JP2005114835A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control the emitted light quantity of a strobe in accordance with the light quantity detected by a photodetecting sensor, even in the case the photodetecting sensor is installed in a finder lens having an optical system independent of a photographic lens. <P>SOLUTION: The digital camera (100) is provided with a light emitting means (2) for emitting light toward an object, a light receiving means (3) for receiving the light reflected by the object after being emitted from the light emitting means, and a light control means (4) for controlling the light emitting means so as to stop the light emission on the basis of information that the light quantity received by the light receiving means reaches a prescribed light control quantity, and the digital camera (100) is provided with the photographic lens (51) and the finder lens (52) having the optical system independent of the photographic lens, and the light receiving means is arranged in the finder lens, and the digital camera is also provided with a light control quantity deciding means (1) for deciding the light control quantity on the basis of the diaphragm value of the photographic lens and the diaphragm value of the finder lens. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital camera.

2. Description of the Related Art Conventionally, as in the case of a single-lens reflex camera, a camera that incorporates a light receiving sensor in a photographic lens and performs flash light control is known. Recently, digital cameras have become mainstream, and attempts have been made to apply similar techniques to digital cameras.
However, in a digital camera, it is difficult to provide a light receiving sensor on a photographic lens due to space limitations. Therefore, a technique for providing a light receiving sensor on a finder lens has been developed (see, for example, Patent Document 1).
Japanese Patent No. 2544427

  However, if a finder lens that has an optical system independent of the photographic lens is equipped with a light receiving sensor and the flash output is controlled by the amount of light detected by the light receiving sensor, the difference in aperture value change during zooming of the photographic lens and finder lens Therefore, it has been difficult to properly control the amount of light emitted from the strobe.

  Therefore, even if the light receiving sensor is provided in a finder lens having an optical system independent of the photographing lens, an object of the present invention is to appropriately control the light emission amount of the strobe according to the light amount detected by the light receiving sensor. It is to provide a digital camera that can.

  In order to solve the above problems, the invention described in claim 1 includes: a light emitting unit that emits light toward a subject; a light receiving unit that receives light emitted from the light emitting unit and reflected by the subject; and the light receiving unit. A dimming unit that performs control to stop light emission by the light emitting unit based on the fact that the received light amount reaches a predetermined dimming amount, and has a photographing lens and an optical system independent of the photographing lens A digital camera having a finder lens and having the light receiving means provided in the finder lens, wherein the light control amount is determined based on an aperture value of the photographing lens and an aperture value of the finder lens A light control amount determining unit is provided.

  According to a second aspect of the present invention, in the digital camera according to the first aspect of the present invention, the digital camera includes a storage unit that stores a dimming amount corresponding to a combination of the aperture value of the photographing lens and the aperture value of the finder lens. The light quantity determining means adjusts the dimming corresponding to the combination of the aperture value of the photographic lens and the aperture value of the finder lens from the storage means based on the set aperture value of the photographic lens and the aperture value of the finder lens. The quantity is extracted and determined.

  According to a third aspect of the present invention, in the digital camera according to the first aspect, the dimming amount determination unit is configured to perform the photographing based on the set aperture value of the photographing lens and the aperture value of the finder lens. The present invention is characterized in that a light control amount corresponding to a combination of a lens aperture value and a viewfinder lens aperture value is calculated and determined.

  According to the first aspect of the present invention, the light control amount determining means determines the light control amount for controlling the light emission amount of the light emitting means based on the aperture value of the photographing lens and the aperture value of the finder lens. Therefore, it is possible to eliminate a difference in aperture value change during zooming of the taking lens and the viewfinder lens. Therefore, even when the light receiving means is provided in a finder lens having an optical system independent of the photographing lens, the light emission amount of the light emitting means can be controlled appropriately.

  According to the second aspect of the invention, since the dimming amount corresponding to the combination of the aperture value of the photographing lens and the aperture value of the finder lens is stored in the storage unit, the dimming amount determination unit is the storage unit. Since the dimming amount can be determined simply by accessing and setting the aperture value at each focal length, the light emission amount of the light emitting means can be appropriately controlled by a simple method.

  According to the third aspect of the present invention, the dimming amount determining means determines the aperture value of the photographic lens and the aperture value of the finder lens based on the set aperture value of the photographic lens and the aperture value of the finder lens. The light control amount corresponding to the combination is calculated and determined. Therefore, since the light control amount can be determined simply by setting the aperture value of each lens in advance, it is possible to appropriately control the light emission amount of the light emitting means by a simple method.

Hereinafter, the best mode of a digital camera according to the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, a digital camera 100 includes a control unit 1 that controls operation of each unit, a flash unit 2 that emits light toward a subject based on a control signal received from the control unit 1, and the flash unit. A light-receiving unit 3 as a light-receiving unit that receives light emitted from the unit 2 and reflected by the subject, and performs control for stopping light emission by the flash unit 2 based on the fact that the received light amount reaches a predetermined light control amount. As a storage means for storing a light emission stop signal generation unit 4 as a light unit, a photographing unit 5 for photographing a subject, a display unit 6 for displaying a photographed image, and an aperture value of a finder lens 52 corresponding to an aperture value of a photographing lens 51 The memory | storage part 7 grade | etc., Is provided.
Further, the digital camera 100 is provided with a finder lens 52 having an optical system independent of the photographing lens 51 of the photographing unit 5. The taking lens 51 and the finder lens 52 are each composed of a zoom optical system, and are interlocked by an interlocking mechanism (not shown). For example, when an instruction to switch from the wide-angle shooting mode to the telephoto shooting mode is performed by operating a zoom button provided in the digital camera 100, the taking lens 51 performs zooming from the wide-angle shooting position to the telephoto shooting position, and is not illustrated. The viewfinder lens 52 is also zoomed from the wide-angle side to the telephoto side by an interlocking mechanism or the like. In addition, the open aperture value changes according to zooming, but the amount of change between the photographing lens 51 and the viewfinder lens 52 does not match. When the telephoto shooting mode is switched during the wide-angle shooting mode, the open aperture value of the taking lens 51 is changed from F2 to F4, and the open aperture value of the viewfinder lens 52 is changed from F2.8 to F8. The finder lens 52 is used when the user takes a picture of a subject and sets the composition of the photograph. The finder lens 52 includes the light receiving unit 3 therein.

The control unit 1 includes a CPU 11 that performs various arithmetic processes, a RAM 12 that is used as a work area for the CPU 11, a ROM 13 that stores a system program and the like necessary for the CPU 11 to control each unit, and the like. .
The CPU 11 reads out a program stored in the ROM 13 and develops it in the RAM 12, and controls instructions to each unit and data transmission / reception based on the program.

Specifically, the CPU 11 corresponds to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 from the storage unit 7 based on the set aperture value of the photographic lens 51 and the aperture value of the finder lens 52. Functions as a dimming amount determining means for extracting and determining the dimming amount to be determined.
Further, the CPU 11 calculates the light control amount corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 based on the set aperture value of the photographic lens 51 and the aperture value of the finder lens 52. It also functions as a dimming amount determination means that determines the above.

The ROM 13 stores programs for the CPU 11 to execute various functions.
Specifically, the ROM 13 has a light emission control program 13a that realizes a function of performing light emission control of the flash unit 2 that emits light toward the subject.
Further, the ROM 13 adjusts the adjustment corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 from the storage unit 7 based on the set aperture value of the photographic lens 51 and the aperture value of the finder lens 52. It has the 1st light control amount determination program 13b which implement | achieves the function which extracts and determines light quantity.
Further, the ROM 13 calculates the light control amount corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 based on the set aperture value of the photographic lens 51 and the aperture value of the finder lens 52. And a second light control amount determination program 13c for realizing the function to be determined.

  The strobe unit 2 emits strobe light whose light emission timing and light emission amount are adjusted to the subject. The strobe unit 2 includes a capacitor for accumulating charges for emitting strobe light, a charging circuit for charging the capacitor, and a light emitting unit (none of which is shown) made of a xenon tube or the like. In the strobe unit 2, the voltage of the power source supplied from the control unit 1 is converted into a high voltage by the converter circuit, current is supplied to the charging circuit, and electric charge as light emission energy is accumulated in the capacitor.

  The light receiving unit 3 includes, for example, a photodiode (PD) 31 and an integration circuit 32 that integrates a photocurrent from the photodiode 31 and generates an integrated voltage as a light receiving element.

  The light emission stop signal generation unit 4 is mainly composed of a comparison circuit including a comparator and the like, and emits light from the comparator when the integrated voltage from the light receiving unit 3 reaches a reference voltage (predetermined light control amount) set by a variable voltage source. A stop signal is output.

  The imaging unit 5 includes an imaging lens 51 made of glass or plastic, and an imaging element such as a charge coupled diode (CCD) or a complementary metal oxide semiconductor (CMOS), and an image input via the imaging lens 51. Is converted into an electrical signal by the imaging element to generate image data. The generated image data is displayed on the display unit 6.

  The display unit 6 is configured by an LCD (Liquid Crystal Display) panel or the like, and performs screen display based on display data input from the control unit 1. In addition, the display unit 6 displays an image taken by the photographing unit 5 as a preview, an image taken by a user instruction, and the like.

In the storage unit 7, the light emission amount corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 and the light control amount corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 are stored. A certain voltage value is stored. Specifically, as shown in FIG. 2, the aperture value in the wide-angle shooting mode and the aperture value in the telephoto shooting mode are set for each lens. For example, the aperture value of the shooting lens 51 is F = 2. If the aperture value of the finder lens 52 is F = 2.8 and the light control amount (reference voltage) is 0.5 V, the aperture value of the photographic lens 51 is F = 4, and the aperture value of the finder lens 52 is When the value is F = 8, first, since the aperture value of the imaging lens 51 is doubled, it is necessary to increase the light emission amount by 2 ² = 4 times. However, since the aperture value of the finder lens 52 is 2.8 times, the amount of light received by the light receiving unit 3 is 1 / (2.8) ² = 1/8 times. Therefore, the amount of received light when the aperture value of the finder lens 52 is F = 8 is 4 × (1/8) = ½ times, and therefore, the aperture value of the finder lens 52 is F = 2. In order to obtain the same light control amount, the reference voltage may be set to 1V.

Next, the light emission control of the flash unit 2 will be described with reference to the flowchart of FIG.
When the user selects and inputs a shooting mode when shooting a subject, the CPU 11 determines whether or not a signal indicating that the wide-angle shooting mode has been selected has been received (step S1). Here, when the CPU 11 determines that the signal indicating that the wide-angle shooting mode is selected (step S1; YES), the CPU 11 accesses the storage unit 7 and extracts the light emission amount in the wide-angle shooting mode. Are determined (step S2). Next, the CPU 11 executes the first dimming amount determination program 13b to extract and determine the dimming amount in the wide-angle shooting mode (step S3). Next, the light emission stop signal generation unit 4 sets the determined light control amount (reference voltage) with a variable voltage source (step S4).

  Next, the CPU 11 causes the flash unit 2 to emit light by executing the light emission control program 13a (step S5). At this time, the comparator of the light emission stop signal generation unit 4 waits for the comparison circuit of the light emission stop signal generation unit 4 to reach a predetermined light control amount (reference voltage). Next, the CPU 11 determines whether or not the capacitor of the flash unit 2 has reached a predetermined light control amount based on the comparison result of the comparator (step S6). Here, when the CPU 11 determines that the capacitor of the flash unit 2 has reached a predetermined light control amount (step S6; YES), the light emission stop signal generation unit 4 sends the generated light emission stop signal to the flash unit 2. Then, the emission is stopped (step S7), and this process is terminated. On the other hand, when the CPU 11 determines that the capacitor of the flash unit 2 has not reached the predetermined dimming amount (step S6; NO), the CPU 11 returns to step S6 again, and the capacitor of the flash unit 2 has the predetermined dimming amount. The determination in step S6 is repeated until it is determined that it has been reached.

  In step S1, when the CPU 11 determines that the signal indicating that the wide-angle shooting mode is selected (step S1; NO), the CPU 11 receives the signal indicating that the telephoto shooting mode is selected. Is determined (step S8). Here, when the CPU 11 determines that a signal indicating that the telephoto shooting mode is selected (step S8; YES), the CPU 11 accesses the storage unit 7 and extracts the light emission amount in the telephoto shooting mode. Are determined (step S9). Next, the CPU 11 executes the first dimming amount determination program 13b to extract and determine the dimming amount in the telephoto shooting mode (step S10).

Next, the CPU 11 returns the process to step S4, and the light emission stop signal generation unit 4 sets the determined dimming amount (reference voltage) with the variable voltage source (step S4).
Next, the CPU 11 causes the flash unit 2 to emit light by executing the light emission control program 13a (step S5). At this time, the comparator of the light emission stop signal generation unit 4 waits for the comparison circuit of the light emission stop signal generation unit 4 to reach a predetermined light control amount (reference voltage). Next, the CPU 11 determines whether or not the capacitor of the flash unit 2 has reached a predetermined light control amount based on the comparison result of the comparator (step S6). Here, when the CPU 11 determines that the capacitor of the flash unit 2 has reached a predetermined light control amount (step S6; YES), the light emission stop signal generation unit 4 sends the generated light emission stop signal to the flash unit 2. Then, the emission is stopped (step S7), and this process is terminated. On the other hand, when the CPU 11 determines that the capacitor of the flash unit 2 has not reached the predetermined dimming amount (step S6; NO), the CPU 11 returns to step S6 again, and the capacitor of the flash unit 2 has the predetermined dimming amount. The determination in step S6 is repeated until it is determined that it has been reached.

  If the CPU 11 determines in step S8 that the signal indicating that the telephoto mode has been selected has not been received (step S8; NO), the CPU 11 ends the process.

  According to the digital camera 100 in the present embodiment, the CPU 11 executes the first dimming amount determination program 13b, so that the strobe unit 2 is controlled based on the aperture value of the photographing lens 51 and the aperture value of the finder lens 52. Since the light control amount for controlling the light emission amount is determined, it is possible to eliminate the difference in aperture value change during zooming of the photographing lens 51 and the finder lens 52. Therefore, when the light receiving unit 3 is provided in the finder lens 52 having an optical system independent from the photographing lens 51, the light emission amount of the flash unit 2 can be controlled appropriately.

  Further, since the dimming amount corresponding to the combination of the aperture value of the photographing lens 51 and the aperture value of the finder lens 52 is stored in the storage unit 7, the CPU 11 executes the first dimming amount determination program 13b. As a result, the light control amount can be determined simply by setting the aperture value at each focal length from the storage unit 7, so that the light emission amount of the flash unit 2 can be appropriately controlled by a simple method.

  Note that the present invention is not limited to the above-described embodiment. For example, in the dimming amount determination process, the CPU 11 replaces the first dimming amount determination program 13b with the second dimming amount determination program 13c. By executing this, the CPU 11 first adjusts the light control amount corresponding to the combination of the aperture value of the photographic lens 51 and the aperture value of the finder lens 52 based on the aperture value of the photographic lens 51 and the aperture value of the finder lens 52. It may be calculated. In this case, the transmission timing of the light emission stop signal transmitted to the flash unit 2 is adjusted based on the calculated light control amount. As a result, the amount of light control can be determined simply by setting the aperture value of each lens in advance, so that the amount of light emitted from the flash unit 2 can be appropriately controlled by a simple method. Further, the digital camera 100 according to the present embodiment includes the first dimming amount determination program 13b and the second dimming amount determination program 13c. However, any one of the programs may be included. . Further, an aperture mechanism may be provided in the optical path of the taking lens 51, the finder lens 52, etc. so that the aperture value can be arbitrarily set. Further, in the detection of the integrated voltage, a detection unit that detects whether or not the reference voltage has been reached may be provided in the CPU 11 in advance. In addition, the present invention can be freely changed and improved without departing from the gist of the invention.

It is a block diagram which shows the principal part structure of a digital camera. It is a figure which shows the internal structure of a memory | storage part. It is a flowchart which shows the determination process of the light emission amount of a flash part.

Explanation of symbols

1 Control unit (dimming control means)
2 Flash unit (light emission means)
3 Light receiving part (light receiving means)
4 Light emission stop signal generator (dimming means)
7 Storage unit (storage means)
51 Shooting Lens 52 Viewfinder Lens 100 Digital Camera

Claims (3)

A light emitting means for emitting light toward a subject; a light receiving means for receiving light emitted from the light emitting means and reflected by the subject; and the amount of light received by the light receiving means reaches a predetermined light control amount. A light control unit that performs control to stop light emission by the light emitting unit, and includes a photographic lens and a finder lens having an optical system independent of the photographic lens, and the light receiving unit is provided in the finder lens. A digital camera,
A digital camera comprising a dimming amount determining means for determining the dimming amount based on an aperture value of the photographing lens and an aperture value of the finder lens. Storage means for storing a light control amount corresponding to a combination of the aperture value of the photographing lens and the aperture value of the finder lens;
The dimming amount determination unit corresponds to a combination of the aperture value of the photographic lens and the aperture value of the finder lens from the storage unit based on the set aperture value of the photographic lens and the aperture value of the finder lens. The digital camera according to claim 1, wherein the light control amount is extracted and determined.   The dimming amount determining means determines a dimming amount corresponding to a combination of the aperture value of the photographic lens and the aperture value of the finder lens based on the set aperture value of the photographic lens and the aperture value of the finder lens. The digital camera according to claim 1, wherein the digital camera is determined by calculation.

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