Here we will post soon lots of technical information concerning how to use a camera up to its limits, how to maintain it and how to repair it (repairing is one piece of information which lacks completely over the internet, and after thousands of hours uselessly spent seeking for it we think that's the best time to post everything we've learned in years concerning this subject)
So, in this section you'll find soon:
1. how to correct focus point on sigma 70-200/2.8 apo hsm
2. how to remove a nikon's d 70's mirror box- and pretty much everything else
in that camera- and, eventually, put back on 
3. more will come...