Live View Exposure Control for Consistent Brightness

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Solution Overview

Problem

Conventional image capturing apparatuses do not effectively control exposure conditions for live view images based on selected display modes, leading to inconsistent brightness during live view display, which can be unsuitable for user purposes.

Innovation Solution

An image capturing apparatus and control method that dynamically adjust exposure conditions by using a system controller to manage aperture and shutter settings based on selected live view display modes, employing exposure hold values to maintain optimal brightness levels for each mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If exposure conditions are controlled for live view display, then brightness consistency is improved, but device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvebrightness consistencyVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system controller performs multiple functions: it controls both the aperture mechanism and shutter mechanism, and manages both still image shooting and live view display operations. By making the controller universal, the patent avoids adding separate dedicated control units for each function, thus improving brightness consistency without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent dynamically adjusts exposure parameters (aperture value and shutter speed) based on the selected display mode. The controller changes these parameters in real-time to maintain appropriate brightness levels for different modes (EVF, through-display, etc.), resolving the brightness consistency issue through parameter optimization rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple display modes are supported, then adaptability is improved, but control complexity increases

Engineering Contradiction:
Improvedisplay mode versatilityVSAvoidexposure control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system dynamically adapts exposure conditions based on the selected display mode. Rather than having separate fixed control circuits for each mode, the controller dynamically adjusts aperture and shutter parameters according to the active mode (EVF, through-display, etc.), achieving versatility through dynamic adaptation rather than static multi-structure design.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A single system controller handles all display modes (EVF, through-display, and other modes) and both shooting types (still images and live view). This universal controller approach allows multiple display modes to be supported without proportionally increasing control complexity, as the same hardware performs multiple functions through software/control logic management.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If aperture and shutter are adjusted during live view, then exposure accuracy is improved, but image stability deteriorates due to frequent adjustments

Engineering Contradiction:
Improveexposure accuracyVSAvoidimage brightness stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The controller performs preliminary exposure determination based on the selected display mode before actual image capture. By pre-calculating appropriate aperture and shutter values for the specific mode (EVF, through-display, etc.), the system achieves exposure accuracy without needing frequent adjustments during live view, thus maintaining image stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts aperture and shutter parameters based on real-time conditions and selected mode, but once set, maintains these parameters stable during the live view period. This dynamic-initial-then-stable approach ensures exposure accuracy is achieved through initial adaptive setting, while subsequent stability is maintained by avoiding unnecessary adjustments.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2215831B1Image capturing apparatus and control method therefor
Publication Date: 2017.08.09 CANON KK
  • EP2215831B1 patent drawingFigure 1
  • EP2215831B1 patent drawingFigure 2
  • EP2215831B1 patent drawingFigure 3

AI summary

In an image capturing apparatus that is capable of selecting a display mode for live view display from multiple display modes, the difference between a measured subject brightness and an image brightness obtained from an exposure condition for acquiring live view images is obtained. Then, exposure conditions for acquiring the live view images are changed depending on a threshold corresponding to the selected display mode and on the value of the obtained difference. The image capturing apparatus allows for control of the exposure conditions for acquiring the live view images in accordance with the selected live view display mode.