With so many different types of ND filters out there, knowing which filters to buy isn’t easy. In this buying guide, we explain the differences between each ND filter on the market, as well as the photography situations they’re best for.
Words and Photography by Urth HQ
A Neutral Density filter is a lens filter that blocks light from entering your camera. Why would you want to do that? It’s useful if you want to soften bright light, slow down your shutter speed for motion blur effects, widen your aperture for depth of field effects in bright light, or create more cinematic effects when filming. We’ll go into more detail about these effects later in the guide.
Are you new to ND filters? If so, head to our ND filter beginners guide to understand the basics.
What’s the difference between a fixed ND and a variable ND?
There are two types of ND filters. Fixed ND filters and variable ND filters.
Fixed ND filters block a fixed f-stop of light from entering your camera. Variable ND filters provide more flexibility. Variable ND filters will have a range of f-stops you can block. By rotating the outer element of a Variable ND, you can adjust the amount of light entering your camera.
If you’re starting out with ND filters and wondering what ND filter is most useful, we recommend a Variable ND so you have more flexibility while you’re learning how to shoot with an ND filter.
What do the ND filter numbers mean?
The higher the number in an ND filter, the less light is passed through the lens.
For example, an ND2 filter lets in 50% less light than no filter, and an ND4 lets through half as much light again, or 25% light transmission. Every time the ND factor number doubles, there’s a 50% reduction in light transmission, which represents one extra f-stop of light being blocked from entering your lens.
See the ND filter chart below to understand more on the ND filter factor numbers, their f-stops of light reduction and the amount of light it transmits to your lens.
ND filter chart
Use the chart below to understand the light reduction and transmission that results from each type of ND filter.
|ND Filter||Light Reduction||Light Transmission||Best Light Conditions|
|ND2||1 f-stop||50%||Low light|
|ND4||2 f-stop||25%||Low light|
|ND8||3 f-stop||12.5%||Low light|
|ND16||4 f-stop||6.25%||Low light|
|ND32||5 f-stop||3.12%||Bright light|
|ND64||6 f-stop||1.56%||Bright light|
|ND128||7 f-stop||0.78%||Bright light|
|ND256||8 f-stop||0.39%||Harsh light|
|ND512||9 f-stop||0.19%||Harsh light|
|ND1000||10 f-stop||0.10%||Harsh light|
|ND10000||13 f-stop||0.01%||Harsh light|
What strength ND filter should I buy?
Below we’ll explain the primary purpose of each strength of ND filters, and the lighting situations they’re best suited for – but keep in mind that they can still be used in other conditions. For example, while an ND8 is designed for use in low light, you can still use it in harsh light if you only want to cut out 3 f-stops of light. It depends on what results you’re after. More on that below.
Explore low light – ND2, ND4, ND8, ND16
In low light, you’ll need to have your aperture quite wide and/or your shutter speed slow to get enough light in. These fixed ND filters are best for low light because there’s not a lot of light in your environment to block so you only want a low ND filter effect.
These ND filters can be used to create stronger motion blur effects in low light. By blocking 2, 3, and 4 f-stops of light, these filters allow you to slow your shutter speed down, without overexposing your image, to create beautiful motion blur.
Alternatively, you can adjust for the decreased light transmission by opening your aperture right up. This will let you achieve a shallower depth of field (DOF) effect. You can also adjust both your shutter speed and aperture for a combined effect. E.g. Your aperture is at f2.8 and your shutter is at 1/30th but you want to get stronger motion blur without losing your shallow DOF. You pop on an ND4 and you can slow your shutter down 2 stops to 1/8th for stronger blur.
GREAT FOR PORTRAITS
Low light ND filters are popular with portrait photographers who want to achieve a more dramatic shallow DOF.
GREAT FOR FILMING
The 180-degree rule says for natural movement, your shutter speed should be double your frame rate. Usually, that is 1/50th at 25 frames per second. You can use these low light ND filters to avoid overexposing your scene when stepping into brighter light when filming. You can adjust your ISO to account for brighter light when filming but you’ll find ND filters allow for a lot more control and a better outcome.
STILL FINE IN BRIGHT LIGHT
While not designed for it, these ND filters can still be used for subtle creative effects in bright light. It would be more cinematographers who use them in bright light, but photographers can still achieve stronger motion blur and DOF effects in bright light with these filters.
See how Urth ambassador Denisse Ariana Pérez used an ND8 filter in bright light to condense the light and deepen colours.
ND FILTERS 2-16 ARE GREAT FOR
To sum up, ND2 ND4, ND8 and ND16 filters are great for:
1. Landscape photography in low light
2. Outdoor photography in low light
3. Travel photography in low light
4. Indoor photography
5. Portrait photography
6. Cinematography in bright light
Soften bright light – ND32, ND64, ND128
In bright light, to correctly expose your photograph, you’ll need to have your aperture quite closed-off (probably f8 and above) and/or your shutter speed fast. An ND32, ND64 and ND128 are all perfect for bright light because they give you 5, 6, and 7 f-stops of light reduction giving you a lot of freedom to open your aperture and slow your shutter in bright light.
These filters allow you to achieve stronger motion blur effects in bright light. Even if you lower your ISO and close-off your aperture, slowing your shutter speed for motion blur can still overexpose your photograph. These bright light ND filters allow you to slow your shutter speed down without overexposing your image, to create beautiful motion blur.
Say it’s a sunny day and you want to shoot some portraits with a shallow DOF with that beautiful blurred background (bokeh) effect. To get that, you need to have a wide aperture, which means you need to compensate with a super fast shutter speed to avoid an overexposed photo. But your camera may only go up to 1/2000th of a second. An ND64 allows you to keep your aperture wide open, say f1.4, without overexposing your shot. So you can shoot at: ISO 100, f1.4, and 1/1000th sec with an ND64 and get that beautiful bokeh effect.
GREAT FOR LANDSCAPES
Bright light ND filters are popular with landscape, outdoor and travel photographers who regularly encounter bright light. Whether it’s softening bright light, creating a shallower DOF or achieving some motion blur under blue skies, bright light ND filters give landscape photographers a huge amount of exposure latitude, which means more ways to capture landscapes.
See how photographer Caitlin Fullam used a Variable ND filter set at ND128 to create motion blur with clouds in her landscape shots.
Overcome the restrictions of the 180-degree rule and enjoy more flexibility with exposure while filming. Use these bright light ND filters for better control and a more cinematic outcome.
ND FILTERS 32 – 128 ARE GREAT FOR
To sum up, ND32, ND64 and ND128 filters are great for:
1. All types of photography in bright light
2. Longer motion blur in bright light
3. Shallow depth of field in bright light
4. More cinematic video effects in bright light
Rethink harsh light – ND256, ND512, ND1000, ND10000
When you want to shoot long exposures in bright light, or soften harsh light and create some flexibility with your exposure settings, you need strong ND filters. The ND256, ND512 and ND1000 are made for long exposure photography in bright light and can be used to soften harsh light because they give you 8, 9, and 10 f-stops of light reduction.
With these strong ND filters, you can shoot super long motion blur effects in harsh light. These filters allow you to slow your shutter speed down 30 seconds and longer. If you’re shooting a landscape in the desert on a beautiful sunny day and want to blur with the clouds, you’ll need to block a lot of light to slow your shutter speed down to say 15 seconds.
If you’re shooting motion blurs where correct exposure is ISO100 with an aperture of f22 and a shutter speed of 1/60, you can use our ND1000 to slow your shutter to 15 seconds for a much more intense effect. The difference in motion blur between 1/60th and 15 seconds is dramatic and impossible to achieve in harsh light without one of these ND filters.
DEPTH OF FIELD EFFECTS IN HARSH LIGHT
Think sunny days on snow, ice or sand. An 8, 9 and 10 f-stop light reduction is huge – the ND1000 blocks 99.99% of light entering your camera so that’s why it’s mainly used for long exposure photography. But you can still use these ND filters to open up your aperture for shallow DOF effects in harsh light.
See how Urth ambassador Chiara Zonca used an ND1000 for shallow depth of field in the desert.
ND FILTERS 256 – 1000 ARE GREAT FOR
To sum up, ND256, ND512, ND1000 and ND10000 filters are great for:
1. Long exposures in harsh light
2. Super long exposures in harsh light
3. Shallower depth of field in harsh light
Experiment with ND filters
ND filters are an amazing tool to have in your photography kit. Use the chart in this guide to better understand what effect the different types of ND filter will create.
If you’re unsure where to start, a Variable ND is the easiest way to learn as you play around with the different f-stops. It offers multiple options in one filter.
Perhaps the most incredible benefit of ND filters is that they let you shoot so much more. Armed with an ND filter you’ll no longer be restricted to shooting during the golden hours around sunrise and sunset.
Discover Urth’s collection of ND filters and get creative in different types of light.