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Long Exposure Noise Reduction setting

Discussion in 'Panasonic Cameras' started by Trigger, Jun 12, 2013.

  1. Trigger

    Trigger Mu-43 Regular

    53
    Jun 11, 2013
    Panny G3.

    Is it deleterious in any way to leave the LONG SHTR NR setting in the "ON" setting when taking regular shots? The default is "OFF", so I'm wondering if it should be off when not in use.
     
  2. RobWatson

    RobWatson Mu-43 Hall of Famer

    Higher noise is the result - that and the extra time are the only deleterious consequences I can think of.
     
  3. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    And I use it all the time and for all the theoretically higher noise that is present -- in terms of impact on my subject matter it is negligible at best.

    Furthermore, I don't remember how many seconds you have to shoot before it kicks in, but it only does on very long shutter speeds of about a second or longer. Check the manual as I don't remember the exact amount. For most normal shooting it does not kick in at all and therefore has no impact whatsoever.

    It's only purpose is to get rid of "hot pixel" type noise. All my cams have that selected ON all the time.
     
  4. Trigger

    Trigger Mu-43 Regular

    53
    Jun 11, 2013
    Hmm, I don't think it "kicks in" at all; it's either on or off depending on whether it's set to be on or off. (?)

    Yes, I use it when doing long exposures like 10-20 seconds using an ND 8 filter. I think it helps eliminate noise for those situations. But I'm wondering what effect it might have (ON) when doing normal daylight shooting.
     
  5. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
  6. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    Nope. It only engages on long exposures -- hence what it is called, lol: LONG shutter noise reduction. It is definitely not engaged at shutter speeds faster than something I can't recall -- but I do know the principle.
     
  7. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    Trigger:

    From the Panasonic G5 manual, G3 is similar if not identical:

    The camera automatically removes noise that appears when the shutter speed becomes
    slower
    to take pictures of night scenery etc. so you can take beautiful pictures.


    In other words, it automatically works when required, "kicking in" as needed.

    EDIT: Just checked my GX1 and it kicks in at 4 seconds. At that point, after the exposure counts down, the second screen pops up counting down the dark frame exposure. Faster than 4 seconds this doesn't happen.
     
  8. Trigger

    Trigger Mu-43 Regular

    53
    Jun 11, 2013
    Hmm, if it kicks in only when needed, then why would it have an On or Off option? Who would say to themselves: I want some noise in my photo, I better turn that LE NR off!

    :smile:
     
  9. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    If you read that other thread that was linked, you'll see that not everybody is sanguine about the results. I and some others are, a few aren't. Some people prefer to manually edit hot pixels but if I was photographing stars? I don't think I'd want to find those needles in the haystack, lol.

    If you have a Panasonic camera you can do the same test I just did, then turn it off and you'll see that it doesn't do anything at 4 seconds and over. It's a choice just like so many other options in the camera according to ones artistic and technical requirements. It's a good thing really -- but for me it's a no-brainer: it stays ON, lol.
     
  10. kiawui

    kiawui New to Mu-43

    2
    Jun 18, 2013
    Singapore
    Dennis
    The reason why there is an on and off is as follows.

    If On, this is normally for people who does not do any pp and will let the camera do the noise reduction and therefore results in the screen going black and counting down to whatever seconds that was used to take the shot.

    If Off, this would be for people who does pp and most probably do not want to wait for the camera to do the noise reduction and having to wait for the black screen to countdown before taking another photo.
     
  11. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    I do lots of PP and I use the setting so there are exceptions, lol.
     
  12. monk3y

    monk3y Mu-43 Hall of Famer

    May 14, 2013
    in The Cloud...
    Steven
    Even though apply some pp to my photos, I still leave it on... for some reason I find the m43 photos a little bit noisier than FF at base ISO on long exposures. Turning this on at least lessens that gap "For Me".

    Sent from my GT-N7100 using Mu-43 mobile app
     
  13. swampduck

    swampduck Mu-43 Veteran

    334
    Mar 29, 2013
    Taneytown , MD
    Dan
    I had to look the word up...but I just broadened my vocabulary.

    deleterious : harmful often in a subtle or unexpected way
     
  14. kiawui

    kiawui New to Mu-43

    2
    Jun 18, 2013
    Singapore
    Dennis
    Well, I guess I should put it this way. If you do not wish to wait long before taking another picture, then turn it off at the expense of in camera noise reduction. Sometimes a shutter of 60 secs can be quite long for some. :)
     
  15. Trigger

    Trigger Mu-43 Regular

    53
    Jun 11, 2013
    Thanks all. How do you think the in camera NR compares to a NR treatment in Photoshop or NIK Define? The wait after the shot is taken is the same amount of time than the exposure (20 second exposure = 20 second process time) and this usually feels like an eternity out in the field.
     
  16. entropicremnants

    entropicremnants Mu-43 All-Pro

    Jul 16, 2012
    John Griggs
    You can't properly do dark frame subtraction in PP without taking a frame right after the frame you just took -- in other words making two exposures so there is no advantage.

    I think once again many don't understand what this NR is for: it is not the NR you find in Lightroom, or Photoshop or NIK. That is for the normal distributed "random" noise that affects the entire image.

    Dark frame subtraction takes care of a systematic false signal in individual pixels that tends to accumulate with long exposures particularly with dark subjects or backgrounds. Normally this is referred to as "hot pixels".

    It can be spotted out manually in post -- but for people who do astrophotography for instance think of the work trying to distinguish a hot pixel from a star! That's why it is so common there.

    The direct answer to your question is: you can't compare them because post processing noise reduction doesn't recognize hot pixels as noise.

    Some editors do allow you to do dark frame subtraction in post. But hot pixel noise comes and goes. There can be pixels that always do it, and others will only sometimes do it. Because of this, you can't keep a master dark frame and address all the noisy pixels because they might be there one time, and not the next.

    And that is the LAST post I'm doing on this subject because it's now been covered again and again in multiple topics and one of the things I get tired of no forums is repeating myself, lol. NO KNOCK against the fellow (Trigger) who asked the question -- this is strictly my personal pet peeve.

    Hope that helps you understand.
     
  17. Trigger

    Trigger Mu-43 Regular

    53
    Jun 11, 2013
    Thanks. So should one only use the in camera NR if and when one discovers a hot pixel, or can the hot pixels come & go based on their mood or the shot taken?
     
  18. RobWatson

    RobWatson Mu-43 Hall of Famer

    Some reading on the dark current/hot pixel stuff

    Understanding CCDs – Dark Current versus Noise | Capturing Light

    http://www.imagesensors.org/Past Workshops/2005 Workshop/2005 Papers/37 Pain et al.pdf


    Particularly relevant to our types of cameras is this one

    Dark Current in Consumer Cameras: Not What you Expect (photonics.com | Sep 2010 | Web Exclusives)


    Just be aware that not every article gets everything correct and sometimes misleading comments are made. The general idea is pretty clearly stated but specific methods of correction are possible but each has its own strength/weakness.

    Technical diversion:
    One method I never hear talked about is using the fact that the Bayer mask results in a very specific ratio amongst the de-Bayered pixels that can be used to infer the de-Bayer parameters (for a given WB, etc). Using this info pixels can be identified as hot pixels and corrected in post to eliminate the pixel-pixel "spikes" inherent in dark current distributions. A star may well be a single pixel but the de-Bayer ratios will not match that of a hot pixel so a smart filter working with these ratios can pass over the star but work aggressively on a hot pixel. Generally speaking stars do not show as single pixels but hot pixels always do (or pairs or pixels). Close inspection of star field images reveals many subtle details that can be used to distinguish stars from hot pixels even in very undersampled images.