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Image strangeness. What's going on?

Discussion in 'Through-the-Lens Club' started by JellyBelly, Dec 15, 2006.

  1. JellyBelly

    JellyBelly Meat Popsicle

    1,098
    0
    Mar 1, 2005
    Estados Unidos
    [​IMG]

    What's the deal with that bullseye in the middle of the picture? I went to shoot the northern lights and all of my images have that mess in them to some degree or another.

    I used the XTi's kit lens and a really good Canon 24-70 lens and it happened in both. I was shooting RAW, at a few different ISO levels, f-stops, and exposures and it occurred in every one.

    It's well above freezing outside so I don't think it's the cold.

    What gives?
     
  2. hwyhobo

    hwyhobo

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    Jun 3, 2003
    Silicon Valley
    Where in the world are you located? :shocked:

    As for the thingie in the middle, it kinda looks to me like a processing artifact. Sometimes you may get similar patterns from overly aggressive application of median filter. Perhaps something similar is happening during conversion?
     


  3. Fred

    Fred Millennium Member Lifetime Member

    2,031
    5
    Dec 17, 1998
    CA
    I don't have a clue what it is, but if it keeps doing it, at least you can make some targets! :tongueout:
     
  4. JellyBelly

    JellyBelly Meat Popsicle

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    Mar 1, 2005
    Estados Unidos
    Michigan. There was an abnormally large solar flare a couple days ago that made the news so I knew ahead of time that we'd be getting northern light activity.

    I couldn't pass up the opportunity to take pictures. Only once before last night had I ever seen the Aurora Borealis, and it was never this intense.
     
  5. hwyhobo

    hwyhobo

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    Jun 3, 2003
    Silicon Valley
    So it is a processing artifact. Cool. JellyBelly, what was your process?
     
  6. JellyBelly

    JellyBelly Meat Popsicle

    1,098
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    Mar 1, 2005
    Estados Unidos
    I was using a plain-Jane 2GB SanDisk CF card.

    File Name IMG_2808.CR2
    Camera Model Canon EOS DIGITAL REBEL XTi
    Shooting Date/Time 12/14/2006
    Shooting Mode Program AE
    Tv( Shutter Speed ) 30
    Av( Aperture Value ) 2.8
    Metering Mode Evaluative Metering
    Exposure Compensation +1 1/3
    ISO Speed 400
    Lens EF24-70mm f/2.8L USM
    Focal Length 24.0 mm
    Image Size 3888x2592
    Image Quality RAW
    Flash Off
    White Balance Mode Auto
    AF Mode Manual focusing
    Picture Style Landscape
    Sharpness 4
    Contrast 0
    Saturation 0
    Color tone 0
    Color Space sRGB
    Noise Reduction Off
    File Size 8650 KB
    Custom Function C.Fn:01-0
    C.Fn:02-0
    C.Fn:03-0
    C.Fn:04-0
    C.Fn:05-0
    C.Fn:06-0
    C.Fn:07-0
    C.Fn:08-0
    C.Fn:09-0
    C.Fn:10-0
    C.Fn:11-0
    Drive Mode Single-frame shooting
    Owner's Name **************
    Camera Body No. **************
     
  7. hwyhobo

    hwyhobo

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    Jun 3, 2003
    Silicon Valley
    And then what happened? How did you convert it, how did you post-process it?
     
  8. He said he used RAW, but he posted a JPG, therefore there is some processing going on. Put the RAW file on www.putfile.com and provide us a link to the original to see the RAW file which is what, a BMP (bit map)?
     
  9. nipperwolf

    nipperwolf

    3,072
    28
    Oct 3, 2002
    no, that would be a RAW......heeelllooooo;)


    :supergrin:
     
  10. JellyBelly

    JellyBelly Meat Popsicle

    1,098
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    Mar 1, 2005
    Estados Unidos
    The bullseye pattern was visible on the camera's LCD monitor when I reviewed the image after taking the shot (before downloading the image into the computer).
     
  11. sjfrellc

    sjfrellc CLM

    720
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    Dec 26, 2004
    Novi, Michigan
    My theory is that because it is central and circular it is the lens filter causing artifact. You would think its not aberration in the lens.


    Since there is no repeating pattern in the subject, that rules out moire effect.
     
  12. Thanks.

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


     
  13. Hokie

    Hokie NRA Member

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    May 16, 2006
    VA
    The image on the LCD is not the RAW file. The file has a small JPEG in it for display on the LCD.

    Has it happen in any shots you taken since these?
     
  14. hwyhobo

    hwyhobo

    1,426
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    Jun 3, 2003
    Silicon Valley
    I think his point was that since it is RAW, it cannot be displayed directly in the browser, it would have to be processed first. However, you are right that a RAW file could be posted for download. If one had Adobe ACR (for example), one could then open it on his own computer.
     
  15. DTQ

    DTQ c8h10n4o2 me

    Put the RAW on an FTP or somewhere we can download it and let us take a look at it in ACR.
     
  16. JellyBelly

    JellyBelly Meat Popsicle

    1,098
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    Mar 1, 2005
    Estados Unidos
    I don't know how to post the RAW image here, but in Canon's software the irregularity shows up on my monitor in all the images.

    I took almost 400 pictures today inside a museum with the exact same equipment and the bullseye didn't appear. Maybe my camera is haunted!:shocked:
     
  17. DTQ

    DTQ c8h10n4o2 me

    email one to me, send a GT message and I'll give you my email.
     
  18. JellyBelly

    JellyBelly Meat Popsicle

    1,098
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    Mar 1, 2005
    Estados Unidos
    My interweb service doesn't allow it's customers to attach anyting but .gif and .jpg files to our E-mails. I couldn't send one if I wanted to.