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GX80 long exposure noise

Discussion in 'Panasonic Cameras' started by FernandoBatista, Oct 8, 2016.

  1. FernandoBatista

    FernandoBatista Mu-43 Regular

    43
    Sep 3, 2012
    Portugal
    Anyone tried long exposures with the GX80?

    How is it comparing with a GX7? or an EM10?

    I've used both the GX7 and EM10 in the past, and while on regular shots they were similar in noise, in long exposures the EM10 was much better, the GX7 showed quite a bit of noise or hot pixels.

    I'm considering getting back to m4/3 with a GX80 now and I'd like to know from those who used one for long exposures.

    Thanks.


    Regards,
    Fernando
     
  2. sdb123

    sdb123 Mu-43 Veteran

    249
    Jul 25, 2014
    Northants, UK
    Steve
    Hi Fernando...just to let you know there is a typo in your title, G80 not GX80. :)
     
  3. FernandoBatista

    FernandoBatista Mu-43 Regular

    43
    Sep 3, 2012
    Portugal
  4. sdb123

    sdb123 Mu-43 Veteran

    249
    Jul 25, 2014
    Northants, UK
    Steve
  5. FernandoBatista

    FernandoBatista Mu-43 Regular

    43
    Sep 3, 2012
    Portugal
    Errrr....upps... sorry :D

    Can't correct the title, can I?
     
  6. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi, you should be able to see an Edit Thread link under Thread Tools above the first post.
     
  7. Machi

    Machi Mu-43 Veteran

    208
    May 23, 2015
    Unfortunately the GX80 has the same problem with long exposure noise (dark noise) as the GX7 or E-M1.
    That's why it's limited in the Bulb mode to just 2 minutes (EM10 has 30 min limit).
     
  8. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    Any camera will show this type of noise which is why you have the long exposure NR. I had the opportunity to use a D800 and it's no different. The longer the exposure , the more prominent each pixels output will be.
     
  9. Levster

    Levster Mu-43 Top Veteran

    Without using Long Exposure NR the output from the 16MP Sony sensor cameras are the best performers. When you use long exposure NR the camera takes a second shot straight after the first exposure, but the second shot is not exposed to light. The second shot will only contain the electrical noise generated by the camera, and when doing Astro shots these are called Dark frames. In the tests that I've done the E-P5 produced the cleanest dark frames out of the mu43 cameras that I've tested. For reference the GM5 produced worst; there were a kaleidoscope of greens, blues and reds. The mu43 camera that I would recommend for long exposure work is the E-M10 II, because this has the good sensor and has the enhanced boost setting to help focus. I'm led to believe that the GX8 performs the best out of LUMIX cameras.
     
    Last edited: Oct 18, 2016
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  10. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Yes, from what I have seen the GX8 has excellent long exposure noise characteristics, among the best in the system. Likely this is because it uses a Sony sensor. Long exposure noise seems to be a strength of Sony sensors, and a weakness of Panasonic sensors.

    It's actually one of the strikes against the G85 for me, which otherwise seems like it will be an exceptionally good, well-rounded camera. It may push me towards the E-M1 II, which is honestly more camera than I need.

    Then again, I'm probably better off just getting the G85 and the Laowa 7.5mm/f2 to use instead of my 7.5mm/f3.5 fisheye. The long-exposure noise on the E-M1 II will surely be better, but not 1.5 stops better!
     
  11. Levster

    Levster Mu-43 Top Veteran

    This shot is a crop from a frame taken on my GX80, with the exposure settings of 50s/ISO800:

    P1010210-1-2.

    All the little dots are hot pixels or other noise that would likely mask the actual signal that you're trying to capture.
     
  12. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    While the hot pixels are one thing, I found that the more disturbing issue with my GX7 when taking long / high ISO exposures is the dense purple haze which starts to creep in from the corners / edges of the frame. Dark current noise, I guess it is? Taking dark frames and / or in-camera noise reduction do a lot to help it, but it's an annoying workflow issue.
     
  13. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    Any noise present in the black frame will be subtracted from the actual photo, so the end result should be the same. Last year I did some informal testing just to satisfy my curiosity. I used three GH4's belonging to some friends of mine. I used 1 minute exposures. Each was tested indoors at about 70 degrees F. The test was repeated after allowing the cameras too sit outdoors for 30 minutes, just above freezing. Indoors, all three showed different levels of colored noise. Outdoors each camera's visible noise decreased. With each subsequent exposure, the noise increased slightly, likely due to the sensor heating up. Older 3 chip broadcast cameras frequently used Peltier cooling devices to cool the image sensors, thereby decreasing the visible noise. GH4's as I recall also use the Sony sensor. It shows that this performance varies from camera to camera, and temperature definitely has some effect on the end result.
     
  14. Levster

    Levster Mu-43 Top Veteran

    I found the exact same thing with the GM5. I could only test up 60s today because that's how high the manual exposure goes. I do have a remote release kicking about so I'll try a 2 min exposure and see what happens.
     
  15. Levster

    Levster Mu-43 Top Veteran

    For astro shots you ideally don't want any noise though. The end result between, for example, a GM5 astro shot and a E-M10 astro shot would show a much more detailed image from the E-M10, due to the E-M10 picking up less artificial signal from the camera. I did use to have a whole bunch of dark frames at different exposures for different cameras but ditched them all in a cleanup a while back. There was a marked difference between the cameras taken at roughly the same temperature (cold UK winter).
     
  16. sachinwfs

    sachinwfs New to Mu-43

    2
    Oct 13, 2016
    How did you manage to take a dark frame image? When I attempted to shoot with the lens cap on in M—even in shutter priority—the camera refused to fire. Instead, it just lit up a "Low" symbol.

    Are these hot pixels transient or permanent? If permanent, I can imagine that you could create a dark frame for each camera you have and use them to reduce noise in your final images?
     
  17. Levster

    Levster Mu-43 Top Veteran

    I just put the camera into M mode, select manual focus (which I think is your issue) and then select the exposure/iso/aperture required.

    In the astro guides that I've read you combine 20 or so dark frames using software like Deepstacker. This would then get rid of the transient noise, assuming that it's random, leaving only the hot pixels in the combined image.
     
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