Many years since my last Timelapse so please be patient,
I am planing a day to night shoot near the sea, when I did this in the past I binned the Timelapse because there was too much flicker in the sea movement before the shutter slowed down considerably,
So this time I was considering using ND filters to try and maintain a slower shutter (5 to 10 seconds)

As LRTimelapse uses exif data I presume the big changes in taking off a 5 stop ND filter will mess up the sequence?
Would the best approach be to process these as 2 separate sequences?
If I edit the last image in the first sequence and the first image in the second sequence identically, would these run together without any jump/flicker?

Removing an ND Filter is usually not a good idea, but LRTimelapse is not the issue here. Of course it won't detect the ND change automatically, but in theory you could fix the manual jump in brightness with two adjacent keyframes.

The challenges are more of general nature:

Most likely you will shake your camera and also after removal the next image(S) would be way too bright.

I'd recommend to shoot with an ND that is only as strong as you can finish the sequence.
Also consider doing different shorter clips with different angles, which would also be better for the final video. Also moving away from the waves is a good idea for Timelapse. You might add some slomo close up shots of the waves to the final video,whichbwould look more dramatic and help the story telling.

Thx
The filter is magnetic, I am confident I can easily remove it without moving the camera,
When I remove the filter I would adjust the iso/aperture so the exposure is the same,
If I use an nd64 this would give me 6 stops,
So with the filter on I could get my shutter where I want it (5 to 10 seconds,) then as it gets darker I would change the Iso 4 stops and aperture 2 stops, I would then remove the ND filter and set the ISO and aperture back to the starting points giving me a continuous exposure level,
I would then continue to alter the Iso and aperture as it gets darker, this would give me 12 stops of latitude with a constant exposure length, then if I need to alter the shutter duration it will be at a point where you won’t see the difference.

This post was last modified: 2023-05-19, 13:09 by Gunther.

Yeah, you'd need to do all this during one interval: remove the filter and change the camera settings by the difference that the filter darkened. When editing your best option would be the following: select the second part without filter and go to "Metadata / Define Aperture". Adjust the aperture by 6 stops (in your case) in order to "simulate" the change in Metadata. (If there is not enough room to do so, do it the other way round. Select the first part and change the Aperture of that in the other direction.)

Now you can use the Holy Grail Wizard as usually.
Still you might get effects like Color-Shift and Change in Vignetting where you removed the filter, but technically this would work.