The 81 Series of filters control the bluish coloration that affects daylight film. They can also remove excessive blue from the effects of electronic flash. Good for general scenics when the photographer wishes to remove the bluish cast from open shade or just add warmth to the photograph, with an 81EF having the greatest effect.
This filter combines an 81EF with a .6 (2 stops) neutral density filter.
Lee graduated neutral density filters are available with soft or hard transitions from dark to clear. The soft edge is recommended for wide angle lenses and the hard edge is recommended for normal and longer lenses. Lee graduated resin filters are 4 x 6" (100 x 150mm) x 2mm thick. The 6" length allows for adjustment of the filter within the holder.
Whereas the 81 Series of filters creates a feeling of warmth, the 82 Series creates a feeling of coolness.
81 SERIES CONVERSION FACTORS
81 decreases color temperature from 3300 - 3200 degrees Kelvin
81A decreases color temperature from 3400 - 3200 degrees Kelvin
81B decreases color temperature from 3500 - 3200 degrees Kelvin
81C decreases color temperature from 3600 - 3200 degrees Kelvin
81D decreases color temperature from 3700 - 3200 degrees Kelvin
81EF decreases color temperature from 3900 - 3200 degrees Kelvin