Can HDR Help

[Richard Lowther]

I shot a high contrast scene yesterday at a beach. The sun was hitting the white water and the talent was under the tree. I had a bunch of defused HMIs on the talent but still she was about a stop down from where the produces want her to be (not my choice I thought she looked natural at this level and not artificially lite).
But anyway they say they can't bring just her level up in post or the white will clip. Does anyone know if you can somehow use HDR in post to fix this problem?
Can't you take the take a file of the desired exposure of the Talents (only about half to one stop higher than what was shot) and mix it with the background exposure? I really don't want to re shoot this.
Thanks

 

[Steve Das]

(not my choice I thought she looked natural at this level and not artificially lite).

You are correct.

Can't you take the take a file of the desired exposure of the Talents (only about half to one stop higher than what was shot) and mix it with the background exposure? I really don't want to re shoot this.
Thanks

Yes..you can composite what you have..will be easier if shot was locked off.

 

[Dan Hudgins]

Gamma

Gamma

But anyway they say they can't bring just her level up in post or the white will clip. Does anyone know if you can somehow use HDR in post to fix this problem?

That's nonsense, when you adjust the GAMMA of the image the white and black points are unchanged, only the mid tones change.

Do you have a link to an uncompressed REDLOG 48bpp TIF of a frame you shot (using DRX processing)?

Can you make a REDLOG TIF file, I can see how much to pull up the face to be near mid-tone.

The background will get lighter yes, but it should NEVER clip from just gamma adjustments, and if there is enough noise over patches even with large gamma lift their will be some slope even near the top.

If you overexposed the background the you need to use DRX processing before gamma adjustments. If the background is very overexposed then even DRX cannot bring back want is past the sensor ADC range.

You can do a matte on the bright background and a gamma lift on the forground, but it needs to be a traveling matte. If you just make two images with different adjustments and mix them you are not getting something for the most part that cannot be had in one pass with the right curves, unless you are changing the color balance and saturation which will change a little in non-linear color space of the two (high and low) color corrections.

With the curves in color correction if the face is under the background you can put an inverse S-cure on the highlights to expand them, then flatten the crurve above the face level, then pull up the face to mid-tones in the center levels. If you want the face above the background then you may need to make a traveling matte since you are no longer having the tones in their priority.

One solution to shots like that is to hang a black net behind the actors to knock down the background to the level you can fill/bounce light up the foreground.

 

[jonnycom]

We've been shooting quite a bit of motion HDR with Red's in the last couple of months. When you shoot HDR it can be pretty amazing but it is not really possible to do in post.

Here is a test we did with our HDR rig. http://vimeo.com/12828140

If your in CA and need a real HDR shot we would be happy to help. We won't need any HMI's to make it look perfect.

 

[Jeff Kilgroe]

I shot a high contrast scene yesterday at a beach. The sun was hitting the white water and the talent was under the tree. I had a bunch of defused HMIs on the talent but still she was about a stop down from where the produces want her to be (not my choice I thought she looked natural at this level and not artificially lite).

Sunlit conditions can be hard... Sometimes you need more bounce and fill to compensate. Sometimes you have to give in and shoot at a different time of day if you can...

But anyway they say they can't bring just her level up in post or the white will clip. Does anyone know if you can somehow use HDR in post to fix this problem?

Why can't they bring her level up in post? If she is not already over-exposed or clipping, that's easy. I can't pass judgement without seeing an image to reference, but it sounds more like they're in need of an experienced image tech and/or colorist.

Can't you take the take a file of the desired exposure of the Talents (only about half to one stop higher than what was shot) and mix it with the background exposure? I really don't want to re shoot this.
Thanks

Hmmm... How would you make it all match up? There's really nothing you can do here to create HDR at this point.

Do you have a clip or even a still you can post so we can see the problem? If nothing is over-exposed and clipping, it should be possible to isolate and grade the talent. Depending on the disparity between the background ant subject exposures, it may take some more involved efforts than manipulating curves in a first-light pass... Might need to hit it in AE, Color, etc..

 

[Hrvoje Simic]

they say they can't bring just her level up in post or the white will clip.

They are wrong. One stop is not a problem.

You don't need HDR for that. You don't have to reshoot it. If they need convincing just send me a 16 bit tiff frame grab.

 

[Matt W.]

Power windows in any decent color correction suite will solve this problem easily.

Why use so many HMIs and not more bounce? Much cheaper and brighter.