This post was last modified: 2013-09-27, 00:27 by jaybee.

Hi Gunther,

Hoping you can lend a hand with this problem, it's been driving me nuts all day!

I am getting really annoying (non-camera) flicker on a 600 frame holy grail sequence. The first part is perfect, great transitions on my first few exposure jumps (.1 EV each time). The problems start when the sky starts to go dark blue, just after the golden contrail disappears with the sunset - around the 8 second mark. In addition, there is a jump up in exposure just after all the flickering – I can't explain this either as I've spent a lot of effort making sure my LR star adjustments are continually going down in exposure along with the natural decline in light.

Here's what I've tried, to no avail;

1) Processed all jumps manually using my copy of LRT 2.3.2
2) Tried above with no reference frame set (thought that may be causing the issues).
3) Tried the sequence (200 frames shorter) with the LRT3 evaluation app using the new HG process… the resulting flicker is identical to my manual work.
4) Tried using the deflicker option with no positive effect.

I've double checked all my tediously produced work in LR and all the ** and *** frames are as exact as possible, especially around the darker blue sky where all the problems are.

Any ideas what could be causing this flicker or what I could do the alleviate it?

Please let me know if I can provide any other info to help. Cheers.

https://vimeo.com/75517069
Password: pendragon

LRT2 Screenshot: https://dl.dropboxusercontent.com/u/5837...Screen.png
LRT3 Screenshot: https://dl.dropboxusercontent.com/u/5837...Screen.png

btw. Nice work on LRT3, the new grail system seems to work as good as I could do manually, but saves a ton of time. Very clever stuff. Will most definitely be upgrading soon.

Hi, you should avoid combining deflicker with the Holy Grail technique. In the last step try to match your keyframes as closely as possible in Lightroom (even after the Auto-Holy Grail this might be necessary for fine tuning) - then apply the auto transition special for the hily grail keyframes (2*/3*) again, to smooth out the exposure transition. Now export the video via LRTExporter Plugin. If you still experience "flicker" -> this might not be real flicker - you can try to load the LRT_* intermediate JPG sequence that the exporter produced into LRTimelapse and only apply deflicker to that one. Then export/render again. Might get you closer.
All in all, for Holy Grail sequences it's crucial to do the shooting right without caamera flicker, then the rest is editing.
Best
Gunther

Hi, you should avoid combining deflicker with the Holy Grail technique. In the last step try to match your keyframes as closely as possible in Lightroom (even after the Auto-Holy Grail this might be necessary for fine tuning) - then apply the auto transition special for the hily grail keyframes (2*/3*) again, to smooth out the exposure transition. Now export the video via LRTExporter Plugin. If you still experience "flicker" -> this might not be real flicker - you can try to load the LRT_* intermediate JPG sequence that the exporter produced into LRTimelapse and only apply deflicker to that one. Then export/render again. Might get you closer.
All in all, for Holy Grail sequences it's crucial to do the shooting right without caamera flicker, then the rest is editing.
Best
Gunther

Thanks for getting back to me. The flickering wasn't from camera flicker but I think somehow created when LRT interpolated between the darker sky HG frames. Ive attached an image of the HG keyframes in LR, as I mentioned above – I'd fastidiously adjusted them so they were perfect. The first 8 secs of the scene when the sky is lighter etc. are immaculate, the EV changes were the same 0.1 each time.

In the end, I managed to clean things up by using the LRT graduated filter in LR to reduce the exposure on the darker sky section (helped a lot with the weird jump up) and by using GBDeflicker in AE. That worked pretty well, the sequence looks much less distracting now. An agonising process for a single sequence... but hey, no one ever said this business would be a walk in the park ; )

https://dl.dropboxusercontent.com/u/5837...Screen.png

Hi Jaybee,
Are you sure your EV-jumps were 0.1? Sound like a lot.

I have experienced something similar when I pushed the ISO too high (that kind of flicker in your video doesn't look like a problem of matching key frames to me).

At least my camera produces clearly worse results with high ISO and long time exposure (several seconds) compared to high ISO and short time exposure (far below 1 second). So i have to keep the ISO low when shooting in the night, results are fine.

Hi Jaybee,
Are you sure your EV-jumps were 0.1? Sound like a lot.

I have experienced something similar when I pushed the ISO too high (that kind of flicker in your video doesn't look like a problem of matching key frames to me).

At least my camera produces clearly worse results with high ISO and long time exposure (several seconds) compared to high ISO and short time exposure (far below 1 second). So i have to keep the ISO low when shooting in the night, results are fine.

With the EV I meant one sub-division of a stop each time, i.e, the smallest step. The ISO was 100 throughout.

In the scene, the sky gets darker and each HG step I adjusted gradually gets darker (look at this image https://dl.dropboxusercontent.com/u/5837...Screen.png) so there shouldn't be any flicker as all the EV jumps are smoothed out.