Choosing a Filter System
Using a filter holder rather than a circular screw-in filter allows you to make a single filter purchase that is used across a variety of lenses. 85mm filters are an excellent choice for small mirrorless camera systems such as Leica M and Micro Four Thirds systems, or DSLR users with small lenses. The 100mm system is an excellent all-round choice. 100mm filters are popular for DSLR photographers and DSLR cinematographers using larger, more expensive lenses. Typically, most solid filters are square. Graduated filters are rectangular to allow for vertical adjustment of the horizon
Neutral Density (or ND) filters produce a grey neutral effect and are used to reduce light in photography, enabling more control over exposure and depth of field without affecting color or contrast. NDs are made in different densities according to the level of light reduction from 1/3 to as much as 10 Stops of light. ProStop filters are a specialist range of high density NDs used to create motion blur in long exposure shots and can help create startling effects in water, cloud and other moving objects. The range is available in densities from 6 to 10 Stops. ProStops include a foam gasket which sits between the filter and the holder to help eliminate light leakage.