page_title: Wide-angle lens
section_title: Construction
hierarchical_section_title: Wide-angle lens / Construction
context_page_description: In photography and cinematography, a wide-angle lens refers to a lens whose focal length is substantially smaller than the focal length of a normal lens for a given film plane. This type of lens allows more of the scene to be included in the photograph, which is useful in architectural, interior and landscape photography where the photographer may not be able to move farther from the scene to photograph it.
  Another use is where the photographer wishes to emphasise the difference in size or distance between objects in the foreground and the background; nearby objects appear very large and objects at a moderate distance appear small and far away.
  This exaggeration of relative size can be used to make foreground objects more prominent and striking, while capturing expansive backgrounds.
  A wide angle lens is also one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length. This large image circle enables either large tilt & shift movements with a view camera, or a wide field of view.
context_section_description: There are two varieties of wide-angle lens: short-focus lenses and retrofocus lenses.
  Short-focus lenses are generally made up of multiple glass elements whose shapes are more or less symmetrical in front of and behind the diaphragm. As the focal length decreases, the distance of the rear element of the lens from the film plane or digital sensor also decreases.
  This makes short-focus wide-angle lenses undesirable for single-lens reflex cameras unless they are used with the reflex mirrors locked up. On large format view cameras and rangefinder cameras, short-focus lenses are widely used because they give less distortion than the retrofocus design and there is no need for a long back focal distance.
  The retrofocus lens solves this proximity problem through an asymmetrical design that allows the rear element to be farther away from the film plane than its effective focal length would suggest. (See Angénieux retrofocus.)
  For example, it is not uncommon for the rear element of a retrofocus lens of 18 mm to be more than 25 mm from the film plane. This makes it possible to design wide-angle lenses for single-lens reflex cameras.
  The axial adjustment range for focusing Ultra wide angle lenses and some Wide-angle lenses in large format cameras is usually very small.
  Some manufacturers (e.g. Linhof) have offered special focusing lens mounts, so-called 'wide-angle focusing devices' for their cameras that allow the lens to be focused precisely without moving the entire front standard.
caption: Cross-section of a typical short-focus wide-angle lens.