The Tiffen 138mm Soft Contrast 4 Filter is a contrast reduction filter that darkens highlights while maintaining the density of shadows within a scene. The effect of a light absorbing element within this filter is apparent in highlights without requiring a change in overall exposure. Details within bright areas are made more visible without a similar effect on dark areas. Tiffen Soft Contrast filters are available in grades numbering one through five. Each larger numbered grade corresponds to a stronger effect.
This filter is made using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass, grinding flat to a tolerance of 1/10,000th of an inch, and then mounting to precision metal rings.