Graduated ND (GND)
Lens & optics
A rectangular or round ND filter that transitions from dark to clear across the frame, used to darken bright skies.
Three transition types: soft edge (gradual gradient, for uneven horizons like mountains), hard edge (sharp line, for clean sea horizons) and reverse (darkest in the middle, for sunsets with the sun low on the horizon). Mounted via a holder such as Lee, NiSi V7 or Kase Wolverine: a circular adapter on the lens accepts a 100mm or 150mm square filter that slides vertically. Since RAW editing and bracket merging, GND is less essential than before, but for a single in-field click it remains the cleanest solution.
Tools that help with this: