SirMontgomery wrote:
I understand the basics of astrophotography,how to get an exposure ect. I recently upgraded to one of the best cameras on the market for this, the pentax k1, and I want to push it to it's limits. These are just 30 second exposures (a touch too long) at ISO 1600 on an old 28mm SMC f2.8 film lens at f/3.5 to help with the extreme vignetting. I'll be buying a 24mm f/1.4 later this week as I do a lot of landscape photography. I also ordered a remote shutter so I caan start to use the astrotracer function.
Photos were taken around 11:30pm to 12PM on sunday at Gold Creek Pond, NF-9080, Snoqualmie Pass, WA 98068.
I need advice on the post processing methods and pointers on stacking/dark images/ect, it's all new to me. I've never stacked images, I was always a one shot and done photographer (probably stems from film).
In the google drive folder I added the raw DNG files, if you can show me the way these come out properly edited and how it was done I would be incredibly thankful, I played with both of these for about 90 minutes a piece with shoddy results even after reading some online guides.
https://drive.google.com/open?id=0B5asYiM2YoEQRVZneGdYQU1ZTG8I understand the basics of astrophotography,how to... (
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Your images look really nice. As for stacking, stars move across the sky, and the land objects do not. So this adds some difficulty to the problem. I use DSS and Nebulosity for stacking, but I avoid land objects in those stacks. But there is a stacking program that is free that seems to have the means to handle stars and land, and it is called Sequator:
https://sites.google.com/site/sequatorglobal/homeHaving clouds is another obstacle too. They move, and at a different speed than the stars, so there is no way to deal with this other than shorter exposures and to not stack. Thus, this results in using higher ISO levels to capture enough light.
Something else that is commonly done is to take separate images for the stars and for the land objects and then to cut out the sky in the land objects image and lay it over the sky image such that it looks like it came from one single image. This allows you to properly expose the land to get a lower noise result, which by the way causes the stars to leave very noticeable trails. And then to expose for the stars so that there are no noticeable trails, or if there are no clouds, to stack multiple star shots which tends to improve the signal to noise ratio and also to cause stars to take on more roundness. This method also allows you to focus separately for the land and separately for the stars which also helps.
As for stars, they have to be absolutely, perfectly focused. If off even the slightest bit, they don't look good. I use the focus magnifier and really work on getting a perfect focus. I start with a bright star and get close to focus and then as it gets close to focus, the dimmer stars come into view and I pick the dimmest star I can work with to focus now for it to be the brightest it can be. What you will find is that this spot is very, very critical and just touching the focus ring may change the focus. I also find manual lens focusing to be easier than more modern lenses with focus-by-wire focusing. For example, the Rokinon/Samyang lenses all have wonderfully smooth focus rings.
As for lenses, not all lenses are good candidates for star imaging. Stars are point sources of light and tend to exasperate any faults of the lens. Some show coma distortion which causes stars to stretch away from the center. Some show astigmatism which causes the corner stars to look like flying sea gulls, or having mustaches. Some have CA problems which cause sharp edges to have blue/purple fringes. All of these problems are hard to get rid of, but usually stopping down a bit makes things better. In looking at your images, I do see some astigmatism and CA problems, but your focus seems good.
Many people my something like the iOptron SkyTracker which rotates the camera to keep the stars from trailing. They are actually quite good at doing this. And of course, you would want to turn it off to do the land objects.
You are certainly off to a good start, and I'm sure future tries will be even better.
As for noise, the best program for this is DxO Optics Pro, Elite Version. Their Prime Noise removal is absolutely the best. It is very computational and takes some time to remove the noise, but it does so without doing the pixel blurring that most of the others make use of. Its only requirements are that you use the original RAW image, and you do it first.
Let us know what 24mm lens you intend to buy as not all of them do well with stars.
I am adding an image taken using a Rokinon 135mm f2 lens (stopped down a notch) showing desired round stars. This one was done with a mono Atik Infinity camera and is a stack of 17 images of 15 sec each and shows the globular cluster m53 in the center, and a fainter NGC5053 off to the right, another globular cluster, in an image that is a 3.8 x 2.8 degrees FOV. The night sky is certainly addicting!