Archived posting to the Leica Users Group, 2019/06/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]You?re welcome! Please post your results. ?howard > On Jun 17, 2019, at 1:50 PM, Adam Bridge via LUG <lug at leica-users.org> > wrote: > > This was really useful fo rme, Howard. Thank you! With Jupiter so bright > in our sky right now I?m thinking it?s time to give this a shot. > > Adam > >> On 2019 Jun 17, at 8:20 AM, Howard L Ritter Jr via LUG <lug at >> leica-users.org> wrote: >> >> That?s a pretty good image for the lens, Peter, and some optimization >> would make it even more impressive. >> >> In your shot, the relatively small image size of the moons, which are >> effectively point sources at this FL, suggests that you could capture >> Jupiter's atmospheric cloud bands if you avoid the overexposure of this >> image. In photographing the rich but low-contrast detail in the >> atmosphere, overexposure is your enemy. Underexposure, with enhancement >> in post-exposure processing, can record nice detail, while overexposure >> that saturates anything more than a few of the brightest pixels >> irretrievably obliterates detail. You might try it again at 1/30 and >> shorter, and play with the result in PS Camera Raw, especially the >> exposure, contrast, clarity, and dehaze sliders. You might lose the moons >> at optimal exposure for the atmosphere, but you could do a composite >> image. >> >> And of course the sweet spot for resolution is somewhere between wide >> open, where diffraction-limited resolution is best but aberrations can >> occur, and fully stopped down, where aberrations are negligible but >> diffraction-limited resolution is worst. If you can find >> resolution-vs-aperture data for this lens, that might guide you. At f/11, >> the effective aperture of a 300-mm lens is just over 1 inch, which by the >> Rayleigh criterion has a resolving power of about 4.5 seconds of arc. >> (The angular diameter of the Galilean moons is about 1 arcsec, and of >> Jupiter, currently at opposition, about 45 arcsec.) You might experiment >> with larger apertures once you?ve found the optimal exposure time at >> f/11. If your lens goes to f/5.6, you could double your resolution ? even >> if that?s wide open, the aberrations might affect mostly the off-axis >> portions of the image. >> >> Sorry if I?ve turned a trip to the playground into a regimented chore! If >> you try any of this, please post. If I ever get clear weather, I?ll put >> my M240 on my 155-mm f/7 apo refractor and see what I can get. >> >> ?howard >> >> >>> On Jun 17, 2019, at 5:06 AM, Peter Klein via LUG <lug at >>> leica-users.org> wrote: >>> >>> <https://www.flickr.com/photos/24844563 at >>> N04/48078173256/in/dateposted-public/> >>> >>> Jupiter and its four largest moons. E-M5 on tripod, my $30 bargain-bin >>> 300mm Soligor lens, 1/8 sec at f/11, 100% pixels. One could do better >>> with a telescope, but I thought it would be fun to see what I could get >>> with what I had on hand. Enjoy! >>> >>> --Peter >>> >>> >>> >>> _______________________________________________ >>> 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