Slide calculator for photographic lighting

摘要

The object of the invention is to provide a slide calculator to make the determination of flash-to-subject working distances (WD) easy and accurate for amateur and professional photographers. Light sources other than flash can be used. The calculator uses known factors such as lens f-stop, film speed, light ratio, flash guide number (GN), flash power setting and filter exposure factors to determine working distances even when using multiple flashes simultaneously. The indicia on the slides and the indicia adjacent the appropriate windows on the panels are arranged in a predetermined manner and relationship to each other to permit the desired working distance to be determined accurately. Working distances for several flashes (each flash having a different purpose) can be determined and their affect on each other is compensated for in the calculations. Then the several flashes can be used in combination to achieve a desired lighting effect with correct exposure.