Hoya 62mm Neutral Density Glass Center Filter

This filter combines two curved optics, one of which is neutral density and the other is clear.

This gives the effect of a gradual fade towards the edges, with a difference of 1 stop from center to edge.

It is used primarily to give an evenly illuminated shot and remove vignetting which occurs with wide angle lenses in large format and panoramic cameras.
Available in sizes to fit today's larger wide angle lenses.