JPH09105997A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interchangeable lens system which can be connected in any lens unit and can perform optimum control. SOLUTION: In a video camera where the lens unit 127 including a focusing lens 105, a focusing motor 125 and a focusing driver 126 is attachably/detachably replaced from the body of a camera 128 including image pickup elements 106 to 108 and a camera signal processing circuit 112; a switch 140 controlling image output/inhibiting image output is controlled by a body microcomputer 114 so that the image output from the camera body may be inhibited until the initialization of the lens unit is finished and normal operation can be performed. Then, the lens unit can be interchanged in this video camera.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus suitable for use in a video camera or the like with interchangeable lenses.

[0002]

2. Description of the Related Art A conventional interchangeable lens system used in video equipment such as a video camera will be described with reference to FIG.

In the figure, 913 is a video camera main body, and 912 is a lens unit which can be attached to and detached from the video camera main body 911.

In a conventional variable-magnification lens unit, a variable-magnification lens 902a and a correction lens 902b are mechanically connected by a cam, and when the variable-magnification operation is performed manually or electrically, the variable-magnification lens 902a and the correction lens 902b. Move together.

The zoom lens 902a and the correction lens 902b are collectively referred to as a zoom lens. In such a lens system, the front lens 901 is a focus lens, and the focus is adjusted by moving in the optical axis direction.

The light passing through these lens groups is imaged on the image pickup surface of the image pickup device 903, photoelectrically converted into an electric signal, and outputted as a video signal.

This video signal is sampled and held by the CDS / AGC 503 and then amplified to a predetermined level.
Converted to digital video data by the / D converter 904,
The signal is input to the process circuit of the camera in the subsequent stage and converted into a standard television signal, and at the same time, the AF signal processing circuit 90.
6 is input.

The AF signal processing circuit 905 extracts the high frequency component from the video signal and uses the microcomputer 90 as an AF evaluation value.
Taken in 7.

The microcomputer 907 determines the motor driving direction so that the focusing speed according to the degree of focus and the AF evaluation value increase, and the speed and direction of the focus motor are determined by the focus motor driver 9 in the lens unit 912.
Then, the focus lens 901 is driven via the focus motor 910.

The state of the zoom switch 908 is read by the microcomputer 907, and the microcomputer 907 determines the zoom lens 902 according to the operation state of the zoom switch 908.
a, 902b drive directions and drive speeds are determined and sent to the zoom motor driver 911 in the lens unit 912,
The zoom lenses 902 a, 9 a via the zoom motor 912
Drive 02b.

The camera body 913 is a lens unit 91.
2 can be separated, and the shooting range is expanded by connecting another lens unit.

[0012]

By the way, in recent consumer integrated cameras, the correction lens and the variable power lens are mechanically coupled by a cam in order to make the size of the camera and the photographing up to the front surface of the lens possible. Stop, and the movement locus of the correction lens for correcting changes in the focal plane position due to movement of the zoom lens is stored in the microcomputer in advance as lens cam data, and during zoom operation the correction lens is adjusted according to the lens cam data. Inner focus type lenses, which are driven and whose focus is also adjusted by the correction lens, are becoming mainstream.

The inner focus type lens generally recognizes the positions of the correction lens and the variable power lens by a microcomputer and controls based on the recognized absolute position. Further, the movement locus of the correction lens during the zooming operation is also obtained by processing the lens cam data based on the absolute position.

By the way, in the conventional front lens focus lens type interchangeable lens system, even if the power circuit of the lens is turned on and off immediately in synchronization with the turning on and off of the power supplied from the main body, no problem occurs. There wasn't.

However, in such an inner focus type lens system, an initialization operation is required when the power is turned on and a post-processing operation is required when the power is turned off in order to manage the correction lens and the variable magnification lens by the microcomputer. The operation member placed on the lens immediately when the power supply of the main body is turned on, the image is displayed immediately when the power supply of the main body is turned on, If is enabled, shooting will start before the lens initialization is completed and a blurred image or poor quality image will be recorded, or the power will be shut off before the lens post-processing is completed. When the power is turned on, the control is confused, and it takes a long time to return to the normal state.

Therefore, the object of the present invention is to solve the above-mentioned problems, and it is possible to connect any lens unit such as an inner focus type lens unit in addition to the conventional front focus type lens unit, and An object of the present invention is to provide an interchangeable lens system that can be controlled without causing the above inconvenience.

[0017]

In order to solve the above problems, according to the invention described in claim 1 of the present application, a focus lens (corresponding to the focus lens 105 in the embodiment) and a control means for the focus lens. The lens unit (127) including (corresponding to the lens microcomputer 116 in the embodiment) is used as an image pickup unit (the image pickup device 1 in the embodiment).
06 to 108, which corresponds to the camera signal processing circuit 112)
In the image pickup apparatus that can be detached from the camera body (128) and replaced, the prohibiting means (in the embodiment, the main body microcomputer 114, in the embodiment, a body microcomputer 114, which prohibits image output from the camera body until initialization of the lens unit is completed and normal operation becomes possible. Switch 1
(Corresponding to 40), the lens unit is replaceable.

According to the invention of claim 2 in the present application, a variable power lens (102) for performing a variable power operation, and a correction lens for correcting the focus in order to maintain the in-focus state by the variable power operation (implementation In the example, it corresponds to the focus lens 105), and a lens unit including a control means (corresponding to the lens microcomputer 116 in the embodiment) for the variable power lens and the correction lens is used as an image pickup means (the image pickup elements 106 to 1 in the embodiment).
08, which corresponds to the camera signal processing circuit 112) and which can be normally operated after completion of initialization of either or both of the correction lens and the variable power lens in an image pickup device detachable from the camera body (128). Prohibition means (provisional microcomputer 1
(Corresponding to 14), the lens unit is replaceable.

According to the third aspect of the present invention, the lens unit including the focus lens and the control means for the focus lens can be attached to and detached from the camera body including the image pickup means, and the lens can be detached from the camera body. In an imaging apparatus having a power supply unit for supplying power to a unit, the power supply unit supplies a power cutoff request signal (lens on / off request signal) from the camera body to the lens unit to prepare for power cutoff of the lens unit. A lens unit replaceable imaging device that shuts off power in response to a power shutoff permission signal (lens off permission signal) returned from the lens unit to the camera unit upon completion.

According to the fourth aspect of the present invention, the focus lens, the control means for the focus lens (lens microcomputer 116), and the focus adjustment operation means (corresponding to the power focus switch 137).
In an image pickup apparatus in which a lens unit including a lens unit is detachably attached to a camera body including an image pickup unit, a prohibition unit that prohibits the operation unit of the lens unit when the image pickup unit output of the camera body is not displayed. An image pickup device having a lens unit replaceable (having a body microcomputer 114) is characterized.

According to the invention of claim 5 in the present application, a variable power lens (102) for performing a variable power operation and a correction lens (105 for correcting the focus in order to maintain the in-focus state by the variable power operation. ), A control unit for the variable power lens and the correction lens (corresponding to the lens microcomputer 116 in the embodiment), and a variable power or focus adjustment operation unit in a camera body including an imaging unit. On the other hand, in the detachable image pickup device, a prohibiting means (corresponding to the main body microcomputer 114 in the embodiment) for prohibiting the operating means of the lens unit is provided in a state where the image pickup means output of the camera body is not displayed. It is characterized by an image pickup device having a replaceable lens unit.

According to a sixth aspect of the present invention, a lens unit which is attachable to and detachable from a camera body including an image pickup means and which includes a lens and a control means for the lens (corresponding to the lens microcomputer 116 in the embodiment). Therefore, a prohibition unit (in the embodiment, the lens microcomputer 116) that outputs a prohibition signal (image output permission signal 143) for prohibiting image output to the camera body until initialization of the lens unit is completed and normal operation becomes possible. Corresponding to the lens unit).

According to a seventh aspect of the present invention, a lens which is attachable to and detachable from the camera body including the image pickup means and includes a focus lens and a control means for the focus lens (corresponding to the lens microcomputer 116 in the embodiment). The unit is a unit that drives the focus lens to a predetermined position and terminates the drive to the predetermined position in response to a power cutoff command (lens on / off request signal) supplied from the camera body side. Up to the camera body side, a prohibition signal (lens-off permission signal 144 in the embodiment) for prohibiting interruption of power supply to the lens unit is output, and in response to completion of driving to the predetermined position, A means for canceling the prohibition signal (in the embodiment, the lens microcomputer 1
16) The lens unit characterized by having.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example in which the present invention is applied to an interchangeable lens type video camera.

The light from the subject is a fixed first lens group 101, a second lens group (hereinafter referred to as a variable magnification lens) 102 for varying the magnification, a diaphragm 103, and a fixed third lens. The group 104 passes through a fourth lens group (hereinafter referred to as a focus lens) 105 having both a focus adjustment function and a compensator function for correcting the movement of the focal plane due to zooming, and a red component and a green component in the three primary colors. , Blue components are imaged on the image pickup surfaces of the image pickup device 106 such as CCD, the image pickup device 107, and the image pickup device 108, respectively.

The image of each color component formed on the image pickup surface of each image pickup device is photoelectrically converted and the amplifier 10 is used.
Each of the signals is amplified to an optimum level by 8, 109 and 110, input to the camera signal processing circuit 112, and converted into a standard television signal.

The video signal output from the camera signal processing circuit 112 is supplied to a video recorder (not shown) and an electronic viewfinder (not shown) by meeting the switch 140, and recording and monitoring are possible.

By switching the switch 140, it is possible to reproduce the image information recorded immediately before by the video recorder and check the recording state (so-called rec review).

The brightness signal generated in the camera signal processing circuit 112 is input to the AF signal processing circuit 113. Although not shown, information about the luminance signal level is sent from the camera signal processing circuit 112 to the lens macon 116 in the lens unit, which controls the opening and closing of the diaphragm 103 to keep the luminance signal level constant. Is done. Further, the aperture amount of the diaphragm is detected by the encoder 129 and used as AF depth control for AF control or manual aperture control.

In the AF signal processing circuit 113, a high frequency component in the brightness signal which changes according to the focus state is detected as an AF evaluation value, and the AF evaluation value is 128 in the camera body.
It is read by the data reading program 115 in the main body microcomputer 114 therein and transferred to the lens microcomputer 116.

When the information of the power switch 138 of the camera is read into the main microcomputer 114 and the power switch 138 is turned on, the main microcomputer 114 switches the switch 1
By controlling 39, power is supplied to the lens unit side from a battery (not shown) arranged in the camera body.

From the main body microcomputer 114 to the lens unit side, in addition to the AF evaluation value described above, a lens on / off request signal 142 for turning on / off the control on the lens unit side, and an operation key on the lens unit side. A lens key prohibition signal 145 or the like for prohibiting the operation is transmitted.

From the lens unit side, an image output permission signal 143 for supplying an image signal output from the camera signal processing circuit 112 to an electronic viewfinder or a video recorder to permit image output, and turning off the power source on the lens side. A lens off permission signal 144 indicating that the lens unit may be turned on is received, and control is performed according to the operating state of the lens unit.

In the lens microcomputer 116, an AF switch (AF for ON, manual for OFF) 131, a zoom switch for operating the zoom lens to the tele side (T) or the wide side (W) for zooming operation. 136,
When the AF switch is off and in the manual focus mode, the state of the power focus switch 137 for operating the focus lens in the close-up direction or the infinite direction is read, and control according to each operation state is performed. .

That is, when the AF switch 131 is off and the zoom switch 136 is pressed, the lens microcomputer 116 causes the computer zoom program 11 to operate.
9 sends a signal to the zoom motor driver 122 to drive the variable power lens in the direction in which the variable power lens 1 is operated in the tele or wide direction.
The lens cam data (see FIG. 4) stored in advance inside the lens microcomputer 116 in order to correct the focal plane position associated with the movement of the variable magnification lens at the same time as driving 02.
Based on 0, the focus motor 125 is driven via the focus motor driver 126, and the focus lens 105 is drive-controlled.

The AF switch 131 is turned on (AF mode)
And when the zoom switch 136 is operated, the displacement of the focal plane due to the zooming operation is corrected, and
Since it is necessary to correct the occurrence of blurring due to relative movement with the subject and keep the in-focus state, the computer zoom program 119 only needs to know the information of the lens cam data 120 stored in advance inside the lens microcomputer 116. Instead, the zooming operation is performed while also referring to the AF evaluation value signal sent from the main body microcomputer 114 and maintaining the position where the AF evaluation value is maximum.

When the AF switch 131 is on and the zoom switch 136 is not pressed, the AF program 117 signals the focus motor driver 126 to maximize the AF evaluation value signal sent from the main body microcomputer 114. The focus lens 105 is driven via the focus motor 125 to perform the automatic focus adjustment operation.

Further, the AF switch 131 is off (manual focus mode), and the zoom switch 13
When 6 is not pressed, the focus motor driver 1 is moved in the direction in which the power focus switch (manual focus switch) 137 is pressed infinitely or infinitely.
The focus lens 105 is driven via the focus motor 125 by sending a signal to the camera 26 to perform manual focus adjustment.

Next, the sequence from power-on to power-off of the camera will be described with reference to FIG. 1 and FIG.

When the power switch 138 of the camera is turned on at time t0, the main body microcomputer 114 is powered on,
At time t1, the power switch 139 for supplying power to the lens unit is turned on, and at the same time, the lens on / off request signal 142 is changed from low level to high level.

In response to this, the lens microcomputer 116 initializes the lens unit (lens reset), and at the time t2, at the same time when the initialization is completed, the image output permission signal 14
Change 3 from low to high. As a result, the fact that the initialization of the lens unit is completed is transmitted to the camera side.

Upon receiving the image output permission signal 143, the main body microcomputer 114 on the camera side changes the lens key prohibition signal 145 from the low level to the high level (the operation key on the lens unit side becomes effective), and at the same time, the camera signal is transmitted. Processing circuit 1
The video signal output from 12 is output to an electronic viewfinder or a video recorder.

From the time t0, the lens microcomputer 116
Until t2, the AF switch 131, the manual focus switch 137, and the zoom switch 136 were forbidden (lens key prohibition signal 145 was low) so that they would not be effective even if they were pressed, but the lens key prohibition signal 145 became high. In response, the AF switch 131, the manual focus switch 137, and the zoom switch 136 are activated.

At time t3, the REC review signal 147 becomes high level, the switch 140 is switched to the video recorder side, the video signal from the reproducing device recorded immediately before is passed to the finder 148, and at the same time the lens key is prohibited. The signal 145 is set to low level.

As a result, the lens microcomputer 116
AF switch 131 and manual focus switch 1
Even if the 36 or the zoom switch 137 is operated, it is prohibited so as not to be effective. That is, during reproduction of a REC review or the like, driving of each lens on the lens unit side is prohibited and control is performed so that the state at that time is not changed.

At time t4, the REC review signal 147 becomes low level, and at the same time, the switch 140 changes the video signal from the camera signal processing circuit 112 to the electronic viewfinder 1.
Then, the lens key prohibit signal 145 becomes high level, and the lens microcomputer 116
AF switch 131, manual focus switch 1
37 and the zoom switch 137 are enabled.

When the camera power switch 138 is turned off, at time t5, the main body microcomputer 114 sets the lens on / off request signal 142 to the low level and also sets the lens key prohibition signal 145 to the low level.

In response to these, the lens microcomputer 116 starts preparations for turning off the power in the lens unit, for example, moves the focus lens 105 and the zoom lens 102 to predetermined positions, and at the same time sets the lens image output permission signal to a low level to make a camera image. Does not display images, and AF switch 1
31, the manual focus switch 137, and the zoom switch 136 are invalidated.

That is, when the power is turned off, the movable part such as each lens in the lens unit is moved to a predetermined position before the power is turned off, and an image of poor quality during the operation is displayed electronically. It is possible to prevent the image from being output to a finder or a video recorder.

The lens microcomputer 116 sets the lens-off permission signal 144 to the high level at the time t6 when the power-off preparation is completed. The lens microcomputer 114 switches the switch 13 in response to the lens off permission signal 114 becoming high level.
By turning off 9, the power supply to the lens unit side is cut off, and then the power supply to the camera side is cut off.

In this embodiment, the AF evaluation value 141, the lens on / off request signal 142, the image output permission signal 143, the lens off signal 144, the lens key prohibition signal 145, etc. are connected to the camera body 128 and the lens by a dedicated signal line. Unit 127
However, it is also possible to perform serial or parallel bidirectional data communication between the main body microcomputer 116 and the lens microcomputer 116 and put the respective contents at predetermined positions of the data communication.

Next, referring to FIG. 3, when the zooming operation is not performed in the lens microcomputer in the lens unit,
The algorithm of the automatic focus adjustment operation of the AF program 117 will be described.

The algorithm of the automatic focusing operation performed by the AF program 117 when the zoom operation is not performed in the lens microcomputer 116 in the lens unit 127 will be described with reference to FIG.

When the processing is started, the AF operation is first activated in the processing of step 1, and then the processing shifts to step 2 to compare the level of the AF evaluation value signal with a predetermined threshold value to make a large blur. The speed control is performed by determining whether the focus is near the focus or how far from the focus.

At this time, the level of the AF evaluation value signal is low,
At the foot of the mountain, that is, when it is expected to be a large blur, the focus lens is controlled to climb in the direction in which the AF evaluation value signal increases, and the level of the AF evaluation value signal increases as it approaches the top of the mountain. However, when it is near the in-focus point, the process proceeds to step 3, and the apex of the mountain is determined based on the change amount of the absolute value of the AF evaluation value and the like. If it is determined that the point is at a high level, the focus lens is stopped in step 4 and step 5
The process goes to the restart standby.

In the restart waiting state, when it is detected that the level of the AF evaluation value is lower than the peak value when the in-focus point is detected by a predetermined level or more, the process shifts to step 6 and the focus lens is restarted. To start. By repeatedly performing the above processing, the AF operation can be always performed.

Next, the relationship between the movements of the variable power lens 102 and the focus lens 105 when performing the variable power operation and how to refer to the AF evaluation value signal during the variable power operation from wide to tele will be described. .

In the lens system configured as shown in FIG. 1, since the focus lens 105 has both a compensator function and a focus adjustment function, the image pickup elements 106, 107 and 108 are focused even if the focal lengths are the same. The position of the focus lens 105 for this purpose varies depending on the subject distance.

When the subject distance is changed at each focal length, the position of the focus lens 105 for focusing on the image pickup surface is continuously plotted, as shown in FIG. During the zooming operation, the trajectory shown in FIG. 4 is selected according to the subject distance, and the focus lens 1 is moved according to the trajectory.
By moving 05, zooming without blur becomes possible.

In the front lens focus type lens system, an independent compensator lens is provided for the variable power lens, and the variable power lens and the compensator lens are connected by a mechanical cam ring.

Therefore, for example, when a knob for manual zooming is provided on this cam ring and the focal length is manually changed, no matter how fast the knob is moved, the cam ring will follow this and rotate to change the magnification. Since the lens and the competing lens move along the cam groove of the cam ring, if the focus lens is in focus, the above operation does not cause blurring.

However, in the control of the inner focus type lens system having the above-mentioned characteristics, when the zooming operation is performed while keeping the focus, the locus information of FIG. It is necessary to store it as 120, read the trajectory information according to the position or the moving speed of the variable magnification lens 102, and move the focus lens based on the information.

FIG. 5 is a diagram for explaining an example of the proposed trajectory following method. In the figure, Z0, Z
1, Z2, ... Z6 indicate the zoom lens positions, and a0, a
1, a2, ... A6 and b0, b1, b2, ... B6 are representative loci stored in the lens microcomputer 116, respectively.

Further, p0, p1, p2, ... P6 are loci calculated based on the above two loci. The formula for calculating this locus is shown below.

P (n + 1) = | p (n) -a (n) | / | b (n) -a (n) | * | b (n + 1) -a (n + 1) | + a (n + 1) (1) According to the equation (1), for example, in FIG. 5, when the focus lens is at p0, the ratio at which p0 internally divides the line segment b0-a0 is obtained, and according to this ratio, The point internally dividing the line segment b1-a1 is designated as p1. From the position difference between p1 and p0 and the time required for the variable power lens to move from Z0 to Z1, the moving speed of the focus lens for keeping the focus can be known.

Next, the stop position of the variable power lens is not limited to only the boundary where the stored representative trajectory data is owned, and a case in which any position can be set will be described.

FIG. 6 is a diagram for explaining the interpolation method in the position of the variable power lens, that is, the moving direction of the variable power lens. A part of FIG. 5 is extracted and the position of the variable power lens 102 is set arbitrarily. Is.

In FIG. 5, the vertical axis represents the focal lens position and the horizontal axis represents the variable lens position. The representative locus position (focus lens position relative to the variable lens position) stored in the lens control microcomputer is changed. Double lens position Z0,
For Z1, ... Zk-1, Zk ... Zn, the focus lens position at that time is a0, a1, ... ak-1, ak ... an b0, b1, for each object distance. ... bk-1, bk ... bn.

When the zoom lens position is not on the zoom boundary and the focus lens position is Px, when ax and bx are calculated, ax = ak- (Zk-Zx) * (ak-ak-1) ) / (Zk-Zk-1) (2) bx = bk- (Zk-Zx) * (bk-bk-1) / (Zk-Zk-1) (3).

That is, the current zoom lens position and two zoom boundary positions sandwiching the zoom lens position (for example, Zk and Zk- in FIG. 6).
According to the internal division ratio obtained from 1) and 4), the one of the four stored representative locus data (ak, ak-1, bk, bk-1 in FIG. 6) with the same subject distance is By dividing internally, ax and bx can be obtained.

Then, according to the internal division ratio obtained from ax, Px, bx, four representative data stored (in FIG. 6, ak, a
Of k-1, bk, bk-1), pk, pk-1 can be obtained by internally dividing those having the same focal length with the internal division ratio as shown in equation (1).

During zooming from wide to tele, the focus difference is maintained from the position difference between the follow-up focus position pk and the current focus position px and the time required for the zoom lens to move from Zx to Zk. You can see the moving speed of the focus lens.

Further, when zooming from tele to wide, the focus is determined from the position difference between the follow-up focus position pk-1 and the current focus position Px and the time required for the zoom lens to move from Zx to Zk-1. The moving speed of the focus lens for keeping A trajectory following method as described above has been proposed.

In order to perform the above-mentioned trajectory tracking, it is necessary to recognize the positions of the focus lens and the variable power lens as absolute positions.

Therefore, when the power is turned on, the focus lens and the variable power lens are brought into contact with a predetermined position (reset position), that is, the infinite end or the wide end so that the position coincides with P (0,0) in FIG. In addition, the lens microcomputer recognizes the absolute position.

This is the initialization operation of the focus lens and the variable power lens. Further, in order to speed up the initialization operation, the positions of the focus lens and the variable power lens are stored in the microcomputer as post-processing when the power is shut off, and moved to the vicinity of the reset position. And when the power is turned on again,
After performing the initialization operation, by moving again to the positions of the focus lens and the variable magnification lens stored in the lens microcomputer, it is possible to start shooting in the same state as before power-off.

By the way, when the AF switch 131 is on, it is necessary to follow the locus while maintaining focus.

When the variable power lens moves from the telephoto to the wide direction, as is clear from FIG. 4, the scattered locus is in the direction of converging, so the focus can be maintained even by the above-mentioned locus tracking method.

However, in the wide-to-tele direction,
Since it is not known which trajectory the focus lens at the convergence point should follow, the similar trajectory following method cannot maintain the focus.

FIG. 7 is a diagram for explaining an example of a trajectory following method proposed for the above problem. In both (a) and (b) of the figure, the horizontal axis indicates the position of the variable power lens, and the vertical axis indicates the level of the high frequency component (sharpness signal) of the video signal which is the AF evaluation signal. And (b) shows the position of the focus lens.

In FIG. 7, it is assumed that the focus cam locus at the time of zooming a certain object is 604. Here, the focusing cam locus following speed on the wide side from the zoom position 606 (Z14) is positive (moved in the direction close to the focus lens), and the focusing cam locus following speed moving on the tele side from 606 to the infinite direction is negative. .

When the focus lens follows the cam locus 604 while maintaining the focus, the magnitude of the sharpness signal becomes 601. In general, it is known that the sharpness signal level has a substantially constant value in zooming while maintaining focus.

In FIG. 7B, the focus lens moving speed for tracing the focus cam locus 604 during zooming is Vf0. When the actual moving speed of the focus lens is Vf and zooming is performed with Vf0 tracing the cam locus 604 being increased or decreased, the locus is 60.
It becomes a zigzag locus like 5. At this time, the sharpness signal level changes to produce peaks and valleys as indicated by 602. Here, at the position where the trajectories 604 and 605 intersect, 60
3 becomes the maximum (Z0, Z1, ... Z16 even points), and the moving direction vector of 605 switches Z0,
At the odd points of Z1, ... Z16, the level of 603 becomes the minimum. 602 is the minimum value of 603, but conversely 602
If the level TH1 is set and the moving direction vector of the locus 605 is switched every time the size of 603 becomes equal to TH1, the moving direction of the focus lens after switching can be set to a direction closer to the focus locus 604. That is, each time the image blurs by the difference between the sharpness signal levels 601 and 602 (TH1), the moving direction and speed of the focus lens are controlled so as to reduce the blurring, whereby zooming with the blur amount suppressed can be performed.

By using the above-described method, in the wide-to-tele zooming in which the cam locus as shown in FIG. 4 diverges from the convergence, even if the focusing speed Vf0 is not known, the explanation is given with reference to FIG. For the follow-up speed (calculated using p (n + 1) obtained from the equation (1)), the switching operation is repeated as indicated by 605 while controlling the focus lens moving speed Vf (change in sharpness signal level). According to this), the locus can be selected such that the sharpness signal level does not drop below 602 (TH1), that is, the blurring of a certain amount or more does not occur. Here, the moving speed Vf of the focus lens is Vf = Vf0 + Vf + (4) Vf = Vf0 + Vf- (5), where Vf + is the correction speed in the positive direction and Vf- is the correction speed in the negative direction. The correction velocities Vf + and Vf- at this time are determined by the above-mentioned zooming method so that deviations when selecting the following trajectory do not occur, and the internal angles of the two direction vectors of Vf obtained by the equations (4) and (5) are determined. Is 2 due to the direction vector of Vf0
It is decided to be divided equally.

By changing the magnitude of the correction amount by the correction speed according to the subject, the focal length, and the depth of field, the increase / decrease cycle of the sharpness signal is changed to improve the selection accuracy of the tracking locus. Another method is also proposed.

[0086]

As described above, according to the invention described in claim 1 or 2 of the present application, the prohibition of prohibiting the image output from the camera body until the initialization of the lens unit is completed and the normal operation becomes possible. By including the means, it is effective to prevent unsightly movement such as the initialization operation of the lens from being output as a camera image.

According to the third aspect of the present invention, a power-off request signal is supplied from the camera body to the lens unit, and when the lens unit is ready for power-off, the lens unit returns the signal to the camera unit. By having the power supply means for turning off the power supply in response to the power supply cutoff permission signal, it is possible to prevent the power supply from being cut off until the post-processing of the lens unit is completed and the power supply can be turned off.

Further, according to the invention of claim 4 or 5 in the present application, by having the prohibition means for prohibiting the operation means of the lens unit in a state where the image pickup means output of the camera body is not output, There is an effect that it is possible to prevent the operating member of the lens from being inadvertently operated while the image is not displayed. Therefore, not only the conventional front focus type lens unit but also an inner focus type lens unit can be connected, and it is possible to provide an interchangeable lens system to which any type of lens system can be connected.

Further, according to the invention of claim 6 in the present application, since the camera body is prohibited from outputting the image until the initialization of the lens unit is completed and the normal operation becomes possible, the initialization operation of the lens is performed. This has the effect of preventing unsightly movements such as being displayed as a camera image.

According to the invention of claim 7 in the present application, the focus lens is driven to a predetermined position in accordance with a power-off command from the camera body side, and the camera body is driven until the driving is completed. Since a prohibition signal that prohibits the cutoff of the power supply to the lens unit is output to the side, the lens stop position can be set accurately when the power is cut off, and the next time the power is turned on, normal operation will be performed quickly. Can be transferred.

According to the invention described in each of the claims of the present application, not only the front lens focus type but also any type of lens unit such as the inner focus type lens unit can be connected, and each lens unit can be connected. It is possible to realize an interchangeable lens system capable of optimally controlling the lens.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration when the present invention is applied to an interchangeable lens type video camera.

FIG. 2 is a diagram showing a power-on / off sequence in the video camera of FIG.

3 is a flow chart for explaining an AF operation in the video camera of FIG.

FIG. 4 is a characteristic diagram showing, for each object distance, a focus locus of the focus lens that changes according to the zoom lens position in the inner focus type lens control.

FIG. 5 is a diagram for explaining a calculation for interpolating an unstored cam locus from information on a plurality of cam loci stored in lens cam data.

FIG. 6 is a diagram for explaining a calculation for interpolating an unstored cam locus from information on a plurality of cam loci stored in lens cam data.

FIG. 7 is a diagram for explaining an algorithm for causing a focus lens to follow a cam locus.

FIG. 8 is a block diagram showing an example of a conventional interchangeable lens system.

[Explanation of symbols]

 102 variable magnification lens 105 focus lens 106 image sensor 107 image sensor 108 image sensor 112 camera signal processing circuit 113 AF signal processing circuit 114 (camera) main body microcomputer 116 lens microcomputer 117 AF program 120 lens cam data 121 zoom motor 122 zoom motor driver 125 Focus motor 126 Motor driver

Claims (7)

[Claims] 1. An image pickup apparatus in which a lens unit including a focus lens and a control unit for the focus lens can be detached from a camera body including an image pickup unit and replaced, until initialization of the lens unit is completed and normal operation becomes possible. An image pickup apparatus in which a lens unit is replaceable, which has a prohibition unit that prohibits image output from the camera body. 2. A lens unit including a variable power lens that performs a variable power operation, a correction lens that corrects a focus for maintaining a focus state in the variable power operation, and a control unit for the variable power lens and the correction lens. In an image pickup device that is detachable from a camera body including an image pickup means, prohibits image output from the camera body until initialization of either or both of the correction lens and the variable magnification lens is completed and normal operation becomes possible. An image pickup apparatus having a replaceable lens unit, which has a prohibition unit. 3. A lens unit including a focus lens and control means for the focus lens is attachable to and detachable from a camera body including the image pickup means, and has an electric power supply means for supplying power from the camera body to the lens unit. In the above, the power supply means supplies a power cutoff request signal from the camera body to the lens unit, and power is supplied in response to a power cutoff permission signal returned from the lens unit to the camera unit upon completion of power cutoff of the lens unit. Image pickup device with interchangeable lens unit 4. An imaging device in which a lens unit including a focus lens, control means for the focus lens, and operation means for focus adjustment can be attached to and detached from a camera body including an image pickup means. An image pickup apparatus in which the lens unit can be replaced, which has a prohibition unit that prohibits the operation unit of the lens unit when no image is displayed. 5. A variable power lens for performing a variable power operation, a correction lens for correcting a focus for maintaining a focus state in the variable power operation, and a control means for the variable power lens and the correction lens.
In an imaging device in which a lens unit including an operating unit for zooming or focus adjustment is attachable to and detachable from a camera body including an image capturing unit, in a state where the image capturing unit output of the camera body is not displayed, An image pickup apparatus in which a lens unit can be replaced, which has a prohibition unit that prohibits the operation unit of the lens unit. 6. A lens unit detachably mountable to a camera body including an image pickup means, the lens unit including a lens and a control means for the lens, wherein the camera body is maintained until initialization of the lens unit is completed and normal operation is possible. A lens unit comprising a prohibition means for outputting a prohibition signal for prohibiting image output. 7. A lens unit detachably mountable to a camera body including an image pickup means, the lens unit including a focus lens and a control means for the focus lens, wherein the focus unit responds to a power-off command supplied from the camera body side. While driving the lens to a predetermined position, until the driving to the predetermined position is completed, a prohibition signal for prohibiting the cutoff of power supply to the lens unit is output to the camera body side, and the lens is moved to the predetermined position. A lens unit comprising means for releasing the prohibition signal in response to the end of driving.