Creating Art in Landscapes with Neutral Density Filters
Neutral Density Filters are an essential part of your landscape photography kit. They allow you to create artistic results that you just can't mimic in post-processing. I'd never dream of going out on a shoot without them!
The same scene shot without filters vs with filters (polariser and 6-stop ND64)
Whether you are looking to slow down the moving water of a river or waterfall to create a silky effect, capturing cloud movement as the clouds race across the sky, or simply wanting to smooth out ripples on a lake to create a more serene scene, ND filters will help you achieve this.
30 second exposure with a 10-stop ND1000 filter
What Strength of ND Filters Should I Use?
There are various strengths of ND filter, the most common being the 6-stop (ND64) and 10-stop (ND1000). These are also sometimes known as a Little Stopper and Big Stopper.
Using a 6-stop ND64
The 6-stop (ND64) is useful when the light is lower and is by far the most used in my kit of the two. It is particularly useful around waterfalls and rivers to just extend the shutter speed out to a couple of seconds to get that silky effect.
It's also great to use at seascapes to slow the waves down or to smooth out water on a lake whilst there is still relatively low light in the scene.
St Clair Beach Dunedin. Shot using a 6-stop ND64 filter at 1.3 seconds
You may even find that you can get by without any ND filter at all in very low light around rivers and waterfalls, particularly if there is no sky in the scene to add brightness, sometimes just using a polariser alone is enough.
Using a 10-stop ND1000
The 10-stop comes into its own for VERY long exposures at sunrise or sunset, think up to a few minutes long, or for much brighter daytime scenes where you want to slow the shutter speed more than a few seconds and you simply can't do this with your existing settings.
30 second exposure at Owharoa Falls using 10-stop ND1000 filter
Or you might want to maximise the look of clouds racing across the sky, and the longer you can shoot the better the effect.
Long exposure sunset at Mount Maunganui, 65 seconds using a 10stop ND1000 filter
What to look for in a Neutral Density Filter
The goal of Neutral Density filters in landscapes is to add a sense of surreal into the scene, and you want to ensure that the ND filter you use enhances not detracts from your scene. Using optically pure glass is critical to ensure that your filter doesn't impact the quality of your result. It's also important that an ND filter has:
- A nano coating to repel water and clean easily to prevent the filters getting smeared when shooting around water spray
- Scratch proof and shock proof (though no filters are invincible!)
- No visible colour cast - some filter brands have a decidedly noticeable blue or magenta colour cast particularly with the stronger 10-stop filters which impacts on how you can edit the colours in post processing
Kase Filters uses the highest quality optical glass in all its series of filters whether square or magnetic.
Let's also cover off some of the challenges you might face when using ND Filters
Help! I can't focus with the ND Filter on?
If you are using a very strong ND Filter like a 10-stop, your camera may struggle to auto focus through what is a very dark pair of sunglasses you've just put over your lens. The best way to get around this is to focus without the filter on, switch to manual focus and then add your filter and then slow your shutter speed to compensate. You shouldn't need to refocus until you move to a different spot, or change the focal depth of focus in your image.
Wairepo Arm, Twizel. 20 second exposure with a 10-stop ND1000 filter
How long should I shoot for with an ND Filter on my lens in BULB mode?
More often than not, once you add a 10-stop filter to your setup you'll need to shoot at longer than 30 seconds to allow enough light into your sensor for the shot. This means you will need to shoot in BULB mode using a remote timer to start and stop your shutter - but how long should you shoot for when you can't see the effect of the chosen setting?
Cathedral Cove, 2 1/2 minute exposure with 6-stop ND64 (it was still quite dark)
You can manually work this out if you are smart, a 6-stop means you have to shoot 6 times slower, and a 10-stop means 10 times slower. But when you are out in the field you usually have a million other things to think about like your other camera settings and your composition, especially if the light is changing quickly and you want to capture the scene at its best
This is where using an app like PhotoPills can help. You can plug in your current settings while focusing without the filter on, and then select the correct filter and you'll get the equivalent settings to use. For example,
1/30 second without any filter = 2 seconds using a 6-stop (ND64)
1/30 second without a filter = 30 seconds using a 10-stop (ND1000)
I also suggest that for VERY long exposures of several minutes or more, you can shoot slightly under the suggested time (i.e. if the app says 4 mins you can shoot for 3 minutes or 3.5 minutes), often shooting for the exact length of time once you are shooting for a number of minutes can result in quite an overexposed scene, and the goal is to make sure we don't blow out the highlights in the scene.
Help! I've taken a long exposure and I can see coloured pixels in my image - what's gone wrong?!
What you have described are known as hot pixels, and this is s fairly common occurrence when shooting very long exposures of several minutes, or when shooting at a high ISO.
These are caused by electrical charges that leak into the sensor wells, and they will get worse and appear more frequently when the sensor itself is hot. Typically these are only found when you view your image on screen, and often only when zoomed in. There are several ways to get around this:
- Use LENR (long exposure noise reduction) in camera when shooting long exposures. The downside of this is you have to wait the equivalent length of time that you just shot your image for it to process. This can be TOO long to wait if you have to wait 2 or more minutes for the camera to do this when you're missing the best part of the light.
- Use Photoshop / Noise / Dust & Scratches to remove them in post-processing. Whilst this is a great tool to use, you do need to use the settings with care as it can result in un-sharpening your image.
- Take a dark frame when out in the field and add this step into your post-processing.
What Length of Exposure will Result in the Best Image?
You're the artist, you get to choose. One of the things I love most about using neutral density filters is the freedom it gives you to experiment with a much wider range of shutter speeds than you would otherwise have. Want to shoot a 2 minute exposure? You can. Want to shoot a 2 second exposure? You can. I often shoot both long and shorter long exposures with different strengths of filter so that I have the ability to choose which I prefer when I get back home to edit my shots.
In the example below, shooting at 25 seconds creates a very different feel to the water than 1/2 a second. Around rivers, I often shoot shorter to keep a sense of movement of the flow of the water through the scene.
Riwaka Resurgence 25 second exposure Circular Polariser & ND64
Riwaka Resurgence, 1/2 second exposure Circular Polariser only
When combined with using a circular polariser AND a graduated neutral density filter (check out these posts for more on why these filters are equally important to use in your landscape photography), you have the greatest flexibility to create artistic looking images.
I also think of ND Filters as my 'get out of jail free' card, since they can quickly turn a scene that would otherwise look very plain without filters into a composition with a lot more interest and appeal, and that is something we are all striving for in our work!
A scene that would have been very average without adding filters to smooth the choppy lake and create cloud movement (51 second exposure)
What is the best way to purchase Neutral Density Filters?
Generally the Entry Level Kits all come with a circular polariser, and a 6-stop (and sometimes a graduated filter or 3-stop) and the next level of kit then adds in a 10-stop ND filter but these can always be purchased individually as well.
For more assistance on which filter setup will be right for you and your photography, read our Filter Buying Guide.