In the field of

photography Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed ...

, a manual focus

camera A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...

is one in which the user has to adjust the

focus Focus, or its plural form foci may refer to: Arts * Focus or Focus Festival, former name of the Adelaide Fringe arts festival in South Australia Film *''Focus'', a 1962 TV film starring James Whitmore * ''Focus'' (2001 film), a 2001 film based ...

of the

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

by hand. Before the advent of

autofocus An autofocus (or AF) optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system ...

, all cameras had manually adjusted focusing; thus, the term is a

retronym A retronym is a newer name for an existing thing that helps differentiate the original form/version from a more recent one. It is thus a word or phrase created to avoid confusion between older and newer types, whereas previously (before there were ...

. The focus itself may be adjusted in a variety of ways. Larger

view camera A view camera is a large-format camera in which the lens forms an inverted image on a ground-glass screen directly at the film plane. The image is viewed and then the glass screen is replaced with the film, and thus the film is exposed to exact ...

s and the like slide the lens closer or further from the

film plane A film plane is the surface of an image recording device such as a camera, upon which the lens creates the focused image. In cameras from different manufacturers, the film plane varies in distance from the lens. Thus each lens used has to be chos ...

on rails; on smaller cameras, a focus ring on the lens is often rotated to move the lens elements by means of a helical screw. Other systems include levers on the lens or on the camera body. There are a number of ways in which focus may be determined. Simplest is using a distance scale and measuring or estimating distance to the subject. Other methods include the

rangefinder A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography an ...

, which uses triangulation to determine the distance. On other cameras, the photographer examines the focus directly by means of a focusing screen. On the view camera, this ground glass is placed where the film will ultimately go, and is replaced by a sheet of film once focus is correct.

Twin lens reflex A twin-lens reflex camera (TLR) is a type of camera with two objective lenses of the same focal length. One of the lenses is the photographic objective or "taking lens" (the lens that takes the picture), while the other is used for the viewfind ...

cameras use two lenses that are mechanically linked, one for focusing and the other to take the photograph.

Single lens reflex A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With twin le ...

cameras, meanwhile, use the same objective lens for both purposes, with a mirror to direct the light to either the focusing screen or the film. Focusing screens, in their simplest form, consist of a matte glass or plastic surface on which the image can be focused. Other devices, such as split-image prisms or microprisms, can help determine focus. Manual focus lenses can also be used on modern digital cameras with an adapter. Zeiss, Leica and

Cosina Voigtländer Cosina Voigtländer refers to photographic products manufactured by Cosina under the Voigtländer name since 1999. Cosina leases rights to the Voigtländer name from RINGFOTO GmbH & Co. ALFO Marketing KG in Germany. Cosina Voigtländer products have ...

are among current manufacturers who continue to make manual lenses in lens mounts native to modern cameras.

References

{{Reflist Photographic techniques