The Samyang AF 12mm f/2 X is their first AF lens to be released for X mount and it is based on their very popular Samyang 12mm f/2 design which was manual focus. Below is a summary of the above review by Christopher Frost:
The lens is quite compact and has a weather-sealing gasket
There is only one adjustment on the lens the focus ring
The lens suffers from focus breathing
AF is reasonably fast, accurate, silent
62mm filter thread
Very simple plastic hood that mounts well, but you cant reverse it for storage
Optically as good as the old 12mm, but they improved the coatings
“Brilliantly sharp” wide open at f/2, but it gets soft towards the edges with some chromatic aberration
Corners get better up to f/8 where they peak
The optics are an older design that is always razor-sharp in the center, but only ok in the corners
Moderate barrel distortion and vignetting with corrections turned off, but the camera will correct this fine
Focus as close as 20cm
Close-up image quality is pretty sharp
Flaring performance is decent which is an improvement over the original
Very little chroma smearing at night but there is a little color fringing up until f/8
If you want sun stars stop down to f/11 and they get impressive at f/16
Bokeh is quite smooth for an ultra-wide lens
Samyang has fixed the weaknesses of the old manual focus lens with the exception of chromatic aberration which can be fixed in post
Pretty much everyone should enjoy this lens and it is at great price point