Mechanical Shutter Curtain Control for Uniform Flash Exposure
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Solution Overview
Problem
Existing image capturing apparatuses experience exposure variation between the upper and lower areas of an image during flash photography due to differing travel speeds of the front and rear curtains, leading to inconsistent lighting across the frame.
Innovation Solution
The apparatus selectively controls the travel speeds of the front and rear curtains to be the same or the front curtain to be faster than the rear curtain, based on shutter speed, to minimize exposure variation while shortening flash synchronization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the traveling speed of the front curtain is always made shorter than the traveling time of the mechanical shutter of the rear curtain to advance the light emission timing, then the flash synchronization time is shortened, but the charge accumulation time always differs between the upper and lower areas of the captured image, causing exposure variation
Solution Approach 1:
The patent applies dynamics by making the shutter system adaptable and changeable rather than fixed. The control unit dynamically adjusts the traveling speeds of the front and rear curtains based on the determined shutter speed, switching between different speed relationships (same speed or front faster than rear) to optimize both flash synchronization time and exposure uniformity for different shooting conditions.
Solution Approach 2:
The patent changes the parameters of curtain traveling speeds based on the determined shutter speed. The control unit modifies the speed relationship between front and rear curtains according to the specific shutter speed required, thereby adjusting the charge accumulation time to be substantially equal across different areas while still shortening flash synchronization time when needed.
2Speed
If the traveling speed of the front curtain is made higher than the rear curtain to shorten flash synchronization time, then the flash synchronization time is reduced, but the charge accumulation time varies between upper and lower areas causing exposure variation
Solution Approach 1:
The system dynamically adjusts the speed relationship between curtains based on the determined shutter speed. Rather than always making the front curtain faster, the control unit selectively applies different speed configurations (same speed or front faster) depending on the specific shutter speed requirement, thereby maintaining exposure consistency while achieving flash synchronization speed when needed.
Solution Approach 2:
The control unit changes the traveling speed parameters of the curtains based on the determined shutter speed. By adjusting the speed relationship between front and rear curtains according to the specific shutter speed, the system optimizes both flash synchronization performance and exposure uniformity for different shooting conditions.
3Manufacturing precision
If the front and rear curtains travel at the same speed, then the charge accumulation time is consistent across the image, but the flash synchronization time is not shortened
Solution Approach 1:
The system dynamically switches between same-speed and different-speed configurations based on the determined shutter speed. The control unit selects whether to make the front and rear curtains travel at the same speed or at different speeds (front faster) depending on the specific shooting conditions and required shutter speed, thereby balancing exposure uniformity and flash synchronization time.
Solution Approach 2:
The control unit changes the traveling speed parameters based on the determined shutter speed. By selectively applying same-speed or different-speed configurations according to the specific shutter speed requirement, the system achieves both exposure uniformity and optimized flash synchronization time for different shooting conditions.
Data Source
AI summary
An image capturing apparatus capable of reducing exposure variation in opposite end areas of an image when photographing is performed with flash light emission while shortening a flash synchronization time. A system controller determines a shutter speed for flash light emission photographing. The system controller selectively executes first control for controlling a traveling speed of a front curtain of a shutter and a traveling speed of a rear curtain of the shutter to the same speed, and second control for controlling the traveling speed of the front curtain to be higher than the traveling speed of the rear curtain. Before flash light emission photographing is performed, the system controller determines which of the first control and the second control is to be adopted according to the shutter speed.