Author Topic: Auto ETTR based on RAW histogram (ettr.mo)  (Read 95887 times)

a1ex

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #175 on: August 01, 2017, 12:40:54 AM »
I have some problem, when I using ETTR with 1/2 stop for shooting timelapse and postprocess it with LRTimelapse. LRTimelapse can work only with step 1/3 stop. Can I change some settings ETTR for change step from 1/2 to 1/3?

You'll have to change the code, and it's not trivial. You'll need to disallow 1/2-stop exposures and account for the rounding used in 1/3-stop mode (actually 3/8 and 5/8).

To my knowledge, LRTimelapse is a commercial program, so you might have better luck with feature requests there.

That said, we have our own deflickering tools that do not use the EXIF info at all. Some examples:
- Deflicker module (original version, not very practical, as deflickering is best done in post)
- Bridge script (similar algorithm, but requires proprietary software)
- mlvfs --deflicker and mlv_dump --deflicker (for MLV timelapse, e.g. silent pics or raw video)

The same deflickering algorithm is available in Darktable.

Psih

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #176 on: July 06, 2018, 12:32:32 PM »
The smaller the steps, the better the results - therefore I need this option and I am ready to pay for this option. Can somebody do it?

Audionut

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #177 on: July 06, 2018, 01:58:21 PM »
The smaller the steps, the better the results

Proof.  Use images, we already understand the science.

Psih

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #178 on: July 06, 2018, 02:12:06 PM »
I'm getting better results, when I stop shoot with ETTR and start use qDSLRdashboard. The transition between day and night is more smooth. I can't provide any proof, only my experience on shooting timelapse. I'm regularly shoot timelapses and I want this option and I can pay. If it is impossible, I will search another way (timelapse+ for example).
I'm sorry for double post.

Audionut

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #179 on: July 06, 2018, 02:17:40 PM »
The transition between day and night is more smooth.

Post processing issue.  The following may help.

That said, we have our own deflickering tools that do not use the EXIF info at all. Some examples:
- Deflicker module (original version, not very practical, as deflickering is best done in post)
- Bridge script (similar algorithm, but requires proprietary software)
- mlvfs --deflicker and mlv_dump --deflicker (for MLV timelapse, e.g. silent pics or raw video)

The same deflickering algorithm is available in Darktable.

Psih

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #180 on: July 06, 2018, 03:05:36 PM »
Post processing the same in both case (ETTR and qDSLRdashboard) and I don't think that problem is in one. I think, if this feature is so difficult, I can find another way. Timelapse+ cost 400$. If nobody can't solve this problem, this is sad, but I will buy Timelapse+.

Audionut

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #181 on: July 06, 2018, 03:49:51 PM »
If you're not willing to spend time solving the post processing issue, part with your $400.  That choice is entirely yours.

Exposure matching is exposure matching.  Doesn't matter how different the images are, whether those images are captured with 1/3 stop or 1/2 stop exposure settings (exposure is changing during day > night even with exact same camera exposure settings), there is an exposure difference, and this exposure difference needs to be calculated.

If the post processing software is struggling with the difference between camera exposure settings (1/3 vs 1/2 stop), then the issue lies within the post processing software.

Having narrower exposure differences is always better (from a pure quality standpoint).  Mostly for pixel peeping, but credit where it's due.  However, and to answer your other question.

You'll have to change the code, and it's not trivial. You'll need to disallow 1/2-stop exposures and account for the rounding used in 1/3-stop mode (actually 3/8 and 5/8).

I would advise leaving the comfortable box, trying other post processing software, before parting with $400, but it's your $'s and your decision.  Personally I've had good results with the bridge script, but I was only playing, nothing serious, and I've not used the mlvfs or mlv_dump options.

For me, the end goal is not to provide a finished product that everybody can consume. I'd rather see it as an open software platform where others can program their own enhancements and share them with the community

This is a development based community, where we contribute with skills and knowledge, not monetary offers.

a1ex

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #182 on: July 06, 2018, 06:45:53 PM »
Just FYI - an older example with the deflicker algorithm used in the tools mentioned earlier:


Don't know whether the transition is smooth enough for your needs or not, but I'm pretty sure that using 1/3 stops instead of 1/2 won't make any noticeable difference. You may notice exposure jumps much larger than 1/2 EV in the input video (the one displayed in smaller size).

c_joerg

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Re: Auto ETTR based on RAW histogram (ettr.mo)
« Reply #183 on: July 09, 2018, 01:56:15 PM »
Exposure matching is exposure matching.  Doesn't matter how different the images are, whether those images are captured with 1/3 stop or 1/2 stop exposure settings

Just for understanding.
This video is made with 1/3 stops end I can’t correct the pumping sun in post because the core of the sun is blown out.
If I were to create these recordings with ETTR then you could probably correct it but then I would lose a lot of information especially in the dark areas.

I really like the CHDK part where I can change exposure in 1/96 stops…
6D