Canon 5Dmk2 Banding / Gradient bands?

Hey guys, have been shooting with a Canon 5Dmk2 and curious if anyone has insight on a certain issue. Interested to see if anyone has any thoughts / or can tell me what causes this issue ?? At first I assumed it was jpeg compression just not being able to make smooth gradients which I noticed a while back when shooting sunsets (wasnt using RAW at the time) - the compression would occur in gradual color gradients appearing as bands..
However after seeing the same banding in RAW images today - I am not sure what to think...

Firstly all of these images have been resized and resaved in photoshop - so there is quality loss compared to the original files - however due to re-compression the issue I am investigating should become more obvious - The issue is on all these shots, both original out of camera JPEG's and original CR2 raw files - both exhibit forms of this banding - the JPEGs compression making it incredibly more obvious.

Resized Original Sunset photo (taken as JPEGS) : Canon 5Dmk2 - 24-70mm 2.8:

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No ideas?? Ive been asking around - and seems it may be something that can just happen gradual light fading if your exposure does'nt have enough detail ( pushing histogram to the right when exposing ) - thus giving the file more information to make up the transition from one color or to the other , or lightness to darkness... was just very surprised to see the effect present in CR2 files.

Sebastian....

I've been shooting with a 5D Mark II for some time now and have not experienced the problem you describe after shooting many sunset/sunrise images. I hate to speculate on what the problem may be, especially since you are seeing it in RAW images. Does it show up in prints? I was wondering if it has something to do with your computer monitor or maybe your graphics card in the computer?

Try viewing the original RAW in 16 or 32-bit color space. See if that helps.

There's only so many shades of a similar color that can be displayed in 8-bit, coupled with a lossy format like .jpeg, is probably the reason you're seeing banding - just not enough color bit depth to reproduce that subtle gradient.

Can you post a crop of the original RAW file?

That's posterization. It usually happens when you save in 8 bits format and compression (JPG).
It's typical in large monotone areas such as the sky or your wall, there are not enough tones in 8 bits to cover the transition from light to dark areas of the same hue.

To solve it you can just add a little noise, if you add some noise posterization magically disappears.

Thanks for your suggestions - Monitor / graphics card are A1. Adding just the right amount of noise made a BIG difference - and pretty much eliminated the problem

However Im thinking something is wrong with either my Method or Camera settings ??

I probably should've have paid more attention before - but this histogram is missing a lot of information .... IS this because I have underexposed too much and the banding / posterization is a result of lack of information in that mid to highlight area ?? As the posterization / banding is 100% there in the raw file when viewed in 16bit etc - before any conversion - so somehow this is happening in Camera ?

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Yes it is underexposed. You should always try to expose to the right (ETTR) then you can adjust the exposure to taste. Exposing to the right will bring the signal to noise ratio to the highest possible value for a given scene.

The banding can occur if a shot is under exposed & you try to get more detail using your software. Adding a bit of noise can help to soften the edges of the banding. File compression can also cause some banding. Adjusting highlights, shadow & midtones can help a little, but could also cause more banding if done incorrectly. Some PP software is also more prone to banding than others.

Here are a couple of links that may help you.

http://en.wikipedia.or​g/wiki/Posterization

http://www.cambridgein​colour.com/tutorials/p​osterization.htm

great thanks guys - apparently the exposure meter / histogram goes off jpeg profiles as well, so that may have thrown me - causing me to underexpose so drastically - which I usually have a habit of underexposing for fear of blowing out the highlights - which always are unrecoverable...

Will definitely be more conscious of ETTR when shooting scenes of gradual light fall off ( sunsets / sunrises / various rooms etc... ) - I think that was what primarily was the cause - as without any adjustments at all to the raw files - I could see the subtle banding occurring as it was.