problem with my r3d file - banding

[Patrick Tresch]

Hello,

I've been through the color correcting session and all material looks good. Nonetheless I have one shot that cause me trouble.

I can see some banding in the blur area that also appear in the R3D in RCx.

I would like to know what was the Redcode compression of the file but I can't find it in the meta data. Perhaps it was mistakenly set to RC28. Where do I get this info?

Has any one experienced banding with R3D files?

The camera is a Misterium X. 30.5

You can download the trimmed R3D clip here (1 frame):

http://dl.free.fr/aqgEZiYhi

Click on :

Télécharger ce fichier in the above links

to get the download started.



Help apreciated.

Patrick


PS: The Jpeg is not very demonstrative.

 

[Gunleik Groven]

I'll look at the clip, but is it 4k/2k/3k, and how are you monitoring the r3d?

Cheers

 

[Patrick Tresch]

It's a 4k 2:1 clip. I was monitoring it with Color, monitor out or HDSDI from blackmagic on a projector / also Redcine X 339 on computer screen.

It doesn't seem to be an 8bit pannel/projection issue as the problem stays while zooming in in RedcineX.

Patrick

 

[Gunleik Groven]

LOL

Pardon my french, but as it is non-existent, that wasn't too easy to download...

 

[Patrick Tresch]

:thumbup:

Here the DPX from the Color project render.

http://dl.free.fr/u1knDZczt

Patrick

 

[Gunleik Groven]

got it...

I can't see much banding, even when zoomed in. What I see is a halo around the finger (I guess the ringfinger) that comes from lights and optics I think.

(Looking at the r3d now. Will take a look at the dpx)

 

[Graeme Nattress]

I decoded the frame to a 16bit tiff and examined it in Photoshop, where it appears to be fine with no signs of posterization. I've never actually found posterization in R3D data, but obviously, it can occur in the processing pipeline. I checked with latest REDCINE-X and my reference decode.

Graeme

 

[Gunleik Groven]

In the DPX I cannot see any banding in shake either, except from the weird decode artefact at the top. But that's not really banding but just weird.

 

[Patrick Tresch]

I decoded the frame to a 16bit tiff and examined it in Photoshop, where it appears to be fine with no signs of posterization. I've never actually found posterization in R3D data, but obviously, it can occur in the processing pipeline. I checked with latest REDCINE-X and my reference decode.

Graeme

Thanks Graeme and Gunleik for taking time,

I've never seen this in another processed r3d so it was strange to me. Perhaps the problem is not in the file but on the monitoring side. As right now I'm on my Imac... I can't make extensive tests.

Good that you can't see any trouble on the r3d.

I'll look for my problem tomorrow.

Good night from Switzerland.

Patrick

 

[Jeff Kilgroe]

16bit TIFF test looks good here too. I can see a bit of banding on my 8bit DELL monitor, but that's to be expected. 1080p 444 12bit out to my Panny Plasma looks good too.

It seems I can smooth it out, even on my 8bit display by expanding the contrast range of the image. It's fairly low-con with a thin histogram. spreading that out and tweaking with curves makes it pretty smooth. The change in tone is really gradual through there, so I can see where banding or posterization would pop up on a display with limited accuracy.

 

[Graeme Nattress]

In photoshop, I use a 16bit tiff and stress the levels. I also do a dither down to 8bit to check the image as photoshop won't dither the 16 to 8 unless you specifically ask it to.

Graeme