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10-03-2013, 10:28 PM   #1
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Beginners astrophotography with the K-30

I have successfully managed to take several sessions of interval photography of the sunset and night sky. It took a bit to work out a higher ISO is a grainer picture. Even with "town" light pollution I can see the milky way in the pictures. See my upload in the welcome forum.

For the night, I am experimenting with ISO 3200, F3.5, Lens 18mm and an interval of 20 secs every minute. I have both Shake Reduction and Noise Reduction on. From what I see in this forum, people advise to have these two off and do "comparison" pictures with the lens cap on to get rid of "noise". Isn't this what Noise Reduction does? As long as "more than twice the exposure time fits into the interval time" there should be enough time for both these settings on.

I do have another fairly basic question though. With Autofocus off, how do I focus the K-30 at night, pointing to a dark sky? So far, I've done nothing except switch the AF.S/C/MF to the MF setting.

10-04-2013, 01:12 AM   #2
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You should definitely turn SR off, as you will have no camera movements on a stable tripod. With SR on and no movements to counter, your system might interpret the inevitable electrical noise in any circuit as a genuine signal and try to compensate for a movement that isn't there - making images more and not less blurred!

Most of us turn Dark Frame Subtraction off because it is a time consuming process. We want many exposures and fewer dark frames. If you are setting out to shoot about a hundred images in a session, you will soon learn why. Likewise, if you plan to shoot star trails, you don't want 20 second gaps between your star trail images.

Regarding focus, AF will probably not work with an 18mm lens at f/3.5. But seek out some of the brightest stars - or the Moon, if it is up - and use live view at the highest magnification (8X for a DA lens; 10X for a manual lens) to focus them manually and then leave the settings there, checking once in a while that nothing has accidentially changed over the course of time. Before I got live view, I used a right angle view finder with 2X magnification which was also very helpful - and actually very good for my neck whenever I would focus on something higher up in the sky.
10-20-2013, 02:26 AM - 3 Likes   #3
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Hey! Good to "meet" another Pentax (K-30, even)-using astrophotographer.

This was my first crack at the Milky Way with my K-30:

Milky Way edit #7 by -Occasionally Focused-

And the second, which is my favourite so far (only a smallish pic; I had to retrieve it from 500px, and for some reason only a smaller file is there - bigger one will be on my computer):

Milky Way 8.10.13 by -Occasionally Focused-

These are both single shots. Tripod (obviously); aperture wide-open; manual focus, with some test shots to get the focus right; rule of 600 (600 divided by effective focal length of your lens is the longest exposure you can have before you get trailing of stars); noise reduction on; shake reduction off. These were with ISO of 3200, and a shorter exposure time than the maximum (8" for the first, and 10" for the second). Next time I try (once these damn bushfires finish and the air clears ... that'll be a while) I'm going to increase the exposure time a little and try ISO 1600 instead.

And after that the plan will be for a wider-angle lens, both for the wider view, and for the longer exposure time it'll allow.

I would recommend you follow Michael Shainblum on Google+ or Farcebook [sic], and check out his great tutorials on post-processing for the Milky Way:
and
The right post-processing really is important.
10-23-2013, 05:13 AM   #4
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I tried last weekend I didnt get much with my K30. Because of light pollution.

I see electric lines and trees? Were you in the city?

10-23-2013, 06:18 AM   #5
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Peter, welcome. You're off to a good start.

Focus: Use liveview and manually focus on a bright star, then zoom in by pressing the Info button to finetune focus. If there's no bright star where you want to take your picture you can focus using a different part of the sky.

Noise Reduction: I use the long exposure NR when I'm taking only a few images. Turn off NR if you are taking a star trail or timelapse because you don't want gaps between photos. In-camera NR also drains the battery twice as fast.

Also turn off NR if you are "stacking", a more advanced postprocessing routine. With stacking you take many photos of the same part of the sky, then combine them into a single image later. A stack of 32 images can use only 4 or 8 dark frames, so manually taking dark frames instead of waiting for in-camera NR on 32 photos saves time.

Having said all that, there are many different astrophotography approaches. In the end you might find that using in-camera NR works well for you.
10-23-2013, 11:22 PM   #6
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QuoteOriginally posted by Culture Quote
I tried last weekend I didnt get much with my K30. Because of light pollution.

I see electric lines and trees? Were you in the city?
In the lower Blue Mountains, west of Sydney. We're really rather fortunate that only 20 minutes from a large bit of city (Penrith) we actually have relatively dark skies. Not as dark as they could be (and the last week they've been filled with smoke...) Next thing is to head further up and out, to really dark sky.

... After the bushfires are out, that is
10-24-2013, 03:01 PM - 3 Likes   #7
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Took that over Christchurch with the K-30 using sigma 10-20mm stitched 3x images. Aurora is what gives the lower section that pink and orange glow.



same night:



and a different outing, the lights are from a port.



I also have the astrotracer, I must get out more. The K-30 is definitely able to capture some astro stuff if the conditions are right.
10-24-2013, 04:21 PM   #8
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QuoteOriginally posted by FruitLooPs Quote
Took that over Christchurch with the K-30 using sigma 10-20mm stitched 3x images. Aurora is what gives the lower section that pink and orange glow.



same night:



and a different outing, the lights are from a port.



I also have the astrotracer, I must get out more. The K-30 is definitely able to capture some astro stuff if the conditions are right.
All fantastic photos. Great work - I especially like that Milky Way with the aurora glow. Fabulous!

01-10-2014, 03:35 PM   #9
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Hey guys, anyone gonna welcome me to the club?
With such a learning-curve, in two months, I've only scraped the surface on what kit and PP methods to use.
Well, I'm glad I found this thread!!
Please, if you'd be so kind indulge me with your latest results?
Coincidentally I've processed two images on DSS. I'm going to read through the tutorial more slowly and try another image. I'm still sifting through what bias and flats in DSS are. :S
Anywho, I've got my K30 and out of my lenses I'm using a Sigma 50/1.4, a FA100/2.8Macro, a SMC M-85/2 (haven't tried it yet).
I'd say I'm on target as my images look pretty bad but you guys are gonna lift my spirits and give me some hope by showing me how great I'll be (like you guys) in no time, right? right?? RIGHT???!!!

Last edited by Iksobarg; 01-10-2014 at 03:36 PM. Reason: grammar
01-25-2014, 09:16 PM - 1 Like   #10
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Here's my latest, using the astrotracer mode in the O-GPS:

Snell's Beach Starscape 21st January by -Occasionally Focused-

Still coming to grips with it, but very pleased so far.
01-25-2014, 09:17 PM   #11
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QuoteOriginally posted by Iksobarg Quote
Hey guys, anyone gonna welcome me to the club?
With such a learning-curve, in two months, I've only scraped the surface on what kit and PP methods to use.
Well, I'm glad I found this thread!!
Please, if you'd be so kind indulge me with your latest results?
Coincidentally I've processed two images on DSS. I'm going to read through the tutorial more slowly and try another image. I'm still sifting through what bias and flats in DSS are. :S
Anywho, I've got my K30 and out of my lenses I'm using a Sigma 50/1.4, a FA100/2.8Macro, a SMC M-85/2 (haven't tried it yet).
I'd say I'm on target as my images look pretty bad but you guys are gonna lift my spirits and give me some hope by showing me how great I'll be (like you guys) in no time, right? right?? RIGHT???!!!

Welcome

I can't find a stacking app for Mac, so I'm stuck with single exposures, and trying to improve them.
01-25-2014, 10:10 PM   #12
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Tsuken - Check this thread out.

best astrophotography software: Mac Talk Forum: Digital Photography Review

Jack
01-26-2014, 01:38 AM   #13
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QuoteOriginally posted by jbinpg Quote

Thanks for that 8)
01-26-2014, 10:41 AM   #14
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Sorry, thought I found the answer and didn't.
Question: Firsthand experiences with how Astrotracer fares at long exposures (30 secs, 3 mins, 5 mins?) @ 200mm or more?

I did find this: http://www.dpreview.com/forums/thread/3060089

Of course, I've come to learn that getting the exposures is only the beginning.

Next question:
Is there a best reasonable and/or budget friendly alternative to Photoshop?
I've read that GIMP doesn't process/edit 16 bit, um, images, that Photoshop and other(?) more premium softwares do.
SilkyPix???
02-02-2014, 05:54 AM   #15
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What I tend to do it shoot off a couple of pictures on a high ISO to check the compositon and the focus as I find with the k-30 neither the viewfinder or the liveview mode allow me to easily check focus.

I then wind back the ISO to 400 or less and shoot multiple images with anything from one to 10 second exposures (anything more and the stars usually begin to trail). I then use the DeepSkyStacker program to stack the images together. This really helps cut down the noise and allows you to filter out the light pollution by taking both a flat field (pointat sky and defocus) and a dark image.

I know the qulaity isn't great as I haven't had time to really clean up the image and there was a lot of light pollution, but this is about 80 stacked photos of 10 seconds each and shows the Andromeda galaxy as it might appear to the naked eye in good visibility. So there is lot that can be done with clear skies, software, and patience !
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