don't know about the vivitars, but i use a promaster 7500edf and it works wonderfully, about $200-250


http://www.promaster.com/products/products.asp?CatID=150&CatSM=&SubCatID=3&a mp;CatName=Electronic%20Flash&SubCatName=Digit al%20TTL%20&sm=sm2_1503&dir=&page=PROD &product=7500EDF