Manual Focus

In the field of photography, a manual focus camera is one in which the user has to adjust the focus of the lens by hand. Before the advent of autofocus, all cameras had manually adjusted focusing; thus, the term is a retronym.

The focus itself may be adjusted in a variety of ways. Larger view cameras and the like slide the lens closer or further from the film plane 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, 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 cameras use two lenses that are mechanically linked, one for focusing and the other to take the photograph. Single lens reflex 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.

Other articles related to "manual focus, focus, manual":

Tokina - History
... Another difference is the procedure for switching between manual focus and auto-focus ... With Tokina's "One-touch Focus Clutch Mechanism", you move the focus ring forward to enter auto-focus mode, and backward to enter manual-focus mode ... With Pentax's "Quick-Shift Focus System", introduced in early 2004 with the DA 16-45mm f/4.0, you just rotate the manual focus ring while staying in auto-focus mode ...
Carl Zeiss AG - Products - Camera Lenses - Z-series Manual-focus SLR Lenses
... Zeiss produces optically identical manual-focus lenses for multiple SLR lens mounts under the ZE, ZF, ZK, and ZS lines, manufactured in Japan by Cosina to ... feature electronic contacts allowing for focus-confirmation, and electric aperture operation as with standard Canon EF lenses ... They are manual-focus designs Nikon AI-S type aperture indexing ...
The Nikkormat F-series
... FT was an all-metal, mechanically (springs, gears, levers) controlled, manual focus SLR with match-needle exposure control, manufactured in Japan from 1965 to 1967 ... with the lens mount, unlike Nippon Kogaku's other manual focus SLRs with a top mounted shutter speed dial ... to freeze or blur motion and/or the lens aperture f-stop to control depth of field (focus) until the needle was centered between two pincer-like brackets ...
Pentax ME F - Features and Operation
... ME F body from the front) to the original Pentax K mount (introduced 1975) to pass focus control information between the camera and the lens ... Almost all other Pentax K mount bayonet lenses will function properly under manual focusing, with the AF system providing focus indication – Asahi Optical called this ... There were over thirty contemporary manual focus Asahi Optical made lenses of the SMC Pentax-M and SMC Pentax-A types ...

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