If you’ve ever looked at a landscape shot and asked yourself why the image looks a certain way, chances are the answer is filters. Sure, processing plays a role, but in landscape photography filters allow you to take greater control of how elements within a scene are captured, for both exposure control and creative effects making them an invaluable tool for the majority of landscape photographers.

The three main types of filters that are available are screw-in, magnetic and square filters. Screw-in filters simply screw onto the front of lenses and need to be the same size as the lens’ filter thread. It’s not impossible to stack these filters, to use two at once, but this can cause vignetting and other issues. Magnetic filters are similar to the screw-in type, but you screw an adapter ring onto the front of the lens and the thin filters can then be magnetically attached. These stack more effectively than screw-in filters and provide convenience alongside space savings.

"If you’ve ever looked at a landscape shot and asked yourself why the image looks a certain way, chances are the answer is filters."

The most popular type of filters for landscape photographers are square filters which are sheets of optical glass or resin held in place using a filter holder attached to the front of your lenses. The advantage of these is that one holder can be attached to multiple lenses using the compatible adaptor ring and, as well as a polarising filter, you can often attach up to three additional filters. The most important aspect of this filter type is that they allow for the use of ND grads (neutral density graduated filters). We’ll go into more detail later but in a nutshell, these filters require the ability to have their vertical position adjusted according to the level of the horizon, which isn’t possible if using screw-in or magnetic filters.

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Filters for landscape photography

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Polarising filter

The humble polarising filter is one of the most important filters available; if you could only have one filter it would have to be this, forget the rest. Well, don’t take that literally, but there are several good reasons why polarising filters are so important, and the first is that their effects cannot be replicated in editing software – it’s simply not possible. Whereas long exposures where you’d use ND filters and images balanced with ND grads can be replicated using other techniques.

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So, what can you do with a polarising filter? These filters polarise light and are most effective when the camera lens is at a 90° angle to the sun. To adjust their effects, you simply rotate the front part of the filter if using a screw-in polariser, or sometimes rotate a dial to turn the filter when used in a filter holder. By doing this you can do five things: you can deepen blue skies, remove glare and reflections from surfaces, reduce the harshness of light, increase saturation and since a polariser can reduce light entering the lens between 0.5-1.5 stops, they can also be used as a low strength ND filter. But not all effects will work at the same time since they depend on the filter being rotated to a specific position.

ND filters

Neutral density filters come in a variety of light reducing densities that reduce the amount of light that can enter the lens. The advantage of this is that you can shoot at slower shutter speeds for blurring elements in the scene such as water, clouds or crops in fields, plus you can shoot at wider apertures in bright conditions. Neutral density filters, as the name suggests, are neutral with no effect on colour in images. This is often true for standard NDs, but when it comes to extreme NDs colour casts are common with even the most expensive filters available.

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Editor's tip:

See our video tutorial on how to correct colour casts with extreme NDs.

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Different filter companies use a variety of ways to label their ND filters, which can be confusing to even experienced photographers. Here’s a breakdown of the three different ways ND filters can be labelled:

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Types of ND filters

Normal NDs are those that you simply attach to the lens and shoot as normal with no need to calculate exposure because they don’t interfere with metering. These are typically available in two, three and four-stop densities, with three-stop NDs being the most popular option for a fixed strength filter.

Extreme NDs are filters with stronger light-reducing densities and provide six (Little Stopper), 10 (Big Stopper) and 15-stop (Super Stopper) light-reducing densities. These typically create colour casts in images and require that you calculate exposure. This is because they can trick camera metering systems, and their light blocking capabilities often require manually timed exposures that can be minutes long and require you to shoot in Bulb mode.

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Variable NDs are screw-in filters that rotate to change the strength of the filter and are popular because you have one filter capable of reducing exposure at varying degrees. One thing to watch out for with these filters is that at their full strength they create an X in the centre of the frame.

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ND graduated filters

One of the biggest challenges in landscape photography is balancing the exposure between a bright sky and an often significantly darker foreground. It’s less of a challenge if you have the right tools, and that’s where square ND grads come into play. These filters reduce light entering the lens at the top of the frame to effectively darken the exposure of the bright sky, graduating in the middle of the filter to no effect at the bottom so the ground remains unaffected. ND Grads work best when the square type of filter because you can adjust the position of the graduation depending on the position of the horizon in the frame.

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The graduations available include Soft for hilly and mountainous areas, Medium for scenes where several elements protrude into the sky, Hard for flat horizons such as the coast and Reverse ND grads for shooting around sunrise and sunset. Reverse grads graduate from full strength and a hard edge in the centre of the filter where the sky meets the horizon, with a soft graduation to no effect at the top of the filter. This is designed to reduce exposure most above the horizon which is typically the brightest part of the sky around sunrise and sunset.
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For many landscape photographers, a 4-stop Soft GND, 3-stop Medium GND, 2-stop Hard GND and a 3-stop Reverse GND will cover most, if not all situations. Some photographers, however, prefer to use smaller and lighter screw-in or magnetic filters to reduce the amount of kit carried, so to balance the exposure between a bright sky and darker ground they shoot and process HDR (high dynamic range) images.

HDR requires that three or five bracketed exposures at two-stop increments are taken to capture detail from the darkest shadows to the brightest highlights, which are then merged together during post-processing in Lightroom or specialist HDR software. The results can look incredibly natural, but because additional images and processing are required, most professional landscape photographers prefer to use drop-in filters and ND grads.

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Editor's note:

Learn how to create HDRs in Lightroom & Photoshop with our video tutorial.