The Heliopan 28mm KB-6 (80C) Filter is a color conversion filter that helps to increase the color temperature from 3800 to 5500K. The 80C allows you to use daylight-balanced film in tungsten lighting, but does not fully correct to 3200K, resulting in warmer colors when compared to an 80A or 80B filter.
There is a 2x filter factor with this filter, requiring an increase of 1 stop for normal exposure. It has a 28mm brass mounting ring that is painted a matte black to help reduce reflections. The SH-PMC multi-coated Schott glass provides greater contrast and reduced reflection compared to uncoated filters.
