the overexposure recovery on the A7s is amazing

[gelaxstudio]

This video shows the A7s can recover a lot of overexposure details during grading ,which seems impossible on a camera using 8bit  compressed codec,the result looks amazing!

 

 

[richg101]

I think his LUT is responsible for the driveway being 'six stops over' to start with.  I imagine if the ungraded s-log were to have been toggled, it wouldnt have been quite as drastic since more of the highlight detail would be visible to start with.  rather than recovering from 6 stops over, he's pulling down maybe 2 stops of original over exposure at most, and it's not showing up as too harsh in this circumstance.

 

None the less, I am blown away this was 160,000 iso!!!  At first I thought he meant 1600!    

[Guest Ebrahim Saadawi]

If he started from S-log you would have been less impressed. The A7s does seem to have a very good latitude though, but from my experience, in compressed formats, recovering overexposed highlights is practically impossible. Only place I've been able to effectively pull down highlights was raw, and film.

Some compressed formats are better than the others, but I'd say it doesn't go beyond 1 stop recovery. Don't expect too much higher and expose for those highlights!

[KarimNassar]

Like richg101 said, it is likely the LUT is shifting the tones of the footage, blowing up the highlights.

So when he is bringing them down, he is not exclusively "recovering" highlight information, but also bringing down the overexposure introduced by the LUT to begin with.

 

Now he does state in the video that from an incident reading on set, the alley is overexposed by 6 stops, and yet it retains a lot of highlight information.

[gelaxstudio]

Like richg101 said, it is likely the LUT is shifting the tones of the footage, blowing up the highlights..

 

Here are some pictures show how the s-log2 footage looks like after added the the "SLog to Rec 709 Low Contrast 1(A)" LUT

http://www.hingsberg.com/index.php/2013/07/f55-slog2-lut-samples/

 

Original S-Log footage:

 

After added the LUT:

 

The "S-Log to Rec 709 Low Contrast 1" LUT is come from sony ，after added the LUT,I did not see the highlight  completely blow up , only near 1 stop I guess,  

 

So is it really the problem caused by the LUT?

I doubt that

[sunyata]

The Slog2/SGamut LUT's that I've found included with most software are designed for the F55 and don't work for the A7s. The 3D Slog2/SGamut LUTs posted to Sony's CineAlta forum have color transforms burned in that also look specific to the F55. But actually, it's in the blacks to dark grays that banding and macroblocks are most visible, not in the mid to whites, so this might account for how surprised he is. Our eyes are more attuned to changes in dark contrast. This is why log gamma usually sets middle gray to 18% instead of 50%, which looks like pure white.

[KarimNassar]

So is it really the problem caused by the LUT?

I doubt that

 

nice before and after thanks.

I can see the wall directly next to the window blowing up, although not by much like you said. 

 

Obviously not all of the recovery displayed in the video comes from bringing back down the LUT effect on highlights.

 

It's just that it is hard to gauge how much information in the highlights is being actually recovered, and how much is displayed back by bringing down the shift introduced by the LUT.

[sunyata]

I believe those screenshots came from an F65 or F55.