A Definition of Focus
Kate Kiefer, English Department, Composition Director 1992 -1995
The focus of the text is also referred to as its thesis, theme, controlling idea, main point. In effect, writers tell readers what territory they plan to cover. That's the focus. A focus can be very narrow--as when a photographer takes a close-up of one mountain flower--or it can be broad --as when the photographer takes a long-range shot of the mountain. In practical writing, the focus is often specified for the writer by the "occasion" for the writing.
In their discussions of focus, writers may use a number of terms: main point, thesis, theme, position statement, and controlling idea. What these terms have in common—and what focus is really all about—is informally known as sticking to the point.
Sticking to the point involves having a clear idea of what you want to write and how you want to write about your topic. While you write, you'll want to keep in mind your supporting details to help your readers better understand your main point.
Coordinating all the aspects of your paper requires you to make each part work with the whole. Imagine your writing is a symphony orchestra in which one out of tune instrument will ruin the sound of the entire performance.