Could someone please explain this phenomenon?

Discussion in 'Digital Photography' started by G5Unit, Feb 8, 2012.

  1. G5Unit macrumors 68020

    G5Unit

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    #1
    About a year ago, I used an Epson Perfection 1250 scanner to capture a strip of color changing LED lights from about 2 feet away. What I got was the uploaded image.

    I recently tried to re-create the effect with an Epson Perfection 1600, yet I was unable to get the streaks of light that I achieved in the original.

    What was going on in the original scan to make it come out like it did?
     

    Attached Files:

  2. robbieduncan Moderator emeritus

    robbieduncan

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  3. macuserx86 macrumors 6502a

    macuserx86

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  4. G5Unit thread starter macrumors 68020

    G5Unit

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    #4
    I made sure that the top of the glass on the scanner was as clean as possible, yet there was a lot of dust underneath.
     
  5. jackrv macrumors 6502

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    Jul 14, 2011
    #5
    I agree with Robbie. Looks like a longer exposure.
     
  6. Nostromo macrumors 65816

    Nostromo

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  7. psonice macrumors 6502a

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    #7
    It's caused by the way the scanner works. A scanner is a bit like a camera - it has a sensor to record the image, and a lens (or mirror) combination to focus the image. The difference though is that the sensor records a single line instead of a whole scene like a camera does, so it has to 'scan' down the page taking lots of one-line images as it scans the page.

    If you hold something far away from the scanner, it's effectively 'out of focus'. On a camera a point of light (like the lights you were holding) turns into a blurry circle when it's out of focus, but the optics in a scanner are different - quite often they focus in a single direction, meaning when it's out of focus you get a line. This is what you captured.

    It's actually possible to make a super-high-res camera (like 100 megapixels or more!) from a scanner. You take the sensor out of it, and attach it to a camera lens to focus the light. Then you mount the whole thing on a device that slowly rotates it while it's 'scanning', and it scans the scene.

    Links for the curious:

    http://hackaday.com/2009/06/09/130-megapixel-scanner-camera/
    http://golembewski.awardspace.com/
     

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