Features:
Control light & colour directly on your raw images at the time of shooting.
Keep the quality of your images without excessive post production work.
Create specific effects saving time on your computer.
Same filter for all your lenses by just replacing the adaptor ring.
Otate, slide, decentre in all directions for more precision & creativity.
Gradual filter is a MUST for digital users, because the digital sensor unlike film has very low exposure tolerance. Detail will be lost on both low & high light area. To correct this, you need gradual filter to balance it.