the lens ring ( upper picture , loosen the two screws on each side of
the lens ring first ), move the Barrel in or out ( clockwise or
anti-clockwise ), focus to infinity using the ground glass . After
tighen lens ring & retighten two screws.
focus ring, if it's not in correct place
the front & rear elements of the lens out of the shutter, open all
tools to loosen the ring a bit
you can move theinfinitymark
retighen the ring ensure that it's tight. This action won't influence the focusing distance.