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GX8 long exposure noise performance.

Discussion in 'Panasonic Cameras' started by tg9413, Aug 5, 2016.

  1. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Hey guys,
    I've done some reading of my own, and the review seems mixed, some said it is bad due to the higher pixel density, some said it is actually better for long exposure without NR that's why it can supports much longer bulb mode than GX7. And to be honest, most of those forum post end up in a hot mess debate on FF vs APSC vs M43.
    So I am wondering if anyone here has any experience with GX8 on the long exposure noise performance without NR. More specific, does it produce a lot of hot pixel for exposure longer than 15s?
    On two occasion, I forgot to take dark frames before/after shooting couple hundred of photo for time lapse and star trial with my GX7. The result were pretty bad due to the hot pixel along the edge of the frame, and pretty much can't do anything about it.
    Since Adorama and BHphoto is actually running quiet a sale right now on the GX8 with the new weather seal zoom, I am a bit tempted. After selling the lens and my gx7 I could net an upgrade with just 200~300 dollar. Want to make sure if the upgrade is worth it here. I don't really need the other 4K stuff on GX8, but if the noise performance alone yields a significant difference I may pull the trigger.
     
  2. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    While I don't have any first-hand experience, I do know that LEN performance can vary widely depending on the camera. My GH4 is very good in this regard, while my E-M1's are absolute rubbish.

    But in this review, there is a blurb talking about LEN of the GX8, compared to the GX7 specifically, and this is what the author had to say:
    "If you love doing long exposure photography, you’ll like it that the maximum (bulb) exposure time has increased from GX7’s 4 minute to 30 minute. Not only that, the new sensor seems to be much better when handling long exposure noise, and the long exposure are much cleaner than it’s predecessor. I did a 1 minute long exposure at ISO200 and the result looks great even without any long exposure noise reduction applied, something the GX7 would struggle unless you turn on the long exposure noise reduction"
    Sadly, no sample images were given to showcase the differences, but this does align with what I've reach in other reviews as well with regards to the GX8's LEN performance
     
  3. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Yea that's the review I came across too, some people also mention that gx8 used a similar tech in long exposure to the gh line which is different with gx7. Does ur gh4 support long exposure beyond 4min? And how's the result looking for say a iso 1600 / 15s exposure? Thx~ :)
     
  4. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    Yeah, my GH4 can do over 4 minute exposures. The longest I've done was a 9 minute exposure. However I always use LENR when shooting long exposures. Also, virtually all of my LE's are done at ISO 200, so unfortunately I can't answer your question about 15s exposures @ ISO 1600.

    I assume since you mention those conditions, that you're looking to do astro work, no? If so, m43 is very challenging to use. I've seen users do it before, but they've said that it takes some work in post to get the exposure level to where it needs to be, without introducing a ton of noise in the image. M43 struggles with shadow noise in LE's, and I've seen it with my GH4.

    Ultimately, if you plan on doing a lot of LE work, m43 may not be the best system for that. I have heard very good things about Fuji's LE performance though with regards to noise. I presume this must be due to the x-trans sensor compared to a traditional Bayer sensor. In theory, you could pick up something like an X-E1 and some manual focus Samyang lenses, which will likely give you a better result in terms of noise performance when dealing with LE's, especially at elevated ISO's.
     
  5. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Fwiw, xtrans is just a different color filter (and matching software) over a Sony sensor.
    Noise differences must be from some other aspect of the sensor or any NR algorithms.
    Iirc, I've seen lots of allegations that Fuji applies NR to all RAW files.
     
  6. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    ya I am looking for a more viable system for some wide field Astro work. Thought about picking up a used 6D and some 3rd party lens, but knowing myself I will probably dump more money and research time than I should have into it if I go for a new system :doh: gonna take my Ricoh gr for a try next time if result is good I may just get a wide angle adapter.
     
  7. wjiang

    wjiang Mu-43 Hall of Famer

    General low signal long exposure noise is a somewhat different issue to hot pixels. You will need to use dark frame subtraction (whether in camera or otherwise) to deal with hot pixels in any camera system. General low signal long exposure noise cannot be cured completely using dark frame subtraction, however, as it has significant random components - only a higher signal-to-noise ratio will improve this. This can be achieved through a better signal processing pipeline (camera specific), bigger light wells (i.e. bigger sensor with reduced pixel density), reduced ISO through faster apertures or longer exposures (for astrophotography it probably needs to be guided), or aligning and stacking multiple frames.
     
  8. tody

    tody Mu-43 Regular

    26
    Nov 6, 2011
    I tried on my GX85 in Cabo and there are some hot pixels at iso 800. This shot was shot with the kit lens at 13mm, iso 800, f8 and 13s.
    P1030581-1.
     
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  9. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Sold my gx7 and grabbed the gx8 from adorama. Tho it is a bit sad to part with the camera after it been with me to Japan twice and some extreme place like Death Valley, but I guess i lucked out only lost 80 bucks after two years of use.
    I will post what I find out after I got the gx8 and some test shots.
     
  10. cnyap

    cnyap Mu-43 Regular

    60
    Jan 30, 2015
    Brighter/faster glass is the cheapest way to improve night shots.
     
  11. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Depends, really. The only way to improve on a Samyang 7.5/3.5 is a Oly 8mm/1.8, and that's an $800 lens...

    M4/3 doesn't have a fast cheap ultrawide like the Samyang 12mm/f2 for APS-C, or the 14mm/f2.8 for full frame. A <$400 cheap 9mm/f2 would be really tempting, even if it was manual focus.
     
  12. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Already using a f1.7, to go faster than that in uwa for m43, it is only the voiglander 10.5 and the new panaleica 12 now. Both cost a premium.

    On the side node, gx8 long exposure does seem much better than gx7 in term of minimizing hot pixels. I haven't done a through test yet, but a couple 20sec shots in my back yard without NR seems cleaner than the gx7 with NR. I will do some more test once the moon phase is right.
     
  13. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Given that I see significant purple amp noise creeping into my GX7 shots by the 30s mark, the fact the GX8 even allows 4 minutes seems like it must be dramatically better. It's a Sony sensor, and the Sony sensors have always been better in this respect (perhaps excepting the GH4 with its optimized heat dissipation design tailored for video?), so I would believe the GX8 to be way better.

    I believe the Optyczne.pl review of the GX8 bears this out, as well.
     
  14. cnyap

    cnyap Mu-43 Regular

    60
    Jan 30, 2015
    The image above was shot at f8...
     
  15. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    I think most of us worrying about long-exposure amp noise tend to be shooting at high ISO and wide apertures in order to capture stars. I find it's kind of a non-issue, even with my GX7, below ISO 1600, but rears its head pretty badly at ISO 6400.
     
  16. O2BanRRT

    O2BanRRT Mu-43 Regular

    164
    Jun 25, 2012
    Waterloo, Ontario (Canada)
    Jean
    Here's what I found that works for low light star photos ... just a newbie here!
    Samyang 16mm f/2 with a Metabones Speedbooster (effective 11.5mm f/1.4) - it can only be considered cheap if you already have a speedbooster!
    Here's a recent sample on a GX7 wide open 15 Sec.
    MissinaibiRiver_160729_%281860of2319%29-HDR-X3.
    Cheers!
    Jean