LRTimelapse Forum

Hi everyone,

Here is a photo of an LRTimelapse2 session I ran recently, trying to rescue one of the earliest time lapse shoots I did, when I didn't know anything about aperture flicker. You can see how horrible the curve looks near the end of the first section - this is because I was switching to the smallest apertures of my lens - f/20, f/22 etc.

I have tried to deflicker this sequence, but the best LRTimelapse can do seems to be to replace the flickery section with a curve that has a couple of smooth parts to it, but which doesn't really match what should be there - i.e. I want the target brightness to be a smooth curve that runs along the top of what we can see in this image, but LRTimelapse takes into account all the darker frames and does something different. Adjusting the sliders doesn't improve the situation much.

I know that the small aperture is to blame and perhaps I cannot rescue this sequence, but I have two questions:

1. Would this be a situation in which the two-pass deflickering method could help?

2. Is it worth deflickering this anyway? I think perhaps the exposures are varying so much, that even if I were to be able to get them to follow a smooth curve, there might still be flicker due to the differences in tone that might be present due to the different brightness levels.

Thanks for any help anyone can offer with this salvage project

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Hi, I'm not seeing any reference area set in that "screenshot" - I don't know what causes the big downward peaks in the sequence. Is this really flicker? You shoud try to define a reference area to separate the flicker from the other effects. Then you might get better results that you could even improve with the 2-step method.
However there is no guarantee that you can fully recover a totally blown sequence but it's worth a try.

(2013-06-13, 17:35)gwegner Wrote: [ -> ]Hi, I'm not seeing any reference area set in that "screenshot" - I don't know what causes the big downward peaks in the sequence. Is this really flicker? You shoud try to define a reference area to separate the flicker from the other effects. Then you might get better results that you could even improve with the 2-step method.
However there is no guarantee that you can fully recover a totally blown sequence but it's worth a try.

Thank you for the help Gunther.! I actually just didn't take enough photos of the screen - later on I did define a reference area, and it was after that when I had the trouble with the deflickering. I will try to run this again later tonight and post a better image. Sorry about that!

OK, here are some screen shots that I just made.

The first one shows the big variations - looking at the table now, I notice that these all happened at f/20, but at f/22 everything was fine. I am wondering whether my lens has a problem with that one stop for some reason - maybe bad contacts on the day?

[attachment=359]

Anyway, here is the second screen shot, which shows how LRTimelapse tries to deflicker. It would be very cool if there were some way I could over-ride its decision and draw my own curve - then I would of course just draw it along the top of the jagged blue line, where the brightness would almost certainly be if the camera had not let me down...

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You should at least get rid of the first set of holy grail key frames, there is no big change (it think it's where you changed from f/22 to f/20 - but I don't think you will get perfect results on that sequences because you really messed it up when shooting, sorry...
The first thing is I would shoot those sequences wide open to avoid th flickering. There is no foreground that would justify stepping down. Then adjust the Shuttertime and ISO for Holy grail, never the Aperture. I explained all of these techniques in my Ebook.

(2013-06-14, 13:47)gwegner Wrote: [ -> ]You should at least get rid of the first set of holy grail key frames, there is no big change (it think it's where you changed from f/22 to f/20 - but I don't think you will get perfect results on that sequences because you really messed it up when shooting, sorry...
The first thing is I would shoot those sequences wide open to avoid th flickering. There is no foreground that would justify stepping down. Then adjust the Shuttertime and ISO for Holy grail, never the Aperture. I explained all of these techniques in my Ebook.

You're right - I think that first set of HG keyframes does look unnecessary - although I think they are on a transition that is not visible in the table in the screen shot. But I will definitely check that out, thanks! Maybe it will give me something usable - or perhaps I can fudge it by adjusting just the screwed-up portion's exposure values manually in Lightroom before rendering the video - it would take a little while but could work...

Thanks for the help Gunther, much appreciated, and of course I have read your book now and I would never shoot a sequence that way again