the time of macro photography). Since only the xenon tube is used, the amount of light is too large compared to the LED, and it is difficult to prevent overexposure when used for macro photography where the distance to the subject is several centimeters. Further, the above-mentioned Patent Document 2 does not touch on macro photography.

  An object of the present invention is to provide a camera having a flash that can irradiate an appropriate amount of light at any of the above-described shooting distances and can prevent overexposure during macro shooting.

  In order to achieve the above-described object, according to the first aspect of the present invention, the camera has a plurality of types of different light sources, and the light sources can be arbitrarily switched according to the distance to the subject, and appropriate exposure can be performed. The light quantity of the flash can be controlled to obtain the above.

  According to the second aspect of the present invention, the amount of flash of the camera is adjusted by the type and number of light sources that emit light.

  According to a third aspect of the present invention, the light source of the flash of the camera is a xenon tube or LED.

  According to the fourth aspect of the present invention, the white balance can be controlled in accordance with a change in the type of light source in the flash of the camera.

  According to the invention of claim 5 of the present invention, Fresnel lenses having different condensing characteristics are provided in front of different types of light sources.

  According to the invention of claim 6 of the present invention, when a plurality of different types of light sources in the flash of the camera emit light at the same time, the number of emitted light is less than that of the plurality of light sources. The light source is controlled to emit light preferentially.

  According to the seventh aspect of the present invention, the LED that emits light in the flash of the camera is preferentially selected from those at a short distance from the photographing lens.

  According to the eighth aspect of the present invention, the LED in the flash of the camera can be used as auxiliary light used when performing AF control.

  According to the ninth aspect of the present invention, at least one LED of the camera can change the irradiation angle depending on the distance of the subject.

  According to the invention of claim 10 of the present invention, the plurality of LEDs are arranged concentrically around the imaging lens.

  According to the invention of claim 11 of the present invention, the camera has a plurality of types of different light sources and has a flash capable of controlling white balance in accordance with the color temperature of the light source that emits light. And

  According to the twelfth aspect of the present invention, the amount of light in the flash of the camera is adjusted by the type and number of light sources that emit light.

  According to the thirteenth aspect of the present invention, the light source that emits light is a xenon tube or an LED.

  According to the present invention, it is possible to obtain appropriate exposure without causing a captured image to be overexposed regardless of the distance to the subject.

  Moreover, it becomes possible to suppress power consumption lower by using LED than the case where only a xenon tube is used.

  Even when a flash light source having a different color temperature is used, appropriate correction is performed, and a high-quality image can be obtained.

  According to the invention according to the present application, it is possible to obtain appropriate exposure without causing the photographed image to fly out regardless of the distance to the subject.

  Moreover, it becomes possible to suppress power consumption lower by using LED than the case where only a xenon tube is used.

  Even when a flash light source having a different color temperature is used, appropriate correction is performed, and a high-quality image can be obtained.

  Examples of the present invention will be described below.

  Although this embodiment mode is described as applied to a digital camera, a camera having a flash such as a film camera or a video camera may be used.

  FIG. 1 is a schematic view of a camera according to the present invention. As shown in FIG. 1, 1 is a camera body, 2 is a photographic lens, 3 is auxiliary light for AF, 3, 4, 5, and 6 are LEDs, 7, 8, 9, and 10 are xenon tubes, and 11 is a Fresnel lens. Reference numerals a and 12 denote Fresnel lenses b, 13 an optical viewfinder window, 14 a shutter button, and 15 a camera power button.

  FIG. 2 shows a rear view of the camera. Reference numeral 16 is a liquid crystal display, 17 is an optical viewfinder, 18 is a flash switching button for switching between flash forced light emission, red-eye prevention light emission and light emission inhibition, and 19 is a normal shooting / macro shooting switching button. Other components are omitted. In addition to displaying the captured image, the 16 liquid crystal display displays a flash mode display, a normal shooting / macro mode, and other shooting modes so that the current settings can be seen.

  In FIG. 3 showing the configuration of the flash according to the present invention, 7, 8, 9, and 10 are xenon tubes, 3, 4, 5, and 6 are LEDs, 11 is a Fresnel lens a, 12 is a Fresnel lens b, and 20 is a reflector. Reference numeral 21 denotes a trigger circuit for sending a trigger signal to the xenon tube and a strobe circuit including a capacitor for causing the xenon tube to emit light. Reference numeral 22 denotes a circuit for controlling light emission of the LED and the xenon tube. The LEDs 3, 4, 5, and 6 are arranged in the horizontal direction toward the front of the camera, and the xenon tubes 7, 8, 9, and 10 are arranged in the vertical direction, and the number of light emitted by the control circuit can be changed.

  11 Fresnel lenses a are placed on the front of the LED to diffuse the LED light, and 12 Fresnel lenses b are placed on the front of the xenon tube to condense the light so that both light is irradiated to the angle of view. Is done. Thereby, it is possible to suppress the occurrence of luminance unevenness. Further, it is assumed that the LED that emits light is selected from the LEDs that are close to the photographing lens in order to prevent generation of shadows on the subject due to LED light emission during macro photography. For the xenon tube, the outer xenon tube away from the taking lens is preferentially selected to prevent red eyes.

  A block diagram showing the internal structure of the camera is shown in FIG. When the camera is turned on and the shutter button is pressed halfway, AF control, distance measurement, and photometry are performed. An image signal obtained by an imaging unit comprising 24 lenses, 25 shutters / apertures, 26 focus lenses, and 27 CCDs is processed by the imaging engine 28 and sent to the CPU 23.

  The CPU drives the focus lens 26 so that the contrast of the transmitted image is maximized, and determines the position where the contrast reaches the peak as the focus matching point. Information on the distance between the camera and the subject can be obtained from the focal length at the time of focusing. When performing AF control, the LED is used as auxiliary light, but the LEDs 3, 4, 5, and 6 used for the flash in the present invention can be used as AF auxiliary light.

  When it is determined that the flash emission is necessary based on the luminance information of the subject obtained by the imaging unit, the flash illumination luminance, aperture value, and exposure are set according to the distance to the subject and the luminance of the subject. Based on the set numerical value, the light emission control circuit determines the light emission number of the light emission number LED of the xenon tube. It is assumed that the white balance is set as needed depending on the number of the light emitting light sources and the number of the light emitting light sources. When the shutter button is then fully pressed, shooting is performed according to the set conditions. The white balance is determined in advance according to the number of light sources and the number of light sources, and is switched before photographing according to the flash to be used.

  This will be described in more detail with reference to FIGS. 5 and 6 are flowcharts showing the present embodiment. FIG. 5 shows the operation in the normal photographing mode. First, the camera body is turned on (S1). When the shutter button is pressed halfway (S2), AF control (S3), distance measurement (S4), and photometry (S5) are started. Let X be the luminance of a subject that requires flash emission. In S6, the subject brightness and the set brightness X are compared. If the result of photometry is greater than the luminance X, normal shooting is performed without flash emission (S7). When the brightness is lower than the set brightness X, the flash is started to emit light by flash.

  The distance from the subject that can be illuminated by the LED is L1. In S8, the subject distance is compared with the set distance L1. When the distance to the subject is L1 or more, the LED light emission is prohibited. Calculation of the number of xenon tubes to emit light is performed (S22), and the aperture value and exposure are determined (S24). Also, after the white balance is set to the xenon tube (S25), the shutter button is fully pressed (S26), and photographing (S28) is performed.

  Let L2 be the distance at which the distance from the subject is not adjustable by xenon tube light emission. In S9, the subject distance is compared with the set distance L2. When the distance to the subject is greater than L2, the LED and the xenon tube emit light simultaneously. At this time, the number of LEDs and xenon tubes that emit light is set (S16). When setting the number of each light emission for obtaining a predetermined amount of light, the two are compared and the LED with low power consumption is preferentially used. After the number of light emission, aperture value and exposure are determined (S16 to S18), the white balance is set to the mixed light of the LED and the xenon tube (S19), and the photographing (S28) is performed by pressing the shutter button fully (S20). Done.

  When the distance to the subject is L2 or more, only light emission by the LED is performed. At this time, the charging of the flash is stopped. After the number of light emission / aperture value and exposure are determined (S10 to S12), the white balance is set to the LED (S13), and the shutter button is fully pressed (S14) to perform photographing (S28).

  FIG. 6 shows the operation in the macro shooting mode. Steps S29 to S33 are the same as in the normal shooting mode. Let X be the luminance of a subject that requires flash emission. In S34, the subject brightness and the set brightness X are compared. If the result of photometry is greater than the luminance X, macro photography is performed without flash emission (S35). When the brightness is lower than the set brightness X, the LED is forced to emit light because light is emitted by flash. Let L2 be the distance at which the subject distance cannot be adjusted with xenon tube light emission.

  In S36, the subject distance is compared with the set distance L2. When the subject distance is larger than L2, the LED and the xenon tube emit light simultaneously. After the number of light emission, aperture value and exposure are determined (S43 to S45), the white balance is set to the mixed light of the LED and the xenon tube (S46), and when the shutter button is fully pressed (S47), shooting (S49) is performed. Done.

  When the distance to the subject is less than or equal to L2, only the light emitted by the LED is emitted. At this time, the charging of the flash is stopped. After the number of light emission / aperture value and exposure are determined (S37 to S39), the white balance is set to the LED (S40), and the shutter button is fully pressed (S41) to perform photographing (S49).

  The drive part is provided so that the irradiation range of the LED of the flash in Example 2 can be changed.

  FIG. 7 is a block diagram showing the second embodiment. Since the other flash structures and systems are the same as those of the first embodiment, the differences will be described in detail here. 7, 8, 9, 10 are xenon tubes, 3, 4, 5, 6 are LEDs, 31 is a motor for changing the irradiation angle of the LED, 11 is a Fresnel lens a, 12 is a Fresnel lens b, and 20 is a reflector. , 21 is a strobe circuit including a trigger circuit for sending a trigger signal to the xenon tube and a capacitor for causing the xenon tube to emit light.

  The number of LEDs 3, 4, 5, 6 and xenon tubes 7, 8, 9, 10 can be changed by the control circuit. The motor for driving the LED is installed so that the optical axis of the LED can be driven in the horizontal direction and the vertical direction. In accordance with the distance information obtained by AF, the CPU drives the LED so that the optical axis of the LED faces the subject.

  FIG. 8 is a flowchart showing the operation of the second embodiment. In normal shooting, even if the LED angle is changed, a large difference in illumination effect cannot be obtained. Therefore, the LED irradiation angle change determination is performed in the macro shooting mode. Let L2 be the distance at which the subject distance cannot be adjusted with xenon tube light emission.

  In S57, the subject distance is compared with the set distance L2. When the subject distance is larger than L2, the LED and the xenon tube emit light simultaneously. At this time, the irradiation angle of the LED is not changed. After the number of flashes, aperture value, and exposure are determined (S65 to S67), the white balance is set to the mixed light of the LED and the xenon tube (S68), and the shutter button is fully pressed (S69) to shoot (S71). Done.

  When the distance to the subject is less than or equal to L2, only the light emitted by the LED is emitted. At this time, the charging of the flash is stopped. The angle of the LED is changed in the focus direction of the optical system by driving the motor (S58). After the number of light emission / aperture value and exposure are determined (S59 to S61), the white balance is set to the LED (S62), and the shutter button is fully pressed (S63) to take a picture (S71).

  In Example 3, the LEDs used as the flash are arranged concentrically around the imaging lens. Since other structures and systems are the same as those of the first embodiment, the differences will be described in detail here.

  FIG. 9 is a front perspective view of the camera showing the arrangement of LEDs according to the third embodiment. 7, 8, 9, and 10 are xenon tubes, and 32, 33, 34, and 35 are LEDs. The LEDs 32, 33, 34, and 35 are arranged concentrically around the imaging lens at equal intervals, and the number of light emitted by the control circuit can be changed.

  According to the third embodiment, by arranging the LEDs concentrically, it is possible to suppress a shadow generated on the subject by flash emission during macro photography. The LEDs that emit light are selected to be symmetrical. First, when there is one LED to emit light, the LED 32 is caused to emit light, and when two LEDs are used, the LEDs 32 and 35 or the LEDs 33 and 34 located at symmetrical positions with respect to the photographing lens 2 are selected. The same applies when the number of light emission increases thereafter.

1 is a front perspective view of a camera according to a first embodiment of the present invention. 1 is a rear perspective view of a camera according to a first embodiment of the present invention. 1 is a configuration diagram of a flash unit of a camera according to a first embodiment of the present invention. 1 is a block diagram of a camera according to a first embodiment of the present invention. The flowchart which showed the operation | movement at the time of normal imaging | photography of the camera which concerns on the 1st Embodiment of this invention. The flowchart which showed the operation | movement at the time of macro imaging | photography of the camera which concerns on the 1st Embodiment of this invention. The block diagram of the flash part of the camera which concerns on the 2nd Embodiment of this invention The flowchart which showed the operation | movement at the time of macro imaging | photography of the camera which concerns on the 2nd Embodiment of this invention. Front perspective view of a camera according to a third embodiment of the present invention

Explanation of symbols

1 Camera body 2 Photo lens 3, 4, 5, 6 LED
7, 8, 9, 10 Xenon tube 11 Fresnel lens a
12 Fresnel lens b
18 Flash switch button 19 Normal shooting / macro shooting switch button 20 Reflector 21 Strobe circuit 22 LED / Xenon tube light emission control circuit

Claims (13)

  A camera having a plurality of different types of light sources, the light sources being arbitrarily switched according to the distance to the subject, and the amount of light of the flash being controlled so that appropriate exposure can be obtained.   The camera according to claim 1, wherein the amount of light is adjusted according to the type and number of light sources that emit light.   The camera according to claim 1, wherein the light source that emits light is a xenon tube or an LED.   The camera according to claim 1, wherein white balance can be controlled in accordance with a change in the type of the light source.   The camera according to claim 1, wherein Fresnel lenses having different condensing characteristics are provided in front of the different types of light sources.   2. The camera according to claim 1, wherein when the plurality of types of different light sources emit light at the same time, the number of light emission is compared with each other so that the light source with low power consumption emits light preferentially. A camera characterized by controlling.   4. The camera according to claim 3, wherein the LED that emits light is preferentially selected from those at a short distance from the photographing lens.   The camera according to claim 3, wherein the LED can be used as auxiliary light used when performing AF control.   The camera according to claim 3, wherein at least one of the LEDs can change an irradiation angle depending on a distance of a subject.   The camera according to claim 3, wherein the plurality of LEDs are arranged concentrically around an imaging lens.   A camera having a plurality of types of different light sources and a flash capable of controlling white balance in accordance with the color temperature of the light source that emits light.   The camera according to claim 11, wherein the amount of light of the flash is adjusted by the type and number of light sources that emit light.   The camera according to claim 11, wherein the light source that emits light is a xenon tube or an LED.

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