Automatic optimization of photographic exposure parameters through

Abstract

Exposure control apparatus and methods for use in a photographic camera to improve the overall quality of photographed images over that obtainable by adherence to ISO/ANSI exposure standards. The quality improvement is attained through automatic selection of photographic exposure parameters primarily based upon scene requirements (including providing sufficient depth-of-field and avoiding image blur) and film exposure characteristics, rather than through use of the ISO/ANSI exposure standards. Specifically, the present invention: (a) determines the initial exposure settings, e.g. shutter speed and lens aperture size and, where appropriate, flash parameters, necessary to provide a baseline, typically an ISO normal exposure of a scene to be photographed; (b) ascertains corresponding exposure settings (and, where appropriate, flash parameters) that actually meet the scene requirements, such as e.g. camera shake and required depth-of-field; (c) assesses, in response to differences between the initial and corresponding exposure settings, whether any extra system speed exists and, if so, the amount of extra system which is available for use in photographing the scene; and (d) finally, where possible, properly utilizes that extra system speed in a pre-defined prioritized incremental manner to vary the baseline exposure settings (and, where appropriate, flash parameters) in order to provide an exposure of the scene that produces the desired level of image quality. As such, the invention deviates from the ISO/ANSI exposure standards where necessary to improve image quality beyond that which would result from adherence to these standards. Ambient, fill and full flash lighting conditions are all advantageously accommodated.