Focus Lens Driver for Constant Manual Rotation
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Solution Overview
Problem
Existing image pickup apparatuses face difficulties in providing user-friendly manual focus adjustment, especially in macro photography, as the rotation amount required for focus adjustment increases significantly with shorter subject distances, leading to inconvenient and time-consuming operations.
Innovation Solution
The image pickup apparatus incorporates a focus lens driver that maintains a constant rotation amount for focus position adjustments regardless of subject distance, using a lens controller to calculate and control the focus movement based on the rotation of the manual focus ring, ensuring consistent operation across varying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the focus lens is moved according to the rotation amount of the manual focus ring without compensation, then the focus adjustment mechanism is simple, but the rotation amount required for focus adjustment increases significantly at short subject distances, making operation inconvenient
Solution Approach 1:
The patent applies dynamics by making the focus lens drive amount variable based on subject distance. The lens controller dynamically adjusts the drive amount according to the detected subject distance, ensuring that the focus lens moves an appropriate amount regardless of whether the subject is far or near. This resolves the contradiction by adapting the system behavior to different operating conditions, maintaining consistent manual focus adjustment characteristics across all subject distances.
Solution Approach 2:
The patent implements feedback by using the subject distance detection result to control the focus lens drive amount. The lens controller receives feedback about the subject distance and adjusts the focus lens positioning accordingly. This feedback mechanism ensures that the rotation amount at the manual focus ring remains constant across different subject distances, improving ease of operation and reducing adjustment time.
2Ease of operation
If the focus lens drive amount is increased to maintain constant rotation amount at the operating section, then manual focus adjustment becomes consistent across all distances, but the system complexity increases due to additional control calculations
Solution Approach 1:
The patent replaces a purely mechanical focus adjustment system with an electronically controlled system. Instead of using a mechanical linkage between the manual focus ring and focus lens, the system uses a lens controller with calculation units that electronically determine the focus lens drive amount based on subject distance. This substitution allows for more flexible and adaptive control while managing system complexity through software-based solutions.
Solution Approach 2:
The patent changes the parameter of focus lens drive amount based on subject distance. The lens controller adjusts this parameter dynamically, ensuring consistent manual focus adjustment characteristics. By varying the drive amount parameter according to detected subject distance, the system maintains operational consistency without requiring complex mechanical modifications.
Data Source
AI summary
The image pickup apparatus has a focus lens that adjusts focus on a subject, an operating section (an MF operation ring) that accepts user's operation, and a focus-lens driver that drives the focus lens in response to the user's operation. The focus-lens driver drives the focus lens so that a rotation amount at the operating section, which is required for moving a focus position by unit distance, is maintained at a constant level with no regard to a subject distance.