Bring on the Explorer - a tougher and cheaper NiSi filter?

An image of Iceland’s Reynisdrangar sea stacks photographed with NiSi Explorer 10 Stop ND and 3 Stop Soft GND filters

After what seems like a long slumber, the photographic market seems to have suddenly woken to the fact that square filter systems used for exposure control and creative effects are suddenly a useful tool once more. When I started photography in the nineties we essentially had the choice of Cokin or Cokin if you wanted to use a system of square filters. Otherwise there was always a plethora of traditional circular filters made by everyone from Kenko to Schneider. But ultimately, if you wanted a system, it was ‘Cokin A’ or ‘Cokin P’ for the vast majority of us (this is not to say that there weren’t other options on the market, but they were often very expensive and relegated pretty much to the film industry). As the nineties turned into the noughties, brands like Lee and Singh-Ray gained more traction and filter use became more normal amongst amateur photographers. The rise of digital seemed to quell this enthusiasm for a time. At least until photographers cottoned on to the possibilities of long-exposure photography using digital cameras and very strong neutral density filters.

Still, the ability to blend images in post-production did drive down the use of filters for a brief period. Perhaps it is because photographers have realised that just because you can ‘do it in Photoshop’ doesn’t mean you should, or that it is always preferable. The result is that suddenly there are a number of new companies popping up with filter system alternatives to the original Lee, Singh-Ray and Cokin (now Hi-tech) offerings.

NiSi, a Chinese brand producing excellent optical glass is one of these entrants into the filter market. Regular readers of mine are probably well aware of the fact that I am an ambassador and rep for NiSi in South Africa, so I do speak from a somewhat biased point of view regarding NiSi filters.

My bias doesn’t change the fact that NiSi glass is not cheap. Arguably, they are well priced based on the quality and the competition. That still doesn’t make them cheap though. In order to further diversify the market, and give options to photographers, NiSi decided to bring out a slightly less expensive version of their 100mm square glass filters, which they have dubbed the ‘Explorer Range’. 


NiSi IRND 0.9 Medium Grad and 3.0 (10 Stop) ND filters on the left with their Explorer counterparts on the right.

Where’s The Difference?

When you look at an Explorer filter next to its comparable IRND filter there is little to no visible difference between the two, apart from the ‘EXPLORER’ moniker next to the NiSi name tag at the top of the filter. In every other way they are visually identical. This is the same for both the solid Neutral Density filters and the Graduated Neutral Density filters.

The difference is apparently in the glass that the Explorer filters are made from. The standard IRND filters that NiSi produces, are manufactured from optical glass, while the Explorer range are made from tempered B270 glass. In theory, optical glass should have better light transmittance and contrast values than tempered glass. However, tempered glass is more resistant to breakage than optical glass. It turns out tempered glass is also fractionally lighter, but insignificantly so for the purposes of the filters and their use (an Explorer 0.9 Medium Grad weighs 75g as opposed to the 76g that it’s IRND counterpart weighs…so an insignificant difference).

There is definitely a difference in the packaging though. The IRND filters come with a slim faux leather envelope with the opening (flap held closed by a concealed magnetic strip) on the long side of the pouch. The Explorer filters come with a slim padded canvas pouch with an opening on the short side that closes with Velcro. Frankly, if you have or are going to invest in a multi-filter pouch like the 100mm Filter Pouch Plus or something like the F-Stop Gear Filter Pouch then these small single filter pouches become redundant. If I have to choose, I prefer the canvas pouches as they seem to be more durable and are also more easily repurposed (I use them to hold and protect external hard drives and power banks when I travel).

So, is the difference in the image quality then? Both the IRND and the Explorer filters have the same nano-coating on their surfaces, the same colour neutral filtering and purportedly the same light transmittance. In fact, they are BOTH IRND filters as well (IRND standing for Infrared Neutral Density, meaning that they cut off infrared waves of light)! So the only difference is the type of glass.


I’m going to start with the claimed durability of the filters. I have been working with Explorer filters alongside my IRND kit since April (2019). In that time I have used the filters in the Drakensberg, along the Wild Coast, through numerous shoots in KZN, on a trip to Iceland and a workshop in Namibia. None of them broke. Then again, none of the IRND filters broke either. So, short of actually throwing them on a concrete floor I can’t really attest as to whether the Explorers are any tougher than the IRNDs. 

The standard IRND 3 stop Medium grad is above with the Explorer 3 Stop medium below. If you look very carefully it would appear that the Explorer image is fractionally darker in the ND section of the image (despite being taken after the IRND photo at dawn when the sky is lightening rapidly)

When the demo filters first arrived in South Africa and a set arrived at the studio, Hougaard Malan of Landscape Gear sent me a video of him dropping an Explorer grad onto a tiled floor. It shattered. He did follow it up with a text saying that it was the third attempt though. So yes, they probably are more durable than the optical glass IRND filters. I certainly haven’t molly-coddled the filters while shooting with them. I have horrified photographers on some workshops by literally tossing filters into my camera bag while changing them, so that I don’t miss the very fast changing light. My old Lee filters did not stand up to this abuse. They scratched far too easily. The NiSi filters on the other hand are quite resistant to scratching. Again, in theory, the Explorer filters should fair even better than the IRND counterparts when it comes to scratch resistance.

When I first received the Explorer filters I immediately put them under studio lights to try a comparison between using the filter and not having any filter. The images above show the results. Both the IRND and Explorer ten stop ND filters had a slight cast (pinkish magenta) which disappears if you set the white balance correctly. There is also no noticeable vignette caused by either filter. If I am picking hairs the IRND filter looks like it has slightly more micro-contrast than the Explorer, but in outside conditions it’s basically impossible to tell (as evidenced in the waterfall image that has a cropped in view of the small stream). What is noticeable though is that the Explorer has a slightly lower light transmittance, meaning that fractionally less light (I would guess 1/10th to 1/8th of a stop of light) passes through to the sensor. It’s noticeable (barely) if you shoot the filters side by side, but something you would never notice or be concerned about in actual shooting conditions.

NiSi claim that the IRND filters are going to give you better image quality. Their argument is that if you want absolute image quality, get the IRND filters. If you need durability, opt for the Explorers. Tentatively, I would agree with NiSi in this comparison. Except that I cannot reliably tell the difference between the images that I shot with the Explorer as opposed to the IRND filters. Sure, if I put the two side by side and see the actual file numbers I’ll be able to tell the difference since I was the one who used the filters in the first place, but in a blind test, it’s unlikely. It’s gotten to the point that I don’t care which filter goes in front of the lens. In real-world photography there is visually no difference between the two filters. To put it another way, there is more difference in acuity between the lenses that you use than between the two filter types. If I am on a shoot I have zero qualms putting an Explorer filter in front of my lens.


NiSi have complicated things rather than simplified the situation for photographers. NiSi’s own tests show the IRND filters to have a very slight edge in acuity (in a test bed situation). Shooting outside in the real world you will struggle to tell which filter has better contrast or acuity (in fact I would say it is near on impossible - in a blind test photographers will alternate between which filter they think is the better of the two). 

To further complicate matters the V6 kits that NiSi produce are still the best value for money when you approach their system. As an example the V6 Starter Kit Plus, comprising of 6 and 10 Stop ND filters, and 3 stop Medium and Reverse grads along with a landscape polariser, sells for R15 999. If you were to buy just the V6 holder kit and add those same Explorer filters it would actually cost more, but not include the excellent Filter Pouch Plus, blower and Magic Filter Cleaner (combined value of just over R1 000). The difference comes in the individual filter price. The IRNDs sell for between R3 299 and R3 499 (the Reverse grads are more expensive), while the Explorers all cost R2 899 each.

What the Explorer filters do offer is a slightly cheaper way to get into the system in the first place, as well as a way to supplement filters. In the first scenario, starting out, a photographer might opt just for a basic holder and two filters (a medium grad and a 10 Stop neutral density). This scenario is now a much lower entry price than the kits. One could also sample the NiSi glass by using an Explorer filter on a different brand holder (yes the Explorer filters will work on Cokin Z, Hitech, Lee and CAS filter holders - although be aware that the grads have been known to slip in the Lee holder). Similarly, the V6 Advanced Kit is quite a big jump in price from the V6 Starter Kit Plus. Adding a two stop Hard grad or a 3 stop Soft grad is now a nice to way to supplement the Starter Kit rather than getting a more expensive kit.

In terms of value for money, the Explorer filters are hard to beat. At the end of the day although you are unlikely to tell the difference visually between the two types of glass filter, you personally will know whether you have plumped for the original IRND filters - which the manufacturer claims is the better of the two - or the cheaper Explorer filters. So quite possibly the only distinction that can reliably be found between the two in the end, is whether it says ‘Explorer’ on the glass or not.

Emil von Maltitz is our go-to retailer/sales representative for NiSi filters in KZN and carries the full 75mm and 100mm NiSi product ranges at his studio in Kloof. You can reach him with the below details. 

Phone - +27 (0) 84 584 9959
Email -


The following filters are available in the Explorer Range, all priced at R2899.