Best Variable ND Filter for Irix 15mm f/2.4
Finding a variable ND filter for the Irix 15mm f/2.4 is a notorious challenge because of its massive 95mm filter thread and ultra-wide field of view. Most filters at this size either introduce a nasty “X-pattern” or degrade that surgical Irix sharpness. After testing several options on my own 15mm setup, I’ve found that the PolarPro PMVND Signature Edition II is the clear winner for maintaining professional image quality without the typical wide-angle headaches.
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Best Variable ND Filter for Irix 15mm f/2.4: Detailed Reviews
PolarPro PMVND Signature Edition II View on Amazon View on B&H
When you’re shooting with a lens as wide and sharp as the Irix 15mm, you cannot afford subpar glass. The PolarPro PMVND Signature Edition II (2-5 stop version) is arguably the finest 95mm variable ND on the market. It features fused quartz glass that maintains the Irix’s legendary resolving power even at the edges of the frame. The haptic feedback mechanism is a game-changer; you can feel the clicks as you adjust, ensuring you don’t over-rotate and cause the dreaded cross-polarization “X” that plagues wide-angle lenses. I find the color neutrality here to be exceptional—there’s almost zero shifting toward green or magenta. While the price tag is steep, the build quality and the included Defender cover provide peace of mind for rugged outdoor use. The only downside is that you won’t be able to use the original Irix lens hood, but that’s a trade-off with almost any 95mm filter.
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Freewell Variable ND (Standard Day) View on Amazon View on B&H
Freewell has built a reputation for delivering high-end optics at about half the price of premium brands. Their 95mm Variable ND for “Standard Day” (2-5 stops) is the sweet spot for Irix users who want quality without spending $300. The hard stops are a crucial inclusion; they physically prevent the filter from rotating past its usable range, which is vital on a 15mm focal length where the X-pattern usually appears earliest. In my testing, I noticed very slight vignetting when using the filter at its maximum 5-stop setting on the Irix, but it’s easily correctable in post-production. The glass is multicoated to be oil-resistant and dust-resistant, making it a great companion for landscape photographers. You’ll get sharp results, and while the color shift is slightly more noticeable than the PolarPro, it remains well within professional standards. It’s a workhorse filter that punches way above its weight class.
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K&F Concept Nano-X Variable ND View on Amazon View on B&H
Let’s be honest: 95mm glass is inherently expensive. K&F Concept manages to offer a viable “budget” option that doesn’t completely ruin your image quality. The Nano-X series uses Japanese AGC glass and features 28 layers of multi-coating. On the Irix 15mm, you’ll want to stay within the middle of the 1 to 5 stop range to avoid corner darkening. The slim frame is particularly helpful here, as it reduces the chances of mechanical vignetting at f/2.4. You might notice a slight warmth (yellowish tint) added to your images, which actually works quite well for sunset landscapes but might require a white balance tweak for skin tones. While it lacks the refined haptics of the PolarPro or the hard stops of the Freewell, it’s a solid, reliable piece of kit for someone who only needs an ND filter occasionally. For the price, it’s remarkably well-built and provides a way into long-exposure photography without a massive investment.
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NiSi True Color VND View on Amazon View on B&H
The NiSi True Color VND is specifically designed to solve the one problem that plagues almost every variable ND: color shift. Traditional VNDs use two polarizing layers that often create a yellow-green cast; NiSi’s “True Color” film mostly eliminates this. For Irix 15mm owners who specialize in architectural or landscape photography where color accuracy is paramount, this is the gold standard. It offers a 1 to 5 stop range with a removable control lever, which is incredibly handy when you’re wearing gloves in the field. The glass is exceptionally clear, and the nano-coating does a great job of shedding water droplets—perfect for shooting near waterfalls or the ocean. You’ll find that it maintains the contrast of the Irix lens beautifully. It’s nearly as expensive as the PolarPro, but for those who prioritize color fidelity over haptic clicks, the NiSi is the superior choice.
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Urth Variable ND2-400 (Plus+) View on Amazon View on B&H
Urth (formerly Gobe) offers a fantastic “Plus+” range that utilizes premium German Schott glass. This 95mm variable ND provides a broader range (1 to 8.6 stops) than the 2-5 stop filters mentioned above. While this gives you more flexibility for extremely long exposures, you have to be more careful with the Irix 15mm. Because it’s an ultra-wide lens, pushing this filter to the 8-stop mark will almost certainly result in an X-pattern. However, if you use it within the 2-6 stop range, the results are wonderfully crisp. I love the minimalist design and the fact that Urth plants five trees for every filter purchased. It’s a great middle-ground option for photographers who want better glass than K&F but don’t want to jump to the NiSi/PolarPro price bracket. The build quality is excellent, with a magnalium rim that feels very durable in the hand.
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Buying Guide: How to Choose a Variable ND for Irix 15mm
Comparison Table
| Product | Best For | Rating | Price |
|---|---|---|---|
| PolarPro Signature II | Professional Video | ★★★★★ | Check |
| Freewell VND | Best Value | ★★★★☆ | Check |
| K&F Nano-X | Budget Shooters | ★★★★☆ | Check |
| NiSi True Color | Landscape Purists | ★★★★★ | Check |
| Urth Plus+ | Eco-Friendly | ★★★★☆ | Check |
Frequently Asked Questions
Can I use my Irix lens hood with these filters?
Generally, no. The Irix 15mm f/2.4 has a proprietary hood that mounts to the outside of the barrel. Once you screw in a massive 95mm variable ND filter, the outer diameter of the filter usually exceeds the space allowed by the hood’s mounting mechanism. You’ll need to rely on the filter itself to handle flare, or use a matte box if you are shooting video.
Why does my 95mm VND show a dark ‘X’ in the middle?
This is called cross-polarization. It happens when the two polarizing layers inside the VND are turned too far relative to each other. It is much more common on ultra-wide lenses like the 15mm because the light enters the lens at extreme angles. To avoid this, stick to 2-5 stop filters and choose models with hard stops that prevent over-rotation.
Is 95mm the correct size for all Irix 15mm versions?
Yes, both the Blackstone and Firefly versions of the Irix 15mm f/2.4 share the same 95mm front filter thread. This is one of the largest filter threads for a consumer lens, which is why the filters are more expensive than standard 77mm or 82mm options. Always double-check the box to ensure you haven’t accidentally ordered an 82mm version.
Should I get a 2-5 stop or a 6-9 stop filter?
For the Irix 15mm, I almost always recommend the 2-5 stop range. Ultra-wide lenses struggle with the physics of variable NDs as the density increases. A 6-9 stop filter is much more likely to show uneven darkness or the X-pattern across a 15mm frame. If you need 10 stops of light reduction for long daytime exposures, a fixed ND is usually a better choice.
Do these filters affect the focus scale of the Irix?
The Irix 15mm is known for its precise focus scale and “click” at infinity. High-quality filters like the PolarPro or NiSi use thin, optically flat glass that should not noticeably shift your focus point. However, extremely thick, cheap filters can occasionally cause a tiny shift in the infinity focus point. It’s always best to verify focus using live-view magnification after mounting the filter.
Final Verdict
If you are a professional videographer using the Irix 15mm for high-end production, the PolarPro Signature Edition II is worth every penny for its lack of artifacts. For landscape photographers who want color accuracy, the NiSi True Color is the way to go. However, if you’re just starting out or want a solid filter for occasional use, the Freewell offers nearly pro-level results at a much more digestible price point for 95mm glass.