Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-09-2011, 04:18 PM   #1
New Member




Join Date: Apr 2007
Location: Buenos Aires, Argentina
Posts: 20
K-5 Strange pattern appears on sky's blue color

Does anybody understand why the sky's blue colour is somehow segmented or "divided" in zones? Original picture was taken in .pef showing the same strange pattern.
Lens is DA 16-50 mm

I thank you in advance for any hint.

Attached Images
 
03-09-2011, 04:22 PM   #2
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
I'm seen similar patterns in Lightroom when Lens profiles are applied, but they onyl show up on the preview and not on the exported file.

Your image has no saved EXIF data btw
03-09-2011, 04:25 PM   #3
Inactive Account




Join Date: Aug 2008
Location: Michigan, USA
Photos: Gallery | Albums
Posts: 7,485
It's the processing.

03-09-2011, 04:38 PM   #4
New Member




Join Date: Apr 2007
Location: Buenos Aires, Argentina
Posts: 20
Original Poster
I forgot to mention that I also observe the same pattern on the K-5's display, what is the easiest way to upload the exif file?

03-09-2011, 04:50 PM   #5
Site Supporter
SpecialK's Avatar

Join Date: Dec 2006
Location: So California
Photos: Gallery
Posts: 14,614
I had that same effect, but a little more pronounced, with a particular cheap graphics adapter. The integrated graphics worked better :-(

On very rare occasions when resizing a jpg, I will get a pattern of squares, like looking though a screen door...
03-09-2011, 06:00 PM   #6
Rin
Forum Member




Join Date: Nov 2010
Posts: 87
the color depth of the jpeg file has been lowered, this is how a photo in 16bit looks like
03-09-2011, 06:19 PM   #7
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,055
It's called a quantization error.

Here is an explanation I found on the PDML regarding a picture with exactly the same problem, though the camera was most likely a K20.

QuoteOriginally posted by PDML:
The weird things you are seeing are just quantization artifacts. I'd
guess that the photo is slightly underexposed: These artifacts get more
pronounced at lower levels, where each bit has to represent a larger
portion of each f-stop. By "underexposed" I mean that the original shot
was probably exposed properly as far as the "look" of the scene goes and
didn't have any clipping, it just didn't have the histogram pushed all
the way to the right. With bright photos like this, pushing the
histogram to the right yields an overly-bright, washed-out-looking
image, but one that can be brought into line in Raw conversion. Without
those artifacts (usually).

You've really got a "worst case" situation with this shot because you
have a really gradual transition of a fairly narrow range of tones over
a very wide area.
03-09-2011, 06:23 PM   #8
Loyal Site Supporter
eaglem's Avatar

Join Date: Feb 2009
Location: Perth Western Australia
Photos: Gallery
Posts: 26,346
I might be wrong but this looks like horizontal colour banding to me which can easily be corrected with a good de-noising program such as Topaz DeNoiser 5. Also, have you tried switching your RAW format to DNG which is Adobe compatible as that may help. It may pay you to do do some trial and error tests by trying different settings so you can eliminate certain possibilities that may be causing the problem.

03-09-2011, 06:32 PM   #9
Veteran Member
KungPOW's Avatar

Join Date: Nov 2007
Location: Vancouver, Canada
Photos: Gallery
Posts: 1,702
That banding is a result of reduced colour depth from either post processing, or low quaility jpeg settings in camera.

It's not a problem with your camera.
03-10-2011, 12:38 AM   #10
Veteran Member




Join Date: Nov 2010
Location: Fife, Scotland
Posts: 834
Or it could be overcompression of the JPG, if you have altered it since it came out of the camera.
03-10-2011, 03:49 AM   #11
New Member




Join Date: Apr 2007
Location: Buenos Aires, Argentina
Posts: 20
Original Poster
Many thanks for your comments to all of you, the fact is that the original picture was taken in RAW (pef) and this can also be observed on the K-5's display....
If anybody wants to have a closer look to the original pef file, please let me know.
03-10-2011, 03:54 AM   #12
Veteran Member




Join Date: Nov 2008
Location: Umeň, Sweden
Posts: 755
Yeah, you had better upload the PEF file to get better answers, I think. It is undoubtedly a quantization error but the K-5 has 14 bits per channel and some pretty amazing dynamic range so this simply should not happen. Literally no digital camera made in the past decade should exhibit quantization errors like these. Something has to be profoundly wrong here.


QuoteOriginally posted by eaglem Quote
Also, have you tried switching your RAW format to DNG which is Adobe compatible as that may help.
This is not really how it works. DNG is an open format designed by Adobe, but PEF files are just as compatible with Adobe software, as long as you've installed the proper updates. Think of PEF and DNG as containers; the data within is exactly the same no matter the format. The upside to DNG is that it is open and not camera specific, but neither format is better or worse in any way when it comes to image quality or amount of data.

Last edited by Erik; 03-10-2011 at 04:00 AM.
03-10-2011, 04:01 AM - 1 Like   #13
Pentaxian
awaldram's Avatar

Join Date: May 2008
Location: Hampshire
Photos: Gallery
Posts: 720
When looking at the 'RAW' your actually looking at the low grade jpeg sidekick file.

Its not possible to view a raw file without processing it.

As you looking at the low grade Jpeg you will see quantization error in the 'RAW' view in camera.

I f you want to double check this reprocess the raw and save a TiFF the bands should vanish.

Providing they do look, into raising the IQ of your jpeg output from whichever raw processor your using.

Last edited by awaldram; 03-10-2011 at 04:11 AM.
03-10-2011, 04:06 AM   #14
Veteran Member




Join Date: Nov 2008
Location: Umeň, Sweden
Posts: 755
QuoteOriginally posted by awaldram Quote
When looking at the 'RAW' your actually looking at the low grade jpeg sidekick file.

Its not possible to view a raw fiel without processing it.

As you looking at the low garde Jpeg you will see quanization errror in the 'RAW' view in camera.

I f you want to doubel check this reprocess teh raw and save a TiFF the bands should vanish.

Providing they do look, into raising the IQ of your jpeg output from whichever raw processor your using.
You are essentially correct but I shoot RAW exclusively and I have NEVER seen this sort of banding even on the low quality preview JPEGs. Furthermore, there is no trivial way of extracting the low quality JPEG from the RAW file so if the OP has developed the RAW file and saved as a JPEG (and not a low quality one, either, judging from the detail present in other areas of the photo, and the fact that the JPEG is indeed 24-bit, not 16 as someone assumed) then that is not the issue.
03-10-2011, 04:18 AM   #15
Pentaxian
awaldram's Avatar

Join Date: May 2008
Location: Hampshire
Photos: Gallery
Posts: 720
QuoteOriginally posted by Erik Quote
You are essentially correct but I shoot RAW exclusively and I have NEVER seen this sort of banding even on the low quality preview JPEGs. Furthermore, there is no trivial way of extracting the low quality JPEG from the RAW file so if the OP has developed the RAW file and saved as a JPEG (and not a low quality one, either, judging from the detail present in other areas of the photo, and the fact that the JPEG is indeed 24-bit, not 16 as someone assumed) then that is not the issue.
The blue channel is blown causing the effect, This maybe because the jpeg container cant hold it , or the RAW was over exposed I cant tell.

Last edited by awaldram; 05-22-2014 at 04:20 AM.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, k-5, k-5 ii, k-5 iis, k5, pattern, pentax k-5
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Blue Color Cast to my Color Negative Prints Slowpoke Rodriguez Film Processing, Scanning, and Darkroom 9 11-20-2010 09:27 PM
M50mm F1.4 - strange color rupi Pentax SLR Lens Discussion 5 07-27-2010 02:41 PM
Strange K10D noise pattern miriya Pentax DSLR Discussion 6 03-15-2009 10:09 AM
Color change, strange. jmc7104 Post Your Photos! 0 10-11-2008 07:12 PM
Sky's Falling alchemy Post Your Photos! 8 08-13-2008 06:10 AM



All times are GMT -7. The time now is 05:45 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top