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what causes haloes?

Discussion in 'Open Discussion' started by lefty, Aug 2, 2013.

  1. lefty

    lefty Mu-43 Regular

  2. darosk

    darosk Mu-43 Top Veteran

    705
    Apr 17, 2013
    Kota Kinabalu, Malaysia
    Daros
    Possibly overly aggressive sharpening in post - particularly if one uses unsharp mask in PS.
     
  3. arad85

    arad85 Mu-43 Veteran

    477
    Aug 16, 2012
    Normally over aggressive HDR (high dynamic range) processing.

    Halos mean different things to different people. Over aggressive edge sharpening leads to ringing artefacts (see: Guide to Image Sharpening)

    The halos you are talking about there (i.e. the difference in blueness in the sky close to the horse) is due to HDR processing.
     
  4. fredlong

    fredlong Just this guy...

    Apr 18, 2011
    Massachusetts USA
    Fred
    Or getting too aggressive with lifting the shadows with the Shadow and Highlight controls. I guess that's a form HDR.

    Fred
     
  5. dwig

    dwig Mu-43 Top Veteran

    622
    Jun 26, 2010
    Key West FL
    Or an overly aggressive use of the Clarity slider in Lightroom or Adobe Camera RAW.
     
  6. arad85

    arad85 Mu-43 Veteran

    477
    Aug 16, 2012
    Neither of these give the wide halos seen between the horse and sky on the first image. I have only ever seen these effects in overdone HDR processing where "intelligent" HDR tries to combine different HDR techniques in a single image and ends up doing it badly. It's quite easy (it certainly used to be) to get photomatix to do this sort of effect. Here is a classic example:

    403px-I_finally_got_Photomatix_-1_%281267243786%29.
     
  7. Hyubie

    Hyubie Unique like everyone else

    Oct 15, 2010
    Massachusetts
    Herbert
    Subject was underexposed, and user (yes, me sometimes) attempts to adjust exposure of subject, but isn't too careful with the brush adjustment in PP that the background closest to the subject gets over-exposed.
     
  8. caimi

    caimi Mu-43 All-Pro

    Apr 13, 2012
    middle US
    Caimi caimiphotography.com
    Sainthood.
     
  9. Henk

    Henk Mu-43 Regular

    197
    Aug 18, 2010
    the Netherlands
    I agree it's sloppy masking. Look at the first image at the sky under the horse's head which the photographer forgot to mask...
     
  10. RobWatson

    RobWatson Mu-43 Hall of Famer

    A bit of fill flash drastically reduces the need for such harsh post processing. Not a direct answer but it will help reduce the halo effects!

    The close spatial proximity of large changes of intensity and the lack of precise masking will inevitably lead to such halo type effects. There are quite a few methods to end up with halos so there is not a single answer to the OP question.

    Oh, is it not a copyright problem to repost those photos?
     
  11. lefty

    lefty Mu-43 Regular

    thanks for replies.
    I linked the news article and I'm not claiming the photos as my own. Is that not good enough?
     
  12. dwig

    dwig Mu-43 Top Veteran

    622
    Jun 26, 2010
    Key West FL
    No, it's not enough.

    The images appear in the post and therefore are being reproduced without permission. This would be a copyright violation unless the images are in the public domain, are licensed under a Creative Commons license that doesn't require attribution, or you've specifically obtained permission from the owner of the images.