I have one of the older Vivitar Series 1 2xTC's from the EOS film days.
It performs really well, 7 elements in 4 groups, full multicoating, and the 5 + 3 pin connections from lens to body.
They were not a bad TC in their day .. Made in Japan quality.
Does anyone know anything about how these would work in today's EOS DSLR world ?


