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G5 random noise on low light long exposures

Discussion in 'Panasonic Cameras' started by jrsilva, May 3, 2013.

  1. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    Hello,

    Before I purchased my G5, I did lot's of long exposures with my old G1.
    As expected there were a little bit of noise, but perfectly acceptable.
    Because the G5 deal better with high ISO settings, I thought that on long exposures under low light (before sunrise, for example) I would be presented with more clean photos.
    Last weekend I get up earlier and went to a spot to take a few photos of a bridge with the sun rising from behind.
    I toke several long exposure photos before the sunrise using ISO 160 and a ND400 filter to smooth the water and found that the resulting photos that I did with 60 seconds or more than 20 seconds have a strange random coloured noise.
    It is a different noise from the one we used to see on high ISO settings.
    The photos I toke with exposures of 8 or 13 seconds look nice and without any trace of that uggly noise.

    I never had this problem with my G1.
    I'm a bit shooked and disappointed, because I was expecting to get better results than the ones from my old G1.
    Is anyone having this same problem?
    Could be caused by any camera setting?
    I was using Oly 12-50mm @ 14mm, iDynamic Standard setting, iResolution Standard setting, ISO 160, aperture priority, f/5.6 to f7.1, mechanical shutter with remote shutter.
     
  2. swampduck

    swampduck Mu-43 Veteran

    334
    Mar 29, 2013
    Taneytown , MD
    Dan
    Post images so we can see what you are talking about
     
  3. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    I will post imagens as soon as I get home.
     
  4. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    Here are 2 samples.
    The first one is a 100% crop from the RAW file. Note the blue noise.
    And the second one from a JPG file (low resolution).
    Looks like the in-camera software tried to apply some noise reduction in the JPG file but did not remove the noise completely. It ended up looking like dust specs.

    This shot was taken about 10 minutes before the sun shows up.
    Camera: G5, Lens: Oly 12-50mm @ 14mm, f/7.1, ISO 160, Exposure: 60 seconds, Pattern Metering, Hoya ND400 filter, tripod

    RAW file from ACR, with default settings
    [​IMG]

    JPG file from camera
    [​IMG]
     
  5. BigOwl

    BigOwl Mu-43 Regular

    61
    May 3, 2013
    San Antonio, Texas USA
    Al
    I've never seen noise like that, but I haven't taken 60-sec. with the G5 yet. Can you show results with the shorter exposure time? That would be interesting to see.
     
  6. RnR

    RnR Mu-43 All-Pro

    Sep 25, 2011
    Brisbane, Australia
    Hasse
    Dark frame subtraction not switched on? Not sure what it is called on pana camera's.

     
  7. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    This is a photo taken a few minutes later, but with a shorter exposure time (13 seconds).
    Camera: G5, Lens: Oly 12-50mm @ 14mm, f/8, ISO 160, Exposure: 13 seconds, Pattern Metering, Aperture priority, Hoya ND400 filter, tripod

    RAW file from ACR, with default settings
    [​IMG]

    Low JPG file from camera
    [​IMG]
     
  8. BigOwl

    BigOwl Mu-43 Regular

    61
    May 3, 2013
    San Antonio, Texas USA
    Al
    Wow! That's a significant difference from the 60-sec. one. I'll try the same thing later this evening and see what I get. I haven't had the G5 very long and haven't taken exposures of that duration. Never saw it with my G1's, though. Thanks for the alert.
     
  9. BigOwl

    BigOwl Mu-43 Regular

    61
    May 3, 2013
    San Antonio, Texas USA
    Al
    I tried some 50-second exposures this evening. On extreme enlargement I saw some small flecks similar to yours in both jpeg and RAW. When I turned on the "Long exposure noise reduction" as RnR suggested, they were eliminated, but as he pointed out there is an additional 50-second processing step in the camera immediately after the exposure ends.
     
  10. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    X2 - it's called surprisingly enough "long shutter noise reduction"
     
  11. RnR

    RnR Mu-43 All-Pro

    Sep 25, 2011
    Brisbane, Australia
    Hasse
    Whoa - logical naming :eek: Its just 'Noise Reduction' on Olympus bodies, which causes all kinda of confusion at times for new folk :frown:
     
  12. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Ehud
    I suspect the the filter is causing this try shooting without.

    The picture bellow I took with 60 seconds and does not show any artifacts.


    <a href="http://www.flickr.com/photos/ehudlavon/8510299664/" title="The Dead Sea at night by Ehud Lavon, on Flickr"> 8510299664_cf622f5fcb_b. "1024" height="779" alt="The Dead Sea at night"></a>
     
  13. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    Thank's for your replies and samples.
    Well, I know about the long shutter noise reduction feature, but I've never needed to use any Noise Reduction feature on my G1 when I shoot long shutter exposures and the results were satisfactory. I don't like to have to wait the same time as the shoot for the Noise Reduction to process, plus I believe there would be some image softening and a bit of loss of detail (correct me if I'm wrong).

    Yes, I have already think of that, but without the ND filter it is impossible to shoot with 60 seconds a few minutes before (and during) the sunrise...
    Your picture looks gook, but seams that you shoot with more light conditions that me. My photos here taken with few light.
     
  14. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    The G1 and GH2/G5 sensors are completely different - why would you assume they operate the same way?

    The long shutter NR is designed specifically to eliminate exactly the "problem" you describe. I agree that waiting is problematic, but its either that or deal with the noise in post, and this type is extremely difficult to correct. Choose the lesser of the evils, or go full frame.
     
  15. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    I was not expecting worst results in low light using the G5 compared with the G1.
    I've never used Noise Reduction feature with my G1.
    That's why I asked if I'm doing something wrong.
     
  16. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    Huge advances in high ISO noise have come somewhat at the expense of low ISO noise.

    60+ second exposures are probably not a design priority.

    You dont have the right to complain about something until you at least attempt to use the built in tool available to help
     
  17. jrsilva

    jrsilva Mu-43 All-Pro

    Nov 1, 2012
    Portugal
    Jaime
    I need to do some more long exposure tests in low light
     
  18. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    I use long exposure noise reduction and have with every camera I've owned and it's not a problem Are you taking movies or making images, lol? What difference does it make if you have to wait for dark frame subtraction? If doesn't affect resolution like noise filtering so it's only drawback is a short wait.

    ALL camera sensors can exhibit this problem. Some will do it almost never, some will do it with every exposure, and some sporadically. Might as well get used to it because as the sensor wells get smaller, the problem becomes more pronounces.

    Just use long exposure noise reduction therefore.
     
  19. pcake

    pcake Mu-43 Regular

    187
    May 3, 2010
    i think noise reduction is for any noise, not particularly long exposure noise, no?

     
  20. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    No. Google "Dark Frame Subtraction" and that's what Panasonic calls "Long Exposure Noise Reduction".

    It's not filtering. It's taking two photos, one with the shutter closed, and subtracting hot pixel info derived from the dark frame from the real photo.

    Also read the "Advanced" manual that came on the CD. It covers this.