Archived posting to the Leica Users Group, 2017/06/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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 >