Putting NiSi Filters to the Test
A couple months ago, I was approached by NiSi Filters, asking if I was interested in testing a few of their neutral density filters. I eagerly accepted, because I was never fully satisfied with the 10-stop filter I currently have, and well, who would say no to testing new filter technology?
Before I get started in reviewing the filters, I'd like to disclose relevant information and clarify the arrangement. NiSi did send me two filters and their holder/adapter system at no charge, for the purpose of testing and reviewing. No agreement was made that I was to say specific things in my review. Nobody has seen this review prior to my publishing it, and I do not owe anyone any favors in writing it. If I enjoy the filters, there is a possibility that I might promote them to other photographers in the future as part of a relationship with the company -- but no such relationship exists at this time.
For those who may be unfamiliar, ND is short for neutral density filter, which filters out all wavelengths of light at (ideally) an equal ratio so it increases the exposure time without adding unwanted color casts to the image. This can create highly desirable effects from otherwise mundane or difficult scenes, such as moving water or clouds while the sun is up. Without an ND filter, it would be difficult, if not impossible, to achieve camera settings that would produce silky water, streaking clouds, and other long exposure effects, during the day and around sunset. (Try it yourself: can you get a proper 10-second exposure in the middle of the day at your favorite beach or waterfall?) This is when ND filters come into play: they allow you to drastically cut the amount of light that enters the camera, so you can achieve those long exposures when they would otherwise be impossible. In many cases, it is impossible to mimic the effects of an ND in post processing; it may be possible to fake streaky clouds, but it is not possible to fake a long exposure on a waterfall, flowing fog, etc.
In recent years, I have not been shooting very much with filters, because they have become a pretty big hassle to carry around, store, and use, and the various color casts are difficult and irritating to correct. The NiSi system has been a breath of fresh air: well-built, easy to use, and minimal color casts. I can easily see myself shooting very often with these filters.
Prior to the NiSi ND filters, I primarily used the Lee Big Stopper (10-stop ND,). The Lee, while around the same price as the NiSi, is known for a strong blue-green color cast, which is an annoying part of using just about any strong ND filter that doesn't cost more than a dSLR. While it is possible to correct color casts in post processing, strong ones can be difficult, and while there is a Photoshop trick that can work well, it doesn't work on smart objects, which are an essential part of my Photoshop workflow.
In short, here's what I found:
The NiSi 10-stop ND filter has zero noticeable color cast. To my knowledge, there is no other filter at or near its price point with no color cast.
The 6-stop filter has a slight magenta/red cast. It is easily corrected with a couple sliders in Lightroom/Camera Raw. As of this writing, the company said they are working on fixing the magenta cast; when I can verify it has been fixed, I will adjust my review.
The holder and adapter rings are great, well-built and easy to put on/take off. The circular polarizer that comes with the holder is a nice touch. I noticed no vignetting or artifacts at my widest lens (16mm on my Canon 16-35 f/2.8L II). The holder works extremely well; I had no issues with light leaks, which I cannot say about my old setup. (Light leaks can be quite the pests with strong ND filters, so it's important to find a holder that doesn't allow any.) Everything comes with a nice case, and the filters are stored in an elegant, hard-sided case.
I found no noticeable loss of image quality with the filters on.
It is certainly possible to get the best of both worlds by blending multiple exposures of various shutter speeds with the NiSi filters; for example, for the Athabasca Falls series above, I prefer the water motion I got with the 6-stop and the sky from the 10-stop. I could blend those two exposures together into a final image, making use of both filters. I've found myself using both filters fairly often; which one is best for you depends on your desired use. The 10-stop is often too much for shooting right around sunrise/sunset, when the 6-stop is often perfect. But the 10-stop is excellent for showing cloud movement, and other things that require very long exposures.
Without hesitation, I would recommend the NiSi filter system to any landscape photographer. I no longer have any use for my Lee Big Stopper, as its color cast is extremely strong in comparison; and the NiSi holder (version 5.0) blows my Cokin holder out of the water in durability, light sealing, and lack of vignette at wide angles. The slight red cast on the 6-stop is easily correctable in post, and the 10-stop with no color cast is an excellent addition to any landscape photographer's bag.
Note: The images in this post are all processed in Lightroom/Photoshop. Some of them are blends of multiple exposures from the same shoot, but for the images shown in sets, I used essentially the same process for each of the images. This ensures that the filter is the primary variable.