Some weeks ago I was able to test my new Samyang 35mm F/1.2 lens due to a more or less clear night. I attached the ASI178 mono camera to the lens using my E-mount to ASI adapter. Additionally I changed some parameters of my 'Astroschelle' dovetail lens adapter for the new lens dimensions. And it worked like a charm! The only thing that caused some headaches was how to fix the 36mm Halpha filter. First I tried to insert it into the ASI's T2 mount, but unfortunately there appeared severe reflections that led to asymmetrical halos around all stars! Finally I attached it in front of the lens using some chewing gum.
So, the question was: How does the lens perform fully opened? Short answer: It's a bit behind the extraordinary Samyang 135mm F/2.0 lens. A test shot with my Sony NEX in APS-C format revealed some issues like coma... towards the corners. The IMX178 used here crops the image by a factor of 3.0, so most of these issues are no longer visible. The resolution seems to be a bit lower than of the 135mm lens. I also experienced some halos in the image center, but that may actually come from the NB filter.
For a good comparison you can have a look at my previous Orion image, taken with the 135mm Samy at equivalent exposure conditions:
https://www.astrobin.com/327422/D/By the way, the darkframes did not match perfectly, so you will see some artifacts in the background...
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