HD Formatt graduated neutral density filters allow photographers to adjust exposure without affecting colour balance. Exposure can be increased by 1, 2, 3 or 4 stops depending on the situation.

It is often necessary or desirable to balance the light intensity between different parts of a scene. This is particularly true in situations where you don't have complete control over lighting, such as in high-contrast landscapes. An exposure for the foreground will produce a washed-out and overexposed sky, whilst an exposure for the sky will leave the foreground dark and underexposed. This filter allows cloud details in the image to remain properly exposed.

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 allow the use of slow shutter speeds, particularly with high-speed films, to record the movement of subjects such as waterfalls, clouds or cars
- To decrease depth of field by allowing the use of wider apertures, which helps separate subjects from their background
- To reduce the effective ISO of high-speed films (above 400 ISO) and allow their use outdoors in bright situations
- To allow film and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes that 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 smooth transition to maximum 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
- Razor Edge - Like hard edge but with a solid transition line for photographing building corners, sharp horizons or when a very pronounced transition is required
- Blender - The graduated line is located on one edge of the filter so that the colour change occurs from top to bottom. Perfect for irregular objects and horizons