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Thread: Fringe

  1. #1

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    Fringe

    Hi, OK I took this photo early this morning with Canon 40D 10-22mm lens, tripod and my new Lee GND filter can someone please advise me what or there is a colour fringe around the large rock.
    Fringe

  2. #2
    jiro's Avatar
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    Willie or Jiro is fine by me.

    Re: Fringe

    I don't notice any.

  3. #3

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    Re: Fringe

    We really need a close up of that rock; but yes there is obviously some form of light fringing occurring there.

    This often happens at some light angles and can be impossible to avoid under suitable (or perhaps unsuitable) lighting.

  4. #4

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    Re: Fringe

    Quote Originally Posted by Geoff F View Post
    We really need a close up of that rock; but yes there is obviously some form of light fringing occurring there.

    This often happens at some light angles and can be impossible to avoid under suitable (or perhaps unsuitable) lighting.
    OK thank you here I hope is a larger image.Fringe
    Russ

  5. #5
    Moderator Dave Humphries's Avatar
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    Re: Fringe

    Hi Russ,

    That is chromatic abberationm, often called just "CA", it is a lens defect, present in almost all lenses to some extent, especially zooms.

    It will always be worst at the edges of frame because the light from ther has gone through the edges of the lens. In the centre, you shouldn't see it. On the opposite side of the picture from this, the colours (on a dark object) will be swapped; i.e. red on left and green on right. However, it isn't about a 'dark object' per se, it is about transitions from light to dark or vice versa (near the edge of a picture), so you'll also see it on light objects against a dark background.

    Some lenses display other 'colour pairs'; e.g. yellow/blue, green/magenta, or the red/cyan you have here.

    I can't see the original image (I have Tinypic issues ), but from the close up, which looks to be about a 400% enlarged crop out of the edge of a larger image (and from top left or bottom right corners), that's definitely what it is.

    There also look to be some sharpening or local contrast enhancements there too.

    Some PP software could correct that (if shot RAW), but if this started life as an in camera jpg, then you are probably stuck with it, because attempting to do that kind of thing after the jpg sharpening will probably only make things worse (just my theory, I haven't tried it).

    Best regards,
    Last edited by Dave Humphries; 12th February 2011 at 09:31 AM. Reason: expanded

  6. #6

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    Re: Fringe

    Quote Originally Posted by Dave Humphries View Post
    Hi Russ,

    That is chromatic abberationm, often called just "CA", it is a lens defect, present in almost all lenses to some extent, especially zooms.

    It will always be worst at the edges of frame because the light from ther has gone through the edges of the lens. In the centre, you shouldn't see it. On the opposite side of the picture from this, the colours (on a dark object) will be swapped; i.e. red on left and green on right. However, it isn't about a 'dark object' per se, it is about transitions from light to dark or vice versa (near the edge of a picture), so you'll also see it on light objects against a dark background.

    Some lenses display other 'colour pairs'; e.g. yellow/blue, green/magenta, or the red/cyan you have here.

    I can't see the original image (I have Tinypic issues ), but from the close up, which looks to be about a 400% enlarged crop out of the edge of a larger image (and from top left or bottom right corners), that's definitely what it is.

    There also look to be some sharpening or local contrast enhancements there too.

    Some PP software could correct that (if shot RAW), but if this started life as an in camera jpg, then you are probably stuck with it, because attempting to do that kind of thing after the jpg sharpening will probably only make things worse (just my theory, I haven't tried it).

    Best regards,
    Hi, Many thanks Dave you put my mind at rest there, I thought I had a broken lens problem.
    Again Thanks
    Russ

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