IBIS and UWA

Discussion in 'Native Lenses' started by wbuzatto, Aug 7, 2016.

  1. wbuzatto

    wbuzatto Mu-43 Regular

    55
    Nov 17, 2011
    Campinas, SP - Brazil
    Walmyr T. Buzatto
    Visited the Air and Space Museum in Le Bourget, Paris, yesterday evening, and shot this picture hand-held with my E-M1 and Oly 7-14/2.8. 6-second exposure, ISO 1000, wide open and at 7mm focal distance. What does it say about IBIS? The trail above the 747 depicts the International Space Station in its pass above Paris shortly before 11pm on Saturday, August 06, 2016.

    P8060024.
     
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  2. drd1135

    drd1135 Zen Snapshooter

    Mar 17, 2011
    Southwest Virginia
    Steve
    That's impressive. It's funny how there seems to be some motion blur at the edges but not everywhere.
     
  3. wbuzatto

    wbuzatto Mu-43 Regular

    55
    Nov 17, 2011
    Campinas, SP - Brazil
    Walmyr T. Buzatto
    Indeed! It's obvious that the people are blurred at the bottom, as they were moving around, but the top right (the rocket) is blurred as well, just not as much as the people.
     
  4. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    Most likely rotation blur (roll axis).

    Pitch and yaw blur vary with focal length so shooting UWA means you can get away with more pitch/yaw error and thus can shoot longer exposures as the focal length goes down. Pitch/Yaw blur is also uniform across the field, same in the corners as in the center.

    Roll axis blur is the same regardless of focal length and is always worse at the edges than at the center. So shooting UWA has just as much sensitivity to roll axis motion as super-telephoto does. Thus in this shot where UWA has allowed for extreme insensitivity to pitch/yaw blur we are now seeing the exposure limited by roll axis blur.

    Worth noting that OIS systems can not compensate for roll axis blur at all - and for telephoto lenses that is just fine since pitch/yaw is a far, far larger problem than roll axis. And many early IBIS systems didn't either, again because pitch/yaw is the major problem for "normal" shutter speeds. But 3 and 5 axis IBIS can tackle roll axis motion - up to a point.
     
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  5. wbuzatto

    wbuzatto Mu-43 Regular

    55
    Nov 17, 2011
    Campinas, SP - Brazil
    Walmyr T. Buzatto
    Perfect explanation, @kwalsh@kwalsh. Thanks! I didn't think about OIS not being able to compensate for roll axis blur, but sensor-shift does!
     
  6. drd1135

    drd1135 Zen Snapshooter

    Mar 17, 2011
    Southwest Virginia
    Steve
    I did wonder about roll but I couldn't quite see it. The best example was the red wingtip on the right with the inward side looking sharper. A hand-held six second exposure is crazy.
     
  7. wbuzatto

    wbuzatto Mu-43 Regular

    55
    Nov 17, 2011
    Campinas, SP - Brazil
    Walmyr T. Buzatto
    This one was shot with same 1000 ISO, but closed down to F/6.3 and 5s exposure, hand-held as well. Much less blur, just underexposed.

    P8060025.
     
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