purple edge to my bird

lynnmalynnma Registered Users, Retired Mod Posts: 5,208 Major grins
edited February 1, 2004 in Technique
Hi all,

why does my (slightly out of focus) bird have a purple edge on it's left side. I know it must have something to do with the magnification in the lens but how do I get rid of it, or avoid it.

Thanks
Lynn
website

Comments

  • WolfWolf Registered Users Posts: 154 Major grins
    edited January 31, 2004
    Are you familiar with this species of bird? From what I can tell this is a Commom Redpoll, the cap is usually a red or orange color, so if I am correct with the species your color is only slightly off. Hope this helps.
  • lynnmalynnma Registered Users, Retired Mod Posts: 5,208 Major grins
    edited January 31, 2004
    Wolf wrote:
    Are you familiar with this species of bird? From what I can tell this is a Commom Redpoll, the cap is usually a red or orange color, so if I am correct with the species your color is only slightly off. Hope this helps.
    Hi yes it is a Redpoll but I was concerned about the purple edge to the whole left edge of the bird.. some kind of refraction or something.. I've "sponged" at it a bit in Photoshop and that seemed to help a bit.
    Comments please.
    Lynn
    website
  • WolfWolf Registered Users Posts: 154 Major grins
    edited January 31, 2004
    Sorry, I am not seeing the problem that you are concerned with, maybe its just my monitor!
  • lynnmalynnma Registered Users, Retired Mod Posts: 5,208 Major grins
    edited January 31, 2004
    Wolf wrote:
    Sorry, I am not seeing the problem that you are concerned with, maybe its just my monitor!
    For a moment I got excited and thought it might be my monitor, but it prints out with a glowy edge.. I think it must be too much magnification or something.
    Funny that it's only on the left edge tho and not on the top.
    Thanks anyway.
    Lynn
    website
  • cmr164cmr164 Registered Users Posts: 1,542 Major grins
    edited January 31, 2004
    lynnma wrote:
    Hi all,

    why does my (slightly out of focus) bird have a purple edge on it's left side. I know it must have something to do with the magnification in the lens but how do I get rid of it, or avoid it.

    Thanks
    Lynn
    Unfortunately that kind of color fringing is a typical result in conversion to jpeg from GRGB sensor data and is most commonly noticeable on sharp edges against a light background.

    http://www.camerabits.com/artifacts.html
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  • Shay StephensShay Stephens Registered Users Posts: 3,165 Major grins
    edited January 31, 2004
    lynnma wrote:
    Hi all,

    why does my (slightly out of focus) bird have a purple edge on it's left side. I know it must have something to do with the magnification in the lens but how do I get rid of it, or avoid it.

    Thanks
    Lynn
    It looks like common purple fringing to me, also known as chromatic aberration. It can have a variety of causes, but optics and zooming and the interaction with the sensor probably accounts for most of the occurances.

    Ways to mitgate it include controling exposure, using smaller apertures, avoiding areas of ultra high contrast, and post processing.

    In post processing, you can adjust the saturation and brightness of the purple (magenta) to make it less visible, or you can use the clone tool set to color and paint over it. This example is using the saturation method:
    pole4web.jpg
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  • ian408ian408 Administrators Posts: 21,949 moderator
    edited February 1, 2004
    Shay,

    Perhaps you know the short answer to this. Most sensors have a "sweet
    spot"--Exposure where they perform their best.

    Is chromatic aberation lessened by shooting within the sweet spot or is
    it more a function of the lens/sensor combination? Is the problem mitigated
    by using "better" quality lenses?

    Ian
    Moderator Journeys/Sports/Big Picture :: Need some help with dgrin?
  • wxwaxwxwax Registered Users Posts: 15,471 Major grins
    edited February 1, 2004
    Lynn, do you have Photoshop? Or Photoshop Elements?

    Here's a link to an article that shows you how to do what Shay described, lowering the saturation of the magenta to get rid of the CA.

    Don't be upset about your camera having Chromatic Abberation in some shots. Almost every digital camera does, from what I can see. My G3 certainly does. It happens in high-contrast situations. I see it in my shots when I have a dark object starkly outlined against a bright background (usually the sky.) I've also had it shooting ice.
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  • lynnmalynnma Registered Users, Retired Mod Posts: 5,208 Major grins
    edited February 1, 2004
    wxwax wrote:
    Lynn, do you have Photoshop? Or Photoshop Elements?

    Here's a link to an article that shows you how to do what Shay described, lowering the saturation of the magenta to get rid of the CA.

    Don't be upset about your camera having Chromatic Abberation in some shots. Almost every digital camera does, from what I can see. My G3 certainly does. It happens in high-contrast situations. I see it in my shots when I have a dark object starkly outlined against a bright background (usually the sky.) I've also had it shooting ice.
    Thanks all, very helpful indeed... I was thinking there was something wrong with either my lens or my exposure. Also very helpful INDEED was this link regarding histograms.. I took photographs all weekend using the histogram to check for over and under exposure each time and am very pleased with the results and the learning curve that comes with it. Here's link again if anyone else wants to go look.

    http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
    website
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