Originally posted by wkraus The Samyang 16mm is APS-C only (as you probably know) and therefore not really an UWA, so you are surely better off with the Laowa. What software do you use for stacking? I’m using Hugin and while there may be more elegant and less work-intensive solutions it takes care of the distortion too (which is not too bad to begin with, but definitely not near-zero).
I'm on APS-C as well (K-3 and K-3ii) so getting a true ultrawide on that format is harder, that 16 was a contender as it is substantally wider than than my 28mm and a whole lot better for night shots than the 17mm fisheye takumar. For stacking it really depends on what I am doing with the shots. If it is deep sky images I use Deep Sky Stacker or Astro Pixel Processor (APP), and mostly APP now as it is better. DSS is free while APP is a paid product. For sky scenes with something in the foreground where I won't be stitching images together (similar to your shot)I use Sequator as it has the ability to freeze the ground and freeze the sky and stack each independently. If you need to stitch then stack each stack where the foreground remains the same and stitch in another program. For things like the moon and monster setups where you don't get the entire moon in the frame with a single shot but still what to stack a bunch images and stitch all at once I use Hugin and the tools it comes with. I've had really good luck stacking things like the moon even with a lot of noise using Hugin. There I will do the alignment of all the shots in the GUI and then use the command line tools do the actual combining of aligned shots. I gave up on photoshop for stacking and stitching as tools like Sequator, Hugin, APP, and DSS do a much better job of things once one knows where to use each one. If I am just straight stitching a panorama I will also use MS Image Composite Editor (MS ICE) as it also does a great job with stitching things together so I will stitch in ICE and Hugin and pick the one that turned out the best.
Here is one of the total eclipse from 2019 where I stacked 106 shots in Hugin. There was no stitching as the moon easily fits in the field of view of my 300mm but each shot had a lot of noise as that was my first eclipse attempt and didn't know what I was doing. I really had to push each shot a lot.
This one is 237 stacked images in DSS taken with my 400mm
This one is 329 shots stitched and stacked with the Hugin tools. Each shot was at 2000mm and f/20
And finally
this is one similar to yours with 143 images stacked in Sequator. That is an exceptionally dark location so you can get a back lit image from the light from the milky way. I even got a fair amount of sky glow (the greens and purples in the sky) which I had never seen before.
When it comes to distortion it usually isn't a problem with a handful of shots and yes hugin does a very good job of handling it with a few shots with not much movement of stars but lots of programs will struggle with large movements of things across the frame unless there is very little distortion.