Archived posting to the Leica Users Group, 2019/06/17

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Subject: [Leica] IMG: Galileo was right
From: abridge at (Adam Bridge)
Date: Mon, 17 Jun 2019 10:50:22 -0700
References: <> <>

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.


> On 2019 Jun 17, at 8:20 AM, Howard L Ritter Jr via LUG <lug at 
>> 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> 
>> wrote:
>> < 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
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Replies: Reply from hlritter at (Howard L Ritter Jr) ([Leica] IMG: Galileo was right)
In reply to: Message from boulanger.croissant at (Peter Klein) ([Leica] IMG: Galileo was right)
Message from hlritter at (Howard L Ritter Jr) ([Leica] IMG: Galileo was right)