This filter is available for use with Nauticam's Wet Wide Lens 1 (WWL-1)
KELDAN Spectrum Filters are scientifically engineered red filters based on spectral measurements of the lighting conditions underwater. KELDAN Spectrum Filters convert the ambient light into a daylight spectrum in order to restore correct colors and to optimise white balancing.
The Spectrum Filter D2 for deep water converts ambient light to white light within a depth range from about 7 to 15 meters.
The filter characteristics are carefully adjusted not only to balance the RGB color channels but also to correct for a very smooth spectrum with excellent color rendering capabilities. When using the Keldan Spectrum Filter at depth, the color coordinates will be shifted to the white light region. Therefore colours can be recorded naturally with a very high color rendering even without using artificial lighting.
Keldan Spectrum Filters are available in three different grades, optimized for three depth ranges.
The above diagramm shows the color rendering capability of the different filters versus the depth.
The above CIE color coordinates diagram shows how the color coordinates of the ambient light are shifted to the region of white light. A perfect match with daylight is at about 12m depth. At this depth the color coordinates of the filtered light corresponds to a color temperatrue of about 5600 Kelvin.