This B+W Filter 77mm Neutral Density 0.6-4x #102 reduces the light by two f-stops (log density 0.6), and it 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 instead of a “frozen” waterfall. It has excellent color neutrality, costs less than the denser filters, and is recommended as part of a basic outfit. The filter factor is 4x.
Neutral Density filters have four main uses:
- • To enable slow shutter speeds to be used, especially with high speed films, to record movement in subjects such as waterfalls, clouds, or cars
- • To decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background
- • To decrease the effective ISO of high speed film (above ISO 400) and allow it to be used outdoors in bright situations
- • To allow cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which could cause overexposure
