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GX-7 Weird Pictures with Electronic Shutter

Discussion in 'Panasonic Cameras' started by Drdave944, Oct 6, 2014.

  1. Drdave944

    Drdave944 Mu-43 Top Veteran

    698
    Feb 2, 2012
    I was fiddling around with my Panny GX-7 on the way home from the beach with my wife driving. I was shooting pictures out the side window with my 75mm lens. The camera happened to be on E shutter. I noticed the pictures looked weird.We were going about 45 miles per hour and speed was 1/400 to 1/1000 sec
    When using the E shutter(silent mode ) Close up pictures show a pronounced slant to vertical objects. This is especially true of up close objects. When I switched to mechanical shutter this did not happen. Does anyone know the reason for this?
    See examples. Beach-15. Beach-16.




    Picture with slant is with E shutter
     
  2. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    E-shutter may expose all the pixels for 1/1000th of a second however the travel time across the sensor is still only 1/25th of a second, thus if something is moving across the frame as the "shutter" travels down it it will appear in the position that it was exposed at when the shutter passed causing a slant.

    The mechanical shutter moves much faster, thus less slant(however it's still present, just smaller).
     
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  3. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
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  4. wushumr2

    wushumr2 Mu-43 Regular

    137
    May 20, 2013
    Exactly. I think back in the CCD era you didn't have much problem with that because CCDs can read data off the sensor very quickly (well not sure with really high-MP sensors because there's an extra A/D conversion step compared to CMOS I believe) but CMOS sensors take much longer.
     
  5. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Search is your friend. The shortcomings of electronic shutters in general have been discussed thoroughly here. Your first picture is a particularly good illustration of the problem.

    Other than one or two test shots, I have never used the electronic shutter feature on my GX7s. I have never needed the absolute silence and, other than for that, I see no reason to use it.
     
  6. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Interesting. Another benefit of the e-shutter is no chance of shutter shock, which has historically (and continues to be) a noticeable problem with many/most mirrorless cameras, especially with image stabilization (both optical and IBIS) comes into play. It seems to me that unless you're shooting fast action there's almost no reason not to use the electronic shutter.
     
  7. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    That's a reasonable statement for GX7 and earlier electronic shutter implementations.

    For the GH4, GM1 and GM5 things are a bit different. The shutter readout is faster, which means slightly less rolling shutter artifacts - a good thing. The downside is the sensor has lower dynamic range when using the electronic shutter on these cameras - the data is only 10-bit and so shadows pushed at base ISO have more noise than when using the mechanical shutter. At higher ISO this is a non-issue, the sensor is already noisier in the shadows anyway and 10-bits is plenty. That works well for concert shooters using the electronic shutter for quietness since they will be at high ISO most likely anyway in the dim lighting.

    But for a landscape shooter trying to avoid shutter shock it is a trade off - you lose some DR by using the electronic shutter on the GH4, GM1, GM5. With the earlier cameras with the slower read out their was no impact to DR so a landscape shooter could get no shutter shock and full DR.
     
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  8. WT21

    WT21 Mu-43 Hall of Famer

    Feb 19, 2010
    Boston
    I use eShutter for quiet shooting (my teenagers don't like their pics taken, so I do stealth!) and to reduce shutter shock at low shutter speeds -- of static subjects.

    It would be magical if it didn't have rolling shutter, but even as-is, it can be useful.
     
  9. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    Well not really. In CCD days the thing was the sensors were incredibly low resolution more than anything. Not many rows to read. And very few CCD sensors ever did rolling read out for stills, just video cameras did rolling shutters. Essentially all CCD based still cameras had a mechanical shutter so we never had the opportunity to see the problem.

    Modern CMOS sensors can actually have much faster read outs than CCD sensors, hence the very high frame rates despite massively increased resolution compared to CCD cameras of a decade ago. In CCD the ADC has to be off chip and so to go fast you have to have multiple analog read out lanes coming off chip. This is a huge problem for both noise and power consumption. Not to mention extremely annoying bias/gain matching (one of the old fast Nikons had this problem and resulted in bad banding at high ISO). For awhile CMOS sensors did essentially the same thing, but these days almost CMOS sensors all have ADCs on chip. In fact most have one ADC per row. These ADCs are slower than the original off chip ones (which allows for lower read noise because the sample and hold circuitry can have a lower analog bandwidth) but since there are 4000 of them as opposed to one or two the end result is much faster read times for the entire array. It is essentially a massively parallel operation compared to CCD implementations.
     
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  10. Drdave944

    Drdave944 Mu-43 Top Veteran

    698
    Feb 2, 2012
    I was doing macros of flowers. I don't look at this behavior as a shortcoming but as another cool feature for trick photography. I am going to take some pictures of cars going by.
     
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  11. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Andrew Lossing
    The conditions you describe are virtually perfect for seeing rolling shutter. Couldn't have asked for a better scenario for it to occur.
     
  12. scott2hot

    scott2hot Mu-43 Veteran

    318
    Aug 27, 2012
    west yorkshire
    scott
    Yep..i lost many great looking pics of my little girl in park ,forgot i had it in electronic shutter and burst...got some weird quasimodo face shots of my daughter on fast moving swing...only one out of approx 20 shots came out ok-ish
    deleted all the distorted ones!..i for one wont use the feature again...just something else to remember..when changing settings on the fly.
     
  13. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    It is certainly very useful, and an opportunity for some creative image-making. But it is good to understand how and why it happens, so you control it and get no unwelcome surprises.
     
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