JP4419284B2 - Flash-capable camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flash photography camera that shoots an object by using a flashlight as auxiliary illumination light.
[0002]
[Prior art]
2. Description of the Related Art A camera is known that takes a picture by automatically emitting a flashlight to illuminate the subject when the subject illuminated by natural light has low brightness. In this type of camera, the shutter speed is fixed at a relatively high speed for flash photography at low brightness to prevent image quality deterioration due to camera shake.
[0003]
[Problems to be solved by the invention]
However, with the above-mentioned camera, when a person is photographed against a night scene, the person is illuminated with a flashlight so that the exposure is appropriate, but the flashlight does not reach the distant night scene, and the shutter speed Is fixed at a fast speed, the background will be underexposed and in the worst case it may not be visible at all. If so-called slow sync photography is performed without fixing the shutter speed at a high speed, an image of a person or background may flow due to camera shake.
[0004]
An object of the present invention is to capture a background while preventing camera shake when photographing using a flashlight as auxiliary illumination light.
[0005]
[Means for Solving the Problems]
The present invention will be described with reference to FIG. 2 showing the relationship between the subject brightness Bv and the shutter speed Tv according to the embodiment.
(1) The invention of claim 1 includes a photometric unit for measuring subject luminance, and a control unit that calculates an exposure value based on the subject luminance measured by the photometric unit and controls the shutter and the light emitting unit, control unit, when flash photographing by causing the light emitting portion, if the first subject luminance Bv5 least corresponding to shutter speed limits subject luminance is prevented shake TV 5 serving (1/30 seconds), the subject When the shutter speed Tv is determined according to the decrease in the brightness Bv, and the subject brightness is between the first subject brightness Bv5 and the second subject brightness Bv3 that is underexposed by a predetermined exposure value 2EV, the shutter speed Tv were fixed to the limit of the shutter speed Tv5 to shake can be prevented (1/30 seconds), the shutter speed when the subject luminance is less than the second brightness value according to reduction of the subject brightness The above objective is achieved by slowing down the degree.
(2) In the camera capable of flash photography according to claim 2, the control unit sets a high shutter speed at which the exposure is underexposed by a predetermined exposure value when the subject brightness is equal to or lower than the second subject brightness. .
(3) In the camera capable of flash photography according to (3), the control unit makes a predetermined exposure value variable according to a photographing mode.
(4) flash camera capable of photographing according to claim 4, wherein the control unit, it is an arbitrarily variable predetermined exposure value.
(5) The camera capable of flash photography according to claim 5 is configured such that when the subject brightness is equal to or less than a third subject brightness that is underexposed by a predetermined exposure value from the second subject brightness, The shutter speed is fixed to a lower shutter speed than the limit shutter speed that can prevent the above .
(6) The camera capable of flash photography according to claim 6 is configured such that the control unit fixes the shutter speed to the maximum sync speed when the subject brightness is equal to or higher than the fourth subject brightness higher than the first subject brightness. is there.
[0006]
In the section of the means for solving the above-described problem, a diagram of an embodiment is used for easy understanding of the description. However, the present invention is not limited to the embodiment.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a single-lens reflex camera will be described. FIG. 1 shows the configuration of an embodiment. The camera according to the embodiment includes a photographing lens 1, an aperture 2, a quick return mirror 3, a shutter 4, a film 5, a focusing plate 6, a pentaprism 7, a photometric lens 8, a photometric light receiving element 9, and a flash light emitting unit 10. , A control device 11, a flashlight control device 12, and the like.
[0008]
The control device 11 is composed of peripheral components such as a microcomputer and a memory, calculates an exposure value based on the subject brightness measured by the photometric light-receiving element 9, and controls the aperture 2, the shutter 4, and the flash light control device 12. . The flash light control device 12 causes the light emitting unit 10 to emit light according to the light emission command received from the control device 11 of the camera body.
[0009]
FIG. 2 shows a control result of the shutter speed with respect to the subject brightness at the time of flash photographing with the flashlight according to the embodiment. In this embodiment, flash photography with a flashlight is automatically performed when low brightness, backlight conditions, or the like are detected based on the photometric result of the subject. The program diagram of the shutter speed at this time is shown in FIG.
[0010]
As described above, when a conventional camera capable of flash photography performs flash photography at low brightness, for example, as indicated by a broken line in FIG. 2, a high-speed shutter of Tv7 (1/125 seconds) regardless of subject brightness Bv. The shutter speed Tv is decreased according to the decrease in the subject brightness Bv until the shutter speed is fixed to the speed or, for example, the shutter speed reaches a limit that can prevent camera shake of Tv5 (1/30 seconds). In these cases, the diaphragm is fixed to, for example, Av5 (F5.6), which is used most frequently. However, if the flash is taken at a high shutter speed when the brightness is low, camera shake can be prevented, but the background such as a night view may become underexposed and may not be captured.
[0011]
On the other hand, when flash photography is performed under low brightness without fixing to a high shutter speed, so-called slow sync photography, the shutter speed Tv corresponds to a decrease in subject brightness Bv as shown by a thin solid line in FIG. Become slow. In this slow sync shooting, a background such as a night scene can be captured, but as the subject brightness Bv decreases, the shutter speed Tv decreases and a person or background image flows due to camera shake.
[0012]
Therefore, in this embodiment, the shutter speed Tv corresponding to the subject brightness Bv is set so that a background such as a night scene can be captured while preventing a camera shake when flash photography is performed under low brightness. Set.
[0013]
Specifically, when the subject brightness is Bv7 (Ev12) or higher, the shutter speed is fixed at Tv7 (1/125 seconds). In this case, appropriate exposure can be obtained by narrowing down the aperture of the taking lens. Note that the shutter speed of Tv7 (1/125 seconds) is the maximum sync speed of the flashlight, and may be a higher sync speed.
[0014]
On the other hand, the shutter speed is decreased as the subject brightness becomes lower than Bv7. Until the shutter speed reaches a limit shutter speed at which camera shake can be prevented, for example, Tv5 (1/30 seconds), the shutter speed is decreased according to the decrease in the subject brightness as in the conventional slow sync photography. In the example shown in FIG. 2, when the subject brightness is reduced to Bv5, the shutter speed becomes Tv5 (1/30 seconds). Therefore, until the subject brightness Bv5, the shutter speed is decreased according to the decrease in subject brightness.
[0015]
When the shutter speed reaches the limit value Tv5 (1/30 seconds) that can prevent camera shake, the shutter speed is not slowed down as the subject brightness decreases, and the shutter speed is fixed at Tv5 (1/30 seconds). To do.
[0016]
After the subject brightness decreases to Bv5 and the shutter speed reaches Tv5 (1/30 seconds), the shutter speed is reduced to Tv5 (1) until the subject brightness decreases from Bv5 to a predetermined exposure value, for example, 2 EV and decreases to Bv3. / 30 seconds). At this time, since the aperture of the photographing lens is fixed to Av5 (F5.6), the background that the flashlight does not reach is exposed under 2 Ev in Bv3.
[0017]
In this embodiment, an example is shown in which the limit shutter speed at which camera shake can be prevented is 1/30 seconds. However, the shutter speed limit value for preventing camera shake is changed in accordance with the focal length of the photographing lens. Also good. For example, the camera shake prevention limit value of the shutter speed is set to 1 / (focal length) second or a value close thereto.
[0018]
Further, the fixed value of the diaphragm is not limited to F5.6, and may be dependent on the open F value of the photographing lens or may be changed according to the luminance. By changing the fixed value of the aperture, the subject brightness at which the shutter speed reaches the limit value 1/30 second for preventing camera shake also changes from Bv5.
[0019]
When the subject brightness is Bv3 or less, the shutter speed is lowered again as the subject brightness decreases. At this time, the shutter speed is set to a high speed at which the exposure is underexposed by 2 Ev, for example, from the appropriate exposure level of the background. That is, the background where the flashlight does not reach is exposed under 2 Ev. In FIG. 2, at a subject brightness Bv3 or less, a shutter speed that is 2 EV faster than the conventional slow sync shooting is set.
[0020]
In this embodiment, when the subject brightness is Bv3 or less, an example in which the shutter speed is high enough to be underexposed by 2 EV than the appropriate exposure of the background is shown. It may be variable or may be arbitrarily variable by the photographer.
[0021]
In such a low brightness, flash photography is often performed against a night scene, and the night scene can be captured more clearly than when the shutter speed is fixed at 1/30 seconds. In addition, since shooting is performed at a high shutter speed, the flow of the night scene image due to camera shake is reduced to a quarter of that in conventional slow sync shooting.
[0022]
Then, at a luminance Bv-2 or less at which the shutter speed is 1 second, the shutter speed is fixed at 1 second, and the shooting is terminated after a maximum of 1 second from the shutter release.
[0023]
FIG. 4 is a flowchart showing processing for determining the shutter speed Tv and the aperture Av based on the subject brightness. The operation of the embodiment will be described with reference to this flowchart. In the following, an example of exposure calculation using apex values will be shown.
[0024]
In step 1, the luminance Bv is detected based on the photometric result of the photometric light receiving element 9. In the subsequent step 2, an exposure value Evc is obtained based on the brightness Bv and the film sensitivity Sv. In Step 3, it is determined whether or not the exposure value Evc is 12 or more. If Evc is 12 or more, the process proceeds to Step 4, and if not, the process proceeds to Step 6.
[0025]
When the exposure value Evc is 12 or more, the shutter speed Tv is set to 7 (1/125 seconds) in step 4, and the aperture Av is set to (Evc−Tv) in step 5 to finish the process.
[0026]
On the other hand, when the exposure value Evc is less than 12, it is determined in step 6 whether Evc is 10 or more. If Evc is 10 or more, the process proceeds to step 7; otherwise, the process proceeds to step 9. In step 7, the aperture Av is set to 5 (F5.6), and in the subsequent step 8, the shutter speed Tv is calculated to be (Evc-Av), and the process ends.
[0027]
If the exposure value Evc is less than 10, it is determined in step 9 whether Evc is 8 or more. If Evc is 8 or more, the process proceeds to step 10, and if not, the process proceeds to step 12. In step 10, the aperture Av is set to 5 (F5.6), and in step 11 the shutter speed Tv is set to 5 (1/30 seconds), and the process is terminated.
[0028]
If the exposure value Evc is less than 8, it is determined in step 12 whether Evc is 3 or more. If Evc is 3 or more, the process proceeds to step 13, and if not, the process proceeds to step 15. In step 13, the aperture Av is set to 5 (F5.6), and in step 14, the shutter speed Tv is calculated to be (Evc−Av + 2), and the process ends.
[0029]
When the exposure value Evc is less than 3, the shutter speed Tv is set to 0 (1 second) in step 15, and the aperture Av is calculated to be (Evc−Tv + 2) in step 16.
[0030]
In step 17, it is determined whether or not the aperture Av is 3 or less. If Av is 3 or less, the process proceeds to step 18, and if not, the process ends. If the aperture Av is 3 or less, the aperture Av is set to 3 in step 18 and the processing is terminated.
[0031]
When shooting is started by operating a shutter release button (not shown), exposure control and flashlight lighting control are performed based on the shutter speed Tv and the aperture Av determined in the above-described processing routine.
[0032]
In the above-described embodiment, an example in which the present invention is applied to a single-lens reflex camera has been described. However, the present invention is not limited to a single-lens reflex camera, and all types of cameras with a built-in or external flashlight. The effects as described above can be obtained.
[0033]
【The invention's effect】
(1) According to the present invention as described above, when flash photographing, if the above first object brightness corresponding to the shutter speed limit subject luminance is prevented shake, the subject brightness determines a shutter speed according to the reduction, the subject brightness is the case between to a second subject luminance to be underexposed by a predetermined exposure value from the first subject luminance, a limit that can prevent blurring of the shutter speed fixed to the shutter speed, the subject brightness is the case of the following second object luminance was set to a slower shutter speed in accordance with the reduction of the subject brightness, when performing flash photography using flash light as the auxiliary illumination light, In indoor shooting, the shutter speed is fixed at a relatively high speed, and flash photography is performed, so that images without image quality degradation due to camera shake can be obtained, while the background is a night view. Even when shooting a person or the like, the background is not crushed into darkness, and a photograph in which the background is clearly reproduced can be obtained.
(2) According to the invention of claim 2, when the subject brightness is equal to or lower than the second subject brightness, the shutter speed is set such that the exposure is underexposed by a predetermined exposure value. A background such as a night view can be imprinted with a constant underexposure.
(3) According to the invention of claim 3, since the predetermined exposure value is variable according to the photographing mode, the background can be imprinted with the optimal underexposure according to the photographing mode.
(4) According to the invention of claim 4, since the predetermined exposure value is arbitrarily variable, the photographer can capture the background of the subject with a desired underexposure.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment.
FIG. 2 is a diagram illustrating shutter speed with respect to subject brightness.
FIG. 3 is a program diagram of shutter speed during flash photography with a flashlight.
FIG. 4 is a flowchart showing a process for determining a shutter speed Tv and an aperture Av based on subject brightness.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shooting lens 2 Aperture 3 Quick return mirror 4 Shutter 5 Film 6 Focus plate 7 Penta prism 8 Photometric lens 9 Photometric light receiving element 10 Flashlight light emitting part 11 Controller 12 Flashlight controller

Claims (6)

A metering unit for measuring subject brightness;
A control unit that calculates an exposure value based on the subject brightness measured by the photometry unit and controls a shutter and a light emitting unit;
Wherein, when flash photographing due to emit the light emitting unit, when the first one or more of the subject luminance to the object luminance corresponding to the shutter speed limit can prevent camera shake, the reduction of the subject brightness depending determines a shutter speed, for until a second subject luminance, wherein the object luminance is underexposed predetermined exposure value from said first object brightness, the shutter speed can be prevented the camera shake fixed to the shutter speed limit, the flash camera capable of photographing when the subject luminance is less than the second brightness value, characterized in that a slow shutter speed with a decrease of the subject brightness. The camera capable of flash photography according to claim 1,
The camera capable of flash photography , wherein the controller sets a high shutter speed at which the exposure is underexposed by the predetermined exposure value when the subject brightness is less than or equal to the second subject brightness . The camera capable of flash photography according to claim 1 or 2,
The camera capable of flash photography , wherein the control unit makes the predetermined exposure value variable according to a photographing mode . The camera capable of flash photography according to claim 1 or 2 ,
The camera capable of flash photography , wherein the control unit arbitrarily varies the predetermined exposure value . The flash-capable camera according to any one of claims 1 to 4 ,
When the subject brightness is equal to or less than a third subject brightness that is underexposed by a predetermined exposure value from the second subject brightness, the control unit is slower than a limit shutter speed capable of preventing camera shake. A camera capable of flash photography, characterized by being fixed to the camera. In the camera capable of flash photography according to any one of claims 1 to 5,
A flash photography camera , wherein the control unit fixes a shutter speed to a maximum sync speed when the subject brightness is equal to or higher than a fourth subject brightness higher than the first subject brightness .

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