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Lots of Noise On Long Exposures

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  • Lots of Noise On Long Exposures

    Hi All,

    I thought I had seen a post about this, but have been unable to find it.

    Whilst in the Lake District last week I took a number of long exposures with the Lee big stopper.

    It seems that some of these are showing very high levels of noise. In the guise lots of coloured dots.

    I have tried to import into LR5.2 and 5.3 as dng, and raw, but that makes no difference. I have imported into Olympus Viewer and that makes little difference.

    I have also tried moving between software and adding noise correction but there is little improvement between them all.

    Have we managed to find an answer that I have missed to this serious problem?

    Best regards

    Chris

  • #2
    Re: Lots of Noise On Long Exposures

    First question, Chris, is do you have Noise Reduction switched on? This should not be confused with Noise Filter, they are two entirely different functions.
    John

    "A hundredth of a second here, a hundredth of a second there even if you put them end to end, they still only add up to one, two, perhaps three seconds, snatched from eternity." ~ Robert Doisneau

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    • #3
      Re: Lots of Noise On Long Exposures

      Hi John,

      I have Noise reduction off as I did with the EM5. Noise filter is set to Standard.

      Best regards

      Chris

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      • #4
        Re: Lots of Noise On Long Exposures

        Well, surely the question is how many are lots. Assuming lots is a reasonable number, under 50 or so. Then what you've probably got is hot pixels. Might be worth running pixel mapping which I'd guess is under one of the spanner menus.

        Noise Reduction is dark frame subtraction, which you should have on for long exposures as it takes away a lot of the pixel noise.

        Personally I suspect that live view sensors are more prone to hot pixels as they are on constantly.

        Unfortunately I don't have an E-M1.

        Mayhaps a crop of a shot taken, with exif, could be useful for the group to help diagnose any problems.

        Nick
        Nick Temple-Fry

        Medicine as a science ranks somewhere between archaeology and economics.

        www.theChurchPhotographer.co.uk 90 Churches -- Fairford St Mary's, exceptionally splendid
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        • #5
          Re: Lots of Noise On Long Exposures

          You need Noise Reduction on - will make a big difference I expect.

          Ian
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          • #6
            Re: Lots of Noise On Long Exposures

            Originally posted by Ian View Post
            You need Noise Reduction on - will make a big difference I expect.

            Ian
            It's not even a question of switching it on - the default setting is AUTO and it's triggered by both the exposure period or sensor temperature ie you would expect it to be triggered for a shorter Livetime exposure or Livecontrol than when shooting with the eye away from the viewfinder, as well as when taking a large number of longer exposures.

            There certainly appears to be some differences in the implementation of the E-M5 settings in this area and the E-M1, but that's not as relevant to the E-M1 as it is to those who have expectations from it based on the E-M5 in this area (primarily astro multi exposure as I understand it).
            E, Pen and OM-D bodies
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            • #7
              Re: Lots of Noise On Long Exposures

              The issue is, that it was not a problem on the EM5 but is on the EM1.

              There is no reason for using noise reduction in camera, but it would seem from reading elsewhere that it is needed in the EM1. Not a huge problem for landscape photography, but definitely an inconvenience. I take photos that may mean a 10 minute exposure, then you would have to wait for another 10 minutes for the noise reduction. I have never owned a camera that needs this and the EM1 is a 'pro' camera!

              Not good really.

              Best regards

              Chris

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              • #8
                Re: Lots of Noise On Long Exposures

                I take it "auto iso" isn't on?

                Steve
                http://www.flickr.com/photos/smj41/

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                • #9
                  Re: Lots of Noise On Long Exposures

                  Originally posted by SteveJ View Post
                  I take it "auto iso" isn't on?

                  Steve
                  Hi Steve,

                  No, I don't use auto iso for landscape with a tripod.

                  Everything is 'exactly' the same as when using the EM5. The only difference is the noise.

                  But as mentioned I have discovered that this is a problem with the EM1 and the only answer is turn the noise reduction on, in camera. This is a poor excuse from Olympus. I have not discovered what the difference is, with the two cameras that make this happen, but believe Olympus need to check it out ASAP.

                  Suddenly our EM1's are not the camera we wanted them to be. Yes, turning the noise reduction on makes it work, but it is a workaround.

                  Best regards

                  Chris

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                  • #10
                    Re: Lots of Noise On Long Exposures

                    I was hoping to do plenty of astrophotography with the M1. The dark frame subtraction will sort the hot pixels out but will be awkward when shooting deep space images if for example i need 8x20min (or more) exposures this will have to be done over several evenings (and probably with a different camera anyway). I still have the EM5.

                    You're right Chris, the EM1 isn't the camera we were hoping for. It's an excellent camera for mainstream purposes, but definitely not PRO. Olympus need to come out the shadows and show some backbone by addressing users concerns.
                    __________________
                    Pete


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                    • #11
                      Re: Lots of Noise On Long Exposures

                      I didn't think that dark frame subtraction for long exposures was exclusive to Olympus cameras. I suspect that to do noiseless long exposures without DFS something like a full frame 12mp camera such as a Nikon D3s might be required.
                      John

                      "A hundredth of a second here, a hundredth of a second there even if you put them end to end, they still only add up to one, two, perhaps three seconds, snatched from eternity." ~ Robert Doisneau

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                      • #12
                        Re: Lots of Noise On Long Exposures

                        Originally posted by Zuiko View Post
                        I didn't think that dark frame subtraction for long exposures was exclusive to Olympus cameras. I suspect that to do noiseless long exposures without DFS something like a full frame 12mp camera such as a Nikon D3s might be required.
                        Indeed, but the EM5 way outperforms the EM1 with long exposures without NR/DFS. Judging by the discussions out there and the examples i've seen the EM5 performs brilliantly with long exposures, leading to suggestions that it's cooking the RAWs in-camera. I don't know what's going on with the EM5 but the EM1 struggles with exposures over 60 secs. Admittedly not an issue for most.
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                        Pete


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                        • #13
                          Re: Lots of Noise On Long Exposures

                          This is interesting read. Also a few links to other discussions from that page. This isn't a deal breaker for me, but it is one intended use i may have to rule out for this camera. Soon i'm moving house to a 'dark sky area'.

                          http://www.seldomscenephotography.co...ong-exposures/
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                          Pete


                          https://www.flickr.com/photos/122278067@N06/

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                          • #14
                            Re: Lots of Noise On Long Exposures

                            Originally posted by bredman View Post
                            Indeed, but the EM5 way outperforms the EM1 with long exposures without NR/DFS. Judging by the discussions out there and the examples i've seen the EM5 performs brilliantly with long exposures, leading to suggestions that it's cooking the RAWs in-camera. I don't know what's going on with the EM5 but the EM1 struggles with exposures over 60 secs. Admittedly not an issue for most.
                            I think it's more likely that the E-M1 is "cooking raws" (most amusing concept).

                            In order to provide the PD focusing that many wanted a number of green pixels in the centre of the sensor have had to be sacrificed. This missing data has to be replaced by interpolation from the surrounding green pixels.

                            All electronic devices produce electrical "noise" the generation of which increases with temperature. When a sensor is left "on" for a long exposure it generates heat which in turn produces more noise. The new sensor also has better high ISO noise characteristics (which "every one" wanted) so is inherently a "different" sensor to that in the E-M5. It is invariably the case that in solving one problem compromises have to be made which result in the loss or change of capability in another area.

                            With all respect I can't imagine that the use of their cameras for amateur astro photography is a factor that weighs heavily with Olympus' designers when considering the market they are hoping to maximise sales in. Neither can I see that a perceived shortcoming in one very specific application makes a camera "not PRO grade", whatever that means. I seem to remember that "back in film days" there were certain models of camera that were considered "better" for astro photography than others and I guess nothing has changed.

                            Just my thoughts.
                            Peter

                            she looked at me and said "It's official. I hate your camera. It's just so amazing and perfect I want one!"

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                            • #15
                              Re: Lots of Noise On Long Exposures

                              Hi Chris I think I understand your problem. I found out about this when taking pictures of fireworks albeit circa 8sec exposures.

                              http://e-group.uk.net/forum/showthre...811#post261811

                              http://e-group.uk.net/forum/showthre...206#post262206

                              Although at the time I thought this was only related to livetime I have seen it on other exposure modes.

                              I do not think this is a NR issue I had NR on when I took these. What does seem to make a difference for in camera jpg is to set the NF to high. The noise I experienced were black dots which only appeared when processed through in camera jpg and OV3.

                              When I took raw only pictures converted them to dng and then viewed them in LR4.4 (at the time I did not have LR5.2) this noise was not there.

                              I have an open issue logged with Oly support about this.

                              Only yesterday I found the flickr thread "Long Exposure issue with OM-D E-M1?" referred to in bredmans post and I am confused because it appears that they tried raw and processed through LR5.2 and found no difference. Others are reporting it going away.

                              My own take on all of this fwiw is that there is a in camera jpg processing problem. But lets be absolutely sure that you do not get it when raw processing.

                              When you say you processed the file to dng was that from a raw only file or did you take raw+jpg?

                              I suspect that not that many on this forum are noticing this because they shoot raw and do not use OV3 for processing.

                              Just trying to help as this is a real serious issue for as I like long exposures eg light trials.
                              John
                              John

                              OM-D E-M1, 12-40 f2.8 Pro, Tamron 14-150mm f5.8, E5, E3, Zuiko 50-200mm SWD, Zuiko 12-60mm SWD, Zuiko ED 70-300mm f5.6, 50mmf2, Zuiko ED 9-18mm f5.6, Sigma 50-500mm f6.3, EC14, EC20, RM-1, VA-1

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