In order to produce meaningful footage with Elios, the pilot must master the use of the camera and lighting system. This is especially true in low light conditions, where camera and lighting settings should be adjusted continuously depending on whether you are inspecting objects up close, or navigating through large spaces.
Don't forget that flying in such condition is not easy so it's highly recommended to practice in a safe room before performing inspections in such environments.
Also note that the image on the tablet will appear darker than the actual recorded HD footage. Adjust the camera such that the image appears approximately one stop too dark on the live feed to avoid over-exposure on the HD video file.
Four different parameters can be set which will affect the image. The effects they have in dark environments will be discussed briefly.
- LED power
- Exposure Time
The LED power setting is the most direct way to brighten up a dark environment. It does, however, have some side effects such as light reflecting more intensely off Elios' cage and nearby objects. Therefore it is impossible to equally expose the foreground and background when using the LED lights. In most cases, as the LED is the easiest way to bring more light to the environment, you must start by increasing the LED power before adjusting other parameters.
The ISO number refers to the sensitivity of the camera sensor. At a 50 ISO, the camera will not be very sensitive to light, which is sometimes used in extremely bright conditions. At 1600 ISO, even the ambient background light will appear to be amplified, which is useful in dark environments. A disadvantage of strong amplification is that it will add 'noise' to the image. This adds a grainy appearance and reduces details.
The Exposure Time refers to the time during which light is detected by the sensor for each frame. The value is expressed in fractions of a second. Long exposure times appear brighter but can also lead to blurry images if the item being filmed moves while the camera sensor 'captures' it. For example, a 1/1000 second exposure will always appear sharp but requires more light. Whereas a 1/33 second exposure might have motion blur over fast-moving objects:
The EV (Exposure Value) represents a combination of Exposure Time and ISO which create a certain image brightness. This can only be adjusted directly in AUTO mode.
- F: Camera in automatic mode – You set the Exposure Value (EV) and the camera plays with the ISO and exposure time to have a good picture. The EV is equivalent to the overall brightness of the image.
- A: Camera in manual Low ISO mode – ISO is set to 50 and you set the exposure time.
- P: Camera in manual High ISO mode – ISO is set to 1600 and you set the exposure time.