Long exposure, processing time on Lumix

Discussion in 'Panasonic Lumix' started by Wills, Sep 13, 2005.

  1. Wills

    Wills Guest

    I have a Panasonic Lumix DMC-FZ20 camera and have been taking some long
    exposure shots of 8 second (lightning).

    The camera take another 8 seconds to process the pictures (at which time the
    lightning strikes!)

    Can anyone explain why this is, and do all digital cameras behave the same?
    If not then which are the fatest.

    Ta
     
    Wills, Sep 13, 2005
    #1
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  2. Wills

    Aad Guest

    It's prob. to do with (in camera) long exposure noise reduction.
    Turn it off and look at the differences.
    Aad
     
    Aad, Sep 13, 2005
    #2
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  3. Wills

    John Bean Guest

    It's a technique called "dark frame subtraction", and most
    cameras do this for long exposures. The noise generated by
    the sensor builds up as the time increases in a way that's
    consistent for the particular sensor in the particular
    situation in which it's being used. After the "real"
    exposure finishes the camera makes another identical
    exposure but with the shutter closed - the "dark frame" -
    which has the same noise pattern as the real exposure. This
    is then subtracted from the original, cancelling most of the
    noise without hurting the image detail.
     
    John Bean, Sep 13, 2005
    #3
  4. Wills

    News Will Guest

    Thanks. That's something on the lines I was thinking.
    Unfortunaly it's not possible to switch off noise reduction, reducing it
    does nothing.

    I have a friend who has a Nikon D100, which gives control back 'immediately
    it finishes saving, but there's no way I can afford a D100 and the selection
    of lenses of 35 -400mm equiv!

    However I do have a wide selection of Pentax lens, so if some kind reader
    has a Pentax *ist DS, perhaps they could let know if there is a considerable
    recoverey time on on of these cameras.

    Thanks
     
    News Will, Sep 15, 2005
    #4
  5. Wills

    John Bean Guest

    I also have a DS :)

    Dark frame subtraction is done by default for exposures
    longer than a second but it can be turned off if you so
    desire - first item in the Custom Menu: "Noise rediction"
    on/off.
     
    John Bean, Sep 15, 2005
    #5
  6. Wills

    News Will Guest

    I DON'T have a DS, but am considering getting one.

    Perhaps you can tell me, how long after a 8+second exposure, before you can
    take another picture.
    Unfortunately this is not available on the Lumix

    Ta
     
    News Will, Sep 15, 2005
    #6
  7. Wills

    John Bean Guest

    I used "also" because I have a DS as well as a Panasonic,
    not because I thought you had a DS.
    I thought I already had. I already explained that the delay
    is caused by the dark frame subtraction (noise reduction)
    process, so ...

    .... if you turn it off there's no delay. Hope that's
    clearer.
    Yes, but you asked about the DS...
     
    John Bean, Sep 15, 2005
    #7
  8. Wills

    News Will Guest

    [Posted and mailed]

    It's been a long hot sticky day!
    Thanks very much, I hope to have a DS soon :)

    Willie
     
    News Will, Sep 15, 2005
    #8
  9. Wills

    News Will Guest

    It's been a long hot sticky day!
    Thanks very much, I hope to have a DS soon :)

    Willie
     
    News Will, Sep 15, 2005
    #9
  10. Wills

    John Bean Guest

    I blame age when I do it :)
    It's a nice camera, you'll like it - especially if you
    already have some nice Pentax lenses.
     
    John Bean, Sep 15, 2005
    #10
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