

A small or distant light source makes dark shadows with sharp edges (hard). A large, wide light source makes shadows with soft, blurry edges (soft). Hard light gives tension; soft light feels comfortable and upscale.
Soft for beauty, portraits, and food and beverage ads. Hard for midday outdoors, thrillers, sports, and punchy product shots.
Public AI example available — The Sora 2 guide compares 'soft, warm key' with 'single hard light with cool edges', and Veo has 'harsh fluorescent office lighting'
A woman stands beside a window, it begins in soft diffused light with gentle shadow falloff and flattering skin, then a curtain pulls open and a single hard beam of sunlight cuts crisp sharp-edged shadows across her face, locked-off camera, 85mm lens, calm mood turning dramatic, 6-second shot.
soft diffused window light, gentle shadow falloff, flattering skin · single hard light, crisp sharp-edged shadows, high contrast
StudioBinder — Hard Light Explained (No Country for Old Men and Her examples)