Rolling Shutter Effect Demonstrated

Discussion in 'Photography Techniques' started by KillRamsey, Jun 26, 2015.

  1. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    I got curious, tried something out, and it worked. I was wondering if panning with a moving object and forcing the use of the electronic shutter on the XT would give me a slanted background but a vertical subject, and it did indeed. If there's anyone not familiar with "rolling shutter," I'll try to define it quickly:

    When a camera uses the electronic shutter, what it's doing is reading out the pixels from the top left to the bottom right, scanning line by line like an old cathode ray tube TV. So if you've got fast motion (subject OR camera), the image will "lean" one direction and slant, because by the time the sensor gets to scanning the bottom pixels on the sensor, things ain't exactly where they used to be. Instead of motion blur, like you'd get on a physical shutter, you get a crisp tilt.

    So in this case, I was panning with the cyclist, and shot at 1/5000 (I think). Note the buildings leaning left, but the cyclist looking normal. He was still in the same spot during my 1/5000th of a second, start to finish, but the bottom of the buildings had moved over a few feet. :)

    18989870349_5f039555d9_c. Rolling Shutter Effect by gordopuggy, on Flickr
     
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  2. Richard

    Richard SC Top Veteran

    564
    Feb 1, 2013
    Marlow, UK
    Nice demo and explanation.

    Does it make a difference which way you pan? I'm wondering if the effect is reduced by panning 'with' the scan, or increased by panning 'against' it, if that makes sense.

    -R
     
  3. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    Great question... I assume that panning left, as I did, "stretches" the image laterally, while panning right would "compress" it. I'm not sure if the final result would look as tilted.

    My brain is also telling me, in very vague terms, that panning left has the equivalent effect of using a slightly longer focal length, whereas panning right would be like using a slightly wider lens, since you'd be getting more width into the frame... but my brain may be full of it.
     
  4. Luke

    Luke Super Moderator

    Nov 11, 2011
    Milwaukee, WI USA
    Luke
    and you can always fix the buildings, but then it looks like the cyclist is about to lose it.....LOL.
    18989289300_f48c63ff73_c. 18989870349_5f039555d9_b by Luke, on Flickr
     
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  5. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    Oh man that's cool.
     
  6. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    I just realized you can also see the bendy effect in his spokes, which were rotating quickly.
     
  7. Luke

    Luke Super Moderator

    Nov 11, 2011
    Milwaukee, WI USA
    Luke
    your explanation here now has me understanding what I was seeing in one of Bill's shots (59) in his Le Mans post over at the Fuji site.
     
  8. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    Yep. And 41 has a little of it too. Neat stuff.
     
  9. Richard

    Richard SC Top Veteran

    564
    Feb 1, 2013
    Marlow, UK
    I've been thinking about this since my last question. I think the effect of panning with or against the scan will be to stretch and compress objects within the picture respectively (horizontally in this case). The direction in which vertical elements lean will reverse too.

    -R
     
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  10. Lightmancer

    Lightmancer Super Moderator

    Aug 13, 2011
    Sunny Frimley
    Bill Palmer
    I have worse... Hang on and I'll show you...
     
  11. Lightmancer

    Lightmancer Super Moderator

    Aug 13, 2011
    Sunny Frimley
    Bill Palmer
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  12. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    Whoa! Laaaaaaid back.
     
  13. drd1135

    drd1135 SC Hall of Famer

    Jul 13, 2011
    Southwest Virginia
    Steve
    That's a great example, Bill. Oddly, that's exactly how many US custom shops would modify that car.
     
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  14. serhan

    serhan SC All-Pro

    May 7, 2011
    NYC
    GM1/GM5 uses 12b with e-shutter, so the rolling shutter is min compared to gx7, etc. However you loose 1/2 stop dynamic range w/ 12b.

    original.
     
  15. KillRamsey

    KillRamsey SC Hall of Famer

    Jun 20, 2012
    Cambridge, MA
    Kyle
    VERY cool shot!