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E1 red and blue pixels. Why?

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  • E1 red and blue pixels. Why?

    Camera E1; lens 14-54
    Software Photoshop CS and Lightroom3
    ISO100, 14mm , f6, 6.0 sec
    Used a tri-pod
    I had an opportunity to photograph the inside of an old barn. With low available light I shot 145 raw images in about 2 hours. After sorting I processed the first images I shot and noticed nothing unusual. When I processed one of the last images in Lightroom 3 I noticed a lot of scattered red and blue pixels. In Photoshop CS the pixels are there but colorless. Going back to the first images there are a fewer scattered red and blue pixels.
    Why so may scattered colored pixels? I think this is more than colored noise.
    The photo E1 red and blue pixels is a 200x close up of a wagon wheel.
    Thank You Casey
    Attached Files

  • #2
    Re: E1 red and blue pixels. Why?

    could be thermal noise if camera has been on for some time

    Comment


    • #3
      Re: E1 red and blue pixels. Why?

      Mine does the same thing on exposures of 1 sec. or more.

      Sometimes I forget to turn the noise reduction on, and the red and blue pixels show up.

      Comment


      • #4
        Re: E1 red and blue pixels. Why?

        There is a noise that shows itself at long exposures, and there is dark frame substraction method to counter that - Noise Reduction function (in menu).

        First, I would run Pixel Mapping, just to be sure, then take two pictures of the same scene - one with Noise Reduction Off and second with NR On.
        The one with NR On should be without visible color pixels, if not, there is something wrong with your camera.
        Regards, Pavel.

        E-1(x2) | ZD 14-45 | ZD 14-54 | ZD 40-150 Mk.1 | ZD 70-300 | FL-50 | Velbon Sherpa 750R
        M42(Pancolar 50/1.8, Pentacon 200/4)+ M42->4/3 reduction

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        • #5
          Re: E1 red and blue pixels. Why?

          Ditto to what Pavel said.
          Regards Paul.
          One day I hope to be the person my dogs think I am.

          http://www.pbase.com/paulsilkphotography
          https://www.flickr.com/photos/paul_silk_photography/

          Comment


          • #6
            Re: E1 red and blue pixels. Why?

            Thank you all for your input. I had not herd the terms thermal noise and dark frame subtraction. First I will turn the Noise Reduction function on and experiment with it. If that does not work. I will try dark frame subtraction. I found a few sites and free programs that deal with this method.
            I'm pretty sure my camera is ok. I went out the next morning and shot some low light first light photos. I checked those photos and did not see any thermal noise.
            If the Noise Reduction function works, I will be turning it on when exposing for 1 sec. or more. I always thought of Noise Reduction function was more for dark midnight skies.

            Thank you again I learned a lot.
            Casey

            Comment


            • #7
              Re: E1 red and blue pixels. Why?

              Anyone hear of Faceman's Hot Pixel Remover? I was going to try to use it on the photos with all the thermal noise. But I can not figure out where to place it in my plugins in Photoshop CS.
              Thank You
              Casey

              Comment


              • #8
                Re: E1 red and blue pixels. Why?

                Originally posted by Casey50 View Post
                Thank you all for your input. I had not herd the terms thermal noise and dark frame subtraction. First I will turn the Noise Reduction function on and experiment with it. If that does not work. I will try dark frame subtraction. I found a few sites and free programs that deal with this method.
                I'm pretty sure my camera is ok. I went out the next morning and shot some low light first light photos. I checked those photos and did not see any thermal noise.
                If the Noise Reduction function works, I will be turning it on when exposing for 1 sec. or more. I always thought of Noise Reduction function was more for dark midnight skies.

                Thank you again I learned a lot.
                Casey
                In practice you can leave Noise Reduction on as it only cuts in for long exposures when it is likely to be needed. Unlike Noise Filter it also works on both raw and JPEG files.
                View my ebook, The Light Fantastic, at: http://store.blurb.co.uk/ebooks/3026...ight-fantastic

                John

                Comment


                • #9
                  Re: E1 red and blue pixels. Why?

                  Good to know. I've decided to re-shoot the barn. I'm' going to let the camera do the work.
                  Thank You
                  Casey

                  Comment


                  • #10
                    Re: E1 red and blue pixels. Why?

                    the bad thing with NR is that it reduces the buffer to 1 image only - so in normal conditions it could be distracting.
                    luckily you didn't got upper left corner burned out - i was also guided to same way. found out later that it's also talked about in dpreview E1 test
                    E-1; E-520; E-M10; ZD 14-42; ZD 35+CIR-PL; ZD 40-150; FL-36R; Metz 52-AF1

                    Comment


                    • #11
                      Re: E1 red and blue pixels. Why?

                      Originally posted by throt View Post
                      the bad thing with NR is that it reduces the buffer to 1 image only - so in normal conditions it could be distracting.
                      luckily you didn't got upper left corner burned out - i was also guided to same way. found out later that it's also talked about in dpreview E1 test
                      Not sure if I'm just repeating what you've said, but don't use sequenced shutter selection as that will disable the NR (which is dark frame subtraction) & you will still see them hot pixels peakin' with red & blue through your image.
                      Ross
                      I fiddle with violins (when I'm not fiddling with a camera).
                      Cameras: OM-D E-M1 & Mk II, Olympus Stylus 1, OM-D E-M5.
                      Lenses: M.ZD12-40mm f2.8 PRO Lens, M.ZD40-150mm f2.8 PRO Lens with MC-14, M.ZD12-50, M.ZD60 Macro, M.ZD75-300 Mk II, MMF-3, ZD14-54 II, Sigma 150mm F2.8 APO Macro DG HSM.
                      Flashes: FL36R X2, FL50R, FL50.
                      Software: Capture One Pro 10 (& Olympus Viewer 3).

                      Comment


                      • #12
                        Re: E1 red and blue pixels. Why?

                        Originally posted by Ross View Post
                        Not sure if I'm just repeating what you've said, but don't use sequenced shutter selection as that will disable the NR (which is dark frame subtraction) & you will still see them hot pixels peakin' with red & blue through your image.
                        You cannot use shooting in sequences when NR is active, camera will not allow you to select it.
                        Regards, Pavel.

                        E-1(x2) | ZD 14-45 | ZD 14-54 | ZD 40-150 Mk.1 | ZD 70-300 | FL-50 | Velbon Sherpa 750R
                        M42(Pancolar 50/1.8, Pentacon 200/4)+ M42->4/3 reduction

                        Comment


                        • #13
                          Re: E1 red and blue pixels. Why?

                          Originally posted by T-Lama View Post
                          You cannot use shooting in sequences when NR is active, camera will not allow you to select it.
                          That's true & after the setting has been turned ON (which would normally be left on auto NR), in the heat of the moment, it is too easy when shooting in sequence shutter for one use, to change it back to single shutter when NR is important. Well, that's what happens to me if I don't double check.
                          Ross
                          I fiddle with violins (when I'm not fiddling with a camera).
                          Cameras: OM-D E-M1 & Mk II, Olympus Stylus 1, OM-D E-M5.
                          Lenses: M.ZD12-40mm f2.8 PRO Lens, M.ZD40-150mm f2.8 PRO Lens with MC-14, M.ZD12-50, M.ZD60 Macro, M.ZD75-300 Mk II, MMF-3, ZD14-54 II, Sigma 150mm F2.8 APO Macro DG HSM.
                          Flashes: FL36R X2, FL50R, FL50.
                          Software: Capture One Pro 10 (& Olympus Viewer 3).

                          Comment

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