Know More About ND Filters

An ND (Neutral Density) filter is a gray-tinted filter, similar to sunglasses, used to control the amount of light entering the lens. It reduces the intensity of light uniformly across all wavelengths without affecting the color balance of the image. ND filters are typically mounted in front of the camera lens. 

Before diving into the specific settings to use on your X1 PRO &PROMAX, it’s helpful to understand the basics of photography if you’re new to the subject. Three factors control the exposure of an image:

1. Aperture
2. ISO
3. Shutter speed

Aperture controls how much light reaches the image sensor. As you open the aperture, more light enters, making the image brighter. However, the aperture on the HOVERAir X1 PRO & PROMAX is fixed, though you can adjust the exposure compensation to control brightness. 

ISO refers to the digital gain applied to the brightness of an image. However, it’s the last setting we want to adjust, as increasing ISO also makes the image noisier. 

Shutter speed (also known as exposure time) refers to the length of time the shutter is open, allowing light to enter the camera and reach the image sensor. Shutter speed is displayed in values such as 1 second, 1/2 second, 1/4 second... up to 1/125 second or 1/250 second. A faster shutter speed shortens the time that light enters the camera, while a slower shutter speed extends this duration. Therefore, the slower the shutter speed, the more light can enter the camera. 

Additionally, when setting the shutter speed, you need to follow the commonly used 180° rule.

The 180-degree rule is simple: set the shutter speed to one over twice the frame rate. For example, for 30 fps, use 1/60; for 60 fps, use 1/120. This creates a 180-degree shutter angle, resulting in natural motion blur. If you want more, you can go up to a 360-degree angle (e.g., 1/30 at 30 fps), but be aware this may add excessive blur. Experiment with angles between 180 and 360 degrees to find what works best. This principle also applies to high-frame-rate shots; at 240 fps, for instance, set the shutter speed to 1/480 for similar blur. 

For the HOVERAir X1 PRO and PROMAX, feel free to adjust based on your preferences and shooting conditions. 

Note:  EV(Exposure compensation), ISO, and shutter speed on the HOVERAir X1 PRO & PROMAX can only be adjusted in manual mode and are not adjustable in intelligent modes.

1. Reduce Light Intensity : In very bright environments, like direct sunlight, using an ND filter prevents overexposure.
2. Extend Exposure Time : ND filters allow you to use slower shutter speeds during the day, enabling you to capture effects like silky-smooth water or light trails from cars.
3. Use Wide Aperture : In well-lit conditions, ND filters let you shoot with a wide aperture to achieve a shallow depth of field without worrying about overexposure.
4. Capture Motion Blur : When shooting dynamic scenes, ND filters help you capture the motion blur of moving subjects, adding a sense of movement to your photos.

ND filters come in various levels depending on the degree of light reduction. The HOVERAir X1 PRO and PROMAX have the following filters: ND8, ND16, ND32, and ND64. Other common levels include ND2, ND4, and ND1000. These numbers indicate how much light is reduced. For example:

• ND2: Reduces 1 stop of light, cutting the light intensity by half.
• ND4: Reduces 2 stops of light, cutting the light to 1/4 of the original intensity.
• ND8: Reduces 3 stops of light, cutting the light to 1/8 of the original intensity.
• ND16: Reduces 4 stops of light, cutting the light to 1/16 of the original intensity.
• ND32: Reduces 5 stops of light, cutting the light to 1/32 of the original intensity.
• ND64: Reduces 6 stops of light, cutting the light to 1/64 of the original intensity.

This grading system allows photographers to choose the right ND filter based on their shooting needs. Here are the parameters for each level of ND filter:

Know more：https://en.wikipedia.org/wiki/Neutral-density_filter

The ND filter pack from HOVERAir comes in a sleek case and includes four filters (ND8, ND16, ND32, and ND64). The camera has a small removable frame, and the ND filters securely slide into place.

This first time taking the frame off might feel a bit difficult, but this is how we've found it to be the easiest to use:

• Step 1 - turn the drone upside down with the camera facing you;
• Step 2 - firmly hold the gimbal with both hands;
• Step 3 - while holding the gimbal, push with your thumbs up on the bottom corners of the frame (you can do one corner and then the other) until it unclips;
• Step 4 - slide the frame off and slide in the desired ND filter.
• Step 5 - Open the "ND Filter Optimization" option in the HOVER X1 App>Hover Setting. Image processing is optimized based on this setting, and if it’s not enabled, the image quality may be poor.

Note, that after the first few uses it will slide in and out more easily. 

Your choice of ND filter depends heavily on the environment, and lighting conditions, and the effect you'd like. Here are some recommendations:

• For optimal motion blur, use the ND64 filter in bright beach and sunny conditions, the ND16 or ND32 filters in intense midday sunlight, and the ND8 filter in lighting within an hour after sunrise or an hour before sunset.
• You can manually set the shutter speed to your desired level, or allow it to adjust automatically. In auto mode, the drone will first prioritize minimizing noise, then aim to extend the exposure time per frame as much as possible.
• It’s important to actually check your image exposure (preview) before shooting to avoid surprises.

With practice, you’ll get a feeling for choosing the right ND filters and camera settings to capture the footage you want. Experimenting with different filters in various lighting conditions will help you refine your skills and achieve the effects you’re after. What are some of your favorite techniques for using ND filters? Let us know if you have any questions or need more tips—we’re here to help!