JP2820254B2 - Camera image stabilizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image blur prevention device for a camera that drives an optical system to eliminate image blur caused by camera shake due to hand shake or the like. is there.

2. Description of the Related Art Conventionally, a control device for preventing image blurring (stabilization of an image) of a camera has been proposed. Generally, a control device for forming an image of a film or the like resulting from vibration of the camera due to camera shake or the like has been proposed. The vibration of the image on the surface is provided as a configuration in which a lens system to be controlled is driven in a direction of suppressing the vibration by a feedback system control mechanism.

For example, a camera shake vibration (usually a tilt vibration of the camera with respect to the photographing optical axis) is detected as an acceleration signal, and the acceleration signal is integrated by a signal processing system to obtain a displacement signal (or a speed signal). The lens system is configured to be driven in a vibration suppression direction (a direction in which apparent vibration of an image is suppressed).

FIG. 10 shows an example of the principle configuration of an image blur prevention apparatus including such a conventional signal processing system. In FIG. 10, reference numeral 1 denotes an accelerometer, and a photographing light of a camera (not shown). The tilt with respect to the axis is detected as an acceleration signal. The detected acceleration signal a is converted into a speed signal v by the first integrator 2.
, And then converted into a displacement signal d by the second integrator 3 and input to the operational amplifier 7.

Reference numeral 5 denotes an actuator, which is an imaging system 4 of a camera which is provided so as to be movable in a radial direction in order to prevent image blurring.
(Usually an imaging lens system) is driven to be driven in the radial direction by the input of the displacement signal d.

Reference numeral 6 denotes a variable resistor which constitutes a position detecting means for detecting an actual position displacement of the image forming system 4, and feeds back a signal from the position detecting means to an input system of the actuator to thereby form the image forming system 4. A feedback loop is configured to make the drive control correspond to the vibration displacement.

Reference numeral 8 denotes an imaging system 4 when the actuator 5 is not operated.
Is pressed against a limit position on one side of the movable range, so that the imaging system 4 does not move unnecessarily when not operating.

In the configuration of this conventional example, the radial position of the imaging system 4 when the actuator is in the operating state is determined by the spring 8
And the force generated by the actuator 5. In order to appropriately provide an image blur prevention operation start operation due to the presence of the spring 8, an imaging system centering means is further provided. Becomes normal.

To briefly explain this, if the total stroke in the radial direction of the imaging system 4 in the above configuration is l and the origin is when the imaging system 4 is at the center position (position of l / 2), the actuator When the lens 5 is not operated, the imaging system 4 is pressed by the spring 8 to the position of -1/2. Next, assuming that the actuator 5 is switched from the non-operating state to the operating state, if there is no centering means, the image forming system 4 starts the image blur preventing operation in a state where the image forming system 4 is kept pressed at the position of -1/2. You have to do it. Then, since the imaging system 4 is at the negative limit position, no further movement in the negative direction can be performed, and a satisfactory image blur prevention effect cannot be expected.

Therefore, in order to allow the imaging system to move arbitrarily in both positive and negative directions by operating the actuator 5,
At the start of the operation of the actuator 5, the imaging system 4 is set to -l / 2.
Means for immediately bringing the position from the position to the origin position (this operation is called centering) is added, and after this centering, control for preventing image blur is started. The time required for the centering operation is ideally preferably set to be as short as possible so as to be zero. However, in practice, the centering operation time of the imaging system 4 and the vibration damping time after the centering are reduced to 30 to 100 msec. It takes some time.

The centering operation is particularly effective immediately before the shutter release operation of a silver halide camera or the like. That is, the anti-shake operation must be effective during film exposure during the release operation. However, if the release operation is started when the imaging system 4 is located at a position deviated from the center of the stroke, the stroke margin is small. For the side,
The imaging system 4 is likely to hit the end of the stroke, and the image blur prevention operation is likely to be invalidated. Therefore, it is desirable to perform the centering operation every time immediately before performing the release operation, bring the imaging system 4 to the center of the stroke, and then start the release operation.

[Problems to be solved by the invention] However, as described above, the centering operation includes
It takes about 30 to 100 msec. If the release operation starts during the centering operation, the imaging system 4 moves regardless of camera shake while the shutter is open and the film is being exposed. There is a problem that an image flowing in the direction in which the imaging system 4 has moved by centering is recorded.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image stabilizing apparatus for a camera which can prevent a shooting error due to a centering operation and can always ensure proper shooting.

Means and Solution for Solving the Problems To achieve the object of the present invention, a gist for controlling a release operation, a shake detection means for detecting a camera shake state, and an output of the shake detection means are described below. An image of a camera, comprising: a shake correcting means for driving an image forming system in response to the shake; and a centering means for moving the image forming system to a substantially central position of a shake correcting range by the shake correcting means. The anti-shake device is provided with a linkage control means for prohibiting the parallel operation of one of the release means and the centering means when one of the release means and the centering means is operated. For example, the centering operation is prohibited during the release operation. Thus, the centering operation is not affected by the photographing.

[Embodiment] Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

Embodiment 1 FIG. 1 is a block diagram showing an embodiment of an image blur prevention device for a camera according to the present invention.

In this embodiment, members having the same reference numerals as those in FIG. 10 are denoted by the same reference numerals, and the operation thereof has already been described.

This embodiment is an example in which the present invention is applied to a single-lens reflex camera,
9 is a quick return mirror, 10 is an aperture, 11 is a shutter, and 12 is a film. 13 is a release control circuit, a parallel I / O ₁ 15, when the release signal is input through the gate circuit 14 becomes L → H, and controls the operation of the quick return mirror 9, aperture 10, shutter 11 , A series of release operations are performed. And it outputs the release operation is completed the release operation end signal to the main CPU (CPU ₁₎ 16 through a parallel I / O ₁ 15. 14 is a gate circuit, which is connected in parallel when the Q output of the flip-flop 21 is H
Limiting the release signal is output to release the control circuit 13 from the I / O ₁ 15.

Reference numeral 15 denotes a parallel I / O _1, which exchanges signals between a main CPU (CPU ₁ ) 16 and a release switch 17, a release control circuit 13, and other switches and circuits (not shown).

Reference numeral 16 denotes a main CPU (CPU ₁ ) which detects that the release switch 17 has been pressed and generates a release signal. It also performs exposure calculations and distance measurement calculations inside the camera.

17 is a release switch, it is connected to the parallel I / O ₁ 15 and the parallel I / O ₂ 19.

Reference numeral 18 denotes a central processing circuit (CPU ₂ ) for an image blur prevention device,
Pressing release switch 17 indicates that parallel I / O ₂ 19
, The centering operation is executed.
19 is a parallel I / O (PI / O ₂ ) which is an interface, the output port of which is connected to a one-shot circuit 20,
The input port is connected to the release switch 17 and the output Q of the RS flip-flop circuit 21. The one-shot circuit 20, the output from the parallel I / O ₂ 19 is "L" →
At the rising edge of “H”, an “H” pulse is output.

Further, the RS flip-flop circuit 21 is set (S)
The input terminal is connected to the output terminal of the one-shot circuit 20,
The reset (R) input terminal is connected to the gate circuit 24. Further Q output is connected a reset input terminal of the integrator 2 and 3 described above, the gate circuit 14 and parallel I / O ₂ 19.

The gate circuit 24 constitutes a priority circuit for removing an unstable state (R input = S input = “H”) of the RS flip-flop circuit 21 and giving priority to the S input.

Reference numeral 22 denotes a reference power supply for centering, which generates a voltage for holding the imaging system 4 at the center (origin position) of the oscillatable range.
Is added to the operational amplifier 7.

Reference numeral 23 denotes a reset circuit for generating a reset output (= "H") when the imaging system 4 comes near the origin position, and its input terminal is connected to the position detecting means 6. , Its output terminal is connected to RS through the gate circuit 24.
It is connected to the R input of the flip-flop circuit 21.

The configuration of the reset circuit 23 will be described in detail. Comparators 23a and 23b output "H" when the input voltage applied to the + terminal is higher than the voltage applied to the-terminal, and output "L" when the input voltage is lower than the voltage applied to the-terminal. 23c and 23d are reference power supplies.

Here, the voltage of the centering reference power supply 22 is V ₂₂ , the voltage of the reference power supply 23c is V _c , and the voltage of the reference power supply 23d is V _d ,
If V _c and V _d are determined so as to satisfy V ₂₂ = V _c + V _d / 2 (1), the voltage V
Is within the range of V _c <V <V _c + V _d (2), that is, only when the output of the comparator 23a is “H” and the output of the comparator 23b is “L”, The output becomes "H".

Next, the operation of the present embodiment device having the above configuration will be described. FIG. 2 is a flowchart illustrating an operation procedure in the CPU ₂ of the image blur prevention device.

Note that, as described above, it is desirable that the centering operation be performed at the start of the operation of the image blur prevention device and at the time of the release operation. When started (001), until after first initializing the image vibration prevention apparatus CPU ₂ 18 is (002), whether the image blur prevention start SW (not shown) is depressed (003), the release switch 17 is depressed (004 ), Repeat the loop. When the image blur preventing activation switch or release switch 17 is pressed, CPU ₂ 18 is the output of the parallel I / O ₂ 19 to "H" (00
5) to initiate the centering operation by the main CPU16 is a release signal from the parallel I / O ₁ 15 to "H". At this time, the main CO
The U16 is configured so that there is a time lag by software from when the release switch 17 is turned on to when the release signal is generated.

(006): a one-shot circuit 20 outputs the "H" pulse at the time of the rise of the "L" → "H" of the parallel I / O ₂ 19.
The RS flip-flop circuit 21 receiving this "H" pulse enters the set state, and its output Q becomes "H". Output Q
Becomes "H", the integrators 2 and 3 are reset and their outputs become 0, so that the command voltage applied to the operational amplifier 7 is only the voltage from the centering reference power supply 22. On the other hand, a position feedback operation toward the position designated by the voltage of the reference power supply 22, that is, the origin position of the imaging system 4 works, and this is the centering operation. When the Q output of the RS flip-flop circuit 21 is "H", the release signal to the release control circuit 13 is restricted by the gate circuit 14, so that the release operation is not performed and the release operation is prohibited.

(007): The centering operation causes the imaging system 4 to sufficiently approach the origin position, which is the target position, and the position detection means 6
When the voltage V falls within the range represented by the above equation (2), the output of the reset circuit 23 becomes "H", and at the same time, the output pulse from the one-shot circuit 20 is output and the gate circuit 24 is limited. Unless otherwise, the Q output of the RS flip-flop circuit 21 is reset to “L”. When the Q output becomes "L", the reset inputs of the integrators 2 and 3 also become "L", the displacement signal d is output from the integrator 3, the centering operation ends, and the image blur prevention operation starts. (Resume).
At the same time, since the input to the gate circuit 14 also becomes "L", the restriction on the release signal is released.

(008): In the present embodiment, RS flop flip-flop circuit 21 of the Q CP for preventing image blur an output through the parallel I / O ₂ 19
It is input to the U ₂ 18, Q output in this CPU ₂ 18 is "H" → "L"
Detecting the centering completed by monitoring that has become, so that the lower the parallel I / O ₂ 19 output to "L". Thus, all the centering operations of the image forming system of the image blur prevention apparatus are completed.

In the present embodiment, the entire release operation is configured to be limited. However, when a release sequence is established by a series of operations such as up and down movement of the mirror 9 and aperture stop of the aperture 10 as in a single-lens reflex camera, May be stopped at an arbitrary stage before the shutter is opened.

Embodiment 2 Embodiment 1 is provided with a linkage control means of a type for inhibiting the operation of the release control circuit 13 for controlling the release operation during the centering operation of the image blur prevention apparatus. In the second embodiment described above, the release control operation is prioritized, and when the release operation is started before the centering is completed, the linkage control means is configured to end the centering halfway.

The circuit configuration of the second embodiment differs from that of FIG. 1 in that the reset (R) input of the RS flip-flop 21 is connected to the release control circuit 1.
It is characterized in that it can be controlled by a signal (R ') generated at any time before the shutter is opened during the release operation from 3', for example, a signal indicating the end of mirror up. First
The reference numeral 13 'is used to distinguish the release control circuit 13 from the release control circuit 13 in the figure.

As for the reset (R) input, when either the signal R 'or the output of the reset circuit 23 is "H", the "H" input is given to the R terminal. In this embodiment, the circuit for limiting the release signal at the time of the centering operation in the first embodiment is omitted, but the other circuit configuration is substantially the same as that of FIG.

Similarly to the first embodiment, in the present embodiment, the main CPU 16 detects a press of the release button 17, waits for a predetermined time by software in order to advance the centering operation before the release operation, and then generates a release signal. It is configured as follows. However, in this embodiment, the time required for centering differs depending on how far the imaging system 4 is located from the center of the stroke at the start of centering. When centering is started in an extreme case in which the imaging system 4 hits the end of a stroke, the time required for centering may be longer than the time waiting time of the main CPU 16.

 The operation in such a case will be described.

When the time waiting main CPU16 during the centering operation is completed, a release signal is output from the parallel I / O ₁ 15 relative to the release control circuit 13 '. Release control circuit 13 '
Performs a series of release operations, and sets the R 'signal to "H" after the mirror return of the quick return mirror 9 is completed. At this time, if the centering operation has not been completed, the output of the OR circuit 25 also becomes “H”, and the RS flip-flop circuit 21 is reset. After the RS flip-flop circuit 21 is reset and its Q output becomes "L", the centering operation is forcibly terminated according to the above-described operation, and the image blur prevention operation is restarted.

Embodiment 3 FIG. 4 is a diagram showing a configuration of a third embodiment of the present invention. Each SLR camera with an AF device has a CPU or a read-only memory (ROM) inside each interchangeable lens barrel in order to support various interchangeable lenses, and the main body of the camera uses communication to control weight and adjust exposure. It is often configured to receive lens information necessary for calculation such as from the lens barrel side. This embodiment shows an example in which this communication is used as a release operation prohibiting unit for such a camera.

In FIG. 4, reference numeral 31 denotes a camera body, 32 denotes an interchangeable lens barrel, and 33 denotes a release control unit.
Corresponds to the reference numeral 3 in FIG. Numeral 34 is used to calculate the distance based on the data from the distance measuring unit of the CPU (hereafter referred to as the body CPU) of the camera body and the data from the lens barrel obtained by communication, and to calculate the required lens drive amount obtained by the lens. A command is issued to the lens barrel CPU (hereinafter referred to as a lens CPU) 40 or a command for a release operation is issued. In addition, it plays a role of known and necessary control such as data display and exposure relation. 35,41
Is an interface unit responsible for communication between the body CPU 34 and the lens CPU 40.

The image blur prevention apparatus of this embodiment is built in a lens barrel, and an aperture driving unit 43 and a focus driving unit 42 are also provided in the lens barrel. Reference numeral 37 denotes an image blur prevention CPU for controlling the image blur prevention and centering operation of the image blur prevention device; 38, an interface of the image blur prevention CPU 37; 39, an image blur prevention drive unit; This corresponds to the components denoted by reference numerals 1 to 8 in the example. The interfaces 38 and 41 in the lens barrel are connected in parallel to each other, and the body-side interface 35 is connected to each other by signal terminals 36a to 36c provided inside the mount. Communication is performed by, for example, serial communication in units of 1 byte, and includes a communication synchronization clock line 36a provided from the body side, a signal line 36b from the body to the lens, a signal line 36c from the lens to the body, and a ground line (not shown). The communication system of the present example is configured using the signal lines.

In the present embodiment, transmission from the lens side to the body side is handled by the lens CPU 40. The image blur prevention CPU 37 only monitors the communication performed between the body CPU 34 and the lens CPU 40, and does not perform transmission by itself. This is to prevent serial line collisions. However, the image blur prevention CPU 37 is configured to transmit a status indicating whether or not centering is being performed to the body CPU 34 via the lens CPU 40.

Next, the release operation of the third embodiment will be described with reference to the flowcharts of FIGS.

FIG. 5 is a flowchart showing the operation of the body CPU 34 during the release sequence.

FIG. 6 is a flowchart showing the operation of the image blur prevention CPU 37.

(101): When a release switch (not shown) is pressed, the body CPU 34 enters a release sequence.

(102): First, a command (for example, 10H) indicating that the body CPU 34 has entered the release sequence is transmitted to the lens side. When the image blur prevention CPU 37 receives this command through the interface 38, the lens CP
A status (for example, 40H) indicating that the centering operation is being performed is transmitted to the body CPU 34 via U40 (204), and then a centering execution signal is sent to the image blur prevention drive unit 39 to start the centering operation (205). Then, it waits until the centering operation is completed. When the centering is completed (206), the body is set via the lens CPU 40.
A command indicating the end of centering to the CPU 34 (for example, 5
0H) (207), and waits until the release operation is started again. The image blur prevention drive unit 39 automatically starts (restarts) the image blur prevention operation when the centering operation is completed.

In (103), during this time, the body CPU 34 sets the aperture stop number determined in advance by the exposure calculation to the lens CPU 4.
Sends a command to instruct 0 (for example, 20H). lens
Upon receiving the command, the CPU 40 operates the aperture driving unit 43 to narrow down the aperture by the instructed stage number.

In (104), the quick return mirror inside the body is mirrored up through the release control unit 33. In (105), if the communication from the lens side indicates that the centering operation is still being performed, the release operation is stopped until a status indicating the end of centering is sent from the lens side. In step (106), when the status of the end of the centering is transmitted, the release operation is restarted and the shutter control is performed via the release control unit 33. At (107), an aperture opening command (for example, 30H) is used to bring down the mirror next and open the aperture that has been stopped down next.
To the lens side. Upon receiving this command, the lens CPU 40 operates the aperture driving unit 43 to open the aperture.

(At 108), the body CPU 34 next
The shutter operation is completed and the shutter is charged. Then, the release operation is completed (109).

As described above, in this embodiment, the centering operation of the image blur prevention device is given priority over the release operation,
As a result, troublesome parallel operation is prohibited, and a release operation without malfunction is ensured.

In this embodiment, the image blur prevention CPU 37 is the body C
Release operation was disabled by sending a status code indicating that centering is in progress to PU34.
The sequence on the body side is configured not to perform lens communication and release operation at the same time, but to perform serially.
If the CPU 40 has a handshake line that notifies the body CPU 34 of the completion of communication preparation (the clock line 36a for synchronization can also be used), the handshake line is used while the image blur prevention CPU 37 is centering. Communication between the lens CPU 40 and the body CPU 34 is prohibited by means of forcibly holding the camera in a communication disabled state, and release operation is prohibited during centering by keeping the body CPU 34 waiting for communication from the lens CPU 40. It is also possible to configure so that This method has an advantage that a complicated communication protocol is not used and only one handshake line is used.

In the present embodiment, the body is configured to stop the release operation after the mirror is raised, but this is because
Any time during the release operation may be used before the shutter is opened.

Embodiment 4 Embodiment 3 shown in FIG. 4 is of a type in which the release operation on the body side is stopped during centering from the image blur prevention device on the lens side, which is the same as in Embodiments 1 and 2 described above. In view of the above relationship, the configuration can be opposite to that of the third embodiment.

This example has just such a configuration, and the outline of the hardware configuration of the camera will be described with reference to FIG. This seventh
The configuration in the figure is the same as the configuration in FIG. 4 except that the lens CPU 40 and the image blur prevention CPU 37 are not connected.

The operation of the fourth embodiment will be described below with reference to the flowcharts of FIGS.

FIG. 8 is a flowchart showing the operation of the body CPU 34 during the release sequence, and FIG. 9 is a flowchart showing the operation of the image blur prevention CPU 37.

In the present embodiment, unlike the third embodiment, the status indicating that centering is in progress is not sent from the lens side to the body side, but a control start command (for example, 60H) is sent from the body side after mirror up, and the lens side image blur prevention is performed. CPU
If the centering operation is still in progress when the 37 receives this command, the centering operation is forcibly terminated. Hereinafter, the operation of this embodiment will be described in more detail.

The operation of the body CPU 34 is the same as the operation of the third embodiment from the start of the release sequence (301) to the mirror up (304). During this time, the image blur prevention CPU 37 receives the release sequence start command and starts the centering operation, and the lens CPU 40 operates the aperture driving unit 43 according to the received number of aperture steps to narrow the aperture.

The image blur prevention CPU 37 starts the centering operation (40
4) The loop is repeated until there is communication from the body CPU 34 (405) or the centering operation is completed (408).

If the centering operation is completed, the anti-shake operation is automatically started (developed) by the anti-shake driving section 39, and the anti-shake CPU 37 returns to the release operation waiting state. If there is communication from the body CPU 34 before the end of the centering operation (405), the flow proceeds to step 406 of the branch in the flowchart of FIG. In (406), when the communication from the body CPU 34 is other than the shutter control start command, the process returns to the loop for waiting for the communication from the body CPU 34 and waiting for the centering operation to end. Communication from body CPU 34 is shutter control start command (60H)
If so, the image blur prevention CPU 37 immediately terminates the centering operation (407). Then, the process returns to the next release operation waiting state. After transmitting the shutter control start command (60H) (305), the body CPU 34 performs shutter control (306). The subsequent operations in steps 307, 308, and 309 are the same as the operations in FIG.

As described above, the prohibition control of the centering operation of the image blur prevention device during the release operation is suitably realized.

The present invention is not limited to the above embodiments, and various modifications are possible.

For example, in the third and fourth embodiments, the image blur prevention unit and the lens unit for the focus drive and the aperture operation are housed in one lens, but only the image blur prevention unit is made independent,
It is easy to combine with a conventional extender and configure as an image blur prevention adapter. In this case, there is an advantage that an image blur prevention function can be added to an interchangeable lens group having no image blur prevention function.

In the third and fourth embodiments, the image blur prevention CPU 37 and the lens CPU 4 are used.
Although 0 is separate, it goes without saying that this can be replaced by one CPU.

Needless to say, the present invention can be applied not only to a single-lens reflex camera but also to a lens shutter camera. In addition, various modifications can be made to the communication means and the release sequence in the third and fourth embodiments.

The present invention is effective not only for a silver halide camera but also for a video camera or an electronic camera having a mechanical or electro-optical shutter.

[Effects of the Invention] As described above, in the present invention, the linking control for inhibiting one operation during one operation so that the centering operation and the release operation of the image blur prevention device are not performed in parallel with each other. By providing the means, it is possible to prevent, for example, a situation in which the centering operation affects the exposure of the film during the release operation, and there is an effect that a proper photographing can be always performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of a circuit configuration of a first embodiment of a camera anti-shake apparatus according to the present invention, FIG. 2 is a flowchart illustrating an operation procedure in a CPU of the anti-shake apparatus, and FIG. FIG. 4 is a block diagram showing an outline of a hardware configuration of the third embodiment, and FIGS. 5 and 6 show an operation procedure of an image blur prevention apparatus of the third embodiment. Flowchart for explanation, seventh
FIG. 11 is a block diagram showing an outline of a hardware configuration of the fourth embodiment.
8 and 9 are flowcharts for explaining the operation procedure of the image blur prevention device according to the fourth embodiment, and FIG. 10 is a diagram for explaining the outline of the configuration of the conventional image blur prevention device. DESCRIPTION OF SYMBOLS 1 ... Accelerometer, 2,3 ... Integrator 4 ... Imaging system, 5 ... Actuator 6 ... Position detecting means, 7 ... Op amp 8 ... Spring 9 ... Quick return mirror 10 ... Aperture, 11 Shutter 13 (13 ') Release control circuit 14 Gate circuit 15, Parallel I / O ₁ 16 Main CPU 17 Release switch 18 Image blur prevention CPU 19 Parallel I / O ₂ 20 One-shot circuit 21 RS flip-flop circuit 22 Reference power supply 23 Reset circuit 24 Gate circuit 26 Adder

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Kadoo 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Prefecture Tamagawa Works of Canon Inc. (56) References JP-A-1-130126 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G03B 5/00

Claims (3)

(57) [Claims] A release means for controlling a release operation;
A camera shake detecting means for detecting a camera shake state, a camera shake correcting means for driving an imaging system so as to correct the camera shake in response to an output of the camera shake detecting means, and a camera shake correction range by the camera shake correcting means. In an image blur prevention apparatus for a camera having a centering means for moving the imaging system to a center position, when one of the release means and the centering means is operated, a parallel operation of one of the other is prohibited. An image blur prevention device for a camera, comprising a linkage control means. 2. An apparatus according to claim 1, wherein said linkage control means inhibits operation of said centering means during operation of said release means. 3. The camera according to claim 1, wherein said linkage control means inhibits operation of said release means during movement of said imaging system by said centering means. Prevention device.