Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-07-2016, 01:06 PM   #1
Pentaxian




Join Date: Oct 2013
Posts: 878
Issue with 16 bit Pixel Shift Stacked image

I got my K1 a few days ago. One of the projects I am working on has to do with wine. I have acquired a few "cheap" LED lights so that I can take advantage of the PS in K1. I tired a rough test set up today and came across some strange results. This a 4-shot stacked set up and each of the 4 shots is also a PS image.

I processed and stacked the mages with Photoshop. When I zoomed in I noticed this strange checker pattern in the dark areas (see the screen shot). I was really disappointed to see this as I am not sure what was causing it. BTW, I processed the images with 16bit depth. When I went to save the JPEGs for this post, I converted the images to 8-bit depth. I noticed that the checker pattern issue went away. I did a screen capture of the 16-bit image to show the problem area.

Has anyone else noticed this phenomenon. I will try Silkypix to see if the processed 16-bit images exhibit the same problem.

The lens is a Tamron 70-200 shot at 150mm at f4.5 at 1/6 second.

Any comments or suggestions are welcomed.

Thanks,
Boris

Attached Images
View Picture EXIF
PENTAX K-1  Photo 
View Picture EXIF
PENTAX K-1  Photo   
Attached Images
File Type: psd Napa Cellers SR pic - 4 shots - CROP.psd (1.59 MB, 67 views)

Last edited by btnapa; 06-07-2016 at 01:44 PM. Reason: typo
06-07-2016, 01:20 PM   #2
Pentaxian
RAART's Avatar

Join Date: Apr 2013
Location: Oakville, ON
Photos: Gallery
Posts: 935
I thought that this was a reflection somehow... Not easy to see it anyway.
06-07-2016, 01:26 PM   #3
Site Supporter
kiwi_jono's Avatar

Join Date: Dec 2009
Location: Christchurch, New Zealand
Photos: Gallery | Albums
Posts: 1,085
Sorry I can't see the problem area (unless I'm mistaking it for a reflection)?
06-07-2016, 01:29 PM   #4
Pentaxian




Join Date: Oct 2013
Posts: 878
Original Poster
QuoteOriginally posted by kiwi_jono Quote
Sorry I can't see the problem area (unless I'm mistaking it for a reflection)?
Sorry guys. I guess it did not come through as well as I thought. It is a faint checker pattern in the dark areas. I'll try to upload another image of the problem area.

06-07-2016, 01:30 PM   #5
Pentaxian
RAART's Avatar

Join Date: Apr 2013
Location: Oakville, ON
Photos: Gallery
Posts: 935
QuoteOriginally posted by kiwi_jono Quote
Sorry I can't see the problem area (unless I'm mistaking it for a reflection)?
It is on the last picture (screenshot) on the left from umbrella reflections. There are two types of the pattern there therefore I thought first it was reflections but it is to geometrical...

---------- Post added 06-07-16 at 04:32 PM ----------

QuoteOriginally posted by btnapa Quote
Sorry guys. I guess it did not come through as well as I thought. It is a faint checker pattern in the dark areas. I'll try to upload another image of the problem area.
Why you do not upload somewhere raw file of finished PS image (PS file or Tiff)...
06-07-2016, 01:44 PM   #6
Senior Member




Join Date: Apr 2016
Location: Los Angeles
Posts: 137
Can you put a levels layer over it to bring out the pattern more? I can see it faintly in the third image.

Is this, by any chance using the ProPhoto RGB color space and you have hardware acceleration enabled in your PS preferences? If so then turn off hardware acceleration or temporarily convert the image to AdobeRGB (or any other color space) and see if the problem goes away.
06-07-2016, 01:47 PM   #7
Pentaxian




Join Date: Oct 2013
Posts: 878
Original Poster
QuoteOriginally posted by RAART Quote
It is on the last picture (screenshot) on the left from umbrella reflections. There are two types of the pattern there therefore I thought first it was reflections but it is to geometrical...

---------- Post added 06-07-16 at 04:32 PM ----------



Why you do not upload somewhere raw file of finished PS image (PS file or Tiff)...
I just uploaded a PSD file. I had to res it down to keep the size within the 3MB file limit of PF. Hopefully it shows better.
06-07-2016, 01:47 PM   #8
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
If you do ctrl + a few times (to magnify) I can see it very clearly on the bottom image. It's a new one to me, sorry, can't help. It sounded it might be PS misalignment which produces a lattice-like pattern, but it's not the same as that.

06-07-2016, 01:49 PM   #9
Pentaxian




Join Date: Oct 2013
Posts: 878
Original Poster
QuoteOriginally posted by paulster Quote
Can you put a levels layer over it to bring out the pattern more? I can see it faintly in the third image.

Is this, by any chance using the ProPhoto RGB color space and you have hardware acceleration enabled in your PS preferences? If so then turn off hardware acceleration or temporarily convert the image to AdobeRGB (or any other color space) and see if the problem goes away.
See my last upload. When you save it as a flat file, the issue goes away. So I included a PSD with the layers. I think the problem is in the stacking process for some reason or another.

---------- Post added 06-07-16 at 01:52 PM ----------

QuoteOriginally posted by Nass Quote
If you do ctrl + a few times (to magnify) I can see it very clearly on the bottom image. It's a new one to me, sorry, can't help. It sounded it might be PS misalignment which produces a lattice-like pattern, but it's not the same as that.
Exactly. It is a random lattice pattern. I am coming to the conclusion that the problem is happening in the stacking process. Luckily, as you flatten the image or convert from 16-bit to 8-bit the problem goes away.
06-07-2016, 01:58 PM   #10
Senior Member




Join Date: May 2015
Posts: 137
If it's only visible in photoshop it's probably an artefact of the image preview. Photoshop uses a lot of acceleration and tricks to speed up and make the view responsive. As long as the exported file is fine I wouldn't worry about it. I can only see it in your screendump. It's not visible in gimp on my computer.
06-07-2016, 02:22 PM   #11
Pentaxian
12345's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 487
Interesting, because I just looked at PF's in-depth review of the K-1, and noticed a similar geometric pattern in the ISO 204,800 pixel-shifted shot. Here's what I mean:


s24-ps-nnr-204800_160519_77p-cr on Flickr

Here's an exaggerated example so you can see better what I'm talking about.


s24-ps-nnr-204800_160519_77p-cr-ed on Flickr

It might just be something to do with the super high ISO speed, but I thought it was interesting, nonetheless.
06-07-2016, 02:30 PM   #12
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
That's starting to look a bit like the lattice problems I had with PS on K3ii, on the blue shot. But mine wasn't as regular, mainly just areas of lattice. I can't remember who or what site, but I was browsing recently and some respected photography reviewer site also saw the same thing (but also irregularly patterned like mine, not in a grid like yours). It's a known PS ?artifact (he had some fancy name for it, just can't remember sorry).
06-07-2016, 02:46 PM   #13
Pentaxian




Join Date: Oct 2013
Posts: 878
Original Poster
QuoteOriginally posted by Nass Quote
That's starting to look a bit like the lattice problems I had with PS on K3ii, on the blue shot. But mine wasn't as regular, mainly just areas of lattice. I can't remember who or what site, but I was browsing recently and some respected photography reviewer site also saw the same thing (but also irregularly patterned like mine, not in a grid like yours). It's a known PS ?artifact (he had some fancy name for it, just can't remember sorry).
Nass, thank you for your feedback. I just wanted to make sure I was not imagining stuff. As I mentioned above, it looks like a Photoshop stacking issue perhaps caused by something in the pixel shift files. It also happens in the 16-bit not the 8-bit files. Go figure.
06-07-2016, 03:15 PM   #14
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,265
QuoteOriginally posted by btnapa Quote
Nass, thank you for your feedback. I just wanted to make sure I was not imagining stuff. As I mentioned above, it looks like a Photoshop stacking issue perhaps caused by something in the pixel shift files. It also happens in the 16-bit not the 8-bit files. Go figure.
QuoteOriginally posted by btnapa Quote
Nass, thank you for your feedback. I just wanted to make sure I was not imagining stuff. As I mentioned above, it looks like a Photoshop stacking issue perhaps caused by something in the pixel shift files. It also happens in the 16-bit not the 8-bit files. Go figure.
Do you see it when you develop the same file in PDCU?

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

06-07-2016, 04:25 PM   #15
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,483
QuoteOriginally posted by btnapa Quote
This a 4-shot stacked set up and each of the 4 shots is also a PS image.

I processed and stacked the mages with Photoshop.
Sorry to be dumb, but what does this mean? Are you saying that you extracted the four DNG by some unknown process and are combining them manually in PS?


Steve
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!
color, depth, dslr, full frame, full-frame, hardware, image, images, k-1, k1, pattern, pentax k-1, pixel shift, process, ps, reflections, screen, shot, space, steve, time, upload
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
a bit worry about 28-105mm's image quality rlatjsrud Pentax SLR Lens Discussion 102 03-12-2016 11:02 AM
16 Bit On The 645z? 72ndPoolShark Pentax Medium Format 9 04-13-2015 11:06 AM
How the 12-bit prime II image engine get 14-bit raw file? lapiovra Pentax K-5 9 12-30-2011 06:10 PM
Issue with Bridge (CS 5.1) Can't open image with Right Click Win 7 PC Peter Zack Digital Processing, Software, and Printing 2 12-06-2011 04:32 AM
what is the difference bwt exporting to 8-bit or 16-bit tiffs? rdrum76 Photographic Technique 3 01-22-2009 01:51 PM



All times are GMT -7. The time now is 05:24 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