US 4,733,262 AGranted

Camera system capable of automatic focus control

AssigneeMinolta Camera Kabushiki Kaisha

InventorsNobuyuki Taniguchi, Norio Ishikawa, Yasuaki Akada, Takeshi Egawa, Kunio Kawamura

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Abstract

A camera system with an auto-focusing system includes a camera body and an interchangeable zoom lens. The interchangeable objective lens stores various data to be sent to the camera body for improving automatic focus adjustment, such as an information necessary to convert the detected defocus information into a movement of the driving power source to carry out the automatic focus adjustment. The driving power source in the camera body is controlled in response to the data from the interchangeable objective lens and the detected focus information, the driving power being transmitted to the interchangeable objective lens. The camera body is further capable of inhibiting the focus adjustment or focus indication in response to a data from the interchangeable objective lens under an unfavorable condition.

Claims11

Dependent claims

In a camera system capable of automatic focus control in response to focus detection by means of receiving light from an object through an optical system, an improvement comprising:

means for receiving light through the optical system to produce electric signals;
means for processing the electric signals to generate defocusing information indicative of the degree of defocusing and defocusing direction relative to a predetermined plane;
means for generating a driving power and for driving said optical system for automatic focus control;
means for controlling the generating means in response to the processing means;
means for causing the receiving means and the processing means to periodically repeat the production of the electric signals and the generation of the defocusing information during the generation of the driving power to keep the controlling means informed of the most recent defocusing information in the course of generation of the driving power;
means for detecting when the optical system is in a near-focus zone and for reducing the amount of said driving power in response to said detection including first means responsive to the processing means for reporting an in-focus condition during the generation of the driving power, and second means response to the processing means for reporting an in-focus condition with the generation of the driving power completely stopped;
and
means for stopping the generation of the driving power in response to the second reporting means to fix the focus adjustment for picture taking when the in-focus condition is reported.

5 more elements

In a camera system having a predetermined focal plane and capable of automatic focus control in response to focus detection by means of receiving light from an object through an objective lens system, an improvement comprising:

means for receiving light through the objective lens system representative of an image of the object and producing electric signals representative of that image;
means for processing the electric signals to generate defocusing information indicative of the degree of defocusing of the image relative to the predetermined plane;
means for moving the objective lens system to adjust the focus of the image;
means for controlling the moving means;
means for keeping the controlling means informed of the most recent defocusing information in the course of moving the lens system;
means for detecting a condition for stopping the movement of the objective lens system, and
means for confirming the establishment of the condition in response to the processing means with the objective lens system completely stopped to determine the necessity of further moving the lens system in case the condition is not finally established, wherein the detecting means includes first means responsive to the processing means for reporting an in-focus condition during movement of the lens system, and the confirming means includes second means responsive to the processing means for reporting an in-focus condition with the lens system completely stopped, and means for movement of the lens system in response to the second reporting means to fix the focus adjustment for picture taking when the in-focus condition is reported.

4 more elements

Dependencies are inferred from the claim text.