KR20090119452A - Apparatus for measuring the amount of light in apparatus for photographing, and method of measuring the amount of light and photographing images using the apparatus for measuring - Google Patents

Abstract

PURPOSE: An apparatus for measuring the amount of light in an apparatus for photographing, and a method of measuring the amount of light and photographing images using the apparatus for measuring are provided to implement a live view function by opening a shutter without using a reflective mirror. CONSTITUTION: A device for measuring brightness of the digital photographing device comprises a lens unit, a shutter, and a metering sensor. The lens unit(100) has multiple lenses. The lens unit transmits the light representing the image of the subject. The shutter(126) selectively secludes the light entering to the image sensor(122) through the lens unit. The metering sensor(110) is arranged to incident the light showing the image of a subject which is reflected to the reflecting surface of shutter.

Description

Metering device of digital photographing apparatus, metering method and photographing method using same {Apparatus for Measuring the Amount of Light in Apparatus for Photographing, and Method of Measuring the Amount of Light and Photographing Images Using the Apparatus for Measuring}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital photographing apparatus, and more particularly, to a metering apparatus for providing light quantity information that is a basis for determining an exposure amount of a digital photographing apparatus, a metering method, and a photographing method using the same.

Digital imaging devices are image pickup devices that use image sensors such as CCD and CMOS instead of film. Digital photographing devices are widely used due to the advantages of being resistant to noise, reproducing high quality signals at low cost, miniaturizing image storage media, and reducing their volume.

Digital photographing apparatuses can be broadly classified into a range finder method and a lens reflection method.

The range finder system has a view finder for viewing a subject separately from the lens, and focuses using a pair of range finders. This method is employed in most automatic compact cameras and entry-level digital cameras on the market. The principle of the range finder is to measure the distance by matching the time difference. The viewfinder is usually located in the upper left of the lens and because of its different position, there is a difference between the scene seen through the viewfinder and the scene actually shot through the lens. This is called parallax, and since the parallax becomes deeper as the distance between the subject and the camera gets closer, there is a disadvantage that the parallax correction should be performed when taking close-up pictures. The range finder has a simple structure without a mirror and a lens shutter method, so that the camera's vibration can be suppressed because there is less vibration and noise of the camera when shooting and there is no impact caused by the reflection mirrors seen in a single-lens reflex camera. However, because the lens shutter is adopted, lens replacement is not possible and the range of utilization of the aperture and shutter speed is inferior to that of the single lens reflex camera.

The lens reflex camera is configured to use the reflection mirror to view the images entered into the lens with a viewfinder. According to the number of reflection mirrors, the single lens reflex (SLR) camera and the binocular lens reflection camera are used. Are distinguished. Most high-end cameras have an SLR structure. The schematic structure of the SLR camera is shown in FIG. The light representing the image of the subject introduced through the lens unit 110 is reflected by the reflection mirror 12 and transmitted to the finder screen 13, and sequentially passes through the penta-prism 15 in an upright position. After the change, it appears in the viewfinder 16. At this time, some of the light is configured to enter the photometric sensor 14. When the shutter 17 is opened for photographing, the reflection mirror 12 positioned in front of the image sensor 18 is raised, and light representing the image of the subject entering through the lens unit 10 is formed at the image sensor 18, thereby photographing. Is performed.

In the case of an SLR camera in which image capturing is performed in this manner, since the reflection mirror 12 always covers the image sensor 18 at a point other than at the moment of shooting, the live view (which is not shown) checks the image with a display device such as an LCD (not shown). live view) function is not supported. Therefore, in order to shoot, it is inconvenient to look at the image of the subject to be photographed only through the optical viewfinder 16.

Recently, however, this problem has been recognized, and an SLR camera having a reflective mirror and allowing live view has emerged. A metering and photographing method in an SLR camera capable of live view is shown in FIG. 2. In the case of an SLR camera capable of live view, in the recording standby state, the reflection mirror 12 is moved up to provide a live view, and when the shutter release button is operated halfway, the reflection mirror 12 is moved for metering. In the down state, when the shutter release button is fully pressed, the reflection mirror 12 is moved up again, and then the shutter is opened at a predetermined speed. When the photographing is completed, the reflection mirror 12 is moved to the down state. As such, the reflection mirror 12 must be moved to the up state, the down state, the up state, and the down state until the live view is taken after the live view is taken. This is because the reflection mirror 12 should be placed in the down state for metering and AF (auto focusing) just before photographing. Therefore, SLR cameras with live view function take longer to shoot than SLR cameras without live view function. In addition, there is a problem that frequently misses the best time to shoot because it takes a long time between shooting.

On the other hand, as a metering method employed by digital compact cameras, there is a method of converting light representing an image of a subject into electrical information in an image sensor to create an image, and performing metering using the image. This method performs the metering without using the metering sensor, but the photographing time is similarly long because it requires imaging the light representing the image of the subject in the image sensor and processing the image information to perform the metering operation.

The metering apparatus of the digital photographing apparatus, the metering method and the photographing method using the same, to solve the above problems, while realizing a live view function by always opening the shutter without using a reflection mirror, and at the same time an image sensor In order to shorten the time required for photographing by performing a photometric measurement using a photometric sensor instead of

In order to solve the above problems, according to an aspect of the present invention, (i) a lens unit having a plurality of lenses, the light transmitting the image representing the subject of the subject, (ii) light passing through the lens unit to enter the image sensor And a shutter having a reflective surface for reflecting light on at least a portion of the surface where light enters, and (iii) a photometric sensor to which light representing an image of a subject reflected on the reflective surface of the shutter is incident. Disclosed is a light metering device of a digital photographing apparatus including a.

In this way, by reflecting the light representing the image of the subject to the reflective surface of the shutter to enter the photometric sensor to perform the metering, it is not necessary to use a separate reflection mirror and penta prism. Therefore, the volume of the digital imaging apparatus can be significantly reduced.

The apparatus may further include an aperture that adjusts an incident amount of light representing an image of a subject incident from the outside and transmitted through the lens unit, and adjusts a depth of the subject. When the metering is maximized, the depth of the subject can be deepened to increase the resolution of the image entering the metering sensor. Therefore, the resolution of the image used for metering is improved, thereby making the metering more accurate.

The lens unit may further include a focusing lens for adjusting the focus, and may adjust the focus so that the focus of the light representing the image of the subject immediately before the metering is on the reflective surface of the shutter instead of the image sensor surface. This improves the image quality of the image that is reflected on the reflective surface of the shutter when metering and enters the metering sensor, and the metering becomes more accurate.

The shutter is a focal plane shutter, and the focal plane shutter includes a first film and a second film, and the light is formed on a surface of any one of the first film and the second film on which the light representing the image of the subject comes into. A reflective surface may be formed to reflect the light. The reflective surface may comprise a gray material having a reflectance of 18% to 50%. The shutter may be driven such that any one of the first film and the second film on which the reflective surface is formed reflects light representing an image of a subject during photometry. As described above, photometry may be performed by further forming only a reflective surface on at least a portion of one surface of the conventional shutter.

According to another aspect of the present invention, (i) determining whether the shutter release switch is in the half-shutter operation state, and (ii) if the shutter release switch is in the half-shutter operation state, reflected on one side of the shutter through the photometric sensor. Disclosed is a method of metering and photographing in a digital photographing apparatus comprising receiving light representing an image of a subject and measuring brightness of the light.

In this way, by reflecting the light representing the image of the subject to the reflective surface of the shutter to enter the photometric sensor to perform the metering, it is not necessary to use a separate reflection mirror and penta prism. Therefore, the volume of the digital imaging apparatus can be significantly reduced.

As an embodiment for improving the image quality of an image incident to a photometric sensor, in the photometric and photographing method, before the step of measuring the brightness of the light, the focus of the light representing the image of the subject is focused on one surface of the shutter. Adjusting the focus so as to bear. In the metering and photographing method, after measuring the brightness of the light, determining an appropriate exposure value using the measured brightness information of the light and focusing the image sensor to focus the light on the image sensor. It may further comprise the step of adjusting.

By adjusting the focus so that the focus of the light representing the subject's image is on the reflective surface of the shutter rather than the image sensor surface, the image quality is reflected on the reflective surface of the shutter during metering to improve the image quality of the image entering the photometric sensor. More accurate. In addition, no time is required to adjust the focus so that the focus is on the image sensor. Therefore, it is possible to prevent the shooting time from lengthening.

As another embodiment for improving the image quality of an image incident to the photometric sensor, the photometric and photographing method further includes the step of setting the maximum aperture value so as to tighten the aperture most before the step of measuring the brightness of the light. It may include. In addition, the metering and photographing method, after the step of measuring the brightness of the light, determining the appropriate exposure value by using the measured brightness information of the light; And adjusting the aperture value based on the determined exposure value.

When the metering is maximized, the depth of the subject can be deepened to increase the resolution of the image entering the metering sensor. Therefore, the resolution of the image used for metering is improved, thereby making the metering more accurate.

The metering apparatus of the digital photographing apparatus, the metering method and the photographing method using the same according to an embodiment of the present invention can implement the live view function continuously in the shooting standby state by always opening the shutter without using the reflection mirror.

In addition, the metering apparatus, the metering method, and the photographing method of the digital photographing apparatus according to the embodiment of the present invention can perform photographing quickly because the metering is performed using the metering sensor instead of the image sensor.

Hereinafter, with reference to the embodiments shown in the accompanying drawings, the present invention will be described in detail.

3 is a diagram schematically illustrating a light metering device of a digital photographing apparatus according to an embodiment of the present invention. Referring to the drawing, the photometering apparatus of the digital photographing apparatus includes an aperture 101, a lens unit 100, a shutter 126, and a photometric sensor 110.

The diaphragm 101 may adjust an incident amount of light entering the digital image photographing apparatus and representing an image of a subject transmitted through the lens unit 100. In addition, the aperture 101 serves to change the depth of the subject. Assuming that the other conditions are the same, the larger the numerical value of the diaphragm 101 is, the smaller the amount of light transmitted through the lens unit 100 decreases as the diaphragm 101 decreases, but the depth of the subject deepens to focus on a specific distance. When it is clear, the range before and after the clear picture is lengthened. On the contrary, the smaller the numerical value of the diaphragm 101, the greater the amount of light transmitted through the lens unit 100 as the aperture 101 is opened. The range is shortened.

The lens unit 100 includes a plurality of lenses, and transmits the light representing the image of the subject to reach the image sensor 122. The lens unit 100 of the digital photographing apparatus having an auto focusing function may further include a focusing lens. Auto focusing may use a contrast detection method. When light representing an image of a subject entered through the lens unit 100 is incident to the image sensor 122, the image sensor 122 measures contrast of a portion of the subject (eg, a center portion). If the contrast value is low, auto focusing is performed by moving the focusing lens back and forth on the optical axis and measuring the instant when the contrast value of the subject formed on the image sensor 122 becomes maximum. By moving the focusing lens to a position corresponding to the moment when the contrast value is maximum, the focus may be adjusted so that light representing the image of the subject is accurately imaged on the surface of the image sensor 122.

The shutter 126 selectively blocks light that passes through the lens unit 100 and enters the image sensor 122. At least a part of the surface of the shutter 126 on which light enters is formed with a reflective surface that reflects light. The shutter 126 may be, for example, a focal plane shutter 126. The focal plane shutter 126 is provided just before the focal plane of the lens, and is a shutter 126 in which two sheets of fabric or metal film move left and right or up and down. The focal plane shutter 126 may be formed of a first film (not shown) and a second film (not shown), and may be a front curtain and a thick film, respectively. The focal plane shutter 126 adjusts the amount of light entering the image sensor 122 by adjusting only the width of the slit, which is an interval between the front curtain and the rear curtain, with the moving speed of the front curtain and the rear curtain constant. Can be. On the contrary, the focal plane shutter 126 may adjust the amount of light entering the image sensor 122 by adjusting the moving speed of the front curtain and the rear curtain while maintaining the slit width between the front curtain and the rear curtain. Alternatively, the focal plane shutter 126 may adjust the amount of light entering the image sensor 122 by simultaneously adjusting the moving speed of the front curtain and the rear curtain and the width of the slit, which is an interval between the front curtain and the rear curtain.

A reflective surface is formed on at least a part of the surface of the shutter 126 on which the light representing the image of the subject comes in. As an example of the reflective surface, the reflective surface may be formed on one surface of the front curtain of the focal plane shutter 126. The reflecting surface may be formed of any material that can reflect light at a predetermined reflectance. For example, the surface of the curtain on which the light enters may be formed of 40% gray, 36% gray, 18% gray, or the like. The 18% gray material is an intermediate between white and black with 18% reflectivity and whiter with higher reflectance. In exposure compensation, when the reflectivity of the reflecting surface is increased, the amount of light reflected on the reflecting surface becomes larger among the light representing the image of the subject reflected on the subject, and when the reflecting surface is low, the reflecting surface of the subject is reflected on the subject. Since the amount of light reflected by the reflective surface becomes smaller among the light representing the image, the exposure compensation value should be changed according to the reflectance of the reflective surface. In the case of the gray material, it is preferable to use 18% or more of gray in consideration of reflectance, and when the reflectance is too high, it is preferable to use 50% or less of gray in consideration of the aesthetic appearance of the digital imaging apparatus. As a material formed on the reflective surface, although a gray material having a predetermined reflectance is taken as an example, the protection scope of the present invention does not necessarily correspond to this.

The photometric sensor 110 may be a position at which light representing the image of the subject may be reflected and incident on the reflective surface of the shutter 126 without interfering with a path of light representing the image of the subject entering the image sensor 122. Should be placed in. The photometric sensor 110 may be disposed in a horizontal plane, as shown in FIG. 3. However, the protection scope of the present invention is not necessarily limited thereto.

Metering is the measurement of the brightness of the subject by the digital imaging apparatus, and the metering value is used to determine the amount of light that the digital imaging apparatus should expose to the image sensor 122. Types of metering methods include an average metering method for measuring the average brightness of a subject with one sensor, a center weighted metering method for metering the center and periphery separately, and a few areas (e.g., 5 Division, 16 divisions, 32 divisions, 256 divisions, and the like, and a multi-division metering method for calculating and a spot metering method for metering a specific narrow area.

FIG. 4 is a flowchart illustrating a method of performing metering and photographing by the metering apparatus shown in FIG. 3. Referring to FIG. 4, a metering and photographing method in a digital photographing apparatus according to an exemplary embodiment will be described.

When the user turns on the digital imaging apparatus and selects a shooting mode, the shutter 126 is opened so that the light indicating the image of the subject enters the image sensor 122, so that the live view is displayed through a display window such as an LCD in the standby state. That is, since the digital imaging apparatus of the present invention does not use the reflection mirror and the penta prism, the live view may be continuously performed as long as the shutter 126 is opened.

When the user presses the shutter release button halfway to operate the image for photographing the image (S110), the lens unit 100 performs the auto focus adjustment function using the above-described contrast detection method (S120). However, in the light metering method according to the exemplary embodiment of the present invention, the focus is adjusted to the reflective surface of the shutter 126 instead of the image sensor 122. To this end, a contrast value for an image of a subject formed on the image sensor 122 is used, and focusing is performed on the reflective surface of the shutter 126 in consideration of the distance d between the shutter 126 and the image sensor 122. Adjust the movement of the lens unit 100 to come. In designing the digital imaging apparatus, the distance d between the shutter 126 and the image sensor 122 is a predetermined value, and since the change in the focal length according to the movement of the focusing lens is also known, the image sensor 122 Contrast values for the image of the appearing subject may be used to focus on the reflective surface of the shutter 126.

After focusing is performed so that the focus is on the reflective surface of the shutter 126, the shutter 126 is closed to the extent that light representing the image of the subject can be reflected on the reflective surface of the shutter 126 (S130). In the focal plane shutter 126, the shutter 126 may be closed by moving the reflective surface of either the first or the second film to a height corresponding to the image sensor 122. At least some of the light representing the image of the subject reflected on the reflective surface of the shutter 126 enters the photometric sensor 110. The photometric sensor 110 measures the brightness of the light representing the image of the subject (S140). The digital image photographing apparatus determines an optimal exposure value based on the information on the brightness of the light. As described above, metering may be performed by injecting light representing the image of the subject into the photometric sensor 110 using the reflective surface of the shutter 126 without using the reflective mirror and the penta prism.

After the light representing the image of the subject is reflected on the reflective surface of the shutter 126 and enters the photometry sensor 110, an auto focusing function is performed such that the focus is on the image sensor 122. The focus adjustment function (auto focus adjustment when the focus is on the image sensor surface 122) does not need to repeat the same process as in the auto focus adjustment when the focus is on the shutter 126 surface. This is because the position of the focusing lens for focusing to adjust the focus to the image sensor 122 at the time of the automatic focusing when the focus is on the shutter 126 surface is known.

When the shutter release button is fully pressed (S160), the shutter 126 is opened at a predetermined shutter speed so that exposure is performed and light representing the image of the subject enters the image sensor 122 (S170). Light incident on each cell of the image sensor 122 is converted into an electrical signal and transmitted to an operation unit, whereby an image is formed, thereby completing photographing.

Since the metering and photographing method according to an embodiment does not use the reflection mirror, it is not necessary to repeat the process of raising and lowering the reflection mirror, and only needs to close and open it once with the reflective surface of the shutter 126 for metering. Compared to the time for moving the reflection mirror up or down, the opening and closing time of the shutter 126 is much shorter. Therefore, the time required for metering and photographing can be shortened as compared with the related art, and the time between photographing can be shortened so that missed scenes can hardly occur. In addition, since the SLR camera does not use the reflection mirror and the penta prism, the volume of the digital imaging apparatus can be significantly reduced.

FIG. 5 is a flowchart illustrating another embodiment of a method of performing metering by the metering apparatus shown in FIG. 3. Referring to FIG. 5, a light metering and a photographing method in a digital photographing apparatus according to another exemplary embodiment will be described.

When the user turns on the digital imaging apparatus and selects a shooting mode (S200), the shutter 126 is opened and light indicating the image of the subject enters the image sensor 122, so that a display window such as an LCD is displayed in the standby state. Live view is performed. That is, since the digital image photographing apparatus of the present invention does not use the reflection mirror and the penta prism, the live view may be continuously performed as long as the shutter 126 is opened.

When the user presses the shutter release button halfway for the image capturing operation (S210), the aperture 101 is tightened to the maximum, thereby deepening the depth of the subject (S220).

Then, the shutter 126 is closed to the extent that light representing the image of the subject passing through the lens unit 100 can be reflected on the reflective surface of the shutter 126 (S230). In the focal plane shutter 126, the shutter 126 may be closed by moving the reflective surface of either the first or the second film to a height corresponding to the image sensor 122. Light representing the image of the subject reflected on the reflective surface of the shutter 126 enters the photometric sensor 110. The photometric sensor 110 measures the brightness of the light representing the image of the subject (S240). Since the depth of the subject has deepened, the resolution of the image produced by the photometric sensor 110 becomes a photometric level. 6A to 6G are views illustrating comparison of an image incident on the photometric sensor 110 as the aperture 101 value is gradually decreased. As shown in FIG. 6A, when the diaphragm 101 was tightened to the maximum value of the crab, it was found that the resolution of the image made in the photometric sensor 110 was the best and thus used for photometric measurement.

The calculating unit of the digital image photographing apparatus determines an appropriate exposure amount based on the information on the brightness of the light. As such, there is an advantage in that photometry can be performed by injecting light representing an image of a subject into the photometric sensor 110 using the reflective surface of the shutter 126 without using a reflective mirror and a penta prism.

After the light representing the image of the subject is reflected on the reflective surface of the shutter 126 and enters the photometry sensor 110, the aperture 101 is returned to a position according to the original aperture 101 value (S250). 126 is opened again (S260).

Then, an auto focusing function is performed so that the focus is on the image sensor 122 surface (S270). The auto focusing function uses the contrast value for the image of the subject on the image sensor 122, but focuses the shutter 126 surface in consideration of the distance d between the shutter 126 and the image sensor 122. It is performed by adjusting the movement of the lens unit 100 to come to.

When the shutter release button is fully pressed (S280), the exposure is performed while the shutter 126 is opened at a predetermined shutter speed, and light representing the image of the subject enters the image sensor 122 (S290). Light incident on each cell of the image sensor 122 is converted into an electrical signal and transmitted to an operation unit, whereby an image is formed, thereby completing photographing.

In the above-described metering and photographing method according to another embodiment, since the reflection mirror is not used, there is no need to repeat the process of raising and lowering the reflection mirror, and only the process of setting the aperture 101 to the minimum aperture for metering is necessary. Therefore, the time required for metering and photographing can be shortened as compared with the related art. In addition, since the SLR camera does not use the reflection mirror and the penta prism, the volume of the digital imaging apparatus can be significantly reduced.

The present invention can be used in the industry of manufacturing digital imaging apparatus.

1 is a view schematically showing the internal side structure of a conventional SLR camera.

FIG. 2 is a flowchart illustrating a method of performing metering and photographing by the metering apparatus shown in FIG. 1.

3 is a diagram schematically illustrating a light metering device of a digital photographing apparatus according to an embodiment of the present invention.

4 is a flowchart illustrating an embodiment of a method of performing metering by the metering apparatus shown in FIG. 2.

FIG. 5 is a flowchart illustrating another embodiment of a method of performing metering by the metering apparatus shown in FIG. 2.

6A to 6G are views for comparing images incident on the photometric sensor as the aperture value is gradually decreased.

Brief description of symbols for the main parts of the drawings

100: lens unit 101: aperture

110: photometric sensor 122: image sensor

126: shutter

Claims (11)

A lens unit having a plurality of lenses and through which light representing an image of a subject is transmitted; A shutter selectively blocking light entering the image sensor through the lens unit and having a reflective surface reflecting light on at least part of a surface of the light input side; And And a photometric sensor arranged to enter light representing an image of a subject reflected from the reflective surface of the shutter. According to claim 1, The photometering apparatus of the digital photographing apparatus of claim 1, further comprising an aperture that adjusts an incident amount of light representing an image of a subject incident from the outside and passes through the lens unit, and adjusts a depth of the subject. The method of claim 2, The lens unit of claim 1, wherein the lens unit further comprises a focusing lens for adjusting the focus. According to claim 1, The shutter is a focal plane shutter, and the focal plane shutter includes a first film and a second film, and the light is formed on a surface of any one of the first film and the second film on which the light representing the image of the subject comes into. A light metering device of a digital photographing apparatus, wherein a reflecting surface for reflecting light is formed. According to claim 1, And the reflecting surface comprises a gray material having a reflectance of 18% to 50%. According to claim 1, And the shutter is driven such that any one of the first film and the second film on which the reflective surface is formed reflects the light representing the image of the subject when the light is metered. Determining whether the shutter release switch is in the half shutter operation state; And When the shutter release switch is in the half-shutter operation state, receiving the light representing the image of the subject reflected on one surface of the shutter through a photometric sensor and measuring the brightness of the light; metering and photographing method in a digital photographing apparatus comprising a . The method of claim 7, wherein Before measuring the brightness of the light, And adjusting focus so that a focus of light representing an image of a subject is formed on one surface of the shutter. After measuring the brightness of the light, And determining an appropriate exposure value by using the measured brightness information of the light. The method of claim 8, After determining the appropriate exposure value, Adjusting focus so that a focus of light representing an image of the subject is brought into the image sensor; And And converting light entering the image sensor into an electrical signal to obtain image information. The method of claim 7, wherein Before measuring the brightness of the light, Setting the aperture value to the maximum so as to tighten the aperture the most; After measuring the brightness of the light, Determining an appropriate exposure value by using the measured brightness information of the light; And And adjusting the aperture value based on the determined exposure value. The method of claim 7, wherein Before measuring the brightness of the light, Closing the shutter so that the light representing the image of the subject is reflected and incident on the photometric sensor; After measuring the brightness of the light, And opening the shutter at a predetermined speed such that light representing an image of a subject can be incident on the image sensor.

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