Best exposure for BRAW?

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Dennis Sørensen

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Best exposure for BRAW?

PostFri Sep 13, 2019 2:31 pm

Hi guys.

I am a ProRes shooter for long, but would like to start shooting BRAW. I am used to shooting at native ISO and adjust my exposure with NDs or the aperture. I know how to expose and I rarely have to adjust anything over 1+ stop in post (and that is only if the meters have been lying to me).

With raw we gain the ability to recover highlights. So is it better to overexpose, bring it down in post and use highlight recovery to maximise DR?

I tried a test where one of the clips I exposed correctly and then another where I overexposed a bit, brought it down in post and used highlight recovery. It seemed to have more information in the scopes.

Is highlight recovery only for disaster situations where one would recover the highlights because of user error, or is this a proper technique to maximise information?

I will be honest, I have not given braw that much practical attention since it came out. But as they now support Premiere Pro and AVID I will have a go at it and update my P4K so that it no longer shoots CinemaDNG and gets BRAW.

Feel free to point me in any direction where this has already been discussed. As I know I am a bit of a late adopter.
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John Paines

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 2:36 pm

Highlight recovery will only work if there is still information in one or more of the color channels. So no, it's not an exposure technique. I think it's better viewed as an emergency recovery measure. You'll note also that results will vary.

I would approach braw the same way you do Prores.
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John Brawley

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 2:47 pm

I think it’s better to still middle the exposure like you do for ProRes.

The highlight recovery is only designed to reconstruct some colour information in some colour channels when you have clipping in one channel and not the other.

In reality the “recovery” possible is actually more like fixing a weird colour tint in near clipping. NOT recovering information.

This is not like in PS when you loaded a DNG and it magically seemed to pull in extra highlights that had gone.

Now with BRAW you start off with pretty much all the information from the beginning.

JB
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Dennis Sørensen

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 2:56 pm

John Paines wrote:Highlight recovery will only work if there is still information in one or more of the color channels. So no, it's not an exposure technique. I think it's better viewed as an emergency recovery measure. You'll note also that results will vary.

I would approach braw the same way you do Prores.


John Brawley wrote:I think it’s better to still middle the exposure like you do for ProRes.

The highlight recovery is only designed to reconstruct some colour information in some colour channels when you have clipping in one channel and not the other.

In reality the “recovery” possible is actually more like fixing a weird colour tint in near clipping. NOT recovering information.

This is not like in PS when you loaded a DNG and it magically seemed to pull in extra highlights that had gone.

Now with BRAW you start off with pretty much all the information from the beginning.

JB


Thank you for time and answers! I will continue to expose as I have always been doing since BMCC days.

I know that it only really works if only one channel clipped, but as long as it only clipped one channel doesnt it extend the DR?

Again. Thank you so much for your time!
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JoshMallett

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 4:32 pm

I would never overexpose and say "I'll just fix later in post"...ESPECIALLY with my experience with BRAW.

I've also seen others on this board saying they're surprised highlight recovery isn't as good as it should be (as compared to other RAW formats)..and I concur.

It's easier to have to boost a little bit and most and do a little noise reduction than to have to try and recover blown highlights.
My video work: https://www.JoshuaMallett.com
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Dune00z

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 5:54 pm

For pocket 4k, I do a +1 stop overexposure when I can and do a 1 stop pulldown in post, using the false color tool as a guide for middle gray. You get much cleaner shadows and there is no negative effect to the image unless you completely blew the highlights. Highlight recovery is not a catch all and sometimes causes artifacts so don't rely on it.

I will consistently shoot in this fashion for a scene/segment. If I can't do this, I expose "normally" as JB said.
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carlomacchiavello

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 6:05 pm

Braw mean 12bit vs Prores 10bit, a lots of infos more than prores, but...
If you apply the same rules of exposure, you enjoy better of braw. You can change iso, yes, and WB is not baked on shooting, but not think you can do everything.
The secret is that a good exposure give you excellent picture.


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John Paines

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 6:23 pm

Dune00z wrote:For pocket 4k, I do a +1 stop overexposure when I can and do a 1 stop pulldown in post, using the false color tool as a guide for middle gray


This may be okay for non-dramatic material, like landscapes, but it will put flesh tones, post normalization, at 65-80%. You can bring the levels down and the shots will survive, but the question is whether over-exposing faces in this way is a good practice.
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Oyvind Fiksdal

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 6:50 pm

my finding on the P4K is to handle it more like a Nikon camera rather than canon. 0EV or -1EV. More like ETTL rather than the common ETTR (+EV). Going to far ETTR makes the bright part of the picture harder to balance in post = spending more time in post. Better to try hit it as close as possible to what you want as a finale image. Use a LUT is also a idea to get closer to what you want, combined with false color.
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Dune00z

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 7:35 pm

John Paines wrote:
Dune00z wrote:For pocket 4k, I do a +1 stop overexposure when I can and do a 1 stop pulldown in post, using the false color tool as a guide for middle gray


This may be okay for non-dramatic material, like landscapes, but it will put flesh tones, post normalization, at 65-80%. You can bring the levels down and the shots will survive, but the question is whether over-exposing faces in this way is a good practice.


I meter at ISO 400 and with a 1 stop pulldown in post I see no apparent issue with skin tones at all. It looks exactly the same as exposing normally. If there is an issue then it is imperceptible to me and anyone who has received products from me. I have done many, many tests shooting "normal" and 1 stop over with a pulldown and skin tones are not effected in my results. The only difference visible is noisier shadows on the normal exposure shot.

I use this primarily on interviews. Shadows are perfectly clean with this technique.

I don't shoot feature films or anything, so clearly that will be the job of the team to figure out the best workflow for them. This technique has yielded much better footage for me so I thought I'd share.
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Brian Millbrook

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Re: Best exposure for BRAW?

PostFri Sep 13, 2019 8:23 pm

I usually expose to the right to help prevent a lot of noise. I make sure that I can see the end of the histogram peak so that I don't lose information in the highlights though. Might not be a perfect way to expose, but it's always worked for me on getting super clean images out of Blackmagic cameras. I rarely go into the 1250 iso range. I usually max it at 800 iso and just add additional lighting if the histogram information isn't where I want it to be.
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Dennis Sørensen

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Re: Best exposure for BRAW?

PostMon Sep 16, 2019 11:08 am

JoshMallett wrote:I would never overexpose and say "I'll just fix later in post"...ESPECIALLY with my experience with BRAW.

I've also seen others on this board saying they're surprised highlight recovery isn't as good as it should be (as compared to other RAW formats)..and I concur.

It's easier to have to boost a little bit and most and do a little noise reduction than to have to try and recover blown highlights.


Good for you. I dont really understand what that has to do with me? I said overexpose a little bit to maximise DR.. I am not a "Fix it later in post" guy.. I take very much care of my image before I even press record. I would never just press record and _hope_ to recover in post. Why would you assume that of what I wrote?

But I guess thanks for the info about braw not being as artifact free.
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Dmytro Shijan

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Re: Best exposure for BRAW?

PostMon Sep 16, 2019 12:50 pm

For Pocket4k or 6K use native ISO 400. You can always set expose (ISO) and WB in Resolve and recover few stops from shadows as described here viewtopic.php?f=21&t=65149&p=537852#p537852
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