field of view

The field of view in optics refers to the extent of the scene that a lens can capture. This is determined by the lens's angle of coverage, which is influenced by its focal length and design. A normal lens typically covers at least 60 degrees, while wide-angle lenses cover more, and long-focus lenses cover less.12

The aperture stop within an optical system limits the light beams passing through it. In photographic lenses, this is often an adjustable iris that controls illumination and depth of field. In telescopes and microscopes, the mount of a lens element can act as the limiting aperture. Vignetting occurs when these elements cut into oblique beams, reducing illumination in the outer parts of the field of view.3