Abstract:
The present invention relates to a zoom lens having a controller which controls driving of a zoom portion, based on input of zoom control information, and which controls driving of the zoom portion while calculating a target drive state (zoom position) of the zoom portion in order to effect correction for variation in an angle of view with driving of a focus portion. In the present invention the lens of this type is constructed to determine whether the input of the zoom control information is information about the target drive state of the zoom portion (for example, whether the zoom control information is information about the zoom drive state of the zoom portion or information about driving speed of the zoom portion). When the zoom control information is the information about the target drive state, the driving control of the zoom portion for the angle-of-view variation correction is inhibited even with driving of the focus portion, whereby with photographer&#39;s intentional zoom manipulation a zoom state according to the zoom manipulation is achieved, taking precedence over the angle-of-view correction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a zoom lens used in TV cameras and the like. 
     2. Related Background Art 
     The photographic angle of view can be increased or decreased by controlling a zoom portion of a zoom lens to move the lens position, but, with control being effected on a focus portion, the angle of view will also vary similarly because of movement of the lens position. This means that even after a desired angle of view is set by the zoom portion, the angle of view thus set varies with the control on the focus portion. For overcoming it, suggestions have been made heretofore about zoom lenses having the so-called angle-of-view variation correction function of controlling the zoom portion against the variation in the angle of view on the occasion of the control of the focus portion. 
     SUMMARY OF THE INVENTION 
     One aspect of the application is to provide a lens apparatus comprising control means which controls driving of a zoom portion, based on input of zoom control information, and which calculates a target drive state of the zoom portion for correction for variation in an angle of view due to driving of a focus portion to control the driving of the zoom portion, wherein the control means determines whether the zoom control information is information about the target drive state of the zoom portion (for example, whether the zoom control information is information about the target drive state of the zoom portion or information about driving speed of the zoom portion) and wherein the control means inhibits control of the driving of the zoom portion for the correction for variation in the angle of view even with the driving of the focus portion when the zoom control information is the information about the target drive state. 
     One aspect of the application is to provide a lens apparatus wherein the control of the driving of the zoom portion for the correction for variation in the angle of view by the control means is permitted only when the zoom control information is not the information about the target drive state of the zoom portion (for example, when the zoom control information is the information about driving speed of the zoom portion). 
     The other objects of the present invention will become more apparent from the embodiments which will be described hereinafter with reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a structural diagram of the zoom lens which is the first embodiment of the present invention; 
     FIG. 2 is a flowchart to show the operation of the above-stated zoom lens; 
     FIG. 3 is a flowchart to show the operation of the above-stated zoom lens; 
     FIG. 4 is a flowchart to show the operation of the zoom lens which is the second embodiment of the present invention; 
     FIG. 5 is a flowchart to show the operation of the zoom lens of the second embodiment; 
     FIG. 6 is a flowchart to show the operation of the zoom lens which is the third embodiment of the present invention; and 
     FIG. 7 is a flowchart to show the operation of the zoom lens of the third embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     (First Embodiment) 
     FIG. 1 shows the structure of the zoom lens which is the first embodiment of the present invention. This zoom lens  101  is equipped with a zoom demand (manipulating device)  1  and a focus demand  2  to compose a zoom lens system and is connected in a communicable state to a camera  103  to compose a camera system. 
     Reference numeral  5  designates a CPU (control means) and the zoom demand  1  and focus demand  2  are connected to this CPU  5 . Either zoom position data or zoom speed data as zoom control data (zoom control information) corresponding to the manipulating angle of the zoom demand  1  is selected at the zoom demand  1  and the thus selected data is outputted from the zoom demand  1  to the CPU  5 . The CPU  5  also accepts input of focus position data as focus control data corresponding to a manipulation amount of the focus demand  2  therefrom. 
     One output of the CPU  5  is connected via an amplifier  6  to a motor  8  which actuates a lens constituting a zoom portion Z. The zoom portion Z is provided with a position detector  9  which indicates a count value according to an absolute position of the lens. This position detector  9  is connected to the CPU  5 . 
     Another output of the CPU  5  is connected via an amplifier  13  to a motor  15  which actuates a lens constituting a focus portion F. The focus portion F is provided with a position detector  16  which indicates a count value according to an absolute position of the lens. This position detector  16  is connected to the CPU  5 . 
     Another output of the CPU  5  is connected via a D/A converter  20  to the television camera  103 . This enables transmission of follow signals indicating various states of the zoom lens  101 , including zoom follow data which represents the lens position of the zoom portion Z, iris follow data which represents a state of an unrepresented stop, and so on, to the camera  103 . 
     An angle-of-view correction mode changeover switch  4  for on/off changeover of the angle-of-view correction function (angle-of-view correction mode) is connected to the CPU  5 . 
     Further, a nonvolatile memory  3 , which stores data for determining the relation between positions of the lenses respectively constituting the zoom portion Z and the focus portion F (which will be referred hereinafter as zoom position and focus position) and angles of view, is also connected to the CPU  5 . The data stored in the memory  3  will be described below in brief. 
     A lens drive range from the wide-angle extreme to the telephoto extreme of the zoom portion Z is divided into an arbitrary number n of segments, a lens drive range from the infinite extreme to the nearest extreme of the focus portion F is also divided similarly into an arbitrary number m of segments, and output data of pulse-counting counters in the position detectors  9  and  16  is preliminarily calculated in correspondence thereto. The angle of view at the ith zoom divisional point and at the jth focus divisional point is determined by optical computing and, similarly, the angle of view at the ith zoom divisional point and at the (j+1)th focus divisional point, that at the (i+1)th zoom divisional point and at the jth focus divisional point, and that at the (i+1)th zoom divisional point and at the (j+1)th focus divisional point are also determined by optical computing. A relation among the zoom position, focus position, and angle of view in a region surrounded by these four points is approximated by an equation of a plane including three points out of the four points. By applying this equation of the approximate plane, the angle of view can be represented by the function of Eq. (1) below with variables of zoom position and focus position. 
     
       
         ω= Cz×Pz+Cf×Pf+D   (1) 
       
     
     In this equation ω indicates the magnitude of angle of view, Cz a coefficient for the zoom position of the approximate plane, Pz the zoom position, Cf a coefficient for the focus position of the approximate plane, Pf the focus position, and D a constant term of the approximate plane. The memory  3  stores data of a map of the coefficients Cz, Cf, and D determined in this way. 
     The flowchart of FIG.  2  and FIG. 3 shows the sequential operation from immediately after power is turned on in the zoom lens. In these figures, the portions denoted by identical encircled numerals indicate mutual connection thereat. 
     Immediately after power is turned on, the CPU  5  proceeds to step  1  to initialize the interior of the CPU  5 . The CPU also initializes the lens constituting the zoom portion Z and the lens constituting the focus portion F, using outputs from the position detectors  9  and  16 . 
     Then the CPU  5  clears the original angle of view ωorg in step  2  and then goes to step  3  to initialize the serial communication with the zoom demand  1  and with the focus demand  2 . The initialization operation is complete herein and then the CPU transfers to the normal operation to control the zoom portion Z and the focus portion F in accordance with the outputs from the zoom demand  1  and from the focus demand  2 . 
     The CPU  5  accepts input of normalized zoom control data Zvalue from the zoom demand  1  in step  4  and also accepts input of normalized focus control data (focus position data) Fdata from the focus demand  2  in step  5 . Further, the CPU  5  also accepts input of the state of the angle-of-view correction mode changeover switch  4  in step  6 . 
     Next, the CPU determines the state of the angle-of-view correction mode changeover switch  4  in step  7 . When this switch  4  is on, the CPU goes to step  8  to determine the zoom control data Zvalue. When the zoom control data Zvalue is speed data Zspeed, the CPU goes to step  9  to set an angle-of-view correction mode flag. Further, in step  10  the CPU integrates the speed data Zspeed by use of Eq. (2) below to calculate zoom position data Zdata. After that, the CPU proceeds to step  15 . 
     
       
           Zdata=Zbuf+K×Zspeed   (2) 
       
     
     Zbuf: zoom position data upon preceding sampling 
     K: arbitrary integration constant 
     On the other hand, when in step  8  the zoom control data Zvalue is position data Zdata, the CPU goes to step  11  to clear the angle-of-view correction mode flag and then goes to step  15 . 
     When the angle-of-view correction mode changeover switch  4  is off in step  7 , the CPU proceeds to step  12  to determine the zoom control data Zvalue. When it is the speed data Zspeed, the CPU moves to step  13  to integrate the zoom speed data Zspeed by use of above Eq. (2) to calculate the zoom position data Zdata, and then proceeds to step  14 . 
     On the other hand, when in step  12  the zoom control data Zvalue is the position data Zdata, the CPU jumps to step  14 . In step  14  the CPU clears the angle-of-view correction mode flag and then moves to step  15 . 
     In step  15  the CPU substitutes the focus position data Fdata into Eq. (3) below to calculate a focus position command Focus corresponding to the output of the counter in the position detector  16 . 
     
       
         Focus= Far+Fdata/NOM ×(Near−Far)  (3) 
       
     
     Far: infinite-extreme focus command position 
     Near: nearest-extreme focus command position 
     NOM: maximum of normalized focus position data 
     Then the CPU moves to step  16  to set the output of the counter in the position detector  9 , in a counter buffer Zfol and also sets the output of the counter in the position detector  16 , in a counter buffer Ffol. 
     Next, in step  17  the CPU determines the angle-of-view correction mode flag. When the angle-of-view correction mode flag is set, the CPU goes to step  18  to determine the zoom speed data Zspeed. When the zoom speed data Zspeed is 0 (i.e., with a command to stop the zoom portion Z), the CPU proceeds to step  19  to determine whether the original angle of view ωorg is set. 
     When the original angle of view ωorg is cleared in step  19 , the CPU goes to step  20  to read the coefficients of the approximate plane equation corresponding to the region including the counter buffers Zfol and Ffol out of the memory  3  and substitute the read coefficients and the values of the counter buffers into Eq. (1) to calculate the original angle of view ωorg. Then the CPU goes to step  21 . When the original angle of view (ωorg is set in step  19 , the CPU jumps to step  21 . 
     In step  21 , the CPU reads the coefficients of the approximate plane equation corresponding to the region including the counter buffer Zfol and the focus position command Focus out of the memory  3  and substitutes the read coefficients Cz′, Cf′, D, the original angle of view ωorg, and the focus position command Focus into Eq. (4) below to calculate a zoom position command Zoom corresponding to the output of the counter in the position detector  9 . Then the CPU goes to step  24 . 
     
       
         Zoom=(ω org−Cf ′×Focus− D )/ Cz′   (4) 
       
     
     On the other hand, when in step  18  the zoom speed data Zspeed is not equal to 0 (i.e., with a command to actuate the zoom portion Z) or when in step  17  the angle-of-view correction mode flag is cleared, the CPU jumps to step  22  to clear the original angle of view ωorg. Further, the CPU goes to step  23  to substitute the zoom position data Zdata into Eq. (5) below to calculate the zoom position command Zoom corresponding to the output of the counter in the position detector  16 , and then goes to step  24 . 
     
       
         Zoom=Wide+ Zdata/NOM ×(Tele−Wide)  (5) 
       
     
     Wide: wide-angle-extreme zoom position command 
     Tele: telephoto-extreme zoom position command 
     NOM: maximum of normalized zoom position data 
     After the zoom position command Zoom is calculated in this way, the CPU goes to step  24  to perform position control calculation of the zoom portion Z using this zoom position command Zoom and the counter buffer Zfol and also perform position control calculation of the focus portion F using the focus position command Focus and the counter buffer Ffol. 
     In step  25  the CPU then outputs the result of the position control calculation of the zoom portion Z acquired in step  24  to the amplifier  6  to actuate the motor  8 . The CPU also outputs the result of the position control calculation of the focus portion F to the amplifier  13  to actuate the motor  15 . 
     After that, the CPU repeatedly carries out the operation from step  4  to step  25  before power becomes off. 
     In the present embodiment, as described above, with the angle-of-view correction mode changeover switch  4  being on (i.e., when the angle-of-view correction mode is on) (step  7 ), the zoom position command for the angle-of-view variation correction is calculated only when the zoom control data supplied from the zoom demand  1  is the zoom speed data (step  8 ) and when the zoom speed data is equal to 0 (step  18 ). For this reason, when the focus position data is supplied from the focus demand  2  with the zoom speed data of 0 being supplied from the zoom demand  1 , the zoom portion Z is also driven so as to keep the angle of view constant with driving of the focus portion F. 
     On the other hand, when the zoom control data supplied from the zoom demand  1  is the zoom position data with the angle-of-view correction mode changeover switch  4  being on, the angle-of-view correction mode flag is cleared (step  11 ) and the zoom position command is calculated based on the above zoom position data (step  23 ), without execution of the calculation of the zoom position command for the angle-of-view variation correction. 
     (Second Embodiment) 
     The flowchart of FIG.  4  and FIG. 5 shows the sequential operation from immediately after on of power in the zoom lens which is the second embodiment of the present invention. In these figures the portions denoted by identical encircled numerals indicate mutual connection thereat. 
     The first embodiment was described as to the case in which the zoom control data and the focus control data was supplied from the zoom demand  1  and from the focus demand  2 , respectively, but the present embodiment will be described as to a case in which the zoom control data and the focus control data is supplied from the camera connected in the communicable state to the zoom lens. 
     The present embodiment is applied to camera systems including the zoom lens of structure similar to the zoom lens illustrated in FIG.  1 . Therefore, common components will be denoted by the same reference symbols as in the first embodiment. It is, however, noted that the two demands  1 ,  2  do not always have to be connected to the zoom lens  101  in the present embodiment. 
     A communication terminal of the camera  103  is connected via an A/D converter  21  to the CPU  5  of the zoom lens  101  of FIG. 1, and the zoom control data and the focus control data is entered from the camera  103  through the A/D converter  21  into the zoom lens  101  (CPU  5 ). The camera selectively outputs either speed or position data as the zoom control data. 
     Immediately after on of power, the CPU  5  goes to step  31  to initialize the interior of the CPU  5 . The CPU  5  also initializes the lens constituting the zoom portion Z and the lens constituting the focus portion F, using the outputs from the position detectors  9  and  16 . 
     Next, the CPU clears the original angle of view ωorg in step  32  and initializes the serial communication with the camera  103  in step  33 . The initialization operation is complete herein and then the CPU transfers to the normal operation to control the zoom portion Z and the focus portion F in accordance with the output from the camera  103 . 
     The CPU accepts input of normalized zoom control data Zvalue from the camera  103  in step  34  and also accepts input of normalized focus control data (focus position data) Fdata from the camera  103  in step  35 . Further, the CPU accepts input of the state of the angle-of-view correction mode changeover switch  4  in step  36 . 
     Next in step  37  the CPU determines the state of the angle-of-view correction mode changeover switch  4 . When this switch  4  is on, the CPU goes to step  38  to determine the zoom control data Zvalue. When the zoom control data Zvalue is the speed data Zspeed, the CPU goes to step  39  to set the angle-of-view correction mode flag. Further, the CPU goes to step  40  to integrate the speed data Zspeed by use of Eq. (2), which was described in the first embodiment, to calculate the zoom position data Zdata. After that, the CPU goes to step  45 . 
     On the other hand, when in step  38  the zoom control data Zvalue is the position data Zdata, the CPU moves to step  41  to clear the angle-of-view correction mode flag, and then goes to step  45 . 
     When in step  37  the angle-of-view correction mode changeover switch  4  is off, the CPU moves to step  42  to determine the zoom control data Zvalue. When it is the speed data Zspeed, the CPU goes to step  43  to integrate the zoom speed data Zspeed by use of above Eq. (2) to calculate the zoom position data Zdata, and then goes to step  44 . 
     On the other hand, when in step  42  the zoom control data Zvalue is the position data Zdata, the CPU jumps to step  44 . The CPU clears the angle-of-view correction mode flag in step  44  and then proceeds to step  45 . 
     In step  45  the CPU substitutes the focus position data Fdata into Eq. (3), which was described in the first embodiment, to calculate the focus position command Focus corresponding to the output of the counter in the position detector  16 . 
     Then the CPU proceeds to step  46  to set the output of the counter in the position detector  9 , in the counter buffer Zfol and sets the output of the counter in the position detector  16 , in the counter buffer Ffol. 
     Next, the CPU goes to step  47  to determine the angle-of-view correction mode flag. When the angle-of-view correction mode flag is set, the CPU goes to step  48  to determine the zoom speed data Zspeed. When the zoom speed data Zspeed is 0 (i.e., with a command to stop the zoom portion Z), the CPU goes to step  49  to determine whether the original angle of view ωorg is set. 
     When the original angle of view ωorg is cleared in step  49 , the CPU reads the coefficients of the approximate plane equation corresponding to the region including the counter buffers Zfol and Ffol out of the memory  3  and substitutes the read coefficients and the values of the counter buffers into Eq. (1), which was described in the first embodiment, to calculate the original angle of view ωorg in step  50 . Then the CPU goes to step  51 . When the original angle of view ωorg is set in step  49 , the CPU jumps to step  51 . 
     In step  51 , the CPU reads the coefficients of the approximate plane equation corresponding to the region including the counter buffer Zfol and the focus position command Focus out of the memory  3  and substitutes the read coefficients Cz′, Cf′, D, the original angle of view ωorg, and the focus position command Focus into Eq. (4), which was described in the first embodiment, to calculate the zoom position command Zoom corresponding to the output of the counter in the position detector  9 . Then the CPU goes to step  54 . 
     On the other hand, when in step  48  the zoom speed data Zspeed is not equal to 0 (i.e., with a command to actuate the zoom portion Z) or when in step  47  the angle-of-view correction mode flag is cleared, the CPU jumps to step  52  to clear the original angle of view ωorg. Further, the CPU goes to step  53  to substitute the zoom position data Zdata into Eq. (5), which was described in the first embodiment, to calculate the zoom position command Zoom corresponding to the output of the counter in the position detector  16 , and then goes to step  54 . 
     After the zoom position command Zoom is calculated in this way, the CPU goes to step  54  to perform the position control calculation of the zoom portion Z using this zoom position command Zoom and the counter buffer Zfol and also perform the position control calculation of the focus portion F using the focus position command Focus and the counter buffer Ffol. 
     Then the CPU goes to step  55  to output the result of the position control calculation of the zoom portion Z acquired in step  54  to the amplifier  6  to actuate the motor  8 . The CPU also outputs the result of the position control calculation of the focus portion F to the amplifier  13  to actuate the motor  15 . 
     After that, the CPU repeatedly carries out the operation from step  34  to step  55  before power becomes off. 
     In the present embodiment, as described above, with the angle-of-view correction mode changeover switch  4  being on (i.e., when the angle-of-view correction mode is on) (step  37 ), the zoom position command for the angle-of-view variation correction is calculated and the driving control of the zoom portion Z is permitted only when the zoom control data supplied from the camera  103  is the zoom speed data (step  38 ) and when the zoom speed data is equal to 0 (step  48 ). For this reason, when the focus position data is supplied from the camera  103  with the zoom speed data of 0 being supplied from the camera  103 , the zoom portion Z is also driven so as to keep the angle of view constant with driving of the focus portion F. 
     On the other hand, when the zoom control data supplied from the camera  103  is the zoom position data with the angle-of-view correction mode changeover switch  4  being on, the angle-of-view correction mode flag is cleared (step  41 ) and the zoom position command is calculated based on the above zoom position data (step  53 ), without execution of the calculation of the zoom position command for the angle-of-view variation correction. Namely, the driving control of the zoom portion Z for the angle-of-view variation correction is inhibited. 
     (Third Embodiment) 
     The flowchart of FIG.  6  and FIG. 7 shows the sequential operation from immediately after on of power in the zoom lens which is the third embodiment of the present invention. In these figures the portions denoted by identical encircled numerals indicate mutual connection thereat. 
     Each of the first and second embodiments was described as to the case in which the zoom control data and focus control data was supplied from either of the demands  1 ,  2  and the camera  103 , whereas the present embodiment will be described as to a case in which the zoom control data and focus control data is supplied from the both of the demands  1 ,  2  and the camera  103 . 
     The present embodiment is applied to camera systems including the zoom lens of structure similar to the zoom lens illustrated in FIG. 1, and the demands  1 ,  2 . Therefore, the common components will be denoted by the same reference symbols as in the first embodiment. 
     The communication terminal of the camera  103  is connected via the A/D converter  21  to the CPU  5  of the zoom lens  101 , as also described in the second embodiment, and the zoom control data and the focus control data is entered from the camera  103  via the A/D converter  21  into the zoom lens  101  (CPU  5 ). The zoom control data and the focus control data is also supplied from the zoom demand  1  and from the focus demand  2  to the zoom lens  101  (CPU  5 ), as described in the first embodiment. 
     Immediately after on of power, the CPU  5  moves to step  60  to initialize the interior of the CPU  5 . The CPU also initializes the lens constituting the zoom portion Z and the lens constituting the focus portion F, using the outputs from the position detectors  9 ,  16 . 
     Next, the CPU clears the original angle of view ωorg in step  61  and then initializes the serial communication with the zoom demand  1 , with the focus demand  2 , and with the camera  103  in step  62 . The initialization operation is complete herein and then the CPU transfers to the normal operation to control the zoom portion Z and the focus portion F in accordance with the output from the zoom demand  1 , from the focus demand  2 , or from the camera  103 . 
     First, in step  63  the CPU determines whether the control data is received from the camera  103  (remote) or from the demands  1 ,  2  (local). 
     In the remote case, the CPU accepts input of the normalized zoom control data Zvalue and the normalized focus control data (focus position data) Fdata from the camera  103  in steps  64   a,    65   a.  On the other hand, in the local case the CPU accepts input of the normalized zoom control data Zvalue and the normalized focus control data Fdata from the respective demands  1 ,  2  in steps  64   b,    65   b.    
     Further, the CPU accepts input of the state of the angle-of-view correction mode changeover switch  4  in step  66 . 
     Next, the CPU goes to step  67  to determine the state of the angle-of-view correction mode changeover switch  4 . When this switch  4  is on, the CPU goes to step  68  to determine the zoom control data Zvalue. When the zoom control data Zvalue is the speed data Zspeed, the CPU goes to step  69  to set the angle-of-view correction mode flag. Further, the CPU goes to step  70  to integrate the speed data Zspeed by use of Eq. (2), which was described in the first embodiment, to calculate the zoom position data Zdata. After that, the CPU proceeds to step  75 . 
     On the other hand, when in step  68  the zoom control data Zvalue is the position data Zdata, the CPU goes to step  71  to clear the angle-of-view correction mode flag, and then moves to step  75 . 
     When in step  67  the angle-of-view correction mode changeover switch  4  is off, the CPU goes to step  72  to determine the zoom control data Zvalue. When it is the speed data Zspeed, the CPU goes to step  73  to integrate the zoom speed data Zspeed by use of above Eq. (2) to calculate the zoom position data Zdata, and then goes to step  74 . 
     On the other hand, when in step  72  the zoom control data Zvalue is the position data Zdata, the CPU jumps to step  74 . The CPU clears the angle-of-view correction mode flag in step  74  and then goes to step  75 . 
     In step  75 , the CPU substitutes the focus position data Fdata into Eq. (3), which was described in the first embodiment, to calculate the focus position command Focus corresponding to the output of the counter in the position detector  16 . 
     Then the CPU goes to step  76  to set the output of the counter in the position detector  9 , in the counter buffer Zfol and also sets the output of the counter in the position detector  16 , in the counter buffer Ffol. 
     Next, the CPU goes to step  77  to determine the angle-of-view correction mode flag. When the angle-of-view correction mode flag is set, the CPU goes to step  78  to determine the zoom speed data Zspeed. When the zoom speed data Zspeed is 0 (i.e., with a command to stop the zoom portion Z), the CPU proceeds to step  79  to determine whether the original angle of view ωorg is set. 
     When the original angle of view ωorg is cleared in step  79 , the CPU reads the coefficients of the approximate plane equation corresponding to the region including the counter buffers Zfol and Ffol out of the memory  3  and substitutes the read coefficients and the values of the counter buffers into Eq. (1), which was described in the first embodiment, to calculate the original angle of view ωorg in step  80 . Then the CPU goes to step  81 . When the original angle of view ωorg is set in step  79 , the CPU jumps to step  81 . 
     In step  81  the CPU reads the coefficients of the approximate plane equation corresponding to the region including the counter buffer Zfol and the focus position command Focus out of the memory  3  and then substitutes the read coefficients Cz′, Cf′, D, the original angle of view ωorg, and the focus position command Focus into Eq. (4), which was described in the first embodiment, to calculate the zoom position command Zoom corresponding to the output of the counter in the position detector  9 . Then the CPU goes to step  84 . 
     On the other hand, when in step  78  the zoom speed data Zspeed is not equal to 0 (i.e., with a command to actuate the zoom portion Z) or when in step  77  the angle-of-view correction mode flag is cleared, the CPU jumps to step  82  to clear the original angle of view ωorg. Further, the CPU goes to step  83  to substitute the zoom position data Zdata into Eq. (5) described in the first embodiment, to calculate the zoom position command Zoom corresponding to the output of the counter in the position detector  16 , and then goes to step  84 . 
     After the zoom position command Zoom is calculated in this way, the CPU goes to step  84  to perform the position control calculation of the zoom portion Z using the zoom position command Zoom and the counter buffer Zfol and also perform the position control calculation of the focus portion F using the focus position command Focus and the counter buffer Ffol. 
     Then the CPU goes to step  85  to output the result of the position control calculation of the zoom portion Z acquired in step  84  to the amplifier  6  to actuate the motor  8 . The CPU also outputs the result of the position control calculation of the focus portion F to the amplifier  13  to actuate the motor  15 . 
     After that, the CPU repeatedly carries out the operation from step  63  to step  85  before power becomes off. 
     In the present embodiment, as described above, with the angle-of-view correction mode changeover switch  4  being on (i.e., when the angle-of-view correction mode is on) (step  67 ), the zoom position command for the angle-of-view variation correction is calculated only when the zoom control data supplied from the zoom demand  1  or from the camera  103  is the zoom speed data (step  68 ) and when the zoom speed data is equal to 0 (step  78 ). For this reason, when the focus position data is supplied from the focus demand  2  or from the camera  103  with the zoom speed data of 0 being supplied from the zoom demand  1  or from the camera  103 , the zoom portion Z is also driven so as to keep the angle of view constant with driving of the focus portion F. 
     On the other hand, when the zoom control data supplied from the zoom demand  1  or from the camera  103  is the zoom position data with the angle-of-view correction mode changeover switch  4  being on, the angle-of-view correction mode flag is cleared (step  71 ) and the zoom position command is calculated based on the above zoom position data (step  83 ), without execution of the calculation of the zoom position command for the angle-of-view variation correction.