Cavision 3 x 4" Grad Blue Resin Filter

This Cavision Grad Blue Resin Filter is compatible with filter holders that can accommodate 3 x 4", 2mm thick 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.