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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Banding

S

sam karr

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When I underexpose my footage in redcine-x I can see banding appearing at a certain point. Is it something normal?
 
Sam,
What exactly do you mean by banding? Can you post a screenshot or send it to redcinex at red dot com? thanks.

Armen
 
Your monitor is most likely 8 bit and if it's more high end maybe 10 bit. Your footage from a Red One MX is 12 bit and Epic/Scarlet is 16bit. Your monitor cant display the complexity of the higher bit rate so it causes banding. It's not how the footage actually looks rather how your monitor displays the image.
 
here is the normal exposed one: http://www.supralumen.com/original
here is an underexposed in redcine-x one: http://www.supralumen.com/banding
It's a imac 27" screen for info.
So maybe you will not see it on your screen.
I just don't understand why the image is perfect when exposed quite normally, even on smooth gradients, but has a lot of banding when exagerating the iso toward under exposition.
 
your adding in more contrast and more gradations of grey/black. It will cause more banding. Im using a 30" Apple Cinema Display that has been calibrated. I see banding on almost all of my contrasty and dark footage. If you zoom into the footage 100% and scan the areas you won't see it.
 
Ok thanx for your replies.
I'm seeing it even at 100% in fact.
 
sam karr said:
Ok thanx for your replies.
I'm seeing it even at 100% in fact.
Click to expand...

Is your monitor calibrated?

Both images look identical to me (banding wise). Im judging by the wall on the right.
 
Be aware that all the Apple displays of which I'm aware are 8-bit.

Take your footage to a decent post house with 10-bit broadcast monitors and ask to check the footage there. A lot will depend on the nature of the exposure, the compression rate chosen, and the degree of change introduced during the color-correction process.
 
I see no banding on the correctly exposed image and significant banding on the under exposed one. 16 bit AD or not, when you under expose you throw away most of the available bit depth at the top end of the scale and there are fewer bits left to define values at the low end. Why are so many people continually under exposing footage when it isn't necessary? If you are not clipping highlights, the more exposure the better. Whatever happened to the ETTR principle? ( expose to the right end of the histogram for a "fat" image).
If you under expose film you get bad results, if you under expose digital you get bad results.
 
Thanx to all. i was just wondering in fact. Simple curiosity from a newbie. As I never really noticed that with my digital still cameras in raw.
 
I've never actually seen banding in actual R3D data - so can you please send me that frame as an R3D Trim and i'll look at it. It's most likely some kind of display artifact.

Graeme
 
Then it's some display artifacts yes. I've tried with some r3d from other users and I can notice the same banding when I push the CC heavily. Thanx Graeme.
 
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But if the grading tool is working correctly, you shouldn't induce banding from heavy grading either.

Graeme
 
sam karr said:
here is the normal exposed one: http://www.supralumen.com/original
here is an underexposed in redcine-x one: http://www.supralumen.com/banding
It's a imac 27" screen for info.
So maybe you will not see it on your screen.
I just don't understand why the image is perfect when exposed quite normally, even on smooth gradients, but has a lot of banding when exagerating the iso toward under exposition.
Click to expand...

The banding is in the bright parts of the shot, thats the area with the most data captured per stop. Bringing that down in post will not show any banding from lack of data captured because there is no lack of data.
If you do it the other way around - shoot underexposed and brighten alot in post then theoretically you could see some banding. But most often the noise structures hides any banding in these very dark areas.
What you see must be from the software or monitor part of the display chain. If the banding patterns doesn't change with zoom ratio, it isn't the monitor, then it is either your graphics card/driver or the software used.
Render out a file and play it through a proper monitor or even a quality HDTV, if it is still there you need to figure out what software is causing it as it is occuring prior to render out, if its gone it could be the grephics driver/card at play - try updating driver or try a different PC/Mac.

MHO.
 
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