The leica conversion is via a leica adapter from I_source-global_store. Their leica adapters come with a ledge on which the chip can be easily and accurately mounted. The chip comes from big_is where it is mounted on an M42 adapter from which it must be removed. Their chips have adjustable aperture and can be custom set by them to the desired focal length.
The Zeiss conversion is from a Pentax-Leica adapter for macro only (no glass and no infinity focus) but with a chip that is not adjustable. On the sony end of the adapter inside the flange is a flat ribbed surface. That surface is bored about to the edge of the ribs to the same diameter as the contax bayonet it must replace. The flange is then cut of the body just below the chip and fitted to the bayonet bus on the contax lens. Because the sony camera has protrusions that need to move inside the diameter of the blades while the lens is being mounted the new bayonet cannot be mounted with the indexing line for aperture adjustment at 12:00 as it is on the Contax. It can be rotated to about 10:30 o'clock and everything will work fine. Be sure you have the original bayonet fit correctly before drilling the holes. There are extra holes in the bus that can be confusing but only the correct holes will allow the screws to go all the way in.
The leica focused to infinity without adjustment as the adapter was correct out of the box. The contax lens needed some shimming. The contax can be controlled in thickness when slicing it off the original converter. There is lots of meat on the finished adapter to adjust.
The biggest advantage to doing the contax adapter this way is that the only things that need to be done on the contax lens is for the aperture adjustment levers be trimmed off and the bayonet removed. There is no need to open up the lens any further than taking off the bayonet.
Here's a picture of the converter before and after: http://www.pbase.com/masimo/image/122897748/large.jpg
The gallery below shows sample shots from a leica kyocera 35-70mm f4 zoom and a contax 28-85mm f3.3-f22 lens converted to sony mount. All exif data will say whatever the particular chipped adapters are set to. The actual titles of the pics indicate aperture and focal length.
Gallery is here: http://www.pbase.com/masimo/leica_co...verted_to_sony