Diffusion filters soften the image. They reduce fine details as skin imperfections without affecting the sharpness of the image. Modern lenses are often so sharp, that skin does not look nice, showing every pore and winkle. Diffusion filters smooth those blemishes and create a flatten skin, providing a romantic, pleasant look, without defocusing the scene.
Diffusion filter also add highlight flare, putting a halo around blown windows, light sources, or areas of high exposure. Can also be used to reduce picture contrast by lowering white exposure, and to create romantic or period looks.
Schneider-Kreuznach offers different types of diffusion filters. Each technic providing its own effect. Classic Soft filters provide a precisely controlled soft image that is overlaid on a sharp, in-focus image. Black Frost filters mist flared highlights, tone down contrast while retaining rich blacks. Our Hollywood Black Magic® combines both: A pleasant softening of bright highlights helps control exposure while maintaining rich blacks and colors. The Radiant Soft series expands Schneider-Kreuznach diffusion filter line, bringing the ability to give skin a radiant, soft glow with a soothing effect on light skin imperfections and blemishes at the cost of very little blooming effect on highlights.
Focal length and F-Stop affect the level of diffusion. For a better control all filters come in different strength. The longer the focal length and the more light on the subject the stronger the effect.