Abstract:
A control apparatus for an optical device including a lens system having a moving lens and a camera to which the lens system is attached, includes a first control signal output unit including a first operation member and outputting a first control signal to control a movement of the moving lens in accordance with an operation of the first operation member, where the first control signal output unit is electrically connected to the lens system, and a second control signal output unit including a second operation member and outputting a second control signal to control a movement of the moving lens in accordance with an operation of the second operation member, where the second control signal output unit is electrically connected to the camera, and the second control signal is output to the lens system through the camera. The apparatus further includes a first detection unit that detects the first control signal, a second detection unit that detects the second control signal, a selection unit that selects one of the first and second control signals on the basis of output signals from the first and second detection units, and a driving unit that drives the moving lens on the basis of one of the first and second control signals selected by the selection unit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image pickup apparatus and a phototaking lens used therein and, more particularly, to an image pickup apparatus such as a TV camera which is suitably used to attain focusing of the phototaking lens by selecting a control signal (operation signal) from a focus demand attached to the phototaking lens or a camera control unit (CCU) mounted on the camera body. 
     2. Related Background Art 
     The conventional methods of manual focusing (to be referred to as the “focus function” hereinafter) of a phototaking lens include the method of manually operating the focus ring (which is directly performed by the hand of a cameraman) and the method of electrically operating the focus mechanism of the phototaking lens by using an actuator such as a motor. When the focus mechanism of the phototaking lens is to be electrically operated in a TV camera or the like, focusing is directly performed from the phototaking lens side, or focusing is performed on the CCU (Camera Control Unit) mounted in a relay station electrically connected to the phototaking lens. 
     FIG. 8 is a block diagram for explaining focusing to be performed in a conventional TV camera. 
     Referring to FIG. 8, focusing of a phototaking lens  901  is performed from a demand  903  connected to the phototaking lens  901  or from a control knob  905  on a CCU  904  at the relay station  902  side. An R/L switch  906  on the CCU  904  is operated to choose between using the demand  903  of the phototaking lens  901  and using the control knob  905  of the CCU  904 . “R” of the R/L switch  906  represents remote control, i.e., an operation from the control knob  905  of the CCU  904 . “L” of the R/L switch  906  represents local control, i.e., an operation from the demand  903  connected to the phototaking lens  901 . 
     In the image pickup apparatus having a conventional focus mechanism, the R/L switch on the CCU is operated to switch the focusing operation between the demand operation of the phototaking lens and the CCU. This arrangement poses the following problem. 
     Assume that a TV crew is shooting for a relay broadcast of a golf tournament, while the phototaking lens is set near the green of the 18 th  hole, and the CCU is mounted in a relay car near the club house. Normally, the cameraman who operates the phototaking lens performs focusing by operating the demand connected to the phototaking lens while watching the TV monitor. In this case, focusing is performed when the R/L switch of the CCU is set at “L”. In some cases, however, an operator performs fine focusing by using the CCU in the relay car while watching the monitor. In this case, focusing is performed after the R/L switch of the CCU is switched from “L” to “R”. If, however, the operator forgets to switch the R/L switch back from “R” to “L” after focusing with the CCU is complete, the cameraman cannot perform focusing at the phototaking lens side, which may pose a problem in shooting a TV program. In practice, the cameraman and the staff in the relay car exchange information through a network, such as an intercom, and hence serious trouble is unlikely to occur. This is, nevertheless, a drawback in terms of the utility of the photographing equipment system. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an image pickup apparatus suited for a TV camera, in particular, and a phototaking lens used therein, which can smoothly and reliably perform focusing and zooming of the phototaking lens by using a detection means for detecting the operation states of the demand (focus demand) of the phototaking lens and the control knob of a CCU and automatically switching focusing and zooming control on the basis of a signal from the detection means, without using an R/L switch in the CCU of the relay station, as has been used in the prior art. 
     According to the present invention, there is provided an image pickup apparatus for driving a moving lens in accordance with first and second command signals, comprising first detection means for detecting the first command signal, second detection means for detecting the second command signal, selection means for selecting one of the first and second command signals on the basis of output signals from the first and second detection means, and driving means for driving the moving lens on the basis of the command signal selected by the selection means. 
     The selection means includes a plurality of algorithms. The apparatus includes a setting means for selectively setting these algorithms. The selection means selects a command signal in accordance with the algorithm set by the setting means. 
     The above and other objects, features, and advantages of the present invention will be apparent from the following detailed description in conjunction with the accompanying drawings and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing the overall arrangement of an image pickup apparatus according to the present invention; 
     FIGS. 2A and 2B are block diagrams showing the detailed arrangement of the main part of the present invention; 
     FIG. 3 is a flow chart showing the overall operation of the present invention; 
     FIG. 4 is a flow chart showing a first press priority procedure in the present invention; 
     FIG. 5 is a flow chart showing a last press priority procedure in the present invention; 
     FIG. 6 is a flow chart showing a remote priority procedure in the present invention; 
     FIG. 7 is a flow chart showing a local priority procedure in the present invention; and 
     FIG. 8 is a block diagram showing the main part of a conventional image pickup apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a block diagram showing the main part of the first embodiment of the present invention. FIGS. 2A and 2B are enlarged views for explaining a part of the arrangement in FIG.  1 . FIGS. 3 to  7  are flow charts showing the operations of the first embodiment of the present invention. 
     Referring to FIGS. 1 and 2A, a CCU control signal  101  from a camera control unit (CCU)  103  is input to a decision unit (detection means)  106  of a phototaking lens  112  through a camera (camera body)  105 , and is also input to a terminal a of a switching unit (selection means)  108 . Similarly, a demand control signal  102  output from a demand (focus demand)  104  (connected to the phototaking lens  112 ) on the basis of an operation performed by a cameraman is input to the decision unit  106  of the phototaking lens  112 , and is also input to a terminal b of the switching unit  108 . An output from a priority changeover switch (algorithm changeover means)  107  is input to the decision unit  106 , and is further output from the decision unit  106  to the switching unit  108 . only the signal, of the CCU control signal  101  and the demand control signal  102  input to the switching unit  108 , which is selected by the decision unit  106  is output from the switching unit  108  to a driving unit  109  for driving a focus motor  110 . The focus motor  110  finally drives a focus mechanism unit  111  of the phototaking lens  112  on the basis of the signal from the driving unit  109 . 
     A display means  113  displays the type of algorithm designated by the priority changeover switch  107 . In this case, the driving unit  109 , the focus motor  110 , and the focus mechanism unit  111  constitute one element of the focus driving mechanism. 
     The decision unit (detection means)  106  has a plurality of algorithms for selecting the CCU control signal  101  or the demand control signal  102 . For example, the above-mentioned selection means has an algorithm for preferentially selecting a control signal from either the focus demand or the CCU when control signals are simultaneously output from both the focus demand and the CCU. 
     The priority changeover switch (algorithm changeover means)  107  designates one of the algorithms set in the decision unit  106 . The decision unit (detection means)  106  includes a first detection means ( 203 ,  205 ) for detecting the demand control signal  102  from the focus demand  104  and a second detection means ( 204 ,  205 ) for detecting the CCU control signal  101  from the CCU  103 . 
     FIG. 2B shows the detailed arrangement of the decision unit (detection means)  106  in FIG.  2 A. 
     To detect operation of a control knob  805  on the CCU  103  in FIG. 1 as a change in the CCU control signal  101  in FIG. 2B, the CCU control signal  101  is input to the differential (difference) block  203  of the decision unit  106 . Similarly, to detect operation of the demand  104  connected to the phototaking lens  112  in FIG. 1 as a change in the demand control signal  102  in FIG. 2B, the demand control signal  102  is input to the differential (difference) block  204  of the decision unit  106 . 
     Outputs from the differential blocks  203  and  204  are input to the arithmetic unit  205 . In this case, the differential block  203  and the arithmetic unit  205  form one element of the first detection means. The differential block  204  and the arithmetic unit  205  makes up on element of the second detection means. 
     A priority changeover switch  206  is connected to the arithmetic unit  205 , which has a plurality of algorithms for various focusing operations. After performing the processing shown in FIGS. 3 to  7 , the arithmetic unit  205  determines whether to use a control signal from the CCU  103  or a control signal from the demand  104  to perform driving control of the focus motor  110 , and outputs the determination result to the switching unit  108 . 
     FIG. 3 is a flow chart showing the overall control procedure in this embodiment. Note that the processing in steps  31  to  34  is performed by the decision unit  106  in FIG. 2A, and the processing in step  35  is performed by the decision unit  106 , the switching unit  108 , the driving unit  109 , the focus motor  110 , and the focus mechanism unit  111  in FIG.  2 A. 
     In step  31 , the mode selected by the priority changeover switch  107  in FIG. 2A is detected. In step  32 , a change in the demand control signal  102  from the demand  104  in FIG. 2A is detected by using the differential block  204  of the decision unit  106  in FIG.  2 B. In step  33 , a change in the CCU control signal  101  from the CCU  103  is detected by using the differential block  203  of the decision unit  106  in FIG.  2 B. The processings in steps  32  and  33  are periodically performed by starting a timer or the like at the start of this flow chart. In step  34 , it is checked, on the basis of the control signal detection results in steps  32  and  33 , whether at least one of the signals has changed. If one or both of the control signals have changed, YES is obtained in step  34 . In step  35 , a calculation is performed, and then the motor is driven and/or stopped in accordance with the calculation result. Thereafter, the procedure in FIG. 3 stops. If it is determined in step  34  that neither the demand control signal  102  nor the CCU control signal  101  have changed, NO is obtained in step  34 . As a result, the procedure in FIG. 3 stops. 
     If YES is obtained in step  34  in FIG. 3, one of the operations shown in FIGS. 4 to  7  is performed in step  35  depending on the priority modes described below. 
     FIG. 4 shows focus control in the first press priority mode. 
     In this priority mode, priority is given to that one of the focusing operations with the CCU  103  and the demand  104  which is performed first. That is, other operations are ignored until this first focusing operation is complete. Assume that the control knob of the CCU  103  is operated first. In this case, even if the demand  104  connected to the phototaking lens  112  is operated during a CCU operation, this demand operation is ignored. After the operation of the CCU  103  is complete, the operation of the demand  104  is accepted. In this mode, when a CCU operation and a demand operation are to be performed by different operators, the flow branches to the flow chart of FIG. 4, via “A”, and one operator is inhibited from performing focusing until the other operator completes focusing. In this case, “A” is a symbol used for convenience in connecting the flow charts to each other. 
     Referring to FIG. 4, in step  41 , it is checked whether the priority changeover switch  107  in FIG. 2B is switched to the first press priority mode. If YES in step  41 , information indicating the first press priority mode is displayed on the display means  113  on the phototaking lens  112  or the viewfinder of the camera body in FIG. 2A in step  42 . If the priority changeover switch  107  is not switched to the first press priority mode, NO is obtained in step  41 , and the flow branches to the flow chart of FIG.  5  through “C”. In this case, “C” is a symbol used for convenience in connecting the flow charts to each other. 
     In step  43 , it is checked whether the first signal input to the phototaking lens  112  is sent from the CCU  103  or the demand  104 . If it is determined that the signal is sent from the CCU  103 , the flow branches to step  44 . If it is determined that the signal is sent from the demand  104 , the flow branches to step  45 . If input signals are simultaneously sent from the CCU  103  and demand  104 , the flow branches to a predetermined one of steps  44  and  45 . 
     In step  44 , the output of the switching unit  108  in FIG. 2A is switched to the CCU control signal  101 . In step  45 , the output of the switching unit  108  in FIG. 2A is switched to the demand control signal  102 . After step  44  or  45 , the focus motor  110  is driven by the driving unit  109  on the basis of the control signal selected by the switching unit  108  in step  46 . 
     The processing in step  47  is periodically performed by starting a timer or the like upon starting step  47 . 
     In step  46 , the focus motor  110  is driven. If it is determined in step  47  afterward that the control signal input to the phototaking lens  112  is the same as the signal output in step  43 , the focus motor  110  is continuously driven in step  46 , and the processing in step  47  is periodically performed. 
     If it is determined in step  47  that the signal input to the phototaking lens  112  is different from the signal output in step  43 , or neither the CCU  103  nor the demand  104  have sent a signal, the flow branches to step  48  to stop the focus motor  110 . The flow then returns, via “B”, to the flow chart illustrated in FIG.  3 . 
     FIG. 5 shows focus control in the last press priority mode. 
     In this priority mode, regardless of whether focusing is performed first with the CCU  103  or the demand  104  in FIG. 2A, when an operation different from the first operation is performed, the first operation is immediately switched to the second operation. If, for example, the CCU  103  is operated first, and the demand  104  is then operated during the operation of the CCU  103 , focusing with the CCU  103  is stopped, and focusing with the demand  104  is started. In this mode, priority is given to an operator who performs focusing last. 
     Referring to FIG. 5, it is checked in step  51  whether the priority changeover switch  107  in FIG. 2B is switched to the last press priority mode. If YES in step  51 , information indicating the last press priority mode is displayed on the display means  113  on the phototaking lens  112  or the viewfinder of the camera in FIG. 2A in step  52 . If the priority changeover switch  107  is not switched to the last press priority mode, NO is obtained in step  51 , and the flow branches to the flow chart of FIG. 6, via “D”. In this case, “D” is a symbol used for convenience in connecting the flow charts to each other. 
     In step  53 , it is checked whether the signal input to the phototaking lens  112  is sent from the CCU  103  or the demand  104 . If it is determined that the signal is sent from the CCU  103 , the flow branches to step  54 . If it is determined that the signal is sent from the demand  104 , the flow branches to step  55 . If input signals are simultaneously input from the CCU  103  and the demand  104 , the flow branches to a predetermined one of steps  54  and  55 . 
     In step  54 , the output of the switching unit  108  in FIG. 2A is switched to the CCU control signal  101 . In step  55 , the output of the switching unit  108  in FIG. 2A is switched to the demand control signal  102 . After step  54  or  55 , the focus motor  110  is driven by the driving unit  109  on the basis of the control signal selected by the switching unit  108  in step  56 . 
     The processing in step  57  is periodically performed by starting a timer or the like upon starting step  57 . 
     After the focus motor  110  is driven in step  56 , it is checked in step  57  whether any control signal is input to the phototaking lens  112 . If it is determined that a signal is input from the CCU  103  or the demand  104 , the flow branches to step  53 . The processing in step  53 , step  54  or  55 , step  56 , and  57  is performed again. 
     If it determined in step  57  that neither the CCU  103  nor the demand  104  have sent a signal, the flow branches to step  58  to stop the focus motor. The flow then returns, via “B”, to the flow chart illustrated in FIG.  3 . 
     In this priority mode, priority is given to focusing with the CCU  103  in FIG.  2 A. Even if the demand  104  is operated before this operation is complete, the operation of the demand  104  is ignored. The operation of the demand  104  is accepted only after the operation with the CCU  103  is complete. When the CCU  103  is operated during focusing with the demand  104 , focusing is switched to the operation with the CCU  103 . 
     In this remote priority mode, the CCU  103  of the camera is regarded as the main means for focusing, whereas the demand  104  is regarded as an auxiliary means for focusing. For example, this mode is used for a shooting operation using a monitor camera. Focusing of this camera is basically performed by using the CCU set in a monitoring center or the like. For maintenance or the like, however, a demand is mounted on the lens of the monitor camera to check the focusing movement of the lens. 
     Referring to FIG. 6, it is checked in step  61  whether the priority changeover switch  107  in FIG. 2B is switched to the remote priority mode. If YES in step  61 , information indicating the remote priority mode is displayed on the display means  113  on the phototaking lens  112  or the viewfinder of the camera body in FIG. 2A in step  62 . If the priority changeover switch  107  is not switched to the remote priority mode, NO is obtained in step  61 , and the flow branches to the flow chart of FIG. 7, via “E”. In this case, “E” is a symbol used for convenience in connecting the flow charts to each other. 
     In step  63 , it is checked whether the first signal input to the lens is sent from the CCU  103  or the demand  104 . If it is determined that the signal is sent from the CCU  103 , the flow branches to step  64 . If it is determined that the signal is sent from the demand  104 , the flow branches to step  65 . If it is determined in step  63  that signals are simultaneously input from the CCU  103  and the demand  104 , then the flow branches to step  64 . 
     In step  64 , the output of the switching unit  108  in FIG. 2A is switched to the CCU control signal  101 . In step  65 , the output of the switching unit  108  in FIG. 2A is switched to the demand control signal  102 . After step  64  or  65 , the focus motor  110  is driven by the driving unit  109  on the basis of the control signal selected by the switching unit  108  in step  66 . 
     The processing in step  67  is periodically performed by starting a timer or the like upon starting step  67 . 
     After the focus motor  110  is driven in step  66 , it is checked in step  67  whether any control signal is input to the phototaking lens  112 . If the signal input to the phototaking lens  112  is sent from the CCU  103 , the flow branches to step  64 . The processing in steps  66  and  67  is performed again. 
     If it is determined in step  67  that no signal is input to the CCU  103 , the flow branches to step  68 . 
     If it is determined in step  68  that the control signal input to the phototaking lens  112  is sent from the demand  104 , the flow branches to step  65 . The processing in steps  66  and  67  is then performed again. If it is determined in step  68  that no demand signal is input to the phototaking lens  112 , the focus motor is stopped in step  69 . The flow then returns, via “B”, to the flow chart illustrated in FIG.  3 . 
     FIG. 7 shows focus control in the local priority mode. 
     In this priority mode, priority is given to focusing with the demand  104  in FIG.  2 A. In this mode, even if the CCU  103  is operated before this focusing operation is complete, the operation of the CCU  103  is ignored. The operation of the CCU  103  is accepted only after the operation with the demand  104  is complete. When the operation with the demand  104  is initiated during focusing with the CCU  103 , focusing is switched to focusing with the demand  104 . 
     In this local priority mode, the demand  104  of the phototaking lens is regarded as the main means for focusing, whereas the CCU  103  is regarded as an auxiliary means for focusing. In this mode, the cameraman, who manipulates the lens, normally performs focusing with the demand. When the cameraman moves away from the TV camera with the TV camera and the phototaking lens being fixed, focusing can be performed with the CCU set in a relay car or the like. 
     Referring to FIG. 7, it is checked in step  71  whether the priority changeover switch  107  in FIG. 2B is switched to the local priority mode. If YES in step  71 , information indicating the local priority mode is displayed on the display means  113  on the phototaking lens  112  or the viewfinder of the camera body in FIG. 2A in step  72 . If the priority changeover switch  107  is not switched to the local priority mode, NO is obtained in step  71 . In this case, the flow branches, via “B”, to the step of stopping the focus motor in FIG. 3 without driving the focus motor. 
     In step  73 , it is checked whether the first signal input to the lens is sent from the CCU  103  or the demand  104 . If it is determined that the signal is sent from the demand  104 , the flow branches to step  74 . If it is determined that the signal is sent from the CCU  103 , the flow branches to step  75 . If it is determined in step  73  that signals are simultaneously input from the CCU  103  and the demand  104  to the lens, the flow branches to step  74 . 
     In step  74 , the output of the switching unit  108  in FIG. 2B is switched to the demand control signal  102 . In step  75 , the output of the switching unit  108  in FIG. 2B is switched to the CCU control signal  101 . After step  74  or  75 , the focus motor  110  is driven by the driving unit  109  on the basis of the control signal selected by the switching unit  108  in step  76 . 
     The processing in step  77  is periodically performed by starting a timer or the like upon starting step  77 . 
     After the focus motor  110  is driven in step  76 , it is checked in step  77  whether any control signal is input to the phototaking lens  112 . If the signal input to the phototaking lens  112  is sent from the demand  104 , the flow branches to step  74 . The processing in steps  76  and  77  is then performed again. 
     If it is determined in step  77  that no signal is sent from the demand  104 , the flow branches to step  78 . If it is determined in step  78  that the control signal input to the phototaking lens  112  is sent from the CCU  103 , the flow branches to step  75 . The processing in steps  76  and  77  is then performed again. If it is determined in step  78  that no CCU control signal is input to the phototaking lens  112 , the focus motor is stopped in step  79 . 
     In all the focus modes in FIGS. 4 to  7 , if there is only a demand, focusing can be performed by using only the demand. If there is only a CCU, focusing can be performed by using only the CCU. 
     In the above description, a focus command signal is used as the command signal. Instead of this signal, however, a zoom command signal or an aperture control signal may be used. 
     As has been described above, according to the present invention, there is provided an image pickup apparatus suited for a TV camera, in particular, and a phototaking lens used therein, which can smoothly and reliably perform focusing and zooming of the phototaking lens by using a detection means for detecting the operation states of the demand (focus demand) of the phototaking lens and the control knob of a CCU on the camera body side and automatically switching focusing and zooming on the basis of a signal from the detection means, without using the R/L switch in the CCU, as used in the prior art. 
     According to the present invention, by detecting whether focusing is being done with the focus demand or the CCU in accordance with a change in a focus control signal from the focus demand or the CCU, in particular, operations with the demand of the phototaking lens and the CCU of the camera can be smoothly switched without using the R/L switch of the CCU of the camera. 
     By selectively operating the priority changeover switch mounted in the phototaking lens, one of various operation modes, namely the first press priority mode, the last press priority mode, the remote priority mode, and the local priority mode, can be selected. 
     An image pickup apparatus and a phototaking lens used therein which can perform focusing of the phototaking lens by using only a focusing controller can be obtained even if the controller includes only a demand attached to the phototaking lens or a CCU mounted on the camera.