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blue noise in long exposures (e-pl1)

Discussion in 'Olympus Cameras' started by adamk9, May 7, 2011.

  1. adamk9

    adamk9 New to Mu-43

    May 7, 2011
    Hey, I was wondering if anyone knows why there is overwhelming blue noise in a 2 minute exposure, iso 100, and f/22? The camera is an Olympus PEN E-PL1.

    I'm also wondering why the amount of time the camera takes to save the image seems to be the same as the exposure time, so if I expose for 1 minute, then after 1 minute I hear a click then it shows an orange icon in the corner, and after another minute there is another click and the image shows up.
  2. shoturtle


    Oct 15, 2010
    M4/3 sensor are not the best for long exposure. 2 minute really stress the sensors, causing allot of noise.

    For long exposure of more then 60 sec, I use my aps-c dslr for that application. Due to the noise form the smaller sensor on long exposures.

    the first click is the shutter closing, the second it when the camera process the image. It does take a while with a long exposure. Not sure why.
  3. F1L1P

    F1L1P Mu-43 Veteran

    Jan 2, 2010
    I think this is not specific to m43 cameras, but to most digital cameras. Blue channel is more prone to noise. I'm not sure is that dependent on sensor technology or color wavelenghts.

    Probably it is not saving the image, but doing dark frame subtraction.
    Dark frame subtraction - Wikipedia, the free encyclopedia
    first click is probably shutter closing to take an image of nothing - black frame, and after it is completed, shutter opens to enable live view.
    This can be turned off in Panasonic G1, not sure for Olympus, sorry. There should be such option in menu somewhere.
    You can always remove noise on your PC. It will probably even be better at it.
  4. shoturtle


    Oct 15, 2010
    that is true that all digital camera that blue channel can get noisy with long exposures. But with the larger sensors the problem is allot less.
  5. Djarum

    Djarum Super Moderator Subscribing Member

    Dec 15, 2009
    Huntsville, AL, USA
    A 2 minute exposure could be getting the sensor hot, too. Larger sensors typically can dissipate heat quicker and the electronics aren't as dense and close together. Dark frame subtraction could help. Actively cooling the sensor might help too.
  6. DanGuy48

    DanGuy48 Mu-43 Regular

    blue noise

    Under those conditions, blue noise is not surprising. Silicon based sensors are notoriously insenstive to blue light. Therefore the blue channel usually has some gain applied to give a proper relative intensity to the other channels; so the blue channel is the first to show a problem like this.
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