JPS62184442A - Work control device for ae finder - Google Patents

Abstract

PURPOSE:To prevent the consumption of unnecessary electric power and the misdisplay of photometric information by automatically interrupting current supply to an AE finder when a photographing lens including a mechanical shutter is loaded to a lens mounting part. CONSTITUTION:When the lens 33 including the mechanical shutter device 35 in stead of a systemized lens unit 20, a contact point 3a in a contact point part 23 is not dropped to the potential of earth and a transistor (TR) 25 is interrupted. As the result, current supply to an AE finder control circuit 48 is interrupted, and even if an AE finder is loaded, the circuit 38 is disabled. Thereby,photometric information also is not outputted from the circuit 48 and an LED driving circuit 57 is also disabled, so that an operator can be prevented from misrecognition of display of meaningless exposure information. Consequently, the consumption of unnecessary electric power and the misdisplay of photometric information can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an A
This invention relates to an operation control device for an E-finder.

[Conventional technology]

As is well known, a -eye reflex camera is provided with a movable reflex mirror (hereinafter referred to as a reflex mirror).

This reflex mirror is adapted to be moved between a finder observation position where the photographing light beam is reflected toward the focus plate and a photographing position where it is evacuated from within the photographing optical path. Further, in order to perform automatic exposure control in such an eye reflex camera, a light receiving element for photometering the subject brightness is provided in the finder optical path after the focus plate, for example, in the vicinity of the eyepiece. When using an AE finder with a built-in light-receiving element, when the reflex mirror is at the finder observation position, the light-receiving element measures the light from the subject screen that is imaged on the reticle, and the light is thus obtained. The measured photometric information will be used for exposure control.

By the way, some large formant single-lens reflex cameras that use 120 film, for example, utilize a lens shutter as a shutter. The lens shutter is built into the photographic lens, but if the photographic lens is systematized with electrical connection to the camera body in mind, the lens shutter can be automatically activated according to photometry information from the AE finder. You will be able to control exposure.

By the way, in the large format cameras mentioned above, the photographic lenses are also expensive, so in addition to the systemized photographic lens, it would be possible to use other conventionally used large format photographic lenses. Photography modes can be greatly expanded without incurring any expense. From this point of view, it is desirable to be able to attach even a conventional photographic lens to a camera body via an adapter.

[Problem that the invention seeks to solve]

However, unlike the systemized photographic lens, the conventional photographic lens that is attached via an adapter as described above cannot be electrically connected to the camera body. In particular, most conventional photographic lenses use a mechanical interlocking mechanism, such as a shutter charge mechanism or a shutter speed adjustment section.

Since it has a built-in so-called mechanical shutter device consisting of a shirt release section and the like, automatic exposure control cannot be performed even when used in conjunction with the above-mentioned AE finder. Therefore, even when a conventional photographic lens is used, supplying power to the AE finder results in unnecessary power consumption.

Furthermore, for example, when displaying exposure information in the viewfinder according to photometric information from the light receiving element,
This results in a completely meaningless display.

The present invention has been made in view of the drawbacks of the prior art, and it is an object of the present invention to provide an AE finder operation control device that eliminates wasteful power consumption due to the AE finder.

[Means for solving problems]

To achieve the above object, the present invention cuts off the power supply to the AE finder when a photographic lens with a built-in mechanical shutter and whose shutter cannot be controlled based on photometric information from the AE finder is used. ing. As a result, when a photographic lens with a built-in mechanical shutter is attached to the lens mounting section of a camera, power consumption to operate the light-receiving element built into the AE finder is eliminated, and the power from the light-receiving element inside the AE finder is removed. If the device is equipped with a processing circuit that performs arithmetic processing on photometric information, power consumption by this processing circuit can also be avoided.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 2 showing the external appearance of a camera using the present invention, a mounting surface 3 for mounting a film magazine 2 is formed on the back surface of a camera body 1. On this mount surface 3, so as to surround the exposure aperture 3a,
A metal fitting 4 is provided for mounting the film magazine 2 in a bayonet manner, and a contact portion 5 is provided for electrically connecting the camera body 1 and the film magazine 2. When the film magazine 2 is attached to the camera body 1, the contact portion 5 on the camera body 1 side is connected to the contact portion 6 of the two examples of film magazines, as shown in FIG.

When the contact portion 5.6 is connected in this manner, power is supplied from the bath battery socket 9 provided in the camera body 1 to the film magazine control circuit 10 built in the film magazine 2 by turning on the power switch 8. In addition, the film magazine control circuit 10
The operation of the camera body 1 is controlled by instructions from a CPU 12 built into the camera body 1. The film magazine control circuit 10 drives, for example, a film winding motor 13 and feeds back a film winding completion signal to the CPU 12. In addition, code 1
Reference numeral 4 indicates a light-shielding lid, which will be pulled out after the film magazine 2 is installed.

A pair of guide tubes 15 protruding from the front surface of the camera body 1 guide the movement of the extension base 17 supporting the lens board 16 in the optical axis direction. A lock claw 18 is provided on the lens board 16, and this lock claw 1
8, the lens unit 20 in which the photographing lens 19 is incorporated is fixed to the lens board 16 in a light-tight manner. This systemized lens unit 20 includes a contact portion 22 on its mounting surface. When this lens unit 20 is mounted on the lens board 16, the contact portion 22 is connected to a contact portion 23 provided on the mounting surface of the lens board 16.

As shown in FIG. 1, the contact portion 22 on the lens unit 1-20 side is provided with a contact 22a connected to a ground common to the camera body 1 side. This contact 22a
is connected to the contact 23a on the lens board 16 side, and when this becomes ground potential, the switching transistor 2
5 is conductive.

Therefore, like the film magazine control circuit 10, the lens unit control circuit 24 built into the lens unit 20 receives power from the hatchery bag 9, and its operation is controlled by instructions from the CPU 12.

This lens unit control circuit 24 controls the shutter 28 via a shutter drive circuit 27. That is, as will be described later, the shutter drive circuit 27
The shutter 28 is operated at the optimum shutter speed obtained as a result of calculation by the UI 2 or at the shutter speed manually set using the shank dial 54, which will be described later.

Note that the reference numeral 29 indicates a signal code that electrically connects the lens board 16 and the camera body 1, and the reference numeral 3
0 indicates a bellows that optically connects the back surface of the lens board 10 and the front surface of the camera body 1.

A conventional photographic lens 33 can also be mounted on the lens board 16 in a light-tight manner via an adapter 32. The adapter 32 is connected to the lens unit 20.
Since it has a mount surface having the same shape as the mount surface of , it can be mounted on the lens board 16 in exactly the same way as the lens unit 20 using the lock claw 18 .

However, in the conventional photographic lens 33 with a built-in mechanical shutter device 35, there is no need to make an electrical connection to the camera body, so no contact portion is provided on the mounting surface of the adapter 32. And this mechanical shutter device 35
The shutter is charged manually by a charge lever 36, and opened and closed by a cable release 37. Of course, the shutter speed can be appropriately set using a well-known shutter (not shown).

A focus plate 38 is installed on the top surface of the camera body 1. During viewfinder observation, the light beam from the photographing lens 19 built into the lens unit 20 is reflected by a reflex mirror 40 rotatably provided within the camera body 1 and formed into an image on the focus plate 38. Although the shutter 28 is open at this time, a shielding plate 41 is placed behind the reflex mirror 40, so that the light beam does not leak to the film magazine 2 side.

When performing automatic exposure control using the lens unit 20, an AE finder 45 is attached to cover the upper surface of the focus plate 38. When the AE finder 45 is attached, the contact portions 46 and 47 are connected. The AE finder control circuit 48 built into the AE finder 45 receives power from the battery pack 9 via the transistor 25, and also receives power from the CPU.
Its operation is controlled by commands from 12. Note that the reference numeral 50 in FIG. 1 indicates a light receiving element connected to the AE finder control circuit 48, and measures the brightness of the subject screen imaged on the focus plate 38. The brightness information obtained from the light receiving element 50 is input to the CPU 2 after being subjected to electrical processing such as A/D conversion by the AE finder control circuit 48 .

The camera body 1 is provided with a photographing mode setting dial 53 which also serves as a power switch 8, and a shutter dial 54 for setting the shutter speed.

By operating the mode setting dial 53, it is possible to select whether to perform frame-by-frame normal photography, continuous photography, or multiple photography. The shutter dial 54 is set to the "AE" index when the exposure control mode is set to the AE mode, and is set to an appropriate shutter speed index when the exposure control mode is set to the manual mode. In the manual mode, the shutter 28- is operated via the shutter drive circuit 27 in accordance with the set shutter speed.

On the other hand, in the rAEJ mode, the subject brightness information measured by the light receiving element 50, the aperture value information input from the lens unit 20 side, and the film magazine 2
CPU 1 depending on film sensitivity information etc. input from the side.
2 performs calculation, and the shutter drive circuit 27 is operated based on the appropriate shutter speed obtained as a result of this calculation.

When the systemized lens unit 20 is attached and the mode setting dial 53 is set to the normal shooting mode for the index rSJ and the shutter dial 54 is set to the "AE" mode, the operation is as follows. First, the power switch 8 is turned on using the mode setting dial 53, and the CPU 1
2 becomes ready for operation, and the film magazine control circuit 10. Power is supplied to each of the lens unit control circuits 24. Then, the CPU 12 controls the operation of each control circuit according to the sequence program stored in the ROM 55.

When the systemized lens unit 20 is attached, the contact 23a connected to the base terminal of the transistor 25 becomes the ground potential by being connected to the contact 22a, so the transistor 25 becomes conductive and A
Power is also supplied to the E-finder control circuit 48. As a result, the AE finder control circuit 48 is activated, and the light receiving element 50 measures the light from the subject screen imaged on the focus plate 3°8, and the photometry information is sent to the CPU 12 via the AE finder control circuit 48. is input.

The CPU 12 performs calculations based on this input information and other exposure determining information such as film sensitivity information and aperture value information, and the calculation results are displayed on the LE 058 via the LED drive circuit 57. The display of exposure information by the LED 58 is then observed within the finder via the AE finder 45.

After checking the display on LED 58, press release button 6.
0 (FIG. 2), the CPU 2 first outputs a drive signal to the shutter drive circuit 27 via the lens unit control circuit 24, and thereby the shutter 28
will be closed. After that, the mirror drive circuit 62 is activated and the reflex mirror 40 is raised. Note that the shielding plate 41 also rises following the rise of the reflex mirror 40 via a well-known interlocking mechanism.

When the reflex mirror 40 and the shielding plate 41 reach the completely raised position, the CPU 12 outputs a shutter speed signal corresponding to the subject brightness obtained by the light receiving element 50 to the lens unit control circuit 24.

As a result, the shutter drive circuit 27 opens and closes the shutter 28 at an appropriate time in response to the shutter time signal to perform exposure. Note that the aperture value is set in advance on the lens unit 20 side.

When the exposure is thus completed, the CPU 2 returns the reflex mirror 40 and the light shielding plate 41 to their initial positions via the mirror drive circuit 62. Thereafter, the CPU 12 outputs an activation signal to the film magazine control circuit 10.

As a result, one frame of film is wound up, and one shooting sequence is completed. Note that when the mode setting dial 53 is set to the continuous shooting mode with index "C", the reflex mirror 40 and the shielding plate 41 are moved up while the release button 60 is pressed.

Opening and closing of shutter 28, reflex mirror 40 and shielding plate 41
The down operation, the film winding operation, and the shutter charging operation are repeated.

Further, in the multiplex shooting mode, even if one exposure is completed by operating the shutter 28, the film magazine control circuit 10 is not operated and winding of the film is omitted.
In the same film frame? It becomes possible to give Jt several exposures.

By the way, instead of the systemized lens unit 20, a mechanical shutter device 35 is connected via an adapter 32.
When the photographing lens 33 containing a built-in lens is mounted on the lens board 16, the contact 23a in the contact portion 23 is no longer lowered to the ground potential, and the transistor 25 is turned off.

As a result, the power supply to the AE finder control circuit 48 is cut off, and the AE finder control circuit 48 becomes inactive even if the AE finder 45 is attached.

In this way, when the photographing lens 33 which has a built-in mechanical shutter device 35 and does not require electrical connection with the camera body 1 is used, if the power supply to the AE finder 45 is cut off, it is originally in an unusable state. The AE finder control circuit 48 consumes no power at all, which is effective in preventing unnecessary power consumption. Also, A.E.
Since photometric information is no longer output from the finder control circuit 48, the LED drive circuit 57 is also not activated.
This eliminates power consumption, and at the same time eliminates the risk of misunderstanding meaningless exposure information displayed. Of course, the same function can be obtained even when no photographic lens is attached to the lens board 16.

Note that a photographic lens 33 with a built-in mechanical shutter device 35
When using the mirror-up lever 65 (Figure 2), open the shutter blades using the manual operation, adjust the framing and focus, close the shutter blades, and then use the mirror up lever 65 (Figure 2).
After the reflex mirror 40 and the light shielding plate 41 are raised by the above operation, the cable release 37 is used to open and close the shutter blade. Furthermore, in carrying out the present invention, an adapter used when using a photographic lens with a built-in mechanical shutter is provided with, for example, a signal pin, and when the adapter is attached, the signal pin is used to connect the AE finder. Alternatively, a switch provided on the power supply path may be turned off. Furthermore, the present invention can be similarly applied to a camera in which the AE finder 45 is integrated with the camera body 1.

〔Effect of the invention〕

As explained above, according to the AE finder operation control device of the present invention, when a photographic lens with a built-in mechanical shutter is used and there is no longer a need to use the light receiving element built into the AE finder, the AE finder automatically This is to cut off the power supply to the AE finder. therefore,
This will help prevent unnecessary power consumption. Furthermore, in the case where photometric information from the AE finder is displayed, the display section is also not activated, which prevents power consumption and eliminates erroneous display.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is an external view of a camera using the present invention. 1...Camera body 9...Battery back 16...Lens board 20...Lens unit 32...Adapter 33...Photographing lens (with built-in mechanical shutter device) 45...
AE finder 50... Light receiving element.

Claims (3)

[Claims] (1) An AE finder with a built-in light receiving element for photometering the finder light after the focus plate is provided, and
In a camera provided with a lens mounting part to which either a photographic lens with a built-in electronic shutter whose operation is controlled by an electric signal from a camera body or a photographic lens with a built-in mechanical shutter can be mounted, An operation control device for an AE finder, characterized in that when a photographic lens having a built-in mechanical shutter is attached, power supply to the AE finder is cut off. (2) A as set forth in claim 1, wherein the photographing lens incorporating the mechanical shutter is attached to the lens attachment part via an adapter.
E-finder operation control device. (3) The AE finder operation control device according to claim 1, wherein the AE finder is detachably attached to a camera body.