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02-18-2017, 08:23 PM   #1
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Banding in RAW files (K5 and DA*16-50) - what's going on?

So, I am getting some pretty heavy banding in recent photos I took.
The set up:

Pentax K5
DA*16-50

Of course, I browsed a few threads on the matter and even returned to this one:
JPEG banding? What is it? how do I fix it? - PentaxForums.com
where I posted a few posts of my own in there,
Problem is, this time for me, the banding shows in DNG files as seen with FastStone Viewer and Photoshop CS5.
I thought this was a JPEG compression problem only but obviously not.

Here are a few samples:
https://www.flickr.com/gp/rdlphotos/8hVBo9
Those images are actual Print Screen shots (direct from computer monitor) while viewing with FastStone viewer. The saved images were then saved as TIFF files and uploaded to Flickr.

My question: What's going on ??

02-18-2017, 08:34 PM   #2
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QuoteOriginally posted by jpzk Quote
Problem is, this time for me, the banding shows in DNG files as seen with FastStone Viewer and Photoshop CS5.
I thought this was a JPEG compression problem only but obviously not.
Are you sure you are looking at the converted RAW and not one of the embedded JPEG images? There is a long history on this site of banding in FastStone preview images.


Steve
02-18-2017, 09:08 PM   #3
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QuoteOriginally posted by stevebrot Quote
Are you sure you are looking at the converted RAW and not one of the embedded JPEG images? There is a long history on this site of banding in FastStone preview images.


Steve
Thanks for the reply.
Here's what I did:

Took the SD card out of the camera (RAW shots)
Took that SD card into the card reader and opened with FastStone Viewer.
The image shows as a "DNG" ((from what I can see on the top right in green letters, such as K5F_8807.DNG (4928 x 3264=16.08 MP,
24,489 KB) (17/41
))
Take a Print Screen of that.
Goto Paint and save as TIFF
Upload to Flickr.

Ooops ..... When I take that RAW shot and import it into Camera RAW ... there's no banding to be seen ! ???
(I just did that a minute ago).

I'll post some pics in a few minutes.

---------- Post added 02-18-17 at 11:27 PM ----------


I added one image (no banding seen in Camera RAW) to that album ... let me know if you can see all 5 images please.

Last edited by jpzk; 02-18-2017 at 09:32 PM.
02-18-2017, 09:34 PM   #4
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QuoteOriginally posted by jpzk Quote
Take a Print Screen of that.
Smoking gun...you did a screen grab of one of the preview JPEGS. Pentax DNG files embed a FULL RESOLUTION JPEG as well as a couple of smaller ones that are available for quick preview and thumbnail use. FastStone will generally display the JPEG unless RAW development is explicitly requested. You can use dcraw to extract the JPEGs for comparison. I believe that ExifTool can also be used to extract the JPEGs.


Steve

02-19-2017, 01:37 AM   #5
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There are two ways of not displaying the embedded JPG in Faststone: you can set the default display option to 'actual size (slower)' in 'settings', or press the A key per picture as it needs more processing power.

FS has some good editing tools but does not generate developed RAWs of the same quality in terms of things like noise control that you get with DCU5.
02-19-2017, 03:37 AM   #6
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Even if Faststone as set to display the actual size of RAW files it's not the RAW file you see on your screen! Your DNG are converted to fit your screen (and other hardware). Size are no longer 4928 x 3264. + +... When you make "a picture of what you actually see on your screen" and paste this into anohter software then you are loosing a lot of information/quality.

Just try to make a picture by your K5, then grab your mobile phone and make a picture of the preview on the back LCD panel. ( Which shows a small version of the embedded JPEG FastStone use by default).

ExifToolGUI easily extract the preview JPEG by the menu; >Export/import, >Extract preview image from selected DNG. (Default size: 640 x 480).

Last edited by Dabola; 02-19-2017 at 03:43 AM.
02-19-2017, 10:13 AM   #7
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Thanks a bunch, guys !!
I appreciate the replies very much so.
I will try to tweak the FastStone settings as proposed but now ?

What do I do in order NOT to get banding in my final images:
I know now that if I take any of those RAW files and import them into Camera RAW, there is no banding to be seen.
I would presume that if I convert that to JPEG's, there will be banding?
What if there is another file format which won't show banding? What should I do from there (Camera RAW) in order to have "final" images with no banding?

JP

02-19-2017, 11:43 AM   #8
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The image is at some point being converted to an 8-bit display. Some displays are worse than others.
(potential downside of using a 10bit display -- you may not see it, but everyone else will)
Some color ranges are also going to show banding more than others.

This is pretty much going to happen regardless of format, but TIF or PNG is going to give you the option for lossless compression and result in less compression-based banding. Naturally file sizes are affected and this may not be desirable but it will help eliminate one of the causes.

To help eliminate it further, you can add a *tiny* amount of noise to the area to help blend the gradient and remove most/all of the banding effect. (tiny: enough to blend the gradient but not enough to actually see the noise)
02-19-2017, 01:25 PM   #9
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QuoteOriginally posted by jpzk Quote
I know now that if I take any of those RAW files and import them into Camera RAW, there is no banding to be seen.
I would presume that if I convert that to JPEG's, there will be banding?
Give it a try and prepare to be relieved. The preview images have a fair amount of compression. Convert to JPEG with high quality (low or no compression) and the results should be fine.


Steve
02-19-2017, 04:09 PM   #10
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QuoteOriginally posted by jpzk Quote
I would presume that if I convert that to JPEG's, there will be banding?
See the first example here- Jeffrey Friedl's Blog » An Analysis of Lightroom JPEG Export Quality Settings.

Actually look at all the examples, they show how various levels of Jpeg compression affect image quality. The first example happens to have a sky with a gradient, you can see where banding shows up. Be warned that the compression levels referenced are Lightrooms and won't directly correspond with Faststone, but can be translated to photoshops 0-12 scale. And of course it will depend on the specific image, your viewing conditions, and your tolerance for when banding or other artifacts become an issue. It's best to test out various compression settings yourself, but this is a handy and well done page to give you some idea.


QuoteOriginally posted by stevebrot Quote
The preview images have a fair amount of compression. Convert to JPEG with high quality (low or no compression) and the results should be fine.
I don't think most popular software has a lossless jpeg format (I think that's what you mean by 'no compression')? 100 (or whatever a programs max) Jpeg quality will still be lossy for any real world photograph.

The embedded preview is a funny thing, out of my k5iis, the full resolution version jpeg previews (extracted using "Instant JPEG From Raw") generally range from 1 to 1.5MB. It seems it picks a compression level to keep the file size in this range. Depending on the image content, this varies from very low to very high jpeg compression (examined using "JPEGSnoop").
02-19-2017, 07:21 PM   #11
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QuoteOriginally posted by amoringello Quote
The image is at some point being converted to an 8-bit display. Some displays are worse than others.
(potential downside of using a 10bit display -- you may not see it, but everyone else will)
Some color ranges are also going to show banding more than others.

This is pretty much going to happen regardless of format, but TIF or PNG is going to give you the option for lossless compression and result in less compression-based banding. Naturally file sizes are affected and this may not be desirable but it will help eliminate one of the causes.

To help eliminate it further, you can add a *tiny* amount of noise to the area to help blend the gradient and remove most/all of the banding effect. (tiny: enough to blend the gradient but not enough to actually see the noise)
TIFF it shall be.
I am trying to avoid too much PP (not great at this) so adding noise/blending gradient ... etc. might be more of a chore for me.
02-19-2017, 07:25 PM - 1 Like   #12
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QuoteOriginally posted by BrianR Quote
And of course it will depend on the specific image, your viewing conditions, and your tolerance for when banding or other artifacts become an issue.
Yes, it absolutely depends on the image. Notorious examples are wide angle shots of open blue sky in an 8-bit image with compression.

QuoteOriginally posted by BrianR Quote
I don't think most popular software has a lossless jpeg format (I think that's what you mean by 'no compression')?
All JPEGs are lossy. By "low or no compression", I meant from a user interface point of view.

Of course, little of that has to do with the OP's concern.

Threads related to banded preview images in FastStone have a history on this site going back almost a decade. The conventional "fix" is to point out the problem and suggest processing the RAW with settings that are unlikely to produce banding.

FWIW, as noted in the original post,the OP participated in a recent thread on the same subject. The examples and explanations on that thread are pretty good. This one pretty much tells the story:

https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/339267-...ml#post3900455


Steve

Last edited by stevebrot; 02-19-2017 at 07:42 PM.
02-19-2017, 07:42 PM - 1 Like   #13
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QuoteOriginally posted by stevebrot Quote
Give it a try and prepare to be relieved. The preview images have a fair amount of compression. Convert to JPEG with high quality (low or no compression) and the results should be fine.


Steve
OK, now I have this right.
No banding now in the "final" image, as long as I use CS5 ... Camera RAW and process to high quality JPEG (works with a TIFF file too).
Also worked with PDCU5 ... something I hadn't used for a while.
Cheers!

---------- Post added 02-19-17 at 09:44 PM ----------

QuoteOriginally posted by BrianR Quote
See the first example here- Jeffrey Friedl's Blog » An Analysis of Lightroom JPEG Export Quality Settings.

Actually look at all the examples, they show how various levels of Jpeg compression affect image quality. The first example happens to have a sky with a gradient, you can see where banding shows up. Be warned that the compression levels referenced are Lightrooms and won't directly correspond with Faststone, but can be translated to photoshops 0-12 scale. And of course it will depend on the specific image, your viewing conditions, and your tolerance for when banding or other artifacts become an issue. It's best to test out various compression settings yourself, but this is a handy and well done page to give you some idea.




I don't think most popular software has a lossless jpeg format (I think that's what you mean by 'no compression')? 100 (or whatever a programs max) Jpeg quality will still be lossy for any real world photograph.

The embedded preview is a funny thing, out of my k5iis, the full resolution version jpeg previews (extracted using "Instant JPEG From Raw") generally range from 1 to 1.5MB. It seems it picks a compression level to keep the file size in this range. Depending on the image content, this varies from very low to very high jpeg compression (examined using "JPEGSnoop").
I finally settled the "problem" ... direct to CS5 --- Camera RAW --- TIFF (or a high quality JPEG) = no banding !
As I also told Steve: also works with DCU5.
Cheers!
02-19-2017, 07:56 PM   #14
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QuoteOriginally posted by stevebrot Quote
All JPEGs are lossy. By "low or no compression", I meant from a user interface point of view.
See lossless JPEG.

I guess I'm not sure what you mean by the "no compression" part then? A setting of 100 in Lightroom or 12 in Photoshop, etc. all involve compression.
02-19-2017, 07:57 PM - 1 Like   #15
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This one of the two images with NO banding; the Faststone "preview" (which I thought was a pure RAW file, was so heavily banded that it made me screech!

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