Do you want to inject the maximum amount of drama into your black & white photographs? Intersted in shooting black & white infrared film? Then use this filter. Makes blue skies really dark (almost black) and in doing so those cumulus clouds really jump out at you. For portraits it can make people look gothic and kinda eerie if you're into that. For infrared shooting it is a must-have. It limits the amount of visible light going through the lens and makes your images look more infrared-y.