Keldan Threaded Spectrum Filter (Choose Variations)

This new and improved spectrum filter is available in several different variations. Please choose carefully which filter is best for you and please feel free to ask us for assistance in choosing the best filter(s) for your needs. These specific filters are designed for threaded mounting options. If you are looking for filters for use with the Nauticam WWL-1 check out the Keldan Spectrum Filters for WWL-1.  You may also want to consider Keldan Spectrum Filters for Rear Mounting. 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 optimize white balancing. 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 colors can be recorded naturally with a very high color rendering even without using artificial lighting.  First, choose which water color you will be using this item in; blue or green. Second, choose the primary depth you will be using this item in; 4 meters or 8 meters. **Green water threaded filters are only available in the 8 meter version** Third, choose the correct filter size for your application. If you need assistance in deciding which filter is best for you, we will be happy to assist. Without filter Due to the light absorption of the water column many colors are missing and the camera can no more recover all color after white balance. With Spectrum Filter The filter compensates the light absorption of the water column and the camera can restore all colors after white balance.   4 Meter Blue Water Spectrum Filter Color Coordinates   The Spectrum Filter SF -2 (4 meter Blue) is designed to compensate for the light absorption for all water colors and therefore provides a smooth, well balanced light spectrum to the sensor of your camera. This greatly improves the color rendering of your images and adjust the color coordinates close to daylight for outstanding results with manual white balance. The Spectrum Filter SF -2 has a compensation depth of 4m. At this depth the filter makes a perfect compensation of the light absorption of the water column. The camera then sees a daylight spectrum just like shooting at the surface. The filter is designed to provide optimal performance for any water color from blue to green water. It works best within a depth range of 2 to 15 meters. The filter has a damping equivalent to a loss of 1.5 stops. For deeper depth we recommend to use either SF -4 B (for blue water) or SF -4 G (for green water)   8 Meter Blue Water Spectrum Filter Color Coordinates The Spectrum Filter SF -4 B (8 meter blue) is designed to compensate for the light absorption of blue water and therefore provides a smooth, well balanced light spectrum to the sensor of your camera. This greatly improves the color rendering of your images and adjust the color coordinates close to daylight for outstanding results with manual white balance. The Spectrum Filter SF -4 B has a compensation depth of 8m. At this depth the filter makes a perfect compensation of the light absorption of the water column. The camera then sees a daylight spectrum just like shooting at the surface. The filter works best for blue water within a depth range of 6 to 20 meters. The filter has a damping equivalent to a loss of 4 stops. Normally low noise cameras that allow to shoot at ISO 1600 or higher are required when using this filter. IMPORTANT: If you experience problems with too low light level switch to a lighter filter such as the SF -2 (loss equivalent to 2 stops). The use of a lighter filter is always the better option than using no filter at all!   8 Meter Green Water Spectrum Filter Color Coordinates The Spectrum Filter SF -4 G (8 meter green) is designed to compensate for the light absorption of green water and therefore provides a smooth, well balanced light spectrum to the sensor of your camera. This greatly improves the color rendering of your images and adjust the color coordinates close to daylight for outstanding results with manual white balance. The Spectrum Filter SF -4 G has a compensation depth of 8m. At this depth the filter makes a perfect compensation of the light absorption of the water column. The camera then sees a daylight spectrum just like shooting at the surface. The filter works best for green water within a depth range of 6 to 20 meters. The filter has a damping equivalent to a loss of 4 stops. Normally low noise cameras that allow to shoot at ISO 1600 or higher are required when using this filter. IMPORTANT: If you experience problems with too low light level switch to a lighter filter such as the SF -2 (loss equivalent to 2 stops). The use of a lighter filter is always the better option than using no filter at all!