Testing my GoPro HD Hero 2’s capabilities drew a response on YouTube for an article on cleaning up low-light time-lapse noise.

Collapse Controversial? YouTube

Low Light Time-lapse Processing in After Effects

Back in 2012 I bought a new GoPro HD Hero 2 for an upcoming snowboarding holiday. Before going I wanted to get an idea of the camera’s capabilities and went about a few processes, one being a low light time-lapse.

A comment later and I’m writing this, albeit a bit late but I’m working on my snowboarding video so please forgive me! I’m assuming some basic knowledge of AE, please leave a comment if you think I’ve missed something vital.

How to time-lapse in After Effects

Simply take your time-lapse imagery into AE (CTRL + I) selecting the first frame of the lapse and importing as footage (there should be a ticked option for JPEG sequence). The HD Hero 2 will store a single lapse across multiple folders if it’s long enough so you have two options, either is fine:

  • Put everything in one folder
  • Add them together in AE

Once it’s in your composition (I used a default 720p 25fps comp) and you’re happy with the scale etc the first thing I did was modify the speed of the lapse. This is because I shot loads of images and it was taking too long for anything to happen. So, right click on the resource in the project panel and select interpret footage > main. In here, modify the frame rate to more than 25, I went for 99.. because I’m impatient.

How to remove the noise

Now you’ve got your time-lapse in your comp and you’ve taken a look by doing a pre-render (insert/0 key) you’ve noticed that when the light drops out things get very noisy. The camera is good, but it’s not that good, it prefers to live in bright light (like a snowy mountain side at midday, not like below).

So you want to add some noise reduction. I created an adjustment layer above the footage and applied the filter “remove grain”. I also used curves and levels to adjust the lighting slightly. It’s at this point I can’t tell you what to do because it depends on your footage, the key is to test!

OK so what did I do? The full settings for “remove grain” are in the image below, but critically (for my lapse) I keyed the unsharp mask amount. This gave me precise control over the detail retention (like the tree edges). I originally tried to make my own mask, but with the trees it’s difficult to achieve something blended nicely. Because your time-lapse probably has quickly varying light conditions keying the unsharp mask, or even the amount of noise reduction, is useful to match with the variable amount of noise in the lapse.

So that’s pretty much it. Getting the light levels as you want them, removing just the right amount of noise is all subjective. Too much and you’ll blur the image. Below is a cleaner frame from the video.

Hope someone finds this useful, especially the chap who posted on my video. Thanks for reading.

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