Hi,
I have converted some Leica R and Zeiss C/Y glass for Nikon through the Leitax route (
www.leitax.com). The Summicron 35mm is very sharp on a D3X in the center but it is very soft in the corners wide open untill f5.6. You have to crop the corners out as you can see it not even zoomed in, no problems on DX though it is just sharp. My Zeiss Sonnar 85mm f2.8 is a beauty, sharp and beautiful color. I show it here mounted on my D300.
Landscape and portrait with this lens on a D3X just stunning. I now even use my lenses on my Panasonic GH2 and with focus assist they are a joy to use.
My advice, instead of wide angle Leica R use the legacy Nikon Ais wide angles on a D3X they are great, I have the 28mm f2.8 Ais and you can't beat it. You can chip the Ais lenses for Exif info and aperture control from camera also from Leitax.
For standard and tele you can go the Leica and Zeiss route but you can't go wrong with original Nikon Ais glass either and it is less hassle.
Also have a look at
www.photozone.de and
www.slrlensreview.com for some reviews on Leica, Zeiss and Nikon glass. Also a great read for Canon users by the way.
Hope this helps.
Regards
Jaap
