JP3940818B2 - Lens for TV camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a TV camera lens, and more particularly to a TV camera lens drive control technique in which movement control of a master lens group is performed by position control and speed control.
[0002]
[Prior art]
In a broadcast television camera, a master lens group of a photographing lens system is moved back and forth along an optical axis. This forward / backward movement is performed by position control and speed control. In such a television camera lens configured to move the master lens group by position control and speed control, the position control and speed control are switched according to the purpose.
[0003]
When adjusting the tracking position, the master lens group is moved by position control to finely adjust (track) the lens imaging position. As a result, the master lens group can be moved to the tracking position.
On the other hand, the master lens group is intentionally moved in order to achieve a special effect of the image, and when the photographed image is blurred, the master lens group is moved by speed control. When performing such blur shooting, the master lens group is moved from the previously set tracking position at a desired speed.
[0004]
[Problems to be solved by the invention]
However, there is a problem that it is difficult to control the speed of the master lens group from a blurred state and to stop it accurately at the tracking position once adjusted.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a television camera lens that can be reliably stopped at a desired position while controlling the speed of a master lens group.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides position control means for position-controlling movement of a master lens group disposed in a lens body, speed control means for speed-controlling movement of the master lens group, A position / speed switching means for selecting one of the position control means and the speed control means and enabling the control by the selected control means; and the position control means at the time of the speed control by the speed control means. Limit means for setting the controlled position as a limit position for limiting a movable range of the master lens group.
[0006]
According to the present invention, the position / velocity switching means selects the control by the position control means, and moves the master lens group by controlling the position.
Thereafter, the position / speed switching means selects the control by the speed control means, and the master lens group is moved by speed control. At this time, the position previously controlled by the position control means is set to a limit position within a range that can be moved by speed control. As a result, the master lens group whose speed is controlled by the speed control means cannot move beyond the limit position. Therefore, the master lens group can be stopped at the same position as the position where the position was first controlled by the speed control.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a television camera lens according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a side view of a lens for a television camera to which the present invention is applied, and the internal structure is partially shown. The portion covered with the hood 11 on the left side in the figure is in front of the lens body 10, and the TV camera is fixedly connected to the right end surface in the figure. The lens body 10 is covered with a substantially rectangular cover 12, and the cover 12 is detachably fixed to the lens body 10 by fixing screws 14 provided on the left and right side surfaces. A concave portion 16 is formed at the upper center of the side surface of the cover 12 and serves as a handle for carrying the lens. A tally lamp window 18 is formed in front of the concave portion 16.
[0010]
Although the inside of the lens body 10 is not shown in detail, a fixed focus lens group, a moving focus lens group, a first moving zoom lens group, and a second moving zoom lens group are arranged in the lens barrel of the lens body 10 in order from the front side. And a master lens group 20 and the like.
The master lens group 20 of the photographing lens system is held by a lens holding cylinder 22 and is connected to the rearmost part of the fixed barrel 24 so as to be movable in the front-rear direction. A guide hole parallel to the axis is formed on the peripheral surface of the fixed barrel 24, and a pin 26 implanted in the lens holding tube 22 is fitted into the guide hole. Further, a cam groove 28 that is rotatably mounted on the outer peripheral surface of the fixed barrel 24 is formed with a cam groove having a constant width in an oblique direction with respect to the axis, and the pin 26 of the lens holding cylinder 22 is The cam groove is fitted.
[0011]
The lens body 10 is provided with a drive motor 30 for driving the master lens group 20 and a potentiometer 32 for detecting the position of the master lens group 20. The driving force of the motor 30 is transmitted to the cam cylinder 28 by gears 34 and 35. When the cam barrel 28 rotates, the lens holding barrel 22 moves back and forth with respect to the fixed barrel 24. The potentiometer 32 outputs a position detection signal indicating the position of the master lens group 20 in accordance with the amount of rotation.
[0012]
A rotary flange back adjustment knob 42 for operating the driving of the master lens group 20 is provided behind the cover 12 and at the lower side of the side surface of the mount frame 40. The flange back adjustment knob 42 is provided with a potentiometer (not shown), and a position command signal corresponding to the rotation amount of the knob is output. This position command signal is input to a control circuit 52 (not shown in FIG. 1), and the motor 30 is driven by a servo signal corresponding to the position command signal. When the motor 30 rotates, the rotational force is transmitted to the potentiometer 32 and the cam cylinder 28 via the gear, and the lens holding cylinder 22 moves back and forth along the optical axis.
[0013]
Accordingly, by rotating the flange back adjustment knob 42, the master lens group 20 is moved forward and backward along the optical axis by position control, and the imaging position of the lens is adjusted (tracking adjustment) on the image receiving surface of the television camera. be able to.
A fixed knob 44 is provided on the same axis as the flange back adjusting knob 42. The fixed knob 44 is for locking the rotation of the flange back adjusting knob 42 so that the tracking position adjusted by the flange back adjusting knob 42 does not shift. That is, after adjusting the position of the master lens group 20 by operating the flange back adjustment knob 42, when the fixing knob 44 is turned clockwise, the rotation of the rotation shaft of the flange back adjustment knob 42 is fixed. It is possible to prevent the position of the master lens group once adjusted from receiving an unexpected external force and moving.
[0014]
Next, the drive control system of the master lens group will be described.
FIG. 2 is a block diagram showing the configuration of the drive control system of the master lens group. The TV camera lens 100 is provided with a position control signal generating means 50 for controlling the master lens group 20, a control circuit 52, a limit circuit 65, and the like.
[0015]
The position control signal generating means 50 corresponds to the flange back adjustment knob 42 shown in FIG. 1 and the potentiometer provided on the knob 42. When the flange back adjustment knob 42 is rotated, the position control signal generating means 50 is controlled according to the amount of rotation. An electric signal for instructing the moving position of the lens group 20 is output. This electric signal is input to the control circuit 52.
[0016]
The control circuit 52 outputs a servo signal corresponding to the input electric signal and drives the motor 30. When the motor 30 rotates, the cam cylinder 28 is rotated by the rotational force as described above, and the master lens group 20 moves back and forth along the optical axis. The position of the master lens group 20 is detected by the potentiometer 32, and the position detection signal is notified to the control circuit 52. The control circuit 52 stops driving the motor 30 when the position indicated by the position detection signal coincides with the position commanded from the position control signal generating means 50. Thereby, position control with high followability is possible.
[0017]
In addition, a tachometer generator 53 is connected to the motor 30, and the tachometer generator 53 detects the rotation speed of the motor 30. A signal from the tacho generator 53 is added to the control circuit 52 and used for speed control of the motor 30.
On the other hand, a speed control controller 60 is connected to the TV camera lens 100. The speed control controller 60 includes a speed control signal generator 61 for generating a speed command signal, a speed command signal from the speed control signal generator 61 and a position command signal from the position control signal generator 50. A position / speed changeover switch 62 is provided for selectively setting which command signal is prioritized.
[0018]
When the position / speed switch 62 is set to the “position” side, a signal indicating that is applied to the control circuit 52 on the lens 100 side, and the command from the position control signal generating means 50 becomes valid, and the speed control signal generating means The speed command from 61 becomes invalid. That is, the control circuit 52 side ignores the speed command signal from the speed control signal generating means 61 and outputs a servo signal based on the position command signal from the position control signal generating means 50. As a result, the master lens group 20 is driven by the motor 30 and the tracking position is adjusted.
[0019]
On the other hand, when the position / speed changeover switch 62 is set to the “speed” side, a signal indicating that is added to the control circuit 52 via the limit circuit 65, and the speed command from the speed control signal generating means 61 becomes valid, The command from the position control signal generating means 50 becomes invalid. That is, the control circuit 52 ignores the command signal from the position control signal generating means 50 and outputs a servo signal based on the speed command signal from the speed control signal generating means 61.
[0020]
At this time, the previously adjusted tracking position is input to the limit circuit 65 from the position control signal generating means 50, and the tracking position is set to a limit position that limits the movable range of the master lens group 20. Is done. The limit circuit 65 is notified of the position of the master lens group 20 detected by the potentiometer 32, and prevents the master lens group 20 from moving outside the movable range. As a result, the master lens group 20 can be reliably returned to the previously adjusted tracking position by speed control.
[0021]
A limit ON / OFF switch 66 is connected to the limit circuit 65, and the movement limitation due to the speed control limit position can be released. Thereby, normal speed control can be performed.
Further, the limit circuit 65 is connected to a speed control range changeover switch 67 so that the movable range in the speed control can be changed from the limit position to the forward moving end and from the limit position to the backward moving end. Either one can be selected. Although the limit circuit 65 is provided on the TV camera lens 100 side, it may be provided on the speed control controller 60 side.
[0022]
The operation of the TV camera lens configured as described above will be described.
First, the position / speed changeover switch 62 shown in FIG. 2 is set to the tracking control side, and the command signal from the position control signal generating means 50 is validated. Then, while adjusting the flange back adjustment knob 42 and confirming the image formation state with the viewfinder 122 of the television camera 120, the optimum focus position (tracking position) is adjusted (see FIG. 5).
[0023]
When the tracking position is determined, the fixed knob 44 is rotated to lock the rotation of the flange back adjustment knob 42 so that the adjusted tracking position does not shift due to an unexpected external force or the like.
In normal shooting thereafter, for example, as shown in FIG. 5, the focus lens (moving focus lens group) is moved by operating the focus demand (focus ring) 124 with the right hand to adjust the focus, and the left hand is zoomed. By operating the ring 126, the zoom lens group (the first and second zoom lens groups) is moved while being defined by a predetermined optical positional relationship to perform zooming adjustment. A position control signal is output from the focus ring 124, and the focus lens is driven based on this position control. On the other hand, a speed control signal is output from the zoom controller including the zoom ring 126, and the zoom lens group is driven under speed control based on the speed control signal.
[0024]
When shooting with a special effect, the position / speed switch 62 shown in FIG. 2 is set on the speed control controller 60 side, and the command from the speed control signal generating means 61 is validated. At this time, the signal from the position control signal generation means 50 is ignored, but the position command state indicating the previously adjusted tracking position is maintained.
[0025]
For example, in order to obtain a special effect on the image that one image is blurred by blur shooting, the master lens group 20 is intentionally moved to aim at the image effect. In this case, the position / speed switch 62 shown in FIG. 2 is set to the “speed” side, and the command from the speed control signal generating means 61 is validated. Then, the moving range of the master lens group 20 is set by the speed control range switch 67, and the master lens group 20 is moved by operating the operation member of the speed control signal generating means 61. The master lens group 20 is speed-controlled from the tracking position, moves smoothly along the optical axis, and the image is blurred with a natural feeling. An operation aiming at such a special effect can be easily performed.
[0026]
Further, when moving the master lens group 20 from the blurred state to the previously adjusted tracking position by speed control, the master lens group 20 is moved in the direction of the tracking position at a desired speed. When the position of the master lens group 20 is detected by the potentiometer 32 and the limit circuit 65 is notified that the master lens group 20 is at the previously set limit position, the speed command is forcibly set to 0 and the motor 30 is driven. Is stopped. Thereby, the master lens group 20 can be reliably moved to the previously adjusted tracking position by speed control.
[0027]
If a limit release signal is input to the limit circuit 65 by the limit ON / OFF switch 66, the stop control at the limit position is released and normal speed control can be performed. Also, when performing macro photography, the movement of the master lens group 20 is performed by speed control. In this case, the zoom can be adjusted by operating the zoom ring 126 shown in FIG. 5 and moving the zoom lens group. When the position / speed changeover switch 62 is set to the “position” side again after an operation intended for the special effect or macro shooting, the command signal from the position control signal generating means 50 becomes effective and the previously adjusted tracking is performed. Automatically return to position.
[0028]
As described above, once the tracking position is set, even when the speed control controller 60 is arbitrarily operated, the tracking position command is maintained on the position control signal generating means 50 side. It can be automatically restored accurately.
FIG. 3 is a block diagram showing another embodiment of the drive control system of the master lens group in the TV camera lens according to the present invention. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 2, and the detailed description is abbreviate | omitted. Further, the first limit circuit 68 and the first limit ON / OFF switch 69 shown in FIG. 3 have the same functions as the limit circuit 65 and the limit ON / OFF switch 66 shown in FIG. 2, respectively. .
[0029]
The embodiment shown in FIG. 3 is different from the embodiment shown in FIG. 2 in that a speed control controller 70 is provided instead of the speed control controller 60 shown in FIG.
In addition to the speed control signal generating means 61 and the position / speed changeover switch 62 shown in FIG. 2, the speed control controller 70 newly includes a limit signal generating means 72, a second limit ON / OFF switch 70, and a second limit ON / OFF switch 70. Two limit circuits 76 are provided.
[0030]
The limit signal generating means 72 manually sets a position (second limit position) for limiting the movement of the master lens group 20, and outputs an electric signal for instructing the second limit position. This electric signal is input to the second limit circuit 76.
A speed command signal is applied from the speed control signal generating means 61 to the second limit circuit 76, and a position detection signal indicating the position of the master lens group 20 is added to the potentiometer 32. The second limit circuit 76 normally outputs the speed command signal from the speed control signal generating means 61 to the first limit circuit 68 as it is, but the movement position of the master lens group 20 detected by the potentiometer 32 is the limit signal generation. When the second limit position set by the means 72 is reached, the speed command sent to the first limit circuit 68 is made zero regardless of the speed command output from the speed control signal generating means 61. As a result, when the speed of the master lens group 20 is controlled, the second limit position set by the limit signal generating means 72 can be accurately set in addition to the position adjusted by the position control signal generating means 50 (first limit position). Can be stopped. Although the limit circuit 76 is provided on the speed control controller 70 side, it may be provided on the TV camera lens side in the same manner as the first limit circuit 68.
[0031]
FIG. 4 is a conceptual diagram showing the movement range of the master lens group 20 in the embodiment shown in FIG. In the figure, positions A and B are mechanical limit positions at which the master lens group 20 can move. The position C is the first limit position adjusted by the position control signal generating means 50.
Here, the position D is set as the second limit position in FIG. 4 by the limit signal generating means 72, and the speed control between the positions A and C is selected by the speed control range changeover switch 67. The movement range of the master lens group 20 can be moved only between positions CD. The second limit position D can also be set between the positions CB, but in this case, the speed control between the positions CB needs to be selected by the speed control range changeover switch 67. In this embodiment, there is only one limit signal generating means 72 for setting the position D. However, two limit signal generating means are provided, and two limit positions at the left end and the right end can be set in FIG. You may do it.
[0032]
In this embodiment, the case where the entire master lens group is moved has been described. However, the present invention can also be applied to a case where a part of the lenses constituting the master lens group is moved.
Next, the tracking position of the master lens group during normal shooting and the position of the master lens group during macro shooting (hereinafter referred to as “macro position”) can be set to desired positions, and the macro position during normal shooting can be set. An embodiment of a lens for a television camera in which the position can be used as the second limit position will be described.
[0033]
FIG. 6 is a diagram showing the configuration of the drive control system of the master lens group in this case, and FIG. 7 is a front view showing the appearance of the controller that controls the master lens group. As shown in FIG. 6, the TV camera lens 200 is provided with a position control signal generating means 50, a switching circuit 202, a control circuit 204, a master lens group 20, and the like. A controller 220 has a macro position setting means 222, a macro A switching unit 224 and a speed adjusting unit 226 are provided. Macro position setting means 222, macro switching means 224 and speed adjustment means 226 of controller 220 are operated by members of macro position adjustment knob 230, macro changeover switch 232 and speed adjustment knob 234, respectively, as shown in FIG. It has become.
[0034]
The position control signal generating means 50 shown in FIG. 6 is the same as that described in the above embodiment, and when the flange back adjusting knob 42 shown in FIG. 1 is rotated, the potentiometer of the position control signal generating means 50 is used. 50A outputs a voltage signal corresponding to the rotational position to the switching circuit 202. As described above, the position control signal generator 50 sets the tracking position, that is, the first limit position. FIG. 8 shows a tracking position (first limit position) a set for the entire movement range (AB) of the master lens group 20.
[0035]
The macro position setting means 222 of the controller 220 has a potentiometer 222A. When the macro position adjustment knob 230 shown in FIG. 7 is rotated, the potentiometer 222A sends a voltage signal corresponding to the rotation position to the switching circuit 202. Output. As will be described later, the macro position setting means 222 sets the macro position of the master lens group 20 during macro photography. FIG. 8 shows the macro position b with respect to the entire movement range of the master lens group 20, and this macro position acts as the second limit position for limiting the movable range of the master lens group 20.
[0036]
The switching circuit 202 switches the on / off state of the switches 202A and 202B based on the state of the selector switch 224A of the macro switching unit 224 of the controller 220, and the voltage signal from the position control signal generating unit 50 and the macro One of the voltage signals from the position setting means 220 is output to the control circuit 204 at the next stage.
[0037]
That is, when the changeover switch 224A of the macro changeover means 224 linked to the macro changeover switch 232 shown in FIG. 7 is turned off, the transistor 202C of the changeover circuit 202 is turned on. In this case, the switch 202A is turned on. At the same time, the switch 202B is turned off. As a result, the operation of the macro position setting unit 222 becomes invalid, the operation of the position control signal generation unit 50 becomes valid, and the voltage signal from the position control signal generation unit 50 is input to the control circuit 204.
[0038]
On the other hand, when the changeover switch 224B of the macro switching unit 224 is turned on, the transistor 202C is turned off. In this case, the switch 202A is turned off and the switch 202B is turned on. As a result, the operation of the position control signal generating means 50 becomes invalid, the operation of the macro position setting means 222 becomes valid, and the voltage signal from the macro position setting means 222 is input to the control circuit 204.
[0039]
The control circuit 204 moves the master lens group 20 to the position indicated by the voltage signal input from the switching circuit 202, and executes the movement at the speed adjusted by the speed adjusting means 226. Specifically, the voltage signal input from the switching circuit 202 is input to the negative terminal of the differential amplifier 202B via the buffer 204A, and the voltage signal from the potentiometer 32 that detects the position of the master lens group 20 is differentially input. Input to the + terminal of the amplifier. Then, the difference between these voltage signals is amplified and input to the motor drive circuit 204C via the speed adjustment means 226 of the controller 220. That is, the difference between the position of the master lens group 20 designated by the position control signal generating means 50 or the macro position setting means 222 and the current position of the master lens group 20 is detected, and the voltage signal indicating the difference is speed adjusted. The signal is input to the motor drive circuit 204C through the means 226.
[0040]
The speed adjustment means 226 has a potentiometer 226A, and the position of the slider terminal (output terminal) of the potentiometer 226A changes in conjunction with the rotational position of the speed adjustment knob 234 shown in FIG. Yes. As a result, the voltage signal input from the control circuit 204 is converted into a voltage signal corresponding to the rotational position of the speed adjusting knob 234.
[0041]
The motor drive circuit 204C rotates the motor 30 in a direction in which the voltage signal becomes 0 (the difference is 0) based on the voltage signal input via the speed adjusting unit 206, and the motor 30 is connected to the voltage signal. Rotate at a rotation speed according to the size. The rotational speed of the motor 53 is detected by the tacho generator 53 and fed back to the motor drive circuit 204C.
[0042]
As a result, the master lens group 20 moves to the position of the position control signal generating means 50 or the macro position setting means 222 instructed by the switching means 224, and the moving speed is adjusted by the speed adjusting means 226.
The operation of the TV camera lens configured as described above will be described. First, when the changeover switch 224A of the macro switching unit 224 is turned off, the operation of the position control signal generating unit 50 becomes effective, and the voltage signal from the position control signal generating unit 50 is input to the control circuit 204. As a result, the master lens group 30 moves to the position set by the flange back adjustment knob 42 of the position control signal generating means 50. At this time, the tracking position (first limit position) (see FIG. 8) can be adjusted by adjusting the rotational position of the flange back adjustment knob 42.
[0043]
Next, when the changeover switch 224 </ b> A of the macro switching unit 224 is turned on, the operation of the macro position adjusting unit 220 becomes valid, and the voltage signal from the macro position adjusting unit 220 is input to the control circuit 204. As a result, the master lens group 30 moves to the position set by the macro position adjusting knob 230 of the macro position adjusting means 220. Then, by adjusting the rotation position of the macro position adjusting knob 230, the macro position of the master lens group 30 at the time of macro photography can be adjusted to a desired position, and the second operation in the blurring operation at the time of normal photography. The limit position (see FIG. 8) can be set to a desired position.
[0044]
When performing a blurring operation aiming at a special effect during normal shooting, the speed adjusting knob 234 of the speed adjusting unit 226 is adjusted, and the changeover switch 224A (macro changeover switch 232) of the macro switching unit 224 is turned on or off. Switch from to off. When the changeover switch 224A of the macro switching unit 224 is switched from OFF to ON, the master lens group 20 moves from the tracking position to the macro position, that is, from the first limit position at the speed set by the speed adjustment knob 234 of the speed adjustment unit 226. It moves to the position of the second limit. Conversely, when the changeover switch 224A is switched from on to off, the master lens group 20 moves from the macro position to the tracking position at the speed set by the speed adjustment knob 234 of the speed adjustment means 226.
[0045]
In this way, when performing a blurring operation aiming at a special effect, the macro position adjusting unit 222 adjusts a desired second limit position, and the speed adjusting unit 226 adjusts it to a desired moving speed, so that a switch ( The master lens group 20 can be moved at a desired speed and set in a desired blurring state by a simple on / off operation of the macro switch 232). Further, the master lens group 20 can be easily returned to the original tracking position by the on / off operation of the switch.
[0046]
【The invention's effect】
As described above, according to the TV camera lens of the present invention, the position of the master lens group whose position is controlled by the position control means is set as the limit position, and the movement of the master lens group is limited at the limit position during speed control. Therefore, the master lens group can be reliably stopped at a desired position while controlling the speed. In addition, since a limit position different from the limit position set by the position control means can be set, the master lens group is surely stopped at each limit position while controlling the speed between these two limit positions. be able to.
[Brief description of the drawings]
FIG. 1 is a side view of a lens for a television camera to which the present invention is applied.
FIG. 2 is a block diagram showing the configuration of a drive control system for a master lens group.
FIG. 3 is a block diagram showing another configuration of the drive control system of the master lens group.
FIG. 4 is a conceptual diagram showing a movement range of a master lens group during speed control.
FIG. 5 is a perspective view showing an operation state of a TV camera lens.
FIG. 6 is a block diagram showing another configuration of the drive control system of the master lens group.
FIG. 7 is a front view showing the appearance of the controller.
FIG. 8 is a conceptual diagram showing the movement range of the master lens group.
[Explanation of symbols]
10. Lens body
20 ... Master lens group
30 ... Motor
32 ... Potentiometer
42 ... Flange back adjustment knob
50. Position control signal generating means
52. Control circuit
60, 70 ... Controller for speed control
61. Speed control signal generating means
62 ... Position / speed switch
65 ... Limit circuit
66 ... Limit ON / OFF switch
67 ... Speed control range switch
68. First limit circuit
69 ... 1st limit ON / OFF switch
72. Limit signal generating means
74 ... Second limit ON / OFF switch
76 ... Second limit circuit
100 ... TV camera lens
120 ... TV camera

Claims (6)

Position control means for controlling the position of the movement of the master lens group disposed in the lens body;
Speed control means for speed controlling the movement of the master lens group;
A position / speed switching means for selecting any one of the position control means and the speed control means and enabling control by the selected control means;
Limit means for limiting the movement of the master lens group with the position controlled by the position control means as a limit position during speed control by the speed control means;
A lens for a TV camera, comprising:    The television camera lens according to claim 1, further comprising a limit canceling unit that cancels the limitation of the movement of the master lens group by the limit unit.   Select one of the first movement range from the limit position to the moving end in the forward direction and the second moving range from the limit position to the moving end in the backward direction, and the selected movement 3. The television camera lens according to claim 1, further comprising speed control range switching means that enables speed control of the master lens group within the range. Position control means for controlling the position of the movement of the master lens group disposed in the lens body;
Speed control means for speed controlling the movement of the master lens group;
A position / speed switching means for selecting any one of the position control means and the speed control means and enabling control by the selected control means;
Limit position setting means for setting a limit position for limiting movement of the master lens group;
A first limit unit that limits the movement of the master lens group using the position controlled by the position control unit as a first limit position during speed control by the speed control unit;
A second limit unit that limits the movement of the master lens group using the limit position set by the limit position setting unit as a second limit position during speed control by the speed control unit;
A lens for a TV camera, comprising:    5. The television camera lens according to claim 4, further comprising limit release means for releasing restriction of movement of the master lens group by at least one of the first and second limit means.    Select one of the first movement range from the first limit position to the forward movement end and the second movement range from the first limit position to the rearward movement end. 6. The television camera lens according to claim 4, further comprising speed control range switching means for enabling speed control of the master lens group within the selected movement range.

Images