A Diffusion Filter is a photographic accessory used to soften the light in an image. It works by scattering light rays, which helps to reduce harsh shadows and create a more flattering appearance. This effect is often used in portrait photography to enhance skin tones and create a dreamy atmosphere. In addition to photography, diffusion filters are also used in cinematography to achieve a similar softening effect on film. They can be made from various materials, including glass and plastic, and come in different strengths to suit specific artistic needs.