E-M5 and low iso noise with long exposures.

Discussion in 'Olympus Cameras' started by WeaselWily, Oct 9, 2014.

  1. WeaselWily

    WeaselWily Mu-43 Regular

    29
    Oct 9, 2014
    Jyväskylä, Finland
    Hello,

    I recently bought E-M5 with a grip and 12-40/2.8 and have been using it for a while now as travel camera. Last summer I visited Cyprus and took a few long exposure photos with E-M5 attached to a gorillapod. The resulting images were surprinsingly noisy even at the lowest base iso. I'm wondering if my copy of the camera has some sort of defect or if it's supposed to be like this.

    One example of the color noise can be found from here http://vkphoto.sunlevy.com/forum/base-iso-kohina-1.jpg. You can find the color noise by looking at the sky.

    This seemed to only affect exposure times over 10 seconds and not anything below that. The temperature outside was somewhere around 25 to 30 degrees celcius. What do you think?

    Thank you in advance!
     
  2. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi,

    If the E-M5 has a setting called NOISE REDUCTION, set it to Auto. This enables 'Dark Frame Subtraction' for shots over 1 second.

    Also make sure you have the 'noise filter' setting enabled.

    If you are looking at the RAW/ORF files, the above settings will have no effect; they only affect the JPEGs.

    Barry
     
  3. WeaselWily

    WeaselWily Mu-43 Regular

    29
    Oct 9, 2014
    Jyväskylä, Finland
    I like to shoot raw :/

    This can be fixed with a little work in Lightroom but it would be nice to get rid of it in camera.
     
  4. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    If you're using RAW, you can put the lens cap on and shoot a couple of dark frames yourself in between your shots.

    Then, you can use the dark frames in post-processing to map out some of the noise.
    I don't know if Lightroom can do it, but there are some free progams that can, iirc.

    Barry
     
  5. RDM

    RDM Mu-43 All-Pro

    I have never heard of that possibility .. that's cool.. Do you remember the name of any program that can ?
     
  6. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
  7. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    Dark frame subtraction does work with RAWs from the camera, the other noise filter settings do not of course but most RAW converters can do at least as good a job.
     
  8. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi, when I took pics of the lunar eclipse last spring, the dark frame setting did not affect the RAW files at all on my e-m1.

    Barry
     
  9. Nam-in-Sonoma

    Nam-in-Sonoma Mu-43 Veteran

    437
    Aug 23, 2012
    Penngrove, CA
    Nam
    On the E-M5 the black frame subtraction is also apply on the RAW file.
     
    • Like Like x 1
  10. christofp

    christofp Mu-43 Regular

    138
    Jul 21, 2012
    Yes, as I have done it many times:

    - pixel mapping,
    - shading compensation
    - and darkframe subtraction

    are applied to the RAW file. Both, EM1 and EM5 do it.

    All other settings are JPG only.


    While pixel mapping and darkframe are quite useful, especially with my EM1 which has more long exposure issues, the shading compensation can give very ugly results in night shots.
    If you see an ugly noise vignette/frame around your night shot, try the same shot with shading compensation=off.


    Christof
     
  11. wjiang

    wjiang Mu-43 Hall of Famer

    Dark frame subtraction ('Noise Reduction') is only engaged in AUTO for exposures longer than 4 seconds. If you want it on for shorter exposures you have to force it to ON. Nice thing is that it's applied to RAWs, so if you're lazy (like me) you don't have to take a separate dark frame and apply it in post.

    'Noise Filter', on the other hand, is just a normal smoothing noise filter that gets applied to JPEGs, so if you shoot RAW it's not much use.
     
  12. Wisertime

    Wisertime Mu-43 All-Pro

    Aug 6, 2013
    Philly
    Steve
    I've done noise reduction (dark frame subtraction) in Raw with the 12-50 at ISO 100 and get very clean files...12-40 should be even slightly better.