Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-10-2016, 07:38 PM   #1
Site Supporter




Join Date: Jul 2016
Posts: 62
Capturing the Astro Trifecta Shot - Foreground + Milky Way + Meteor Shower

[Astrotracer can be set in any mode (software allows it), but it only effectively works in B (Bulb) mode (as stated above by Steve). In B mode, it is not possible to use the camera own intervalometer (I.e drive mode = INT), but, by pressing the green button we can set the duration of exposure with a dial wheel for up to 5 minutes. If more than one frame should be captured using an external intervalometer to trigger the shutter in B mode+astrotracer, I'm not sure if the stars would still be aligned when stacking multiple Astrotracer frames. However, regarding ISO and aperture settings, f4 ISO400 + 4 minutes exposure (<5 minutes) should work, or even f2.8 ISO200 (very clean) 4 minutes + low shutter speed noise reduction (dark frame subtraction), should deliver very clean images, so no frame stacking necessary to improve image quality. Without dark frame substration, at ISO200, the slow shutter speed noise only become visible beyond 10 minutes exposure, therefore, even with a slow lens (f4, f5.6), I believe it is possible to produce high quality Astrotacer images with the Pentax K1]


I am trying to produce a shot incorporating an interesting foreground, the Milky Way overhead, and the perseid meteor shower taking place.

Normally, with my precious Sony, I would take a series of short, maybe 15-20 sec milky way shots, and stack them. Then ai would focus of a very close foreground, usually with a 14mm or fisheye lens, and make that my foreground. then i would composite the two into a final image.

However, my new K-1 offers some new possibllities, considering Biz-engineer's comments above.

So, here is my current plan:

1) Capture my foreground shots.

2) I don't know how long I can run Astrotracer with a 14mm lens. I will experiment tonight to find out. I am thinking about 2 min exposures at f/2.8 at whatever ISO works to give me a skyglow about 1/3 of the histogram from the left. Since the camera is supposed to be ISO-invariant, it should not make that much difference.

3) Setup the intervelometer to run a bunch of these of several hours. If I am running dark frames for each shot, then I need to set the intervelomete for about 4.5 minutes becaus of:

2 min exposure + 2 min dark frame + processing + disk write

The intent is not to stack these various exposures, but to select the ones that have the most interesting meteor trails.

Does this setup make sense?

Tnk for any comments.

08-10-2016, 08:22 PM   #2
Pentaxian




Join Date: Jan 2011
Location: New York
Posts: 3,200
Consider turning off in-camera dark frame subtraction. You don't need that for every photo - it will waste time that could be better spent getting photos of meteors. If you fear your exposures will be too noisy, take a set of four manual dark frames at the end of your sequence (or in the middle if outdoor temperatures change a lot), then when processing average the dark frames, create a master dark, and subtract the master dark from your keeper light frames.
08-10-2016, 09:37 PM   #3
CDW
Veteran Member




Join Date: May 2011
Location: Big Island, Hawaii & Utah
Posts: 356
I've heard of a white spot issue on some Sony sensors. It shows up on my K1 on long exposures with what appears to be hundreds, if not thousands, of hot pixels. Turning on long shutter noise reduction seem to eliminate it. Nevertheless, so many 'defective' pixels is disturbing.
08-10-2016, 10:02 PM   #4
Site Supporter




Join Date: Jul 2016
Posts: 62
Original Poster
QuoteOriginally posted by DeadJohn Quote
Consider turning off in-camera dark frame subtraction. You don't need that for every photo - it will waste time that could be better spent getting photos of meteors. If you fear your exposures will be too noisy, take a set of four manual dark frames at the end of your sequence (or in the middle if outdoor temperatures change a lot), then when processing average the dark frames, create a master dark, and subtract the master dark from your keeper light frames.
yes, I was thinking about that as well. It is really a waste of precious imaging time. In addition, a stack of 4 or 8 dark frames will be lower noise than a single dark frame. It is easy tio subtract dark frames in DSS, but not sure how to do it in photoshop or lightroom.

08-10-2016, 10:12 PM   #5
Senior Member
Medex's Avatar

Join Date: May 2013
Posts: 204
QuoteOriginally posted by CDW Quote
I've heard of a white spot issue on some Sony sensors. It shows up on my K1 on long exposures with what appears to be hundreds, if not thousands, of hot pixels. Turning on long shutter noise reduction seem to eliminate it. Nevertheless, so many 'defective' pixels is disturbing.
Could you post picture with that hot spot? How long should be the exposure? Thank You
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
astro trifecta shot, astrotracer, dslr, exposure, full frame, full-frame, intervalometer, k-1, k1, minutes, mode, pentax k-1, trifecta shot foreground
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Meteor shower reminder. gifthorse General Photography 15 07-26-2016 06:17 PM
Night First ever try at capturing Milky Way voy-tech Photo Critique 9 09-30-2015 09:32 PM
Night 2015 Perseid Meteor Shower. uday029 Post Your Photos! 2 08-31-2015 03:04 PM
Night The Perseid Meteor shower showcase charliezap Post Your Photos! 26 08-29-2015 12:36 AM
anyone capture the Perseids meteor shower? pete_pf Photographic Technique 26 08-14-2013 03:57 AM



All times are GMT -7. The time now is 09:40 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top