Hi -   Every 1st AC does it differently, and every chart and calculator (and lens manufacturer) uses a different Circle of Confusion. As a long-time 1st AC, I have my own preferences for settings, which I have used successfully for years:   16mm (& Super 16mm) 1/1000" ( 0.001")   35mm for TV (TV Series, Commercials) 1/500" ( 0.002") (for a small TV screen) 35mm for Theatre (Feature Films) 1/700" ( 0.0014") (for a large