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