Light modifiers are tools used in photography and videography to alter the quality, direction, and intensity of light. They help create different moods and effects by softening harsh light, controlling shadows, or adding color. Common types of light modifiers include softboxes, umbrellas, and reflectors. These modifiers can be attached to various light sources, such as flash units or continuous lights. By using light modifiers, photographers can achieve more professional-looking images, enhance the subject's features, and create a more visually appealing composition.