Brennpunkt.
Fokussierung
Zusammenführen eines auseinanderlaufenden Strahlenbündels in einen Punkt; z.B. beim Licht durch eine Sammellinse oder einen Sammelspiegel, bei elektr. geladenen Teilchen mit Hilfe elektr. oder magnet. Linsen (d. h. geeigneter Felder).
Brennpunkt.
In photography, the distance that a lens must be moved in order to focus a sharp image on the light-sensitive film at the back of the camera. The lens is moved away from the film to focus the image of closer objects. The focusing distance is often marked on a scale around the lens; however, some cameras now have an automatic focusing (autofocus) mechanism that uses an electric motor to move the lens.