Automatic focusing device and automatic exposure control device

• US 4,728,980 A
• Filed: 08/04/1986
• Issued: 03/01/1988
• Est. Priority Date: 08/05/1985
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Ando, Makoto, Taniguchi, Nobuyuki, Nakamura, Akiyoshi, Ogino, Shuji
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US06/893,363
• Time in Patent Office: 575 Days
• Field of Search: 354/400, 354/195.1, 354/195.12, 354/286, 354/402
• US Class Current: 396/71
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: G03B 7/095 for control of aperture

Abstract

An automatic focusing device which comprises a defocus amount detecting unit for detecting a defocus amount attributable to a first optical system of an interchangeable lens assembly and a second optical system of an AF convertor, a converting circuit for converting the defocus amount into a data corresponding to a focusing amount of the second optical system which varies in non-linear relationship to the defocus amount, and an optical drive unit for moving the second optical system on the basis of a data representative of the focusing amount supplied from the converting circuit.

Claims

1. An automatic focusing device which comprises:

a defocus amount detecting means for detecting a defocus amount attributable to a first optical system of an interchangeable lens assembly and a second optical system of an AF convertor;

a position data outputting means for outputting position data representative of the position of the second optical system;

a converting means for converting said defocus amount, taken into consideration with the position data, into data corresponding to a focusing amount of the second optical system which varies in non-linear relationship to said defocus amount; and

an optical drive means for moving the second optical system on the basis of the data representative of the focusing amount supplied from the converting means.

2. An automatic focusing device which comprises:

a focusing amount calculating means for calculating a focusing amount of a second optical system of an AF convertor, which amount is necessary to bring an image of a target object, passing through both of a first optical system of an interchangeable lens assembly and the second optical system of the AF convertor, into an in-focus condition;

a current position data outputting means for outputting a data representative of the current position of the second optical system;

a limit position data outputting means for outputting a first limit position data representative of the limit position for the extension of the second optical system and also a second limit position data representative of the limit position for the retraction of the second optical system;

a focus control determining means for determining, on the basis of the combination of the focusing amount supplied from the calculating means, the data representative of the current position and the data representative of the first or second limit position, whether or not the target object can be controlled into the in-focus condition if said second optical system is moved a distance corresponding to the focusing amount; and

a first means for displaying the direction in which the first optical system of the interchangeable lens assembly is to be moved for bringing the target object, which is in a defocused condition, into the in-focus condition, in the event that said determining means makes a negative decision.

3. The device as claimed in claim 2, further comprising a second means for driving the second optical means to one of the first and second limit positions in a direction in which the in-focus condition lies, in the event that said determining means makes the negative decision.

4. An automatic exposure control device which comprises:

a full aperture metering means;

an actual aperture metering means;

a mounted optical system detecting means for detecting a first condition in which a first photo-taking optical system adaptable to said full aperture metering means is mounted, a second condition in which a second photo-taking optical system inadaptable to said full aperture metering means is mounted, and a third condition in which none of the first and second photo-taking optical systems is mounted;

an automatic focus adjusting means capable of adjusting the focus of the first photo-taking optical system and the focus of the second photo-taking optical system; and

a control means for enabling both of said automatic focus adjusting means and said full aperture metering means upon the detection of the first condition by said mounted optical system detecting means, for enabling both of said automatic focus adjusting means and said actual aperture metering means upon the detection of the second condition by said mounted optical system detecting means, and for disabling said automatic focus adjusting means and enabling said actual aperture metering means upon the detection of the third condition by said mounted optical system detecting means.