JPH0476524A - Focusing device - Google Patents

Abstract

PURPOSE:To allow a photographer to perform optimum automatic focusing operation matching the purpose of use by optionally selecting response characteristics in the automatic focusing operation. CONSTITUTION:The operator inputs data values corresponding to a desired automatic focusing driving speed, the reaction time up to the start of the focusing operation to an A/D converter 2 through a variable resistor 1. The data are inputted to a microcomputer 3. Then when the automatic adjusting operation is performed and a motor driver 4 is driven according to a specified response characteristic to perform the focusing operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a focus adjustment device, and more particularly, to a focus adjustment device in which response characteristics during automatic focus adjustment operation can be selected.

[Prior Art] In recent years, many proposals have already been made regarding automatic focus adjustment devices for cameras, etc., and there have also been proposals regarding methods for varying the focusing drive speed, which is the response characteristic during focusing operations in the adjustment device. Several things have also been proposed. For example, the automatic focus adjustment type cine camera disclosed in Japanese Patent Application Laid-Open No. 54-86325 is equipped with an automatic focus adjustment mechanism, and the operating speed of the automatic focus adjustment mechanism is made slower during shooting than before the start of shooting. The apparatus is equipped with a control means, and during photographing, the operating speed of the automatic focus adjustment mechanism in response to changes in the distance of the object to be measured is made slower than before the cine camera starts driving. This operation is designed to eliminate unnatural movement of the focus position on the photographic screen, and accompanying changes in the angle of view and magnification.

Further, the automatic focusing device for a zoom lens disclosed in Japanese Patent Application Laid-Open No. 56-162728 provides focal length information linked to zooming operations in a zoom lens system in which the focusing adjustment distance of the focusing lens group changes depending on the focal length. The apparatus includes a detection means, and the driving speed of the focusing lens group is changed according to the focal length based on the output signal of the detection means. Furthermore, JP-A-59-20
The focusing device disclosed in Publication No. 0205 electrically connects an AF detection device that automatically detects the focus state of a subject and a manual operation device that can be operated from outside the device to an electric motor that selectively drives a focus lens for focusing. In the focusing device, an output signal of the manual operating means attached between the manual operating means and the electric motor is taken in, and the focusing drive speed of the electric motor is set in advance to a manual speed that is easy to manually operate. It is automatically controlled.

[Problems to be Solved by the Invention] However, in each of the above-mentioned focus adjustment devices, the driving speed, which is one of the focusing response characteristics during automatic focusing operation, cannot be set to an arbitrary value. It was something. Therefore, if you try to photograph a fast-moving subject such as a moving car or a person using a focus adjustment device with a preset eye movement focusing drive speed, the focus adjustment will be difficult if you do not increase the autofocus drive speed. There was a possibility that the device would not be able to track the subject and become unable to focus.

Furthermore, in each of the above-mentioned focus adjustment devices, the reaction time until the start of the focusing operation, which is one of the focusing response characteristics, cannot be set to an arbitrary value in any case; If you try to photograph a fast-moving subject such as a car or a person, the start of focusing will be delayed, making it impossible to photograph. Furthermore, if the reaction time until the start of the focusing operation is too short, for example, when trying to focus on a specific main subject in a crowd, there may be an object that crosses the focus adjustment device side of the main subject. There was a problem where autofocus started immediately on the main subject, causing the main subject to become blurry.

Note that the focusing drive speed during the automatic focusing operation above refers to the operating speed during the focusing operation, and the reaction time until the start of the focusing operation refers to the time required for the focused subject to move again after the end of the focusing operation. or the time from the time when a new subject is tried to be focused until the focus adjustment device starts automatic focusing operation again.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to enable the above-mentioned response characteristics during automatic focusing operation to be selected as desired by the operator, thereby achieving more appropriate focusing operation for any subject. It is an object of the present invention to provide a focus adjustment device that can perform automatic focusing operations that are optimal for each purpose of use by each photographer.

[Means and effects for solving the problem] The focus adjustment device of the present invention responds with predetermined response characteristics to information representing the object distance or the sharpness of the image related to the object, and automatically performs the focus adjustment operation. A focus adjustment device configured as follows, characterized in that the response characteristics during automatic focus adjustment operation can be selected at the operator's discretion,
Set the above response characteristics according to the subject or purpose, etc.
This enables appropriate focusing.

[Example of implementation] The present invention will be described below based on illustrated embodiments.

FIG. 1 is a block configuration diagram of a focus adjustment device showing a first embodiment of the present invention. This device responds with predetermined response characteristics to information representing the object distance or the sharpness of an image related to the object, and automatically The focus adjustment operation is performed in the following manner. This device includes a variable m resistance i1, an A/D converter 2, a microcomputer 3, a motor driver 4, a motor 5,
It is composed of a focusing lens 6. The microcomputer 3 is responsible for all controls of this device. The variable resistor 1 is a variable resistor that is manually set, and data specifying the focusing drive speed, that is, the drive speed of the motor driver 4, indicating the response characteristics during automatic focusing operation, or The A/D converter 2 sends data specifying the reaction time until the start of the focusing operation, that is, the response delay time or time constant, etc., which is the time from when the focusing operation instruction is output until the motor driver 4 starts driving. This is what you input. Above A/D
Converter 2 converts the output data of variable resistor 1 into A/
The data is converted into D and input to the microcomputer 3. The motor driver 4 drives a focusing drive motor based on instructions from the microcomputer 3.

Further, the motor 5 drives the focusing lens 6 to the in-focus position.

The operation of the focus adjustment device of this embodiment configured as described above is as follows: First, the operator inputs a data value corresponding to the desired automatic focus drive speed or reaction time until the start of the focus operation to the variable resistor 1. The signal is input to the A/D converter 2 via the . The data is taken into the microcomputer 3. Note that it is necessary to always identify whether the data imported here is the driving speed or the reaction time.

Then, when performing a focus adjustment operation, the heptad driver 4 is driven according to the designated response characteristic, and focusing is performed. Therefore, according to this embodiment, the operator can specify the focusing speed or the focusing operation start reaction time depending on the type of subject or the purpose of use, thereby making it possible to perform optimal focus adjustment.

Note that the variable resistor 1 functions to convert manual mechanical operations into electrical signals, and can be replaced with any input means having a similar function. If a device that directly converts the signal into a digital signal using a digital switch, decoder, etc. is used, the signal can be input directly to the microcomputer 3 without using the A/D converter 2.

In addition, the above response characteristics may be based only on the response speed or time delay of the focusing operation, or may also be calculated using a ROM table or an analog function generator built into the microcomputer 3 to calculate the distance.

It is also possible to make the focusing device function more precisely by specifying the output ratio of input information such as sharpness to adjustment output. Of course, the data on the autofocus drive speed and/or the reaction time until the start of drive described above are stored in advance in the ROM built into the microcomputer 3, without inputting them from the variable resistor 1, and the values can be stored in advance in the ROM built into the microcomputer 3. It is also possible to read out and perform focusing.

The functionality can be further improved by switching which designation method to select depending on the purpose of use.

Next, a focus adjustment device showing a second embodiment of the present invention will be explained with reference to the block diagram of FIG. In this embodiment, the automatic focusing drive speed and the reaction time until the start of the focusing operation, which are the response characteristics during the automatic focusing operation, are set and input using independent variable resistors 7 and 8, respectively. The focus adjustment device of this embodiment includes variable resistors 7 and 8, an analog switch 9, an A/D converter 10, a microcomputer 11, a motor driver 12, a motor 3, and a focusing lens 14.

When the operator specifies the response characteristics described above, the analog switch 9 switches the connection between the variable resistors 7 and 8 via the microcomputer 11.

It is assumed that the variable resistor 7 inputs data specifying the automatic focusing drive speed among the response characteristics, and the variable resistor 8 inputs data specifying the above-mentioned reaction time. Then, any of the above data is digitally converted by the A/D converter 10 and taken into the microcomputer 11. Subsequently, based on the selected data, a focusing operation of the focusing lens 14 that drives the motor 13 via the motor driver 12 is performed.

Next, the process of setting the response time in the automatic focus adjustment operation in this embodiment will be explained with reference to the flowchart of FIG.

First, in step 5101, the switching flag F is reset to O. Next, the flag F is checked (step 5102), and if F is 0, the process proceeds to step 8103, and if F is 1, the process proceeds to step 5106. Note that at the beginning of the processing operation, the flag F is reset to 0, so the process proceeds to step 8103. In step S103, the analog switch 9 is switched to the connection side of the variable resistor 7. Then, the data of the automatic focusing drive speed specified by the variable resistor 7 is transferred to the A/D converter 10.
via the microcomputer 11, and the drive speed setting described above is performed (step S104). Next, flag F is set to 1 (step 5105),
Return to step 5 IC12 again. In this case, since flag F is 1, the process advances to step 5106.

In step 5106, the analog switch 9 is switched to the connection side of the variable resistor 8. And variable resistor 8
The data on the reaction time until the start of the focusing operation specified in is taken into the microcomputer 11 via the A/D converter 10, and the reaction time is set (step 5107).

Next, step 5108 resets the flag F to 0.
Then, the process returns to step 5102, and the setting operation is repeated.

As described above, according to this embodiment, the settings for the focus drive speed and focus start reaction time can be input using independent variable resistors, so these settings can be made more reliably. Become.

In this embodiment, as in the case of the first embodiment, the variable resistors 7 and 8 can be replaced with any means having an equivalent input function. For example, by using digital switches, decoders, etc., direct digital If a converter that can be converted into a signal is used, the A/D converter 10 can be omitted and its output end can be directly connected to the microcomputer 11.

Further, data on the focusing drive speed and focusing start reaction time are stored in advance in a ROM built into the microcomputer 11, and input via the variable resistors 7 and 8, or directly from the ROM. Alternatively, it is possible to switch depending on the purpose of use.

Furthermore, the focus adjustment device of the present invention is applied to a camera having a still/movie mode switching function, and the automatic focusing drive speed and reaction time until the start of the focusing operation can be changed in accordance with the mode switching or mode state. If it is possible to automatically set this, it is possible to provide a camera with higher focusing performance.

[Effects of the Invention] As described above, the focus adjustment device of the present invention allows the operator to arbitrarily select the response characteristics of the automatic focus adjustment operation. Even for fast-moving subjects such as people, the operator can, for example, set the focus drive speed and match the followability to the subject. In addition, in shooting situations where non-main subjects that are not the intended main subject frequently cross in front of the focus adjustment device, the operator may, for example, set a longer reaction time before starting the focusing operation. , it becomes possible to keep focusing only on the main subject without focusing on non-main subjects. In this way, even under various subject conditions, the operator can select and specify various response characteristics according to the subject, thereby achieving remarkable effects such as allowing the optimal focusing operation to be executed. It is possible to provide a focusing device having the following.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a focus adjustment device showing a first embodiment of the present invention. FIG. 2 is a block configuration diagram of a focus adjustment device showing a second embodiment of the invention. FIG. 3 is a flowchart of focusing operation response characteristic setting processing in the focus adjustment device of FIG. 2; 1.7.8...Variable resistor (response characteristic setting means during focusing operation)

Claims (1)

[Claims] (1) A focus adjustment device configured to respond to information representing the object distance or the sharpness of an image of the object with a predetermined response characteristic and automatically perform a focus adjustment operation, which is an automatic focus adjustment device. A focusing device characterized in that the response characteristics during operation can be selected at the operator's discretion.