clipping in REDCINE? (with examples)

[Miguel "Macgregor" De Olaso]

Hi, i´ve been playing with some footage today and i discovered some hidden info in the highlights that can be recovered lowering the ASA setting. As far as i understood the premature clipping only occured in the early RED ALERT software.
I´ve exported the same frame into 10bit DPX log and 709 gamma curves.

At 320ASA the highliths on the head of the horse cannot be recovered. I´ve tried to do so in Speedgrade DI and photosop.

ISO 320. Taken at ISO 320.


Lowering the same frame at 200 ASA brings detail to the overexposed areas. There is no problem lifting the image to a desirable state in Speedgrade DI in which the image is not underexposed and the highlights retain detail.

ISO 200. Taken at ISO 320.

So this post goes to the REDCINE engineers:
Is redcine actually cutting the information in the highlights and overexposed areas? If i can get to see information that wasn´t there before by lowering the ASA setting of the RAW image, that means REDCINE is not showing me all the information contained in the R3d.

 

[Graeme Nattress]

The software always displays all the image data that it can as dictated by the image processing settings.

The settings dictate what you see. There is a small 0.4 stop of headroom in the default settings. If you in post drop exposure approximately 0.4 EV, you will see "everything", but the exact number is dependent upon the white balance.

You should really just keep the ASA setting the same and just lower the "exposure" setting though.

Graeme

 

[Miguel "Macgregor" De Olaso]

Graeme sorry, the links were off.
What´s the reason for that 0.4 headroom?

 

[Graeme Nattress]

That's just the default setting. You can remove it by setting exposure to -0.4 in camera. After all, it's just metadata. It doesn't effect what was recorded.

If you read DPReview when they do dynamic range tests, they also mention when they expose in the raw developer for max DR, that the highlight colours are not "guaranteed". Same with RED, which is the nature of differential clipping in highlights. We've "solved" that in post with the "hightlight" correction tool, or DRX, but that feature is not in camera.

Graeme

 

[Cüneyt Kaya]

how to use the highlight correction tool?

how to use the highlight correction tool?

question about the highlight correction tool

you can set it from 0-100 .....

how does it work exactly....i mean what does it mean to set it to lets say 45,5...

or even better...how could i use the highlight correction tool "right" with the horse example?

thanks

 

[Jay A. Kelley]

That's just the default setting. You can remove it by setting exposure to -0.4 in camera. After all, it's just metadata. It doesn't effect what was recorded.

If you read DPReview when they do dynamic range tests, they also mention when they expose in the raw developer for max DR, that the highlight colours are not "guaranteed". Same with RED, which is the nature of differential clipping in highlights. We've "solved" that in post with the "hightlight" correction tool, or DRX, but that feature is not in camera.

Graeme

Graeme (Mac please forgive me for highjacking this thread for a moment).

As you know there are a LOT of people out there who are trying to render a Quicktime file only to see the first frame stuck on playback in QT. There have been numerous complaints about this, yet I have heard very little from RED about a fix, or making this software more stable.

Are you aware of these problems, is there a build coming that insures a more stable platform? My system is brand new, using an 8800 GTX card.

I personally was able to get some progress with this issue, but it's spotty and a lot of people need more help. As stated in the Upload thread, I uploaded my LogFile on 1/10/08 and have yet to hear any helpful advice from anyone on RED.

Just curious

Jay

 

[Graeme Nattress]

Jay, all software is constantly being worked on for bug fixes and improvements.

Kaya, the highlight correction tool has a "strength" setting, which governs how much of the effect is added into the image. 50% is usually about right, but if you want it off, set it to 0%. Sometimes it needs a little tweak depending on colour temp and how hot the highlight is, and what colour it is.

Graeme

 

[galexander]

Graeme (Mac please forgive me for highjacking this thread for a moment).

As you know there are a LOT of people out there who are trying to render a Quicktime file only to see the first frame stuck on playback in QT. There have been numerous complaints about this, yet I have heard very little from RED about a fix, or making this software more stable

.stuff deleted...

Jay

jay follow the rabbit and see where i've been posting about 10-bit versus 16-bit work flows, QT, and Cineform. the answers are actually there, there are actually quite a few pros here outside of Red..... i just don't have to correlate all of the information to boil it down succinctly but read the posts.

 

[Patrick Tresch]

there are actually quite a few pros here outside of Red..... .

I've tried to follow your interesting posts... It's true that there are impressive people putting their brain together to find out solutions.

Sorry I've not that level of knowledge so its true that a faq about FCP/redcine/Lut/output (DPX/TIFF) would be great.:sorcerer:

Thanks for your work Galexander.

Pat