Camera Body Autofocus Without Lens Communication
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Solution Overview
Problem
In lens interchangeable digital cameras, the camera body struggles with accurate autofocus when it cannot communicate with the attached lens barrel, leading to poor focus adjustment accuracy and operability issues, especially when dealing with high-definition 4K images and shallow depth of field.
Innovation Solution
The camera body includes a controller and image sensor driver that detect optical feature changes and move the image sensor to a reference position within its movable range, allowing for automatic focus adjustment based on manual operations performed at the lens barrel side, even when communication with the lens barrel is not possible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the camera body cannot communicate with the attached lens barrel, then the autofocus accuracy deteriorates, but the device complexity is reduced
Solution Approach 1:
The patent introduces an intermediary mechanism where the camera body detects optical feature amounts (such as contrast) from images captured by the image sensor and uses this information to control the lens driving part. This intermediary approach allows the camera body to perform autofocus control without direct communication with the lens barrel, resolving the contradiction by maintaining autofocus accuracy through an alternative control path that doesn't rely on lens-barrel communication.
Solution Approach 2:
The patent implements a feedback mechanism where the camera body continuously detects optical feature amounts from captured images and adjusts the lens position based on the detected focus evaluation values. This closed-loop feedback system enables the camera body to achieve accurate autofocus control independently, without requiring communication with the lens barrel, thus resolving the technical contradiction.
2Ease of operation
If manual operations are performed at the lens barrel for focus adjustment, then the ease of operation is improved, but the device complexity increases due to communication requirements
Solution Approach 1:
The patent uses the camera body's image sensor and controller as an intermediary to detect the optical effects of manual lens operations and translate them into automated focus control. This allows users to perform simple manual operations at the lens barrel while the camera body handles the complex communication and control processing, improving ease of operation without actually increasing overall system complexity.
Data Source
AI summary
A camera body according to the present disclosure is a camera body to which a lens barrel including an optical system is detachable and reattachable, the optical system being configured to include a plurality of lenses. The camera body includes: a controller which controls the camera body; an image sensor which obtains an optical image formed by the optical system; and an image sensor driver which drives the image sensor in an optical axis direction of the optical system. The controller detects optical feature amounts of a plurality of frames in a state where the image sensor is at an identical position in the optical axis direction, detects a frame in which a change amount of an optical feature amount calculated from a plurality of the detected optical feature amounts has exceeded a predetermined threshold, and drives the image sensor driver to move the image sensor from the identical position to a reference position provided in a movable range when there is a plurality of the frames in which the change amount has exceeded the predetermined threshold.