There are many accessories out there for drones these days. One accessory that can make a big difference in the cinematic quality of your footage is an ND filter.
The three main factors affecting image exposure are aperture, shutter speed and ISO. Drones are often used outside with an abundance of light. If this is the case, your ISO would be as low as possible (usually 100). Some drones allow you to close your aperture (letting less light in) but others have a fixed aperture (like the DJI Mavic). This leaves shutter speed as the main exposure factor. On a sunny day, shutter speed may be around 1/1000s (read as one one thousandth of a second). Herein lies the problem. To get a look that we usually think of as cinematic, you’d want your shutter speed to be 1/2x (one over two times) your frame rate. If your frame rate is 24fps, you’d ideally want your shutter speed to be 1/50s. If your shutter speed is closer to 1/1000s any movement in your image will look overly crisp with very little motion blur (think Saving Private Ryan or zombie movies). This is where an ND filter can come into play.
ND stands for Neutral Density and these filters are basically a dark piece of glass that you put in front of your camera lens in order to add another level of exposure control. An ND2 will let half the amount of light into your lens. An ND4 will let in one quarter the amount of light, an ND8 will let in one eighth the amount of light and so on. In our above example with a base shutter speed of 1/1000s, various ND filters will have the following effects on shutter speed.
For this example, an ND16 will give the best result. An ND8 would allow for too little motion blur while and ND32 would allow for too much motion blur. Obviously there is room for personal preference with exposure and shutter speed. This post is based on the standard rules of cinematography which rely on a 24fps frame rate at 1/50s shutter speed.
There are various brands of ND filters for various drones, but Polar Pro are one of our favorites. Here is a link to a three ND package for the DJI Mavic:
With the help of these ND filters, you’ll have cinematic drone footage in no time!