JP2864378B2 - Power supply method, camera system and camera body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power supply method between a body and a lens.

[Conventional technology]

Electrical contacts are provided on the body and lens when the lens is attached to the body, and data specific to the lens is exchanged between the body and the lens. Based on that data, automatic exposure control and focus detection are possible. .

[Problems to be solved by the invention]

In a body / lens system capable of automatic focus detection and electric zoom, if a power supply is limited to only the lens side when a motor is provided on the lens side, for example, an increase in the lens shape or power supply to the lens side is cut off. Restrictions such as stuck. Therefore, it is very useful to be able to supply power from the body if necessary.However, if power is supplied to the electrical contacts on the body, there is a danger of short-circuiting when the lens is removed because the contacts are exposed. Was. The use of a mechanical switch or the like in conjunction with the mounting eliminates the risk of short-circuiting, but has the drawback that it cannot be supplied only when it is needed on the lens side in addition to the need for a mechanical switch mechanism.

The present invention has been made in view of such a point, and an object of the present invention is to output no power to a contact when not mounted, and to output to a contact only when necessary even when mounted.

[Means to solve the problem]

For the above purpose, in the present invention, only when the lens side needs power based on communication data between the body and the lens, the switching means in the body is operated to supply power to the lens side via the contact point. .

Also, in the present invention, a first electrical contact provided on the taking lens, a second electrical contact provided on the camera body corresponding to the first electrical contact, a power supply provided on the camera body side, And a data generating means for generating communication data with the camera body, and a data generation means provided on the camera body side, in response to the communication data from the imaging lens, to the imaging lens via the first electrical contact and the second electrical contact. The camera system has power supply means for supplying power.

Further, according to the present invention, in a camera body to which a photographing lens having data generating means for generating communication data and an electric contact can be mounted, a camera-side electric contact electrically connectable to the electric contact of the photographing lens, Power supply means for supplying power to the photographing lens in response to the transmitted communication data.

[Action]

In the present invention, the body-lens communication is established by mounting the lens, and the power supply to the lens is controlled by the communication data. Therefore, the power is not output to the contact point when the lens is not mounted.

〔Example〕

FIG. 1 is a configuration diagram of one embodiment of the present invention. The body side power supply 1 is connected to the DC-DC converter 2 in the body,
The stabilized output Vcc of the DC converter 2 is used as a power source for the microcomputer 3 in the body and at a contact A with the lens.
Is output as a power source of the lens microcomputer. Communication lines between body lenses DATA (data line), CLK (clock line), and CTL (control line) are connected by body / lens contacts B, C, and D, and are connected to the microcomputer ports on the body side and lens side, respectively. ing. The contact E is a contact of the ground line. The output port P of the microcomputer on the body side is connected to a resistor 11
The transistor 12 is driven through. The output of transistor 12 drives transistor 14 via resistor 13. The transistor 14 receives the power supply V in the body as an input, and
Switching is performed by the output of 12, and the output V of the power source 1 in the body can be transmitted to the lens contact F.

The operation of the embodiment of the present invention thus configured will be described with reference to the flowchart of the microcomputer in the body shown in FIG. The microcomputer first communicates with the lens using the communication lines DATA, CLK, and CTL (# 1). If the communication is not established, the microcomputer jumps to (# 2) and outputs "L" to the port P. If no lens is attached, communication is not established, and in this case, the process goes through this step. When "L" is output to the port P, the transistors 12 and 14
Is turned off, and no power is output to the lens contact F. (#
When the communication is established in 1), the process proceeds to (# 3), and the lens power supply request bit in the lens data obtained by the communication with the lens microcomputer 17 is tested. If the request bit is 1, proceed to (# 4), output "H" to port P, and proceed to (# 6). When "H" is output to the port P, the transistors 12 and 14 are turned on, and power is output to the lens contact F from the body side. If the lens-side power request bit is 0, the process proceeds to (# 5) and “L”
Is output, and the process proceeds to (# 6). In (# 6), AE and AF calculation and control are executed as necessary based on the lens data obtained by the communication, and the process returns to (# 1). In this example, the power supply request from the lens is a certain bit in a predetermined communication byte, but may be a response to a predetermined command.

〔The invention's effect〕

As described above, in the present invention, the lens
Since the lens communicates and the power supply is controlled to the lens side by the communication data, not only will the power not be output to the contact point when the lens is not mounted, but also the remaining capacity of the battery, for example, will be lost on the lens side If the power supply from the body is requested by the communication data, for example, the power supply can be made in response to the request, which is very effective.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention;
FIG. 2 is a flowchart showing the operation of the embodiment. [Description of Signs of Main Parts] 3 ... Microcomputer on camera body 15 ... Motor 16 ... Motor drive circuit 17 ... Microcomputer on lens side

Claims (3)

(57) [Claims] 1. A camera body and a lens, wherein a plurality of electrical contacts between a camera body and a lens are brought into contact by mounting a detachable lens, and data communication is performed between the body and the lens. Power is supplied from the camera body to the lens via at least one of the electrical contacts in response to communication data indicating that power is required among the data. Power supply method. A first electrical contact provided on the taking lens; a second electrical contact provided on the camera body corresponding to the first electrical contact; a power supply provided on the camera body side; A data generating means provided on the photographing lens side for generating communication data with the camera body; and a data generating means provided on the camera body side and responding to communication data indicating that power is required among the communication data. A power supply unit for supplying power to the photographing lens via the first electrical contact and the second electrical contact. 3. A camera body to which a photographing lens having data generating means for generating communication data and an electric contact can be mounted, wherein a camera-side electric contact electrically connectable to an electric contact of the photographing lens; A power supply unit for supplying power to the photographing lens in response to communication data transmitted from the lens and indicating that power is being requested.