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Why does Lightning create Bright Bands on a Camera?

  1. Aug 11, 2016 #1
    I tried taking a photo of lightning with my smart phone.

    As the lightning flashed across the sky, bright horizontal bands of light flashed across the screen.

    What's the cause of this?
     
  2. jcsd
  3. Aug 12, 2016 #2
    I'm not an expert but the CCD camera uses lines of pixels and when a pixel is overstimulated it overflows into the rest of the pixels in the line. Hope that helps!
     
  4. Aug 12, 2016 #3

    davenn

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    no not quite ... considering most cameras these days are CMOS sensors

    I want to hear more from the OP before answering
     
  5. Aug 12, 2016 #4
    Were you just using the phone as a camera or did it have other apps running?
    If so they might have been generating a bit of random noise on the screen because of lightning interfering with the local cell phone network.
     
  6. Aug 12, 2016 #5

    davenn

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    firstly ... where you doing video ( movie mode) or photo mode ?
    show us an example if what you captured

    If video, it is caused by the shutter method used in today's modern cameras and it's a total pain in the butt for us serious storm photographers

    whilst awaiting your image, does it look anything like this one ? ....

    upload_2016-8-13_11-51-0.png

    this is just one frame out of a video. when viewing the video at normal speed all you see is a
    wide band of flickering bright light, much as the OP described


    Dave
     
    Last edited: Aug 13, 2016
  7. Aug 12, 2016 #6

    davenn

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    probably not ....
    see my post as an example, Im pretty sure this is what the OP will be referring to

    LETS WAIT for the OP to respond to my questions and confirm :smile:
    instead of wild guesses :wink:


    Dave
     
  8. Aug 12, 2016 #7

    DaveC426913

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    It took me several looks to realize what you're referring us to.

    The top fifth of the image is blocked out.
     
  9. Aug 13, 2016 #8

    davenn

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    and the lower 1/3 is excessively darkened. because of the shutter

    This is the effect caused by the rolling shutter system used with CMOS sensor cameras .... tis extremely frustrating
    Cameras with CCD chips ( there are very few left unfortunately) use a global shutter. The difference is that the CCD
    imaging system using the "global shutter" system where the signal from the whole chip is switched on and off. rather than just a scrolling band of exposed sensor.

    As a result, I'm still using an 8 year old CCD chipped camera with horrible low resolution. Unfortunately, there is
    nothing more modern that I can replace it with


    Dave
     
  10. Aug 14, 2016 #9
    It was in video mode. My camera is a Sony Exmor RS IMX240.

    The funny thing is that I see these bright bands even if my camera is pointed away from the lightning when it strikes.
     
  11. Aug 14, 2016 #10

    DaveC426913

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    Makes sense. Lightning is bright enough to briefly light up your whole environment bright as day. And it happens very fast. So, as far as the camera is concerned, whether it is pointed at or away from the flash, it is immaterial to its inability to capture the image.
     
  12. Aug 14, 2016 #11

    davenn

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    yup, confirms my suspicion ... just say thankyou to CMOS sensors and rolling the shutter system

    there isn't anything you can do about it



    Dave
     
  13. Aug 16, 2016 #12
    Ahh, now I see.

    Some idiot told me that the bright bands were due to EMPs from the lightning interfering with the electronics. Sounds cool, but bullshit.
     
  14. Aug 18, 2016 #13

    DaveC426913

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    Lightning sure can play weird with electronic devices - radios in particular. Although that's the radio emissions, not the electronics.

    If your camera is senstive in the radio band, you could make millions off reverse-engineering it. :woot:
     
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