JPH0553168A - Camera - Google Patents

Abstract

PURPOSE:To switch to a night view photographing mode in which exposure is executed for a long time without having a troublesome switching operation. CONSTITUTION:Any of an accelerating sensor 11, a screw hole switch 20 and a button switch 16 detects whether a camera main body is stably held or not. When a fixing signal is inputted to a CPU 25 from a camera fixing detecting circuit 36, and an object brightness is detected to be equal to or below a specified level by a photometric device 28, the camera is automatically switched to a long time exposure(night view photographing mode) in which stroboscope is used together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera capable of shooting in a night view shooting mode.

[0002]

2. Description of the Related Art Generally, stroboscopic photography is performed when the external light luminance is low. In normal flash photography with a compact camera, the aperture diameter is determined according to the shooting distance to the main subject and the guide number of the flash, and the flash fires when the aperture of the program shutter opens up to that aperture. I'm trying to close. With such stroboscopic photography, proper exposure can be obtained for the main subject, but the background outside the reach of the stroboscopic light is often underexposed, and almost nothing is captured, resulting in a photograph with a poor atmosphere. Tended to be.

In order to solve such an inconvenience, a camera capable of photographing in a night view photographing mode is provided.
At the time of shooting in the night view shooting mode, the timing of closing the program shutter is set to be later than the flash emission time so that the light from the background is sufficiently captured within the extended exposure time. According to this, it becomes possible to photograph the background with a certain degree of brightness, and it is possible to obtain an effect that has not been obtained by the conventional stroboscopic photography.

[0004]

However, in the case of the conventional camera having the night view shooting mode function, the photographer checks the display in the viewfinder or the like to determine whether or not the shooting in the night view shooting mode is suitable. However, there is a problem in terms of operability because the mode switching to the night view shooting mode is a manual operation. Furthermore, especially for beginners, it is difficult to understand the functions of the night view shooting mode itself, and it is difficult to properly select this mode and take good pictures.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to easily use the night view photographing mode, which has been difficult to perform an appropriate selection operation until now without performing a troublesome operation. The purpose is to provide a camera.

[0006]

In order to achieve the above object, the present invention provides first detection means for detecting that a camera is fixed and outputting a camera fixing signal, and external light luminance having a predetermined level. Second detection means for detecting the following and outputting a low-brightness signal, and switching means for switching the shooting mode of the camera to the night-view shooting mode in response to the input of both the camera fixed signal and the low-brightness signal. And are provided.

According to another invention, in a camera with an automatic night view photographing mode, the night view mode can be released, and when it is released, the exposure control of the camera can be performed by strobe light or external light brightness. is there.

Another aspect of the present invention is provided with means for notifying the photographed person that photographing is in progress while the shutter is open in the night view photographing mode.

Further, in another invention, a switch is provided inside the tripod mounting screw of the camera body to detect whether or not the camera is fixed.

[0010]

According to the present invention, when the brightness of the external light is less than a certain level and the camera body is fixed, the mode automatically shifts to the night view mode, and it becomes possible to take an appropriate night view. By notifying the person being photographed that the image is being photographed at the time of photographing, inadvertent movement in the shutter opening can be prevented, and a photograph can be taken without shake by the person being photographed.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 6 shows the appearance of the camera according to this embodiment. In FIG. 6, a photographing lens 3 is provided in a substantially central portion of the front surface of the camera body 2, and a finder 4, a flash discharge tube 5 and a night view mode cancel button 6 for canceling a night view shooting mode are provided on an upper part thereof. A shutter button 8 is provided on the upper surface of the camera body 2. Reference numerals 9 and 10 denote a light emitting unit and a light receiving unit of the distance measuring device. Of the light projected from the light projecting unit 9, the light reflected from the subject is received by the light receiving unit 10 to measure the distance. Has become. An acceleration sensor 11 that detects the fixed state of the camera body 2 is provided inside the camera body 2.
A warning lamp 12 is provided on the left side of the stroboscopic discharge tube 5 and is turned on when shooting is performed in the night view shooting mode to warn the person to be shot that the shooting is in the night view shooting mode.

3 (A) and 3 (B) show the bottom and side surfaces of the camera body 2, respectively. A screw hole 15 for attaching a tripod is provided on the bottom surface of the camera body 2, and a button switch 16 is provided on the side thereof so as to project from the bottom surface. The button switch 16 is turned on when the camera body 2 is placed on a flat surface, and detects that the camera body 2 is maintained in a stable posture.

As shown in the cross-sectional view of the main part of FIG. 2, a screw hole switch 20 including a sliding pin 17 and a pair of contact pieces 18 and 19 having a spring property is provided in the depth of the screw hole 15. Has been. As shown in the drawing, when the tripod screw 23 is screwed into the screw hole 15 to hold the camera body 2 on the tripod 22, the sliding pin 17 resists the bias of the contact piece 18, and the tripod screw 2
It is pushed up by 3 and shorts the contact pieces 18, 19.
This short circuit signal is detected as a signal that the camera body 2 is stably supported by the tripod 22. When the tripod 22 is removed from the camera body 2, the contact piece 18 separates from the contact piece 19 due to its own elasticity.

FIG. 1 is a block diagram showing the structure of a camera according to an embodiment of the present invention. Here, the AF device 24 controls the light projecting unit 9 and the light receiving unit 10 described above by a signal from the CPU 25 to measure the subject distance, and supplies a distance measurement signal corresponding to the subject distance to the CPU 25. The CUP 25 calculates the amount of extension of the lens based on this distance measurement signal, drives the lens driving device 27, and moves the taking lens 3 to a position in focus. The photometric device 28 measures subject brightness and inputs the obtained photometric data to the CPU 25. The exposure control device 30 is based on the photometric data supplied from the CUP 25, and according to a predetermined exposure program, the shutter speed and aperture value (aperture diameter of the program shutter).
And the program shutter 3 to satisfy this.
Control the operation of 1. When the CPU 25 determines that the photometric data is lower than the predetermined level, the CPU 25 controls the operation of the strobe light emitting circuit 33 so that the stroboscopic photography is automatically performed.

As the strobe light emission circuit 33, a constant charge type is used, and the main capacitor for strobe light emission is charged when the power switch of the camera is turned on. The timing of light emission of the strobe discharge tube 5 is determined by flashmatic control. Therefore, the CPU 25 supplies a trigger signal for strobe light emission to the strobe light emission circuit 33 in accordance with the distance measurement signal measured by the AF device 24. When the photometric data is lower than the predetermined level and the main capacitor is not charged to the specified voltage, the LED driver 34 is driven and a warning is displayed by the LED (not shown) provided in the finder 4. Done. The LED in the viewfinder 4 is also turned on when the button 6 for canceling the night view shooting mode is operated, and a warning is displayed to the photographer to that effect. Further, the lamp driver 35 is driven during shooting in the night view shooting mode, and drives the warning lamp 12 to blink.

The camera fixing detection circuit 36 receives signals from the acceleration sensor 11, the screw hole switch 20, and the button switch 16 described above, and detects whether or not the camera body 2 is stably supported so as not to shake. When the camera is supported stably, the camera fixed signal is input to the CPU 25. Since it is possible to detect whether or not the camera body 2 is stably supported only by using the acceleration sensor 11, the screw hole switch 20 and the button switch 16 can be omitted, and conversely, the acceleration sensor 11 can be omitted. Omitted and screw hole switch 20 or button switch 1
Only 6 may be used. When only the acceleration sensor 11 is used, the camera body 2 may be fixed by any method, and there is an advantage that it is easy to have a waterproof structure. Further, when the screw hole switch 20 and the button switch 16 are used, The cost of the camera can be reduced. The release signal generator 38 detects the pressing operation of the shutter button 8 and sends the operation signal to the CPU 25.
Upon receiving this operation signal, the CPU 25 executes the above-described autofocus processing, exposure control processing, and processing for shifting to the automatic night view mode.

The operation of the camera thus constructed is shown in FIG.
A description will be given according to the flowchart in FIG. When the operator presses the shutter button 8 halfway, the release signal generator 38 causes C
A half-press signal is supplied to the PU 25, and the CPU 25 operates the AF device 24 to measure the distance. Then, the photographing lens 3 is positioned based on the distance measurement signal obtained thereby. Further, the photometric device 28 measures the subject brightness and inputs the photometric data to the CPU 25. Here, the photometric data is a value above a predetermined level, that is, without using a strobe,
When the subject brightness is such that the shutter speed is faster than 1/30 seconds (about the reciprocal of the focal length of the taking lens 12) in which camera shake is a concern, shooting in the normal mode is performed. In this case, the exposure program is simply referred to, and the program shutter 31 corresponding to the photometric data.
The aperture diameter and shutter speed are uniquely determined.

When the photometric data is smaller than the predetermined value, it is determined whether or not a fixed signal is input from the camera fixed detection circuit 36 and whether or not the night view mode release button 6 is operated. When the fixed signal is not input to the CPU 25, or when the night view mode release button 6 is operated even when the fixed signal is input, the flash photography mode is automatically switched. When the mode shifts to the strobe photographing mode, the charging voltage of the main capacitor is confirmed, and if the main capacitor is not charged, a warning is displayed in the viewfinder and at the same time, the shutter lock mechanism is activated and the second step pressing of the shutter button 8 is prohibited.

When shooting is performed in a proper strobe shooting mode, as shown in FIG. 5, the aperture diameter of the program shutter 31 is set according to the distance measurement data obtained from the AF device 24 and the object distance and strobe light. The strobe discharge tube 5 emits light at the time when the opening diameter (F ₁ ) calculated from the guide number and the guide number is reached. Since the opening diameter of the program shutter 31 is proportional to the shutter time, it is possible to know the timing when the program shutter 31 reaches the opening diameter F ₁ by monitoring the shutter time. After that, the program shutter 31 is closed and the exposure ends at the time point T ₁ . Also,
The program shutter 31 can be continuously opened after the strobe discharge tube 5 emits light in order to improve the depiction of the background or to enable daytime synchro photography. In this case, camera shake occurs at the shutter speed. Not to T
_The exposure is set to end in ₂ (1/30 second). When the strobe off button 39 for prohibiting the stroboscopic light emission is operated, stroboscopic photography is prohibited even under a low brightness condition, and a camera shake warning is displayed in the viewfinder 4.

When a fixed signal is input from the camera fixing detection circuit 36 and the night scene mode release button 6 is not operated, the night scene photographing mode is automatically entered. In the night view shooting mode, the light emission timing of the strobe discharge tube 5 is determined in correspondence with the distance measurement data as in the strobe shooting mode, but the opening and closing of the program shutter 31 is controlled as shown by the dashed line in FIG. , The shutter speed is T
₃ , that is, the shutter time T _{2 of the} camera shake limit is extended. The value of the shutter time T ₃ is underexposure about 1 EV or more than the shutter opening time (long exposure) which is the proper exposure calculated by the photometric data at that time and the F number of the taking lens 3. Is set as follows. This is because it is necessary to photograph the night view like a night view, to provide the main subject with an effect of making the background dark, and to prevent the main subject from being overexposed. A limit function for limiting the maximum exposure time may be added in order to prevent an extremely long exposure time due to low background brightness.

Therefore, according to the above-described exposure control, the main subject is exposed to the same extent as in stroboscopic photography by flashmatic, and the shutter that extends beyond the hand-shake limit is set for the background where strobe light does not reach. By the time T ₃ per second, it becomes possible to increase the exposure amount and improve the descriptiveness as compared with the stroboscopic photography described above. Of course, even if such a long-time exposure is performed, the camera body 2 is fixed, so there is no risk of camera shake. Further, when shooting in the night view shooting mode, the warning lamp 12 is turned on to notify the subject that a long exposure will be performed, and thus the subject is cautioned not to move much. Can be made

The above night view photographing mode is a case where a strobe is also used. However, if the photographing is performed while the strobe off button 39 is operated or the main capacitor is not charged, the strobe is also used. Exposure control is performed in the night view shooting mode. In this case,
The exposure program is determined by the photometric data obtained from the photometric device 28. For example, as shown by the chain double-dashed line in FIG. 5, after the program shutter 31 reaches the maximum aperture diameter F ₂ , exposure is performed until the shutter time T ₄ is reached. Is continued and the exposure is controlled so that the proper exposure is achieved without the strobe light emission.
During this exposure, the warning lamp 12 is turned on to indicate to the person being photographed that long-time exposure is being performed.

The present invention has been described above with reference to the illustrated embodiment, but the present invention is not limited to a camera using a program shutter, but an exposure control for individually controlling a shutter speed and an aperture diameter according to a subject brightness. It can also be applied to a system camera and a camera with a built-in automatic light control strobe as a strobe.

[0024]

As described above, according to the present invention, when the subject brightness is below a predetermined level and the camera is stably held so as not to shake, the mode automatically shifts to the night view photographing mode. Therefore, even inexperienced users can easily perform special shooting with a rich atmosphere of night view shooting mode. In addition, by allowing the automatically selected night view shooting mode to be intentionally released, a familiar user can select various shooting modes depending on the case, and the degree of freedom in exposure control is increased. It becomes possible to have it.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a camera using the present invention.

FIG. 2 is a sectional view of an essential part of a camera using the present invention.

FIG. 3 is a bottom view and a side view of a camera using the present invention.

FIG. 4 is a flowchart showing a processing procedure of a camera using the present invention.

FIG. 5 is a graph showing an opening characteristic of a program shutter.

FIG. 6 is a perspective view of a camera using the present invention.

[Explanation of symbols]

 2 Camera body 6 Night view mode release button 11 Accelerometer 12 Warning lamp 16 Button switch 20 Screw hole switch 24 AF device 25 CPU

Claims (4)

[Claims] 1. A camera having a night view photographing mode for photographing with a long exposure exceeding a camera shake limit, a first detecting means for detecting that the camera is fixed and outputting a camera fixing signal, and a subject. Second detection means for detecting that the brightness is lower than a predetermined level and outputting a low brightness signal, and setting the shooting mode of the camera to the night view shooting mode in response to inputs of both the camera fixed signal and the low brightness signal. A camera provided with a switching means. 2. A means for canceling the night view shooting mode set by the switching means is provided, and shooting is performed in the normal strobe shooting mode or in the normal shooting mode based on the external light brightness by releasing the means. The camera according to item 1. 3. The camera according to claim 1, further comprising display means for notifying the person being photographed that the shutter is open during photographing in the night view photographing mode. 4. The switch according to claim 1, wherein the first detecting means is provided inside a screw hole for attaching a tripod and detects whether or not the tripod is attached.
The listed camera.