Why are Graduated Neutral Density Filters so expensive?
Some are expensive, some are very cheap. It depends very much if you think that anything over $5 is a rip-off or not. Good quality ND filters have three things in common: truly neutral coloration, high smoothness of gradation and internal or blended coloration application. Neutral coloration ensures that the filter does not impart a color cast to the image. Cheap ones often have a brown cast to them. Smoothness of gradation is important to the transition area – cheap ones can be uneven, can be darker on one side than the other, and can be speckled like the pigment was applied with spray paint. Coloration application deals with how the coloration is applied to the filter; better quality ones have the coloration blended homogeneously into the filter material or sandwiched between two clear layers. Cheap ones simply have the colorant applied to the outside of the material leaving it susceptible to scratching.
