First remove five JIS
screws from the
rear lens mount, lift it out and set aside.
Remove two black JIS screws on aperture ring, lift off aperture ring
and set aside.
On the left you can see
the fork that
attached to the aperture ring by the screws we just took out, it
couples to the aperture by the small prong in the middle of the
picture. Pull it into the slot it slides in and ignore for now.
Here you can see I
removed the rubber
focusing grip hoping that it would come apart like the 105mm f/2.5. No
need to remove it on this lens. Instead, remove three slotted set
screws in the distance scale ring.
Pull the distance scale
ring back to
reveal three JIS screws on the focusing ring. Remove and set aside.
With the screws removed the focusing ring is loose. Extend the built in
hood and pull the focusing and distance scale rings down towards the
hood to reveal the infinity focus stop.
Before removing the infinity focus stop I deemed it prudent to scribe
it's location in case it moved once loose. You can see the dry focusing
helicoid and stripped center screw on the infinity stop. Now remove the
infinity focus stop.
Now we're to the point of
no return. Slowly
unscrew the inner focusing helicoid (the one with the big
that hits the infinity focus stop). Go slow while pulling
the inner helicoid away from the front 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