The B+W 40.5mm UV/IR Cut MRC 486M Filter is an ultraviolet and infrared control filter that is useful for digital cinematography as well as still photography. While recording video with a CCD or CMOS camera, multi-stop neutral-density filters are used to maintain proper exposure by compensating for increased light levels when widening the camera lens's iris to obtain a narrower depth of field. As the increased amount of light passes through multi-stop neutral-density filtration, visible light is progressively blocked, while infrared light is allowed to pass through. As the proportion of infrared light that reaches the sensor of a camera being used for digital cinematography becomes greater, the results can show unwanted color shifts, particularly in dark areas of the frame such as shadows where the appearance of black is dominant.
When the B+W 40.5mm UV/IR Cut MRC 486M Filter is applied, 88% of ultraviolet light waves are blocked at 380 nanometers along with 95% of infrared light waves at 700 nanometers, helping to ensure that light falling on a digital camera sensor is limited to the visible spectrum. When used along with multi-stop neutral-density filters while recording with a digital sensor, potential infrared color shifts are prevented or minimized, preserving color accuracy throughout the frame. This filter may also be used to help ensure that the appearance of unwanted blue casts is reduced while recording digital video or still photos under daylight that also features intense ultraviolet light.
The front surface of a B+W 40.5mm UV/IR Cut MRC 486M Filter includes thirty layers of interference coatings which allow it to limit the light that falls on a digital camera sensor to the visible spectrum. When combined with a wide-angle lens, lower-frequency wavelengths of visible light associated with yellow, orange, and red colors passing through the filter and along that lens type's curved edges can be impeded in a significantly greater degree than higher-frequency wavelengths of visible light associated with blue and violet colors. This can result in an unwanted cool cast along the edges of an image taken with a B+W 40.5mm UV/IR Cut MRC 486M Filter and a wide-angle lens. To avoid such color shifts along the edges of an image when using this filter, it is recommended not to be used with lenses that are intended to provide an angle of view greater than 60°.
Eight layers of anti-reflection coating are included on the rear glass surface of this B+W 40.5mm UV/IR Cut MRC 486M Filter. This Multi-Resistant Coating (MRC) prevents internal ghosting and reflections, offers protection to the filter substrate, and helps its rear surface to stay clean for longer than with uncoated filters.
B+W filters are constructed from Schott glass for increased optical clarity and color fidelity. The B+W 40.5mm UV/IR Cut MRC 486M Filter features an F-Pro brass filter ring for durability and jamming prevention, as well as 40.5mm front filter threads that allow it to be paired with other filter types. When in use, but not combined with another filter that provides a specific effect, it is recommended to place a clear, protective filter over the B+W 40.5mm UV/IR Cut MRC 486M Filter to prevent damage to its front interference coatings.