The supplied hood is designed specifically for the KRONOR AF 75mm F1.8 Compact lens for optimum effectiveness. it should be used at all times to help prevent contrast reducing flare, provide better contrast and for added protection. +To mount the hood, align the white index mark (dat) of the hood with the white hood index mark (dot) of the lens and rotate the hood clockwise until you hear and feel it click into place. »To remove the hood, grasp it firmly and turn counterclockwise.