Talk:Focus/@comment-70.52.36.169-20151229140448/@comment-38.100.188.54-20151229163938

You can put one lens on every single weapon and frame you have, if you want (and can get them). You can take up to 4 lenses into a match (frame, prim, second, melee) and they can be from any school and will all gain their own experience.

As for farming, high level endless matches or soloing high level stealth kills if you are good at that.