So what is an ND filter? Simply speaking, ND filter is the perfect drone camera lens filter if you wish to capture cinematic-looking footage of objects in motion, especially during bright sunny conditions outdoor.
The features, types, and functions of drone camera filters, especially the ND (Neutral Density) filters are most efficiently explained on the popular Danish YouTube channel – Drones and Electric Unicycles. With over 15,000 subscribers tuning in to learn more about drone flying and accessories, it is one of the top expert channels for drone lovers.
Even though ND filters have been around for a significant time now, there are still large numbers of amateur aerial photographers and even some professional aerial cinematographers who have some confusion about what ND filters are, what they do, and when and where to use them. Today, there are several types of ND filters available, such as Polarized (Hybrid), Gradual, Variable, etc. so it’s kind of obvious why their use and purpose may get confusing from time to time.
Well, don’t worry anymore. In this under-20 minutes read, you will learn the fundamentals of ND filters and all you need to know about choosing the right ND filter at the right time.
What is an ND Filter?
An ND (Neutral Density) filter is designed to allow a certain amount of light to enter the camera lens. Typically, a generic ND filter will not have any effect or improvement in your footage quality or colors.
Conventionally, ND filters are denoted according to numbers – such as ND4, ND8, ND16, ND32, ND64, ND1000 and ND2000.
To understand the function of an ND filter, all you need to know is that, the higher the number on the ND filter the darker will be your footage, thanks to its ability to block certain amount of light, depending on the numbers.
Why will you need ND Filters?
As mentioned earlier, ND filters are responsible for adding that typical ‘naturally blurry motion’, we see in cinematic footage. This is an inherent way of making the footage seem alive and more pleasant to look at. The basic reason for this is how the naked eye perceives objects in motion – partially blurry as they move across your line of sight.
The smooth and naturally blurry objects you capture in your footage make it more appealing.
Remember the ‘180˚ Rule’, which theorizes that the shutter speed should be reduced to the double that of the frame rate. Shutter speed simply means the amount of time the camera sensor within the lens is exposed to the incoming light.
Example – If your frame speed is set at 30 fps, then your shutter speed should be set at about 1/60th (or 60).
When will you need ND Filters?
An ND filter is more effective when you wish to capture perfect motion blur in your footage, when shooting outdoors, in bright sunlight conditions. Although you can set the aperture in a DSLR camera, this is not always possible in the drone. Hence, fitting the drone camera lens with an ND filter allows you to control the brightness of the view, and ensure sharper pictures.
An ND filter to capture motion blur is most effective when the objects in motion are close by, or when the drone is being flown at a lower altitude.
When will you need Polarized ND Filters?
The Polarized ND filter is effective in removing unwanted reflections from surfaces outdoors, besides helping to darken the brightness of the sky.
The Polarized ND filter is also able to improve color of the greenery you capture, by balancing the saturation and preventing unwanted brightness from spoiling the crystal-clear picture quality. In general, the polarized ND filter is an excellent way to add artistic effects to your footage.
When will you need Hybrid ND/PL Filters?
A hybrid filter, also known as ND/PL filter, combines the functions of the Neutral Density filters and the polarizing lens filters into one single drone filter.
Essentially, you can rotate the ring on the filter to set the amount of light allowed into the camera lens, and control the shutter speed accordingly.
How to use ND Filter with DJI Mavic Air?
There are several brands that offer ND and Polarizing ND filters today. However, the DJI Mavic Air ND Filter All Day 8 Pack from Freewell Gear is one of the top choices of our experts and thousands of professional aerial photographers and cinematographers from all over the world.
Steps to Install ND filters on DJI Mavic Air
Thanks to the efficient SCREW-ON system of the Freewell ND filters, it is easiest to fit the ND filter on your DJI Mavic Air camera.
Follow these simple steps and learn how to install your Freewell Gear ND filter on your Mavic Air drone:
Flip over the DJI Mavic Air on its back. Hold the gimbal firmly with one hand while gently unscrewing the thread protector (ring) which is pre-installed on the Mavic Air’s camera.
After you have safely removed the thread protector ring, take the ND filter from Freewell and install it by screwing it on the camera’s lens thread. As the design of the Freewell ND filters are perfect fit for the DJI Mavic Air camera, you won’t require using excessive force to tighten the filter in place.
These 2 steps make it one of the easiest installation processes for drone camera filters. Apart from performing its core functions, the ND filter is so lightweight that it does not have any adverse effect on the gimbal. Not only this, the ND filter can be kept on at all times, even when the drone is not in use, as this acts to protect the fragile camera lens too.
How will you choose the right ND Filter?
First off, it is important to remember that the core purpose of using ND filters is to actually create a motion blur while capturing your footage.
Camera Settings before Installing ND Filters
To get optimum results from using ND filters, there are certain alterations to the camera setting that you will need to do, such as:
Step 1 – Switch the main camera setting to the ‘MANUAL’ mode.
Step 2 – Set the Video Settings to capture 1080p footage at 25 fps.
Step 3 – Adjust the shutter speed to twice that of the frame rate, i.e. – 25 fps = 50 shutter speed.
Step 4 – Adjust the ISO to the lowest (100).
*Always remember to change the shutter speed whenever you change the frame rate.*
Step 5 – Change the Color profile to ‘D-Cinelike’.
Step 6 – Adjust the White Balance according to the scene and conditions of shoot.
Step 7 – Adjust the Style settings to (0, 0, 0)
Now that you know the camera settings which help to capture cinematic shots, let’s look at the type of ND filter you will need to select at what time.
Choosing the Right ND Filter
Once you have taken care of the main camera settings, it is time to prepare for fitting the appropriate filter.
Step 1 – Go to Camera Settings and enable the Histogram and Over Exposure Warning options. This will transform your view into ‘tiger-stripes’.
This is an excellent way to check the exposure level of your pictures.
Step 2 – Choose the filter from the Freewell Gear Day Pack which suits the present weather/lighting conditions (such as Cloudy Days, Partly Cloudy Days, Sunny Days, Reducing Glare, Partly Cloudy Day & Reducing Glare, Bright Sunny Days & Reducing Glare, and Very Bright Sunny Days & Reducing Glare).
Once you have fitted what you think is the correct filter, according to the guidelines on the filter pack, switch on the drone and check the picture quality on the viewing monitor. If the view is darker than you desire, switch to the ND filter with a lower number than the current one. Vice versa, in case the scene seems too bright after fitting an ND filter, then you can simply switch the filter with a higher numbered ND filter from the pack.
It is important to ensure that the ‘EV’ value is between 0 to -0.7, as this helps to get the best exposure.
Well, here’s all you need to know to get started with your Freewell Gear Mavic Air ND filters. Use the Freewell ND filter to ensure optimum-quality footage and images, which present a cinematic and breathtaking show.