Use the spanner wrench on
(slotted) of two rings on the front of the lens. Unscrew
counter-clockwise, this loosens the front optical block. Pull it out
and set aside somewhere safe.
Looking inside there is a lot going on, but thankfully it's more simple
than it looks.
Remove the screws the white
pointing too. Life out the spring and set aside with screws. Then
remove the screws the orange arrows are pointing to. Remove color
filters and set aside with screws. Finally remove the three screws the
blue arrows are pointing to. Now the rear optical block pulls out the
front and can be set aside.
The front optical block,
mechanism and spring mechanism.
It's interesting, the
built in hood is
attached to the rear optical block.
Remove the hard focus
stop that's held
in by two JIS screws.
I also removed the rear lens mount, but wouldn't suggest doing so at
this stage. This is what we're left working with, really just the
Now we're to the point of
no return. Slowly
unscrew the outer focusing helicoid. Go slow while pulling
the inner helicoid away from the outer body with constant
pressure. It's very
to know where the focusing helicoid separates, because it needs to be
threated back on in the same exact spot or focusing will be off when
reassembled. On my copy it was just over three turns.