JP2625701B2 - Optical accessories for cameras - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical accessory for a camera of a camera.
More particularly, the present invention relates to a camera optical system accessory having a built-in communication device for communicating information with both a camera body and a photographing lens.

(Background of the Invention) FIG. 2 shows a state of transmission of information of a conventionally proposed teleconverter having a built-in communication function.

In the configuration shown in the figure, for example, when the open F-number of the taking lens is stored in the CPU 11 of the taking lens 1, the CPU 21 of the teleconverter 2 transmits the information to the CPU 11 of the taking lens 1.
From the camera body 3 and transmitted to the CPU 31 of the camera body 3. At this time, when the teleconverter 2 is mounted, the actual open F value increases by the magnification of the teleconverter 2. Therefore, the CPU 21 of the teleconverter 2 can have the function of correcting the open F value and transmitting the corrected value to the CPU 31 of the body 3.

Also, at the time of auto focus, if there is no teleconverter 2, the CPU 3 uses the distance measurement information from the distance measurement sensor 32.
1 calculates the amount of displacement of the focal plane and transmits it to the CPU 11 of the photographing lens 1, and the CPU 11 of the photographing lens 1 operates the lens actuator 12 to move the lens 13 according to the value, thereby performing the autofocus operation. . However, in the case where the teleconverter 2 is provided, the displacement amount of the focal plane and the movement amount of the lens 13 do not have a one-to-one correspondence, and there is a possibility that autofocusing cannot be performed as it is. The focal plane displacement transmitted from the CPU 31 of the body 3 is corrected and transmitted to the CPU 11 of the photographing lens 1.

Therefore, when such a teleconverter is installed, the teleconverter functions as if the body is directly connected to the photographic lens, and as if the photographic lens was directly connected from the body side, The photographing lens and the camera body can be configured without being aware of the teleconverter.

However, when the teleconverter is provided with the above-described communication function, communication between the photographing lens and the body is performed once after being stored in the CPU of the teleconverter, so that a time lag occurs in information transmission. Therefore, when urgent information is transmitted, for example, when a command to stop driving the lens is transmitted from the body to the photographing lens, the lens stops at a position shifted from the intended stop position of the lens. was there.

(Object of the Invention) It is an object of the present invention to solve this drawback and to provide an optical accessory for a camera that can quickly cope with urgent information transmission without impairing advanced communication functions.

(Summary of the Invention) The present invention relates to a camera optical system accessory for a camera having a communication function, in which a communication path for directly transmitting information of a camera body and information of a photographing lens without passing through an electric circuit of the camera optical system accessory. A technical point is that a communication path for indirectly transmitting the signal via an electric circuit of the camera optical system accessory is provided.

(Embodiment) FIG. 1 shows a state of information transmission of a teleconverter according to an embodiment of the present invention, wherein 1 denotes a photographing lens having a built-in CPU 11, and 2 denotes a CPU 21 and a communication path switching circuit 23. Shows the built-in teleconverter, 3 is CPU3
1 shows a camera body with a built-in 1.

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

The communication path switching circuit 23 is built in the teleconverter 2 and the CPU 21 can control the intermittent operation. When a switch in the circuit 23 is ON, information communication between the CPU 11 of the photographing lens 1 and the CPU 31 of the body 3 is directly performed between the CPU 11 and the CPU 31, and the switch in the circuit 23 is turned off.
If F, CPU 11 and body 3 of lens 1
Communication of information between the CPUs 31 is performed via the CPU 21 of the teleconverter. And the O of the switch in this circuit 23
N and OFF are controlled by the CPU 21.

As an actual operation, for example, normally, when a switch in the circuit 23 is turned ON, a command to stop driving the lens or the like is issued to the CP of the body 3.
Even if it occurs in U31, it is transmitted directly to the CPU 11 of the photographing lens 1 without passing through the CPU 21 of the teleconverter 2, so that a quick response is possible as compared with the conventional method of passing through the CPU 21. In addition, the case where information that needs correction by attaching a teleconverter is communicated is as follows. For example, when the CPU 31 transmits the amount of displacement of the focal plane to the lens side, the CPU 31 first transmits that the information needs correction to the CPU 21 of the teleconverter, for example, as a command. The switch is turned off and the permission of information transmission is notified to the CPU 31 of the body 3. Then, the CPU 31 transmits the displacement amount of the focal plane to the CPU 21 of the teleconverter 2, and the CPU 21 corrects the information and transmits the correct lens movement amount to the CPU 11 of the photographing lens 1. At this time, the command that the correction is necessary is also transmitted to the CPU 11 of the photographing lens 1, but the CPU 11 may be configured to ignore this command.

(Effects of the Invention) As described above, according to the present invention, a communication path and a camera optical system for directly transmitting information of a camera body and information of a photographing lens without passing through an electric circuit of a camera optical system accessory. Since the communication circuit for indirectly transmitting the information via the electric circuit of the accessory is formed, it is possible to provide a teleconverter capable of promptly dealing with urgent information transmission without impairing advanced communication functions.

[Brief description of the drawings]

FIG. 1 shows a state of information transmission of a teleconverter according to an embodiment of the present invention, and FIG. 2 shows a state of information transmission of a teleconverter having a conventionally proposed communication function. It is. (Explanation of reference numerals of main parts) 1... Photographing lens, 2... Teleconverter 3... Camera body, 11; 21; 31.

Claims (1)

(57) [Claims] 1. An optical system for a camera which is mounted between a camera body and an interchangeable lens detachably mounted on the camera body and has an electric circuit built therein for connecting a communication circuit of the camera body and a communication circuit of the interchangeable lens. An accessory, wherein the electric circuit comprises: (a) intermediate information processing means for processing and transmitting received information; and (b) a communication circuit of the camera body and a communication circuit of the interchangeable lens, wherein the intermediate information (C) connecting a communication circuit of the camera main body and a communication circuit of the interchangeable lens to each other without indirectly connecting the intermediate information processing means; A second communication means for forming a second communication path for direct connection; and (d) switching means for selectively switching between the first communication means and the second communication means. Optical system for camera Kessari.