JP3489128B2 - Lens device for television camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aspect ratio of 4: 3.
When shooting video displayed on a television receiver with a current size screen, and shooting video displayed on a television receiver with a landscape screen wider than the current size screen, zooming is performed. The present invention relates to a lens device for a television camera capable of photographing a field of view at an end position on the wide angle side of a lens in substantially the same state. 2. Description of the Related Art At present, a screen having an aspect ratio of 4: 3 is used as a screen of a television receiver. However, in recent years, the screen of the receiver has been enlarged due to improvement in image quality and the like. There is a tendency. For example, in the case of a large screen such as 50 inches or more, it is preferable to use a screen having an aspect ratio different from that of the current size screen because a screen that is horizontally long than the current size can provide a more realistic and powerful feeling. However, the aspect ratio of a high-definition television (HDTV) receiver is 16: 9. [0003] There is a difference in aspect ratio between a video projected on a television receiver having a current size screen and a video projected on a television receiver having a landscape screen. It is common to do. However, in a television camera using a solid-state imaging device such as a CCD, it is possible to generate a video signal having an arbitrary aspect ratio by electrically masking a part of the imaging area.
In view of this, a landscape image is shot using a solid-state imaging device having an imaging area (size ratio between width and height) suitable for shooting a video for a horizontally long screen television receiver. In this case, shooting is performed using the entire image receiving area, and when shooting an image for a television receiver having a screen of the current size, portions on both sides in the image sensing area of the solid-state image sensor are fixed. A configuration has been developed that switches the signal processing method in a video signal processing circuit so as to electrically mask over the width. With this configuration, one television camera can have multiple aspect ratios. Video signal is obtained. [0004] By the way, in the case where the field of view as shown in FIG. 4 is obtained by the lens device of the television camera, the field of view of the image for the landscape screen in the imaging means (see FIG. 4). Comparing the range of the image of the current size screen (the area shown by the dotted line in the figure) with the area of the current size screen (the area shown by the solid line inside) I can no longer do it. Of course, by performing the zooming operation, it is possible to make adjustments so that the viewing ranges on both screens match, but such adjustments cannot be made at the wide-angle end position. Further, at the time of shooting on the current size screen, it is possible to move the television camera away from the subject, but such an operation may not be performed in a small studio or the like. In short, even if 1
Even if it is possible to acquire video signals with multiple aspect ratios with one television camera, the fact that the field of view range at the end position on the wide-angle side changes due to the difference in aspect ratio is a factor in shooting. Not preferred. The present invention has been made in view of the above points, and an object of the present invention is to use a simple configuration to capture images having different aspect ratios at the wide-angle end position. An object of the present invention is to enable photographing in a state where a field of view is almost the same. In order to achieve the above object, the present invention provides a screen size having an aspect ratio of 16: 9.
Video to be displayed on a television receiver
Suitable camera body, screen size of 4: 3 aspect ratio
16: 9 screen display on a television camera receiver
To obtain a video signal with almost the same field of view as the video
In addition, a television camera that can switch the shooting mode
A lens device connected to the camera,
An end restrictor for restricting the movable range on the wide angle side,
Wide-angle end position adjusting means connected to the end restricting portion of
To obtain video signal for 4: 3 screen size
When switching to the appropriate shooting mode, the wide-angle
The zoom position on the wide-angle side of the zoom lens
The end restricting section is used to increase the movable range.
The feature is that the end position of the zoom lens can be changed . The aspect ratio of the screen of the current size in the television receiver is 4: 3 as described above.
On the other hand, the aspect ratio of the currently developed landscape screen is 16: 9. The operation of the zoom lens in the lens device is performed using the zoom rate. However, due to the relationship between the aberrations of the lens and restrictions on the mechanism of the lens device, etc.
The stroke range of this zoom lens is finite, and the end position is determined on the wide angle side and the telephoto side. At the end position on the wide-angle side, the lens device itself has a certain visual field range. However, in the image displayed on the screen of the current size, the image area is limited, so that the image displayed on the landscape screen is limited. , The visual field in the left-right direction is narrowed. However, when photographing an image for the current size screen, if the moving range to the wide angle side is set to be large, the photographing field of view at the end position on the wide angle side is set to be substantially the same as in the case of the landscape screen. It becomes possible. As described above, when the photographing mode is switched, the wide-angle end position is changed based on the wide-angle end position adjusting means by performing an interlocking operation or an independent operation. That is, the stroke end position on the wide-angle side of the zoom lens is more limited when capturing a video for a horizontally long screen than when capturing a video for a current size screen. As described above, by changing the end position on the wide-angle side, the imaging magnification in the lens device is slightly reduced, but the field of view becomes wider, so that the image of the horizontally long screen and the image of the current size screen are captured. An image in the same visual field range as at the time is obtained. Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a configuration of a television camera. In the figure, 1 is a lens device, and 2 is a camera body. In the lens device 1, a focus lens group 10, a zoom lens group 11, and a master lens group 12 are provided in this order from the subject side, and a lens group between the rear group of the zoom lens group 11 and the front group of the master lens group 12 is provided. Has an aperture 1
3 are provided. At an image forming position in the camera body 2, a solid-state image pickup device 1 such as a CCD is used as an image pickup means.
4 is provided, and the solid-state imaging device 14
An optical image of a subject obtained through the lens device 1 is formed and converted into an electric signal. FIG. 2 shows a circuit configuration for causing the zoom lens group 11 to perform a zooming operation. In the figure, reference numeral 20 denotes a zoom rate.
By operating 0, a zooming operation by the zoom lens group 11 can be performed. When the zoom rate 20 is operated, the resistance value of the potentiometer 20a at the zoom rate 20 changes, a voltage signal corresponding to the operation amount is output, and the output signal is amplified by the amplifier 21, and the output signal is amplified. The zoom lens drive motor 22 is driven at the set speed to perform the zooming operation. Further, a position detection potentiometer 23 is provided for detecting the position of the zoom lens group 11, and a signal from the position detection potentiometer 23 is input to an end limiting unit 24 that functions as a limiter for the zoom rate 20. It has become. The end limiter 24 includes a potentiometer 24a for setting an end, a comparator 24b for comparing an output signal of the potentiometer 24a with an output signal of the position detecting potentiometer 23, and a diode 24c.
The output signal of the end limiting unit 24 is
Are input to a comparator 25 provided on the output side of the. Accordingly, a signal relating to the current position of the zoom lens group 11 by the position detecting potentiometer 23 is input to the end restricting section 24, and the potentiometer 24
a is compared with a voltage value preset as an end position by the comparator 24b. When the zoom lens group 11 is displaced to the end position, a current flows through the diode 24c, and the zoom rate 20 is deviated. Even with the above operation, the drive signal to the zoom lens drive motor 22 is not supplied. Here, the end restriction unit 2
In FIG. 4, both the wide-angle side and the telephoto side end positions are set, but in the drawing, only the restriction part of the wide-angle side end position is shown, and with respect to the restriction part of the telephoto side end position, Its illustration is omitted. As shown in FIG. 3, the solid-state imaging device 14 has an imaging area with a ratio of 9 in the vertical direction to 16 in the horizontal direction. When driven so as to acquire, a video signal to be displayed on a screen having an aspect ratio of 16: 9, that is, a horizontally long screen, can be acquired. If the left and right portions are electrically masked by a predetermined width, a video signal to be displayed on a screen having an aspect ratio of 4: 3, that is, a current size screen can be obtained. The mode is switched between a method in which the video signal processing circuit is driven so as to obtain a video signal for a landscape screen and a method in which the video signal processing circuit is driven so as to obtain a video signal for a current size screen. It has a possible configuration. Therefore, by switching the shooting mode with a switch or other appropriate switching means, it is possible to shoot images on screens having different aspect ratios using one television camera. As described above, in the image shown in FIG. 4, the visual field range in the image for the current size screen is as follows.
The left and right sides are narrower than the visual field range in the image for the landscape screen. However, when shooting on the current size screen, the zoom lens group 11 of the lens device 1 is displaced,
If the field of view is as shown in FIG. 5, the image in the imaging area can be made to substantially match the image for the landscape screen in FIG. Therefore, when the mode for shooting the image for the landscape screen is selected, the image shown in FIG. 4 is obtained, and when the mode for shooting the image for the current size screen is selected, the mode shown in FIG. If the end position on the wide angle side of the zoom lens group 11 is changed so as to obtain an improved image, shooting can be performed in the same field of view at the end position on the wide angle side. For this purpose, the end position on the wide angle side can be selected by changing the set value of the potentiometer 24a in the end limiting section 24 according to the photographing mode. That is, the wide-angle end position adjusting means 30 is connected to the end restricting section 24, and the position of the output terminal T in the potentiometer 24a is changed by the wide-angle end position adjusting means 30 so that an image for a horizontally long screen is displayed. When the shooting mode is selected, the movable range of the zoom lens group 11 on the wide angle side is narrow, and when the mode for shooting an image for the current screen is selected, the movable range of the zoom lens group 11 on the wide angle side is widened. So that the end position can be changed. More specifically, for a landscape screen having an aspect ratio of 16: 9 and a current size screen having an aspect ratio of 4: 3, a wide-angle image is formed at a position where the former is 1 and the latter is 0.8. Set the side end position. With this configuration, when a mode for capturing a video for a landscape screen is selected when a subject is captured by the solid-state imaging device 14 mounted on the camera body 2, the wide-angle end position adjusting means is selected. By 30
The end position is set so that the movable range of the zoom lens group 11 on the wide-angle side is narrowed, and the movable range of the zoom lens group 11 is widened when a mode for capturing an image for the current screen is selected. Change the wide-angle end position. Therefore, when shooting at the end position on the wide-angle side, almost the same view range can be obtained for the video for the horizontally long screen and the video for the current size screen. Here, the wide-angle end position adjusting means 3
The selection of the end position by 0 can be performed in conjunction with the switching of the shooting mode, but it is possible to shoot in the shooting mode for the current size screen itself even if the viewing range is different. Therefore, it is better to select whether to change the end position on the wide angle side between the shooting mode for the landscape screen and the shooting mode for the current size screen in consideration of the photographer's preference etc. When the operation is convenient, the wide-angle end position adjusting means 30 can change the wide-angle end position independently of the switching of the photographing mode switching means. In the above-described embodiment, the wide-angle end position adjusting means is configured to be electrically adjustable, but the wide-angle end position of the zoom lens group 11 is regulated by mechanical means or the like. It is also possible to do so. As described above, according to the present invention, when forming a video signal of a television receiver having different aspect ratios, a zoom lens is arranged at an end position on the wide-angle side for photographing. In this case, the wide-angle end position adjustment means changes the wide-angle end position of the zoom lens between the two photographing modes. Can be substantially matched with the visual field range at the time of shooting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a main part configuration of a television camera showing one embodiment of the present invention. FIG. 2 is a circuit configuration diagram for performing a zooming operation by a zoom lens group. FIG. 3 is an operation explanatory diagram regarding an imaging area of a solid-state imaging device as an imaging unit. FIG. 4 is an operation explanatory diagram showing a visual field range of a lens device when acquiring a video signal for a landscape screen. FIG. 5 is an operation explanatory diagram showing a visual field range of a lens device when acquiring a video signal for a current size screen. [Description of Signs] 1 Lens device 2 Camera main body 13 Aperture 14 Solid-state imaging device 15 Field-of-view range correcting lens 20 Zoom rate 24 End limiting unit 30 Wide-angle end position adjusting means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 5/225 G02B 7/08 G02B 15/00

Claims (1)

(57) [Claims] [Claim 1] A screen having an aspect ratio of 16: 9.
Suitable for shooting video to be displayed on a television receiver
Camera with a screen size of 4: 3 aspect ratio
16: 9 screen size for television camera receiver
To obtain a video signal with almost the same field of view as
For TV cameras that can switch between shadow modes
A lens device to be connected, the lens device for limiting a movable range on the wide-angle side of the zoom lens.
And the wide-angle end connected to this end restriction
Video signal for 4: 3 screen size, including position adjusting means
When switching to the shooting mode suitable for acquiring
The wide-angle end position adjusting means controls the zoom lens.
End control so that the movable range on the wide-angle side
Changing the end position of the zoom lens by the limiter
A lens device for a television camera, wherein