A good quality filter kit is one of an essential tools for any landscape photographer. It not only gives the extra scope of creative expression, but also provides the freedom for in-camera improvisation. As a landscape photographer, I have always been a big fan of filter system because they have always surprised me with the dramatic output. I started with Hoya and immediately shifted to B&W and I own them for almost a 7 years. When I first got an award for one of my picture with a 1000x Neutral Density filter, people assumed that the picture was manipulated in Photoshop. It was hard to believe in them that a 10 stop Neutral Density can create such a wonderful result. Since then, a 10 stop Neutral Density has been a great companion and I am not afraid to use it in any situation. However, one little issue I had with my B&W system was the color cast ,which I used to get in all my images. Color correcting those images had become an additional process in my workflow. When I was approached by NiSi to use and review their NiSi Nano IR ND 1000 (3.0) 150X150 mm filters, I was not very sure whether it will solve the issue of color cast which was pretty apparent in B&W.
First Impression: I must admit the first impression was top class. Absolutely professional. The filter was very delicately packed inside a nice pouch. A booklet containing the information regarding the use of filters was quite handy and informative. Along with the filters, NiSi also sent me a nicely made hard case which can carry up to 6 150X150 mm filters. It is hard enough to take my mind away from transit breakage during my travel.
Technical Specification: NiSi claims that their Nano IR ND 1000 (3.0) 150X150 mm filter has a super multi coating (Water-proof, Anti-Scratch, Stain resistant) and low reflection attenuation nano coating on both the side of the filters to prevent it from physical damage and light reflection. Let me tell you, it’s a high standard optical glass, not resin. Therefore, there is negligible chance of sharpness loss.
Performance: Without going into many technical details, let’s use it on the field and analyze. I have been using B&W ND 1000X for quite some time. There was a distinct issue of color cast. It is said that the color cast is because of infra-red colors and you will find plenty of blogs on the internet on how to get rid of color cast in ND filters. Over a period of time I developed a habit to carry a gray card and match the colors from a picture taken without the ND filter at the same location.
When I started using NiSi Nano IR ND 1000 (3.0) 150X150, I was surprised by the fact that it had no color cast. It was hard to believe; hence I tried it in a different situation. And I must admit that I am yet to notice any prominent color cast in any of the images. 
Sharpness depends on many factors, particularly in long exposures. However the loss of sharpness was difficult to notice in any of the images. This is because of the high quality glass. Therefore, my recommendation would be to spend extra bit from your pocket rather than compromising on the image quality.
Here are some more samples of images taken using NiSi Nano IR ND 1000 (3.0) 150X150. Some images are color graded in post therefore some amount of color tone will be apparent.
Handling: One of the biggest challenges of using a ND 1000 (3.0) is to compose and to focus your image, while the filter is mounted on your lens. Since it reduces the light by 10 stops, you can hardly see through anything. Therefore the best way to use ND 1000 (3.0) is to compose, focus and then mount the filter on your lens. Slides-on filters are always handy in such situation. The filter I am using is 150X150mm square filter. Therefore a filter holder is required to use this filter. The filter holder provided by NiSi is made out of high quality aviation graded aluminium with matt black anti reflective coating. It can hold up to 3 filters and is very easy to install.
The hard case provided by NiSi can carry up to 6 filters and hard enough to secure your filters while traveling. It is made out of PU leather.
Using a 10 stop Neutral Density is always a delight. And for a landscape photographer it becomes an essential tool to smoothen the rough water or to give a nice blurry effect of the moving clouds. While finalizing a 10 stop Neutral Density one has to be very particular about the color cast as well as the sharpness. There are many cheaper options are available in the market. However, the quality of the image should be the top priority for any photographer, hence spending extra bit on a quality product like NiSi Nano IR ND 1000 (3.0) is strongly recommended.
