I have an old Nikkor 55mm 3.5 AI with PK-13 extension tube. Was originally used on an F3-HP.
Recently I purchased a D7000, would like to use the lens, but as you know the "innards" of this lens are exposed to the camera body when inserted, ie, the threads, grease, etc...so of course I am concerned what may happen if I use this lens with the D7K and possible sensor contamination issues....does anyone here see this as an issue?
I use a MF55mm f2.8 Micro Nikkor on my D700 and D800 with excellent results and no problem with any contamination (I never had a contamination problem with any of my 30+ Ai and AiS lenses with any of my film Nikons).
"Great things are not done by impulse but by a series of small things brought together." Vincent Van Gogh