Thanks Ivar.
All these old Zeiss lenses for the Contax/Yaschica (CY) SLR are manual. I bought them some time ago from a friend of my father in law. He didn't used them anymore and offered them to me. I could not resist.
So I got a 18/4, two 28/2.8 , the 35/2.8, a 50/1.4, 60/2.8 Macro, two 85/2.8, a 100/4 Macro Planar to be used with bellows only, a 135/2.8 and a 180/2.8. I added the 35/2.8PC shift lens later on. Initially I had a Pentax K5 with newer Voigtländer lenses, but the Zeiss lenses fitted only using an adapter with additional lens to allow focusing to infinite. The performance of the Zeiss/Pentax combination with that adapter was not that good.
Therefore I switched to a used Canon 5DII. The flange focal length of the Canon EF mount is 44.0 mm, the Zeiss lenses with the CY-mount requiring 45.5 mm, allowing the mounting with a "lensless" adapter.
Some lenses extended into the mirror box of the Canon, the mirror striked against some lenses, especially the 18mm/4 and the 35/2.8 at infinite focusing. Of course I had to make some "modification" in the mirror box of the Canon (giving f.e the aperture lever some room), it worked. Focusing was manual (of course) but without any assistance. There are adapters available with focus confirmation, but I didn't used them. It worked and made fun.I'm still using it.
But when the Sony A7 came out, with its short flange focal length, all this hassle was gone. Focusing is assisted by 5x or even 10x magnification in the viewfinder. I do not use the focus peaking of the A7. It is not a fast system with these lenses, but it is what I currently like. The lenses are all fine, have all their own character and also their limitations.
I used the 28/2.8 quite a lot, it is a little more compact as the 35/2.8. I enjoy the 35/2.8 shift lens. It is huge, but it is fun to use it.
I'm noot sure, if I would better go today with the new lenses for the Sony A7. They are typically smaller, lighter, probably a better corrected. But again, these old lenses are still working good and make fun.