1
\$\begingroup\$

I have a Sony A7C with the basic Sony FE 28-60mm F4-5.6 lens, and I went to one of the 3 best places in the world to see the night sky. I tried to shoot a night sky hyperlapse using the interval shooting function. I set the camera mode to Manual, with manual focus, 4000 ISO, f/4, 28mm focal length and 4 seconds of shutter speed.

Since it was my first time trying this mode, I didn't expect one of the worst enemies of hyperlapses: flickering. I then started researching how to deal with this in post-processing and I tried using the trial version of LRTimelapse.

The workflow I used is as follows: I imported the sequence to LRT and computed a first visual preview, then saved metadata, switched to Lightroom to read the metadata and started with colour-correcting the first image as the keyframe to apply it to all the images. I used the following settings for the post-production:

enter image description here enter image description here

I then switched back to LRT, reloaded the metadata from Lightroom and computed the visual preview again to see the amount of flickering. I then started to deflicker setting 30 as smoothing, high precision and a multi-pass deflicker of 3. Since the initial flickering was abnormal, as shown by the red curve in the following image. I had to improve the deflicker 3 times to kill all the flickering according to the magenta curve:

enter image description here

Now, in this image, I also tried to select a subset of the photo, but the final result is the same as when I didn't use any subset, and the flickering is so high that the clip is unusable, as shown in this video, despite the curve is flat according to the smoothness. I also saw that not only my clip was suffering from exposure flickering, but also all the frames have visibly different colour tones.

Preview video from LRTimelapse

I researched then why this was happening and on the internet, I found who was blaming the dehaze function, and who was blaming highlights and shadows, but none of the attempts worked to minimise this problem. Also, the flickering was already visible from the raw images, but as far as I searched, the Sony A7C doesn't have an inbuilt deflicker.

Can someone suggest to me what I may have done wrong either in the shooting session or in post-processing?

\$\endgroup\$

1 Answer 1

0
\$\begingroup\$

If auto white balance was used that can/will cause a shift in color between images; and that can affect the exposure as well. But that should be easy to identify and rectify in the raw files (tempt/tint settings).

Long exposure noise reduction could also be having an affect; it does apply to raw files as well, but I would expect it to be much more subtle

I don't see any other setting that would/should affect the raw files. Have you tried the TimeLapse DeFlicker program? It has a free trial version you could test on the problematic scene.

\$\endgroup\$
1
  • \$\begingroup\$ I forgot to specify a couple of things, my fault. The white balance was set to "warm white" (3200K-3700K) and I shot in 12-bit raw files. I should try different and minimal settings to see which one could increase or decrease the flicker. I'll give a look to the software you mentioned, thanks! \$\endgroup\$
    – NorthSon
    Commented Apr 2 at 22:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.