JAS adapter... Contax 645 lenses on Nikon or Canon with full dedication
I've been using a Contax 645 system (4 bodies with all lenses but the 350) and two digital backs (both with multishot ability) for the last 10 years, I'm also using Nikon for the last 32 years... My major problem was always how to restrict the equipment I have to carry... Problem solved 5 months ago.
The JAS adapter doesn't come cheap ($ 850), but it allows one to use all his C645 glass onto my Nikons with full dedication and really fast and accurate AF functioning...
Thus, I sold all my (first rate) Nikkor glass and only kept the 17-35mm/2.8 to have for wide angles, the 85mm micro PC to have for movements and the old 35-70/2.8 because it was cheap to sell and a nice, small walk around lens...
1. The crop factor makes all C645 lenses sharp to the corner at full aperture.
2. The near focus of the 140/2.8 is no more a problem because one has to add distance between the subject.
3. The IQ is clearly better in all focal lengths.
4. There is a half a stop gain in DR after processing, because the Zeiss glass has amazing flare resistance which increases mid contrast.
5. The 80mm/2 must be the best portrait lens that exists if used on a DSLR.
6. The 45/2.8 is sharp to the corners at full aperture due to the crop factor.
7. AF performance is at least 90% than if one is using a Nikkor AF-S lens (and clearly better than Nikkor AF-D)...
8. The 120mm f4 Apo micro blows the Nikkor 105mm micro VR away easily.
9. The mutar 1.4x teleconverter doesn't affect image quality
10. I have to only add a Nikon body alongside the C645 equipment I have to carry.... Sold 11 lenses!
-The 35/3.5, 55/3.5 and 45-90/4.5 Vario are slow and bulky (but of great optical performance)...