Fun little lens, surprisingly good for a $69USD Fixed Focus body cap. Well built too, it's basically a solid Aluminum body cap with a surprisingly complex 6/4 design lens screwed in the middle (vs the typical 2 or 3 element toy lens in body-cap type lenses) and it's also faster than the usual f8.
I continue to be impressed by the value for the money from these 7Artisan lenses. They're not the best glass out there, but they are VERY usable and just about ideal for a budget limited photographer, especially if paired with a body like the X-T1.
Note the vignetting is a mix of lens & post. It does vignette, but not that badly.