Focus Lens Control for Manual Focus Precision

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Solution Overview

Problem

Existing digital camera focus adjustment systems make manual focus operations cumbersome, as the sensitivity of focus lens movement is not optimally adjusted based on the focus degree and operation speed, leading to difficulties in precise focus adjustment.

Innovation Solution

A focus adjustment apparatus and method that adjusts the movement amount of the focus lens per unit of operation amount based on the focus degree and operation speed, with higher sensitivity when the focus degree is high and lower sensitivity when close to focus, and automatically adjusts the focus threshold and operation sensitivity to facilitate easier manual focusing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the focus lens movement sensitivity is increased to improve focus adjustment speed, then the focus adjustment speed is improved, but the focus precision deteriorates when near focus

Engineering Contradiction:

Improvefocus adjustment speedVSAvoidfocus precision

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the focus lens movement amount variable based on the current focus state. The driving unit dynamically adjusts the movement amount according to the focus degree, transitioning from larger movements when out of focus to smaller movements when near focus, thereby resolving the contradiction between speed and precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of focus lens movement amount based on the focus degree. By adjusting this parameter dynamically - using larger movement amounts when the focus degree is low and smaller movement amounts when the focus degree is high - the system achieves both fast adjustment speed and high precision focus.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the focus lens movement amount is reduced when near focus to improve precision, then the focus precision is improved, but the focus adjustment speed deteriorates

Engineering Contradiction:

Improvefocus precisionVSAvoidfocus adjustment speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The system dynamically adjusts the focus lens movement amount based on real-time focus degree feedback. When the focus degree is high (near focus), the movement amount is reduced for precision; when the focus degree is low (far from focus), the movement amount is increased for speed. This dynamic adaptation resolves the speed-precision tradeoff.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic measurement of focus degree and periodic adjustment of movement amount. The obtaining unit periodically obtains focus degree, and the driving unit periodically adjusts the movement amount accordingly, creating a cyclic control process that maintains both speed and precision throughout the focusing operation.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If a fixed focus threshold is used to control sensitivity switching, then the control logic is simplified, but the adaptability to different focusing scenarios deteriorates

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidadaptability to focusing scenarios

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the focus threshold parameter dynamically based on the direction of focus lens movement. When moving in the direction that increases focus degree, a higher threshold is used; when moving in the direction that reduces focus degree, a lower threshold is used. This parameter adaptation improves versatility while maintaining reasonable control logic.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The focus threshold is made dynamic rather than fixed. The determining unit sets different threshold values according to the movement direction of the focus lens, allowing the system to adapt to different focusing scenarios (focusing toward or away from the subject) and improving versatility without excessive complexity.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If the operation sensitivity is increased when focus degree is high to improve ease of operation, then the ease of operation is improved, but the risk of overshooting focus deteriorates

Engineering Contradiction:

Improveease of manual focus operationVSAvoidrisk of overshooting focus

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent changes the operation sensitivity parameter based on the focus degree and movement direction. By adjusting the sensitivity parameter dynamically, the system provides ease of operation when appropriate while preventing overshooting through reduced sensitivity near the focus point, thus resolving the contradiction between ease of operation and reliability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11237458B2Focus adjustment apparatus, image capturing apparatus, focus adjustment method, and storage medium

Publication Date: 2022.02.01 CANON KK

AI summary

There is provided a focus adjustment apparatus. A first obtainment unit obtains a focus degree in a predetermined region of a shooting range. A driving unit drives a focus lens in response to an operation unit being operated. A movement amount of the focus lens per unit of an operation amount of the operation unit during the driving is lower in a case where the focus degree is greater than a focus threshold than in a case where the focus degree is lower than the focus threshold. The focus threshold is higher in a case where the focus lens is moving in a direction that increases the focus degree than in a case where the focus lens is moving in a direction that reduces the focus degree.