K-7 - Banding in DNG but banding gone after conversion to JPG?

raider · 09-26-2010, 04:42 PM

Hi

I went for a field trip and took some pictures. As I use RAW+ in all my shootings, I have a set of DNG and JPG files on the sdcard.

When i inspected these DNG and JPG files on the computer screen using faststone viewer, it is apparent that some of the DNG files (not all, however, only a selected few) exhibit a certain degree of banding. Re the following image.
Attachment 71645

Here is a 100% crop of the DNG:
Attachment 71644

The JPG file is fine however, no sign of banding whatsoever. Re. the following image:
Attachment 71647

Puzzled why this is happening, i use Abobe Raw to convert the original DNG to JPG and sure enuf the final output JPG is totally clean, no banding whatsoever. The original DNG file under Adobe RAW is also totally clean and without banding and the conversion output is therefore also clean. It is only that when i view the DNG under fastsone viewer (and even when viewed on the K-7's 2.7" screen) that i am able to detect this banding.

I also loaded up pentax camera utility (lastest version) and use it to inspect the original DNG and on the screen, the banding on the DNG is still present but the minute i touch any of the picture settings (to change from say vibrant to mute, or any other settings), the banding on the screen is immediately gone!

I am not complaining (as the final output jpg is clean and the DNG just fine after a resave), but I would like to understand why this is happening.

Any ideas?

raider

Last edited by raider; 02-07-2012 at 06:35 AM.

creampuff · 09-26-2010, 05:11 PM

I don't use fastone viewer but I would suspect how the program renders RAW file thumbnails could be the issue. Since you have no problems with ACR, the issue would be isolated to fastone. Suggest you give Adobe Bridge a try.

raider · 09-26-2010, 05:13 PM

But why would K-7's LCD screen show this banding on the DNG file as well?

enoeske · 09-26-2010, 06:12 PM

The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't.

Eruditass · 09-26-2010, 06:19 PM

You can't display a RAW file directly. A program must interpret it for you to see it.

Originally posted by enoeske

The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't.

As enoeske said. Also, faststone may be developing a temporary image to show you.

Pentaxor · 09-26-2010, 06:46 PM

Originally posted by raider

But why would K-7's LCD screen show this banding on the DNG file as well?

probably some defective pixels. have it checked to be sure.

raider · 09-26-2010, 06:53 PM

Originally posted by enoeske

The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't.

The in-camera jpeg setting is set to maximum at 4 stars.

Originally posted by Pentaxor

probably some defective pixels. have it checked to be sure.

I am inclined to think that it is not the LCD issue as the LCD is displaying the same banding as the DNG's preview on the computer screen. If it is defective pixels on the sensor, the raw file will have that kind of defects even after post-processing.

The thing is i never have this issue since the day i bought the k-7....not a main prob however, i am just curious to know why.

m8o · 09-26-2010, 07:01 PM

How was the 1st image with the banding produced? Is that the JPEG out of the camera, and the bottom [3rd] image the JPG created from the DNG? Sorry for being 'thick' on that if that should have been clear.

creampuff · 09-26-2010, 07:02 PM

Well the best I can figure is a 12 bit RAW file has 16x more data than an 8 bit Jpeg. I doubt the camera's LCD can fully show extremely fine detail or gradation, thus you're seeing the occasional moire. Should be gone when you zoom in.

Andrew Lang · 09-26-2010, 07:09 PM

Moire usually shows up on the lcd, as creampuff said, your final image won't have it, so don't worry about it. (if you zoom in you will notice the moire on your lcd should go away)

raider · 09-26-2010, 07:09 PM

Originally posted by m8o

How was the 1st image with the banding produced? Is that the JPEG out of the camera, and the bottom [3rd] image the JPG created from the DNG? Sorry for being 'thick' on that if that should have been clear.

The 1st image is the actual screen of the DNG file as seen from faststone viewer. I use fastsone to open the DNG file and save it as an jpg file and resized to 800 x 600.

The 1st image is exactly how the image is displayed on my PC screen. As can be observed, there are slight "banding" on the sky.

The 3rd image is the JPG created from the DNG using adobe raw. Clean with no banding.

The JPG created by the K-7 as part of the RAW+ mode is also clean with no banding.

raider · 09-26-2010, 07:11 PM

by the way, is this called banding or moire or ??

enoeske · 09-26-2010, 07:42 PM - **1 Like**

its Posterization

Posterization - Wikipedia, the free encyclopedia

Eruditass · 09-26-2010, 08:38 PM

Originally posted by raider

The in-camera jpeg setting is set to maximum at 4 stars.

It's unlikely that the jpeg previews for RAW use this setting, if it is even that. More likely it is faststones's temporary interpretation.

m8o · 09-26-2010, 08:56 PM

Originally posted by raider

The 1st image is the actual screen of the DNG file as seen from faststone viewer. I use fastsone to open the DNG file and save it as an jpg file and resized to 800 x 600.
The 1st image is exactly how the image is displayed on my PC screen. As can be observed, there are slight "banding" on the sky.
The 3rd image is the JPG created from the DNG using adobe raw. Clean with no banding.
The JPG created by the K-7 as part of the RAW+ mode is also clean with no banding.

Ah, I see. It's the embedded JPG preview that Pentax RAWs include within them. I don't usually see them, as I use Lightroom and it makes its own previews out of the RAW.

What comes to mind is that to increase performance the embedded preview JPG is using 6-bit (or 7, or 5?) processing. [???] I'm currently on my work computer -- no digital photo processing software on it -- but did you do a comparison between the count of colors between the embedded JPG and the generated JPG?

09-26-2010, 04:42 PM	#1
raider Veteran Member Join Date: Jul 2007 Location: Perth, Australia Photos: Gallery Posts: 1,989	K-7 - Banding in DNG but banding gone after conversion to JPG? Hi I went for a field trip and took some pictures. As I use RAW+ in all my shootings, I have a set of DNG and JPG files on the sdcard. When i inspected these DNG and JPG files on the computer screen using faststone viewer, it is apparent that some of the DNG files (not all, however, only a selected few) exhibit a certain degree of banding. Re the following image. Attachment 71645 Here is a 100% crop of the DNG: Attachment 71644 The JPG file is fine however, no sign of banding whatsoever. Re. the following image: Attachment 71647 Puzzled why this is happening, i use Abobe Raw to convert the original DNG to JPG and sure enuf the final output JPG is totally clean, no banding whatsoever. The original DNG file under Adobe RAW is also totally clean and without banding and the conversion output is therefore also clean. It is only that when i view the DNG under fastsone viewer (and even when viewed on the K-7's 2.7" screen) that i am able to detect this banding. I also loaded up pentax camera utility (lastest version) and use it to inspect the original DNG and on the screen, the banding on the DNG is still present but the minute i touch any of the picture settings (to change from say vibrant to mute, or any other settings), the banding on the screen is immediately gone! I am not complaining (as the final output jpg is clean and the DNG just fine after a resave), but I would like to understand why this is happening. Any ideas? raider Last edited by raider; 02-07-2012 at 06:35 AM.

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09-26-2010, 05:11 PM	#2
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	I don't use fastone viewer but I would suspect how the program renders RAW file thumbnails could be the issue. Since you have no problems with ACR, the issue would be isolated to fastone. Suggest you give Adobe Bridge a try.

09-26-2010, 05:13 PM	#3
raider Veteran Member Join Date: Jul 2007 Location: Perth, Australia Photos: Gallery Posts: 1,989 Original Poster	But why would K-7's LCD screen show this banding on the DNG file as well?

09-26-2010, 06:12 PM	#4
enoeske Veteran Member Join Date: Jul 2009 Location: Surprise, Az Photos: Gallery Posts: 2,136	The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't.

09-26-2010, 06:19 PM	#5
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	You can't display a RAW file directly. A program must interpret it for you to see it. Originally posted by enoeske The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't. As enoeske said. Also, faststone may be developing a temporary image to show you.

09-26-2010, 06:46 PM	#6
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	Originally posted by raider But why would K-7's LCD screen show this banding on the DNG file as well? probably some defective pixels. have it checked to be sure.

09-26-2010, 06:53 PM	#7
raider Veteran Member Join Date: Jul 2007 Location: Perth, Australia Photos: Gallery Posts: 1,989 Original Poster	Originally posted by enoeske The preview on the camera is a preview of a jpeg. It does not show the raw data, but the embedded jpeg. Check your in camera jpeg settings (specifically, *** quality). Your raw developer may be showing you a preview using the embedded jpeg as well. ACR doesn't. The in-camera jpeg setting is set to maximum at 4 stars. Originally posted by Pentaxor probably some defective pixels. have it checked to be sure. I am inclined to think that it is not the LCD issue as the LCD is displaying the same banding as the DNG's preview on the computer screen. If it is defective pixels on the sensor, the raw file will have that kind of defects even after post-processing. The thing is i never have this issue since the day i bought the k-7....not a main prob however, i am just curious to know why.

09-26-2010, 07:01 PM	#8
m8o Veteran Member Join Date: Jul 2007 Location: 40°-55'-44" N / 73°-24'-07" W [on LI] Photos: Gallery \| Albums Posts: 3,092	How was the 1st image with the banding produced? Is that the JPEG out of the camera, and the bottom [3rd] image the JPG created from the DNG? Sorry for being 'thick' on that if that should have been clear.

09-26-2010, 07:02 PM	#9
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	Well the best I can figure is a 12 bit RAW file has 16x more data than an 8 bit Jpeg. I doubt the camera's LCD can fully show extremely fine detail or gradation, thus you're seeing the occasional moire. Should be gone when you zoom in.

09-26-2010, 07:09 PM	#10
Andrew Lang Senior Member Join Date: Oct 2009 Location: Thunder Bay Photos: Gallery \| Albums Posts: 184	Moire usually shows up on the lcd, as creampuff said, your final image won't have it, so don't worry about it. (if you zoom in you will notice the moire on your lcd should go away)

09-26-2010, 07:09 PM	#11
raider Veteran Member Join Date: Jul 2007 Location: Perth, Australia Photos: Gallery Posts: 1,989 Original Poster	Originally posted by m8o How was the 1st image with the banding produced? Is that the JPEG out of the camera, and the bottom [3rd] image the JPG created from the DNG? Sorry for being 'thick' on that if that should have been clear. The 1st image is the actual screen of the DNG file as seen from faststone viewer. I use fastsone to open the DNG file and save it as an jpg file and resized to 800 x 600. The 1st image is exactly how the image is displayed on my PC screen. As can be observed, there are slight "banding" on the sky. The 3rd image is the JPG created from the DNG using adobe raw. Clean with no banding. The JPG created by the K-7 as part of the RAW+ mode is also clean with no banding.

09-26-2010, 07:11 PM	#12
raider Veteran Member Join Date: Jul 2007 Location: Perth, Australia Photos: Gallery Posts: 1,989 Original Poster	by the way, is this called banding or moire or ??

09-26-2010, 07:42 PM - 1 Like	#13
enoeske Veteran Member Join Date: Jul 2009 Location: Surprise, Az Photos: Gallery Posts: 2,136	its Posterization Posterization - Wikipedia, the free encyclopedia

09-26-2010, 08:38 PM	#14
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	Originally posted by raider The in-camera jpeg setting is set to maximum at 4 stars. It's unlikely that the jpeg previews for RAW use this setting, if it is even that. More likely it is faststones's temporary interpretation.

09-26-2010, 08:56 PM	#15
m8o Veteran Member Join Date: Jul 2007 Location: 40°-55'-44" N / 73°-24'-07" W [on LI] Photos: Gallery \| Albums Posts: 3,092	Originally posted by raider The 1st image is the actual screen of the DNG file as seen from faststone viewer. I use fastsone to open the DNG file and save it as an jpg file and resized to 800 x 600. The 1st image is exactly how the image is displayed on my PC screen. As can be observed, there are slight "banding" on the sky. The 3rd image is the JPG created from the DNG using adobe raw. Clean with no banding. The JPG created by the K-7 as part of the RAW+ mode is also clean with no banding. Ah, I see. It's the embedded JPG preview that Pentax RAWs include within them. I don't usually see them, as I use Lightroom and it makes its own previews out of the RAW. What comes to mind is that to increase performance the embedded preview JPG is using 6-bit (or 7, or 5?) processing. [???] I'm currently on my work computer -- no digital photo processing software on it -- but did you do a comparison between the count of colors between the embedded JPG and the generated JPG?