You either need a flash mounted directly to the hotshoe with the correct TTL capability or a Metz unit with the correct 3502 adapter mounted on the hotshoe. Note: one use a handle mount Metz unit for off camera flash but the 3502 must be on the hotshoe.
If you just want a signal and not TTL capability, set your SF20 on AUTO, set the ASA and f stop and use that way.
I use a Metz handle unit off camera with my 21mm without TTL because the 21mm finder must be on the hotshoe. Works fine.-Dick
Last edited by RichardB : 08-20-2010 at 04:13.