Regarding the “New High Quality” image sample filtering vs “Old Tent”, which one is the new one in the “Type” dropdown under Image filter?
I see Symmetric Tent, Parabolic, Hann, and Blackman-Harris
Oh wait I see the checkbox now facepalm
For the future generations 
check out this guide: https://coronarenderer.freshdesk.com/support/solutions/articles/12000056115