Focus Control Apparatus Using Lens-Specific Correction Data
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Solution Overview
Problem
Existing lens-interchangeable image capturing apparatuses face challenges in achieving accurate focus control due to aberrations and individual differences in interchangeable lenses, which are not effectively addressed by existing correction methods.
Innovation Solution
A focus control apparatus that includes a focus detector and a controller using correction values specific to each interchangeable lens, with a memory system to store and retrieve correction data for precise focus control, allowing for both fast and accurate focus adjustments based on the lens's unique characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction values are calculated for each interchangeable lens to account for individual differences, then in-focus accuracy is improved, but device complexity and processing time increase
Solution Approach 1:
The system performs preliminary calculation of correction values during lens manufacturing and stores them in the lens memory. This preliminary action eliminates the need for complex real-time calculations during focus operations, thereby improving in-focus accuracy while avoiding increased processing complexity during actual use.
Solution Approach 2:
The patent creates a copy of the correction value calculation data in the lens memory (separate from the master data). This copying approach allows the camera to use pre-calculated correction values without needing to recalculate them each time, reducing processing complexity while maintaining high in-focus accuracy through individualized correction for each lens.
2Measurement precision
If correction value calculation data is stored in each interchangeable lens, then individual lens differences are accounted for, but manufacturing complexity increases
Solution Approach 1:
The patent stores correction values (numerical parameters) rather than complex optical correction mechanisms. This parameter-based approach simplifies manufacturing by requiring only data storage capability in the lens memory, rather than complex physical adjustments or custom optical designs for each lens.
Solution Approach 2:
The patent replaces potential mechanical or optical correction systems with a digital data storage and processing system. By substituting physical correction mechanisms with stored correction value data, the manufacturing process becomes simpler while still achieving accurate focus detection that accounts for individual lens differences.
3Productivity
If pre-calculated correction values are used for lenses without individual data, then fast focus control is achieved, but accuracy may be compromised for lenses with significant individual differences
Solution Approach 1:
The system incorporates feedback through the focus detector that continuously monitors focus state. This feedback mechanism allows the camera to verify whether pre-calculated correction values are achieving adequate focus accuracy, and to make real-time adjustments if needed, thereby maintaining both fast focus control speed and high in-focus accuracy.
Solution Approach 2:
The patent implements a dynamic system where the camera can adaptively switch between using pre-calculated correction values (for speed) and calculating new correction values from individual lens data (for maximum accuracy). This dynamic approach allows the system to optimize the balance between focus control speed and in-focus accuracy based on the specific lens attached and shooting conditions.
Data Source
AI summary
The focus control apparatus performs focus control of the interchangeable lens by using information obtained through detection of a focus state of an interchangeable lens and a correction value corresponding to the interchangeable lens. The interchangeable lens is a first interchangeable lens holding unique correction value calculation data used to calculate the correction value, or a second interchangeable lens not holding the correction value calculation data. The focus control apparatus includes a first memory storing values for calculating the correction value corresponding to the second interchangeable lens. A controller calculates the correction value by using the correction value calculated based on the values read from the first memory when the second interchangeable lens is attached to the image capturing apparatus, and by using the correction value calculation data acquired from the first interchangeable lens when the first interchangeable lens is attached to the image capturing apparatus.