| 摘要 |
There is disclosed herein a slide calculator for determination of flash-to-background distance for studio photography when using color filters over the flash. By use of the calculator, known factors, such as lens f-stop, film speed, flash guide number (GN), background density (darkness), desired degree of color (including shades of gray and white) saturation of said background and filter exposure factors can be used to determine the working distance of a background-flash with a color filter over the flash. An electronic flash meter is not required. The calculator includes a front panel with a window-like aperture and a back panel. Two slide members are positioned and movable between the front and back panels. Indicia is provided on the front panel and is generally arranged adjacent the window like aperture. Indicia is also provided on the slide members and is arranged for exposure at the window. In connection with distance to be determined, the indicia on the slides and the indicia adjacent the window are arranged in a predetermined manner and relationship so as to permit the distance to be calculated. Photos or slides showing how various color filters will photograph in various shades provides a visual aid in choosing a color and shade and is used in conjunction with the slide calculator to determine the flash-to-background distance required to reproduce said color and shade. |
