You don't say who the manufacturer of the lens is, so i assume it is a Samyang of which I know nothing about. However you can read all about it Here
. It generally gets quite good reviews. However the fact that there are reviews means that it should work. Saying it doesn't work does not give enough information for us to help. Be more specific as it could be a wrong camera setting or a bad lens and a number other reasons in between.
Sony A7, A850, A77, A700 || Sony>> 70-300G, 28-75 f2.8 SAM, 16-80CZ, 50 f1.4, FE 28-70 OSS, FE 24-70CZ f4 OSS, LA-EA4 || Minolta>> 300 f4 G HS, 200 f2.8 G HS, 100 f2.8 (D) Macro, 50 f1.7, 28 f2.8, 28-135 f4-4.5, 70-210 f4, 500 f8 Reflex, TC x 1.4 HS, TC x 2 HS. || Sigma 21-35 f3.5-4.2. || Tamron SP 24-135.