How to calibrate your meter at home

I live in a rural area and get calls for jobs that never leave me enough time to get my meters calibrated professionally. I’ve devised a system that works for me in a pinch and I wanted to share it with all of you. First, you’ll need a still camera with a histogram display feature. As you know, a histogram is a digital version of the zone system. The middle of a histogram is the same as zone 5, or “middle” grey. An 18% grey card is “middle” gray in value. The idea is to expose that middle grey card to render a middle grey spike in the middle of the histogram. If accomplished, then you have achieved a perfect exposure – a feat necessary for calibrating your meter accurately.

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Spot meter 1