HD Formatt graduated neutral density filters allow the photographer to adjust exposure without affecting colour balance. Exposure can be increased by 1, 2, 3 or 4 stops to suit individual situations.

It is often necessary or desirable to balance the light intensity of one part of a scene with another. This is particularly true in situations where you do not have complete control of the lighting, such as in bright and contrasty landscapes. Exposing for the foreground will produce a washed-out and overexposed sky, whilst exposing for the sky will leave the foreground dark and underexposed. This filter allows cloud detail to be correctly retained and exposed in the image.

Soft/hard indicates the degree of transition.

- A standard set of ND filters includes 0.3, 0.6, 0.9 and 1.2. This represents a light reduction of 1 to 4 stops


Neutral density filters have four main uses

- To enable the use of slow shutter speeds, particularly with fast 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 fast films (above 400 ISO) and allow their use 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


Neutral density factors

- ND.3 (exposure adjustment = 1 stop, reduces ISO by 1/2)
- ND.6 (exposure adjustment = 2 stops, reduces ISO by 1/4)
- ND.9 (exposure adjustment = 3 stops, reduces ISO by 1/8)
- ND1.2 (exposure adjustment = 4 stops, reduces ISO by 1/16)


Formatt graduated filters are available in four types

- Soft edge - Half clear, half coloured with a soft transition to full density. Generally used with wide-angle to medium lenses
- Hard edge - Half clear, half coloured with a defined, less subtle transition. For use with long focal length lenses
- Sharp edge - Like hard edge but with a solid transition line for photographing building corners, sharp horizons or when a very pronounced transition is required
- Graduated - The graduation line is directly at the edge of the filter, so the colour change goes from top to bottom. Perfect for irregular objects and horizon lines