The 3 essential camera filters (and how to use them)

There are some people out there who think that using camera filters is cheating. But there are numerous occasions when a lens filter can and should be used to improve your photograph and ensure it is captured correctly. 

What we see with our eyes is different from what we can capture in camera, and the camera is in some ways far more limited than the human eye but superior in others. 

So, in this article, we give you a rundown of the three most useful camera filters and how to use them correctly and creatively. 

 

1. Polarising filter

The polarising filter is often considered to be the king of all filters. 

It’s certainly the one we use the most, and rarely off our lens. It’s probably the only filter that cannot be replicated in Photoshop or other photo editing software. 

 

What does a polarising filter do? 

OK, so technically, it’s like this. A polariser’s principle function is to control the direction of polarised light, which is light that vibrates in a specific plane. It does this by allowing light waves oscillating in a particular direction to pass through while blocking or reducing light waves oscillating in other directions.

On a not-so-technical note, it blocks unwanted light rays often caused by reflections on non-metallic surfaces such as water, glass or wet leaves. Blocking the reflected light reduces glare and darkens otherwise bright areas. 

Related: When to use a telephoto lens (and its effects)

 

Benefits of using a polarising camera filter

 

1. Boost colour and contrast

A polariser can enhance the vibrancy of colours and increase the overall contrast in a scene. 

Reducing glare caused by reflections allows a subject’s colour and detail to become more visible, resulting in a more vibrant and captivating photograph. 

This is excellent when photographing trees, leaves and vegetation, especially when wet. By reducing the glare, you can darken the colours.

 

2. Darkening skies

One of the most common uses of a polariser is to darken blue skies. This effect is a great way to add definition to the clouds and make them stand out against the blue sky.

 

3. Eliminating reflections on water

The polariser is commonly used for controlling or eliminating light reflected on the surface of water, particularly on lakes, rivers or the sea. 

You can use it to darken the water's surface when it’s too bright and eliminate reflections. 

 

4. Enhancing reflections on water

Another lesser-known use is to enhance an image or colours reflected in the water. This may seem strange, as we just explained how it can eliminate reflections. 

A circular polariser will eliminate a reflected image when turned fully. However, when you turn it back slowly to reduce the intensity of the polarisation, you can reach a point where you have reduced enough glare to make the reflected image much bolder and sharper. 

Related: The ultimate guide to night city photography

 

How to use a polariser

There are two types of polarising camera filters—linear and circular. The linear one, you simply put on the lens. The circular polariser can be rotated on the lens to vary the polarisation strength.

The effectiveness of the polariser varies depending on the angle of the light source relative to the camera and the angle of the filter itself. 

Consequently, these filters work best when shooting your subject at a 90-degree angle to the sun or other strong light sources.

See the effect of a polariser on skies here.

 

2. ND (neutral density) filter

A neutral density filter is essentially a darkened piece of glass that reduces the light entering the lens and falling upon the sensor or film.

In a nutshell, it fools the camera into believing the scene is darker than it actually is, making them an essential camera filter for improving your technique. 

 

What is an ND filter used for?

So why would you want to make the scene darker? The primary reason is to force a longer exposure or a wider aperture than would otherwise be possible in bright light without overexposing the image.

 

Creative long exposures

Landscape photographers use long exposures to achieve creative blur effects, typically on moving clouds or flowing water such as rivers, rapids and waterfalls. 

Additionally, a super long exposure can smooth out water so much it appears like ice or mist. All this is easily done when the light is naturally low, like dusk or dawn. 

However, during the day, when there is too much light or shooting into the bright sunset or sunrise, achieving a long enough exposure is impossible. That’s where the ND filter comes in.

ND filters come in varying strengths, usually measured in stops. In photography, when light is reduced by one stop, you cut the light by one-half. 

Conversely, if you increase by one stop, you are doubling the amount of light. You need to increase your exposure time by one stop when the light is one stop less.

So, if your nominal exposure time is 1/60th sec, and you put a one-stop ND filter on, then you need to increase your exposure time to 1/30th sec.

You can reduce your shutter speed by reducing the light for a longer exposure. 

Typically a landscape photographer will use a 3-stop, 6-stop or, for super long exposures, a 10 or 15-stop. A 10-stop ND filter will turn a 1/60th second into a 16-second exposure.

Watch a video using a 10-stop ND filter here.

 

Using wider apertures

Sometimes you want to use a very wide aperture to reduce your depth of field for portrait or macro photography. Sometimes the light may be too bright to allow you to open your aperture up to its widest point. 

This is another instance where an ND filter is useful. Although, in this case, you are more likely to use a 1,2 or 3-stop ND to bring it down enough to widen the aperture but still allow a relatively fast shutter speed if you want to freeze your subject.

Or, in some cases, reduce the shutter speed enough to get a small amount of motion blur for action or sports photography.

Related: A guide to getting the right shutter speed

 

3. ND grad filters

An ND grad filter is similar to an ND in that it is darkened to stop down the light. 

However, in the case of an ND grad, only one half is darkened, whereas the other is clear. 

The idea of an ND grad is to darken down one half of your composition, typically the sky, which can often be much brighter than the foreground. 

It comes down to something called dynamic range. Dynamic range is the range of brightness within a scene, from the darkest to the brightest point, which can record detail in both the shadows and highlights. 

Anything outside of that range is blank with no detail. Camera film and modern-day sensors have a smaller dynamic range than the human eye. 

We can see much more detail in a scene with extremely bright and dark areas, whereas the camera cannot. Some higher-end modern cameras have a wider dynamic range than others but less than the human eye. 

Take looking at a scene where the sky is much brighter than the land, for example. While you can see all the detail yourself, when you take a photo, either the sky is overexposed, or the land is underexposed. 

This is where we can use an ND grad filter. By positioning the dark part of the filter over the bright sky, we can darken that sky and bring balance back to the scene, making them one of the best camera filters for shooting professional photos. 

Essentially we are evening out the brightness and reducing the scene's dynamic range. 

Just like the ND filter, ND grads come in varying strengths. However, they don’t go as extreme because we are not trying to get long exposures, just even out the brightness.

Typically the most you will need is a 3-stop. In some extremes, you might need a 4 or 5-stop. You can get filters this strong, but it’s better to have a set of 1, 2 & 3, and then you can stack them if necessary.

 

Different graduation types 

As well as the strength, an ND grad camera filter also comes in different graduation types. The graduation is the transition between the clear part of the filter and the darkened section. Depending on your chosen type, the transition can be hard, medium or soft.

 

1. A hard grad

The transition is sharp and noticeable on a hard grad, creating a distinct separation between the light and dark portions. 

This is ideal for scenes where the change between the land and sky is abrupt, such as the horizon over the sea. There is a clear horizontal line where the sky meets the sea, forming a hard transition from bright to dark. 

However, it’s not only for seascapes. A hard grad can be used over landscapes where the distant hills or mountains do not protrude so high into the sky. 

These filters are ideal for use wherever the horizon in your scene is clearly defined and the separation between the land and the sky is clear.

 

2. A medium grad

A medium ND grad has a slightly smoother transition but is still noticeable. The gradual transition provides a gentler blend between the dark and clear portions. 

A medium grad is ideal for scenes where the horizon is not perfectly flat but still relatively defined, such as close-up mountainous scenes or city skylines.

Related: How to become a professional photographer

 

3. A soft grad

A soft grad has the smoothest and most gradual transition of all. The transition is almost seamless and provides a soft blending effect that is barely noticeable. 

Soft filters are ideal when the horizon line is uneven or when objects like large trees or tall buildings protrude well into the sky within your frame. Soft grads are typically used in woodland or cityscape photography.

 

Camera filters still have their uses

In the digital age, many are throwing away their filters and opting for other techniques, such as exposure blending (taking three bracketed exposures to compensate for the high dynamic range and blending them in post-processing) rather than using grads. 

Instead of an ND to get a long exposure, you can shoot multiple exposures sequentially and blend them in post-processing. 

However, all this takes time and more clicks of the shutter. A camera filter will get all this in one shot, and you get the satisfaction of seeing the result on your viewscreen immediately. Plus, it’s a lot less work!

 

Specialist photography insurance through Ripe Photography 

Heading out to experiment with your new camera filters? You may want to protect your camera and accessories through specialist photography insurance. 

At Ripe, we arrange bespoke cover that can be tailored to fit your exact requirements, so you only ever pay for what you need. You can cover up to £60,000 of equipment for theft and accidental damage so that you can continue your shoots with peace of mind. 

Click here to learn more about specialist camera insurance, or hit the button below to get an online quote today.