The Tiffen 4.5-inch round 1.2 neutral density (ND) filter has multiple uses and offers the ability to achieve results otherwise impossible. It allows the photographer to adjust exposure without affecting colour balance. ND filters appear grey and reduce the amount of light reaching either a digital camera's sensor or the film plane of a traditional camera. Neutral density filters are used to create unusual special effects such as capturing the "blur" of rippling waterfall water or the swirling effect of city traffic. Tiffen's ColorCore glass is produced by a process that involves permanently laminating the filter material between two pieces of optical glass polished to tolerances of one ten-thousandth of an inch, then mounting them in precision aluminium rings. Determining which neutral density filter yields ideal results for a given lighting situation requires knowledge, experience and a collection of such filters. Neutral density filters have four main uses - Allow the use of slow shutter speeds, particularly with high-sensitivity films, to record movement of subjects such as waterfalls, clouds or cars - Decrease depth of field by allowing the use of wider apertures, which helps separate subjects from their background - Decrease the effective ISO of high-sensitivity films (above 400 ISO) and allow their use outdoors in bright situations - Allow cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which could cause overexposure ColorCore Technology Tiffen filters are manufactured using ColorCore technology, a closely guarded proprietary process that involves permanently laminating the filter material between two pieces of optical glass polished to tolerances of one ten-thousandth of an inch, then mounting them in precision metal rings - The ColorCore process allows Tiffen to control the colour and density of their filters, as well as the characteristics of special effects filters with precision far superior to typical mass-tinted filters, which generally exhibit colour and density variations Superior Quality Hollywood's largest film studios rely on Tiffen filters for their multi-million-pound productions. Superior quality and design make Tiffen the preferred choice of filmmakers, professional photographers and even NASA - Tiffen has also received an Emmy from the Academy of Television Arts and Sciences for its engineering excellence Specifications: - Type: Neutral density filter - Size: 4.5-inch round - Grade: 1.2 - Filter Factor: 4 stops - Effect: Use high ISOs in bright light - Application: Nature, travel, outdoor photography - Construction: ColorCore glass