The Tiffen 4 x 5.65" 80D Colour Conversion Filter allows you to increase the colour temperature from 4200 to 5500K, enabling the use of daylight-balanced film in tungsten lighting conditions. The cooling effect of this filter requires a 0.3 stop increase in exposure for normal results. This filter is manufactured using ColorCore technology, a process that laminates the filter substrate between 2 pieces of optical glass and grinds it flat to a tolerance of 1/10,000th of an inch. It measures 4 x 5.65" / 101.6 x 143.5 mm. - The colour conversion filter increases colour temperature and provides a cooling effect. - Converts from 4200 to 5500K for using daylight-balanced film in tungsten lighting conditions. - Filter factor of 1.3 requires a 0.3 stop increase in exposure. Specifications