This B&W 39mm Digital Pro 486 UV/IR Blocking Filter has a completely colorless glass carrier coated with a number of extremely thin, partially reflecting layers with precisely computed thicknesses, similar to MC coating (multi-coating). The Multi-Resistant Coating (MRC) is harder than traditional B+W glass. This helps prevent scratches as well as being water and dirt repellent.
The B&W Filter 486 does not block by means of absorption, but by interference of the unwanted UV and IR radiation that is repeatedly reflected between these layers affecting the wavelengths on both sides of the visible spectrum with a steep cut-off.
B&W Digital Pro filters are characterized by a brushed chrome brass ring that will stylishly blend with today's modern digital cameras for both still and video formats.
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 and synonymous with the highest standards of filter production. It comes with a solid 10-year warranty.
The filter ring 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.
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.