[Leica] Is Zeiss 21/2.8 Biogon G retro-focal or symmetrical?

[Finney Tsai <tsai@syntest.com>]

Hi all,

Probably it is not adequate to ask questions regarding to
Zeiss optics in a Leica user group, but since it is somehow
related to Leica lenses, I think someone here may be able to
offer me his insight?
 
A few days ago, I chatted with a Leica expert.
He said that the new Leica 21/2.8 Elmarit-M Asph and
28/2.8 Elmarit-M Asph were both retro-focus design.
And he went even further to claim that
Zeiss 21/2.8 Biogon G (the one for the Contax G1/G2)
was also a retro-focus design. Now I am really confused.
I check out the lens diagram, the Zeiss 21/2.8 Biogon G
definitely looks very similar to the original 
Biogon design which is a well known symmetrical design,
as is the Super Angulon.

I know that in a broad term, Biogon can be considered
as a sort of reversed-telephoto design but here I am
talking about the typical retro-focus design
for those SLR wide angle lenses such as the 19/2.8 Elmarit-R.

Could anyone come out and explain these to me?

Thanks in advance.


- -finney