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