[Leica] IMG: Testing SL For Milky Way Imaging

Robert Adler rgacpa at gmail.com
Thu Jun 22 17:35:55 PDT 2017 

Well it's gorgeous! Hope it's on a wall...


Bob Adler
www.robertadlerphotography.com
*"Capturing Light One Frame At A Time"*

On Thu, Jun 22, 2017 at 2:55 PM, Gene Duprey <geneduprey2015 at gmail.com>
wrote:

> This was my first using long exposures.  And pretty much my first
> successful pano.
>
> Gene
>
> On Thu, Jun 22, 2017 at 4:16 PM, Bob Adler <rgacpa at gmail.com> wrote:
>
> > Ah. Didn't get that it was multiple shots totaling 20minutes. I haven't
> > tried panos yet.
> >
> > Bob Adler
> > www.robertadlerphotography.com
> >
> > > On Jun 22, 2017, at 1:15 PM, Gene Duprey <geneduprey2015 at gmail.com>
> > wrote:
> > >
> > > Hi Bob,
> > >
> > > I am using a 15mm lens and 30 sec. is good for no star trails.  I use
> 500
> > > as the numerator.  I use Sky Guide to see where it will be, but there
> are
> > > others.  I was out last weekend shooting the Milky Way and got some
> nice
> > > shots and did a pano of six frames.  I think this was at 25 sec.
> > >
> > > Leica Users' Gallery
> > > <http://gallery.leica-users.org/main.php?g2_highlightId=51631> » Gene
> > Duprey
> > > <http://gallery.leica-users.org/v/GRDuprey/?g2_highlightId=442261> »
> > > 20170616-_DSC0182-Pano
> > >
> > >
> > > Gene
> > >
> > >
> > >> On Thu, Jun 22, 2017 at 1:43 PM, Bob Adler <rgacpa at gmail.com> wrote:
> > >>
> > >> Hi Gene,
> > >> Thank you.
> > >> How do you prevent star trails with that long of an exposure? The
> normal
> > >> rule to prevent trails and keep the stars sharp is 500/lens focal
> > length (
> > >> I use 300 to 350 as the numerator). So using the SL 24-90 @ 24, I get
> a
> > >> maximum exposure time of 15. I used mostly 20sec on most of these,
> > though
> > >> one was 15sec.
> > >> Are you using a star tracker of some sort?
> > >>
> > >> Bob Adler
> > >> www.robertadlerphotography.com
> > >>
> > >>> On Jun 22, 2017, at 10:53 AM, geneduprey2015 at gmail.com wrote:
> > >>>
> > >>> I'm surprised you used such a high ISO. I have been using 3200 or
> 2400
> > >> with great results and between 25 & 30 seconds.  Great shot though.
> > >>> Gene
> > >>>
> > >>> Sent from my iPhone
> > >>>
> > >>>> On Jun 22, 2017, at 10:49 AM, Howard L Ritter Jr <hlritter at twc.com>
> > >> wrote:
> > >>>>
> > >>>> That’s a very nice capture of the region towards the center of the
> > >> Galaxy, Bob. And even expanding the image on my screen, I don’t see
> any
> > >> bothersome noise. There’s virtually none in the dark regions of the
> > hills,
> > >> and the mottling in the lake and the sky I think is primarily due to
> the
> > >> innumerable stars. In any case, the SL’s performance at ISO 12500 is
> > >> impressive. That region is my favorite binocular target, and now that
> > I’ve
> > >> discovered how to nearly eliminate the effects of light pollution in
> my
> > >> suburban sky, and begun to do sky imaging, it will be a target for
> that
> > as
> > >> well.
> > >>>>
> > >>>> I don’t recall whether you mentioned seeing them when I first posted
> > >> them, but I took some similar shots of the Southern Hemisphere Milky
> Way
> > >> from Australia in April. I took them with a Nikon D810A (the
> > >> astrophotography model with the less IR-restrictive sensor cover
> plate)
> > and
> > >> the Nikon 14-24mm zoom at 14mm or the 24-85mm zoom at 50 or 85mm. The
> > shots
> > >> with the zoom were done with the camera on a tracking device to avoid
> > star
> > >> trailing. I used ISOs of 1600-6400.
> > >>>>
> > >>>> http://gallery.leica-users.org/v/hlritter/Gallery_001/ <
> > >> http://gallery.leica-users.org/v/hlritter/Gallery_001/>
> > >>>>
> > >>>> I stretched the histogram of my images in PS by moving the
> white-point
> > >> slider to brighten the stars and the black-point slider to darken the
> > >> background sky, then fiddled with both, plus the grey-point slider, to
> > get
> > >> the effect I wanted. To get rid of vignetting, I also applied a
> > flat-field
> > >> correction frame that I took in daylight with a couple of layers of
> > white
> > >> T-shirt over the lens, and the camera aimed away from the sun at a
> > sunlit
> > >> scene, and then converted to greyscale. I think my images as posted
> are
> > a
> > >> bit hyper-real, but that’s a goal of photographing any celestial
> targets
> > >> other than the bright moon and planets. In any case, they carry the
> > flavor
> > >> of the visual impact of seeing the Southern Milky Way and the
> Magellanic
> > >> Clouds, for the first time, from the deep darkness of rural Australia.
> > The
> > >> left side of the region of the MW that I imaged adjoins on the right
> > your
> > >> region of the MW at the dense star cloud in the center of your first
> > image.
> > >> The very different orientation of the MW is what happens when your
> > >> viewpoint is rotated 65 degrees clockwise!
> > >>>>
> > >>>> Did you do any post-processing of these images? They have the look
> of
> > >> raw images to me. If so, I’d be interested to see what the result of a
> > >> histogram stretch might be. Would you mind sharing the raw file with
> me
> > so
> > >> I can play a little? I’ve added a couple of the raw images to my album
> > so
> > >> you can see the difference post-processing makes.
> > >>>>
> > >>>> It’s possible to see very short star trails by enlarging your
> images.
> > >> The rule of thumb is that they won’t be easily noticeable if the
> > exposure
> > >> time is not more than 300 sec divided by the FL in mm, so your 20-sec
> > >> exposures at 24mm are pushing it. If you’re going to do much of this
> > sort
> > >> of thing, a camera tracker can be had for about the price of 2 or 3 SL
> > >> batteries… 😉 Some of my images were exposed for longer than the rule
> of
> > >> 300, which is possible when the region being imaged is well away from
> > the
> > >> celestial equator, where the stars move fastest.
> > >>>>
> > >>>> (Pardon me if I’m telling you things you already know!)
> > >>>>
> > >>>> —howard
> > >>>>
> > >>>>
> > >>>>> On Jun 21, 2017, at 5:28 PM, Robert Adler <rgacpa at gmail.com>
> wrote:
> > >>>>>
> > >>>>> Last night I went up to Silver Lake in the Sierras. It's at about
> > >> 7,800'
> > >>>>> elevation. I went to see how the SL with the SL24-90mm would work
> > with
> > >>>>> Milky Way photography. The two images were taken at 12,500 ISO @
> > 24mm,
> > >>>>> f/2.8 with a 20second exposure. I shot from 10:30pm until 3:00am...
> > >>>>>
> > >>>>> Though there is a lot of noise, I don't find it distracting. The
> > drama
> > >> of
> > >>>>> the center of our galaxy seems to outweigh any noise issues. Please
> > >> click
> > >>>>> on the image to make it larger to fit your screen:
> > >>>>>
> > >>>>> http://www.robertadlerphotography.com/
> p133735760/h8e052599#h8e052599
> > >>>>>
> > >>>>> I would appreciate others' opinions as to whether or not they find
> > the
> > >>>>> noise distasteful or does it look more like film grain. The images
> > were
> > >>>>> post processed in Capture 1.
> > >>>>>
> > >>>>> Thanks for any opinions in advance,
> > >>>>> Bob
> > >>>>>
> > >>>>>
> > >>>>> Bob Adler
> > >>>>> www.robertadlerphotography.com
> > >>>>> *"Capturing Light One Frame At A Time"*
> > >>>>>
> > >>>>> _______________________________________________
> > >>>>> Leica Users Group.
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> information
> > >>>>
> > >>>>
> > >>>> _______________________________________________
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> information
> > >>>
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> > >>
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> > >>
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