JPS63131112A - Video camera photographing mechanism - Google Patents

Abstract

PURPOSE:To vary a zoom ratio automatically according to range measurement information from an AF mechanism and to take a photograph to invariably constant image plane size by controlling a motor-driven zooming mechanism according to the arithmetic processing output of the extension quantity of a zoom lens. CONSTITUTION:Range measurement information on focusing from the AF mechanism 1 is supplied to an arithmetic processing part 2 and a CPU 22 detects the corresponding angle theta of rotation of a zoom motor 32 in a ROM 21 according to the zoom ratio calculated by the motor-driven zoom mechanism 3 and the zoom lens 33 moves along the optical axis. Then a switching means 4 is set in normal photographic mode and then a zoom lever is operated to set the image plane side of a subject in a finder optionally. Then, the switching means 4 is switched to a zoom automatic mode, and then the zoom ratio corresponding to the range measurement information from the AF mechanism 1 based upon the image plane size set value is calculated and the zoom motor 32 is controlled automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shooting mechanism of a video camera, and more specifically, it performs zooming according to distance measurement information obtained from an autofocus mechanism, and constantly maintains a large screen. The present invention relates to a video camera shooting mechanism that controls the angle of view so that the angle of view is constant.

(Prior Art) Conventionally, there have been cases in which it has been desired to attach a zoom lens to a video camera or the like to constantly photograph a moving subject on a constant screen size. For example, when photographing the facial expressions of a moving athlete at a sports competition, etc., the main subject's face is always the same size on the screen no matter how far away from the camera it is or when it approaches. This is the case when you want to do it (below,
In the present invention, the function in which the above-mentioned special photography is automatically controlled is referred to as an auto-zoom function). In order to perform such special photography, the photographer needs to adjust the focus and operate the zoom lever to take the picture.

(Problems to be Solved by the Invention) However, it is difficult to perform the two operations of focus adjustment and zooming at the same time, and the shutter opportunity for this purpose may be lost. In particular, when performing the above-mentioned special photography with a video camera that continuously records a series of movements,
Even if autofocus (AP) i-framework eliminates the need for focusing, the zoom lever must be constantly operated in accordance with the movement of the subject to maintain a high-quality image. It's difficult to do.

The purpose of the present invention was achieved based on the above circumstances, and
To provide a photographing mechanism of a video camera capable of automatically changing a zoom ratio (angle of view) according to distance measurement information from an AP mechanism and photographing a subject while keeping the screen size constant at all times. It is in.

(Means for Solving the Problems) That is, the above object of the present invention is to provide a photographing mode switching means for switching between a normal photographing mode in which photographing is performed by manual or electric zoom operation and a photographing mode in which photographing is performed in zoom auto mode; an autofocus mechanism, an electric zoom mechanism, a screen size setting means that operates in the normal shooting mode and can arbitrarily set the screen size of the main subject to be photographed by operating a zoom lever or an electric zoom switch; and the screen size setting means. After setting, switch from normal shooting mode to zoom auto mode, capture the main subject in the viewfinder, and change the screen mode of the main subject to the set screen size according to distance measurement information from the autofocus mechanism. includes a calculation processing unit that calculates the amount of extension of the zoom lens to match the set value;
This is achieved by a photographing mechanism of a video camera, characterized in that the electric zoom mechanism is controlled by the output of the arithmetic processing section.

(Function) The present invention determines the size of the main subject on the screen through initial settings, and then automatically adjusts the focus when the main subject moves according to the distance from the camera. Distance information is detected from the AFi configuration, and the zoom ratio is changed based on this distance measurement information so that the size of the subject on the screen becomes approximately constant.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing one embodiment of a photographing mechanism of a video camera according to the present invention.

In FIG. 1, the photographing mechanism of the video camera of the present invention is as follows:
Broadly speaking, it consists of four components: an F mechanism 1, an arithmetic processing section 2, an electric zoom mechanism 3, and a photographing mode switching means 4.

In the AP mechanism 1, the focus detection method is obtained by a shift detection method. The lens detection method is conventionally well known, and its configuration is not directly related to the present invention.
Although I will not go into details, the system detects the deviation of the light flux that has passed through different parts on the left and right sides of the photographic lens and adjusts the focus.After the light flux that has passed through the photographic lens forms an image once,
It utilizes the fact that by passing through a relay lens, two images are formed at a certain distance apart. If the positional relationship between the relay lens and the imaging plane of the two images is fixed, the distance between the two images in the focused state will always be constant, and at the front focus, the distance between the two images will be the same in the focused state. On the other hand, the distance between images is longer in the rear bin, so the amount of defocus and its direction are detected.However, the present invention is not limited to this detection method, and can be applied to other detection methods. For example, a method known as a blur detection method may be used.

In any case, the present invention receives distance measurement information at the time of focusing as a digital value from the AP mechanism.

The arithmetic processing section 2 further includes a recording section 21, a control section 22, and a processing section 23.

The recording section 21 is provided with a ROM, and records the relationship between the angle of view and the amount of extension of the zoom lens, which will be described below.

In a zoom lens, the lens extension ratio generally changes when the focal length changes. Here, the relationship between the angle of view (z), which is relative to the focal length, and the rotation angle (θ) of the zoom motor, which corresponds to the lens extension ratio, also changes, and is expressed by the relational expression θ = f (z), -1G is expressed by the relationship shown in FIG.

Therefore, the above-mentioned relationship determined by the lens design is stored in the ROM.

The control unit 22 includes a control processor (CPU)
The ROM information is read out and arithmetic processing, which will be described later, is performed.

The processing section 23 is provided by a control processor, and manages a calculation system 23a and a drive system 23b.

The calculation system 23a calculates the angle of view (d) from the distance (d) to the subject obtained by the AP mechanism 1 as ranging information.
z).

This calculation is performed based on the relational expression. Here α is a coefficient,
The present invention corresponds to a screen size setting value that is arbitrarily initialized.

That is, the present invention uses the screen size setting value, which is first determined by the photographer by framing, as a reference, and performs a zoom operation in the direction of always obtaining the same size screen even if the distance from the camera to the main subject changes. As is clear from Fig. 3, the above relational expression is based on the distance (
d) and the angle of view (z) are in an inversely proportional relationship.

The control unit 22 detects the rotation angle (θ) of the corresponding zoom motor from the ROM based on the angle of view (z) calculated by the processing unit 23, and instructs the drive system 23b.

The electric zoom mechanism 3 includes a motor driver 31, a motor 32, and a zoom lens 33.
Control 1. Further, the motor 32 is rotated based on the rotation angle (θ) of the zoom motor to move the zoom lens 33 along the optical axis.

The photographing mode switching means 4 has a normal photographing mode in which photographing is performed by manual or electric zoom operation, and an auto zoom function, that is, the angle of view is changed according to distance measurement information from the A/F mechanism 1 that changes from time to time depending on the movement of the main subject. Switch between shooting modes that change and shoot.

When taking pictures using the auto zoom function, the photographer first sets the closest mode switching means 4 to the normal shooting mode, then operates the zoom lever or electric zoom switch to set the screen size of the main subject using the screen size setting means. is arbitrarily set in the viewfinder.Next, by switching the shooting mode switching means 4 to the zoom auto mode and capturing the main subject in the viewfinder, distance measurement from the AP mechanism based on the screen size setting value is performed. The angle of view according to the information is calculated, and the zoom motor is automatically controlled.As a result, photography is performed using the auto zoom function.

Furthermore, when the normal shooting mode is selected, normal shooting operations using a video camera with a zoom lens can be performed, and the angle of view can be selected according to the distance by operating the zoom lever or electric zoom switch.

(Effects of the Invention) As described above, the video camera photographing mechanism of the present invention is equipped with an AF mechanism, and the angle of view of the zoom lens is automatically controlled according to distance measurement information obtained from the AP mechanism. Therefore, you can always take pictures with the preset screen size.

Moreover, since a series of photographing operations for achieving the above-mentioned purpose are automated, the photographer can enjoy various special photographing without placing any burden on the photographer.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram explaining one embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the focal length and angle of view of a zoom lens, and the rotation angle of the zoom motor, and Fig. 3 is a diagram showing the angle of view. FIG. 3 is a diagram illustrating the relationship between the distance to the main photographic subject and the distance to the main photographic subject. ■...-autofocus mechanism, 2-arithmetic processing unit, 3-
- Electric zoom mechanism, 4-.- Shooting mode switching means. Figure 2 Figure 3

Claims (1)

[Claims] 1) A photographing mode switching means for switching between a normal photographing mode in which photographing is performed by manual or electric zoom operation and a photographing mode in which photographing is performed in zoom auto mode, an autofocus mechanism, an electric zoom mechanism, and a normal photographing mode. A screen size setting means that operates in the shooting mode and allows you to arbitrarily set the screen size of the main subject to be photographed by operating the zoom lever or electric zoom switch, and after setting the screen size setting means, it is possible to switch from the normal shooting mode to the zoom auto mode. By capturing the main subject in the viewfinder, the zoom lens adjusts the screen size of the main subject to match the set screen size setting value according to distance measurement information from the autofocus mechanism. 1. A video camera photographing mechanism, comprising: an arithmetic processing section that calculates a feed-out amount, and the electric zoom mechanism is controlled by an output of the arithmetic processing section. 2) The video camera photographing mechanism according to claim 1, wherein the angle of view determined by the amount of extension of the zoom lens is controlled to be inversely proportional to distance measurement information.