ePhotozine reviewed the Kamlan 50mm f/1.1 using the Sony a7RII in APS-C mode and it did pretty well for an inexpensive Chinese lens.
“Looking first at central sharpness, at f/1.1 the standard is only fair and the image is really quite soft. By f/2 the image sharpness is very good, and from f/2.8 right through to f/16 it is excellent.
At f/1.1 to f/2.8 edge sharpness is poor and the images are very soft. This starts to perk up by f/4, although the standard here is still only fairly sharp. At f/5.6 and f/8 things click in and sharpness is again excellent, tailing off slightly at f/16 but still being very good.
It needs to be borne in mind though that a test target is flat, and a simple f/1.1 lens is likely to have quite a bit of field curvature, so real-world images might be somewhat sharper all over.”
You can read the full review here. You can also check out some samples here and here.
The Kamlan 50mm f/1.1 can be purchased at Amazon