The B+W 62mm 0.6/4x (102) Neutral Density Filter reduces the light by two f-stops (log density 0.6) & is the most popular ND filter in photographic work. It offers many benefits, for instance f/4 instead of f/8 for selective sharpness instead of a great depth of field, or 1/15 s instead of 1/60 s for a flowing & blurred water instead of a frozen waterfall. It has excellent colour neutrality & is recommended as part of a basic outfit.