Drones and dynamic range

Published: 3/5/2019   Est. 2 minutes to read

Drones are great, but if you're not shooting with a professional rig like the DJI Inspire or the DJI Mavic Pro 2, chances are you're flying around with a glorified cell phone camera pointed at the ground. There's nothing inherantly wrong with that, the image sensors in modern smart phones fantastic. But the small size limits the dynamic range, and the detail, that the camera can capture.

What is dynamic range?

Dynamic range is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of signals, like sound and light. —Wikipedia

Basically it's the range between shadows and highlights. If you have low dynamic range, the shadows are black, the highlights are white, and all detail is lost. If you have high dynamic range, you retain detail in the shadows and the highlights, creating a more realistic image. The dynamic range of image sensors is rapidly improving but, with older cameras(like my Canon 5D Mark II) or the first generation DJI Mavic Pro, the dynamic range leaves a lot to be desired. Enter HDR.

High dynamic range (HDR) is a technique used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques. —Wikipedia

HDR (High dynamic range) has almost become a dirty word in photography circles. Stemming from the low dynamic range of older digital sensors, stacking multiple exposures to bring detail into an image's shadows and highlights became a popular mainstay. This technique can create amazing results, though everyone has seen a poorly-done HDR image at some point.

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HDR examples from Google Images

When I fly my drone, I always set it to take 5 AEB (auto exposure bracketing) shots. The Mavic Pro is steady enough that the modern de-ghosting algorithims are able to align the shots without issue.

Over Memorial Day weekend my wife and I drove down California State Route 25. It's a gorgeous drive, and only added an extra hour on our way back to Los Angeles from the Bay Area. We stopped a few times along the way to take in the scenery, giving me time to launch my drone and grab some shots.

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Five shots from along California State Route 25 that will be merged

Individually, these are nothing special. But after the exposures have been tone-mapped, we get something really cool.

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The final merged shot from California State Route 25

The colors pop, and the image takes on a sense of realism. The sky is blue, the rippling shadows coursing through the grass, the lush green following the weekends unexpected rain. I'll be processing the rest of the images I took throughout the trip, and I look forward to publishing them along the rest of my aerial photography.