The Spectrum Filter SF -4 B 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.
The filter works best for blue water within a depth range of 6 to 20 meters.
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 has a damping equivalent to a loss of 4 stops.
Normally low noise cameras that allow to shoot at ISO 1600 or higher are requried when using this filter