JP2003274279A - Camera having electronic preview function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera having electronic preview function in which a short-term consumption of a built-in battery due to modeling light emission can be prevented, in a camera having electronic preview function which is capable of modeling light emission for confirming a strobo effect on a subject. <P>SOLUTION: The camera having an electronic preview function is provided with an image pickup means 2 for imaging a subject, a strobo light emission means 4 for casting a strobo light to the subject, a quantity of light emission setting means for setting the quantity of light emission smaller than an adequate quantity of light emission to the strobo light emission means, an imaging control means for controlling the imaging operation of the imaging means and light emission operation of the strobo light emission means during the imaging operation, an image processing means 3 for adjusting the brightness of an image acquired by the imaging means, and a display means 7 for displaying an electronic image whose brightness is adjusted by the image processing means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having an electronic preview function, and more particularly to a camera having an electronic preview function capable of confirming a flash effect.

[0002]

2. Description of the Related Art Conventionally, a "strobe effect" for a subject
A silver halide camera having a strobe device capable of "modeling light emission" for confirming in advance is well known, and the strobe device is disclosed in, for example, JP-A-7-120812. In this modeling light emission, high-frequency multi-light emission is performed for several seconds, during which the shadow produced by the strobe light is visually confirmed. However, since the light emission form is different from that at the time of actual photographing, there is a problem that only simple confirmation is possible.

On the other hand, in a so-called digital camera in which a subject is imaged by an image sensor and stored in a memory device,
In many cases, the captured image can be displayed on a display device such as a liquid crystal monitor arranged on the back surface of the camera body (electronic preview function). With a digital camera that has this electronic preview function, you can check the direction and size of the shadow, or the ratio of ambient light and strobe light, etc., on the spot on the monitor screen provided on the camera. And, if there is a problem in the captured image,
If the photographer does not like it, the image capturing operation can be redone, and as a result, the number of failed photographs when using the flash can be reduced.

[0004]

However, if the image pickup operation is repeated many times in order to obtain the optimum strobe effect, the built-in battery for strobe charging may be consumed for a short period of time. .

An object of the present invention is to provide an electronic preview function capable of preventing short-term consumption of a built-in battery due to modeling light emission in a camera having an electronic preview function capable of modeling light emission for confirming a strobe effect on a subject. There is a camera provided.

[0006]

In order to achieve the above-mentioned object, a camera having an electronic preview function according to the present invention comprises an image pickup means for picking up an object and a strobe light for irradiating the object with strobe light. A light emitting means, a light emission amount setting means for setting a light emission amount smaller than an appropriate light emission amount for the strobe light emitting means, an image capturing operation of the image capturing means, and a light emitting operation of the strobe light emitting means during the image capturing operation. And an image processing unit that adjusts the brightness of the image acquired by the imaging unit, and a display unit that displays the electronic image whose brightness is adjusted by the image processing unit. In addition, the exposure control amount of the image pickup unit is shifted to the under side according to the light emission amount set in the strobe light emitting unit.

Further, in a camera having an electronic preview function of picking up an image of a subject prior to the main photographing operation and displaying the electronic image on a monitor screen, when executing the electronic preview operation, the exposure amount is below the proper exposure amount. It is characterized in that an image is taken with an exposure amount that becomes, and the brightness of the display image is adjusted by image processing before being displayed on the monitor screen.

Further, a camera having an electronic preview function according to the present invention is provided in the photographing lens, a photographing lens, an image pickup means for receiving a subject light flux through the photographing lens and outputting an electronic image of the subject. A diaphragm mechanism for limiting the luminous flux of the subject, strobe light emitting means for irradiating strobe light toward the subject, photometric means for outputting luminance information of the subject, and distance measuring for outputting distance information to the subject. Means, an appropriate exposure value setting means for setting an appropriate exposure value of the image pickup means from a combination of an aperture value of the diaphragm mechanism and an electronic shirt speed of the image pickup means on the basis of the brightness information, and the distance information. On the basis of,
A light emission amount setting means for setting the light emission amount of the strobe light emitting means, a light emission amount of the strobe light emitting means, and a proper exposure value of the image pickup means are respectively shifted to a lower side by a predetermined amount to calculate correction values. A correction unit, an image pickup control unit that operates the image pickup unit and the stroboscopic light emitting unit based on the correction value, and obtains an electronic image that is underexposed by a predetermined amount from the proper exposure; and an electronic image that is underexposed. Image processing means for adjusting the brightness corresponding to the proper exposure, and a display means for displaying the electronic image processed by the image processing means.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the illustrated examples. FIG. 1 is a perspective view of a camera having an electronic preview function according to a first embodiment of the present invention as seen from diagonally above and to the front right and FIG. 2 is a rear view.
The camera shown in FIG. 1 is a so-called digital camera in which a subject is imaged by an image sensor and stored in a memory element, and is composed of a camera body 100 and an external strobe device 200.

A hot shoe 105a for mounting the external strobe device 200 is provided on the upper surface of the pentaprism cover portion 105 at the center of the upper part of the camera body 100, and the external strobe device 200 can be detachably attached thereto. Is attached to. The hot shoe 105a is provided with a plurality of communication contacts, and control signals such as a light emission instruction signal and a light emission completion signal are transmitted between the camera body 100 and the external strobe device 200 via the contacts. Will be exchanged.

A rotary dial 10 is provided on the upper left side portion (in FIG. 1) of the camera body 100 to set the operating state of the camera to "photographable state" and "energy saving stop state".
3 are provided. The dial 103 is provided with a protrusion instruction portion 103a, and the photographer can use the instruction portion 10a.
When the rotating operation is performed so that 3a is aligned with the character "ON" printed on the outer surface of the upper surface of the camera body 100, power is supplied from an internal battery to an electric circuit (not shown) in the camera body 100. The camera body 100 is in the “photographable state”. In addition, the above-mentioned instruction unit 103a is set to “OF
If you rotate to match the letter "F" (off),
The power supply to the electric circuit is cut off, and the "energy saving stop state" is entered. This energy-saving stop state is the camera body 10
The power is supplied only to the minimum necessary portion of the electric circuit system in 0, and the camera does not operate at all in this state.

A grip portion 101 for a photographer to grip the camera body 100 is provided in a protruding manner on the left front part (in FIG. 1) of the camera body 100, and a release button 102 is arranged on the upper surface thereof. ing.

A modeling shooting instruction button 104 for performing a modeling shooting operation is arranged at the center of the rotary dial 103. The modeling shooting operation is an operation of performing a simulated shooting operation prior to the main shooting operation (the shooting operation and the image data storage operation) to confirm the image obtained by the main shooting operation in advance.
At this point, you can check the flash effect during actual shooting by firing the flash.

The photographer uses the modeling photographing instruction button 104.
When performing a modeling shooting operation by operating, the strobe light is emitted from the light emission window 201 of the external strobe device 200 and the stroboscopic shooting is performed when the brightness of the subject is low. Then, the captured subject image is displayed on a liquid crystal display screen (hereinafter referred to as a monitor screen) 106 provided on the back surface of the camera body 100 shown in FIG.

Therefore, the photographer can confirm the lighting condition for the subject, the exposure setting value, the strobe effect (the degree of the shadow, the balance with the external light), etc. by looking at the image on the monitor screen. It should be noted that the image taken at the time of modeling shooting is not stored in the memory element, and is displayed on the monitor screen 1
Only confirmation at 06 is made.

FIG. 3 is a block diagram showing the configuration of an electric circuit of a camera having an electronic preview function. As described above, the camera body 100 and the external strobe device 200 are connected by the hot shoe 105a.

In the camera body 100, there is provided a sequence control unit 1 which is composed of a CPU and controls the overall operation sequence.
When 3 is operated to the "ON" position, it closes and "OFF"
Power switch (switch) 1 that opens when operated to the position
2 and 1 by pressing the release button 102 halfway
The st. release SW 13, the 2nd. release SW 14 that is closed by pressing the release button 102 deeply, and the modeling SW 15 that is closed by pressing the modeling shooting instruction button 104 are connected. The sequence control unit 1 also includes an image processing unit 3 for performing image processing of an image signal from an image pickup unit (image pickup device) 2 including a CCD for picking up an image of a subject, and detection of a focus state of a taking lens 9. Focus state detection unit 18 for performing an external flash device 2
The light emission control units 5 in 00 are also connected.

Then, the sequence control unit 1 forms a subject image on the image pickup surface of the image pickup unit 2 by a photographing lens 9
And a diaphragm mechanism 10 that operates to limit the light flux of the subject.
And a shutter mechanism 11 provided immediately before the image pickup surface of the image pickup unit 2 and configured to open and close the image pickup light flux by a plurality of blade members, and image pickup so that the object light flux is guided to a finder optical system (not shown) during object observation. A movable mirror 16 that enters the optical path and retracts outside the optical path during shooting, and a subject light flux that is attached to the central rear surface of the movable mirror 16 and that has passed through the half mirror section of the central part of the movable mirror 16 detects the focus state. A sub-mirror 17 that reflects so as to be guided to a section 18 (described later) and a plurality of photoelectric conversions that receive the subject light flux reflected by the sub-mirror 17 and detect the focus state of the taking lens 9 using a known phase difference method. It is composed of a line sensor using an element, based on the integrated amount of this photoelectric conversion element,
The focus state detection unit 18 that also detects the brightness distribution of the subject
And controlling the image pickup unit 2 to perform an image pickup operation,
Control signals are issued to the image processing unit 3 that processes the image signals picked up by the image pickup unit 2 to control them.

Here, the image processing unit 3 controlled by the sequence control unit 1 responds to an instruction from the image processing unit 3 and stores an image storage unit 8 for storing the image data processed by the image processing unit 3. And an image display unit 7 for displaying a subject image captured during modeling.

Further, the external strobe device 200 mounted on the camera body 100 is controlled by the sequence control unit 1 in the camera body 100 via a plurality of communication contacts of the hot shoe 105a (for example, a light emission instruction signal or a light emission instruction signal). A light emission completion signal, etc.) is sent.

The external strobe device 200 is xe
In response to a control signal from a light emitting unit 4 configured to irradiate a subject with strobe light, a charge control unit 6 that operates to store a light emitting charge in a built-in main capacitor, and a sequence control unit 1 Then, the light-emission control unit 5 and the like are caused to perform the light-emission operation by causing the charge accumulated in the capacitor to flow into the xe tube. This strobe device 2
The light emission amount of 00 is set based on the light emission guide number information instructed by the sequence control unit 1.

The sequence control unit 1 includes a photographing lens 9
Has the function of calculating the subject distance from the amount of extension from that position as the drive reference position, and the subject distance information obtained by this method is used when calculating the flash emission amount (flash guide number). Used. Also,
The strobe device contains a battery different from the above-mentioned battery.

FIG. 4 is a block diagram showing a configuration of an electric circuit of the image processing unit 3 and peripheral circuits related thereto. As described above, the image pickup unit 2a in the image pickup unit 2, the image display unit 7, and the image storage unit 8 are connected to the image processing unit 3, respectively.

Inside the image processing section 3, a CPU 20 for controlling the signal processing operation is arranged.
Includes a pre-processing circuit 21 and a thinning / extraction processing circuit 22.
A simple post-processing circuit 23, a video decoder 24,
A WB (White Balance) processing circuit 25,
Post-stage processing circuit 26 and JPEG compression / expansion processing circuit 27
Are connected to each other and operate according to a control signal from the CPU 20. Also, C
The PU 20 is connected to the sequence control unit 1 via a communication line 40, and controls each circuit in the image processing unit 3 based on the control signal transmitted from the sequence control unit 1.

Image pickup device 2a outside the image processing unit 3
The (corresponding to the image pickup unit 2 in FIG. 3) is connected to the pre-stage processing circuit 21, picks up an image of a subject according to the driving conditions set by the CPU 20, and outputs a subject image signal to the pre-stage processing circuit 21.

The pre-processing circuit 21 A / D converts the analog video signal output from the image pickup device 2a to generate a digital image signal. In addition, the image signal is corrected based on the pixel signal of the light-shielded portion of the image sensor 2 a, and the digital image signal is output to the thinning / extraction processing circuit 22.

The decimation / extraction processing circuit 22 is a circuit for decimation processing (processing for reducing resolution) of the digital image signal output from the pre-stage processing circuit 21. However, the thinning process is not performed on the image signal output to the post-stage processing circuit 26, and the thinning process is performed only on the digital image signal output to the simple post-stage processing circuit 23. This is because image data used only for image display does not need to have high resolution, and there is no problem even if thinning processing is performed according to the display capability of the LCD monitor 29 in the image display unit 7. Is. Moreover, since the processing data is drastically reduced by performing the thinning-out processing, there is an advantage that the image processing time can be shortened.

Therefore, in the modeling photographing operation, this thinning-out processing is performed in the thinning-out / extracting processing circuit 22. The degree of thinning of the image signal output to the simple post-stage processing circuit 23 is instructed by the CPU 20 according to the resolution suitable for image display.

The thinning / extracting processing circuit 22 extracts a part of the digital image signal to extract the WB processing circuit 2.
Output to 5. The WB processing circuit 25 is a circuit that outputs white balance information (WB information) for adjusting the color balance (white balance) of the image. This WB information is directly sent to the simple post-stage processing circuit 23, and the post-stage processing circuit Two
6 is sent to CPU 6 via CPU 20.

The simple post-stage processing circuit 23 is a circuit for generating an image to be displayed on the LCD monitor 29 in the image display section 7.
It works only during modeling shooting. Here, image brightness correction, γ correction, reduction of the number of image signal data bits, color adjustment based on WB information, RGB signal to YCbC
Well-known processing such as conversion into an r signal is performed. Generally, LC
In order to display the picked-up image on the D monitor 29, the processing speed by software becomes slow, so that all the image processing for display is performed by the simple post-processing circuit 23 by hardware. ing. Also, since the brightness of the image is below the proper value during modeling shooting, brightness adjustment is important.

By the way, in the camera of the first embodiment, as described above, the "imaging mode" in which a general imaging operation (main imaging operation) is performed, and what kind of image is obtained before the actual imaging operation is actually performed? The "modeling mode" for confirming whether or not is imaged can be selected, and the image processing operation by the simple post-stage processing circuit 23 is an operation performed only in this modeling mode.

The video decoder 24 is a circuit for converting a YCbCr signal into an NTSC signal. The converted signal is sent to the LCD drive circuit 28 of the image display unit 7, and LC
It is displayed on the LCD monitor 29 under the control of the D drive circuit 28.

The post-stage processing circuit 26 is a circuit for generating an image signal to be stored in the flash memory 32. The image brightness correction, γ correction, reduction of the number of data bits of the image signal, color adjustment based on WB information. , Known signals such as conversion from RGB signals to YCbCr signals, defective pixel correction of the image sensor 2a, smear correction, HUE and Croma (color tone adjustment processing) are performed.

The JPEG compression (compresses the data file in the JPEG format) / expansion processing circuit 27 stores the image signal processed by the post-processing circuit 26 in the flash memory 32 in the image storage unit 8 in the JPEG format. JPE compressed in the format or stored in the flash memory 32
This is a circuit for reading out and expanding the G image.

5 and 6 are flow charts for explaining the entire sequence of the digital camera having the electronic preview function, focusing on the operation of the sequence controller 1.
When a power supply battery is loaded in the camera body 100, the camera starts the operation by the power-on reset function. After starting by power-on reset, immediately after that, in step S10, a power switch (hereinafter referred to as power SW) 1
Check condition 2. Here, if the power SW is OFF, the process proceeds to step S20, the camera is in the energy saving state as it is, and the operation is stopped. In this state, a part of the functions of the sequence control unit 1 (the power SW is OFF to
The power supply is shut off except for the function of checking whether or not it has changed to N). Therefore, the power consumption of the entire camera is minimized. When the photographer operates the turning dial 103 to turn on the power SW, the sequence control unit 1 detects the change and is activated, and sets all circuits in the camera including other functional parts to the operating state.

In step S10, the power source SW1
If 2 is ON, or if the energy saving state of step S20 has been restored, the process proceeds to step S30, and 1
st. It is checked whether or not the release SW 13 is ON, that is, whether or not the photographer half-presses the release button 102.

If it is not turned on here, step S23
0, the modeling SW is turned on, that is, it is checked whether or not the photographer is pressing the modeling shooting instruction button 104. If not, the process returns to step S30 and is turned on.
If so, the process proceeds to step S240, and the modeling operation is performed thereafter.

In this modeling operation, first, the photographing lens 9 is driven to the in-focus position based on the information regarding the focus state of the photographing lens 9 sent from the focus state detection unit 18. At this time, the subject distance is obtained from the in-focus position of the taking lens 9. (This operation is the same as the operation of step S40 described later).

Next, in step S250, the focus state detection unit 1
Based on the information on the subject brightness distribution sent from 8,
Using a predetermined exposure calculation formula, the electronic shutter speed and aperture value for obtaining the proper exposure amount are calculated, and then step S
In 260, the flash emission amount is obtained by flashmatic calculation based on the aperture value calculated in step S250 and the subject distance information based on the extension amount of the taking lens 9.

In the case of modeling photography, it is wasteful of energy to irradiate the same amount of strobe light as in photography, and the recharging time thereafter becomes long. Therefore, in the next step S270, light emission amount information obtained by halving the appropriate strobe light emission amount calculated in step S260, that is,
The correction calculation is performed so that the guide number information is under two steps when expressed by the apex calculation value. However, when the amount of strobe light decreases, the balance between strobe light and ambient light (natural light) is lost, so the main subject is under
The surroundings are appropriate. Therefore, the integration time (electronic shutter speed) of the image sensor and the aperture value of the aperture mechanism 10 are also corrected so as to be under by two steps.
By the correction, the balance between the two can be secured, and the same strobe effect as in actual shooting can be obtained. At this time, if the change in the depth of field due to the change in the aperture value is prevented from occurring, only the electronic shutter speed needs to be corrected.

Next, the electronic shutter speed information corrected and calculated in step S270 is transmitted to the image processing section 3 in step S280. The image processing unit 3 sets the imaging time (integration time) of the imaging unit 2 based on this information.

Next, the light emission amount information corrected and calculated in step S270 is stored in the flash device 2 in step S290.
00 is transmitted to the light emission control unit 5, and further step S30
At 0, the movable mirror 16 and the sub mirror 17 are retracted out of the optical path of the photographing as the first step of the photographing operation (mirror up operation).

Then, the aperture mechanism 10 is driven in step S310 to the aperture value calculated in step S250, the shutter 11 is opened in step S320, and step S3 is performed.
At 30, the built-in timer counter for detecting the strobe light emission timing is started. At the same time, a signal for instructing the start of the modeling imaging operation is transmitted to the image processing unit 3 in step S340. Image processing unit 3
Performs a modeling shooting operation if the received instruction signal is a signal for instructing modeling shooting.

After the modeling photographing operation is executed, step S3
At 50, it is checked whether or not the image pickup completion signal is transmitted from the image processing unit 3. Here, if there is no imaging completion signal, the process proceeds to step S360, and it is determined whether or not the built-in timer counter, which has started the time counting in step S330, reaches a predetermined value, and if it does not reach the predetermined value, step S350.
If it is reached, the process proceeds to step S370, and a signal for instructing the flash emission is transmitted to the flash control unit 5 of the flash device 200. Receiving this signal, the light emission control unit 5 controls the light emission unit 4 to irradiate the strobe light based on the already received light emission amount information.

When the image pickup completion signal is received from the image processing unit 3 in step S350, the next step S3 is performed.
The shutter 11 is controlled to be closed at 80, and step S3
At 90, the aperture mechanism 10 is returned to the open state, and step S40
At 0, the movable mirror 16 and the sub mirror 17 are returned to the shooting optical path. Further, in step S410, the image processing unit 3 is instructed to display the captured image, and the process returns to step S10.

Upon receiving this instruction, the image processing section 3 displays the modeled photographed image on the image display section 7. It should be noted that the image captured by the modeling shooting is only displayed and is not stored in the flash memory 32.

On the other hand, if the 1st release SW 13 is turned on in step S30, that is, if the photographer half-presses the release button 102, step S4
The process proceeds to 0, and the photographing lens 9 is driven to the in-focus position based on the information on the focal state of the photographing lens 9 sent from the focus state detection unit 18. At this time, the subject distance is obtained from the in-focus position of the taking lens 9.

Next, in step S50, the information about the subject brightness distribution sent from the focus state detecting section 18 is obtained, and an appropriate exposure amount is obtained by using a predetermined exposure calculation formula (electronic subject speed at the image pickup section 2). The time when the image is actually integrated) and the aperture value of the aperture mechanism 10 are calculated. Then, in step S60, the calculated aperture value and the photographing lens 9
The flash emission amount (guide number information) is obtained by flashmatic calculation by using the subject distance information based on the extension amount of.

Next, in step S70, it is checked whether or not the second release SW14 is ON, that is, whether or not the photographer has deeply pressed the release button 102. O
If not, it is checked again in step S220 whether or not the 1st. Release SW 13 is ON, that is, whether or not the photographer has half-pressed the release button 102. If it is ON, the process returns to step S70,
If it is not turned on, the process returns to step S10.

If the second release SW 14 is turned on in step S70, the above step S50 is performed.
Imaging time information calculated by (electronic shutter speed information)
Is transmitted to the image processing unit 3 in step S80. The image processing unit 3 sets the imaging time (integration time) of the imaging unit 2 based on this information.

Next, the strobe light emission amount information corrected and calculated in step S60 is transmitted to the light emission control section 5 of the strobe device 200 in step S90, and further in step S90.
In 100, the movable mirror 16 is used as the first step of the photographing operation.
Also, the sub-mirror 17 is retracted out of the photographing optical path (mirror up operation).

Then, in step S110, the aperture mechanism 10 is driven to the aperture value calculated in step S50,
Next, in step S120, the shutter 11 is opened,
In step S130, a built-in timer counter for detecting the strobe light emission timing is started. Next, in step S140, a signal instructing the start of the imaging operation is transmitted to the image processing unit 3. Upon receiving this signal, the image processing unit 3 controls the image capturing unit 2 to start the image capturing operation, and terminates the image capturing operation when the time corresponding to the electronic shutter speed instructed in step S80 has elapsed. And
When the image pickup operation is completed, an “image pickup completion signal” is returned to the sequence control unit 1.

Next, after executing the photographing operation, it is checked in step S15 whether the image pickup completion signal is transmitted from the image processing section 3.
Check with 0. Here, if there is no imaging completion signal,
In step S160, it is determined whether or not the built-in timer counter, which has started time counting in step S130, has reached a predetermined value. If the predetermined value has not been reached, the process returns to step S150, and if it has, the process proceeds to step S170. The predetermined value is, for example, a camera shake limit value (a time value at which the effect of the camera shake on the image quality is large). When the predetermined value is reached, a signal for instructing the flash emission is transmitted to the flash control unit 5 of the flash device 200. Receiving this signal, the light emission control unit 5 controls the light emission unit 4 to irradiate the strobe light based on the already received light emission amount information.

The irradiation of the strobe light is performed before the integration time described above has elapsed, that is, while the image pickup unit 2 is executing the integration operation.

When the image pickup completion signal from the image processing unit 3 is received in step S150, the shutter 11 is controlled to be closed in step S180, the diaphragm mechanism 10 is returned to the open state in step S190, and the movable mirror is moved in step S200. 16 and the sub-mirror 17 are returned to the shooting optical path, and in step S210, the image processing unit 3
It is instructed to store the imaged image data in the image storage unit 8. In response to this instruction, the image processing unit 3 reads the image pickup signal from the image pickup unit 2, performs a predetermined process, and then stores the image data in the image storage unit 8. Then, when the storage operation is completed, the sequence control unit 1 is notified of that fact. When the storage operation is completed, the sequence control unit 1 executes the operation after step S10 again.

FIG. 7 shows a CPU incorporated in the image processing section 3.
It is a flowchart which shows operation | movement of 20. This CPU2
When 0 is supplied with power, a power-on reset is applied to start operation. First, in step S490, after the operation is started, a state waiting for an instruction signal from the sequence control unit 1, that is, a “standby state” is set.

If there is an instruction signal in the standby state of step S490, the process returns from the standby state and proceeds to step S500. Then, it is checked whether or not the instruction signal is a communication request signal.

If the instruction signal is a communication request signal, step S
In step 620, communication processing for receiving the electronic shutter speed information and the like transmitted from the sequence controller 1 is performed, and the process returns to the standby state of step S490. If it is not a communication request signal, the process advances to step S510 to check whether it is an instruction to perform a normal photographing operation. If it is the instruction of the normal image capturing operation, the process proceeds to step S600, and the image capturing element 2a is instructed to start and stop the image capturing to execute the image capturing operation. The imaging time (integration time) is determined based on the electronic shutter speed value transmitted from the sequence controller 1. When the imaging operation is completed, an “imaging completion signal” is transmitted to the sequence controller 1 in step S610, and the pre-stage processing circuit 21, the thinning / extraction processing circuit 22,
The WB processing circuit 25, the post-stage processing circuit 26, and the JPEG compression / expansion processing circuit 27 are controlled to execute the above-described image processing operation. Here, the processed image data is temporarily S
It is held in the DRAM 31. Although this image data passes through the thinning / extracting processing circuit 22, the thinning processing is not performed.

If it is not the instruction of the normal photographing operation in step S510, the process proceeds to step S520, and it is checked whether it is the instruction of modeling photographing. If the instruction is for modeling shooting, the process proceeds to step S580,
The image pickup device 2a is instructed to start and stop the image pickup, and the image pickup operation is executed. The image capturing time (integration time) is determined based on the electronic shutter speed value transmitted from the sequence control unit 1. When the image capturing operation is completed in the same manner as in step S600, the sequence control unit 1 performs "image capturing" in step S590. A completion signal "is transmitted to control the pre-stage processing circuit 21, the thinning-out / extracting processing circuit 22, the WB processing circuit 25, and the simple post-stage processing circuit 23 to execute the image processing operation suitable for the image display during the modeling shooting. Since the image at the time of modeling photography is so-called underexposure that is shifted to the underside of the proper exposure amount, the acquired image cannot be displayed correctly unless the brightness of the image is properly adjusted.
Therefore, the brightness distribution of the image is analyzed, and the overall brightness information bottom-up processing is performed. Alternatively, when the amount of underexposure is clear, the brightness may be adjusted according to the amount. Since the processed image data has a small data capacity, it is temporarily held in the memory area in the simple post-processing circuit 23, and compression processing and storage in the non-volatile memory element are not performed. Therefore, there is an advantage that the processing time is short.

In step S520, if it is not the instruction of modeling photography, the process proceeds to step S530, and it is checked whether or not the signal is an image storage instruction. If it is an image storage instruction, the process proceeds to step S560, and the image data temporarily stored in the SDRAM 31 in step S610 is read. Then, the read image data is stored in a predetermined storage area of the flash memory 32 in step S570.

If it is not an image storage instruction in step S530, the flow advances to step S540 to check whether the image display instruction is issued. If it is an image display instruction, the process proceeds to step (S550) to instruct the simple post-stage processing circuit 23 to output the image data temporarily stored in the internal memory area to the video decoder 24, and the process proceeds to step S555. . Then, the video decoder 24 is instructed to convert the input image data and output it to the LCD drive circuit 28. On the other hand, in step S540, if there is no image display instruction, no operation is performed and the process returns to step S500.

Here, to summarize the configuration of the essential parts of the digital camera of the first embodiment described so far, this digital camera receives the subject light flux through the taking lens 9 and the taking lens 9. An image pickup unit (image pickup unit 2) that outputs an electronic image signal of the subject, a diaphragm mechanism 10 that is provided in the photographing lens and limits the light flux of the subject, and a strobe light emitting unit that irradiates strobe light toward the subject. (Strobe device 200), photometric means for outputting the luminance information of the subject (luminance distribution detecting function of the focus state detecting section 18), and distance measuring means for outputting distance information to the subject (of the focus state detecting section 18). The focus state detection function and the subject distance calculation function of the sequence control unit 1), and the aperture value of the aperture mechanism and the electronic shutter shutter of the image pickup means based on the brightness information. Over de combined from the correct exposure value appropriate exposure value setting means for setting a (some functions of the sequence control unit 1, step 250 of FIG. 5) of the imaging means and,
A light emission amount setting means (a partial function of the sequence control unit 1, step 260 in FIG. 5) for setting the light emission amount of the strobe light emitting means based on the distance information, the light emission amount of the strobe light emitting means, and Based on the correction means (a partial function of the sequence control unit 1, step S270 in FIG. 5) for calculating a correction value obtained by shifting the proper exposure value of the image pickup means to the under side by a predetermined amount, and based on the correction value, An image pickup control unit that operates the image pickup unit and the strobe light emitting unit to obtain an electronic image that is underexposed by a predetermined amount from the proper exposure (partial function of the sequence control unit 1, steps S300 to S6 in FIG. 5). S400), image processing means (image processing unit 3) for performing image processing on the underexposed electronic image, and adjusting to a brightness corresponding to appropriate exposure; A digital camera having an electronic preview function comprising display means for displaying the electronic image processed by the image processing unit (image display unit 7), the.

According to the digital camera configured as described above, it is possible to confirm the photographed image by modeling photographing in advance. When using a strobe during modeling, the strobe emission amount (guide number) is reduced by a predetermined amount compared to during actual photography, which saves the light emission charge stored in the main condenser of the strobe. It is possible to shorten the charging time for subsequent actual shooting. Since the amount of recharge is small, it is possible to suppress battery consumption.

However, if the amount of strobe light is reduced,
The balance between ambient light (natural light) and strobe light is different from when shooting. Therefore, as the amount of strobe light emission decreases, the combination of the diaphragm and electronic shutter is shifted to the under side by a predetermined amount (the same amount as the decrease in strobe light) to reduce the effect of ambient light, and I try to keep the balance of light.

Further, in this case, the proper exposure amount cannot be obtained with both strobe light and ambient light, and the photographed image is underexposed and becomes a dark image. Therefore, in the present invention, after the image pickup operation is completed, the CPU 20 causes the pre-stage processing circuit 21,
The thinning / extracting processing circuit 22, the WB processing circuit 25, and the simple post-stage processing circuit 23 are controlled to perform image correction processing before displaying. Therefore, it is possible to confirm the same flash effect for the subject as in the actual shooting.

Further, at the time of modeling photographing, the thinning / extracting processing circuit 22 thins the picked-up images, so that the display operation can be executed at high speed. As a result, it is possible to shorten the image processing waiting time as in the case of actual shooting.

Further, since the image storage operation is not performed during the modeling shooting and only one display is performed, the image storage waiting time unlike in the actual shooting does not occur, so that the display can be performed at high speed.

In the first embodiment, the underexposure is controlled even when the strobe is not used.
As a practical matter, if the strobe light is not emitted, the above-mentioned various problems do not occur, but there is an advantage that the imaging time is shortened if the exposure is underexposed even when the strobe is not used.

Of course, the present invention can be applied not only to a single-lens reflex type digital camera, but also to a compact type digital camera and a camera using a silver salt film.

FIG. 8 is a block diagram of an electric circuit of a silver salt film camera having an electronic preview function according to the second embodiment of the present invention.

The electric circuit configuration of the silver halide camera having the electronic preview function of the second embodiment is almost the same as that of the camera circuit of the camera having the electronic preview function of the first embodiment shown in FIG. Although the same, this camera uses a silver salt film, and therefore the silver salt film 5 is provided behind the shutter mechanism 11 instead of the image sensor.
1 is arranged, and the image pickup section 2, the image processing section 3, and the image display section 7 are arranged on the strobe device 200 side. Further, since this camera is a silver salt film camera, an image storage unit for storing the image captured by the image capturing unit 2 is unnecessary and omitted.

Therefore, only this difference will be described, the same components as those of the electric circuit of the camera having the electronic preview function of the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

In the electric circuit of the silver halide camera having the electronic preview function of the second embodiment, an image pickup optical system 50 having a fixed focal length is newly provided in order to guide the subject light image to the image pickup section 2. The optical axis of the imaging optical system 50 is set so as to completely cover the screen of the silver salt film 51 at a finite distance (for example, 3 mm). further,
A fixed diaphragm mechanism 52 is arranged between the image pickup optical system 50 and the image pickup surface (not shown) of the image pickup section 2.

According to the second embodiment of the present invention having such a configuration, the operation of the sequence controller 1 is newly added with the exposure control to the silver salt film 51, but the other control is performed as described above. It is similar to the first embodiment.

That is, when the modeling SW is operated, the image pickup unit 2, the image processing unit 3, and the image display unit 7 are controlled without performing the exposure operation to the film, and the preliminary confirmation operation is executed to obtain the subject brightness. If the flash is low and strobe light is required, the strobe light emission amount (guide number) is reduced by a predetermined amount compared to the actual shooting, and the combination of the aperture and electronic shutter is set to the under side by the predetermined amount (same as the decrease in strobe light. (The amount is shifted) (however, in the second embodiment, since the diaphragm mechanism 52 is a fixed diaphragm, only the electronic shutter speed is actually corrected.) Underexposure is corrected when displaying an image. The image is corrected so that

As a result, modeling photography can be performed even with a silver halide camera, and the electronic flash function can be used to check the flash effect.

[0077]

As described above, according to the present invention, when the stroboscopic light is required for the modeling shooting, the strobe emission amount (guide number) is shifted to the underexposure side as compared with the actual shooting. Since it is possible to save the light emission charge of the strobe and to shorten the charging time for subsequent actual shooting, it is possible to suppress the consumption of the battery. Further, in that case, since the image correction processing is performed before displaying the image, it is possible to confirm the same flash effect for the subject as in the actual shooting. Further, since the picked-up images are thinned out at the time of modeling shooting, it is possible to provide a camera having an electronic preview function capable of reducing the image processing waiting time and performing a display operation at high speed.

[Brief description of drawings]

FIG. 1 is a perspective view of a camera having an electronic preview function to which the present invention is applied, as seen from a front upper right diagonal direction;

FIG. 2 is a rear view of the camera having the electronic preview function shown in FIG.

FIG. 3 is a block diagram showing a configuration of an electric circuit of a camera having an electronic preview function according to the first embodiment of the invention.

4 is a block diagram showing the image processing unit in FIG. 3 and peripheral circuits related thereto;

FIG. 5 is a flowchart explaining the entire sequence of a camera having an electronic preview function, focusing on the operation of the sequence control unit (No. 1).

FIG. 6 is a flowchart explaining the entire sequence of a camera having an electronic preview function, focusing on the operation of the sequence control unit (No. 2).

7 is a flowchart showing the operation of a CPU incorporated in the image processing unit shown in FIG. 3;

FIG. 8 is a block diagram showing a configuration of an electric circuit of a silver salt film camera having an electronic preview function according to a second embodiment of the present invention.

[Explanation of symbols]

100 ...- Camera main body 200 --- External strobe device 1 --- Sequence control unit 2--Imaging unit (imaging Means) 3 ... Image processing unit (image processing unit) 4 ... Emitting unit (strobe light emitting unit) 5 ... Emission control Section (strobe light emitting means) 7 ... Image display section (display means) 9 ... Shooting lens 10 ... Aperture mechanism 11 ...・ ・ ・ ・ Electronic shutter 15 ・ ・ ・ ・ ・ ・ Modeling SW 18 ・ ・ ・ ・ ・ ・ Focus state detector

Claims (4)

[Claims] 1. An image pickup unit for picking up an image of a subject, a strobe light emitting unit for irradiating strobe light toward the subject, and a light emission for setting a light emission amount smaller than an appropriate light emission amount for the strobe light emitting unit. Quantity setting means, image pickup control means for controlling the image pickup operation of the image pickup means, and the light emission operation of the strobe light emitting means during the image pickup operation, and image processing means for adjusting the brightness of the image acquired by the image pickup means And a display unit for displaying the electronic image whose brightness is adjusted by the image processing unit, and a camera having an electronic preview function. 2. The electronic preview according to claim 1, wherein the exposure control amount of the image pickup unit is shifted to the under side according to the strobe light emission amount set in the strobe light emission unit. A camera with functions. 3. A subject is imaged prior to the main photographing operation,
When performing an electronic preview operation in a camera that has an electronic preview function that displays the electronic image on the monitor screen, the exposure amount that is below the proper exposure amount is taken, and the brightness of the displayed image is processed by image processing. A camera having an electronic preview function, characterized in that it is displayed on the monitor screen after the height is adjusted. 4. A photographing lens, an imaging means for receiving a subject light flux through the photographing lens and outputting an electronic image of the subject, and a diaphragm mechanism provided in the photographing lens for limiting the subject light flux. Strobe light emitting means for irradiating the subject with strobe light, photometric means for outputting the luminance information of the subject, distance measuring means for outputting distance information to the subject, and based on the luminance information, A proper exposure value setting means for setting a proper exposure value of the image pickup means from a combination of the aperture value of the diaphragm mechanism and the electronic shutter speed of the image pickup means, and the light emission amount of the strobe light emitting means based on the distance information. A light emission amount setting means for setting, a light emission amount of the strobe light emitting means, and a proper exposure value of the image pickup means, which are shifted by a predetermined amount to the under side, respectively. Correction means for calculating, and an imaging control means for operating the imaging means and the stroboscopic light emitting means based on the correction value to obtain an electronic image underexposed by a predetermined amount from the proper exposure, and the underexposure. Image processing is applied to the electronic image of
A camera having an electronic preview function, comprising: an image processing unit that adjusts to a brightness corresponding to a proper exposure; and a display unit that displays an electronic image processed by the image processing unit.