[davidmanze]

I've seen lots of posts about infinity focus on Samyang lenses being poorly calibrated, here's a Utube video showing how to adjust the focus ring,  well I didn't in fact watch it, however it shows how th roll back the rubber to access the screws so you can adjust the it, I guess you use live view to focus on infinity and then undo the screws to set the ring.

  Unfortunately, it's in Spanish and is subtitled in French but you'll get the picture if you pardon the pun! It's of the Samyang 14mm but the principle's the same I think!

 

https://www.youtube.com/watch?v=gtt9bcJD...e=youtu.be

 

 

 My 8mm fish eye was OK!