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.