Eventually, he stopped what he was doing and explained. I was shooting ASA speed film of 125, so that was also my starting shutter speed. When shooting completely manual the rule is simple: film speed = shutter speed + f-16. What he told me about \"plus two\" was that the rule is designed to give you an average reading for average light; since we were shooting in brighter than average light, I should increase the f-stops by two.\r\n\r\n

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