JPH08262305A - Power varying method for camera and lens system - Google Patents

Abstract

PURPOSE: To provide a camera capable of performing delicate power varying operation and smoothly varying power. CONSTITUTION: The power varying speed of a lens system having a variable power lens group 102 is controlled in accordance with the value of voltage generated in a zoom switch 123. In such a case, relation between the value of voltage and the power varying speed is made non-linear characteristic, for example, like a logarithmic curve. Thus, the delicate power varying operation is executed. By setting plural kinds of non-linear characteristic for the focal distance of the lens system, the power is smoothly varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera equipped with a zoom lens using a variable power lens and a variable focus lens,
In particular, it relates to variable power control of the lens.

[0002]

2. Description of the Related Art FIG. 6 is an explanatory diagram of a variable power operation which has been conventionally used. (A) is a zoom switch, which is made of a variable resistor so that a voltage corresponding to the rotation angle of the operating member is output. Variable speed zooming is performed according to this output voltage.

(B) shows the relationship between the voltage and the variable speed zoom speed. In the vicinity of the intermediate 2.5 V of the output voltage, the variable-magnification operation is stopped. When it is smaller than that value, the variable-magnification operation is performed in the wide direction. The lower the voltage, the higher the speed, and the higher the voltage, the lower the speed. When the voltage is higher than the stop voltage, the zooming operation is performed in the tele direction. The higher the voltage, the higher the speed, and the lower the voltage, the lower the speed. Wide direction,
In both tele directions, the voltage and the variable speed have a linear relationship.

[0004]

However, if the relationship between the voltage and the variable speed is linear, delicate operation is difficult and the human sense feels that the speed suddenly increases.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a zooming method for a camera and a lens system, which enables easy delicate zooming operation and smooth zooming. To do.

[0006]

In order to achieve the above-mentioned object, in the present invention, the camera has the following (1), (2) and (3).
And the zooming method of the lens system is configured as in (4) below.

(1) A lens system having a variable power lens, instructing means for instructing a variable speed by a value of an electric variable, and a variable characteristic in which a relation between the value of the electric variable and the variable speed has a non-linear characteristic. A camera equipped with a driving means for a double lens.

(2) The camera according to (1), wherein the non-linear characteristic is a logarithmic curve type characteristic.

(3) The non-linear characteristic is a plurality of characteristics set with respect to the focal length of the lens system.
The listed camera.

(4) A zooming method for a lens system in which the relationship between the movement of the operating member for instructing the zooming speed of the lens system and the zooming speed is a nonlinear characteristic.

[0011]

With the configurations (1), (2), and (3) described above, the variable speed varies with the value of the electrical variable in accordance with the nonlinear characteristic. With the configuration (3), the zooming speed changes according to a plurality of nonlinear characteristics set with respect to the focal length of the lens system. With the configuration of (4), the zooming speed changes with a non-linear characteristic with respect to the movement of the operating member.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 is a block diagram showing the configuration of the "video camera" which is the first embodiment. In FIG. 1, 101,
Reference numerals 102, 103, 104 and 105 are elements constituting an inner focus type lens system, respectively, and are a front lens group which is a fixed first lens group and a second lens group (hereinafter , A variable power lens), a diaphragm, a fixed third lens group, and a fourth lens group (hereinafter referred to as a focus lens) having both a competition (focus correction) function and a focusing function. The image light transmitted through this lens system is imaged on the surface of the image pickup element 106 and converted into an image signal by photoelectric conversion. Reference numeral 107 is an amplifier (or impedance converter), and 108 is a camera signal processing circuit. The video signal processed here is amplified to a prescribed level by an amplifier 109, and after being processed by an LCD (liquid crystal display) display circuit 110. , LCD111 constituting electronic viewfinder
To display the captured image.

On the other hand, the video signal amplified by the amplifier 107 is sent to the aperture control circuit 112 and the AF (autofocus) evaluation value processing circuit 115. In the aperture control circuit 112, the IG driver 11 operates according to the video signal input level.
3, the IG meter 114 is driven to control the diaphragm 103 to adjust the light amount.

In the AF evaluation value processing circuit 115, only the high frequency component of the video signal in the distance measuring frame is extracted and processed according to the gate signal from the distance measuring frame generating circuit 117.
Reference numeral 116 denotes an AF microcomputer, which controls the drive of the lens and the ranging frame control for changing the ranging area according to the AF evaluation signal strength. In addition, the AF microcomputer 116
Communicates with a system control microcomputer (hereinafter referred to as “syscon”) 122, and the syscon 122 is an A / D.
The zoom switch 123 read by conversion or the like (a unitized zoom switch outputs a voltage proportional to the rotation angle of the operating member. Variable speed zooming is performed according to this output voltage. Information), and zooming operation information such as a zooming direction and a focal length during zooming controlled by the AF microcomputer 116 are exchanged with each other.

Reference numerals 118 and 120 denote drivers 119 and 12 for outputting drive energy to a lens drive motor in accordance with drive instructions for the variable magnification lens 102 and the focus lens 105 output from the AF microcomputer 116, respectively.
Reference numeral 1 denotes a variable power lens 102 and a focus lens 1, respectively.
This is a motor for driving 05.

Assuming that the lens driving motors 119 and 121 are stepping motors, a method of driving the motors will be described below.

The AF microcomputer 116 determines the driving speeds of the variable power lens motor 119 and the focus lens motor 121 by the program processing, and the stepping motors 11 are driven.
The variable magnification lens motor 1 is used as the rotation speed signal of 9,121.
19 driver 118, focus lens motor 1
21 to the driver 120 for driving. In addition, the motor 119,
The drive / stop command of 121 and the rotation direction command of each motor are sent to the drivers 118 and 120. The drive / stop signal and the rotation direction signal are used for the variable power lens motor 119.
With respect to, mainly, according to the state of the zoom switch 123, with respect to the focus lens motor 121, according to a drive command determined by processing in the microcomputer 116 during AF and zoom. The drivers 118 and 120 set the phases of the four motor excitation phases to forward rotation and reverse rotation according to the rotation direction signal, and apply the four motor excitation phases according to the received rotation speed signal. Voltage (or current)
Output by changing the
The output to the motors 119 and 121 is turned on / off according to the drive / stop command while controlling the rotation direction and the rotation speed of the motors 9 and 121.

FIG. 2 is a diagram for explaining the operation of this embodiment. 2A shows the relationship between the output voltage of the zoom switch 123 and the zoom speed in the tele direction, and FIG. 2B shows the relationship between the output voltage of the zoom switch 123 and the zoom speed in the wide direction. Shows. The relationship between the voltage and the variable speed is changed non-linearly (for example, like a logarithmic curve) as shown in FIG. 2, and is gradually changed from low speed to medium speed, and is set to be changed at once from medium speed to high speed. . It should be noted that "variable speed" refers to the moving speed of the variable power lens, and does not directly refer to the changing speed of the focal length.

As a result, a subtle change can be made at a low speed, and a change from a low speed to a high speed can be felt smoothly.

(Embodiment 2) When a variable power operation is performed, a slight change at a low speed is possible, and in order to smooth the change from a low speed to a high speed, the relationship between the voltage and the variable speed is made non-linear. Those were described in Example 1.

In the case of the inner focus lens, when the object distance is changed at each focal length, the position of the focus lens for focusing on the image pickup surface is continuously plotted, as shown in FIG. Become. During zooming, if the locus shown in FIG. 3 is selected according to the subject distance and the focus lens 105 is moved along the locus, zooming without blurring is possible. However, as shown in FIG. 3, the inclination of the locus is large in the vicinity of the telephoto, and when the zooming operation is performed at high speed, the focus lens 105 also has to operate at high speed, and the maximum speed of the focus lens motor 121 is high. May exceed. In that case, the zoom speed near the telephoto end must be reduced.

Further, since the change in image magnification due to the zooming operation is large in the vicinity of the telephoto, if the zoom is performed at the same speed from the wide angle to the telephoto, there is a feeling that the zoom speed becomes abruptly increased in the vicinity of the telephoto. Therefore, in order to perform a smooth zooming operation, it is preferable to reduce the speed in the vicinity of the telephoto.

From the above viewpoint, the second embodiment is an example in which the speed is reduced near the telephoto. FIG. 4 is a diagram showing the relationship between the voltage and the variable speed, which is a feature of this embodiment. FIG. 4A shows the relationship between the output voltage of the zoom switch and the zooming speed in the tele direction, Ia shows the characteristics when the focal length of the lens system is on the wide side, and IIa shows the focal length of the lens system. Shows the characteristics when is on the tele side. FIG. 4B shows the relationship between the output voltage of the zoom switch and the zooming speed in the wide direction, Ib shows the characteristics when the focal length of the lens system is on the wide side, and IIb shows the focal length of the lens system. Shows the characteristics when is on the tele side. in this way,
The characteristics are changed depending on whether the focal length of the lens system is on the wide side or the tele side, the relationship between the voltage and the variable speed is made non-linear, and the characteristics are changed on the wide side and the tele side.
On the tele side, it is set to reduce the maximum speed. Although FIG. 4 shows an example in which two characteristics are set on the wide side and the tele side, a smoother zooming operation can be realized by setting a plurality of characteristics in accordance with the focal lengths.

(Embodiment 3) In Embodiment 1, an example using an inner focus type zoom lens is shown. In this embodiment, however, as shown in FIG. 5, a zoom lens having a focus lens at the front is used. Is. Even in the case of a so-called front lens, which has a focus lens in the front and a variable power lens and an aperture behind it in this way, there is a change in the zoom ratio due to zooming near the telephoto end. Since it is large, a smoother zooming operation can be realized by setting a plurality of non-linear characteristics as shown in FIG.

(Modification) In each of the above embodiments, the variable speed is instructed by the voltage, but the present invention is not limited to this, and it may be carried out by an appropriate electric variable, for example, an electric current. it can.

In each of the embodiments, the voltage value indicates the magnification changing direction and the magnification changing speed, but the present invention is not limited to this, and the voltage polarity changes the magnification changing direction and the voltage value changes the magnification. It can be implemented in a speed-indicating manner.

In each of the embodiments, the zoom switch of the camera body is used to instruct the zooming operation. However, the present invention is not limited to this, and the zooming operation can be instructed by a remote controller or the like. .

Although each embodiment is an example of a video camera, the present invention is not limited to this, and can be similarly implemented in a camera using film.

In each embodiment, the non-linear characteristic is set by software, but the present invention is not limited to this, and the non-linear characteristic is given by using a variable resistor whose output changes non-linearly in the operating member. It can be carried out.

[0031]

As described above, according to the present invention,
It is possible to provide a camera that can easily perform delicate zooming and can smoothly zoom. Specifically, according to the inventions of claims 1 to 3, by setting the relationship between the value of the electrical variable and the variable speed to a non-linear (for example, logarithmic curve) characteristic, a delicate variable operation can be easily performed. You can According to the third aspect of the present invention, a smoother zooming operation can be realized by setting a plurality of nonlinear characteristics according to the focal length of the lens system. According to the fourth aspect of the present invention, the variable speed is set to have a non-linear characteristic with respect to the movement of the operating member, so that a delicate variable operation can be easily performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is a diagram showing a relationship between a focal length and a focus lens position.

FIG. 4 is an operation explanatory diagram of the second embodiment.

FIG. 5 is a diagram showing a configuration of a lens system in Example 3.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 102 variable magnification lens 116 AF microcomputer 122 system controller 123 zoom switch

Claims (4)

[Claims] 1. A lens system having a variable power lens,
A camera comprising: an instructing means for instructing a zooming speed according to a value of an electric variable; and a driving means for driving the zooming lens in which the relationship between the value of the electrical variable and the zooming speed is a nonlinear characteristic. . 2. The camera according to claim 1, wherein the non-linear characteristic is a logarithmic curve characteristic. 3. The camera according to claim 1, wherein the non-linear characteristic is a plurality of characteristics set with respect to a focal length of the lens system. 4. A zooming method for a lens system, wherein the relationship between the movement of an operating member for instructing the zooming speed of the lens system and the zooming speed has a non-linear characteristic.