Hard Edged Neutral Density Filter Set from Formatt Hitech
Neutral density (HE ND grad) filters are colourless filters that remove light evenly across all spectrums. Neutral density filters are used to lengthen exposure time, or allow the shooter to use a larger aperture. Common uses are:
Creating shallow depth of field during daytime
Making water appear misty and ethereal
Removing people from busy areas
Transforming clouds and skies
Adjust exposure on cinema cameras because shutter duration is fixed
ND filters are available between 1-10 stops of density, plus 13 & 16 stops for long exposure. The density of the ND is written either in the number of stops, or using the traditional density scale.
0.3 = 1 stop
0.6 = 2 stops
0.9 = 3 stops
1.2 = 4 stops
Be careful to note the difference. For example, a 6 stop filter could be labeled “1.8”, but a two stop filter could be labeled “0.6.”
So 3-4 stop ND filters – ie 0.9 and 1.2 allow street photographers to shoot their fast lenses “wide-open” even during the middle of the day.
Graduated filters (or more simply ‘grads’) have the effect on half of the filter. The most common use for a graduated filter is to reduce the luminosity of a bright sky balancing it to the terrain below. The advantage of using a grad filter, rather than HDR techniques is a far more neutral color representation than the “candy rainbow” side effect resulting from HDR processing. Plus, it’s far more authentic and satisfying to create a great image with a single exposure, and far less work in post processing too.
Hard Edge Grads feature a defined transition between the clear and effect. These filters are ideal for reducing luminance of the bright sky over a defined horizon line, such as a seascape. Hard Edge Grads are an essential tool for both fine art photographers and professional cinematographers alike.