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If you’re using your mirrorless camera to shoot video, you’ve probably wished for an in-built ND filter like the ones on selected camcorders and high-end cinema cameras.
Unfortunately, built-in ND filters (a.k.a. neutral density filters) are not common in mirrorless cameras.
This is where a variable ND filter (a.k.a. VND) comes in handy, allowing you to dial in the correct exposure quickly.
I’ve done much research and testing and have curated a selection I will dare to recommend.
Table of Contents
1. SLR Magic Variable ND Filter Mark II
Sizes: 52mm, 62mm, 77mm, 82mm
Stops: 1 1/3 to 6 stops (Optical Density 0.4 to 1.8)
Pros: Excellent build quality, no decrease in sharpness, pleasant warm color shift, only slight vignetting, no cross pattern at highest densities, multi-coating reduces lens flares, numbered markings on the filter rings make it easier to repeat positions, large front filter ring to avoid vignetting, side lever makes it easy to rotate the rings, internal locking ring prevents the rings from accidental rotation and change in exposure, hard stops at the minimum and maximum end of the range comes with a lens cap which fits the outer ring.
Cons: Limited range in stops compared to competitors. It’s unclear what the numbered markings mean, even though SLR Magic claims they are calibrated.
The SLR Magic Variable Neutral Density Filter MKii is my favorite variable ND filter. It offers great image quality for a very reasonable price.
The filter has a slight color shift but is pleasant and warm (no nasty greens or magenta). And it is easily corrected in post.
It doesn’t offer as wide a range of stops compared to some of the other filters on this lens. But this deliberate choice from SLR Magic makes the filter usable within the whole range.
But it does mean you’ll have to stack another ND filter on top if you’re shooting in very bright conditions with a shallow depth of field. This can cause more vignetting, especially if you’re shooting at wide angles, but it is still usable.
The build quality of this filter is excellent, and I love the lever on the side. It makes operating this filter a breeze, and you can even do it while recording without having your fingers showing up in front of the lens or risking greasing the glass.
I always use this filter with my Sigma 18-35 f/1.8, a razor-sharp lens. And the filter doesn’t seem to reduce the sharpness at all. That’s pretty incredible.
The SLR Magic Variable ND Filter Mark II is highly recommended. I only wish I had bought the 82mm version instead for reduced vignetting and because I could use it on cinema lenses with larger diameters.
I also love that this filter comes with a lens cap, which fits the larger outer ring.
2. Tiffen Variable ND Filter
Sizes: 52mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm
Stops: 2-8 stops (Optical Density 0.6 to 2.4)
Pros: Neutral color throughout the range. Minimal vignetting. Thick buttery ring for easy rotation. Nice and sharp.
Cons: Markings for reference only. Dot markings for reference only. Severe cross patterns at higher densities. No hard stops at the maximum and minimum range. It doesn’t have a lens cap that fits the outer ring.
Description: The Tiffen Variable Neutral Density Filter is popular among my fellow videographers.
The Tiffen VND has an even coloring throughout the whole range of stops.
It would have been nice if the markings were numbers because it is easy to forget which dot you set it to before. Also, the dots are for reference only and don’t correspond to a specific stop.
No hard stops at the recommended maximum and minimum range make it possible to twist the filter to unusable results accidentally.
From my experience, you’ll see bad cross patterns at higher densities, which become especially noticeable with wider-angle lenses.
Check the current price on Amazon: Tiffen VND
3. Aurora-Aperture PowerXND Mark II Variable Neutral Density Filter
Sizes: 37mm, 39mm, 40.5mm, 43mm, 46mm, 49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm, 86mm, 95mm, 105mm
Stops: Available in two versions with 1 to 7 (Optical Density 0.3 to 2.1) and 5 to 11 (Optical Density 1.5 to 3.3)
Pros: Nice color accuracy, no significant reduction in sharpness, smooth turning ring, hard stops at maximum and minimum range, a lever mount option, nano-coating helps reduce flares and reflections, thin profile.
Cons: Equally sized front thread (please read the description); symbols on the filter are for reference only.
Description: Aurora-Aperture made a splash in the industry when they launched their first iteration of this filter through a Kickstarter campaign.
In this second iteration, they’ve improved upon most of the critique points from their first filter and have made a great filter, which is reasonably priced.
The major and most apparent difference is that they’ve decided to split the first filter’s range of stops (from 1 to 11) into two separate filters.
This is a wise choice because it makes the cross-patterning much less apparent at higher densities. And there’s an overlap in stops between 5-7, so you can choose the filter that gives you the best results.
It does, however, mean that you’ll have to purchase two filters instead of one if you want the full range. But you’d had to do it anyway because the higher densities of the first filter were unusable.
The filter gives you a very natural color rendering and is on par when it comes to sharpness with the SLR Magic and the B&W already mentioned.
The Aurora-Aperture VND also has hard stops at the maximum and minimum settings and symbols, which makes it easy to dial in a specific setting. The symbols are for reference only, though.
I also really like the fact that you can remove the lever. That way, you won’t have to worry about it breaking off if you transport your camera and lens with the attached filter.
Aurora-Aperture points out that the filters come with equally sized front threads. They claim this as a special feature because most other brands have a larger front filter, which means you can’t use the original lens cap of your lens.
I’m not a big fan of this design choice because it makes the filter prone to vignetting when stacking other filters on top and when you’re shooting wider angles.
I prefer to have a second lens cap, which fits the outer ring thread of my filter.
These are great filters at a very affordable price.
4. Genustech Eclipse Variable Neutral Density Filter
Sizes: 77mm, 82mm
Stops: 2 to 8 stops (Optical Density 0.6 to 2.4)
Pros: Very sharp, smooth ring, great build quality, thin, large front filter thread.
Cons: Greenish color shift, no hard stops, no lever option, doesn’t come with a lens cap, which fits the outer ring.
Description: Despite its name, the Genustech “Eclipse” is not meant for photographing or recording an eclipse or the sun. For that, you’ll need a much higher-density filter.
This filter renders a sharp image. I have not seen any difference in sharpness with or without this filter.
The filter has a great build quality, and the ring is smooth to turn.
I wish they’d added a lever option and hard stops at the minimum and maximum ranges. A cross will appear at wider angles or when you go above the maximum recommended stop.
The larger front filter thread helps reduce vignetting.
If you’re after sharpness and don’t mind correcting for the green tint in post this is the filter for you.
5. B+W XS-Pro Digital ND Vario MRC-Nano Filter
Sizes: 40.5mm, 46mm, 49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm, 95mm.
Stops: 1 to 5 stops (Optical Density 0.3 to 1.5).
Pros: Excellent build quality, minimal vignetting, buttery smooth ring, no cross patterns to speak of, no degradation in sharpness, multi-coating to reduce glare and flares, hard stops at maximum and minimum range.
Cons: The stops are for reference only. The price doesn’t include a filter cap yellow color cast.
Description: The B+W XS-Pro Variable ND filter is a high-end product and the most expensive filter on this list.
It has an excellent build quality and no vignetting from what I’ve seen. Vignetting only starts to show wider angles when you’ve added another filter on top.
The ring is buttery smooth to work with, but as a lever fan, I wish they’d added this option.
I’ve also not seen cross-patterning, probably due to the limited range. Like the SLR Magic filter mentioned on this lens, B+W has chosen to limit the range of stops for the best optical performance throughout the whole range.
It has a slight yellow tint, which you must correct in post or by using white balance while you record.
And I feel that at this price point, B+W should have included a filter hood, a.k.a. lens cap, which fits the larger outer ring.
All-in-all, this is a higher-end product that offers great image quality and build quality for the price.
Check current prices on Amazon: 46mm, 77mm, and 95mm.
6. PolarPro VariableND Peter McKinnon Edition
Sizes: 67mm, 77mm, 82mm
Stops: Two types available: 2 to 5 stops (Optical Density 0.6 to 1.5), and 6-9 stops (Optical Density Range 1.8 to 2.7).
Pros: Excellent build quality, no vignetting down to 16mm (Full frame), smooth ring, hard stops at maximum and minimum range, no degradation of sharpness, no cross patterning, filter cap included, both hard and soft bag included.
Cons: The stops are for reference only, no lever option, pricy.
Description: I’ve used a lot of PolarPro filters – ND, polarizers, and more. I own some for my DJI Mavic Pro and a couple of sets for my Laowa 7.5mm lens. And the filters have all been of good quality.
So, I was excited to learn about this new set of variable NDs from PolarPro, endorsed by famous YouTuber and filmmaker Peter McKinnon.
The filters are available in two versions. A 2-5 stop version (ND4 to ND32 / Optical Density 0.6 to 1.5) and a 6-9 stop version (ND64 to ND512 / Optical Density 1.8 to 2.7).
PolarPro has made a wise choice by limiting the density range and adding hard stops to each filter version. It gives you the best optical quality without vignetting (unless at wide angles) and zero cross-patterning.
I’m always wary when a brand tries to push a product with the help of an internet celebrity. But from what I’ve seen so far, PolarPro has created a high-quality product, which is highly recommended.
So, for once, the influencer and brand symbiosis has paid off for the consumer’s benefit (a.k.a. you and me).
Unless you only own lenses with a diameter of less than 67mm, I would recommend you buy the 77mm or the 82mm version and then buy step-up rings. That way, you can use these great filters on many lenses.
The 2-5 stop filter is cheaper than the 6-9 one.
7. Moment Variable ND Filters
Sizes: 67mm, 77mm, and 82mm
Stops: Two types available: 2 to 5 stops (Optical Density 0.6 to 1.5), and 6-9 stops (Optical Density Range 1.8 to 2.7).
Pros: Excellent build quality, hard stops at maximum and minimum range, no degradation of sharpness, no noticeable color shifts through the ranges, no cross patterning, nice flaring, and lifetime warranty.
Cons: The laser engraved stops are not on top of the lens, no lever option, no filter cap included, and there is slight vignetting on the 6-9 stops filter.
Description: Moment has made a set of high-quality variable ND filters that complement each other well.
Moment did the right thing and made two filters with hard stops – each within a limited range of stops – instead of making a single filter to cover the whole range from ND4-ND512.
This has resulted in filters with no cross-patterning, no color shift through the ranges, and minimum vignetting (only on the 6-9 stops filter at maximum densities).
I couldn’t get the laser engraved stops to be where they were supposed to be with my lens and step-up ring.
I would also have liked a (detachable) lever and a center pinch lens cap to be included with each filter.
But all in all, these are excellent filters.
Buyer’s Guide to ND filters. What is an ND filter, and why should you use one?
ND is an abbreviation of “Neutral Density”. ND filters filter out a certain amount of light to reduce the exposure. In that way, an ND filter is like sunglasses for your camera lens and sensor.
Because of this, ND filters are an incredibly useful tool for video – especially if you’re filming in bright sunlight – because they make it possible to capture footage even at fast apertures and shallow depth-of-field without overexposing the image.
If you’re a photographer, ND-filters is an incredibly creative tool to capture long-exposure photographs. So, if you’re looking to capture that silky look of waterfalls, the glass-like look of lakes, or blurry streaks of clouds, an ND filter is the way to go.
If you’re a videographer, using ND filters is usually slightly different.
Of course, ND filters for video still lower the exposure. However, the creative use of ND filters for long exposure times is usually more suited for landscape or cityscape photography.
In video, we often work with a fixed shutter angle of 180 degrees or a shutter speed of approximately double the frame rate.
In other words, we are left to play with the ISO and aperture.
If you want to shoot at a wide aperture for a nice bokeh and shallow depth-of-field outside in bright daylight, there’s a good chance your image will be overexposed. You might try to set your camera to the lowest possible ISO, but most often, that still won’t be enough.
This is where you bring out your ND filter.
What is a variable ND filter, and why should you use one?
Regular (non-variable) Neutral Density filters stop a specific amount of light from passing through. One filter might filter out two stops of light and another ten stops. I’ll get into all the technical stuff about stops of light and how they’re written on the filter in a minute.
The point here is to understand that if you have a regular ND filter mounted on the lens, which filters out two stops of light, and you need a filter of four stops, then you need to exchange the filters, which takes time.
Variable ND filters allow you to continuously adjust the filter’s density by twisting a ring on the filter. This changes the density of the filter – and thus the amount which is let through to the lens.
I find VNDs that don’t have hard stops at the minimum and maximum range of stops the easiest to work with, as they prevent me from setting the filter to extremes and avoid severe cross-patterning. More on that later.
Variable ND filters override the hassle of exchanging filters in run-and-gun situations
When it comes to mounting a neutral density filter, there are three choices:
- screw-in filter (you screw in the filter using filter threads at the end of your lens)
- matte box (or slot-in in photography)
- Clip-in (sits just in front of your mirror in DSLR cameras in the camera body itself). This is somewhat similar to the placement of in-built ND filters on cinema cameras, though these can be operated and exchanged by a switch on the camera.
Matte boxes are handy for quickly exchanging filters – or when you want to stack several filters (like an IR filter, a polarizer, and an ND).
If you want a quick overview of different types of filters for video, I recommend you read our guide The Five Types of Lens Filters You Need For A Cinematic Look.
ND filters are also available as graduated filters, which you can read more about by following the above link. But I’ve yet to see a graduated variable ND filter so I won’t get into those filters in this article.
Even though matte boxes are great in controlled environments like a studio or a film set, they are also big and clunky. If you’re going handheld, e.g., for a documentary where you don’t want to draw too much attention to yourself, then a matte box is not the best choice as it screams film.
Clip-in filters aren’t great either because they take a long time to remove and attach as you need to remove the lens first and then reach into the camera body to pull the filter out and replace it with another.
This leaves you with screw-in ND filters as your best option for run-and-gun scenarios.
I would recommend a variable ND filter for such scenarios, and here’s why.
Even though I own several regular threaded screw-in ND filters, I’m not too fond that switching between them takes quite some time when I shoot video.
Regular filters can tend to get stuck in the filter thread and can be hard to remove and exchange, which means I might miss my chance to get the footage I want.
That’s why I prefer to work with VNDs for most run-and-gun scenarios.
How To Attach A Screw-In Variable ND Filter To Your Lens
So, how do you attach an ND filter to your lens?
Well, it sounds simple, right? You buy one and screw it into your lens.
In reality, it is just as simple as that when the filter matches the diameter of your lens.
But what if it doesn’t? In that case, you need something called step-up rings.
For example, if your lens has a filter thread with a diameter of 72mm, and you get a 77mm filter (a common size), then you need step-up rings to take the diameter of the lens from 72mm to 77mm.
Brass rings, such as these from Luzid, are typically a better choice than metal rings, as brass doesn’t get stuck as quickly in the metal threads of your lens or filter.
Also, it is always a good idea to get larger filters. For example, if your lens is 72mm and you can choose between a 77mm and an 82mm ND filter, it can be a good idea to get the 82mm.
Not only can this reduce the risk of vignetting (especially with wide-angle lenses), but you will also be able to use the filter on bigger lenses – for example, cinema lenses – in the future.
Does An ND filter Affect The Image Quality?
The quick answer to this question is “no, but…”.
As the name implies, neutral density filters should be neutral in color and only reduce the exposure.
Unfortunately, that is not always the case. Cheap filters have nasty color shifts, shadows, or vignetting.
That is why it isn’t wise to cheap out on your ND filter. Don’t get lured in by those cheap filters you find online. If that is all you can afford, it’s better not to use a filter and wait until you’ve saved up the money for a good filter.
This is an even more pronounced problem in variable ND filters. The reason for this is how a variable neutral density filter is constructed.
A variable ND filter consists of two polarizer filters (a.k.a. CPLs) combined.
A quick note on polarizers
As you might know, polarizers only allow light to pass through from a certain angle and work best at a 90-degree angle from the sun.
Polarizers are great for reducing glare from windows or the reflective surface of the water. They are also great if you want to saturate the colors fx of the sky or a field of flowers.
There are two types of polarizers: linear and circular.
Circular polarizers are linear polarizers with a quarter wave plate on the back, which turns linearly polarized light into circularly polarized light.
In theory, and some rare circumstances, linear polarizers can confuse the autofocus system of digital SLR cameras with mirrors, which is why circular polarizers are recommended. For mirrorless cameras, I can’t see that it should make a difference. But please correct me if I’m wrong.
It is beyond the scope of this article to dive into more detail about polarizers. But now you’ve hopefully got an idea of the constructs of a variable neutral density filter.
So Does A Variable ND Filter Affect The Image Quality?
The short answer is “yes”. Variable ND filters will always affect the image quality.
On low-quality variable ND filters, artifacts such as vignetting, color shifts, or a cross-pattern in the middle of the image when the filter is at maximum density are more pronounced.
The cross-pattern can even be found on high-quality VNDs, so it is always wise not to fully close the filter if possible.
Variable ND filters may also suffer from infrared pollution. But this can easily be negated by stacking an IR filter before the VND.
The point here is that a variable ND filter is only as good as the quality of the linear and circular polarizers combined. But even the most expensive filter can still suffer from a bit of vignetting, color shift, softness, or cross patterns – or all combined.
The question becomes how much the filter suffers from it and if, e.g., the change in color or softness is pleasing or not.
Whatever type of filter you choose, investing a bit of extra money in a good ND filter is always wise.
How does an ND filter work?
ND filters stop a certain amount of light from passing through, which can be written differently depending on the manufacturer.
Before I get into the semantics, let’s talk about the general way to know how much light the ND filter stops – which is called “stops.”
The amount of light passing through photographic lenses is described in f-stops.
Here, you can see a typical range of f-stops for a lens:
A stop is either a halving or a doubling of the light that is let through to the sensor.
For example, a lens with an f-stop of f/1.4 will allow twice the amount of light through compared to a lens with an f-stop of f/2.0. An aperture of f/2.8 will allow half the amount of light compared to a lens with an aperture of f/2.0, etc.
If you’re new to apertures and want to learn more about exposure, apertures, f-stops, and t-stops, I would recommend you start by reading my guide, How to Choose the Right Camera Settings for Video Production, which will guide you through all the basics.
Equally, an ND filter of three stops will allow only half the light through compared to an ND filter of two stops.
An ND filter of three stops will allow double the amount compared to an ND filter of four.
An ND filter of two stops will allow four times more light through than an ND filter of four. An ND filter of one stop will allow eight times more light than an ND filter of four stops.
If you want to compare the amount of light that is let through a filter (fx two stops) to a filter with another number of stops (fx 7 stops), it is important that you add each halving of the light sequentially.
|ND filter in stops||Amount of light let through compared to no filter|
|0 (no filter)||All light|
So, an ND filter of 10 stops will only allow 1/1024 of the light through compared to using no ND filter.
An ND filter of 10 stops will only allow 1/512 of the light through compared to an ND filter of 1 stop.
An ND filter of 10 stops will allow 1/256 light through compared to an ND filter of 2 stops.
You can find ND filters that filter above 30 stops of light. You can also find regular ND filters that are measured to a fraction of a stop (like 13 1/3).
Variable ND filters without hard stops let you continuously adjust the light reduction between full stops.
With me so far? Great! Now, it gets a bit confusing.
What do the numbers on ND filters mean, and how do you read them
Okay, so let’s say you change your aperture from f/2.8 to f/1.4 but want to maintain the same exposure.
That’s two f-stops, which equals four times as much light passing through the lens to the sensor.
Okay, now all you have to do is grab the ND-filter in your bag, which says “ND-filter reduction of 2 stops of light”. Easy right?
Well, if only it were so easy. Manufacturers have decided it would be awesome to use the terms ND filter factor or optical density instead, which each corresponds to a specific number of stops. You know, to separate the wheat from the chaff or something.
So here’s a chart for you, which compares the different numbers to each other.
|Reduction of Light in Stops||Optical Density||Filter Factor||Amount of light let through compared to no filter|
|0 (no filter)||0||0||0|
|6 2/3||ND 2||ND100||1/100|
Optical Density and Filter Factor numbers are sometimes written with an “ND” before the number itself and sometimes not. For example, it might say ND2 – or it might just say 2.
So before you buy any ND filter, you need to read the fine print from the manufacturer carefully. Because as you can see from the table above if the ND filter only says ND2, it could mean both 6 2/3 stops of light (optical density) or one stop of light (filter factor). That’s quite a significant difference.
And to make matters a bit more confusing, an ND filter of 10 stops is also known as an ND1000.
I’m not exactly sure why that is the case, so my best guess is that it has to do with the fact that ten stops of light correspond to a filter factor of 1024 (or 1/1024th of the unfiltered light). If you know the answer, please share in the comment section below.
Something that seems to support this case is that a six-stop filter is also known as an ND64 because it only lets through 1/64th of the unfiltered light.
For the sake of sanity, for the rest of this article, let’s talk about ND filter light reduction in terms of stops.
And let’s hope that all the manufacturers will one day sit down in a room together and agree. I’m sure the day is just around the corner. Or maybe not.
How many ND filter stops do you need? And within which range?
With ND filter stops from below one to over twenty, you may have been wondering, “How many stops of ND filter do I need for video?”
The thing with VNDs is that even though some filters might advertise 9 or 10 stops of light reduction, they’re rarely usable in the last two to three stops because of heavy shifts in color or cross patterning.
So, for instance, if you’ve bought a VND with nine stops, you might only get good usable results up to six or seven stops.
Some manufacturers – like SLR Magic – have decided instead not to make VNDs with so many dense stops because of these problems. So, their filters have a shorter range of stops.
Here’s a quick test to see the number of stops available on the SLR Magic Variable ND Mark II in action:
So expect about the same usable range in stops for all of these filters – about six or seven.
In terms of range, I would say a good rule of thumb is from around 0.5-1 to 6 or 7 is a good place to start.
If you need denser filters, you can stack a regular ND on top of the VND. That way, you won’t get the weird color shifts at higher densities.
So, for example, if you own a VND that goes from 1 to 10, you will get a better result by dialing the VND up to stop six, maybe, and then adding a regular ND with an extra four stops.
How to pick the best ND filter for time-lapse videos with longer shutter speeds
I wouldn’t recommend a variable ND if you’re shooting time-lapse videos with long shutter speeds. Instead, I would probably go for regular ND1000 first (depending on the course conditions).
This is because variable ND filters, which go all the way to 10 stops, are not common. This is probably because, at those densities, color shifts are prone to occur due to how variable ND filters are constructed.
Also, timelapse videos are rarely run-and-gun scenarios. They usually require quite a bit of planning and setup. So, you’ll have plenty of time to set your exposure and choose the right ND filter for the job.
So that’s it. Did I miss any? Do you have a good or bad experience with these filters? Please let me know in the comments.