JPS63172254A - Camera system - Google Patents

Abstract

PURPOSE:To prevent a film from being uselessly used due to the miss of a fault in a stop by advancing a photographing sequence only when a a voltage on the lens side is more than a prescribed value and a diaphragm to be stopped is decided as a stopped state. CONSTITUTION:In a camera system for supplying power from a camera to a lens through contacts 23a, 23b between them and driving the stop of the lens by a motor 24, the power supply voltage is checked by a voltage detecting circuit 36 during the stopping drive of the lens, and when the voltage is mare than the prescribed value and the normal drive of the diaphragm is decided by a diaphragm opening switch 33, the photographing sequence can be advanced. Even when the power supply voltage is dropped and a photographer can not set up a required stop value, or when the stop is completely disabled, the generation of the accident is informed to the photographer, so that the photographer can be concentrated into photographing operation safely without uselessly using the film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera system, and particularly to an exposure control and drive system in a camera with interchangeable lenses.

(Prior art) A 35mm camera with non-interchangeable lenses is generally referred to as a compact camera, and this type of camera is equipped with a so-called lens shutter device that functions as both a shutter and an aperture as an exposure control device. has been done. Furthermore, it has become common to automatically wind and rewind the film using the camera's power supply.

Furthermore, so-called single-lens reflex cameras with interchangeable lenses also use automatic exposure devices.

Automatic film winding device, automatic focus adjustment device.

Various mechanisms such as an automatic film rewind device are housed within a single camera, and the mechanisms are automatically operated by a single power source. For this reason, since the power supply voltage is limited, complex operations must be performed in a time-series manner to use the power supply efficiently.

In this type of device, a proposal has been made in which power is supplied from the camera side to the lens side through a contact point between the two, and the aperture of the lens is driven by a motor using the power source of the camera. In this type of system, even when the camera's power supply voltage detection circuit checks the voltage and determines that the voltage is higher than the specified voltage, there is dust between the contacts between the camera and the lens. When foreign matter such as dust is present, the contact resistance becomes large, causing a voltage drop while the camera voltage is being transmitted to the lens, and the aperture may not be able to be driven on the lens side.

It appears that an accident can be determined by providing an open switch that detects the open state (initial state) of the aperture and detecting the state of the open switch. However, the above-mentioned contact resistance is unstable, and its resistance value changes even with a slight impact or the like. In other words, the contact resistance is small in the initial state of aperture operation, that is, during the period of time when the open switch is switched, and if the contact resistance increases during the period after the open switch is switched and the desired aperture value is reached, the aperture is activated. After the driver switches the open switch, the aperture drive motor loses synchronization, making it impossible to narrow the aperture to the desired aperture value, but there was no means to detect this accident.

Furthermore, even when there is no change in contact resistance, the aperture drive motor generally accelerates and decelerates to shorten the aperture control time, but in this case, the step interval is wide near the start of aperture control, so the power supply voltage Even if the voltage decreases a little, there is no problem with the operation of the aperture drive motor, and the open switch can be switched normally, but if the aperture drive motor is accelerated and the step interval becomes shorter, a slight voltage drop may occur. However, there is a possibility that the aperture drive motor may lose synchronization.

As explained above, even if the power supply voltage on the camera side is determined to be above a predetermined value, the aperture may not be activated due to the above-mentioned accident, or the aperture may not be narrowed down to the desired aperture value. There was a problem in that people were unable to take pictures with proper exposure and wasted film because they were unable to take pictures without noticing.

(Purpose) The present invention solves the drawbacks of the above-mentioned conventional example, and provides a camera system in which power is supplied from the camera to the lens through a contact point between the two, and the lens aperture is driven by a motor, while the lens aperture is being driven. The power supply voltage is checked at the same time, and if it is determined that it is above a predetermined value and that the aperture is operating normally, the shooting sequence can proceed, so the power supply voltage drops and the photographer To provide a camera system that notifies a photographer of the occurrence of an accident, such as when a desired aperture value cannot be set or when the aperture is completely inactive, and allows the photographer to concentrate on photographing operations with peace of mind without wasting film. The purpose is to

[Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a configuration diagram schematically showing the configuration of main parts of an electric drive device and circuit for a camera and a lens according to the present invention.

1 is a camera body; 2 is an interchangeable lens body detachably attached to the camera body 1; 63 is a mirror;
4 is a pentaprism, 5 is an eyepiece lens, and 6 is a light receiving element for photometry. 7 is a photometric calculation circuit, and a film sensitivity information input circuit 8. Shutter control circuit 9. Connected to microcomputer 0. 34 is a focal brain shutter.

3a is a mirror rotating shaft, and 3b is an operating bin, which faces the mirror drive cam 11. , 12 are mirror drive motors connected to a motor drive circuit 13. Reference numeral 14 denotes a film winding and rewinding motor, which is connected to a motor drive circuit 15. 16 is a ranging sensor and a ranging calculation circuit 17
It is connected to the. 18 is the battery that operates the entire camera system, 19 is the main power switch, and 20 is the DC
The battery 18 is connected to the microcomputer 10 by a /DC converter.

21 is a photometering and distance measuring switch, and 22 is a release switch. 23a is a group of contact pins on the camera side and is arranged near the mount 1a. 23b is a contact pin group on the lens side, which faces the contact pin group 23a on the camera side. G1 and G2 form a photographing optical system 25, which is an electrically driven diaphragm 24 which is a photographing optical lens and has a built-in diaphragm driving motor (not shown). Reference numeral 26 denotes a lens drive motor used for focus adjustment, which is connected to a lens drive circuit 27, has a gear 26a attached to its output shaft, and is interlocked with a pulse plate 28. A photoreflector 29 is placed opposite the pulse plate 28 and connected to the waveform shaping circuit 3o. 3
1 is an aperture drive circuit connected to the microcomputer 32.
has been done. 33 is an aperture open detection switch connected to the microcomputer 32.

Furthermore, 35 and 36 are voltage detection circuits, one voltage detection circuit 35 is connected between the microcomputer 10 and the battery 18, and the other voltage detection circuit 36 is connected between the microcomputer 32 and the aperture drive circuit 31. ing.

Next, the operation of the camera system of the present invention having the above configuration will be explained.

First, turn on the main power switch 19 of the camera body 1.
By activating the C/DC converter 2o, the converter 20 supplies a constant voltage that allows the microcomputer 1° to operate. When the photometric and distance measuring switch 21 is pressed down, the amount of light detected by the photometric light receiving element 6 is transmitted to the photometric calculation circuit 7, and the exposure amount is stored using a known method.

On the other hand, the photometric distance measurement switch 21 also serves as a trigger switch for automatic distance measurement. When the photometric and distance measurement switch 21 is pressed down, the distance measurement sensor 16 is activated according to instructions from the microcomputer 10, and the distance measurement calculation circuit 17 performs distance measurement calculation using a known method, determines the amount of lens extension, and determines the amount of lens extension. It performs well-known serial communication with the microcomputer 32 of , instructs the lens drive circuit 27 to rotate the drive motor 26, and moves the photographing optical system 25 in the optical axis direction.

At the same time, the pulse plate 28 rotates in response to the movement of the lens, and the amount of movement of the lens can be detected by reading the number of pulses with the photoreflector 29, so that images can be taken according to the amount of movement instructed by the camera as described above. The optical system 25 is moved and the lens is stopped at the in-focus position. Generally, the distance is measured again, and if it is determined that the object is in focus, the camera displays an in-focus indication or generates an in-focus sound.

Next, the subsequent operations will be explained with reference to the timing chart shown in FIG. 2, but the operations up to now are performed before the 0 point in FIG. 2. In FIG. 2, the horizontal axis shows time and the vertical axis shows each item.

When the release switch 22 is pressed down at point 0 in FIG. 2, the microcomputer 1o energizes the motor drive circuit 13 to rotate the mirror drive motor 12, rotates the mirror drive cam 11, and pushes the operating pin 3b. By raising the mirror (point a), the mirror is raised and held (point d). At point b, which is delayed by a certain amount of time from point a, well-known serial communication is performed between the camera microcomputer 1o and the lens microcomputer 32 via the contact pin group 23a, '23b, and the aperture setting value is determined according to the amount of photometry. to the lens. The aperture setting value instructed by the camera controls the electrically driven aperture 24 by the aperture drive circuit 31. At this time, a certain time difference is set between the mirror raising operation point (point a) and the aperture drive operation point (point b) because a large current flows through the mirror drive motor 12 immediately after the power is turned on. The limited power supply is effectively utilized by avoiding the need to drive the aperture. Also, before point b, the aperture open detection switch 33 is in the oven state, and after point b, that is, at the same time as the aperture starts, the detection switch 33 is in the closed state, and it is difficult to determine whether or not it is in the open state. Is going.

Although the aperture opening detection switch 33 is described as a mechanical on-off switch in the embodiment, it may also be other state detection switches, such as an MR element.

You may use different types of photo sensors depending on the situation.

At point 0, the aperture has been stopped down to the set aperture. When the mirror has finished rising at point d, the exposure operation starts from point e, with a slight margin.
That is, the shutter is operated up to point f. At point f, the mirror drive motor 12 is started to be energized based on the exposure completion signal to lower the mirror 3 to 0, and at point g the mirror 3 is returned to a photometry-enabled state. At that time, the mirror drive motor 12 is energized for the same reason as when raising the mirror 3, and after a certain period of time,
Return driving of the diaphragm is started from point h, and when the diaphragm is fully returned to the open state, the diaphragm open detection switch 33 is opened. This is point i. The mirror drive motor 12 also serves to mechanically charge the focal plane shutter 34, and operates up to three points. Said i
The point signal is communicated to the microcomputer 10 on the camera side via the microcomputer 32, and an operation command is issued to the motor drive circuit 15, so that the film is wound by the film winding/rewinding motor 14.

This film winding operation is completed at this point, and the camera sequence returns to normal and moves on to light metering and distance measuring operations.

What has been described above is a series of photographing operations of the camera system of the present invention, but a more complete sequence regarding the electrically driven aperture will be described below using the flowchart shown in FIG.

In FIG. 3, in step 51 the main power switch 1 is
9 is turned on, the DC70C converter 20 is activated in step 52, and the microcomputer 1 is activated in step 53.
Activate 0 and 32. In step 54, the aperture open detection switch 33 detects whether the electrically driven aperture 24 is open or not. If the aperture blades are not opened due to some reason coming out into the optical path, in step 55 the aperture drive circuit 31 returns to the aperture drive circuit 31. When the aperture opening detection switch 33 detects that the aperture is in the open state in step 56, the returning drive of the aperture blades is stopped. As described above, the diaphragm is opened by closing the main power switch 19 of the camera. Here, when it is determined that the aperture will not return to the open state, when the number of return pulses exceeds a certain value, the energization is terminated and a reset message is displayed on the camera.

Next, in step 57, the photometric and distance measuring switch 21 is turned on, and in step 59, the state of the aperture is checked. Step 59
The operations from steps 54 to 61 are the same as those from steps 54 to 56 described above, so their explanation will be omitted here. After photometry and A/D conversion are performed in step 62, the calculation results are stored in step 63. In step 64, the release switch 22 is turned on, and in step 65, the mirror drive motor 12 is rotated to raise the mirror 3. At the same time as the mirror drive motor 12 starts to be energized, a timer (not shown) starts operating, and after waiting for a certain period of time in step 66, in step 67, the power supply voltage inside the camera is checked by the voltage detection circuit 35, and the voltage is set to a predetermined voltage. If the value is less than or equal to the predetermined value, wait for a certain period of time in step 68, or if the value is greater than or equal to the predetermined value, proceed directly to step 69.
In step 69, it is determined whether the aperture to be controlled can be left open or whether it is necessary to reduce the aperture. Here, if the aperture can remain open, the process proceeds to step 81, which will be described later, but if it is necessary to close down the aperture, the number of aperture pulses is transmitted from the camera to the lens in step 70.

In step 71, the number of pulses transmitted from the camera is stored in the register of the microcomputer 32 of the lens, and in step 72, the number of pulses sent from the camera is stored in the register of the aperture open detection switch 33.
The number of run-up pulses unique to each lens from off to open diameter are added and stored.

In steps 73 to 75, the energizing voltage is detected for each pulse, and when it is above a predetermined value, in step 72, when the energizing pulse reaches the number of pulses added, the energizing is stopped in step 76, and the aperture is determined at this point. .

In addition, in the case where the energizing voltage is detected for each pulse as described above, when the voltage is below a predetermined value, or when the aperture is not stopped down and remains open, an abnormal state is reported from the lens to the camera in step 77, and in step 78, the camera's micro the computer 10 causes the mirror to remain in the mirror-raised state;
In step 79, the sequence is stopped and the photographer is notified of the accident.

Further, when the aperture is stopped down, the aperture open detection switch 33 is closed, and it is determined in step 80 whether or not the switch 33 is closed, and if the open switch 33 is closed, the shutter front curtain is activated in step 81. In step 82, the shutter rear curtain is started, and in step 83, based on the shutter rear curtain travel completion signal, the mirror drive motor 12 is energized in step 84 to lower the mirror, and at the same time, a timer (not shown) is activated. ) and step 8
After a certain period of time has elapsed in step 5, an aperture opening command is output in step 86 to start driving the aperture in the return direction. Step 8
7 to confirm that the aperture open detection switch 33 is in the open state, and at the same time start driving the film winding and rewinding motor 14 in step 88. In step 89, it is detected that winding is complete and the series of photographing sequences ends. I will do it. The subsequent sequence returns to step 57 where the photometry switch is turned on.

If the aperture controlled in step 69 is not fully open, steps 70 to 8o are passed and the shutter front curtain start shown in step 81 is performed, and the above sequence is then proceeded.

Next, FIG. 4 shows a second embodiment of the present invention, and is a flowchart similar to that of FIG. 3, and constituent elements similar to those of the first embodiment are designated by the same reference numerals and their explanations will be omitted. Further, the second embodiment is similar to the first embodiment in that the energizing voltage is detected for each pulse, but the explanation thereof will be omitted below.

In FIG. 4, in step 71, the number of pulses transmitted from the camera is stored in the first register of the microcomputer 32 of the lens. In step 9o, a value obtained by adding one pulse to the number of run-up pulses specific to each lens for driving the aperture from the open state of the aperture open detection switch 33 to the aperture diameter is stored in the second register of the microcomputer 32. In step 91, the aperture drive motor is energized in the direction of the small aperture from the open state equal to the number of pulses stored in the second register, and in step 92, the approach section from the open state of the aperture open detection switch 33 to the open diameter is completely energized. When the process is finished, the power supply is terminated. Furthermore, in step 93, the process waits for several milliseconds to wait for the delay time of the aperture drive motor and aperture drive mechanism of the electrically driven aperture 24.

In step 80, as in the first embodiment, it is determined whether the aperture open detection switch 33 remains in the open state or is in the closed state. It is guaranteed that the aperture is stopped by being driven by the pulse, but if it is in the open state, an abnormal state is reported from the lens to the camera in step 77 as in the first embodiment, and in step 78 the mirror remains in the completed state. Then, in step 79, the sequence is stopped and the photographer is notified of the accident. Further, when the aperture open detection switch 33 is in the closed state in step 8o, the process proceeds to step 94,
Here, in step 71, one pulse is subtracted from the number of pulses stored in the first register and stored. In step 95, the aperture drive motor is energized in the direction of the small aperture by the stored number of pulses, and in step 96, the iris drive motor is energized. finish. Thereafter, the sequence of steps 81 to 89 is performed in the same manner as in the first embodiment.

As explained above, in the second embodiment, whether or not the aperture open detection switch 33 is closed is detected at the time when the aperture is driven by one pulse from the open diameter. Since the detection is performed at the time when the switching occurs, the detection time is actually the one that prompted the change, and the detection accuracy can be further improved.

〔Effect of the invention〕

As explained above, according to the present invention, in a camera system in which power is supplied from the camera to the lens through the contact between the two and the aperture of the lens is driven by a motor, the voltage detection circuit of the camera detects that the voltage exceeds a predetermined value. Even if it is determined that this is the case, the voltage on the lens side is checked every time one pulse is sent while the aperture drive motor is energized, and it is determined whether or not the aperture that should be further narrowed down does not remain open when this voltage exceeds a predetermined value. However, by making it possible to proceed with the shooting sequence only when it is determined that the aperture is apertured, the photographer may not be able to set the aperture to the desired value due to a drop in the power supply voltage.
It is possible to prevent an accident such as a malfunction of the diaphragm from occurring and wasting film by performing a photographing operation without noticing the occurrence of an accident.

In particular, when power is supplied from the camera to the lens through the contacts between the two, accidents such as poor contact due to foreign objects intervening between the contacts, and mechanical accidents with the aperture.

Although motor accidents and the like are fully assumed, the photographing sequence is only allowed to proceed when everything is determined to be normal, making it possible for the photographer to concentrate on the photographing operation with peace of mind.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, and FIG. 1 is a block diagram schematically showing the configuration of the main parts of the electric drive device and circuit for the camera and lens, and FIG. 3 is a timing chart, FIG. 3 is a flowchart, and FIG. 4 is a flowchart showing a second embodiment of the present invention. 1 -----------1 camera body 2 ---------1 interchangeable lens body 7 -----1 light metering calculation circuit 18 --------1 battery

Claims (1)

[Scope of Claims] Consisting of a camera body and an interchangeable lens body that is detachably attached to the camera body, the camera body contains a power source and photometry calculation means, and the interchangeable lens body contains electricity supplied from the power source. The camera system is equipped with an exposure amount adjustment device controlled by an optical signal, and the exposure amount adjustment device is driven by a drive circuit in accordance with the number of pulses corresponding to the aperture diameter set by the photometric calculation means. The device includes a voltage detection circuit that detects a voltage during driving of the drive circuit, and a determination circuit that determines whether or not the exposure amount adjustment device is activated, and the voltage detected by the voltage detection circuit is determined to be a predetermined value. A camera system characterized in that the photographing sequence can be advanced only when it is determined that the exposure value is equal to or greater than a value and that the exposure adjustment device is activated.