Smartphone filters: all about ND and CPL filters for your phone

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Smartphone filters: alles over ND- en CPL-filters voor je telefoon

Smartphone filters give you more control over the light entering your phone's camera. For example, they help reduce reflections on water, prevent overexposure in bright sunlight, and capture more natural motion in videos.

But which smartphone filter do you need? What's the difference between an ND filter and a CPL filter? And when do you choose a fixed ND16 filter or a variable ND2-32 filter?

In this blog, we'll explain step-by-step how smartphone filters work and which filter suits the photos and videos you want to create.

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What are smartphone filters?

Smartphone filters are physical filters made of optical glass that you place in front of your phone's camera. The filter influences the light before it reaches the camera sensor.

This is different from a digital filter in Instagram, TikTok or your photo app. A digital filter adjusts, for example, colours, brightness or contrast afterwards. A physical camera filter changes the light during the capture itself.

This allows you to achieve effects that you cannot always perfectly recreate afterwards. A CPL filter can reduce real reflections on water. An ND filter ensures that physically less light reaches the camera sensor.

The two most well-known smartphone filters are:

  • CPL filters for reducing reflections and glare;
  • ND filters for reducing the total amount of light.

Why do you use a filter on your phone?

Your smartphone camera usually adjusts the exposure automatically. This works well in normal conditions but gives you less control when shooting in bright sunlight, by water, or through glass.

Smartphone filters are especially useful when you want to:

  • film outdoors in bright sunlight;
  • reduce reflections on water or glass;
  • capture landscapes with deeper colors;
  • create smoother motion in video;
  • shoot with a longer shutter speed during the day;
  • have more control over manual camera settings.

Which filter you need primarily depends on the problem you want to solve.

What does a CPL filter do for your smartphone?

CPL stands for Circular Polarizer, which is a circular polarizing filter. A CPL filter reduces polarized light and therefore helps to limit reflections and glare.

This works especially well with reflections on non-metallic surfaces, such as:

  • water;
  • glass;
  • wet leaves;
  • painted surfaces;
  • wet roads.

For example, if you're filming a lake, but mainly see a white glare on the water, by rotating a CPL filter, you can reduce that reflection. This makes details in or under the water more visible.

A CPL filter can also create deeper colors. Blue skies become darker, clouds stand out more, and green leaves gain more detail. This is because the filter reduces distracting reflections and scattered light.

Canon also explains in its explanation of polarizing filters that a polarizing filter can reduce reflections from, among other things, leaves and create more contrast in the sky.

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  • Telesin CPL Filter voor Telesin Lens Case - Lenzen

    When do you use a CPL filter?

    A CPL filter is particularly suitable for:

    • landscape photography;
    • holiday photos by the sea;
    • filming by lakes and rivers;
    • photography through a window;
    • car and product photography;
    • outdoor videos after rain;
    • photos of plants and leaves.

    The result depends on the direction of the light and the angle at which you are filming. Therefore, slowly rotate the filter while looking at your phone's screen. You will immediately see the effect on reflections and colors change.

    Do not automatically use a CPL filter for every shot. The filter also blocks some of the light. In the evening, indoors, or in low light, your phone may therefore choose a higher ISO or longer shutter speed. This can cause additional noise or motion blur.

  • Telesin CPL Filter voor Telesin Lens Case - Lenzen

    Telesin CPL Filter for Smartphone

    The Telesin CPL Filter for Telesin Lens Case is a magnetic smartphone filter with a diameter of 58 mm.

    You attach the filter magnetically to a suitable Telesin lens case. Then you rotate the filter to adjust the polarization effect.

    The main features:

    • reduces reflections on water and glass, among other things;
    • helps make colors and details more visible;
    • adjustable in five levels;
    • magnetic attachment;
    • diameter of 58 mm;
    • made of hardened AGC glass;
    • features a multi-coating;
    • includes cleaning cloth and manual.

    Please note: this filter is specifically designed for Telesin smartphone lens cases. The filter has not been tested on lens cases from other brands.

What does an ND filter do for your smartphone?

ND stands for Neutral Density. An ND filter reduces the total amount of light entering the camera. The filter is designed to block light evenly, without significantly altering the colours of your image.

You can compare an ND filter to sunglasses for your smartphone camera.

Less light may not immediately sound like an advantage. However, it gives you more control over the shutter speed and exposure of your shot. This is especially important when filming in bright sunlight.

Without an ND filter, your phone often automatically chooses a very short shutter speed outdoors. Every movement is then captured extremely sharply. This can make a video appear jerky or unnatural.

With an ND filter, you can use a longer shutter speed. Moving subjects then get a small amount of natural motion blur, making movements appear calmer and smoother.

In its explanation of ND filters, Adobe explains how an ND filter allows less light to pass through, enabling longer shutter speeds in bright light.

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  • An ND filter for smartphone video

    The 180-degree rule is often used for natural-looking motion blur. This involves setting a shutter speed that is approximately twice as fast as the frame rate.

    For example, use as a starting point:

    • 25 fps with a shutter speed of approximately 1/50 second;
    • 30 fps with a shutter speed of approximately 1/60 second;
    • 60 fps with a shutter speed of approximately 1/120 second.

    The 180-degree rule is not a strict requirement, but a commonly used starting point for natural-looking motion. You can find more information about this in RED's shutter angle tutorial.

    In bright sunlight, your image with these settings will quickly become overexposed without an ND filter. An ND filter blocks light, allowing you to use the desired shutter speed.

    For this, you preferably need a camera app or camera mode that allows you to manually set or lock the shutter speed and ISO. In fully automatic mode, your phone may compensate for the dark filter by changing other settings.

  • An ND filter for smartphone photography

    An ND filter can also be useful in photography. Because less light enters, you can use a slower shutter speed during the day.

    With this, you can, for example:

    • capture flowing water more softly;
    • blur the movement of clouds;
    • create light trails;
    • blur people or vehicles in motion;
    • create creative long exposures.

    Always use a sturdy phone tripod when using a slower shutter speed. Even a small movement of your phone can make the entire photo blurry.

    An ND filter does not automatically make your photo better or sharper. It primarily gives you more control over the settings with which you create the desired effect.

What do ND2-32 and ND16 mean?

ND filters are available in different strengths. The higher the ND number, the less light the filter transmits.

The most common designations are:

  • ND2: reduces light by 1 stop;
  • ND4: reduces light by 2 stops;
  • ND8: reduces light by 3 stops;
  • ND16: reduces light by 4 stops;
  • ND32: reduces light by 5 stops.

Each stop less light means that the amount of incoming light is halved.

An ND16 filter therefore transmits 1/16 of the original amount of light. That is 6.25%. Whether ND16 is the right strength for your situation depends on the amount of light, your framerate, shutter speed, and ISO.

A variable ND2-32 filter combines different filter strengths in one filter. By rotating the outer ring, you set the filter between one and five stops of light reduction.

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  • Telesin Variabel ND Filter ND2-32 voor Telesin lenscase - Lenzen

    Telesin Variable ND2-32 Filter for Smartphone

    The Telesin Variable ND Filter ND2-32 for Telesin Lens Case provides an adjustable range from ND2 to ND32.

    This allows you to adjust light reduction from one to five stops. The filter has a diameter of 58 mm and is magnetically attached to a suitable Telesin lens case.

    Key features:

    • variable filter strength from ND2 to ND32;
    • suitable for photography and video in bright light;
    • magnetic attachment;
    • diameter of 58 mm;
    • made of hardened AGC glass;
    • features a multi-coating;
    • includes cleaning cloth and manual.

    Please note: this filter is also specifically designed and tested for use with Telesin smartphone lens cases.

  • Telesin Master Grip voor Samsung S26 Ultra - Creator Combo met lamp en filter - Zwart - Handgrips

    Telesin Master Grip with ND16 filter for Samsung Galaxy S26 Ultra

    Do you use a Samsung Galaxy S26 Ultra and are you looking for not just a filter, but a complete camera setup? Then the Telesin Master Grip for Samsung Galaxy S26 Ultra – Creator Combo is an interesting option.

    This set comes with a fixed ND16 filter. The filter reduces the amount of light by four stops and is particularly suitable for situations with abundant and relatively constant daylight.

    The Creator Combo consists of:

    • a Telesin Master Grip;
    • a matching phone case for the Samsung Galaxy S26 Ultra;
    • a fixed ND16 filter;
    • a magnetic flash;
    • a wrist strap;
    • a charging cable;
    • a manual.

    The grip has a physical shutter button and a zoom wheel. This means you have to touch the screen less often while filming or taking photos.

    In addition, the grip has a built-in power bank with a capacity of 3200 mAh. This allows you to recharge your Samsung Galaxy S26 Ultra during longer shoots. There is also a 1/4 inch screw hole on the bottom for mounting on a tripod.

    This combination is particularly interesting if you film with a Samsung Galaxy S26 Ultra and want to use a suitable grip, lens case, lighting, and ND filter directly.

Fixed or variable ND filter: what's the difference?

A fixed ND filter has one fixed strength. An ND16 filter, for example, always reduces light by four stops.

A variable ND filter can be adjusted. With an ND2-32 filter, you turn the outer ring to set the light reduction between one and five stops.

Choose a fixed ND16 filter when you:

  • mainly film in bright daylight;
  • work with fairly constant lighting conditions;
  • want a simple filter without extra settings;
  • already know that four stops of light reduction suits your settings.

Choose a variable ND2-32 filter when you:

  • film in varying light conditions;
  • want to quickly switch between sun and shade;
  • use different frame rates and shutter speeds;
  • want more control over the exact light reduction.

A variable ND filter is more flexible. A fixed ND filter is simpler and prevents you from accidentally changing the strength during filming.

What is the difference between ND and CPL filters?

An ND filter and a CPL filter are both placed in front of the camera, but solve different problems.

Choose a CPL filter when you want to:

  • reduce reflections on water or glass;
  • get deeper colors in landscapes;
  • capture more detail in foliage or wet surfaces;
  • photograph through a window;
  • limit glare from shiny surfaces.

Choose an ND filter when you have:

  • too much light;
  • want to film with a fixed, longer shutter speed;
  • want more natural motion blur in video;
  • want to take long exposures during the day;
  • want to manually control your exposure.

In short: a CPL filter controls reflections, while an ND filter reduces the total amount of light.

An ND filter is therefore not a substitute for a CPL filter. Do you primarily want to reduce glare on water? Then choose a CPL filter. Do you want to film in full sun with a shutter speed of 1/50 second? Then choose a suitable ND strength.

What smartphone filters do you need?

The best smartphone filter depends on what you want to photograph or film.

  • Holiday by the sea

    Do you want to photograph the sea and reduce reflections on the water? Then choose a CPL filter. This can make details in the water, the sky, and the surroundings more visible.

    Do you mainly film moving images in bright sunlight? Then an ND filter is more practical.

  • Landscapes and Nature

    For landscapes, a CPL filter is usually the best first choice. The filter can reduce reflections on leaves and make colours and clouds stand out more.

    For long exposures of a waterfall, flowing water, or moving clouds, you will need an ND filter.

  • Vlogs and cinematic smartphone videos

    Filming outdoors and want to use a fixed shutter speed? Then a variable ND filter is usually the most flexible option. You adjust the strength to the available light without having to constantly change filters.

    Are you mainly filming in constant, bright daylight? Then a fixed ND16 filter might be sufficient.

  • Samsung Galaxy S26 Ultra

    Do you use a Samsung Galaxy S26 Ultra and want not only a filter but also more grip, physical camera controls, lighting, and extra battery capacity? Then the Telesin Master Grip Creator Combo is the most complete option from this blog.

    The included ND16 filter blocks four stops of light. Please note that this strength is not adjustable.

  • Automotive and product photography

    For glossy or lacquered surfaces, a CPL filter can reduce annoying reflections. The result varies depending on the material and shooting angle. Therefore, check what changes on the screen while turning the filter.

  • Photographing in the evening

    In low light, you usually don't need an ND filter. A CPL filter also blocks light and may not always add value in such situations.

    Therefore, remove the filter when you don't need its specific effect.

How do you attach smartphone filters to your phone?

A regular camera filter cannot be directly attached to every smartphone. You need a lens case, filter holder, clamp, or other suitable mounting system.

The individual Telesin CPL and ND2-32 filters in this blog work with suitable Telesin smartphone lens cases.

Attaching them works as follows:

  1. Place your phone in the appropriate Telesin lens case.
  2. Clean the camera lens and the filter.
  3. Magnetically attach the filter to the filter mount.
  4. Open the camera app.
  5. Check that the filter is properly positioned in front of the camera lens being used.
  6. Rotate the filter to set the desired effect.
  7. Check the exposure and the edges of the image.
  8. Only then start taking photos or filming.

The Telesin Master Grip Creator Combo comes with its own phone case for the Samsung Galaxy S26 Ultra and a matching ND16 filter.

Do you use multiple cameras on your smartphone, such as a main camera, telephoto lens, and ultra-wide-angle lens? Then test each lens separately.

The field of view and automatic camera switching can vary per phone. With a very wide field of view, the edge of a filter may sometimes become visible. This is called vignetting.

Practical tips for using smartphone filters

A smartphone filter only works properly when the glass is clean, the filter is correctly adjusted and your camera is not constantly changing its settings.

Run through these eight checks before recording or taking photos. They help prevent unwanted reflections, uneven exposure, automatic lens switching and blurred shots.

  1. Test without the filter first

    Make a short test shot without the filter. This makes it easier to see whether the filter genuinely improves the image.

  2. Clean the lens and filter

    Remove dust, sand and fingerprints with a clean microfibre cloth before attaching the filter.

  3. Do not automatically maximise the CPL effect

    Rotate the filter slowly and stop once reflections are sufficiently reduced. The strongest setting is not always the best.

  4. Set up the camera first

    Choose your frame rate, shutter speed and ISO before adjusting the ND filter to the available light.

  5. Check the variable ND filter

    Inspect the complete image for dark or uneven areas, especially when the variable ND filter is near its darkest position.

  6. Lock your camera settings

    Lock focus, white balance and exposure to prevent visible changes while recording.

  7. Use a tripod for long exposures

    Place your smartphone on a stable tripod and use a timer or Bluetooth remote to prevent camera movement.

  8. Check which camera lens is active

    Check which smartphone camera is being used and prevent automatic lens switching whenever possible.

ND16 tip: A fixed ND16 filter always reduces light by four stops. If the image is too dark, you need to remove the filter.

Conclusion: which smartphone filter is right for you?

Smartphone filters help you gain more control over the light entering your phone's camera. It's important to choose the right filter for the situation.

Use a CPL filter when you want to reduce reflections on water, glass, or wet surfaces. This filter can also provide deeper colors and more visible details in landscapes.

Use an ND filter when you want to reduce the total amount of light. This allows you to film with a longer shutter speed in bright sunlight or capture creative long exposures during the day.

Choose a fixed ND16 filter when four stops of light reduction suit your settings and you primarily work in constant daylight. Choose a variable ND2-32 filter when you need more flexibility with changing light conditions.

The following Telesin products are available:

So, don't just pick the darkest filter. First, determine what problem you want to solve, how much light you need to block, and which mounting system is suitable for your smartphone.

Frequently Asked Questions

What do smartphone filters do?

Smartphone filters affect the light before it reaches the camera sensor. Depending on the type of filter, you can reduce reflections, limit the amount of light, or gain more control over the shutter speed.

What is the difference between an ND filter and a CPL filter?

An ND filter reduces the total amount of light entering the camera. A CPL filter reduces certain reflections on water and glass, among other things, and can make colours appear more intense.

Which smartphone filter do you use against reflections?

Use a CPL filter to reduce reflections on non-metallic surfaces such as water and glass. Rotate the filter while looking at the image to find the desired setting.

Which filter do you use for smartphone video in bright sunlight?

For video in bright sunlight, use an ND filter. This allows you to set a slower shutter speed without the shot being immediately overexposed.

A variable ND2-32 filter is flexible when light changes. A fixed ND16 filter is suitable when four stops of light reduction fit your settings and lighting conditions.

What does ND16 mean?

An ND16 filter reduces the amount of incoming light by four stops. The filter allows 1/16, or 6.25%, of the original amount of light to pass through.

What is the difference between ND16 and ND2-32?

An ND16 filter has a fixed light reduction of four stops. A variable ND2-32 filter can be set between one and five stops.

A variable filter is therefore more flexible in changing light conditions. A fixed ND16 filter is simpler when working in reasonably constant light.

Does a Telesin filter fit every smartphone?

No. The separate Telesin CPL and ND2-32 filters are designed for Telesin smartphone lens cases.

The Telesin Master Grip Creator Combo from this blog is specifically designed for the Samsung Galaxy S26 Ultra and comes with a matching phone case.

Do you need a special camera app for an ND filter?

You can use an ND filter with the standard camera app. For full control over motion blur, a camera app or camera mode with manual settings is better.

This allows you to set or lock the shutter speed, ISO, focus, and white balance, among other things.

Are smartphone filters suitable for night photography?

Usually not. Both ND and CPL filters block some of the light. In low light, this can lead to additional noise or motion blur.

Therefore, remove the filter when you don't need its effect.

Can you add the effect of a CPL filter in post-processing?

You can adjust colours and contrast afterwards, but you usually cannot completely remove actual reflections captured during shooting.

Therefore, it is better to use a CPL filter directly during shooting.

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