Fstoppers Reviews the Haida NanoPro Interchangeable Magnetic Variable ND Filter

A neutral density filter has probably found its way into almost every photographer’s bag at some point. Variable ND filters can make the process of working with ND filters much simpler in certain situations. Today, we’ll look at a quality, and somewhat different, option from Haida, the NanoPro Interchangeable Magnetic Variable ND. 

What’s in the Box?

When you first open the box, it may seem a little confusing. There are actually two smaller boxes with three separate filters, and an additional lens cap, inside. This is what makes Haida’s NanoPro Interchangeable Magnetic Variable ND Filter (what a mouthful!) stand out from the crowd. While plenty of variable ND filters claim to vary from 2-10 stops or beyond, Haida has split the filter into three different pieces that can easily be changed to improve image quality.

Construction

The first piece of the system is the filter you screw into your lens. It has a filter thread of your choice (from 58-82mm) on one side and a magnetic ring on the other. The additional two pieces (a 2-5 stop ND and a 6-9 stop ND) magnetically attach to the front of this filter. They are easy to align, as there is a notch and groove system that provides hard stops at each end of their ND ranges. The glass used in these filters is Haida’s NanoPro glass. While not their top-of-the-line Red Diamond glass (more durable), it is still optically excellent. We’ll talk more about that below. 

The filter rings are made from aluminum, which is lightweight but does not screw in as nicely as something like the brass that B+W uses. Like many filters, this just means needing to be a little more careful as you start to screw them in. I’ve also found that it can slip a little when turning the front filters if not tightened carefully. In my experience, it’s been best to use two hands when changing the strength of the filter. 

In Use

The first thing I noticed as I started working with these filters was the hard stops at each end of the ND range. This is extremely useful if you need to make a quick change from minimum to maximum light blocking without looking. It also makes sure that you don’t turn the filters too far and potentially bring out unwanted artifacts. 

Actually turning these rings is reasonably easy as the magnets are strong enough to hold the filter securely, but not to hinder you when changing their strength. The inner filter remains still while you turn the outer filter to alter the ND strength, just like a regular variable ND filter. Turning the attached outside ring requires you to hold the thin aluminium ring and twist. This can be tough with cold fingers or gloves and would possibly have benefited from having a small tab on the ring to make it easier, much like those on Haida’s other variable ND filters. This would also make the removal of the outer filter easier. 

While having separate pieces of glass for weak and strong ND settings means higher image quality in the end, it does also mean that there are now six sides of glass to keep clean rather than the two of a traditional variable ND. Keeping a cleaning kit around and being careful not to cover any of the pieces in fingerprints are must-follow rules for this system. 

Optical Quality

As we’ve come to expect from Haida, the glass used in this filter is of great quality. While using it, I didn’t notice any loss in detail. Images come out just as sharp and contrasty as without the filter. I did notice a slight warm cast to the images, especially when using the 6-9 stop filter. In the real world, it was barely noticeable and when shooting a color chart, I noticed only around 100 Kelvin difference from my control image. 

The major benefit of using this split ND filter is that the dreaded X pattern that is present with a lot of filters that try to have extreme ranges is completely absent. When it comes to vignetting, Haida guarantees that there will be little or no vignette down to 28mm when using the 2-5 stop attachment and down to 35mm when using the 6-9 stop attachment. Even then, a vignette is only visible at the strongest end of the range. That being said, this is certainly not the tool for those who use lenses of 24mm or wider. For everything else, however, this is a really useful kit.

Who Is It For?

It seems that Haida is squarely aiming at hybrid video and stills creators with this kit. The 2-5 stop filter is a useful range for video and 6-9 is handy for a quick long exposure still if you need to make one with the same rig. What it offers over other VND options is much better image quality and less artifacts. 

In Conclusion

Searching B&H or any other online photography store for "variable ND filter" produces a plethora of options ranging from dirt-cheap to bank-breaking. In pure cost terms, the Haida falls right in the middle of existing filters while offering an extremely high-quality image and no X pattern. If you're interested in picking one up, you can do so here.

What I Liked

• Great image quality
• Lack of X pattern
• Good range
• Magnetic design makes for easy switching

What I Felt Could Be Improved

• Brass frame
• Being able to go just a little wider (even 24mm)
• Other magnetic attachments (such as graduated filters)