JPH0320819Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a camera that can be combined with a lens having an automatic focusing mechanism or other lenses.

(Prior Art) In recent years, various automatic focus adjustment (hereinafter abbreviated as AF) mechanisms have been proposed, but their features have not yet been fully utilized for single-lens reflex cameras. That is, as is well known, single-lens reflex cameras can be freely attached with various interchangeable lenses from wide-angle to telephoto, and this point is very attractive to users.

(Problem that the invention aims to solve) However, in order to obtain the AF function, it is necessary to provide an AF mechanism on each lens side. This requires a separate start-up operation for the AF mechanism on the lens side, which is cumbersome to operate. Also,
If the camera body is dedicated to AF lenses, operability will be improved, but a special connecting member must be placed between the camera body and the lens, and some sort of switching operation is required when using a general lens without an AF mechanism. A problem arises.

This invention requires a special starting operation for the AF mechanism,
It is an object of the present invention to provide an interchangeable lens camera with excellent operability that does not require a switching operation when using a general lens.

[Structure of the idea]

(Means for Solving the Problems) A camera according to the present invention includes a camera body to which a lens having an automatic focus adjustment mechanism can be removably attached, and a camera body that is provided on the camera body and comes into contact with the lens side when the lens is attached. a terminal section that constitutes a signal exchange circuit, and a release operation section that is provided on the camera body and generates a shutter release output in response to a release signal on the condition that a focus signal is input from the lens side through the terminal section. and when the terminal section is in an open state, the potential of the focus signal input section of the release operation section is made the same as the potential of the focus signal.

(Function) The present invention allows electrical connection between the lens through the terminal section by attaching the lens to the camera body,
Sends and receives various signals for automatic focus adjustment. In addition, when the terminal section on the camera body side becomes open, the same potential as the focus signal from the lens side is applied to the focus signal input section of the release operation section, and when using a general interchangeable lens, No switching operation is required.

(Example) The present invention will be described below with reference to an example shown in the drawings.

In the figure, reference numeral 11 denotes a camera body with interchangeable lenses. This camera body 11 is equipped with a power supply circuit 12, and this power supply circuit 12 has a switch 13 that is closed by the first step operation of a release button (not shown). , a starting input is obtained by closing this switch 13. The output end of this power supply circuit 12 is connected to a display circuit 14 for displaying focus alignment, one input terminal of a NAND gate 15, and an exposure control circuit 16, respectively. The above NAND gate 15 is for AF operation command, and the other input terminal has a winding detection circuit 17 that turns off when film winding is completed.
The output end of is connected. Reference numeral 18 denotes a flip-flop used as a release operation section, and a set terminal S of this flip-flop 18 is connected to a switch 19 that is closed by the second step operation of the release button. The output terminal Q of this flip-flop 18 is connected to the exposure control circuit 16, and its output is applied to the exposure control circuit 16 as a shutter release signal. This exposure control circuit 1
The output of 6 is applied to a shutter drive mechanism (not shown) to operate the shutter. 20 is the terminal part,
It has four terminals 20a, 20b, 20c, and 20d, and when the lens 23 is attached to the camera body 11, it comes into contact with the corresponding terminals 24a, 24b, 24c, and 24d of the terminal section 24 on the lens side, and during this time, Configure a signal exchange circuit. Here, the terminal 20d is connected to the display circuit 14, the terminal 20c is connected to the output terminal of the NAND gate 15, and the terminal 20d is connected to the output terminal of the NAND gate 15.
b is connected to the reset terminal R of the flip-flop 18. The reset terminal R of the flip-flop 18 is also connected to the output terminal of the winding detection circuit 17.

The lens 23 is equipped with an AF mechanism and is equipped with a power supply circuit 25, which has a main switch 26 and is activated when the main switch 26 is turned on. The output terminal of this power supply circuit 25 is connected to the motor control circuit 27 and the focus detection circuit 2.
8, these motor control circuits 27
and supplies power to the focus detection circuit 28. The focus detection circuit 28 measures the distance to an object (not shown) during operation, and outputs a control signal to the motor control circuit 27 in order to match the focus. Then, the motor control circuit 27 controls the motor 2 based on this control signal.
9 is operated to drive a lens barrel (not shown). Further, this focus detection circuit 28 is configured to generate a focus matching signal, and its output terminals are connected to terminals 24b and 24d, respectively.
Furthermore, this focus detection circuit 28 is connected to a terminal 24c and an operation switch 30, respectively, and becomes activated upon receiving a start signal from either of these.

Note that the terminal portion 32 in the figure is connected to a winder side terminal portion 33 when an electric film winding device, so-called a winder, is used.

In the above configuration, during photographing, the main switch 26 is closed, and the motor control circuit 27 and focus detection circuit 28 are powered.
In this state, when a release button (not shown) is operated after winding of the film is completed, the first step operation closes the switch 13 and starts the power supply circuit 12. Therefore, the exposure control circuit 16 performs a photometry operation for adjusting exposure. Further, the NAND gate 15 provides a start signal to the focus detection circuit 28 via terminals 20c and 24c to activate it. Furthermore, the display circuit 14 also enters a standby state.

The focus detection circuit 28 is activated by the above operation, and when the motor 29 is driven via the motor control circuit 27 and the focus is aligned, the focus detection circuit 28 outputs a focus alignment signal. This in-focus signal is transmitted to terminal 24.
It is connected to the display circuit 14 through terminals d and 20d to cause it to emit light to indicate that it is in focus, and is connected to the reset terminal R of the flip-flop 18 through terminals 24b and 20b to reset it. Therefore, the flip-flop 18 is operated by closing the switch 19 by operating the release button in the second stage and applying a release signal to the set terminal S, thereby producing a shutter release output. In other words, even if the release signal is applied to the set terminal S by the second stage operation of the release button, the shutter release operation is prohibited until the focus signal is applied to the reset terminal R.
Therefore, photography is always performed in a focused state.

Next, a case will be described in which a general interchangeable lens without an AF mechanism is attached to the camera body 11 as described above. In this case, since the terminal section 20 is in an open state, the flip-flop 18 is always in a reset state. Therefore, when the switch 19 is closed by the second stage operation of the release button and a release signal is applied to the set terminal S, a shutter release output is generated and the camera can be operated in the same way as a normal camera.

That is, when the terminal section 20 on the camera body side becomes open, the same potential as the focus signal from the lens side is applied to the reset terminal R, which is the focus signal input section of the flip-flop 18, which is the release operation section. Since the circuit is configured as described above, even if a general interchangeable lens is used, it can be used as is without any switching operation.

It should be noted that the present invention is not limited to the above embodiments, and in particular, NAND gates, flip-flops, etc. can be replaced with other circuits having similar functions.

[Effect of idea]

As described above, according to the present invention, by attaching a lens with an automatic focus adjustment function, a signal exchange circuit is constructed between the lens and the lens.
No special starting operation is required for the automatic focus adjustment mechanism, and when the terminal section is open,
Since the same potential as the focus signal from the lens side is applied to the focus signal input section of the release operation section, it is possible to obtain a camera with excellent operability that does not require switching operations when using a general lens. .

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of the camera according to the present invention. DESCRIPTION OF SYMBOLS 11... Camera body, 18... Release operation part, 20... Terminal part, 23... Lens with automatic focus adjustment mechanism.

Claims (1)

[Scope of Claim for Utility Model Registration] A camera body to which a lens having an automatic focus adjustment mechanism can be removably attached, and a signal transmission/reception circuit provided on the camera body and in contact with the lens side when the lens is attached. a terminal section, and a release operating section that is provided on the camera body and generates a shutter release output in response to a release signal on the condition that a focus signal is input from the lens side via the terminal section, the terminal section 1. A camera characterized in that when the camera is in an open state, the potential of a focus signal input section of a release operation section is made the same as the potential of a focus signal.