These are color conversion filters for the use of daylight type color films with artificial light source. 80A increases the color temperature from 3200°K to 5500°K for the use with 3200°K lamps. 80B increases the color temperature from 3400°K to 5500°K for the use of photoflood lamps. 80C increases the color temperature from 3800°K to 5500°K for the use of clear flash bulbs.HMC-These popular filters are renowned for their ability to minimise reflection at the filter surfaces which reduces flare and ghosting. The result is an average light transmission of over 97%, giving sharp contrast and well balanced color. HOYA HMC filters are recommended for enhancing the performance of today's multicoated lenses.