This 49mm Yellow (Y52) HMC Filter from Hoya is designed to increase contrast on black-and white film. In landscape photography the filter would have a greater tonal separation, which would make skies look more dramatic. Some films are more sensitive than others in the blue spectrum. This yellow filter helps overcome and cut through the blue haze, resulting in a sharper image.
The glass filter has a filter factor of two, so you should increase your exposure by one stop to compensate. The multi-coating reduces reflection at the filter surface which minimizes flare and ghosting. The ring is made from aluminum and features a threaded front for adding filters.
Increases contrast and tonal separation
Ideal for landscape photography
Aluminum ring for durability
Front threads allow filter stacking