With the SI2K, also RED ONE systems which have been fitted with the aftermarket IMS mount system, likely lens use will be proper PL-mount or BNCR cine lenses. However some use of Nikon stills lenses may occur.

Go here for a comment relating to the IMS - Nikon mount and some older Nikon lenses which may cause some problems.

http://www.dvinfo.net/forum/p-s-technik-digital-image-converters/480786-p-s-ims-nikon-professional-mount.html#post1541192