Some pictures of the focus element

Note the varnish / thread-lock on the screws inside the special white spacers. This is aligning the lenses.

The white spacers will be eccentric, so as they are rotated through 360 degrees (note the torx shaped inner wall), the lens will lift up or down, and then can be locked in place with the screw.

disassembling and reassembling this section will require marking each spacer exactly so that it can be put back in precisely the correct location.

Note the optical proximity sensor which is detecting the inner mechanisms endpoint (towards the motor).