JP2001036802A - Lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device capable of preventing an inconvenience that light quantity compensation is doubly performed by enabling on/off of the light quantity compensation to hold light quantity of a photographed image as constant by compensating diaphragm to a position to keep an F number before and after switching of magnification of an extender constant when the magnification is switched and performing no light quantity compensation in the lens device when the light quantity compensation is performed by the transmitting side of a control signal of the diaphragm. SOLUTION: The light quantity is made to be constant when the magnification of the extender 24 is switched by compensating a diaphragm position according to the magnification of the extender 24 for an iris control signal to be provided from a camera control part 16, etc., of a television camera 12 when a compensation selecting switch 30 is on by a lens control part 14 of the lens device 10. No light quantity compensation is performed when the compensation selecting switch 30 is off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens device,
In particular, the present invention relates to a lens device that automatically adjusts an aperture position when a photographing magnification is converted by an extender lens or a ratio converter lens to maintain the brightness of a photographed image constant.

[0002]

2. Description of the Related Art In recent years, in the field of television cameras for broadcasting and the like, cameras capable of selectively switching between an aspect ratio of 4: 3 and an aspect ratio of 16: 9 have been put to practical use. In this type of switchable camera, for example,
When a 16: 9 CCD element is used for the image pickup surface and the aspect ratio is set to 4: 3, the right and left partial areas of the CCD element are not used, and only the central area having the aspect ratio of 4: 3 is used. I'm trying to use Therefore, when the aspect ratio is set to 4: 3, the angle of view is reduced by about 20%, and the image projected on the screen is apparently shifted to the telephoto side.

In order to solve such a problem, when a camera is used with an aspect ratio of 4: 3, a ratio converter of about 0.8 times (hereinafter simply referred to as 0.8 times) is provided on a photographing optical path. There is known a lens device equipped with a ratio converter that changes the image size by inserting a lens and makes the shooting angle of view substantially the same at an aspect ratio of 16: 9 and an aspect ratio of 4: 3.

Along with the above-mentioned ratio converter lens, for example, a 1 × and 2 × zoom lens (extender lens) is arranged on a disk-shaped turret, and these lenses are placed on a photographing optical path by rotating the turret. It is inserted and removed and the photographing magnification is 0.8 times, 1 time, and 2 times (approximately 1 time and 1.2 times when using at 4: 3 aspect ratio).
A lens device equipped with an extender that is capable of switching to a magnification ratio of 2.4 × and that has a function of a ratio converter and a function of switching a shooting magnification to a high magnification is also known. In this specification, a ratio converter lens is also treated as a kind of extender lens unless otherwise specified.

In the above-described lens apparatus equipped with an extender, when the magnification of the extender (magnification of the extender lens inserted on the photographing optical path) is switched, the focal length of the photographing optical system changes, and the photographed image is changed. Changes in brightness. For this reason, there is known a lens device which automatically corrects the aperture position (aperture diameter) when the magnification of the extender is switched to make the F-number constant and corrects the amount of light so that the brightness of a captured image does not change. .

[0006]

However, conventionally,
In the case where the lens device controls the aperture based on an iris control signal provided from outside such as a television camera, the transmitting side of the iris control signal detects the magnification of the extender, and according to the magnification of the extender, In some cases, such light quantity correction is performed by the transmitting side of the iris control signal. In such a case, if the light amount correction is also performed on the lens device side, the light amount correction is performed on both the transmission side of the iris control signal and the lens device side, so that there is a problem that appropriate light amount correction cannot be performed. Had occurred.

The present invention has been made in view of such circumstances, and the content of the aperture control based on the iris control signal depends on whether or not the transmitting side of the iris control signal performs light amount correction in accordance with the magnification of the extender. An object of the present invention is to provide a lens device capable of performing appropriate light amount correction by switching.

[0008]

In order to achieve the above object, the present invention provides a photographing magnification of a photographing lens by inserting and removing a ratio converter lens corresponding to an aspect ratio of a camera on a photographing optical path of the photographing lens. A lens apparatus that switches between a standard magnification and a high magnification or a low magnification by changing an imaging magnification of the imaging lens to a standard magnification by switching an imaging lens to a standard magnification corresponding to a predetermined aspect ratio and inserting and removing an extender lens on an imaging optical path of the imaging lens. An iris control signal acquisition unit that acquires an iris control signal that specifies an aperture position; a selection unit that selects whether to perform light amount correction; and a case where the light amount correction is selected by the selection unit. The shooting magnification is increased by inserting and removing the extender lens or the ratio converter lens on the shooting optical path. When the magnification is set to a value other than the normal reference, the aperture position becomes the same as the F-number when the aperture is set to the aperture position specified by the iris control signal when the shooting magnification is set to the correction reference magnification. An aperture control unit that sets an aperture and sets an aperture at an aperture position specified by the iris control signal when the selection unit selects not to perform light amount correction. And

According to the present invention, since there is provided means for selecting whether or not to perform light quantity correction in accordance with the magnification of the extender lens or the ratio converter lens which is inserted into and removed from the photographing optical path of the photographing lens. When performing aperture control based on the iris control signal given by the iris control signal, when performing light quantity correction on the iris control signal transmission side, the lens apparatus does not perform light quantity correction, When not performed, by performing the light amount correction in the lens device, it becomes possible to appropriately perform the light amount correction regardless of whether the transmitting side of the iris control signal performs the light amount correction.

[0010] Further, whether or not to perform light quantity correction in the lens device can be selected separately when the extender lens is inserted and removed and when the ratio converter lens is inserted and removed, so that the iris control signal can be selected. Even when the light amount correction performed on the transmission side is performed for only one of the insertion and removal of the extender lens of the lens device and the insertion and removal of the ratio converter lens, the light amount correction for only the other is performed by the lens device. This makes it possible to perform appropriate light amount correction in accordance with the mode of light amount correction performed by the transmitting side of the iris control signal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a lens device according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of components relating to aperture control and extender control in a lens device mounted on a television camera. As shown in FIG. 1, the lens device 10 is electrically connected to the television camera 12 so that a predetermined signal can be exchanged.

The lens device 10 includes an extender 24.
A lens control unit 14 that controls the extender 24 and the aperture 28 based on a predetermined control signal, and an extender driving unit 2 that drives the extender 24 according to an instruction from the lens control unit 14.
2, and an iris driving unit 26 for driving the diaphragm in accordance with an instruction from the lens control unit 14. The lens device 10 includes optical members such as a zoom lens and a focus lens (not shown) in addition to the extender 24 and the aperture 28.

A controller having a remote iris control signal generator 18 mounted thereon and an extender controller 20 are connected to the lens device 10. The lens control unit 14 is connected to the remote iris control signal generator 18.
, An extender switching signal output from the extender controller 20, and the like.

Further, the lens device 10 is provided with a correction selection switch 30 which allows the user to select whether or not to perform light quantity correction described later.

On the other hand, the television camera 12 is, for example, of a type that can switch the aspect ratio of a photographed image between 16: 9 and 4: 3, and has a camera control unit 16 mounted thereon. ing. The camera control unit 16 performs various signal processing such as capturing an image of a subject formed by the lens device 10 with an image sensor and generating the image as a video signal, and also performs a currently set aspect ratio (a shooting mode). ), And outputs an 16: 9/4: 3 switching signal (hereinafter referred to as a photographing mode switching signal) and an iris control signal for instructing the lens device 10 on the aperture position.

The operation of the lens device 10 configured as described above will be described. When the lens controller 14 receives an extender switching signal from the extender controller 20, the lens controller 14 drives the extender driver 22 based on the extender switching signal. Then, the extender 24 is controlled to switch the magnification of the extender lens to be inserted into the photographing optical path of the lens device 10. As shown in FIG. 2, the extender 24 has a disk-shaped turret 50, a 1-fold extender lens EXT1, a 2-fold extender lens EXT2, and about 0.8 times (hereinafter simply referred to as 0.8 times). Extender lens (ratio converter lens) C is arranged, and the turret 5
By rotating 0, the type of extender lens to be inserted on the photographing optical path is switched,
Can be instantaneously switched to 1, 2, or 0.8 times. In particular, a 1 × extender lens EXT1 and a 0.8 × ratio converter lens R.R. C
Means that the aspect ratio of the TV camera 12 is 1
At the time of 6: 9 and 4: 3, it is inserted on the photographing optical path to photograph a standard angle of view. At this time, the magnification (1, 0.8 times) of the extender 24 depends on each aspect ratio (1.
6: 9, 4: 3). Extender 24 when the aspect ratio is 16: 9 and 4: 3
Is set to the standard magnification, the same angle of view can be obtained if the position of the zoom lens (not shown) is the same.

The ratio converter lens R. C can be used as a 0.8-fold extender lens at an aspect ratio of 16: 9, and the extender lens EXT1 is used as a 1.25-fold extender lens at an aspect ratio of 4: 3. Is also possible. Also, a 1 × extender lens EXT1 and a 0.8 × ratio converter lens R.R. Switching to C can be automatically performed based on a shooting mode switching signal provided from the camera control unit 16.

When the lens control unit 14 receives an iris control signal from the remote iris control signal generator 18 or the camera control unit 16 of the television camera 12,
The iris drive unit 26 is driven based on the iris control signal to control the position (diameter) of the aperture 28. At this time, it is detected whether the correction selection switch 30 is on or off. If the correction selection switch 30 is on, a light amount correction process described later is performed. Don't do it. When the light amount correction process is not performed, the lens control unit 14 sets the aperture as it is at the aperture position specified by the iris control signal. A predetermined switch determines which of the iris control signals from the iris control signal supplied from the remote iris control signal generator 18 and the iris control signal supplied from the camera control unit 16 of the television camera 12 is used. It is also possible to make the selection possible, and it is also possible to determine in advance which of them should be prioritized.

In the light quantity correction, the aperture position is corrected so that the brightness of the photographed image does not fluctuate when the magnification of the extender 24 is switched, so that the F number of the photographing lens becomes the same before and after the switching. . In particular, the correction of the light amount performed here is not performed by correcting the aperture position indicated by the value of the iris control signal (shifting the aperture position by a predetermined amount) only when the magnification of the extender 24 is switched, but by using a lens. The lens control unit 14 constantly corrects the aperture position indicated by the iris control signal given to the control unit 14 by shifting the aperture position by a predetermined amount according to the magnification of the extender 24,
When the magnification of the extender 24 is switched, the correction is switched to a correction corresponding to the magnification, and as a result, the F number is the same before and after the magnification of the extender 24 is switched. Note that the lens controller 14 acquires the currently set magnification of the extender 24 from the extender position information given from a predetermined detector of the extender 24.

The correction selection switch 30 is provided in consideration of the fact that such light amount correction may be performed on the transmitting side of the iris control signal, that is, on the television camera 12 or the remote iris control signal generator 18. By turning off the correction selection switch 30 when the transmitting side of the iris control signal performs the light amount correction, the light amount correction on the transmitting side and the light amount correction in the lens device 10 are performed in an overlapping manner. Can be avoided.

FIGS. 3 and 4 are diagrams for explaining the content of light quantity correction. FIG. 3 shows that the shooting mode of the TV camera 12 is 1
In the case of 6: 9, the correction contents when the magnification of the extender 24, which is the reference (correction reference) of the light amount correction, is set to 1 are shown, and the aperture position (aperture diameter) shown in FIG. Of the iris control signal (voltage) for instructing the aperture position with respect to the movable ranges A and B of FIG.
((B) in the figure) and a 1 × extender lens EXT
1, 2x extender lens EXT2 and ratio converter lens R.R. The range of the F-number when C is inserted on the photographing optical path, respectively (FIGS. (C), (d),
FIG.

As shown in FIGS. 3A and 3B, the value of the iris control signal is VA for the movable range A to B of the aperture position.
To VB. Further, when the magnification of the extender 24 is 1, the F-number is 1.4 to 1.4 with respect to the movable range A to B of the aperture position as shown in FIG.
It changes in the range of 16. Note that the numerical range of the F number is an example, and is not limited to this.

On the other hand, when the magnification of the extender 24 is 2 times, the F number shifts in a direction to become larger as a whole with respect to the movable ranges A and B of the aperture position as shown in FIG. F-number range 1.4 shown in FIG.
The range that is the same as that of to 16 is shifted to the left in the figure. Also, when the magnification of the extender 24 is 0.8, the F-number shifts in a direction to become smaller as a whole with respect to the movable range A to B of the aperture position as shown in FIG. ) Is shifted to the right in the figure. Therefore, when the aperture is set at the position indicated by the value of the iris control signal, the F number changes depending on the magnification of the extender, and the brightness of the captured image changes when the magnification of the extender is switched.

Therefore, the lens control unit 14 sets the aspect ratio of the television camera 12 to 16:
If it is determined to be 9, the magnification of the extender 24 is 1
When the magnification of the extender 24 is another magnification, the extender 2 (standard magnification) is used as the correction reference.
The iris control signal is corrected by signal correction processing so as to match the F number when the magnification of 4 is 1 and the aperture is set at the correction position. That is, when the aspect ratio of the TV camera 12 is 16: 9, the extender 2
When the magnification of 4 is 1x (standard magnification),
The aperture is set as it is at the aperture position indicated by the value of the iris control signal. When the magnification of the extender 24 is doubled based on the F number at this time, the shift amount of the F number range 1.4 to 16, that is, the offset amount V02 shown in FIG. The value is subtracted from the value, and the aperture is set at the position indicated by the value obtained thereby. When the aperture is set at the same position when the extender 24 is 1x and when the extender is 2x, the F-number when the extender 24 is 2x is larger than the F-number when the extender 24 is 1x. Double. Therefore, as described above, the aperture position is set to the offset amount V02.
The process of shifting by an amount is performed by 1/2 of the F number at the aperture position indicated by the iris control signal, when the F number at the time of assuming the magnification of the extender 24 is 1 (FIG. 3C). This is equivalent to a process of shifting the aperture position to a position where the aperture is doubled.

Thus, when the values of the iris control signals are the same, the F-number becomes the same when the extender 24 is one time and when the extender 24 is two times as shown by the dotted lines a and b in FIG. The brightness of the captured image is kept constant when switching between double and double.

When the aspect ratio is 16: 9, the ratio converter lens R.P. C can also be used as a 0.8x extender lens, and in this case also, light amount correction is possible. When the magnification of the extender 24 is 0.8, the amount by which the range of F number 1.4 to 16 shifts, that is, the offset amount V01 shown in the figure is added to the value of the iris control signal, and the value obtained by this is added to the value of the iris control signal. Set the aperture at the position shown. In addition, extender 24
When the aperture is set at the same position when the magnification is 1 × and when the magnification is 0.8 ×, the F-number when the extender 24 is 0.8 × is larger than the F-number when the extender is 1 ×. Since the magnification becomes eight times, the process of shifting the aperture position by the offset amount V01 as described above is based on the iris control when the magnification of the extender 24 is assumed to be 1 (FIG. 3 (c)). This is equivalent to a process of shifting the aperture position to a position that is 1 / 0.8 times the F number at the aperture position indicated by the signal.

Thus, when the values of the iris control signals are the same, the F-number becomes the same when the extender 24 is 1 and 0.8 times as shown by the dotted lines a and c in FIG. Is switched between 1 × and 0.8 ×, the brightness of the captured image is kept constant.

FIG. 4 shows the correction contents when the magnification of the extender 24, which is the reference (correction reference) of the light amount correction, is set to 0.8 when the shooting mode of the television camera 12 is 4: 3. And a range VA to VB of the value of the iris control signal for designating the diaphragm position (FIG. (B)) with respect to the movable range A to B of the diaphragm position (diaphragm diameter) shown in FIG. 1x extender lens EXT1, 2
Times extender lens EXT2 and ratio converter lens R.R. The range of the F-number when C is inserted on the photographing optical path, respectively (FIGS. (C), (d),
FIG.

When the lens control unit 14 determines that the aspect ratio is 4: 3 based on the shooting mode switching signal given from the camera control unit 16 of the television camera 12,
When the magnification of the extender 24 is the standard magnification of 0.8, the correction standard is used. When the magnification of the extender 24 is another magnification, the extender 24 is used.
The iris control signal is corrected by a signal correction process so as to match the F-number when the magnification is 0.8 times, and the aperture is set at the correction position. That is, when the aspect ratio of the TV camera 12 is 4: 3, the extender 2
When the magnification of No. 4 is 0.8 times (standard magnification), the aperture is set as it is at the aperture position indicated by the value of the iris control signal. Therefore, as shown in FIG.
The number shifts between FA (<1.4) and Fb (> 11). Based on the F number at this time, when the magnification of the extender 24 is 2 times,
The shift amount of the number range 1.4 to 16, that is, the offset amount V12 shown in the figure is subtracted from the value of the iris control signal, and the aperture is set at the position indicated by the obtained value. When the aperture is set at the same position when the extender 24 is 0.8 times and when the extender is 2 times, the F-number when the extender 24 is 2 times is
The F number becomes 2.4 times that of the F number when 4 is 0.8 times. Therefore, as described above, the aperture position is set to the offset amount V12.
The process of shifting by the amount is performed by the F-number when the magnification of the extender 24 is assumed to be 0.8 times (FIG. 4E).
, The F at the aperture position indicated by the iris control signal
This is equivalent to a process of shifting the aperture position to a position that is 0.8 / 2 with respect to the number.

Thus, when the value of the iris control signal is the same, the F number becomes the same when the extender 24 is 0.8 times and when the extender 24 is twice as shown by the dotted lines b and c in FIG. Is switched between 0.8 times and 2 times, the brightness of the captured image is kept constant.

When the aspect ratio of the TV camera 12 is 4: 3 and the magnification of the extender 24 is 1, the F-number range 1.4 to 16 shifts, that is, the offset shown in FIG. The amount V11 is subtracted from the value of the iris control signal, and the aperture is set at the position indicated by the value obtained thereby. When the aperture is set at the same position when the extender 24 is 0.8 times and when it is 1 time, the F number when the extender 24 is 1 times is the F number when the extender 24 is 0.8 times. It becomes 1.25 times the number. Therefore, as described above, the process of shifting the aperture position by the offset amount V11 is as follows.
Referring to the F number (FIG. 4E) when the magnification of the extender 24 is assumed to be 0.8 times, the position becomes 0.8 times the F number at the aperture position indicated by the iris control signal. This is equivalent to a process of shifting the aperture position.

Thus, when the values of the iris control signals are the same, the F number becomes the same when the extender 24 is 0.8 times and when the extender 24 is 1 time, as shown by the dotted lines a and c in FIG. Is switched between 0.8 × and 1 ×, the brightness of the captured image is kept constant.

As described above, in the above-described embodiment, the magnification of the extender 24, which is the correction reference for the light amount correction, is set to 1 and 0.8 when the aspect ratio of the television camera 12 is 16: 9 and 4: 3. Although the switching is performed, it is not always necessary to switch the correction reference according to the aspect ratio. For example, even when the aspect ratio is 4: 3, the correction criterion is 16: 9.
As in the case of (1), the correction reference may be multiplied by one.

In the above embodiment, when the user selects whether or not to perform light quantity correction, the correction reference is automatically set by a shooting mode switching signal provided from the television camera 12, but the correction reference is It may be set by the user.

In the above embodiment, whether or not to perform the light amount correction processing for all magnifications other than the correction reference of the extender 24 is selected by turning on and off the correction selection switch 30. However, the transmitting side of the iris control signal may correct the light amount for a part of the magnification of the extender 24, but may not perform the light amount correction for the other magnifications. It may be possible to select whether or not to perform the light amount correction processing.

In the above embodiment, the magnification of the extender 24 can be switched between 0.8 times, 1 time, and 2 times. However, the magnification of the extender 24 is not limited to this. Naturally, it is also possible to switch to the magnification, and in such a case, the present invention can be applied similarly to the above embodiment.

[0038]

As described above, according to the lens apparatus of the present invention, whether or not to perform light quantity correction according to the magnification of the extender lens or the ratio converter lens inserted into and removed from the photographing optical path of the photographing lens is determined. In the case where aperture control is performed based on an iris control signal externally supplied from a camera or the like, when performing light amount correction on the transmission side of the iris control signal, the lens device does not perform light amount correction. When the light amount correction is not performed on the transmission side of the iris control signal, appropriate light amount correction is performed by performing the light amount correction in the lens device regardless of whether the transmission side of the iris control signal performs the light amount correction. become able to.

Also, whether or not to perform light quantity correction in the lens device can be selected separately when the extender lens is inserted and removed and when the ratio converter lens is inserted and removed, so that the iris control signal Even when the light amount correction performed on the transmission side is performed for only one of the insertion and removal of the extender lens of the lens device and the insertion and removal of the ratio converter lens, the light amount correction for only the other is performed by the lens device. This makes it possible to perform appropriate light amount correction in accordance with the mode of light amount correction performed by the transmitting side of the iris control signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of components related to aperture control and extender control in a lens device mounted on a television camera.

FIG. 2 is a configuration diagram showing a configuration of a turret of an extender.

FIG. 3 is an explanatory diagram showing the content of light amount correction when a correction reference is set to 0.8 times.

FIG. 4 is an explanatory diagram showing the content of light amount correction when the correction reference is set to 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Lens device, 12 ... TV camera, 14 ... Lens control part, 16 ... Camera control part, 18 ... Remote iris control signal generator, 20 ... Extender controller,
22 ... extender drive, 24 ... extender,
26: iris drive unit, 28: diaphragm

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H002 CC21 EB11 FB21 FB24 FB36 HA07 HA11 JA08 5C022 AB12 AB31 AB66 AC54 AC55 AC56 AC69

Claims (2)

[Claims] 1. A photographing magnification of a photographing lens is switched to a standard magnification corresponding to a predetermined aspect ratio by inserting and removing a ratio converter lens corresponding to an aspect ratio of a camera on a photographing optical path of the photographing lens. An iris control signal for acquiring an iris control signal for designating an aperture position in a lens device that switches an imaging magnification of the imaging lens between standard and high or low magnification by inserting and removing an extender lens on an imaging optical path of the imaging lens. Acquiring means; selecting means for selecting whether or not to perform light quantity correction; and when the selecting means has selected to perform light quantity correction, the extender lens or the ratio converter lens is inserted into the photographing optical path. If the shooting magnification is set to a magnification other than the correction standard due to When the magnification is set as the correction reference magnification, the aperture is set to the same aperture position as the F-number when the aperture is set to the aperture position specified by the iris control signal, and the light amount is corrected by the selection unit. And a diaphragm control unit for setting a diaphragm at a diaphragm position designated by the iris control signal when no lens is selected. 2. The image forming apparatus according to claim 1, wherein the selecting unit selects whether or not to perform the light amount correction with respect to a change in photographing magnification due to the insertion and removal of the extender lens, and performs photographing by inserting and removing the ratio converter. 2. The lens apparatus according to claim 1, wherein whether or not to perform the light amount correction for the conversion of magnification can be separately selected.