[Leica] IMG: Testing SL For Milky Way Imaging

Thu Jun 22 14:55:45 PDT 2017

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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> >>>>
> >>>>
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