Archived posting to the Leica Users Group, 2017/06/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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. > > >>>>> See http://leica-users.org/mailman/listinfo/lug for more > information > > >>>> > > >>>> > > >>>> _______________________________________________ > > >>>> Leica Users Group. > > >>>> See http://leica-users.org/mailman/listinfo/lug for more > information > > >>> > > >>> _______________________________________________ > > >>> Leica Users Group. > > >>> See http://leica-users.org/mailman/listinfo/lug for more information > > >> > > >> _______________________________________________ > > >> Leica Users Group. > > >> See http://leica-users.org/mailman/listinfo/lug for more information > > >> > > > > > > _______________________________________________ > > > Leica Users Group. > > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >