Lighting ratio

A 1:1 ratio means the fill matches the key and the face is lit evenly with almost no shadow, which reads friendly, clean and slightly flat. Widen it to 4:1 or 8:1 and one side drops into shadow, which reads moody and more sculpted. Most talking-head work lives between 2:1 and 4:1. You set the ratio by moving the fill or changing its power, which leaves the key exposure where it was. Beginners light both sides equally and wonder why the image looks like a video call.