the 85 is primarily used to correct the color of tungsten balanced film when shooting in day-light. The 81EF helps penetrate light fog and eliminates the strong blue tone & haziness produced by UV light. The 81EF reduces blue tones in shadow areas without causing the look of an overcast sky. The 81EF can also be combined with an 85, to achieve over-correction resulting in a warm look.
The 85 remains the industry's most commonly used color conversion filter. Schneider strictly adheres to Kodak Wratten color standards.