Special filter with ultra flat rotary mount 45 mm for wide angle and wide angle zoom lenses especially for fast af lenses with integrated motor drive or front lens focus no vignetting dark shading of picture corners new super quality optical glass only 1 mm thick from 17 mm focal length in case of miniature photograph very low weight multi layer coating c14 seven layers of coating are vapour deposited on each side quality standard glass proclass colour of mount black impact of pictur