The Medical Nikkor 120mm f:4 IF lens canbe used with the D-70 but in complete manual mode.

To operate the internal flash in the medical lens, you have to use the 3-pin Syn Cord SC-22, Attach one end of it into the lens and then slip the other end into the camera's hot shoe until it stops, and tighten the attachment screw. Set the flash control in the D-70 to complete manual mode. Then it will work.

If any query ask me on this same Thread.