The Tiffen 138mm Mounted Warm Soft/FX 4 Filter can be applied to create a warm cast over an entire image while purposely reducing the appearance of blemishes and wrinkles in portraits, or to apply a general soft-focus effect while maintaining overall sharpness. An array of small lenses distributed within the surface of this filter smooths fine lines and textures, which can be useful for creating a more flattering result of a subject.