The Tiffen 4 x 4" 85 Ultra Pol Circular Polarizing Filter combines an 85 color conversion filter with a circular polarizing filter to merge the effects of both types of filters into a single, convenient solution.nnThe 85 color conversion aspect of the filter produces a warming effect and decreases the color temperature from 5500K to 3400K, allowing the use of tungsten-balanced film in daylight conditions.nnThe Ultra Pol circular polarizing aspect of the filter helps to significantly reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. This results in a noticeable increase in the saturation of skies and foliage, as well as sharper images when shooting in hazy conditions. A circular polarizer differs from a linear polarizer in that it allows full use of a camera's autofocus and auto-exposure functions.nnThere is a total filter factor of approximately 6x, requiring a 2.6 stop adjustment for normal exposure. Tiffen filters are manufactured using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass and grinding it flat to a tolerance of 1/10,000th of an inch. This filter measures 4 x 4" / 101.6 x 101.6 mm.nnnFeatures:nn- Combination of an Ultra Pol circular polarizing filter and an 85 amber color conversion filter.n- Total filter factor of approximately 6x requires 2.6 stops of additional exposure for normal results.n- The 85 warming color conversion filter decreases color temperature from 5500K to 3400K to use tungsten-balanced film in daylight conditions.n- The polarizer helps to significantly reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface.n- Eliminates haze in distant landscapes and provides more saturated, vivid colors.n- Maximum polarizing effect when used at a 90° angle to the sun.n- Compared to a standard polarizer, the Ultra Pol design aims to increase the polarizing effect for enhanced glare reduction and greater color saturation.nnnTechnical Specifications:nn- Type: Combination of amber color conversion and circular polarizern- Size: 4 x 4" / 101.6 x 101.6 mmn- Gradation: 85n- Filter Factor: Approximately 6 (2.6 stops)n- Effect: The polarizer eliminates reflections and haze and enhances color and tone saturation. The 85 decreases color temperaturen- Color Temperature: 85: 5500K to 3400Kn- Construction: ColorCore glass