JP2596801B2 - Flash photography switching device - 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.

The LS camera is effective for flash photography due to the feature of the shutter opening form, while the FPS camera is capable of exchanging the lens from the light shielding form and controlling the time at a high speed from the operation form.

In order to make use of the features of the above two types of cameras, there has been proposed an interchangeable lens of a type having an LS that operates independently in an interchangeable lens of an FPS camera.

However, since it is a shutter that operates independently as an interchangeable lens, and the control part is individually provided in the FPS and the LS, there are many useless parts.

In order to solve the above problem, the same applicant has already proposed a camera system including LS and FPS. (Japanese Patent Application 63
However, in flash photography, the FPS has a limit speed for synchronizing with the flash, and there is still a problem to be solved as a camera including the FPS and the LS. ing.

(Object of the Invention) The present invention has been made in view of the above problems,
Provide a camera that has an FPS and automatically selects the LS mode when the FPS exceeds the limit speed to synchronize with the flash in the FPS mode for the subject where flash photography is executed The purpose is to:

(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 controlling a shutter speed by a focal plane shutter and setting a focal plane shutter mode for controlling an aperture by the lens shutter; first driving means for controlling a program exposure value and / or an aperture value of the lens shutter; Second driving means for controlling the operation time of the focal plane shutter, sequence control means for controlling the operation timing of the two driving means, and detecting a limit speed for the focal plane shutter to synchronize with flash light. A flash photography switching device comprising: a discrimination means for discriminating; and a forced switching means for setting a lens shutter mode irrespective of the setting of the switching means when the discrimination means determines that the speed exceeds the limit speed for synchronizing with the flash. The above object is achieved.

(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.

The electronic circuit 10 for controlling the step motor 9 includes a first driving unit D1, a sequence control unit SC for controlling the operation timing of the shutter, a photometric circuit including a light receiving element for measuring the subject luminance, and a second Drive means D2 and the like.

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 two electromagnets (not shown) are driven by a second driving unit D2 of the electronic circuit 10. Are operated at desired time intervals to control the exposure time.

The FPS 11 is charged by a known method at the time of film feeding, and when performing a multiple 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 configuration.

The calculating means 105 includes a photometric circuit 101 including a light receiving element for measuring the brightness of the subject, a distance measuring circuit 102 for measuring a distance to the subject, a means 20 for setting a focal length f of the photographing lens 2, and a film sensitivity setting. The signal is output to the switching means 15 and a sequence control means SC described later, using the signal of the means 104 for performing the input as an input.

The switching means 15 selects whether to perform the program exposure operation by the LS or the exposure time control by the FPS. In other words, once you press the part protruding above the camera, LS
Is set to the lens shutter mode in which is operated, and when pressed again, the focal plane shutter mode in which the FPS is operated is set, and when pressed again, the lens returns to the lens shutter mode.

The output Q1 of the calculating means 105 displays the mode corresponding to the mode setting of the switching means 15 and the exposure status in that mode on the display means.

The output Q2 of the arithmetic means 105 outputs a signal corresponding to each mode to the sequence control means SC in order to set an exposure level according to the brightness of the subject.

When the switching means 15 is set to the focal plane shutter mode and the flash device 17 is used, if the operation speed of the FPS exceeds the limit value that can be synchronized with the flash of the flash device by the output Q2. The determination means 16 forcibly sets the lens shutter mode by the forcible switching means 107.

The display means 106 indicates which of the setting modes is set, and when the lens shutter mode is forcibly set, the display means 106 repeatedly displays the setting.

Based on a signal from the switching means 15 or the forcible switching means 107, the sequence control circuit SC switches the first driving means D1 and the second driving means
The operation sequence with D2 is set at a preset timing, FPS11
And activate the LS8.

Next, the operation method will be described with reference to FIGS. 4 to 6, the horizontal axis indicates the elapsed time, and the vertical axis indicates the exposure amount or the screen position on the photographing screen 4.

In the operation flowchart of FIG. 3, step # 1
Indicates a state in which the release button 7 of the camera is depressed and power is supplied to the entire camera device from a power supply (not shown).

In the following, step-by-step description will be given. In step # 2, the information SV from the film sensitivity setting means 104 is
In step 3, the information BV from the photometry circuit 101 is further added to step #
In step 4, information DV from the distance metering circuit 102 is input to the arithmetic circuit 105, and arithmetic is performed in step # 5. In step # 6, the information GV from the flash device 17, the information ZV from the focal length setting means 104, and the above information DV are input to the arithmetic circuit 105 for calculation, and the calculation in step # 7 is performed.

In step # 8, the arithmetic circuit 105
A determination is made as to whether or not the situation is to be used, and if it is set in a state to be photographed in the natural light state, step # 9
Proceed to.

In step # 9, it is determined whether or not to automatically emit light using the flash device 17 as auxiliary light based on the above calculation result.
In step # 10, an automatic exposure operation using natural light is performed.

If it is determined in step # 9 that automatic light emission is required, the process proceeds to step # 11, where it is determined whether the switching unit 15 is set to the LS mode. Therefore, if the LS mode is set, the exposure operation is performed in the sequence shown in FIG. 4 in the order of steps # 18, # 19, # 20 and # 21. The flash device 17 emits light in a known manner according to the signal of the LS.

On the other hand, in step L11, if the FPS mode has been set, the process proceeds to step # 12, where it is determined whether the shutter speed at which the FPS 11 should operate is shorter than the time required for synchronizing the light emission of the flash device with the entire screen. The process proceeds to step # 13, the mode is switched to the lens shutter mode by the forcible switching means 107, and thereafter, the process proceeds to step # 18.

Also, if the time is long in step # 12, step # 14,
The exposure operation shown in FIG. 6 is performed in the order of # 15, # 16, and # 17.

Also, if the LS mode is set in step # 11,
After shifting from step # 13 to step # 18, the LS operation shown in FIG. 4 is performed in the order of steps # 19, # 20, # 21, and # 22.

FIG. 4 is an operation diagram when the switching means 15 is set to the lens shutter mode in which the exposure operation is performed by the LS8. When the release button 7 in FIG. 1 is pressed during photographing, the sequence control means SC first specifies the second driving means D2 to output 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 means SC designates the first drive means D1 to output a signal, opens the LS8, and exposes the film F with the 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 means 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 opens the shooting screen 4.

When the operation of FPS11 ends, the sequence control means 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. 5 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 means 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 means 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 means SC designates the first drive means D1 to output a signal, and closes LS8.

When the operation of the LS8 is completed, the sequence control means 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.

The exposure time by FPS11 is relatively long, so-called F
As shown in FIG. 6, the operation of the PS in the flash synchronization limit speed range is a state in which the front curtain 13 is opened, the flash trigger switch is turned on at the point X, and the screen is completely opened from the position P1 to the position P2. Causes the flash device 17 to emit light.

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

In the above embodiment, when the user sets an operation unit formed outside the camera and selects flash photography, or in the above-described embodiment, the flash unit 17 is attached to the camera, or the flash unit built in the camera is used. Can be switched to a use state, or when the brightness of a subject or a backlight state is automatically detected and an automatic exposure operation is performed by a flash device.

Although the above embodiment has been described using a stepping motor, any motor that can rotate forward and backward can be equivalently configured with, for example, an ultrasonic motor or a DC motor.

Also, a single-lens reflex camera can be configured based on the concept of the present invention.

(Effects) As is clear from the above description, by providing the determination means 16, the FPS mode is set when performing flash photography, and the operation speed of the FPS exceeds the limit speed for tuning to the flash. Automatically switches to the LS mode automatically when it is determined, and the display means displays that fact, and the sequence control circuit SC performs appropriate shooting synchronized with the flash light. The LS and FPS can be activated at the right time to effectively use the features of the two shutters according to the purpose of shooting.

For example, in order to reduce the depth of field during portrait photography, etc., if the focal plane shutter mode is set with the intention of increasing the aperture value, the main subject will be backlit depending on the brightness of the subject. For this reason, when the flash device emits light, the FPS may not be synchronized and may cause so-called exposure unevenness. Even in such a case, in the present invention, the mode is automatically switched to the lens shutter mode suitable for flash photography, and correct photography is performed. However, in this case, the flash device is caused to emit light when the aperture value corresponding to the distance to the main subject is reached, and a program shutter in which exposure to ambient light is performed with the brightness of natural light, or emphasis is placed on the aperture value. Then, a shutter or the like which takes measures such as shortening the exposure time by rotating the motor at a high speed is used.

[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.
The figure shows the flow chart of the camera, and FIGS. 4, 5 and 6 show the operation diagram. DESCRIPTION OF SYMBOLS 1 ... Camera body 2 ... Shooting lens 5 ... Finder 7 ... Release button 8 ... Lens shutter 11 ... Focal plane shutter 15 ... Switching means 16 ... Discrimination means 17 ... Flash device 20 ... Focal length Setting means 104 film sensitivity setting means 105 calculating means 107 forced switching means SC sequence control means D1 first driving means D2 second driving means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroto Tsukiki 934-13, Kadawa, Yotsukaido-shi, Chiba Inside the Seikosha Chiba Works Co., Ltd. Inside Chiba Works (72) Inventor Kanji Ito 934-13, Kadato, Yokkaido, Chiba Prefecture Seikosha Chiba Works (72) Inventor Takayuki Sato 934-13, Kadawa, Yotsukaido City, Chiba Japan Seikosha Chiba Works ( 72) Inventor Takuhito Otora 934-13 Shikato, Yokkaido, Chiba Pref.Sekisha Chiba Works (72) Inventor Teruyo Hayakawa 934-13 Shikato, Yotsukaido, Chiba Pref.Sekiko Chiba Works

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 shut, and a shutter speed is controlled by the focal plane shutter. Switching means for setting a focal plane shutter mode for controlling an aperture by the lens shutter; first driving means for controlling a program exposure value and / or an aperture value of the lens shutter; and controlling an operation time of the focal plane shutter. A second drive unit, a sequence control unit that controls operation timings of the two drive units, a determination unit that detects and determines a limit speed for the focal plane shutter to synchronize with flash light, When another unit is determined to exceed the limit speed tuned to flash, flash photographing switching device and a forced switching means for setting the lens shutter mode regardless of the setting of the switching means.