What is focus

focus, the

Examples:

A larger aperture number is more suitable for landscape shots, for portraits you choose a smaller number, i.e. a more open aperture - so the face is in focus, the background is blurred. [Fränkischer Tag, 14.08.2019]

One report states that some Spaniards have felt uglier since the lockdown and are therefore increasingly going to the cosmetic surgeon. A doctor describes the concerns patients come to her with: dark circles, sagging skin, large pores, wrinkles, and a nose that is too big. These newly discovered defects are related to the angle, focus, or quality of the camera. [St. Galler Tagblatt, June 8th, 2020]

The motif should be clearly distinguishable from the background, since the camera itself decides where the focus is in automatic mode. [Aachener Zeitung, July 20, 2019]

Through a complicated system of prisms, mirrors and lenses, light is thrown onto the gallery walls by several slide projectors, which, depending on the position of the glass focus or counterpart, appears to be directed, divided or fanned out in spectral colors. [Die tageszeitung, 16.01.1993]

Focal point, focus, in optics the point [...] at which light rays intersect after refraction by lenses or reflection from concave mirrors if they go parallel to the axis before refraction or reflection; A special point in geometry for conic sections. [Brockhaus ’Small Conversation Lexicon. Berlin: Directmedia Publ. 2001 [1906], p. 10484]