Recent thread about 4/300 inspired me to try this one. Meet the Carl Zeiss Jena Sonnar 4/300:
I adopted it to my Canon 5D using Fotodiox Kiev-66 -> Canon adapter ($30 at eBay). Here is my even more boring garage view:
I have nothig else in 300mm range to compare it with, so I took C/Y Sonnar 2.8/135 and put it on Mutar II extender. Yes, I know, this is not fair, but this is what I have. Below are results, center goes first:
CZJ @f4
Left - CZJ @f5.6, Right - C/Y @f2.8 (effective f5.6)
Left - CZJ @f8, Right - C/Y @f4 (effective f8)
Left - CZJ @f11, Right - C/Y @f5.6 (effective f11)
Left upper corner palm:
CZJ @f4
Left - CZJ @f5.6, Right - C/Y @f2.8 (effective f5.6)
Left - CZJ @f8, Right - C/Y @f4 (effective f8)
Left - CZJ @f11, Right - C/Y @f5.6 (effective f11)
Looks like MF glass is not that bad cå to 35mm. Shallower DOF is IMHO a plus too. Yas, it's damn heavy, but if you carry both 35mm and Contax 645, this might be a saving actually - it fits both worlds.

I adopted it to my Canon 5D using Fotodiox Kiev-66 -> Canon adapter ($30 at eBay). Here is my even more boring garage view:

I have nothig else in 300mm range to compare it with, so I took C/Y Sonnar 2.8/135 and put it on Mutar II extender. Yes, I know, this is not fair, but this is what I have. Below are results, center goes first:
CZJ @f4

Left - CZJ @f5.6, Right - C/Y @f2.8 (effective f5.6)


Left - CZJ @f8, Right - C/Y @f4 (effective f8)


Left - CZJ @f11, Right - C/Y @f5.6 (effective f11)


Left upper corner palm:
CZJ @f4

Left - CZJ @f5.6, Right - C/Y @f2.8 (effective f5.6)


Left - CZJ @f8, Right - C/Y @f4 (effective f8)


Left - CZJ @f11, Right - C/Y @f5.6 (effective f11)


Looks like MF glass is not that bad cå to 35mm. Shallower DOF is IMHO a plus too. Yas, it's damn heavy, but if you carry both 35mm and Contax 645, this might be a saving actually - it fits both worlds.