Aperture Control Resolution Switching for Camera Exposure Accuracy
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Solution Overview
Problem
Existing optical apparatuses with electronic ring type aperture rings face accuracy issues in still image capturing due to fine detecting resolution of the rotation position, leading to errors in aperture value control, which affects the desired luminance of still images.
Innovation Solution
An optical apparatus with a processor that generates a target aperture value using both a first and a second resolution, allowing for accurate control of the aperture unit based on user input from an operation member, incorporating correction values to address assembly and part accuracy errors, and adjusting the rounding resolution for optimal aperture control in both still and moving image capturing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the detecting resolution of the rotation position of the aperture ring is increased to achieve smooth aperture value changes during moving image capturing, then the response of the aperture value control becomes smooth, but the aperture value accuracy is lowered particularly in still image capturing
Solution Approach 1:
The patent applies dynamics by switching between two different processing modes (first processing for still images, second processing for moving images) based on the capturing mode. The system dynamically adjusts how the target aperture value is generated from the specified aperture value, using coarse rounding for still images to ensure accuracy and fine rounding for moving images to ensure smooth transitions.
Solution Approach 2:
The patent changes the parameter of rounding resolution based on the capturing mode. For still image capturing, it uses first processing with lower resolution rounding to maintain aperture accuracy. For moving image capturing, it uses second processing with higher resolution rounding to achieve smooth aperture transitions. This parameter change resolves the contradiction between accuracy and smoothness.
2Ease of operation
If the driving resolution of the electromagnetic aperture stop is increased to achieve fine aperture value control, then the response becomes smooth during moving image capturing, but assembly errors and part accuracy errors cause residual errors in aperture value
Solution Approach 1:
The patent incorporates feedback by detecting the actual rotation position of the aperture ring and using this information to generate the target aperture value. The system monitors the operation member's position and adjusts the aperture stop accordingly, ensuring that the actual aperture value matches the intended value despite assembly errors or manufacturing tolerances.
Solution Approach 2:
The patent performs preliminary action by pre-calculating the target aperture value based on the detected rotation position before actuating the aperture stop. This allows the system to compensate for potential errors in advance, ensuring accurate aperture positioning by accounting for assembly and manufacturing variations before the actual aperture adjustment occurs.
Data Source
AI summary
An optical apparatus includes an aperture unit having a variable aperture value, an operation member operable by a user and configured to set the aperture value, and a processor configured to output a specified aperture value according to an operation of the operation member, generate a target aperture value from the specified aperture value, and control driving of the aperture unit based on the target aperture value. The processor performs one of first processing for generating the target aperture value with a first resolution from the specified aperture value, and second processing for generating the target aperture value with a second resolution, which is finer than the first resolution, from the specified aperture value.