canon 50mm 1.8 SC
they are cheap on ebay, but are those lenses any good for video?

S.C. is a type of coating. I think you might be referring to FD lenses, a lot of which were marked with S.C.

FD lenses are not suitable for the EF/EF-S mount, because the adapters available require an optical element to achieve infinity focus. You will lose image quality this way, so it's just not worth it. If it was possible to adapt, FD lenses would be great for video.

There are plenty of other cheap 50mm lenses on ebay that will adapt well though.

thank for reply
I was looking on this

CANON FD 50MM 1.8 S.C. BREECH LOCK LENS, VERY NICE - eBay (item 290444372200 end time Jun-21-10 16:59:42 PDT) (http://cgi.ebay.com/CANON-FD-50MM-1-8-S-C-BREECH-LOCK-LENS-VERY-NICE-/290444372200?cmd=ViewItem&pt=Camera_Lenses&hash=item439fd568e8)