JPH0619488B2 - Automatic focus adjustment adapter for interchangeable lenses − - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an autofocusing adapter, and more particularly to an autofocusing adapter that includes a conversion lens that is driven for focus adjustment and that is provided between an interchangeable lens and a camera body. Regarding

BACKGROUND OF THE INVENTION A device of this type is disclosed in Japanese Patent Application Laid-Open No.
No. 8-168023. The automatic focus adjustment adapter (hereinafter referred to as an adapter) disclosed in this publication will be briefly described. The adapter includes a conversion lens, a motor for moving the lens in the optical axis direction, a focus adjustment control device for driving and controlling the motor, an arithmetic device for outputting a lens signal of the interchangeable lens to the device, and a movement amount of the conversion lens. And a light receiving device for detecting The focus adjustment control device of this adapter rotates the motor based on the detection signal corresponding to the image plane deviation amount and the direction of the deviation sent from the focus detection device on the camera body side. The conversion lens moves in the optical axis direction as the motor rotates, and the amount of movement is fed back to the arithmetic unit as a lens movement amount signal converted into a pulse signal by the light receiving device. Further, a lens signal including at least focal length information of the interchangeable lens is input to the arithmetic device via the terminal of the adapter. The arithmetic unit calculates an image plane movement amount corresponding to the movement amount of the conversion lens with respect to the attached interchangeable lens from the two signals of the lens signal and the lens movement amount signal. Since the calculation result is the corrected lens movement amount signal, the focus adjustment control device compares the image plane deviation amount detected by the focus detection device, and when they become equal, the focus adjustment control device stops the motor. . Therefore, the conversion lens stops at that position, and the focus adjustment is completed.

As described above, since the conversion lens of the adapter is moved by the focus adjustment control device and stopped at the in-focus position of the subject, the conversion lens always stops at different positions. Therefore, this adapter is used as a normal teleconverter (that is, the conversion lens is fixed and the focus is adjusted by the distance ring of the interchangeable lens).
In order to function as a conversion lens, it is necessary to set the stop position of the conversion lens to a position where it can focus to infinity, but as described above, the adapter moves the conversion lens and adjusts the focus. There is no guarantee that the car will always stop in place. Therefore, even if the distance ring of the interchangeable lens is moved to any position, inconvenience cannot be achieved or inconvenience cannot occur.

(Object of the Invention) An object of the present invention is to solve this drawback and to provide an automatic focusing adapter for an interchangeable lens, which has a function such as a normal teleconverter or a close-up ring.

(Summary of the Invention) The present invention is technically configured such that the conversion lens is automatically set to a predetermined position when the automatic focus adjustment adapter for the interchangeable lens is attached to or detached from the camera body or the interchangeable lens. The point is.

(Embodiment) FIGS. 1 to 3 show an embodiment of the present invention. FIG. 1 shows a camera in which an automatic focus adjustment adapter for an interchangeable lens (hereinafter referred to as an adapter) has an interchangeable lens and a focus detection mechanism. FIG. 2 is a side view of the adapter when it is attached to the body, FIG. 2 is a sectional view of the adapter, and FIG. 3 is a perspective view of the adapter and the interchangeable lens when they are attached and detached.

The distance ring 2a of the interchangeable lens 2 shown in FIG. 1 is generally set to an infinite (∞) position, and the interchangeable lens 2 is attached to the camera body 3 to which the adapter 1 is attached via the adapter 1. This adapter 1 is composed of a conversion lens and its driving unit 1b.
The drive mechanism of (1) operates according to the instruction of the detection signal from the known focus detection mechanism in the camera body 3 to automatically drive the conversion lens to perform focus matching. The distance ring 2a of the interchangeable lens 2 may be generally placed at an infinite position,
Interchangeable lens 2 with very close shooting distance
In the case of a long focus system, since the amount of movement of the image plane from infinity (∞) to the close distance is large, it may not be possible to cover only by moving the conversion lens in the adapter 1, that is, focus matching may be impossible. In such a case, by moving the distance ring 2a of the interchangeable lens 2 from the infinite position to the close-up position, the adapter 1 shifts the focus range to the close-up side to enable focus matching. The drive unit 1b of the adapter 1 is located below the conversion lens and projects toward the side on which the interchangeable lens 2 is mounted. The focus lock button 9 is arranged on the side surface of the portion of the drive unit 1b that protrudes toward the interchangeable lens 2, and when the button 9 is pressed, the drive mechanism is forcibly stopped and the conversion lens can be temporarily stopped. . The focus lock button 9 is arranged at such a position so that when the adapter 1 is mounted between the interchangeable lens 2 and the camera body 3, the focus lock button 9 is located at an appropriate distance from the camera body 3 (that is, the camera body 3). This is because it is arranged at a distance from the front surface of the body 3 to the extent that 3 or 4 fingers of the left hand supporting the lower part of the adapter 1 can be placed, and has good operability when holding the camera.
The internal configuration of the adapter 1 will be described with reference to FIG. The ball race 18 is supported by the camera-side mount 10 and the pressing ring 37, and is for smoothly and accurately rotating the open F-number interlocking lever 14, and is composed of a plurality of balls and arranged in the circumferential direction. Has been done. The ball race 19 is supported by the press rings 37 and 38 and is used to smoothly and accurately rotate the automatic diaphragm interlocking lever 16. The ball race 19 is composed of a plurality of balls and is arranged in the circumferential direction. There is. Drive unit 20a
Is attached to the fixing plate 22 fixed to the fixing member 21 with the anti-vibration rubber 2
The drive unit 20a is prevented from being directly transmitted to the lens barrel portion to generate noise by being fixed by the screw 24 through the screw 3. Since the fixing plate 22 is a separate member from the fixing member 21, it is possible to adjust and fix the axial distance between the output gear 25 and the focus gear 26. The drive unit 20a includes a motor, an electric circuit that controls the reduction gear train and their drive systems, a pulse generator that generates a pulse proportional to the movement amount of the conversion lenses 8a to 8e, a pulse detector that detects the number of pulses, and the like. Composed of. The electric circuit 20b constitutes a part of the electric circuit of the unit 20a. The rotation of the focus gear 26 is transmitted to the helicoid ring 30 through a pin 29 fixed to the helicoid ring 30 by a lever 27 fixed to the focus gear 26, and the helicoid ring 30 and the lens barrel 39 are connected by a helicoid screw. Because of the meshing, the helicoid ring 30 translates along the lens barrel 39 in the optical axis direction. Since the lens chamber 31 is fixed to the helicoid ring 30, the lens chamber 31 also moves in the optical axis direction, and the lenses 8a to 8e fixed to this also move in the optical axis direction.

The washer 33 is interposed between the helicoid ring 30 and the lens chamber 31 to adjust the positions of the lenses 8a to 8e during assembly. The ring 34 prevents the helicoid screw portion of the lens barrel 39 from being visible from the outside when the lenses 8a to 8e move to the right in the figure, and dust or the like is attached to the helicoid screw portion to cause the lenses 8a to 8e. It prevents the trouble of driving. Lenses 8a-8e
The limit position of the driving range (from the ∞ position to the closest position) is determined by the electrical output signals of the brush 32 fixed to the focus gear 26 and the electrode pattern 41 fixed to the lens barrel 39, and at that limit position. It is configured to stop or reverse. The switch 36 is the drive unit 20a.
And 20b are on / off switches for the power source of the electric circuit system, and can be turned on / off by sliding from the outside. When the adapter 1 is used by mounting it between the interchangeable lens 2 and the camera body 3 having a built-in focus detection mechanism,
The detection signal of the focus detection mechanism controls the drive units 20a and 20b via contact pins with the camera body 3 side (not shown) provided on the protection ring 13 of the lenses 8a to 8e to automatically control the lenses 8a to 8e. Can be driven for focus adjustment. This contact pin (not shown) is used for the camera body 3
Is an electrical contact for transmitting and receiving various signals to and from the camera body 3. The photographing magnifications of the lenses 8a to 8e are those obtained by multiplying the magnification of the interchangeable lens 2 alone by a specific magnification. As you can see from Figure 2,
By arranging the lenses 8a to 8e at the right rear side with respect to the mount surface of the interchangeable lens mount 6, it is possible to provide a space in the space from the lens 8a to the mount surface, so that the number of interchangeable lenses can be increased. As a result, the adapter 1 can be made highly versatile.

The adapter 1 shown in FIG. 3 is seen from the direction of arrow P in FIG. 2, and the detailed structure is omitted. Similarly, the interchangeable lens 2 is not shown for the fine structure. The conversion chambers 8a to 8e are held in the lens chamber 31 of the adapter 1 and
A seat ring 52 is fixedly provided on the end surface 31a of the first interchangeable lens 2 on which the lever 51 is provided.
It is rotatably supported around an axis E parallel to the optical axis O of e. Since the lever 51 has a click (not shown) between the lever 51 and the seat ring 52, the lever 51 does not rotate about the axis E unless a predetermined tangential force acts on the operated portion 51a.
Therefore, even if a tangential force below a predetermined value acts on the actuated portion 51a of the lever 51, it does not rotate about the axis E. Therefore, when the tangential force below the predetermined value is applied, both the lever 51 and the lens chamber 31 are exposed It will rotate around the axis O. In the embodiment, the returning means of the present invention is composed of a lever 51, a seat ring 52 and a click (not shown).

The lens 56 of the interchangeable lens 2 is held by a lens chamber (not shown), and a protective ring 57 for protecting the lens 56 is provided behind the lens chamber. The protection ring 57 has an adapter 1 when the interchangeable lens 2 is attached to the adapter 1.
The protrusion 57a is provided so as to come into contact with the lever 51.

Next, the operation of the embodiment will be described. In FIG. 3, when the interchangeable lens 2 is attached to the adapter 1 attached to the camera, first the interchangeable lens 2 is inserted into the adapter 1 from the A direction and then rotated in the B direction. Then, the interchangeable lens 2 is fixed to the adapter 1 by a bayonet mount (not shown). At that time, when the interchangeable lens 2 is rotated in the B direction, the end surface 5 of the projection 57a provided on the interchangeable lens 2 is rotated.
7b abuts on the end surface 51b of the actuated portion 51a of the lever 51 provided on the adapter 1 so that the lever 51 and the lens chamber 3
1 is rotated around the optical axis O. When the interchangeable lens 2 is rotated by a predetermined angle, the lens chamber 31 of the adapter 1 comes into contact with a not-shown limiting member on the infinity side to prevent the lens chamber 31 from rotating, and the conversion lens of the adapter 1 moves to infinity. It is in a focusable state, that is, the conversion lens is closest to the interchangeable lens 2 side. If the conversion lens of the adapter 1 is in this state, it functions as a normal teleconverter, and if the distance ring of the interchangeable lens 2 is set to the infinity position, the focus can be adjusted to infinity.

Further, when the interchangeable lens 2 is rotated, the protrusion 57a of the interchangeable lens 2 becomes the end surface 51 of the operated portion 51a of the adapter 1.
Since b is further pressed, the end surface 51b of the operated portion 51a is
When the tangential force applied to the lever exceeds a predetermined value, the lever 51 is rotated around the axis E in the C direction. Then, when the protrusion 57a gets over the lever 51 and rotates to a predetermined position, rotation is prohibited by an attachment / detachment pin (not shown) of the adapter 1 and the attachment of the interchangeable lens 2 is completed. The lever 51 has a protrusion 57a.
When the vehicle has finished overcoming, the original position (the longitudinal direction of the acted part 51a and the optical axis direction of the optical axis O are substantially orthogonal to each other) is restored. Therefore, the conversion lens of the adapter 1 can be used as a normal teleconverter before being driven for the original automatic focusing. Even if the adapter 1 is used for the original automatic focus alignment and the lens chamber 31 of the adapter 1 rotates for focus alignment and the lever 51 rotates, the interchangeable lens is out of the rotation range of the lever 51. Since the second protrusion 57a is located, there is no problem in automatic focusing.

Next, the case where the interchangeable lens 2 is removed from the adapter 1 will be described. First, the attachment / detachment button (not shown) of the adapter 1 is operated to release the engagement of the attachment / detachment pin from the interchangeable lens 2, and then in that state, the interchangeable lens 2 is rotated in the direction opposite to the B direction. When the interchangeable lens 2 is rotated in the direction opposite to the B direction, the end surface 57c of the protrusion 57a contacts the end surface 51c of the actuated portion 51a of the lever 51 to rotate the lever 51 and the lens chamber 31 around the optical axis O. Let Then, when the interchangeable lens 2 is rotated to a predetermined angle position, the lens chamber 31 which is rotating together is brought into contact with a not-shown limiting member on the near side and stopped. Furthermore, when the interchangeable lens 2 is rotated,
Since the projection 57a of the interchangeable lens 2 further presses the end surface 51c of the operated portion 51a of the adapter 1, the operated portion 5a
The tangential force applied to the end face 51c of 1a exceeds a predetermined value to rotate the lever 51 in the D direction around the axis E. Then, when the protrusion 57a goes over the lever 51 and the interchangeable lens 2 rotates to a predetermined position, the engagement with the bayonet mount (not shown) of the adapter 1 is released and the interchangeable lens 2 can be removed from the adapter 1. . The lever 51 returns to the original position (the position in which the longitudinal direction of the operated part 51a and the optical axis direction of the optical axis O are substantially orthogonal to each other) when the ride over of the protrusion 57a is completed.

Further, as described above, when the interchangeable lens 2 is attached to the adapter 1, the conversion lens is automatically returned to a position in which it can be focused very close (that is, the position where the conversion lens is closest to the camera side). For example, the adapter 1 has a close-up ring-like function, and can focus on a distance closer to the closest distance displayed on the distance ring of the interchangeable lens 2.

Therefore, if the power supply of the motor that drives the conversion lens of the adapter 1 for automatic focus adjustment is consumed and drops, automatic focus adjustment becomes impossible and the conversion lens stops at an unspecified position. The focus adjustment range due to the distance ring of the lens 2 is limited, and a range in which focus adjustment is impossible occurs. However, if the interchangeable lens 2 is attached to the adapter 1 as in the embodiment, the adapter 1 can be used as a teleconverter or a close-up lens, so that it will not be disabled even if the power supply is lost. The adapter 1 can also be used as a teleconverter or a close-up ring for a camera without a focus adjustment mechanism.

The present invention is not limited to the above-mentioned embodiment,
In the embodiment, the mounting of the interchangeable lens 2 is used as a means for automatically setting the conversion lens of the adapter 1 at a predetermined position. However, for example, the detaching of the interchangeable lens 2 or the mounting / removing of the interchangeable lens 2 is used. Can be done by Further, in the embodiment, mechanical means is used as means for automatically setting the conversion lens of the adapter 1 at a predetermined position.
By turning on / off the electrical switch by attaching / removing the interchangeable lens 2 or the camera body 3, the conversion lens is automatically set at a predetermined position by using the lens driving motor. It is also possible to configure.

(Effect of the Invention) As described above, according to the present invention, when the interchangeable lens or the camera body is attached to or detached from the interchangeable lens automatic focus adjustment adapter, the setting means acts to automatically set the conversion lens to a predetermined position. The position allows the photographer to use the adapter as a teleconverter or close-up ring at any time. Also, since this adapter can be used with cameras that do not have an autofocus mechanism, the range of use of the adapter is expanded.

[Brief description of drawings]

1 to 3 show one embodiment of the present invention, and FIG. 1 is a side view when an automatic focus adjustment adapter for an interchangeable lens is mounted between the interchangeable lens and a camera body incorporating a focus detection mechanism. FIG. 2 shows a cross-sectional view of the adapter, and FIG. 3 shows a perspective view when the adapter and the interchangeable lens are attached and detached. (Explanation of symbols of main parts) 1 ... Automatic focus adjustment adapter for interchangeable lens 2 ... Interchangeable lens 3 ... Camera body 8a-8e ... Conversion lens 51 ... Lever 57 ... Protective ring 57a ... Projection

Claims (1)

[Claims] 1. An interchangeable lens mounted between a camera body and an interchangeable lens, comprising a conversion lens movable in an optical axis direction and a lens driving means for driving the conversion lens according to a focus detection signal. In the automatic focusing adapter for use, an interlocking member that engages with an engaging member of the camera body or the interchangeable lens and interlocks with a mounting or dismounting operation of the camera body or the interchangeable lens, the interlocking member including the mounting or An automatic focus adjusting adapter for an interchangeable lens, comprising setting means for automatically setting the conversion lens to a predetermined position in association with only a detaching operation.