Author Topic: Astro Photography  (Read 10319 times)

Re: Astro Photography
Reply #15 on: March 21, 2013, 22:10:33 PM
M3ta7h3ad, I've just had a look on YouTube and there's a LOT of astro photography vids on there, can't see the wood for the trees if I'm honest. Do you have a link to the one you're talking about? it sounds really interesting.

This one: http://youtu.be/11d-JbxXGAA

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Re: Astro Photography
Reply #16 on: July 30, 2013, 13:28:20 PM
I'm off to Wales on Thursday, back early on Sunday. Camping down near St. Davids, so hopefully if the sky is clear, light pollution shouldn't be too bad.

Not sure between going telephoto or wide angle. Will probably do both, using deep sky stacker to stack a mega load of images together. I've worked out my f1.8 40mm would be good for up to 10s exposures, so 100 exposures = 16 minutes. Not much I guess, but it'll be a warm up for going to Yorkshire the week after.

Redundancy is fun!

Re: Astro Photography
Reply #17 on: July 30, 2013, 21:48:43 PM
I recommend the restraunt in porthgain if your out that way.
Porthgain is worth a trip even if your not hungry.

Re: Astro Photography
Reply #18 on: July 30, 2013, 22:18:46 PM
I'm off to Wales on Thursday, back early on Sunday. Camping down near St. Davids, so hopefully if the sky is clear, light pollution shouldn't be too bad.

Not sure between going telephoto or wide angle. Will probably do both, using deep sky stacker to stack a mega load of images together. I've worked out my f1.8 40mm would be good for up to 10s exposures, so 100 exposures = 16 minutes. Not much I guess, but it'll be a warm up for going to Yorkshire the week after.

Redundancy is fun!

Do both but it depends what your after, wide angle is great for getting some foreground interst in or leading lines or something like that, but with telephoto you can concentrate on one particular star cluster or something.  With either from larger the apperture the better so your 40mm will be good if a little bit in the middle focal length wise.

I've never managed to get something stacked with DSS so it'll be interesting to see what you can come up with, I remember watching a video where someone said you do 600/focal length to get the number of seconds before you start to see star trails so you should get 15s but your better off playing around with it when you get there.

Good luck with focusing as well, you don't need the stars 100% in focus for something like a star trails shot but if your not after trails its a bit awkward, live view is your friend but again the larger the aperture the better as it lets more light in, I usually struggle with my 10-20mm at f4 but never tried it on anything better.

Erm can't really think of too much else other than maybe make sure your phones for plenty of charge so you can play around on it whilst you wait around.

Re: Astro Photography
Reply #19 on: August 07, 2013, 19:12:34 PM
without a driven mount, it'll be a LOT easier to get deep sky objects with the 40 1.8 than a telephoto. Two reasons for this:

1. wider angle lets you use longer individual exposures

2. f/1.8. I don't know what teles you have available, but that's a good stop faster than the fastest long lens I know of, and 2 or more stops faster than most.

This adds up to a lot more light gathering per frame. This is important because although you'll be using stacking to bring out the faint objects, you still need there to be SOME difference between object and non-object pixels. Exposure stacking is a great tool, but like most post processing it has limitations compared to gathering the photons in one big go.

The Milky Way makes an exciting target for shortish exposures with foreground interest

Pick your targets carefully, some deep sky objects are actually HUGE and you don't really need a telephoto to photograph them. The great nebula in Orion and the Andromeda galaxy leap to mind. Both are larger than the full moon, the Orion nebula quite a lot larger.

You'll also want to consider a dark frame. My camera does dark frame subtraction by default on long exposures, but that doubles the length of acquisition as it captures a second exposure of the same length with the shutter closed. I usually turn this option off and use a separate dark frame taken with the lens cap on. That way I only have to take one per length of exposure/ISO combination I'm using. I assume you're shooting raw, if your usual raw converter doesn't support dark frame subtraction, I have previously used UFRAW for this purpose, and it now appears Rawtherapee also supports it with the latest version, although I haven't tried that yet.

good luck and have fun
Last Edit: August 07, 2013, 19:19:06 PM by Mongoose #187;

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Re: Astro Photography
Reply #20 on: August 07, 2013, 21:27:29 PM
Wales was a blowout due to clouds. Yorkshire tomorrow though for a few days, down by a resevoir, so some good sunset shots, and maybe astro stuff then.

Photos from Wales:

http://www.flickr.com/photos/zpyder/sets/72157634957187426/


B20.jpg by Chris_Moody, on Flickr


Sunset 3.jpg by Chris_Moody, on Flickr

Re: Astro Photography
Reply #21 on: August 07, 2013, 22:50:29 PM
washout for astro  maybe, but the landscapes turned out pretty good, and the clouds make the sky more interesting so not all bad!

Re: Astro Photography
Reply #22 on: August 12, 2013, 13:51:35 PM
Yeah first ones not bad but maybe boost the contrast in the sky to darken it down a bit, make it more moody and at the same time give it a bit of definition between the sky and the ground?

The 2nd one's foreground is good just a shame the suns blown well out, clouds look cool to the left of it though.  Have you done that as HDR?

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Re: Astro Photography
Reply #23 on: August 12, 2013, 20:15:38 PM
HDR + ND Grad. Still learning the ropes with Photoshops "Merge to HDR Pro" tool. I'm thinking the second one would have worked better as two separate HDRs, (sky+sun, and sea and rocks) layered and masked together. I just couldn't seem to get the sky "right" without the sun getting washed out.

Re: Astro Photography
Reply #24 on: August 12, 2013, 20:27:24 PM
HDR + ND Grad. Still learning the ropes with Photoshops "Merge to HDR Pro" tool. I'm thinking the second one would have worked better as two separate HDRs, (sky+sun, and sea and rocks) layered and masked together. I just couldn't seem to get the sky "right" without the sun getting washed out.

Its difficult shooting into the sun, I often try it with some of my shots and they just look a bit wrong at times, in some ways I have no idea how some people manage it tbh, more practice is required me thinks!  But I think if you'd waited around for another 20 mins until the sun had actually set it'd drop in intensity and the DR between the sea and the sky would have lessened to such an extent it wouldn't have blown out.

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Re: Astro Photography
Reply #25 on: August 13, 2013, 09:09:39 AM
Yeah, I hung around for 10-20 minutes until pretty much any colour had disappeared from the sky. On the walk back I realised I'd have been better off photographing away from the sun as the cliffs were still fairly lit up and colourful, oh well!

One thing I'm noticing is that when I've got several HDR shots from the same "set", If I flickr through shot 1, shot 2, shot 3 etc, I think they improve, either due to the light being better, or just the fact that I've progressively tweaked the HDR settings!

Re: Astro Photography
Reply #26 on: August 13, 2013, 21:03:54 PM
Yeah, I hung around for 10-20 minutes until pretty much any colour had disappeared from the sky. On the walk back I realised I'd have been better off photographing away from the sun as the cliffs were still fairly lit up and colourful, oh well!

One thing I'm noticing is that when I've got several HDR shots from the same "set", If I flickr through shot 1, shot 2, shot 3 etc, I think they improve, either due to the light being better, or just the fact that I've progressively tweaked the HDR settings!

I seem to remember some tip I heard years ago before I even got in photography saying you should have the sun over your shoulder, can't remember the anything more than that so could have been for a different aspect of photography but I guess it works to a certain degree.  Thing is most of the colour & contrast is if you shoot in the rough direction of the sun or at least in the same 180 degrees as it anyway.

It could be the light getting better, after a few minutes it can change loads so will be enough to register but like you say could be your just getting better at tweaking the shots as you go could be hard to tell tbh!

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Re: Astro Photography
Reply #27 on: August 17, 2013, 14:31:07 PM
Girlfriend went out with friends last night and I was the taxi. Ended up getting back home at about 2-2.30. Around here they turn the streetlights off after midnight, I was surprised by how dark it was. Still enough light pollution, but I guess it's a good way to practice technique instead of wasting a trip out somewhere more remote


Astro by Chris_Moody, on Flickr

Re: Astro Photography
Reply #28 on: August 22, 2013, 21:41:59 PM
Just had a look on flickr and that was a stacked shot?  If so can you give a bit of info on what you took etc, not managed to get a stacking shot to work yet but I'll be trying again later this year hopefully.

Full size it looks like the stars are a little out of focus, or could be the start of some trails but full size you see just how many stars you've managed to get so even if there was a bit of light pollution its come off nicely.

I'd love to get myself something like a Tokina 11-16 f2.8 to get more star stuff, should be getting a 17-50 f2.8 in a few months so that'll have to do for now.

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Re: Astro Photography
Reply #29 on: August 23, 2013, 19:54:18 PM
Stacked shot. 15 light frames 5 dark.
 
Manual mode. F2.8. ISO 1600. 17mm. 20 second exposures. I couldn't be arsed working out the 400/17 so assumed it'd be close to, or slightly above 20 seconds for exposure before star trails. I also used a radio remote control to take the shots (I think if I do this again I'll hook up the tablet computer to the camera and use an app to just interval shoot).

I used deep sky stacker and the RAW files. Pretty much just loaded the light and dark frames and then just processed it as was. I then used Adobe CameraRaw to post process a tad to adjust contrast and colour a bit.

The stars are likely out of focus as I couldn't really tell whether it was in focus due to light. I also recalled something about you don't focus to the limits of the infinity distance, so I focused as far as I could, and then tweaked it back a fraction. Probably a mistake!

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