The B + W 77mm 110 Solid Neutral Density 3.0 Filter has several uses and offers the possibility to achieve otherwise unachievable results. ND filters appear gray and reduce the amount of light reaching the film. They have no effect on color balance. Neutral Density filters enable the shooter to adjust exposure without affecting color balance. ND filters appear gray and reduce the amount of light reaching the film. Neutral density filters are available in 1, 2, 3, or 4 stops to suit individual situations.
Neutral Density filters permit you to create unique effects. When using high speed film in bright light, an ND filter will allow you to blur motion such as speeding cars or moving water. This permits adjustments in aperture and exposure that would normally not be possible without the filter. Determining which neutral density filter yields ideal results for any given lighting situation takes knowledge, experience and a collection of such filters. Speaking generally, the 2-stop value (ND 0.6) effectively compensates average situations.
The reputation of B+W's Schott glass is world renowned. The high production standards combined with a sturdy brass filter ring make B+W filters hard to beat. These filters have a "heft" to them that is impressive. They may feel heavier but the benefit is in the construction and results. Not only is the glass exceptional but so is the seal between the ring and glass. Schott Glass used in the manufacture of this filter is legendary andsynonymous with the highest standards of filter production.
This mount is B+Ws F-Pro mount which represents a revolution in filter mounts. The mount is thinner than previous mounts which means they can be used with wider angle lenses including most 24mm lenses on a full-frame body without fear of vignetting (dark corners on the frame). Another improvement is that the glass is no longer held in place with a front retaining ring but rather from the back.
This innovation eliminates the possibility of a hood or second filter that has been screwed in excessively tight from damaging the retaining ring. The filter ring itself is made from brass yielding a stronger product. Brass filter rings are also less prone to jamming. In addition, the seal between the glass and filter ring is exceptionally strong giving the filter added strength and durability. The Multi-Resistant Coating (MRC) is harder than traditional B+W glass. This helps prevent scratches as well as being water and dirt repellent.
In production, the filter glass is dropped into the empty filter ring from the rear and held in place with a threaded retaining ring; this is a definite advantage over a competitor who uses a spring clip to hold the glass in place.
A threaded retaining ring will hold the glass firmly and securely in place to avoid the possibility of rattling and provide perfect parallelity and flatness to your front lens element for ideal optics. The part about additional filters not binding is due to the fact that brass is a very stable metal and does not contract or expand like alloy.