In optics, high-powered refers to a lens or system of lenses that provides a high degree of magnification or possesses a very short focal length. A high-powered objective gathers light from a very small field of view and spreads it over a larger area, requiring precise focus and often suffering from shallower depth of field and lower relative brightness.
Heard on the job
You'll need a high-powered objective to resolve the fine structure of that filament.