The 100 x 150mm Reverse Graduated Neutral Density Kit 7 from Hitech is unique to Hitech and is innovative in its concept. With this kit, you can now control and balance the excessive brightness typically found in sunrises and sunsets since the densest part of the filter is found in the middle. In traditional graduated neutral density filters, the dense part is at the top or bottom. However, this filter is designed in "reverse" with the high density part of the graduation in the middle of the filter that then graduates to a lower density at the top.
A Reverse Graduated Neutral Density filter is especially useful to photographers who shoot landscapes early in the morning or late afternoon when the sun is lowest in the sky. Now, with these filters, you can balance out the "hot" area in the center of the image with both your foreground and sky without worrying about the center portion being washed or blown out.
The Soft/Hard designation indicates the degree of transition of the filter. Soft edge grads, like the ones in this kit, have a smooth transition from clear to ND. Hard edge grads have a more defined hard lined transition and should be used for longer lenses.
This kit contains three 100 x 150mm Reverse Graduated Neutral Density filters: One 0.3, one 0.6 and one 0.9. These filters enable the shooter to adjust exposure without affecting color balance. A Reverse Graduated ND filter appears gray and reduces the amount of light reaching either the sensor of a digital camera or the film plane of a traditional film camera. It is clear at the top with a gradual transition to darker gray at the center. Primarily, this filter is used to control exposure when shooting bright landscapes where your horizon line displays a great exposure difference between sky and foreground, and you need to balance them out for a pleasing exposure.