This is the classic filter for architectural photography. White façades glow brightly, the blue sky is darkened dramatically and clouds become more impressive. It is also excellent for spectacular landscape photographs with greatly improved distant views. Its filter factor is approximately 5.
MRC (Multi-Resistant Coating) by B+W is not only an extraordinarily effective multiple layer coating, it is also harder than glass, so that it protects filters from scratches (for instance when cleaning the filters), and it is also water and dirt repellent, thus facilitating filter maintenance.