Heliopan 39mm Digital UV and IR Blocking Glass Filter.
Heliopan Digital Filter.... This filter has been especially designed for imaging with digital sensors. Since they have a significantly higher sensitivity in the IR area then film material, it blocks both disturbing UV and IR light. The result is improved color separation and sharpness.
The UV protection blocks UV radiation in daylight. In addition colors are improved especially in the blue and red channels. Since artificial light contains especially high IR radiation the filter ensures better control of the blue channel. This dichroic coated specialty filter should not be used with extreme wide angle lenses.