Exposing for the foreground will produce a washed-out, over-exposed sky while exposing for the sky will leave the foreground dark and under-exposed. Graduated Neutral Density filters are part clear, part neutral density. They allow the transition to be blended into the scene, often imperceptibly.
Tiffen Type Graduated Neutral Density
Size 67 mm
Grade .6 (2-stops)
Filter Factor Reduces ISO 1/4
Multi-Coated No
Rotating No
Effect Balanced light intensity from one part of a scene to another
Application Nature, Travel, Outdoor photography, To maintain light control, as in bright contrasty landscapes, i.e. bright sky, dark foreground
Color Temperature Not specified
Construction Water White Glass
Front Filter Thread Size 67 mm
Front Lens Cap Size 67 mm