Maybe I was not accurate in my question, but English is not my first language, so I apologize for that.
But I wanna know tools helpful for the focus, so it's tools helpful for the focus puller more than the AC (In Belgium, it's the same title)
And for tilt shift lenses or split diopters, it's the same, it's tools that can play with the focus to give something more to it
Sorry to have expressed myself badly