Neutral Density Graduated filters remain, for many situations, as being the best way to balance the contrast range within a scene for landscape photographs.
This video guide demonstrates the use of a two-stop Neutral Density Graduated (GND) filter in action.
A two-stop (0.6) Neutral Density Graduated filter from the Cromatek 100 Series
What we actually 'see' is our mind's reconstruction of how light falls on / interacts with/ reflects/ or is absorbed by objects - based on input provided by the eyes — not the actual light received by our eyes. Our eyes and brain have the ability to interpret varying levels of light and shadows within a scene over a much greater dynamic range than can exceed a single image made with a camera.
In scenes with a notable dynamic range (a large difference between the brightest and darkest parts) - it is likely that parts of the image will either be overly dark or highlights 'washed out', details of form and texture being lost in both cases in the case of a single exposure. Photographers have the option of using Graduated Neutral Density (GND) filters.
In the video below a 2-stop GND filter is used to balance the difference between the sky and the land to compress the dynamic range observed (which would exceed the camera's capabilities) into a single photograph.
The field and sky have a dynamic range comparable now to the view one would see through our eyes, having used a 2-stop GND filter and a Sigma 10-20mm lens
The Cromatek 100 2-stop GND filter used in the video (and photograph) examples above have a semi-soft transition. The transition rate of a GND filter describes how quickly it goes from clear to darker tones.
Afterglow side-light in the same field on a summer evening. Using a 2-stop GND filter once again, with a wide angle lens (10-20mm Sigma lens)
Especially with wide-angle / ultra wide-angle lenses, it's worth taking care to avoid glare on filters by shading the filter holder slightly - in situations (such as the afterglow photograph above) where there is a notably brighter patch of the sky. This can be done by using your hand on the brighter side (make sure not to wobble the tripod!) or as I often do, to use a broad rimmed hat as a shade, which has a much bigger area than your hand.
Hard transition GND filters are very good where there is clear horizon, such as: wide coastal vistas, moorland plateaus, prairies. Hard transition GND filters are not ideal in compositions such as jagged mountain scenery or tight coastal coves, where rock formations standing above the transition line may be overly darkened.
Soft transition GND filters are more forgiving for most situations, though on very wide angle lenses it can be occasionally challenging to match the transition zone to the horizon.
Graduated filters aid local contrast such as giving clouds more definition too by improving colour and detail.
GND filters can also be inverted, for occasions such as strong transient sidelight illuminating the land under a moody, brooding ominous sky.
The British designed Cromatek 100 filters, created by Spa Photo can be purchased direct from the link button below.