Can anyone offer an explanation of the use of an LLD filter? We have been using them quite frequently on this shoot I am working on, in situations where we are inside on a Tungsten stock, but lighting with daylight HMI/Arrisun coming in through the window. However when doing so we have not been using an 85 filter, only the LLD. The LLD isn't an 85 substitute is it? Any clarification on the subject would be appreciated.