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Re: [APML] Possible Fake or Worse??
Thanks for the kind words Bert and Jerry.
Stephen, have you been using raw format to capture your 10D images? Before
any processing you would then convert them to 16-bit TIFF using linear mode
so that no processing is done on the image data by the camera. This is a
very important step and leads to greater bit depth and control over
calibration thus smoother images. Here is an example that was posted on
Yahoo Digital_Astro last week:
"Canon DSLR cameras allow you to store a raw image with 12-bit
precision and without any extra processing. Raw format allows direct
access to the raw image data in 12-bit precision. If an image is
saved by the camera in JPEG or TIFF format then standard brightness
increase, sharpening, and other functions are applied and the result
is stored in 8-bit precision. The problem with JPEG and TIFF is lost
image data from 8-bit precision and JPEG compression and noise is
stretched before it can be removed. It is much better to remove as
much noise as possible using dark frames and stacking methods before
the image is stretched. Raw format allows you to convert an image to
16-bit TIFF using linear mode so that none of the 12-bit precision is
lost and no processing is performed.
Raw images of deep sky objects converted to 16-bit TIFF using linear
mode are dark. Here is an example of 10 5 minute exposures stacked
but with no additional processing. The image is very dark:
M27 with Canon 1Ds and 180mm TMB at F9:
http://www.mlunsold.com/examples/Temp/M27Step1Crop.jpg
The result of digital development applied to the same image:
http://www.mlunsold.com/examples/Temp/M27Step2DDP.jpg
An extreme brightness increase is possible since most of the noise
was removed by adaptive dark frame calibration and excluded min/max
averaging before digital development.
The same holds true for images from a cooled CCD. 16 10 minute
exposure of M27 with an H-alpha filter were processed the same as above.
M27 with ST-10XME, H-alpha filter, 180mm TMB at F9:
http://www.mlunsold.com/examples/Temp/M27_160mHaRaw.jpg
After digital development brightness boost:
http://www.mlunsold.com/examples/Temp/M27_160mHaDDP.jpg
"
Have a nice day.
Mike
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>
----- Original Message -----
From: "Stephen Pitt" <lthuedk@pe.net>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Tuesday, September 02, 2003 2:27 AM
Subject: Re: [APML] Possible Fake or Worse??
> Mike, as you can imagine, I struggled with PS7 and Registar alone on
> this. Yes, the processing was way too tedious. Even the Canon software
> seemed sluggish. Correct, I stacked two dark frames after getting their
> values as close to the light frames as possible, then used layers and
> differences, with sliders to adjust the level of subtraction. And, as a
> filmer, I have some experience in aggressive stretching.
>
> Nothing can replace more frames though. So, first thing next new moon.
> And on the 15th, I need to do business with you.
>
> Best regards,
>
> Stephen Pitt: http://www.light-to-dark.com/
>
> Mike Unsold wrote:
> > The M31 image is certainly within the capability of the 10D. Actually an
> > averaged dark frame used with adaptive dark frame subtraction followed
by a
> > sigma clipped or excluded min/max average combination would yield a very
> > smooth stacked image that could be aggressively stretched.
> >
> > Here are some additional examples using the D60 and 1Ds. Exposure and
> > processing detail is available under each image.
> >
> > http://www.mlunsold.com/examples/D60/D60-M31.html
> >
> > http://www.mlunsold.com/examples/1DS/1Ds-M22.html
> >
> > http://www.mlunsold.com/examples/D60/D60-NGC891.html
> >
> > (click on the image for a larger version)
> > http://www.mlunsold.com/examples/1DS/1Ds-M27.html
> >
> > Mike
> >
> >
> > ----- Original Message -----
> > From: "Jerry Lodriguss" <jerry@astropix.com>
> > To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> > Sent: Monday, September 01, 2003 10:57 PM
> > Subject: Re: [APML] Possible Fake or Worse??
> >
> >
> >
> >>I don't know why you would doubt the integrity of this photo, especially
> >>based on the outstanding quality of work that Stephen has produced
> >
> > previously.
> >
> >>Lots of people have shot long-exposure deep-sky shots with a Canon 10D,
> >
> > D60
> >
> >>and even the 1Ds, so there is nothing out of the ordinary about this
photo
> >>being taken with that camera and a CMOS chip.
> >>
> >>See:
> >>
> >>http://www.ricksastro.com/Gallery/htm/10D.htm
> >>
> >>And:
> >>
> >>http://velatron.com/dca/gallery/
> >>
> >>And:
> >>
> >>http://www.mlunsold.com/ILExamples.html
> >>
> >>Jerry
> >>
> >>
> >>
> >>>Could this be true??
> >>>Mr. Pitt says this is his photo of M31 on a CMOS 10D Digital Camera???
> >>>I seem to recognize this photo?????!!!!!!
> >>>Any help with this from the group??
> >>>Ray Rochelle
> >>>
> >>>----- Original Message -----
> >>>From: "Stephen Pitt" <lthuedk@pe.net>
> >>>To: <digital_astro@yahoogroups.com>
> >>>Sent: Monday, September 01, 2003 2:38 PM
> >>>Subject: [digital_astro] Testing the Digital Waters
> >>>
> >>>
> >>>
> >>>>This is my first image post using a digital anything,
> >>>>
> >>>>http://www.light-to-dark.com/m31_10D.html
> >>>>
> >>>>and I have found the 10D to be quite a challenge, with a fresh set of
> >>>>ideosyncrasies to deal with, like noise, uneven field colour
> >>>>temperature (possibly heat from the electronics), and vivid background
> >>>>colour pixellation. The processing is at least as challenging as that
> >>>>of film and its easy understand the need for dedicated software that
> >>>>could make stacking and dark frame subtraction less labor intensive.
> >>>>
> >>>>Admittedly, I got the 10D hoping for a panacea, a short cut to quick
> >>>>imaging, but find such things as noise reduction-like SBGNR-more of a
> >>>>necessity than an occasional luxury. But then, I'm not used to
> >>>>stacking more than 2 or 3 film images and ending up with smooth
> >>>
> > pictures.
> >
> >>>>Anyway, the chip is challenging. I can't help but wondering about
> >>>>cooling effects on image quality. Perhaps, when winter comes, the
> >>>>CMOS will be more image friendly, as ambients of 72-75 deg., such as
> >>>>those during the above acquisition seem to be quite noisy.
> >>>>
> >>>>All of this is to say, I have come to respect the work done by others
> >>>>using their digital cameras. And, I have to ask: Would such programs
> >>>>like I.P. make more efficient use of time in processing the images
> >>>>than say, P.S. and RegiStar?
> >>>>
> >>>>Thanking you for a reply,
> >>>>
> >>>>Stephen: http://www.light-to-dark.com/ iew my Photos go here
> >>>
> >>>http://www.usefilm.com/browse.php?mode=port&data=17313
> >>>Dance like no one's watching
> >>>Love like you've never been hurt before
> >>>Live like heaven is here on earth
> >>>121.80/39.75
> >>>Ray Rochelle
> >>>
> >>>
> >>>_______________________________________________
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> >>>Astro-Photo@seds.org
> >>>http://seds.org/mailman/listinfo/astro-photo
> >>
> >>
> >>Photoshop for Astrophotographers - http://www.astropix.com/PFA/PFA.HTM
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
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> >>
> >>
> >
> >
> >
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