Essential Filters for Landscape Photography

In this digital age, do we still need filters? With the right skills, you can practically do anything in Photoshop, so are in-camera filters now a little antiquated? We don’t think so and there are still benefits of using physical filters for corrective and creative purposes. Let’s have a look at the three filter types that remain a must-have for landscape enthusiasts.   

Polarising filters

However good your post processing skills are, you can’t replicate the effect of a polariser in Photoshop. The only way your shots will benefit from the polarised look is by filtering the scene at the time you trigger the shutter. A polariser is designed to reduce glare and reflections from non-metallic objects. They restore natural colour saturation and are best known for the way they deepen blue skies and make cloud appear more pronounced. They work by blocking polarised light from entering the lens and most polarisers are circular, screw-in type filters, which attach directly to the lens or via a filter holder. They are constructed from a piece of polarising material sandwiched between two pieces of optical glass. Unlike other filters, you can rotate the filter in its mount – doing so alters the amount of polarised light allowed to pass through. If you peer through the viewfinder – or use LiveView – while rotating the filter, you should clearly see the filter’s effect. Reflections will come and go and the intensity of colour will strengthen and fade. The filter is at its most effective used at 90degrees to the sun – known as Brewster’s angle – the area where there is most polarised light. By reducing glare and reflections, it is also a great filter for shooting woodland interiors – the filter will add attractive natural vibrancy and punch to images.

There is no secret formula to how best to use a polariser – you simply rotate the filter until you achieve the effect you desire. A word of warning, though. The filter is very seductive and you can overdo the effect. Over-polarised skies are a common problem, when clear blue skies appear over saturated and artificially dark. Therefore, always use with care and don’t feel you always need to fully polarise a scene – just pullback a little. After all, a landscape shouldn’t look filtered – the effect should be authentic and believable.

Solid Neutral Density (ND) filters

Most landscape photographers like the effect of subject motion created by the use of longer exposures. In low light, shutter speeds will be naturally long. However, at other times of day, the only way to generate an exposure long enough to blur subject motion – like flowing water, scudding clouds or swaying crops – is by attaching a solid ND filter. They might look like boring, grey filters at first glance, but by absorbing light, they allow photographers to be more creative. They are available as either screw-in or slot-in type filters and in a range of different densities, from 1-stop up to extreme 15-stop versions.

Neutral density filters are particularly popular for coastal photography. They will reduce rough seas to a glassy blur and render scudding cloud as brushstrokes of colour. Yes, maybe they are somewhat overused today, but when applied well and appropriately, their effect on a scene can be stunning. Again, you can’t successfully mimic the filter’s effect in post, so if you enjoy this style of landscape photography, you will need physical filters.

ND filters with a density up to 6-stops are simple enough to use, with the camera’s TTL metering adjusting automatically for their strength. For extreme NDs, with a density of around 10-stops, you will normally need to calculate exposure length manually. Try using an App like the LEE Stopper App to help you with your calculations. If shutter length exceeds 30-seconds, you may need to switch to your camera’s Bulb or B setting and lock the shutter open manually (using a remote or infrared device) for the desired length.

Graduated Neutal Density filters

Graduated ND filters have long been an essential landscape filter. They are half clear, half coated, with a transitional zone where the two halves meet. Like a solid ND, they are designed to absorb light, but instead of altering the entire image, they just block light from one area – typically the sky. Why? Well, the sky is usually lighter then the landscape. The contrast in brightness between the two can be the equivalent of several stops of light – particularly around sunrise and sunset due to the sun’s lower position. The level of contrast can be so great that it exceeds the capabilities of the camera’s dynamic range. Therefore, if you meter correctly for the foreground, the sky will be too light and overexposed; but if you expose correctly for the sky, the landscape will be recorded too dark. It is a common headache with two main solutions – one in-camera, the other using software.

The in-camera answer is to use a grad. They are rectangular slot-in type filters that attach via a filter holder. You can then slide them into position, carefully aligning the transitional zone with the horizon. By doing so, you can balance the light and bring the entire scene within the sensor’s dynamic range – capturing detail in both the shadow and highlight areas. You can buy grads in different densities, with either a soft- medium- or hard-edge.

ND grads with a medium or soft-edge are best suited to scenes with an uneven horizon – for example, when mountains, hills, buildings or a tree interrupt the skyline. This is because, due to the larger feathered zone, the filter won’t noticeably or abruptly darken objects breaking the skyline. A hard-edged ND grad is better suited to scenes with a straight horizon, like a seascape. It can be aligned with far more precision and allows you to reduce the brightness of the sky with greater accuracy. 

Although it is always satisfying to get things right in-camera, there is an alternative to using grads. Instead, you can capture two (or more) frames using different exposures and later merge them together in Lightroom or Photoshop to achieve one correctly exposed result. 

Verdict:

In our opinion, landscape filters remain essential and are here to stay. We demonstrate the use and benefits of using filters throughout our Dawn 2 Dusk Photography workshops. If you have never used filters before - or are just unsure how to get the best from filters you own - why not join one of our workshops and learn from the pros?