Many Nikon lenses can be converted to other mounts quite easily...I have converted my Nikon 35mm f1.4 Ai-S and 105mm f2.5 Ai-S to Sigma SA mount. Both are excellent lenses and they work even better with the really sharp Foveon X3 sensor behind them.
I have'nt converted my 55mm and 200mm Micro Nikkors because I can gain a macro magnification advantage by using them via Roxsen Nikon-M42 adapter plus an M42-SA adapter.
