I haven't tried this lens but it may well work. Ideally though you should be keeping it mated to a lens with a smaller rear element than 50mm, to match the 50mm rear of the anamorphic. Such large glass as F1.2 - i.e the Canon 50 and 85 L lenses, are HUGE! It certainly won't be sharp at F1.2. At F2.8 you should get outstanding performance but like I say I haven't tested the 50mm.
I have tried it on the Olympus OM 55mm F1.2 and it does play well stopped down to 2.8, whereas the Iscorama vignettes a bit.
tkealey reacted to Andrew Reid in Anamorphic sample footage shot with the SLR Magic Anamorphot - and which lenses does it work best with?