JP2667991B2 - camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a camera having a lens shutter and a focal plane shutter.

(Prior art and its problems) Cameras equipped with a lens shutter (hereinafter referred to as LS) (hereinafter referred to as LS camera) and cameras equipped with a focal plane shutter (hereinafter referred to as FPS) (hereinafter referred to as FPS)
Cameras) are all well known.

In the above-described camera, a known technique is used for detecting a certain voltage level when a power supply voltage is reduced, and issuing a warning when the power supply voltage is reduced to a predetermined value or less to notify that the battery is depleted. .

However, there is no problem if the battery can be replaced immediately, but in general, the user often does not carry the battery, and thus often continues shooting.

On the other hand, the same applicant has proposed a camera equipped with an LS and an FPS. (Japanese Patent Application No. 63-166398 (JP-A-2-15247)) At this time, a camera equipped with both an LS and an FPS In this case, since both are driven by one operation, there is a problem that the battery is consumed more quickly than a camera having only one of them.

(Object of the Invention) The present invention has been made in view of the above problems,
It is an object of the present invention to provide a camera equipped with an FPS, which makes full use of its features and can extend the remaining battery life even when the power supply voltage drops.

(Means for Achieving the Object) According to the present invention, in a camera including a lens shutter for performing a program exposure operation and an aperture adjustment operation and a focal plane shutter, a lens shutter mode in which the lens shutter operates as a program shutter, Switching means for setting a focal plane shutter mode in which a shutter speed is controlled by a focal plane shutter and an aperture is controlled by the lens shutter; a battery for driving a camera; and a battery voltage detecting means for detecting a voltage of the battery. The above object is achieved by a camera comprising: a forced switching unit for setting the shutter mode to a specific mode when the battery voltage detecting unit detects a drop in voltage; and a sequence control unit for controlling the operation timing of the shutter. You.

(Configuration) Referring to the drawings showing an embodiment of the present invention, in detail, in FIG. 1, a photographing lens 2 is mounted on a camera body 1 while being supported by a lens barrel 3. The subject image passing through the lens 2 forms an image on a photosensitive material F (hereinafter, referred to as a film) stored behind a range limited by the photographing screen 4.

A finder 5 having a field frame at the top of the camera body;
There is provided a light-shielding tube 6 for blocking harmful light from a portion other than the taking lens to the film, and a release button 7 for operating the camera is provided on the upper surface of the camera.

A lens shutter (LS) 8 for opening and closing the lens opening is provided behind the taking lens 2, and the lens opening is normally closed by shutter blades 8a.

The stepping motor 9 is a shutter blade that is disposed in the lens barrel 3 and also serves as an aperture according to an output signal of the first driving unit D1.
8a opens and closes.

An electronic circuit 10 for controlling the step motor 9 includes a first driving unit D1, a sequence control circuit SC for controlling the operation timing of each shutter, a photometric circuit including a light receiving element for measuring the subject luminance, and a second It is composed of driving means, but all of them are publicly known and will not be described in detail.

The focal plane shutter (FPS) 11 has a structure in which a front curtain 13 and a rear curtain 14 are supported on a substrate 12 attached to the camera body 1, and is driven by a second driving unit D 2 of a known electronic circuit 10.
When two electromagnets (not shown) are sequentially operated, they are operated at desired time intervals to control the exposure time.

Note that the FPS 11 is charged by a known method at the time of film feeding, and when performing a large-volume exposure operation, the FPS 11 is separated from the film feeding and charged alone.

Switching means 15 is provided at the top of the camera to select whether to perform photographing using FPS11 or LS8.

FIG. 2 is a block diagram showing an operation system having the above-described configuration. The switching means 15 is set so that either the FPS 11 or the LS 8 operates. On the basis of the signal from the switching means 15, the sequence control circuit SC switches the first driving means D1 and the second driving means
FPS11 and LS8 are activated at a preset timing of the operation sequence with D2. SE is the switching means 15 when the battery voltage detecting means BC detects the voltage drop by the forced switching means.
Regardless of the signal of, the FPS11 is kept open and the LS8 is set to the BC mode in which the exposure operation is performed.

That is, when the battery voltage is high, the battery voltage detecting means BC
Output B becomes “H” level, and as is clear from the figure,
The output FP / ▲ ▼ of the forced switching means SE becomes “L” when LS8 is selected as selected by the switching means 15 and becomes “H” when FPS11 is selected, and the output state is irrelevant. .
Since the output B becomes "L" when the battery voltage is low, the signal FP / ▲ in this case is independent of the setting of the switching means 15.
Since ▼ becomes “L”, the operation mode is the LS8 operation mode.

Next, the operation method will be described with reference to FIG. 3 and FIG. In the figure, the horizontal axis indicates the elapsed time, and the vertical axis indicates the exposure amount or the screen position on the photographing screen 4.

FIG. 3 is an operation diagram when the switching means 15 is set to a lens shutter mode in which an exposure operation is performed by the LS8. When the release button 7 in FIG. 1 is pressed during photographing, the sequence control circuit SC first specifies the second driving means D2 and outputs a signal, and the front curtain 13 of the FPS 11 is moved to one end P of the screen.
The photographing screen 4 is opened by operating from 1 to the other end P2.

Next, the sequence control circuit SC designates the first driving means D1 to output a signal, opens and closes the LS8, and exposes the film F with a light amount corresponding to the area Q1. At this time, the LS 8 performs a program exposure operation combining the aperture and time depending on the brightness of the subject.

Subsequently, the sequence control circuit SC designates the second driving means D2 to output a signal, activates the rear curtain 14 of the FPS 11 from one end P1 to the other end P2, and closes the photographing screen 4.

When the operation of FPS11 ends, the sequence control circuit SC
A signal for winding the film F up to the new frame number is output, and a motor (not shown) is operated to charge the FPS 11.

With the above operation, the photographing in the lens shutter mode is completed.

FIG. 4 is an operation diagram when the switching means 15 is set to a focal plane shutter mode in which the FPS 11 performs an exposure operation.

When the release button 7 in FIG. 1 is pressed during photographing, the sequence control circuit SC first specifies the first driving means D1 to output a signal, and opens the LS8 to a predetermined aperture value d1, Open the lens opening.

Next, the sequence control circuit SC designates the second driving means D2 to output a signal, and sequentially operates the front curtain 13 and the rear curtain 14 of the FPS 11 to expose the film F. At this time, the front curtain 13 and the rear curtain 14 have an aperture value d of LS8 depending on the brightness of the subject.
It operates at a time interval t that gives an appropriate exposure amount in combination with 1.

Subsequently, the sequence control circuit SC designates the first driving means D1 to output a signal, and closes LS8.

When the operation of the LS8 is completed, the sequence control circuit SC outputs a signal for winding the film F to a new number of frames, and operates a motor (not shown) to charge the FPS11.

With the above operation, the photographing in the focal plane shutter mode is completed.

FIG. 5 is an operation diagram when the sequence control circuit SC automatically sets the BC mode when the battery voltage drops in the state where the focal plane shutter mode is set.

That is, it shows the operation diagram of the LS and the FPS and the current consumption at that time. The horizontal axis indicates the elapsed time, and the vertical axis indicates the exposure amount on the photographing screen, or the screen position and the current.

FIG. 5 (a) shows the current consumption i corresponding to the operation diagram in the focal plane shutter mode of FIG. 4, and FIG. 5 (b) shows the state when the BC mode is set from the above state. The operation diagram and the current consumption at that time are shown correspondingly. The drawing shows that the first image L1 and the second image L2 are continuously photographed.

That is, when the power switch S1 is turned on by the release operation of the camera, after the FPS11 is opened, the LS8 performs the exposure operation, and the shooting is completed.

When taking a picture after the next time, since the FPS 11 is open, the exposure operation can be performed only by the opening / closing operation of the LS8.

Further, the current flowing through the driving means D1 and D2 in the above sequence is consumed at the time of the FP opening and closing operation and the LS opening and closing operation, and is consumed only at the time of the LS opening and closing after the next photographing.

FIG. 6 (b) shows an embodiment in which, when the battery voltage drops in a state where the lens shutter mode is set, the mode is automatically switched to the BC mode, the LS8 is opened, and the exposure operation is performed by the FPS11. In this case, a similar effect can be obtained.

That is, as in the case of FIG. 5, FIG.
The operation diagram and current consumption of LS and FPS in the case of normal operation of the lens shutter mode are shown.
It is the same as FIG.

FIG. 6B shows that the first mode F1 and the second mode F2 are continuously photographed by the FPS after switching to the BC mode.

FIG. 7 is a block diagram showing an operation system in this case. The output B of the voltage detecting means BC operates in the same manner as in FIG. 2, and the forced switching means SE operates in the same manner.

At this time, the LS8 may not be fully opened but may have a commonly used aperture diameter.

As described above, when the battery voltage decreases, the switching means 15
Is automatically set to BC mode regardless of FPS mode or LS mode.

(Effect) As is clear from the above description, in a camera equipped with an LS and an FPS, by disabling one of the shutters when the power supply voltage is reduced, the remaining battery life can be extended correspondingly. Therefore, there is an effect that more pictures can be taken until the battery is replaced.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a sectional view of a camera, FIG. 2 is a block diagram showing an operation system of the camera, and FIG.
FIGS. 4, 4 and 5 are operating diagrams, FIG. 7 is a block diagram of another embodiment corresponding to FIG. 2, and FIG. 6 is an operating diagram of FIG. 1 camera body 2 photographing lens 5 viewfinder 7 release button 8 lens shutter 11 focal plane shutter 15 switching means SE forced switching means BC voltage detecting means SC Sequence control means D1 First drive means D2 Second drive means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Hirai 934-13 Shikado, Yotsukaido, Chiba Prefecture Seikosha Chiba Works Co., Ltd. Chiba Works (72) Inventor Kenichi Watanabe 934-13 Shikato, Yotsukaido, Chiba Prefecture Seikosha Chiba Works Co., Ltd. 72) Inventor Yusuke Konishi, 934-13 Shikato, Yotsukaido, Chiba, Ltd. Inside the Chiba Works, Seikosha Co., Ltd. (56) References JP-A-55-40464 (JP, A) JP-A-52-98520 (JP, A) Special JP-A-52-148118 (JP, A) JP-A-47-37930 (JP, A) JP-A-55-164618 (JP, U)

Claims (1)

(57) [Claims] 1. A camera provided with a lens shutter for performing a program exposure operation and an aperture adjustment operation and a focal plane shutter, wherein a lens shutter mode in which the lens shutter operates as a program shutter, and a shutter speed is controlled by the focal plane shutter. A switching means for setting a focal plane shutter mode for controlling an aperture by the lens shutter; a battery for driving a camera; a battery voltage detecting means for detecting a voltage of the battery; A camera comprising: forcible switching means for setting the shutter mode to a specific mode when a drop is detected; and sequence control means for controlling an operation timing of a shutter.