Lens Control Apparatus for Variable Shortest Distance
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Solution Overview
Problem
Existing lens control systems for cameras with zoom mechanisms fail to maintain favorable operability and natural focusing when the shortest photographing distance changes with focal length, leading to inadequate resolution and balance in distance scale indications, resulting in unnatural user experience.
Innovation Solution
A lens control apparatus and method that includes a focusing lens, a rotatable ring member, and a controller, which stores and selects relationships between the ring's rotation angle and photographing distance, adjusting the focusing lens position to maintain consistent operability across varying focal lengths by altering the slope of the focus position relationship with respect to the distance ring's rotation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single relationship between ring rotation angle and photographing distance is used, then the device complexity is reduced, but the measurement precision of photographing distance deteriorates when shortest photographing distance changes
Solution Approach 1:
The patent applies dynamics by making the relationship between ring rotation angle and photographing distance changeable based on operating conditions. Specifically, the control unit switches between a first relationship (when shortest photographing distance is fixed) and a second relationship (when shortest photographing distance varies with focal length), allowing the system to adapt to different zoom states and maintain accurate distance indication without requiring a completely complex new system architecture.
Solution Approach 2:
The patent implements parameter changes by modifying the relationship parameters between ring rotation angle and photographing distance based on the zoom lens state. When the focal length changes and shortest photographing distance varies, the control unit changes the relationship parameter from the first type to the second type, thereby maintaining accurate distance scale indication across different photographing conditions without increasing overall device complexity.
2Adaptability or versatility
If the shortest photographing distance changes with focal length, then the adaptability of the photographing lens is improved, but the ease of operation deteriorates due to unnatural focusing behavior
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the relationship between ring rotation angle and photographing distance based on the current focal length and shortest photographing distance. When the shortest photographing distance changes with focal length, the control unit switches to the second relationship, which maintains consistent focusing behavior and natural operation feeling for the user, thereby preserving ease of operation while adapting to different photographing conditions.
Solution Approach 2:
The patent implements feedback by having the control unit continuously monitor the focal length and shortest photographing distance, then automatically selecting the appropriate relationship (first or second) based on the current state. This feedback mechanism ensures that the distance scale indication and focusing behavior remain natural and consistent from the user's perspective, even as the adaptability to different focal lengths is improved.
3Ease of manufacture
If a linear relationship between ring rotation angle and photographing distance is used, then the ease of manufacture is improved, but the measurement precision of distance scale indication deteriorates
Solution Approach 1:
The patent applies dynamics by making the relationship between ring rotation angle and photographing distance adaptive rather than fixed. Instead of using a single static linear relationship, the system dynamically selects between the first relationship (optimized for fixed shortest distance) and the second relationship (optimized for variable shortest distance), thereby maintaining high measurement precision across different conditions without complicating the manufacturing process.
Solution Approach 2:
The patent implements parameter changes by switching between different relationship parameters based on the zoom lens state. When the shortest photographing distance changes with focal length, the control unit changes from the first relationship parameter set to the second relationship parameter set, which provides better distance scale resolution and measurement precision while maintaining ease of manufacture through the use of predefined relationship models.
Data Source
AI summary
A lens control apparatus having a focusing lens capable of moving in an optical axis direction provided within a lens barrel including a photographing lens, comprising; a ring rotatably disposed to the lens barrel; a memory storing a first relationship between a rotation angle of the ring and a value relating to a photographing distance corresponding to a first photographing distance area and a second relationship between a rotation angle of the ring and a value relating to a photographing distance corresponding to a second photographing distance area on a shorter distance side than the first photographing distance area; and a controller controlling a position in an optical axis direction of the focusing lens by selecting the first relationship or the second relationship in accordance with a rotation angle of the ring and calculating a value relating to a photographing distance in accordance with a rotation angle of the ring.