Maximizing Multirotor Video Quality

by | May 8, 2014 | tips | 0 comments

If you are at all interested in doing aerial videography (and it is a great hobby that I would certainly encourage you to try) your biggest challenge is going to be optimizing the quality of your videos. Maximizing multirotor video quality is synonymous with minimizing the vibrations to which the camera is exposed. So, while there are a few problems to overcome when it comes to maximizing video quality that don’t relate to minimizing vibrations, and we will get to those problems later, much of this page will address techniques for reducing vibrations.

Before we get started, take a look at the video below. You will notice a kind of wobbling distortion effect. This distortion is called a rolling shutter effect, which is commonly referred to as the “jello effect.” This distortion is caused when cameras using CMOS sensors (which includes almost all modern cameras) are exposed to heavy vibrations while filming.

Multirotor Video Rolling Shutter Distortion

This effect, which, if heavy enough can even cause nausea, is by far the biggest problem for videos shot with multirotor-mounted cameras. It is this distortion that we will try to eliminate using the techniques described on this page.

Let’s start by discussing why quadcopters experience vibrations in the first place. The vibrations, as you can probably guess, are caused by the rotation of the props and motors. If you have ever examined a vibration motor, like the kind used in cell phones, video game controllers, bristlebots, and many other devices, you know that they work by spinning an asymmetric weight. This is exactly how vibrations are generated in a quadcopter. If your props are not perfectly balanced, the rotor will cause increasingly violent vibrations as the motor speed increases.

Technique 1: Balance Props

That brings us to the first technique for reducing vibrations in the quadcopter frame and improving the quality of your aerial videos: while building your quadcopter, make sure your props are perfectly balanced. There are many ways to balance props, but the one I like best is one of the simplest, using a prop balancer tool.

prop balancer tool

A prop balance tool can be used to balance multirotor props in order to reduce vibrations.

Technique 2: Vibration-Dampening Mounts

There is some bad news though; no matter how hard you try to completely balance the props, you will never be able to completely eliminate vibrations from the quadcopter. There is always going to vibration caused by turbulence in the air, or friction in the motors, or wind, or a host of other factors that are either outside our control, or that we cannot eliminate without spending large sums of money (for example on extremely precise motors and/or props).

So, this brings us to the second technique for reducing vibrations to improve video quality, using vibration-dampening camera mounts. Vibration-dampening camera mounts are available in a couple of different designs but they generally consist of soft rubber spacers which are mounted between the quadcopter frame the the camera. These soft rubber spacers absorb the vibrations caused by the quadcopter motors before they can be transferred to the camera.

vibration damping material

These are vibration damping pads for mounting cameras and other vibration-sensitive devices.

However, before you jump to loading up your camera with dampening materials, you should be aware that dampening material is not a substitute for properly-balanced rotors. If the vibrations caused by unbalanced rotors is severe enough, using vibration-dampening camera mounts can actually make the rolling shutter effect worse since heavy vibrations can cause a harmonic effect which causes the camera to sway back and forth on the soft rubber mounts.

Technique 3: Use a Higher Frame Rate

If, after working hard to balance your props and using vibration-dampening camera mounts, you are still getting some rolling shutter effect in your videos, you can try using a higher frame rate. Many pilots report that using a higher frame rate helps to reduce the rolling shutter effect in their videos.

There are two different ways to implement this technique. First, you can invest in a high-quality action camera that is capable of shooting 1080p video at 60 frames per second. Unfortunately, there are only a couple cameras on the market that have this capability and all are quite expensive. The most popular action cameras capable of shooting 1080p video at 60fps are the Sony Action Cam, the Drift Ghost-S, and the GoPro Hero3+ Black Edition.

The second method of implementing this technique, which can be done with less expensive cameras, is to sacrifice resolution in order to increase frame rate. Most moderately-priced action cameras on the market today are capable of shooting 60fps as long as the resolution is limited to 720p.