Re: About in-camera noise reduction..
- View SourceDon't count on it!
--- In DeepSkyStacker@yahoogroups.com, "Dennys" <gowron35@...> wrote:
> Never would have guessed that my question would have triggered such a
> By the time I get my new camera, we surely will have reached a
> Clear skies to all!
- View SourceLol, 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.
- View SourceHi 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
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
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. :-)