Of "didymium" glass, this filter increases the color saturation of the blue spectum.
It is achieved through the selective blocking of the colors around the color being intensified.
Through this process Hoya has developed a filter that subtly increases saturation of blues and blue-greens such as sky and foliage while not giving an over-all color cast to the photograph.
The filter is most useful for photographing outdoors in noontime sun, when a circular polarizer is least effective for darkening blue sky.
Reviewed by 2 customers
With some reservations we added this filter to our kit for our trip to Lake Supperior/U.P. Michigan. There was a marked improvement over the usual 81A,B and even C. When bundled with a Tiffen polarizer Fall Colors gained some contrast and detail but the biggest gain was the Pictured Rocks National Lakeshore and the stone formations around all the waterfalls. The amount of detail, contrast, and color intensity, while not overwelming, are still closer to what my naked eye is seeing. A good bit of kitt for Landscapes. Knowing what I know now I would buy this filter again. Thanks Hoya! Thanks Adorama!
I was pretty satisfied with this product. I actually thought it might add a little more intensity but all in all it does the job.