Hi all,

Shot a sunset-into-stars timelapse recently, 1500 images over 4 hours. Shot the whole thing on Manual, usually changing only 1/3rd of a stop at a time... i.e. I believe I did it correctly. I'm currently on LR 4.8.3 and ran the sequence through deflicker a number of times, but there's some crazy stuff going on towards the end.

https://vimeo.com/577783468

You can see a bit of flicker at 0:11, but the stuff I'm concerned about is around 0:34. It's as if the iso response on the camera (a new Nikon Z6ii) fluctuated, because all of a sudden, the graduated filter at the bottom of the frame (bumping exposure and shadows to pull some detail out of the foreground) seems to make the image noisy and grainy. I would rather not have to go through and manually match, as close as possible, the grainy frames to non-grainy frames. Any thoughts? Is this sensor heat or something that I'm not aware of? The camera was shooting consistent 13s exposures, f2.8, iso 800, at a 15s interval.

Thanks in advance,

Alex

That video is not available. But from what you write, it sounds as if you are pushing the sensor to its limits - there is just no more information in those areas. Combined with holy grail you'll get that "pumping" of changing the camera settings. I'd recomend to edit those parts very dark, so that you don't see the artifacts.
Also you might want to watch my Expert Tips video #5: https://lrtimelapse.com/tutorial/expert/
There you'll learn that also Lightroom might be introducing weird artifacts depending on how you edit.

Ah, my apologies, I had the wrong privacy setting on Vimeo, this link should work: https://vimeo.com/577783468/fc58a4386c

It's strange, I wouldn't have thought that iso 800 on that camera was too dark, especially since one of the frames would come out OK, and the very next didn't, with identical settings. Definitely seems like a hardware thing, as if the two adjacent frames weren't actually the same iso. I expected better from a brand-new mirrorless at 800 iso... :-|

Thank you for linking to the Expert Tips video, very helpful! I'll give it all another pass...

This post was last modified: 2021-07-23, 10:51 by Gunther.

The ISO alone is not the point. It's how much you "push" the shadows when developing. There is just not enough dynamic range to brighten up that part. Additionally you certainly experience the Lightroom issues explained in the Expert Tips video, there are correllated with the headlamps flashing up in the dark.
I think the problem here is a combination of a shooting technique that could be improved (especially use a faster lens for such darkness shots or longer exposure times if possible. If you shoot with ISO 800 in the darkness, you should use a f/1.4 lens for good results) and issues when editing. From what I see, it might be possible to get the editing much better, but I fear it won't be perfect with that source material.

Thank you! The Expert tip definitely taught me a few things, I'm gonna try re-processing the sequence. I appreciate the insight.