@Lonnie
mount is T2 - you get T2 adapters for ALL cameras - price of my Canon adapter was $4.60 incl.ship. from China. T2 for NEX is $7.49, ...
For me T2-Canon is enough, because I have Canon adapters for m4/3, NEX, NX ..
With three little screws you can adjust "up" for your camera with a small allen wrench. Necessary only once.
@Jim
it's best if you use a tripod, focussing must be very accurate - no problem with NEX and others.
I have since > 20 years a Makinon 500mm/f=8, but with KonicaAR mount - usable with mirrorless cameras, but not with DSLRs (like my Canons). T2 mount you can use with ALL cameras. Even with 2x converter for €25-€40 - sure not best quality - and you get 1000mm.
Reading amazon.de there are few diappointed people (what do they await from a $100 lens?) but most are delighted, found reality better than bad rumors.
I think Samyang (my lens is "Walimex pro") is available as Rokinon, Opteka, Vivitar and so on.
I bought if from amazon.de for € 88.90 ... then each day it was more expensive, one week later € 161
500mm/6.3 - of course few depth of sharpness ... but with NEX7 NO PROBLEM