Hi all,
Is the full, 1/2, 1/4 an internal reference using the full Lee diffusion as the baseline?

or

Is a Lee full diffusion equal to a full stop of light loss, a 1/2 equal to a half stop, etc...?

Looking at the Lee Filter site (UK version USA Version not up yet) Full 216 looks like 1 1/2 stops, Half White 250 has 3/4 stops, Quarter White 251 is 1/3 of a stop so it is not exactly linear. 2 Quarters don't exactly equal a half although 2 halfs equal a whole and they don't start at one stop. HTH

www.leefilters.com

Does immensely - thanks Daniel!