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-   General photography discussion (http://e-group.uk.net/forum/forumdisplay.php?f=75)
-   -   Milky Way (http://e-group.uk.net/forum/showthread.php?t=48142)

chris 26th June 2018 08:54 PM

Re: Milky Way
 
The bit i'm not entirely sure on is knowing where to point the camera! Generically south, but is it obvious to the naked eye in a dark enough area? I have downloaded a night sky app to my phone to help!

Ian 26th June 2018 09:09 PM

Re: Milky Way
 
Quote:

Originally Posted by chris (Post 449790)
The bit i'm not entirely sure on is knowing where to point the camera! Generically south, but is it obvious to the naked eye in a dark enough area? I have downloaded a night sky app to my phone to help!

If you can't detect it with the naked eye I would think it's probably not going to photograph well - but those more experienced than me can comment more authoritatively.

Ian

Ian 26th June 2018 09:18 PM

Re: Milky Way
 
Nobody has mentioned the 500 rule. This calculates the maximum exposure time before the Earth's motion starts to turn the star points into little trails. For a 17mm lens you need to double to make 34 (full frame mm equivalent) and then divide 500 by it. Rounding up, that's a maximum of 15 seconds.

Actually, for Micro Four Thirds you can make it the 250 rule and there is no need to compensate for the crop factor, just divide the focal length (17) into 250.

For a 9mm super wide you can expose (250 divided by 9) for 28 seconds.

The longer the exposure the better of course and this is one reason why a moderate wide angle like a 17 isn't ideal for milky way shots, apart from the fact that it doesn't cover enough of the sky.

Ian

MJ224 26th June 2018 09:24 PM

Re: Milky Way
 
All good god photos, but my favourite is the last one with the red sun/moon/light pollution....*chr

wornish 26th June 2018 09:25 PM

Re: Milky Way
 
The 500 rule is a good guide elongated stars are not pretty.

BUT if you set your ISO high enough then you will be amazed at what you camera can capture in under 20 secs. Certainly more than the naked eye.

If you look the at link in my post #2 it shows you whats possible.

Not sure what phone you have but Celestron do some free software called Sky Portal which is very good. Highly recommended. It works on Android phones, apple phones and iPads.
It certainly will help you in deciding where to point.

https://www.celestron.com/pages/sky-portal-mobile-app

chris 26th June 2018 10:11 PM

Re: Milky Way
 
Quote:

Originally Posted by Ian (Post 449792)
Nobody has mentioned the 500 rule. This calculates the maximum exposure time before the Earth's motion starts to turn the star points into little trails. For a 17mm lens you need to double to make 34 (full frame mm equivalent) and then divide 500 by it. Rounding up, that's a maximum of 15 seconds.

Actually, for Micro Four Thirds you can make it the 250 rule and there is no need to compensate for the crop factor, just divide the focal length (17) into 250.

For a 9mm super wide you can expose (250 divided by 9) for 28 seconds.

The longer the exposure the better of course and this is one reason why a moderate wide angle like a 17 isn't ideal for milky way shots, apart from the fact that it doesn't cover enough of the sky.

Ian

Thanks Ian, I was aware of the 500 rule and as you say, had calculated 15 seconds for my 17mm. Although I am on the lookout for a used 12-40 2.8 pro, so if i get one of those I can be upto 21 seconds at 12mm :)

Graptolite 26th June 2018 10:28 PM

Re: Milky Way
 
I've spent quite a bit of time trying to get good Milky Way photos with EM1.2 and never really been very satisfied, and I'm lucky enough to live somewhere with very low light pollution.This is fairly typical of what I've managed to get in a single exposure (this was taken in December - it never gets dark enough at this time of year for us to see the Milky Way. The wrinkly appearance of the sky is due to the phenomenon of air glow - it's relatively uncommon to see it as clear as this) )
EM1.2, 7-14mm Oly at 7mm, 30s f2.8 ISO 6400:

https://farm2.staticflickr.com/1767/...69ce7fef_b.jpgMilky Way and airglow, Mochrum Loch by DavidMB2006

https://farm2.staticflickr.com/1764/...fc03bda2_b.jpgP116926 by DavidMB2006

I think you do need a bigger sensor to really get the detail, or possibly I'll need to have a good look at image stacking, which I've not yet tried.

Ian 27th June 2018 06:59 AM

Re: Milky Way
 
David, what were your settings (no exif data in your shots)?

Ian

wornish 27th June 2018 07:12 AM

Re: Milky Way
 
Quote:

Originally Posted by Graptolite (Post 449801)


I think you do need a bigger sensor to really get the detail, or possibly I'll need to have a good look at image stacking, which I've not yet tried.

When the air glow is there it will still show on a shot made using a full frame sensor, plus you won't get any more detail. To get more detail needs longer exposures at a given ISO, thats when astrophotography starts to hurt your wallet!

I assume the airglow is constantly changing so stacking a few shots taken at say 5 minute intervals may help as long as you align them first. Many photo applications can do this for you.

chris 27th June 2018 08:08 AM

Re: Milky Way
 
Whatched a tutorial on a free Milky Way stacking program called Sequator, looks user friendly with good results.

Graptolite 27th June 2018 08:29 AM

Re: Milky Way
 
Quote:

Originally Posted by Ian (Post 449811)
David, what were your settings (no exif data in your shots)?

Ian

The settings are in my post just above the first photo Ian.

Ian 27th June 2018 09:12 AM

Re: Milky Way
 
Quote:

Originally Posted by Graptolite (Post 449821)
The settings are in my post just above the first photo Ian.

Ooops, sorry - didn't notice that :)

Ian

Ian 27th June 2018 09:17 AM

Re: Milky Way
 
Can I presume that David's shots (which I would have been quite pleased with :)) were despite less than perfectly ideal conditions, meaning there is still more potential?

I can see some star elongation and I actually wonder if the focus is very slightly out?

Ian

chris 27th June 2018 09:31 AM

Re: Milky Way
 
Quote:

Originally Posted by Ian (Post 449826)
David's shots (which I would have been quite pleased with)

Ian

Id be over the moon 🌛if I come out with anything even remotely approaching those.

Graptolite 27th June 2018 01:44 PM

Re: Milky Way
 
Quote:

Originally Posted by Ian (Post 449826)

I can see some star elongation and I actually wonder if the focus is very slightly out?

Ian

Focus could well be slightly off - it's always a problem at night. I usually manually focus to the infinity sign on the focus ring and hope that with the wide angle lens there's enough dof to give me some leeway. Star elongation due to exposure length is usually more noticeable at the corners.


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