minimum working distance is 150mm; focus limiter; approx. 3100pcs produced
Carl Zeiss AF 400mm F4.0 Tele-Apotessar T*
*has a filter slot for insertable screw-in type filters, tripod collar; second last lens ever released in the line up; approx. 600pcs produced
Contax NAM-1 Conversions - Conurus C645 Adapter Beta Lite
The Contax NAM-1 was an adapter to mount Contax 645 lenses to Contax N cameras. Conurus offers a C/EF modification to mount it to Canon EOS cameras. It exclusively supports the original Contax 645 AF lenses. Using any other 645 lens (like Arsat 30mm Fisheye or Hartblei Superrotators) will result in camera failure showing "Err01" (there is a workaround by slightly unmounting the adapter by approx. 5°). The modification was/is offered as beta product only by high customer's demand.
First versions (2009) were not compatible with the AF of the Distagon 3.5/55 and the Tele-Apotessar 4/350 (resulting in focusing errors). In order to exchange the lens, the adapter needed to be unmounted from the body, before the lens could be unmounted from the adapter. By 2010 compatibility for the Distagon 3.5/55 and the Tele-Apotessar 4/350 was added. Also it was no longer necessary to unmount the adapter from the camera to exchange the lens. In 2011 support for Mutar 1.4x was added (requires factory firmware update).
Contax N system was introduced in 2000 and abandoned in 2005, with the 1.4/85 being the last lens going into production. The Contax trademark is still owned but actually not actively used by Zeiss.
Conurus is a weekend/free time driven company from Vancouver (Canada) founded in 2006. They do not sell the lenses, only the modification. You send in your lens and it might last a few months for the conversion to get completed. Until now this service is limited to costumers from countries supplied by Canadian Post Xpresspost-International Service.
Contax N lenses don't feature an AF/MF switch by default (at least some do feature Dual Focus though), but an aperture ring. Since the aperture is controlled by the body after the conversion, the aperture ring gets useless and thus remodeled to an AF/MF switch.
Conorus conversions are furthermore modified to micro-adjust the AF accuracy of the lens (again via the afterwards useless aperture ring). Read here, how it works.