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Can anyone help me??

  • 20-07-2009 10:46am
    #1
    Crispin
    Closed Accounts Posts: 523 ✭✭✭


    I am getting purple fringing on some of my long exposure shots over 1 minute long. Went out last night to do some night stuff, and I was getting purple corners on the left side of my image. I am using a sigma 10-20 at f8 for 1-2 mins. Any idea what is causing this?

    thanks in advance......


Comments

  • #2
    melekalikimaka
    Moderators, Education Moderators, Music Moderators Posts: 10,686 Mod ✭✭✭✭melekalikimaka


    my guess... chromatic abberation.

    ps can fix it under lens correction, as can lightroom


  • #3
    Dragan
    Closed Accounts Posts: 13,497 ✭✭✭✭Dragan


    Amp noise?

    http://www.flickr.com/groups/longexposure/discuss/72157606999754956/


  • #4
    Fajitas!
    Registered Users, Registered Users 2 Posts: 16,624 ✭✭✭✭Fajitas!


    melekalikimaka wrote: »
    my guess... chromatic abberation.

    ps can fix it under lens correction, as can lightroom

    Er. No. I highly doubt it.

    http://en.wikipedia.org/wiki/Chromatic_aberration

    :)

    Crispin, can you pop up a few examples? Was there any light coming from behind you? Is it a hazy purple tone? Is there any lens flare in the image?


  • #5
    Crispin
    Closed Accounts Posts: 523 ✭✭✭Crispin


    thanks guys, I actually (stupidly) don't have the images anymore, let me do it again tonight and i will post them up. I was photographing the ISS, there were a few street lights behind me and one in front. and a car passed behind me during the exposure. Not sure if that info will make it any clearer. thanks again in advance.


  • #6
    Tallon
    Closed Accounts Posts: 22,565 ✭✭✭✭Tallon


    Fajitas! wrote: »
    Er. No. I highly doubt it.

    http://en.wikipedia.org/wiki/Chromatic_aberration

    :)

    Crispin, can you pop up a few examples? Was there any light coming from behind you? Is it a hazy purple tone? Is there any lens flare in the image?
    The term "purple fringing" is commonly used in photography, although not all purple fringing can be attributed to chromatic aberration.

    ?


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  • #7
    Crispin
    Closed Accounts Posts: 523 ✭✭✭Crispin


    6B7737BF09BD45328501BDB385D0B4C8-800.jpg

    there was another street light in front of me to the right, and some behind + lights from a block of flats 100yrds away behind me. + a car drove behind me (left to right as you look at the image).


  • #8
    Crispin
    Closed Accounts Posts: 523 ✭✭✭Crispin


    Dragan wrote: »
    Amp noise?

    http://www.flickr.com/groups/longexposure/discuss/72157606999754956/

    If thats the case Dragan, I finally have a legitimate reason for a camera upgrade!!!!! :D


  • #9
    Fajitas!
    Registered Users, Registered Users 2 Posts: 16,624 ✭✭✭✭Fajitas!


    Tallon wrote: »
    ?

    Fringing wouldn't happen "in the left corners" it'd happen in areas of focus, contrast, etc.

    What you have above there, looks like light coming in, and it could be coming in through the viewfinder. If you're trying it again tonight, cover the viewfinder while you're exposing - Some cameras have an attachment on the strap for this, otherwise bring along some electrical tape for it, just to see. :)

    Other than that, it's as Dragan described :)


  • #10
    Crispin
    Closed Accounts Posts: 523 ✭✭✭Crispin


    Fajitas! wrote: »
    Fringing wouldn't happen "in the left corners" it'd happen in areas of focus, contrast, etc.

    What you have above there, looks like light coming in, and it could be coming in through the viewfinder. If you're trying it again tonight, cover the viewfinder while you're exposing - Some cameras have an attachment on the strap for this, otherwise bring along some electrical tape for it, just to see. :)

    I also had my phone out as a timer, probably didn't help. I'll bring the gaffer tape so and count 2 minutes in my head! :)


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