focus on someone or something
1. Lit. to aim and adjust a lens (including the lens in the eye) onto someone or something. I focused on the flower and pressed the shutter release. I focused on Fred and snapped just as he moved.
2. Fig. to dwell on the subject of someone or something. Let's focus on the question of the electric bill, if you don't mind. Let us focus on Fred and discuss his progress.
focus something on someone or something
1. Lit. to aim a lens at someone or something and adjust the lens for clarity. I focused the binoculars on the bird and stood there in awe at its beauty. He focused the camera on Jane and snapped the shutter.
2. Fig. to direct attention to someone or something. Could we please focus the discussion on the matter at hand for a few moments? Let's focus our attention on Tom and discuss his achievements so far.