Why Automatic Exposure Settings for your Drone is a Bad Idea.

Updated: Mar 9


Automatic Exposure Settings


Overview


If you are using your drone for any kind of photography, whether it is filming a smooth promotional video or doing technical mapping or inspection related work, you have probably come across drone exposure settings. After all, the drone is nothing but a camera sensor flying in 3D space, and understanding the core concept of exposure is key to collecting high quality data.


So what exactly are these exposure setting and why is 'auto' exposure mode such a bad idea?

We will have a look in this post below.


What are Exposure Settings?


Exposure settings of a camera, as the name implies, control the camera's overall exposure to light. Generally speaking, on a dull day, you would want more exposure (more light entering the drone's camera) and on a bright day, you would want to limit this exposure.

Exposure Settings typically include:

  • Shutter Speed - The speed at which the camera opens and closes its shutter

  • Aperture - The size of the camera hole allowing light in.

  • ISO - Your camera's overall sensitivity to light.

  • White Balance - The amount of colour balance in the images.


Exposure Settings

Why do exposure settings matter?


As we mentioned above, exposure settings control the total amount of light entering the drone's camera. This is important for drone flights as you do not want your images to be under-exposed or over-exposed during flight.


For drone flights, what's particularly important, is that the camera should maintain a constant exposure throughout the duration of the flight so that all images maintain the same exposure level, and can be easily analyzed during the post processing stage.


But how do we maintain a well-balanced and constant exposure?

We will explore this in the next section.


What does Auto exposure mode do?


It's common for commercial off-the-shelf drones like the DJI Mavic 2 series to have an

'automatic' exposure mode built in.


The automatic exposure mode, as the name implies, finds the right balance between the different exposure modes to prevent images that are under or over exposed. Sound pretty good, right? Not quite we are afraid.


Why is this mode such a bad idea?


Whilst the automatic exposure mode is great for discovering the optimal exposure parameters prior to flight, it is not so great at maintaining those parameters throughout the duration of the flight.


A change in ambient lighting conditions during drone flights is very likely - your drone might suddenly be capturing an area that is dimly lit or has shadows all over it. You might also experience a sudden cloud cover on a sunny day, again drastically changing the lighting conditions of your flying environment.


All of the above means that your 'automatic' exposure settings can adjust your camera's exposure during flight and therefore extremely inconsistent looking images. If your goal is to collect high quality data, this is highly destructive and leads to repeat site visits and flying, which of course is a no-no.



Automatic Exposure Settings

What Exposure Mode to use instead?


What's worse is that using 'automatic' exposure settings can alter the shutter speed during flight, which has a direct impact on your drone's flying speed. We cover that in more detail in this post.


So the key question is -

If you cannot use automatic exposure settings, then what mode to use instead?

One option is to use 'automatic' exposure mode on the flight day to discover the correct exposure parameters. Then switching over the 'manual' exposure mode and applying the shutter speed, ISO and white balance properties manually. This will ensure that you are using the correct exposure parameters and that they do not change during flight.


Another option is to use a mode like Shutter Priority. This mode ensures that the Shutter Speed is kept constant throughout the flight and other parameters such as Aperture or ISO are adjusted by the drone's camera to achieve a good exposure level.


How to set these modes?


Exposure Modes, whilst tricky to understand at first, can be a great way for you to ensure high quality data collection. You should be able to set this up in the mission planning app that you use to plan missions for your drone.


In Hammer Missions, these settings can be adjusted by simply switching to the video view. Hammer also gives you the flexibility to save exposure settings for repeat use or to use exposure settings setup up in DJI Go.


Hammer Missions Exposure Settings

Summary


In this guide we looked at how to setup exposure settings for your drone.

If you'd like to learn more about how to high quality data and the get the most out of your drone missions, please feel free to visit our learning resources.


If you haven't got a Hammer account as yet, and would like try Hammer Missions you can get started on our free trial.


To learn more about our enterprise solutions, including mission collaboration, data processing and AI solutions, please contact us at team@hammermissions.com.


We look forward to hearing from you.


- The Hammer Team

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