If you’re reading this, congratulations – you’re in the market for one of the most essential filmmaking accessories (just behind stabilization and a good mic).

If you already know the ins and outs of the ND filter, scroll down to the ‘Best Variable ND Filter for Video’ section. If not, read on for some education!

An ND or ‘neutral density’ filter is a dark piece of glass that reduces the amount of light entering your lens by a given amount of ‘stops’, or exposure values (think the reduction in light that happens when you halve your ISO or shutter speed – that’s a ‘stop’). They tend to scale in price both as the light reduction increases in stops and the filter thread size increases.

A variable ND filter is serves the same purpose as a regular ND filter, but instead of limiting you to any given number of stops, it has a rotating element . If you’re shooting outside, at an event, or anywhere with variable lighting conditions, the variable ND filter is an absolute life-saver.

So why is this piece of gear so important? In most cases, long exposure photography and almost any kind of videography can’t be pulled off without limiting the light you put into the lens (counter intuitive, I know). When you’re shooting video, your shutter speed has to precisely double the frame rate – 1/50 for 24fps, 1/60 for 30 fps, 1/120 for 60fps, etc. That means that you can’t use the shutter speed to control the amount of light in your scene – only the aperture and ISO. But then again, what if you want a shallow depth of field? Add in the native ISOs of some cameras being 400 or even 800, and you begin to see how quickly an image can become overexposed.

The final consideration when shopping for an ND filter is the size of your lenses. Unless you have money to burn, your best bet is to buy the absolute largest ND filter you’ll ever need along with a set of step up rings. The step up rings allow you to use your one ND filter on your biggest lens all the way to your smallest without much hassle at all.

Best Variable ND Filter for Video

B+W XS-Pro Digital ND Vario MRC Nano Filter

The best ND filter currently on the market is the B+W XS-Pro, a 77mm variable ND filter with 5 stops of light reduction. Yes, that’s a lot of money for an average amount of light stopping power. But if build and image quality is the absolute priority – meaning perfect clarity and even light reduction through every stop of the filter, this is your best bet.

Hoya 77mm Variable Neutral Density (ND) Filter

I’ve had the Hoya 77m variable ND filter (9 stops of light reduction - wow!) for about two years now, and I can’t even begin to express exactly how much I love this thing. Paired with an IR filter, variable polarizing filter, and my trusty step-up rings, and I have a perfect, professional lens setup for any focal length and any environment. Yeah, I love this thing.

But keep this in mind: if you exceed the markings on the filter, you may get halos, blobs, of vignetting. Sounds easy enough, but in a frantic situation it might slip your mind. That’s the real difference between the B+W and the Hoya, so make your choice accordingly.

Best Affordable Variable ND Filter for Video

Tiffen 77mm Variable Neutral Density Filter

The Tiffen is still not necessarily cheap – we’ll get to that next – but if you’re looking for a neutral density filter for video, you’re going to want to spring for a variable version – and this is the top quality available for under $100 dollars. The quality control on Tiffen tends to be solid, and this filter offers 7 stops of light reduction – no joke.

ZoMei 72mm Ultra Slim

This ultra-budget variable ND filter isn’t necessarily recommended for professional work – color casts and imperfect light reduction across the filter are common complaints – but for a vlogger, Youtube, Instagrammer, or somebody trying to build a starter video kit, look no further!

With 7 stops of light reduction, the ZoMei offers serious bang for your buck – just be aware that the largest filter thread size currently available is 72mm.