Dumb question: What's this?

Discussion in 'General Discussion' started by hans, Oct 8, 2005.

  1. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    I'm getting this on every shot I take,the light stripes,what am I doing wrong please help me out here
    Night or day shots it's always there,when opened in NC4

    DSC_0003.

    This is the result in PSCS2

    [​IMG]

    Both only cropped and resized
     
    Last edited by a moderator: Oct 8, 2005
  2. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    It's banding! Are you under-exposing then raising the exposure level, especially in 8 bit mode?
     
  3. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    No Chris these are straight out of the box,have it with every shot day or night
    never had it before it's there with the 17-55 and the 28 1.4 didn't see it with the 70-200 or the 10.5
     
  4. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Hans, I hate to keep asking questions, this is nef, right? I have seen this in some of my own photos, especially where I underexposed to get a very dark blue sky. I thought it was caused by not enough bits to accurately represent all the hues and tones of a dark sky. I cured my problem by increasing the exposure, then removing it in post, and processing in 16 bit mode. Now however, you've got me wondering - because it's dependent on the lens.

    If this is processed 16 bit from a nef and your sky is at least one f-stop from the left wall of the histogram, then I'm stumped. I'm gonna look for a file of mine that has this and think about it some more. I'm sure that someone who knows the answer will come along and explain it to us. At least I hope so!
     
  5. heiko

    heiko

    May 15, 2005
    Israel
    Could it be something on the lens, like a smear? Just a wild guess.
     
  6. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Chris,yes they are Neff's strange thing when I open in NC the banding is visible ,in PSCS it's not, the banding becomes vissible when I save as JPG.

    Sure hope someone knows
     
  7. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Heiko,thought that first cleaned everything ,same result

    Also it's there with or without circ polarizer
     
  8. jb007

    jb007 Guest

    Hans, it's definitely "posterisation" to avoid, you need to deliberately "expose to the right" such that more of the available information is retained, then in post-processing restore it back to the correct (e.g. above) appearance. If you take a reference pic like the above, then some exposed 'to the right', use 16-bit throughout, and are careful in your processing this can and will be avoided. Why not try that, then let us know, ideally show us, what happens?
     
  9. nfoto

    nfoto Guest

    Posterisation or banding results from too much massage on image data which are too small (8 instead of 16 bits). Make the exposure on the verge of blowing out the highlights, then darken afterwards on the converted image, that should help.

    If your pictures ar labelled correctly, the first one (NC4) hasn't banding and the second (PS) has it. So presumably it's a flaw in the raw file converter factored into the result as well.
     
  10. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Image processed in PSCS 16 bit saved as 8bit JPG
    [​IMG]

    As mentioned herefore,blow the highlights darken afterwards, it looks fine up till the moment I copy them to my web-site

    Another example with blown highlights,first is NC 4 second PSCS2 16 bit saved as 8bit JPG again the CS pic looks fine before copy to the web

    [​IMG]

    [​IMG]
     
  11. nfoto

    nfoto Guest

    Hans: " again the CS pic looks fine before copy to the web".

    Ok, so you have an issue with sRGB then. Not surprising since sRGB is a smaller colour space than Adobe RGB. Somewhere in the gamut of colour there have to be converting issues, as you see clearly here.

    Suggest you add a little Gaussian blur to help fight banding in these images. Or keep your Adobe RGB space and add some more saturation, not converting for web at all. Just to give a few pointers for further experimentation.
     
  12. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Another thing to consider when dealing with two color spaces, is to convert to the new colorspace, not to assign the new space.
     
  13. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    I'm shooting in sRGB monitor is in sRGB
    I'll shoot this evening again I'll keep you informed
     
    Last edited by a moderator: Oct 8, 2005
  14. RFCGRAPHICS

    RFCGRAPHICS

    Apr 30, 2005
    Hi Hans,

    I have seen this kind of banding also with some of my night time images. Everything looks great in photoshop but when I save to jpeg format, banding can be seen in the subsequent jpeg file. Since I shoot and edit in srgb, I came to the conclusion that this banding which is not present while editing, is caused by jpeg compression algorithms. In my case, the banding only occurs in my night time skys.


    Simple test: save your image in tiff format and see if it still occurs when you view your file.

    In my cases I have also seen a difference depending on if I use PSCS or NC for my raw converter. How this figures into this anomaly is unknown to me !



    Regard

    RFC
     
    Last edited by a moderator: Oct 8, 2005
  15. More importantly: does this banding show in printing or only on a monitor???? .... I'm suspecting that it disappears in printing. Try it out. I had this happen in a pano from Greece with a LOT of blue sky. Banding on my screen but nothing in the print. Just the monitor separating the slight variations in colour.
     
  16. I second this, I have seen this as well, and my solution was not to compress as hard when using SAVE for Web in PC CS


     
  17. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Two from this afternoon,it's still there,after working in NC4 they look nice no banding showed same thing happens when copy for the web

    [​IMG]

    [​IMG]

    First is with less sky but it's still there

    Robert they look allright brfore going to the web,out of the camera there is the same amount of banding as is seen now,I can't follow it never had it before and as you know I'm always aiming for the sky.

    Sandi I don't print,just view on the puter,however they must be allright on both.
     
  18. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    It looks to me like a compression issue. If you save at maximum JPEG quality, is the iisue still there? On DSC_0003-1 I definetly see JPEG compression artifacts. One more thing - try downloading your photo from the web and open it in Photoshop. Do you still see banding?
     
  19. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Bjorn, I tried your suggestion with the following result,again they look fine before going to web

    [​IMG]

    [​IMG]

    [​IMG]
     
  20. hans

    hans

    827
    Feb 5, 2005
    The Netherlands
    Iliah,it still there in max. quality JPEG,shall try downloading and opening in Photoshop
     
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