All the lenses are for the observer Staff. For sure. That is not an
issue. I have seen people complete this quest in akanon so it can be done.
There is a whole guild on the Povar server Named the Harmonium that have
these staffs from accomplishing the four lenses quest. granted You can
also get the staff off the borxx evil eye by obtaining his lense. But I
have seen high level characters in the mino caves in steam font get the lense
from the slave in there. They do it regularly to keep their lower level
guildies equipped.