This is my first post on this forum so moderators please move it to the most appropriate thread category, if this isn't it. Thank you. I shoot with an Argus C3 brick 7 speed 1/10-300 F3.5-16 Coupled Focus. I understand the Sunny 16 rule, and want to know if there is a way of making some kind of reference chart. I pulled out my digital camera to do metering (Olympus PEN) and using basic arithmetic, I came up with this chart. Assuming ISO 200 for all. Br't Sun - F16 - 1/200 sec F11 - 1/400 sec ETC Sun - F11 - 1/200 sec F16 - 1/100 sec Hazy Sun - F8 - 1/200 sec F16 - 1/50 sec ETC I want to know if there is some other formula.