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Thread: Seeking explanations for artefacts

  1. #1
    purplehaze's Avatar
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    Seeking explanations for artefacts

    I have been noticing some unusual (to me) artifacts in the OOF areas of images shot with my Nikkor 70-200 mm f/4 on both the D7100 and the D750 and am hoping that I haven't damaged it.

    This was shot at the zoo this spring. Could the weird circles visible at the top and bottom have been caused by shooting through a wire fence?

    Seeking explanations for artefacts

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    Stagecoach's Avatar
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    Re: Seeking explanations for artefacts

    Quote Originally Posted by purplehaze View Post
    Could the weird circles visible at the top and bottom have been caused by shooting through a wire fence?
    They do not look like true circles to me Janis but the 'diamond' shape of a wire fence.

  3. #3
    purplehaze's Avatar
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    Re: Seeking explanations for artefacts

    Yes, the more I look at them, the more I am reassured. Thanks, Grahame.
    Last edited by purplehaze; 8th July 2019 at 07:31 PM.

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    Moderator Manfred M's Avatar
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    Re: Seeking explanations for artefacts

    +1 to Grahame's comments. Those "artifacts" are nothing more than the out of focus wire from a chain link fence.

  5. #5
    purplehaze's Avatar
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    Re: Seeking explanations for artefacts

    Thanks, Manfred.

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    Re: Seeking explanations for artefacts

    Except for those "rings," Janis, a nice shot of an great subject.

    My question to Manfred is- How does one eliminate the unwanted things in an image like this?

    Zen

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    Moderator Manfred M's Avatar
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    Re: Seeking explanations for artefacts

    Quote Originally Posted by zen View Post
    My question to Manfred is- How does one eliminate the unwanted things in an image like this?
    By not shooting through a chain link fence.

    Long focal lengths, getting right up to the wire and wide apertures reduce the impact, but it is never totally eliminated. If the front of lens is small enough to poke through the fence, you won't have this issue at all.

    The problem with a lot of zoos is that they have two degrees of separation of the animals from us humans. Often there is a bit of an offset from where the observer stands to the fence, especially in the case of animals that are viewed as dangerous.

  8. #8
    purplehaze's Avatar
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    Re: Seeking explanations for artefacts

    Quote Originally Posted by zen View Post
    Except for those "rings," Janis, a nice shot of an great subject.
    Thanks, Zen. I shot this in part because this animal strongly resembles my dog, Stella, gone two years now. She was a rescue of unknown origins and many people who saw her run or trot were convinced she was part wolf. This image makes me sad, because it is all too easy to imagine that this animal dreams of roaming free. I feel very ambivalent about zoos.

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