Excuse me, what is a hard light source and what is a soft light source when taking pictures? thank you

Soft light source, also known as scattering light source, is the light emitted by a light source with a large luminous area, and it will not produce obvious projection when irradiated on an object. Its representative light sources are skylight and softened artificial light sources.

Hard light source, also known as concentrated illumination light, is a kind of light emitted by point light source, which can produce clear projection light on the illuminated object. Its representative light sources are mainly sunlight and lighting lamps with spotlight function. It is a kind of tough light that has not been scattered, which can often bring people a strong and energetic feeling, and has obvious directionality, which will make the subject have a strong contrast between light and dark and help to express the texture. Usually, strong light is used to describe hair, human body contour and environment.