A 52mm Hoya FL-W Fluorescent Hoya Multi-Coated (HMC) Glass filter is used to balance daylight film under warm white or white type fluorescent lamps. NOTE: The FL series of filters alone does not always guarantee 100% correct color balance when shooting under fluorescent lighting. They are general purpose filters intended for moderate correction and will not, by themselves, necessarily provide perfect color rendition. An FL-D Fluorescent Glass filter is used when you wish to correct for the greenish tone that appears when shooting daylight film under general purpose fluorescent lighting. An FL-B filter is used to correct the color balance when shooting tungsten film under fluorescent lighting.