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Re: About in-camera noise reduction..

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  • hewholooks
    Don t count on it! ;- Hunter ... conclusion.
    Message 1 of 27 , Feb 1, 2008
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      Don't count on it!

      ;->


      Hunter

      --- In DeepSkyStacker@yahoogroups.com, "Dennys" <gowron35@...> wrote:
      >
      > Never would have guessed that my question would have triggered such a
      > debate.
      > By the time I get my new camera, we surely will have reached a
      conclusion.
      >
      > LOL,
      > Clear skies to all!
      >
    • Ciobotas
      Lol, you may be right there Hunter. Actually, it s probably a good thing everyone tries all the options and settle on the one that works best for them. All
      Message 2 of 27 , Feb 1, 2008
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        Lol, you may be right there Hunter. Actually, it's probably a good
        thing everyone tries all the options and settle on the one that works
        best for them. All kinds of factors influence this kind of
        photography, and no two setups are alike.

        Alec, you're very welcome, always try to help others.

        Simon, thanks for doing the test! Yes, it does indeed look like the
        final pic with darks has a bit more chroma noise. I also agree with
        Luc, it would be interesting to see a progression of darks and the
        behavior with each set. As far as vignetting and SNR, yep, it would
        be mostly towards the edges, you're right.

        And Dennys, this is actually fun stuff for me. :-) I'm always the
        maverick (ok, some call me just plain odd), and I like to think
        outside the box and try things that seem stupid... well, some _are_
        stupid, but that doesn't stop me. I think this is a great discussion,
        and I hope everyone learns something from it, including me.

        Clear skies,

        Daniel
      • Simon Hicks
        Hi Daniel, No problem, it was easy to do the tests...cos I had the data at hand...and I was really intrigued by what the result would be....and like you, I
        Message 3 of 27 , Feb 1, 2008
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          Hi Daniel,
          No problem, it was easy to do the tests...cos I had the
          data at hand...and I was really intrigued by what the result would
          be....and like you, I like to try the things outside the box to get a
          better understanding...which is why I always ask so many questions as
          well.

          I thought it was really clear when I looked at the results....get rid
          of the darks and the noise looks less. And then Luc spoilt my moment
          of euphoria by resorting to facts and logic (d'oh!).

          Luc. I see your point. I had assumed that the apparent larger
          amplitude of variation in the dark-subtracted image was a reflection
          of noise in the image. I sort of picked a dark bit of background in
          the image that I sort of assumed was 'flat'. But I guess your point
          is that it might actually be a reflection of real structure (signal)
          in the image....and it is emphasised when the dark is subtracted.
          After all, I had really aggressively stretched the image to actually
          see the noise, so I might well be seeing something real but right on
          the edge.

          So when I realised I didn't have the original flats to finish the
          test my heart sank...Oh so very close to the answer and yet still a
          million light years away! I'm loathed to promise when I'll take a
          load of new darks and lights and redo the test properly because a)
          its been a month since we had clear skies here in Glasgow and b) I'm
          just so depressed at not saving the first set! But I will try to redo
          the tests sometime and report back.

          Dennys...by the time we work this out, cameras won't have noise and
          we can all rest easy. :-)

          Cheers
          Simon
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