Drones are an amazing tool for capturing aerial footage and photos, but getting the right exposure can be a challenge, especially in hard conditions like the bright midday sun. This is where Neutral Density (ND) filters come in. In this blog post, I’ll explain what ND filters are and how they can help you get the best shots with your drone.
First of all, what exactly are ND Filters?
ND filters are quite simple really, they’re basically pieces of glass or plastic that reduce the amount of light entering the camera lens. By reducing the amount of light coming in, ND filters allow you to use slower shutter speeds, which can be particularly useful to help capture smooth, cinematic footage and motion blur with a drone. They come in a range of strengths, expressed as stops of light reduction, and are usually measured in terms of Optical Density (OD). The most common strengths of ND filters for drones are 2, 4, 8 and 16, which correspond to 2, 4, 8, and 16 stops of light reduction, respectively.
How Do ND Filters Work with a Drone?
Let’s use the example of bright, sunny conditions. It can be difficult from a high aerial perspective to not over-expose because the drone’s camera will be trying to balance the amount of light and shadow in the image, which can result in blown-out highlights and unbalanced colors.
Using an ND filter as previously mentioned slows the camera’s shutter speed which drastically helps to minimize over-exposing your shots. Slower shutter speeds also allow you to capture smoother, more cinematic footage as well as helping to keep your images looking balanced and professional.
In addition to helping you get the right exposure, ND filters also help to reduce lens flares and ghosting, which can occur when shooting into the sun. This makes them especially useful for capturing sunrise and sunset shots, as well as for shooting over water, where reflections and glare can be a problem.
What about ND/PL filters?
ND/PL Filters are both Neutral Density (ND) and Polarizing (PL). Like I’ve previously stated, the ND filter can reduce light, while the polarizing component can help reduce glare and reflections from non-metallic surfaces such as water or glass. It works by only allowing light waves in a particular direction to pass through the filter, resulting in richer colors, increased contrast, and a more vibrant image. This makes PL filters particularly useful when shooting over water or in bright sunlight. One word of warning though, polarization will really affect the look of shots if the drone is continuing to shoot video whilst changing angles with the sun or light source. Try to minimize this if you want consistent looking footage.
Choosing the Right ND Filter for Your Drone
When choosing an ND filter for your drone, it’s important to consider the conditions you’ll be shooting in and the type of footage you want to capture. For example, if you’ll be shooting in those bright, sunny conditions, you may need a stronger ND filter, such as an ND8 or ND16, to get the right exposure. If you’ll be shooting in more average lighting conditions like on a day with clouds or overcast, an ND4 filter or no filter may be sufficient. In most situations though I find myself using the ND16/PL with a little bit of polarization, however if I want to look down through the water of a lake or ocean I’ll typically up the polarization to its max. The best thing to do is continually experiment and see what matches with your style and the scene and subject of what you’re shooting.
It’s also important to choose a filter that is compatible with your drone’s camera and lens. I use the Freewell brand for both Mavic Air 2 and DJI FPV and they seem to do the trick just fine.
I do believe that ND filters are an essential accessory for anyone looking to capture professional-looking aerial footage and amazing photos with their drone.
Thank you for taking the time to read this, I hope it’s been helpful to you 🙂