Interchangeable Lens Autofocus Control for Moving Image Stability
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Solution Overview
Problem
Conventional camera systems with interchangeable lenses face challenges in performing suitable autofocus control during moving image recording, especially when the zoom lens is in a wide-angle position, leading to fluctuations in field angle and unsightly images due to wobbling control.
Innovation Solution
An interchangeable lens system that stores link information correlating the position of the zoom lens with magnification variations, allowing the camera body to generate and transmit control signals to the focus driver for precise autofocus control, adjusting the wobbling amplitude based on the zoom lens's position to maintain image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wobbling control is performed for autofocus during moving image recording, then focus regulation is achieved, but field angle fluctuates and images become unstable especially at wide-angle positions
Solution Approach 1:
The patent applies dynamics by making the wobbling control parameters adjustable based on zoom lens position. The control system dynamically changes the wobbling amplitude and frequency according to the current zoom state, allowing optimal autofocus performance at each zoom position while minimizing field angle fluctuations. This is achieved through the control unit receiving zoom position information and adjusting wobbling parameters accordingly.
Solution Approach 2:
The patent changes control parameters (wobbling amplitude, frequency, or duration) based on the zoom lens position. When the zoom lens is at wide-angle positions, the system reduces wobbling amplitude or frequency to minimize field angle fluctuations. At telephoto positions, normal or different wobbling parameters are used. This parameter adaptation resolves the contradiction between achieving focus regulation and maintaining field angle stability.
2Adaptability or versatility
If conventional autofocus control is used during moving image recording, then focus adjustment is possible, but automatic focus regulation cannot suitably perform for every state of the zoom lens
Solution Approach 1:
The patent makes the autofocus control system dynamic by continuously monitoring zoom lens position and adjusting wobbling control parameters in real-time. The control unit receives information about the current zoom state and adapts the autofocus algorithm accordingly, ensuring reliable focus regulation across all zoom positions from wide-angle to telephoto.
Solution Approach 2:
The patent implements feedback by having the control unit receive zoom position information from the lens unit and use this information to adjust wobbling control parameters. This closed-loop approach ensures that the autofocus system adapts to changing optical conditions at different zoom positions, improving both adaptability and reliability of focus control.
Data Source
AI summary
An interchangeable lens has a zoom lens, a zoom driver operable to drive the zoom lens along an optical axis, a focus lens, a focus driver operable to drive the focus lens along the optical axis, and a storage unit operable to store link information which links position information indicating a position of the zoom lens on the optical axis with information about a variation in magnification caused by the focus lens advancing and retreating on the optical axis with the zoom lens located at the position indicated by the position information.