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Recovering dynamic range from raw footage

PostPosted: Sun Mar 04, 2018 9:52 am
by Steveggz
Using my BMCC 2.5k I shot RAW footage that was very overexposed. From what I understand RAW video holds a lot of information. No matter what I do in Davinci I can't get a decent picture other than a all white picture with only the very dark parts of the video showing somewhat.

I saw a Youtube video of a extremely over exposed video (almost all white picture) being fixed in post and looking as if it was never overexposed. How is this done? I've played with every setting and it's as if the RAW video doesn't hold any information to bring back in post. Is there a analysis window I can pull up in Davinci to see if the footage has this RAW video information?

I shot using 2.5k RAW film grade and I'm using Davinci 14.3.0.014 studio.

Re: Recovering dynamic range from raw footage

PostPosted: Thu Mar 08, 2018 10:33 am
by Steveggz
Does anyone have experience fixing overexposed raw footage?

Re: Recovering dynamic range from raw footage

PostPosted: Thu Mar 08, 2018 5:11 pm
by Jim Simon
RAW has more flexibility than other formats, but even it has limitations.

Anything hidden behind zebras on the LCD screen when shooting is gone for good. So be sure you're not clipping when you shoot.

Re: Recovering dynamic range from raw footage

PostPosted: Thu Mar 08, 2018 5:44 pm
by Dermot Shane
try setting project to ACEScct,
set the ODT to 709 or what ever matches your monitor
Import the raw,it will be linear,
adjust exposure and contrast to center the the image on the scopes,
use log lift and gain to normilise it

Re: Recovering dynamic range from raw footage

PostPosted: Thu Mar 08, 2018 7:23 pm
by AndreeMarkefors
I think "recover" is a bad word for photo/video data, unless we're talking lost footage from a backup.

If you didn't capture it, you can't recover it.

If you shot raw and your footage looks really bright, it might still be fine and you might be able to adjust "exposure" in post by using normal tools and/or changing the way the footage is interpreted.

There are techniques where you can reconstruct a clipped channel (let's say the Red) if the Green and Blue are still intact by replicating the shape of the waveform from the not clipped channels.

But neither of these things would mean recovering lost/clipped information.

Re: Recovering dynamic range from raw footage

PostPosted: Thu Mar 08, 2018 8:55 pm
by carlomacchiavello
Overexposed mean you have more info than you need, underexposed mean you have less or nothing info to work.
Same.thing is like with film where you do a more exposure to have more density on negative emulsion. Most of cinema sensors like bmd, arri sensor like to have many light as possible, and have a better management of highlights and overexposure than lowlight.
Sensor like red allow you to recover better underexposed picture, in same certain situation, but not ever or you find noise and fixed pattern from dark.
If you want to shoot in low low light red and Sony give better result with their tech, but you found a different picture that cinema picture, be cause cinema picture are 20% sensor and color science and 80% good and right lighting.

Anyway to recover overexposed picture there are more way. From move up exposure from camera raw then go down with gain (this reduce a bit the noise), up with power windows only lighting section. Later you can you use noise reduction to have less noise, but if is very underexposed you can ask miracle.
I used in 2013 cinema camera to a feature film also in.very difficult situation of light but is not a dark.camera, can give you very good picture, manage it very carefully, don't try to transform.black in details and you can have good picture.
If you post a dng we can suggest more strategy to help you.

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