Banding issues at low ISOs with E-M5

Discussion in 'Olympus Cameras' started by ecw, Oct 8, 2014.

  1. ecw

    ecw New to Mu-43

    3
    Oct 8, 2014
    I have heard of high iso banding issues, and banding issues with the 20mm lens, but my problem seems to be different.

    Im getting banding between ISO 200-500. At ISO 800+, there is no banding. The light source doesn't seem to matter, as the same problems occur in daylight.

    Has anyone else experienced this? I'm thinking its a defect with my camera.

    I did a simple test, taking the same photo with different ISOs:
    All taken with the 25mm f/1.8

    (full album here: https://www.flickr.com/photos/127648879@N03/sets/72157648146029478/ )

    20141008-PA080088.jpg by ecw11, on Flickr

    20141008-PA080089.jpg by ecw11, on Flickr

    20141008-PA080090.jpg by ecw11, on Flickr

    20141008-PA080091.jpg by ecw11, on Flickr

    20141008-PA080093.jpg by ecw11, on Flickr

    20141008-PA080095.jpg by ecw11, on Flickr

    20141008-PA080097.jpg by ecw11, on Flickr
     
  2. HarryS

    HarryS Mu-43 Top Veteran

    919
    Jun 23, 2012
    Midwest, USA
    Agreed. Looks like defect. Are these JPG out of camera?
     
  3. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    what it reminds me of is an unstable voltage on the amplifier/reset circuits, it switches up each full stop of ISO on the amp (which is why noise doesn't increase as much by increasing ISO if you reach the next full stop (320 to 400 or 640 to 800) for example (which is why it's almost never worth using third stops of ISO, they are essentially the lower stop digitally pushed rather than an analogue gain (unless the E-M5 has changed since the E-520/E-3/E-5, I don't actually know if it's changed for the newer bodies).

    At 800 it might shift to a different power supply which has better smoothing thus removing the jitter between lines (as each line is read one at a time). If you remember earlier bodies would get heavy banding - this was partially as you need to keep the charge voltage consistent because small changes result in large differences after amplification, a change in voltage might not drain the pixel or might over amp it once drained, etc.

    Really though, this is all just guesswork - I have no clue of the inner design of the sensor and I'm just guessing on the vague design behind CMOS sensors that I can remember, I would guess it's to do with the power supply to the discharge(read) or amplification stage though. Does it change on a fully charged battery vs an empty one?
     
  4. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    That certainly isn't right. And disappearing at ISO800 is strange.

    Are these shot RAW or out of camera JPEGs? And if RAW any adjustments to the shadows or just a straight "default" kind of conversion?

    I've pushed ISO200 shadows by quite a bit (shooting RAW) and never seen banding like this on my E-M5.
     
  5. fortwodriver

    fortwodriver Mu-43 Top Veteran

    959
    Nov 15, 2013
    Toronto, Ontario, Canada
    Frank
    Have you got a really noisy power transformer nearby? Anything that uses a "wall wart" or power cube? Does it look better or worse in different rooms of the house?
     
  6. ecw

    ecw New to Mu-43

    3
    Oct 8, 2014
    These were all jpgs, but the same thing happens with the raw files.

    I don't think its caused by interference from another source, as this still happens when i'm hiking in the middle of no where.
     
  7. HarryS

    HarryS Mu-43 Top Veteran

    919
    Jun 23, 2012
    Midwest, USA
    Whatever the cause, it needs fixing, Can't shoot above ISO 800 all the time. Is the camera still under warranty?
     
  8. ecw

    ecw New to Mu-43

    3
    Oct 8, 2014
    Luckily, its still under olympus's warranty and I have adorama's extended warranty
     
  9. Reflector

    Reflector Mu-43 Veteran

    406
    Aug 31, 2013
    http://home.comcast.net/~nikond70/Charts/RN_e.htm#D3S_14,OM-D E-M5_12

    For the E-M5 that occurs around ISO 400. I left the D3s in the chart for the enjoyment of anyone else who wants to see the multiple stages that occur at higher ISOs.
     
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  10. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Yeap, the plot sort of shows what I meant (less so for the lower ISOs). If you look at 1600 the ones after it are flat, then the same for 3200 and 6400... it actually looks like they're pulling the higher stop rather than pushing the lower stop now though which is interesting.

    It's fun to look at how a few different brands do it though, thanks for the link.
    Edit: The following link is a perfect example of what I meant, it's almost an ideal graph to show it. http://home.comcast.net/~nikond70/Charts/RN_e.htm#EOS 5D Mark III_14
     
  11. fortwodriver

    fortwodriver Mu-43 Top Veteran

    959
    Nov 15, 2013
    Toronto, Ontario, Canada
    Frank
    Just out of curiosity. What brand/model SD card are you using?
    The banding on these images is very tight... It doesn't look like channel-read noise to me.
     
  12. klee

    klee Mu-43 Veteran

    367
    Mar 20, 2013
    Houston, TX
    Kevin
    pretty much happens to every one with an EM5+20mm combo. I don't think anyone has successfully gotten around this, including Olympus or Panasonic.

    does anybody get this with an EM1 or EM10 body? I really miss the 20mm. amazing glass. terrible AF on the EM5.
     
  13. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    He's getting it on the 25mm.

    Barry