SNATH
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Cleaning Banding In The Sky...

Tue Jan 26, 2010 3:25 am

Hi all,

Quick question for you all. I have a couple of long exposures (25sec) taken with my XTi at dusk and they have some subtle, but still obvious, banding in the sky (mostly vertical banding). I was quite surprised to see that, given that they were taken at ISO 100 and I've generally only seen such banding at higher ISOs. Any ideas on how to deal with this? NoiseNinja doesn't help (if anything else, it seems to make the issue more obvious by reducing noise).

Thanks,

Tony
Nikon: we don't want more pixels, we want better pixels.
 
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cpd
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 11:49 am

Have you got some examples of it?

This might be editing that introduced it. Watch for the noise-reduction in Photoshop Camera Raw - it makes a right mess of noise reduction, introducing blotchy effects all over the sky.

Turn off Camera Raw noise-reduction and use a proper plugin instead as you've done.

Could slight vignetting be a culprit as well?

[Edited 2010-01-26 03:50:46 by cpd]
 
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dvincent
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 1:28 pm

Probably the dynamic range of the sky exceeds what your camera can reproduce, especially when being translated down to the narrow sRGB color space in 8 bit mode.

Banding's a result of not having enough levels to describe color. You could work around it by compressing the colors (removing some saturation from the sky or brightening it a tad).
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viv
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 4:11 pm

Shoot film. No more banding.
Nikon D700, Nikkor 80-400, Fuji X Pro 1, Fujinon 35 f/1.4, Fujinon 18 f/2
 
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dvincent
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 5:39 pm



Quoting Viv (Reply 3):
Shoot film. No more banding.

Analog prints can certainly band depending on reproduction methods.
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SNATH
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 5:49 pm



Quoting Cpd (Reply 1):
Have you got some examples of it?

Here's a 100% crop from one of the images (click for the full version):



I used mostly the default LR 2.6 settings and turned off noise reduction totally. I'm curious: is banding visible on other monitors too? Here's also the equalized version of the above:



Quoting Cpd (Reply 1):
This might be editing that introduced it. Watch for the noise-reduction in Photoshop Camera Raw - it makes a right mess of noise reduction, introducing blotchy effects all over the sky.

As I said, I used no noise reduction in LR.

Quoting Cpd (Reply 1):
Could slight vignetting be a culprit as well?

It's close to the middle of the frame, so I doubt it...

Quoting Dvincent (Reply 2):
You could work around it by compressing the colors (removing some saturation from the sky or brightening it a tad).

Thanks Dan, I tried that a bit and it doesn't seem to help... I'll play around with it a bit more.

Quoting Viv (Reply 3):
Shoot film. No more banding.

Viv, thank you, as always, for the constructive and helpful suggestion. Please, keep them coming.

Tony
Nikon: we don't want more pixels, we want better pixels.
 
viv
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 8:22 pm



Quoting Dvincent (Reply 4):
Analog prints

Sorry, I meant slides, of course.
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jetmatt777
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 8:23 pm

I get the same effect on my 400D. Only appears when I use long exposures, sometimes I can find it when I do normal exposures but have the ISO up past 800 or so.

The 400D doesn't seem to like low light for me.
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viv
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RE: Cleaning Banding In The Sky...

Tue Jan 26, 2010 8:32 pm



Quoting SNATH (Reply 5):
Please, keep them coming

OK, here goes: Get yourself a Nikon F6 and a scanner, shoot slides, upload the scans here. You won't regret it!
Nikon D700, Nikkor 80-400, Fuji X Pro 1, Fujinon 35 f/1.4, Fujinon 18 f/2
 
SNATH
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 12:56 am



Quoting Dvincent (Reply 2):
Banding's a result of not having enough levels to describe color. You could work around it by compressing the colors (removing some saturation from the sky or brightening it a tad).

So Dan has a point here. Checking a few more shots I noticed that the effect is more pronounced when the color of the sky was very dark magenta (a bit after the sun set). Later on, when the magenta color disappeared, the effect is considerably less obvious.

Quoting Jetmatt777 (Reply 7):
I get the same effect on my 400D.



Quoting Jetmatt777 (Reply 7):
The 400D doesn't seem to like low light for me.

I has also shot a few long exposures with my 40D that evening and the results look much cleaner... maybe I'll stick to using the 40D for this in the future.

Quoting Viv (Reply 8):
OK, here goes: Get yourself a Nikon F6 and a scanner, shoot slides, upload the scans here.

Yes, Viv, I now have a great urge to run to the nearest camera store, dump all my digital gear, and load up on film... damn, I think they are now closed. Oh well....

Tony
Nikon: we don't want more pixels, we want better pixels.
 
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acontador
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 2:18 am

Hi Tony,

I think Dan hit the nail here:

Quoting Dvincent (Reply 2):
Probably the dynamic range of the sky exceeds what your camera can reproduce, especially when being translated down to the narrow sRGB color space in 8 bit mode.

I have seen the exactly same thing, particularly on window shots at high level and in the sky on dawn/dusk shots. The effect has always been more pronounced on my 450D than on my 40D, so I blame the dynamic range capabilities of the sensor for that.
And I also noticed that increasing contrast and saturation during editing tends to highlight even more the banding, and so far I haven't found any way of correctly dealing with it.

Hope it helps  Smile
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SNATH
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 2:34 am

Hey Andres,

Great to hear from you, I hope you are well!

Quoting Acontador (Reply 10):
and so far I haven't found any way of correctly dealing with it.

I did! Thankfully, most of it was at the top of the shot so... I cropped tighter.  Smile

Seriously now, I tried various techniques tonight and nothing really worked... I'll just stick to using my 40D for such shots in the future.

Tony
Nikon: we don't want more pixels, we want better pixels.
 
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dvincent
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 2:58 am

Unfortunately, the tricks I use to defeat banding are ones geared for prints (blurring, adding noise) and are unsuitable for posting here.

Banding, especially on longer exposures, seems to be an issue for some Canon sensors (especially on the 5Dmk2) that Canon tries to address with firmware updates, but I keep reading about banding issues off and on. Unfortunately, it is probably one of the limitations of the Canon sensors... unless you shoot in a 14 bit capture mode, which I think only the 1D series does.
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viv
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 2:38 pm



Quoting SNATH (Reply 9):
dump all my digital gear, and load up on film

It is interesting that many professional photographers are doing just that, currently...
Nikon D700, Nikkor 80-400, Fuji X Pro 1, Fujinon 35 f/1.4, Fujinon 18 f/2
 
JeffSFO
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 6:45 pm



Quoting Dvincent (Reply 12):
Banding, especially on longer exposures, seems to be an issue for some Canon sensors (especially on the 5Dmk2) that Canon tries to address with firmware updates, but I keep reading about banding issues off and on. Unfortunately, it is probably one of the limitations of the Canon sensors... unless you shoot in a 14 bit capture mode, which I think only the 1D series does.

Fortunately, I've never had a problem with banding on my 5D Mark II because I shoot in full resolution RAW (21.1 megapixels), although it may occur when shooting in sRAW1 mode (10 megapixels). But for someone like me, what's the point in doing that?

Also, it has 14-bit capture mode:

http://www.usa.canon.com/dlc/control...act=GetArticleAct&articleID=2066#2

Quoting SNATH (Reply 11):
Seriously now, I tried various techniques tonight and nothing really worked... I'll just stick to using my 40D for such shots in the future.

Glad to hear you have a solution of sorts, Tony.
 
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cpd
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RE: Cleaning Banding In The Sky...

Wed Jan 27, 2010 11:06 pm



Quoting Viv (Reply 13):
It is interesting that many professional photographers are doing just that, currently...

While Hasselblad just launches a new H4D with 60mp, and every professional photographer at the tennis in Melbourne has been using Nikon D3 or Canon 1D series cameras.

It was a nice joke for a while, but it's starting to go stale.

Quoting Acontador (Reply 10):
so far I haven't found any way of correctly dealing with it.

In print, you might add some noise to the image, and when resizing it down, that should rid the image of the effect. Don't know if then running noise-reduction would clear it up. It might work, but I've never tried it.
 
Dehowie
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RE: Cleaning Banding In The Sky...

Thu Jan 28, 2010 2:24 am

Never ever seen banding in anything Canon i have ever shot.
Except for the banding that was generated by ANET on an upload of mine taken with a 50D.
I found i could make it happen by dropping JPAG quality in PS to some pretty low levels.
But in normal processing of ANY pics none has ever been evident with any of my 10D,20D,40D,50D,7D,1DMK2,MK2N,MK3,1DsMK3 or MK4...and i do a pile of night stuff..
2EOS1DX,EF14.2.8LII,17TS,85/1.2,16-35L,24-70LII,24L,70-200F2.8LII,100-400,300/400/500/800L
 
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dvincent
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RE: Cleaning Banding In The Sky...

Thu Jan 28, 2010 12:48 pm

It's not just Canons that could have banding problems, either - I also remember the Nikon D200's infamous banding issues.

These issues are pretty rare though and only affect a minority of situations. For long exposures CCD glow on older CCD sensors can be more of an issue (where a corner gets too "hot" and produces a magenta-like glow). My old KM 5D had an issue with any exposure over four seconds.

Quoting Cpd (Reply 15):
In print, you might add some noise to the image, and when resizing it down, that should rid the image of the effect. Don't know if then running noise-reduction would clear it up. It might work, but I've never tried it.

The reason you add noise to a gradient (in this case, the sky) is to break up the consistent "bands" of color due to the limited amounts of gray levels over a certain length. Dithering would probably be the best word for it. Noise reduction software can't clean up that kind of banding since it's not really a noise problem but an output medium problem.

There's also the issue of readout banding where the cemera's colum reading might have differing amplitudes over periods of time, which manifests itself in a vertical 'striping" effect. I believe this is what the 5Dmk2's firmware was supposed to address.
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