JPS63172255A - Camera system - Google Patents

Abstract

PURPOSE:To prevent an electric circuit in a camera from generating inoperation or misoperation due to the drop of power supply voltage by returning a diaphragm to the open side after a prescribed time from the restoration of a mirror to the initial position, and after deciding the opened state, starting the winding drive of a film. CONSTITUTION:In a camera system for transmitting an electric signal from the camera to a lens through contacts 23a, 23b between them, the diaphragm is returned to the open side by a diaphragm driving motor 24 after the prescribed time from the restoration of the mirror to the initial position by the action of a mirror driving means 12, and after deciding the opened state by a diaphragm open detecting switch 33, the winding drive of the film based upon a motor 14 is started. Consequently, the electric circuit in the camera can be prevented from generating inoperation or misoperation due to the drop of the power supply voltage.

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.

[Conventional technology]

A 35 mm 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. Furthermore, it has become common to automatically wind and rewind the film using the camera's power supply. Furthermore, even in so-called single-lens reflex cameras with interchangeable lenses, various mechanisms such as an automatic exposure device, automatic film winding device, automatic focus adjustment device, and automatic film rewinding device are housed in a single camera. The two mechanisms described above are operated automatically by the power source in these places. 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 particular, in recent years it has been proposed to use a motor to perform pre-shooting preparation operations such as film feeding and shutter charging, as well as to drive the aperture. Automatic film winding starts in response to the trailing curtain run completion signal, and as the aperture drive and film feed drive operations overlap, power consumption increases, causing the camera's electrical circuit to malfunction or malfunction, for example. There was a problem. Furthermore, the power supply voltage decreases at low temperatures, which particularly causes the above-mentioned problems.

[Objective] The present invention solves the drawbacks of the conventional example described in 2. In a camera system in which an electrical signal is transmitted from a camera to a lens through a contact between the two, the mirror is moved by the operation of a mirror drive means. returns to its initial position and after a predetermined period of time, the exposure adjustment device returns the aperture to the open side, and film winding is started only after this open state is determined. The purpose is to prevent electrical circuits from malfunctioning or malfunctioning.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block 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
2 is a camera body, and 2 is an interchangeable lens body detachably attached to the camera body 1, and is connected to a camera mount 1a and a lens mount 2a, respectively. 3 is a mirror, 4
5 is a pentaprism, 5 is an eyepiece lens, and 6 is a light receiving element for photometry. 7 is a photometric calculation circuit, which includes a film sensitivity information input circuit 8, a shutter control circuit 9, and a microcomputer 10.
is connected to. 34 is a focal plane shaft, 3a is a mirror rotating shaft, and 3b is an operating pin which faces the mirror drive cam 11. Reference numeral 12 denotes a mirror drive motor, which is connected to the motor drive circuit 3. A film rewinding motor 14 is connected to a motor drive circuit 15. 16 is a distance measurement sensor and distance measurement calculation circuit 1
7 is connected. 18 is the battery that powers the entire camera stem, 19 is the main power switch, and 20 is the DC
/DC converter connects the battery 18 to the microcomputer IO.

21 is a photometry/distance measurement switch, and 22 is a release switch. 23a is a group of contact pins on the camera side and mount 1a
is located near. 23b is a contact pin group on the lens side, which faces the contact pin group 23a on the camera side. G1
and G2 is an optical lens for photographing, which forms a photographing optical system 25 with an electrically driven aperture 24 having a built-in aperture drive motor (not shown). Reference numeral 26 denotes a lens drive motor used for focus adjustment, which is connected to the lens drive circuit 8, 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 30. 3
1 is an aperture drive circuit connected to a microcomputer 32; 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, the main power switch 19 of the camera body 1 is turned on to wake up the DC/DCC/type controller 20, thereby supplying the microcomputer 10 with an operable constant voltage. When the photometering and ranging switch 21 is pressed,
The amount of light detected by the photometric light receiving element 6 is transmitted to the photometric calculation circuit 7, and the amount of exposure is stored in a known manner.

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, the distance measurement sensor 16 is activated according to instructions from the microcomputer 10, and the distance measurement calculation circuit 17 measures and calculates the distance using a known method to determine the amount of aperture of the lens. A well-known serial communication is performed with the computer 32 to instruct the lens drive circuit 27 to rotate the drive motor 2G, thereby moving 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.
The amount of movement of the lens can be detected by reading the number of pulses with the photo reflector 29, so the photographing optical system 25 is moved in accordance with the amount of movement instructed by the camera as described above, and the lens is stopped at the in-focus position. Generally, distance measurement is performed 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 using the timing chart shown in Figure 2.The operations up to now are performed before the 0 point in Figure 2, and in Figure 2, the horizontal axis is time, and the vertical axis is each item. It shows.

When the release switch 22 is pressed down at point 0 in FIG. 2, the microcomputer 10 energizes the motor drive circuit 13 to rotate the mirror drive motor 12, which rotates the mirror drive cam 1 and rotates the operating pin 3b.
The mirror is raised and held (point d) by pushing up (point a), and at point b, which is delayed by a certain period of time from point a, the camera microcomputer 10 and the lens microcomputer 32 connect the contact pin group 23a, 23b, a well-known serial communication is performed to instruct the lens to set the aperture according to the amount of photometry. The aperture setting value instructed by the camera is transferred to the electrically driven aperture 24 by the aperture drive circuit 31.
control. At this time, a certain time difference is provided 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 power is turned on. Limited to lower aperture drive. Power is used effectively. Further, before point b, the aperture open detection switch 33 is in an open state, and after point b, that is, at the same time as the aperture starts, the detection switch 33 is in a closed state, and it is determined whether or not the aperture is in an open state.

Although the aperture open detection switch 33 is described as a mechanical on-off switch in the embodiment, other state detection switches such as an MR element, a photosensor, etc. may be used depending on the situation.

At point 0, the aperture has been stopped down to the set aperture. Mirror at point d”
When the second exposure is completed, the exposure operation is performed from point e, that is, the printer is operated up to point 1, with some margin.

[The mirror drive motor 12 is activated based on the exposure completion signal at the point
energization is started, the mirror 3 is lowered, and at two points the mirror 3 is returned to a state where photometry is possible. At this time, the mirror drive motor 2 is energized for the same reason as in the case of raising the mirror 3, and after a certain period of time, the aperture return drive starts from point h, and when the aperture is completely returned to the open state. Aperture open detection switch 3
3 becomes open.

This is one point. The mirror drive motor 12 also serves to mechanically charge the phononorplane shutter 34 and operates up to one point. The signal at one point is transmitted to the microcomputer 10 on the camera side via the microcomputer 32, and issues an operation command 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 point 1 (point 1), and the camera sequence returns to its original state 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 turned off.
9 is turned on, the DC/DC converter 20 is activated in step 52, and the microcomputer l is activated in step 53.
Activate O 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 come out into the optical path for some reason and are not open, in step 55, the aperture drive circuit 31 returns to the open direction. 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. By closing the main power switch 19 of the camera as described above, the aperture is opened. Here, if it is determined that the aperture will not return to its open state, the energization is terminated when the number of pulses reaches a certain value or less, and a reset message is displayed on the camera.

Next, in step 57, the photometering/distance measuring switch 2 is turned on, and in step 59, the state of the aperture is checked. Step 59
The operations in steps 6 to 6 are the same as those in steps 54 to 56 described above, so their explanation will be omitted here. After photometry and A/D exchange 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.

In steps 66 and 67, the energization is continued until the completion of the mirror 3's ascent is detected, and when the completion of the second ascent is detected, the energization is stopped. Furthermore, in step 65, the mirror drive motor 12
At the same time as the power supply starts, a timer (not shown) starts operating, and after waiting for a certain period of time in step 68, the power supply voltage inside the camera is checked by the voltage detection circuit 35 in step 69, and if it is less than a predetermined voltage, step 70 is performed. After waiting for a certain period of time, if the value is equal to or greater than a predetermined value, the process directly proceeds to step 71, where it is determined whether the diaphragm to be controlled can be left open or whether it is necessary to reduce the diaphragm. Here, if the aperture can remain open, the front curtain of the shutter is started in step 76, which will be described later, but if it is necessary to narrow down the aperture, the number of aperture pulses is transmitted from the camera to the lens in step 72. In step 73, the aperture open detection switch 33 detects whether the electrically driven aperture 24 is open or not. If it is open, in step 4 the mirror is left in the completed state of 1 raising, and in step 75 the sequence is stopped and the user to report the accident.

If the aperture opening detection switch 33 is closed in step 73, the shutter front curtain is started in step 76,
In step 77, the shutter rear curtain is started, and in step 78, based on the shutter rear curtain travel completion signal, in step 79, the mirror drive motor 12 is energized to lower the mirror, and in step 80, it is determined whether the mirror 3 has lowered. If the mirror drive motor 12 is lowered, the mirror drive motor 12 is stopped energized in step 81, and if the mirror drive motor 12 is not lowered, the process returns to step 79. Further, in step 82, a timer (not shown) is activated to wait a certain period of time, and in step 83, the power supply voltage inside the camera is checked by the voltage detection circuit 35, and if it is less than a predetermined voltage, step 84 is performed, after waiting for a certain period of time, a predetermined voltage is set. If the above is the case, the process directly proceeds to step 85, in which a command to open the aperture is sent to the lens, and in step 86
~89, the state of the aperture open detection switch 33 is detected every time the aperture drive motor is energized one pulse in the direction of opening from the small aperture, and when the switch 33 is closed, the number of energized pulses is >00. It is detected whether or not there is an accident, and if it is less than or equal to that, energization is continued, and if it is more than that, the process returns to step 75 to stop the sequence and notify the user of the accident. When the aperture open detection switch 33 is open in step 87, the energization to the aperture drive motor is stopped in step 89, and the drive of the film winding/rewinding motor 14 is started in step 90. At step 91, completion of film winding is detected, and the series of photographing sequences ends. Thereafter, the sequence returns to step 57 where the photometric and distance measuring switch 21 is turned on.

Furthermore, in the two series of flowcharts, mirror 3 is also 1.
During both raising and lowering, the step 68,
After waiting for a certain period of time as shown in 82, the electrically driven aperture 24
As a result, the peak timings of energization of the motors for driving the mirror and driving the diaphragm are shifted. Therefore, it is possible to prevent rush currents from flowing at the same time at the start of energization, and the limited power supply voltage can be utilized extremely effectively. Further, as described above, after waiting for a certain period of time in step 68.82, the power supply voltage is checked in the next step 69.83, and if the voltage is below a predetermined value, the next step 70. 84, but when the voltage of the battery 18 is unexpectedly low due to low temperatures, etc., the timing of the peak power supply to each motor for mirror drive and aperture drive is adjusted. This is to shift it further.

〔Effect of the invention〕

As explained above, according to the present invention, in the camera system as described above, the mirror returns to its initial position by the operation of the mirror driving means, and after a predetermined time, the exposure adjustment device returns the aperture to the open side, and the aperture is adjusted to the open position. Since the film winding drive is started only after the state is determined, it is possible to prevent the electric circuit of the camera from malfunctioning or malfunctioning due to a drop in the power supply voltage.

Furthermore, the time it takes for the mirror to return to its initial position and to activate the exposure adjustment device is made to vary depending on the magnitude of the power supply voltage, so even if the power supply voltage suddenly drops due to low temperatures, etc. It is extremely practical as it can guarantee the operation of the camera.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention,
FIG. 1 is a block diagram schematically showing the main parts of an electric drive device and circuit for a camera and a lens, FIG. 2 is a timing chart, and FIG. 3 is a flow chart. I・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・Camera body 2・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・Interchangeable lens body 7・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・Photometry calculation circuit

Claims (2)

[Claims] (1) Consists of a camera body and an interchangeable lens body that is detachably attached to the camera body. Inside the camera body, there are also a power supply motor, a photometric calculation means, a mirror drive means driven by the motor, and a film winding means. A motor supplied with power from the power supply and controlled by an electrical signal and an exposure adjustment device driven by the motor are disposed inside the interchangeable lens body, and the exposure adjustment device adjusts the aperture set by the photometric calculation means. In a camera system configured to be driven by a drive circuit according to the number of pulses corresponding to the aperture, the mirror returns to its initial position by the operation of the mirror drive means, and after a predetermined time, the aperture is set to the open side by the exposure amount adjustment device. , and the film winding drive is started only after this open state is determined. (2) The camera system according to claim 1, wherein the time taken from when the mirror returns to its initial position to when the exposure adjustment device is activated is varied depending on the magnitude of the power supply voltage.