Cavision 4 x 4" Soft-Edge Graduated Blue 0.9 Filter (3-Stop)

The Cavision 4 x 4" Soft-Edge Graduated Blue 0.9 Filter is compatible with filter holders that can accommodate 4mm-thick, 4 x 4" rectangular filters. It can be used to add blue to a hazy or colorless sky. When used instead of a polarizer filter to enhance the sky within an image, the desired effect can be applied only to the sky, without any unwanted polarization or additional contrast to any part of the image. The filter is densest at the edge and tapers to clear by the middle, with a soft-edged line of transition between the dense and clear areas. This filter has up to a 0.9 density and reduces light from entering a lens by up to three stops.