bring something into focus
1. Lit. to make something seen through lenses sharply visible. I adjusted the binoculars until I brought the bird sharply into focus. The flowers were brought into focus by adjusting the controls.
2. Fig. to make something clear and understandable. I think we will have a better discussion of the problem if you will say a few words to bring it more sharply into focus. Please try to bring your major point into focus earlier in the essay.
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.
*in focus
1. Lit. [of an image] seen clearly and sharply. (*Typically: be ~; come [into] ~; get [into] ~; get something [into] ~.) I have the slide in focus and can see the bacteria clearly.
2. Lit. [for optics, such as lenses, or an optical device, such as a microscope] to be aligned to allow something to be seen clearly and sharply. I've adjusted the telescope; Mars is now in focus.
3. Fig. [of problems, solutions, appraisals of people or things] perceived or understood clearly. (*Typically: be ~; get [into] ~; get something [into] ~.) Now that things are in focus, I feel better about the world.
*out of focus
blurred or fuzzy; seen indistinctly. (*Typically: be ~; get ~; go ~.) What I saw through the binoculars was sort of out of focus. The scene was out of focus.