The PROND100000 has a 16 3/5-stops light reduction equal to a ND density of 5.0 and 0.001% transmission factor.
The ACCU-ND technology in the HOYA PROND filters yields a truly neutral color balance that will not add any noticeable color-cast to your images. A neutral density filter of Pro ND100000 becomes additionally in this series.
HOYA PROND 100000 is a high concentration filter of 100000 times of filter factor. By the highly precise vapor deposition manufacturing method, the extremely neutral nature is high and it's most suitable to take a picture of the sun.
On the occasion of photography, please shade the light in the finder side.
Of course you can use it under the fine weather and, as well as sun photography, can get long exposure more than an ND1000 filter.