sky = +5, foreground = 0
0 means exposed correctly.
means ur sky is blown (most of the times), unless u have a good DR, then u can get detail there, but its still bright. u can pull down in photoshop though if the details are there.
but if ur camera cant get the details... its gonna read as white. so u need lets say a 5 stop ND. so ur result becomes
sky=0, foreground=0. and u expose nicely.
but sky can change. it can just be +3... if i only have +5, end up my sky darker than foreground...
you can rent my 77mm B+W ND110 for $20 a day. step-up rings are provided