Combining Light Sources and Using Fill-in Flash

Abstract

Often the successful use of fill-in flash is achieved only after considerable practical experience. Here formulae and their graphs are developed, in terms of exposure aperture differences, that enable the effects of fill-in to be analysed and quantified easily. Both primary and secondary effects are identified. The results are then applied to specific examples, with particular emphasis on portraits in sunlight. There is some latitude exhibited in the results, which facilitates effective control with various types of electronic flash equipment. Finally, it is shown how the results can form the basis of test sequences to establish ivorking settings and personal preferences.