>>3862176>Is the Tamron 28-200 a good lensYes.
>Is the Samyang 18mm a good lensIt has some issues in the edge of the frame.
Take a look at the Tamron 20mm.
It's actually even cheaper than the Samyang lens. And the optical quality on the Tamron is better.
The ultimate lens in this category is the 1st party Sony lens though. It's just costs more.