Shutter speed
Encyclopedia

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

, shutter speed is a common term used to discuss exposure time, the effective length of time a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

's shutter
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...

 is open.
The total exposure
Exposure (photography)
In photography, exposure is the total amount of light allowed to fall on the photographic medium during the process of taking a photograph. Exposure is measured in lux seconds, and can be computed from exposure value and scene luminance over a specified area.In photographic jargon, an exposure...

 is proportional to this exposure time, or duration of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 reaching the film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...

 or image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...

.

Introduction

In still cameras, the term shutter speed represents the time that the shutter remains open when taking a photograph. Along with the aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...

 of the lens (also called f-number
F-number
In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...

), it determines the amount of light that reaches the film or sensor. Conventionally, the exposure is measured in units of exposure value
Exposure value
In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

 (EV), sometimes called stops, representing a halving or doubling of the exposure.

Multiple combinations of shutter speed and aperture can give the same exposure: halving the shutter speed doubles the exposure (1 EV more), while doubling the aperture (halving the number) increases the exposure by a factor of 4 (2 EV). For this reason, standard apertures differ by √2, or about 1.4. Thus an exposure with a shutter speed of 1/250 s and f/8 is the same as with 1/500 s and f/5.6, or 1/125 s and f/11.

In addition to its effect on exposure, the shutter speed changes the way movement appears in the picture. Very short shutter speeds can be used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for artistic effect. Short exposure times are sometimes called "fast", and long exposure times "slow".

Adjustment to the aperture controls the depth of field
Depth of field
In optics, particularly as it relates to film and photography, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image...

, the distance range over which objects are acceptably sharp; such adjustments need to be compensated by changes in the shutter speed.

In early days of photography, available shutter speeds were not standardized, though a typical sequence might have been 1/10 s, 1/25 s, 1/50 s, 1/100 s, 1/200 s and 1/500 s. Following the adoption of a standardized way of representing aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...

 so that each major step exactly doubled or halved the amount of light entering the camera (2.8, 4, 5.6, 8, 11, 16, etc.), a standardized 2:1 scale was adopted for shutter speed so that opening one aperture stop and reducing the shutter speed by one step resulted in the identical exposure. The agreed standards for shutter speeds are:
With this scale, each increment roughly doubles the amount of light (longer time) or halves it (shorter time).

Camera shutters often include one or two other settings for making very long exposures:
  • B (for bulb
    Bulb (photography)
    Bulb, abbreviated B, is a shutter speed setting on an adjustable camera that allows for long exposure times under the direct control of the photographer. With this setting, the shutter simply stays open as long as the shutter release button remains depressed...

    ) keeps the shutter open as long as the shutter release is held.
  • T (for time) keeps the shutter open until the shutter release is pressed again.


The ability of the photographer to take images without noticeable blurring by camera movement is an important parameter in the choice of slowest possible shutter speed for a handheld camera. The rough guide used by most 35 mm
135 film
The term 135 was introduced by Kodak in 1934 as a designation for cartridge film wide, specifically for still photography. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film format...

 photographers is that the slowest shutter speed that can be used easily without much blur due to camera shake is the shutter speed numerically closest to the lens focal length. For example, for handheld use of a 35 mm camera with a 50 mm normal lens
Normal lens
In photography and cinematography a normal lens, also called a standard lens, is a lens that reproduces perspective that generally looks "natural" to a human observer under normal viewing conditions, as compared with lenses with longer or shorter focal lengths which produce an expanded or...

, the closest shutter speed is 1/60 s. This rule can be augmented with knowledge of the intended application for the photograph, an image intended for significant enlargement and closeup viewing would require faster shutter speeds to avoid obvious blur. Through practice and special techniques such as bracing the camera, arms, or body to minimize camera movement longer shutter speeds can be used without blur. If a shutter speed is too slow for hand holding, a camera support, usually a tripod
Tripod (photography)
In photography, a tripod is used to stabilize and elevate a camera, or to support flashes or other photographic equipment. All photographic tripods have three legs and a mounting head to couple with a camera...

, must be used. Image stabilization
Image stabilization
Image stabilization is a family of techniques used to reduce blurring associated with the motion of a camera during exposure. Specifically, it compensates for pan and tilt of a camera or other imaging device. It is used in image-stabilized binoculars, still and video cameras, and astronomical...

 can often permit the use of shutter speeds 3–4 stops slower (exposures 8–16 times longer).

Shutter priority refers to a shooting mode used in semi-automatic cameras. It allows the photographer to choose a shutter speed setting and allow the camera to decide the correct aperture. This is sometimes referred to as Shutter Speed Priority Auto Exposure
Shutter priority
Shutter priority refers to a setting on some cameras that allows the user to choose a specific shutter speed while the camera adjusts the aperture to ensure correct exposure...

, or Tv (time value) mode.

Creative utility in photography

Shutter speed is one of several methods used to control the amount of light recorded by the camera's digital sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...

 or film. It is also used to manipulate the visual effects of the final image beyond its luminosity.
Slower shutter speeds are often selected to suggest movement in a still photograph of a moving subject.

Excessively fast shutter speeds can cause a moving subject to appear unnaturally frozen. For instance, a running person may be caught with both feet in the air with all indication of movement lost in the frozen moment.

When a slower shutter speed is selected, a longer time passes from the moment the shutter opens till the moment it closes. More time is available for movement in the subject to be recorded by the camera.

A slightly slower shutter speed will allow the photographer to introduce an element of blur, either in the subject, where, in our example, the feet, which are the fastest moving element in the frame, might be blurred while the rest remains sharp; or if the camera is panned
Panning (camera)
In photography, panning refers to the horizontal movement or rotation of a still or video camera, or the scanning of a subject horizontally on video or a display device...

 to follow a moving subject, the background is blurred while the subject remains sharp.

The exact point at which the background or subject will start to blur depends on the rate at which the object is moving, the angle that the object is moving in relation to the camera, the distance it is from the camera and the focal length of the lens in relation to the size of the digital sensor or film.

When slower shutter speeds, in excess of about half a second, are used on running water, the photo will have a ghostly white appearance reminiscent of fog
Fog
Fog is a collection of water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated...

. This effect can be used in landscape photography
Landscape photography
Landscape photography is a genre intended to show different spaces within the world, sometimes vast and unending, but other times microscopic. This popular style of photography is practiced by professionals and amateurs alike. Photographs typically capture the presence of nature and are often free...

.

Zoom burst
Zoom burst
Zoom burst is a photographic technique, attainable with zoom lenses with a manual zoom ring.Using the technique involves zooming while the shutter is open with a relatively slow shutter speed, generally below 1/60th of a second. For this reason low light or small apertures are required...

 is a technique which entails the variation of the focal length of a zoom lens during a longer exposure. In the moment that the shutter is opened, the lens is zoomed in, changing the focal length during the exposure. The center of the image remains sharp, while the details away from the center form a radial blur, which causes a strong visual effect, forcing the eye into the center of the image.

The following list provides an overview of common photographic uses for standard shutter speeds.
  • 1/16000 s: The fastest speed available in APS-H or APS-C
    APS-C
    Advanced Photo System type-C is an image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives...

     format DSLR cameras (as of 2011). (Canon EOS 1D, Nikon
    Nikon
    , also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...

     D1
    Nikon D1
    The Nikon D1 is a digital single-lens reflex camera introduced on June 15, 1999. It featured a 2.7 megapixel image sensor, 4.5 frames per second continuous shooting, and accepted the full range of Nikon F-mount lenses...

    , D1X, and D1H)
  • 1/12000 s: The fastest speed available in any 35 mm film SLR
    SLR
    The initialism SLR can refer to:* Satellite laser ranging* Scalable Linear Recording Tape Drive Backup* Self-Loading Rifle, see semi-automatic rifle.** The UK version of the Belgian FN FAL select fire battle rifle, the L1A1 SLR.* Semi-linear resolution...

     camera. (Minolta
    Minolta
    Minolta Co., Ltd. was a Japanese worldwide manufacturer of cameras, camera accessories, photocopiers, fax machines, and laser printers. Minolta was founded in Osaka, Japan, in 1928 as . It is perhaps best known for making the first integrated autofocus 35mm SLR camera system...

     Maxxum 9xi
    Minolta 9xi
    The Minolta 9xi was, when new in 1992, an advanced 35mm Single-lens reflex camera design. It incorporated the world's fastest autofocus system , had a maximum shutter speed of 1/12000th of a second and a 14-zone metering system.The 9xi had been improved in many areas over the previous flagships,...

    ,
  • 1/8000 s: The fastest speed available in production SLR
    SLR
    The initialism SLR can refer to:* Satellite laser ranging* Scalable Linear Recording Tape Drive Backup* Self-Loading Rifle, see semi-automatic rifle.** The UK version of the Belgian FN FAL select fire battle rifle, the L1A1 SLR.* Semi-linear resolution...

     cameras (as of 2011), also the fastest speed available in any full-frame DSLR (as of 2011). Used to take sharp photographs of very fast subjects, such as birds or planes, under good lighting conditions, with a ISO speed of 1,000 or more and a large-aperture lens.
  • 1/4000 s: The fastest speed available in consumer
    Consumer
    Consumer is a broad label for any individuals or households that use goods generated within the economy. The concept of a consumer occurs in different contexts, so that the usage and significance of the term may vary.-Economics and marketing:...

     SLR cameras as of 2009. Used to take sharp photographs of fast subjects, such as athletes or vehicles, under good lighting conditions and with an ISO setting of up to 800.
  • 1/2000 s and 1/1000 s: Used to take sharp photographs of moderately fast subjects under normal lighting conditions.
  • 1/500 s and 1/250 s: Used to take sharp photographs of people in motion in everyday situations. 1/250 s is the fastest speed useful for panning
    Panning (camera)
    In photography, panning refers to the horizontal movement or rotation of a still or video camera, or the scanning of a subject horizontally on video or a display device...

    ; it also allows for a smaller aperture (up to f/11) in motion shots, and hence for a greater depth of field.

  • 1/125 s: This speed, and slower ones, are no longer useful for freezing motion. 1/125 s is used to obtain greater depth of field and overall sharpness in landscape photography
    Landscape photography
    Landscape photography is a genre intended to show different spaces within the world, sometimes vast and unending, but other times microscopic. This popular style of photography is practiced by professionals and amateurs alike. Photographs typically capture the presence of nature and are often free...

    , and is also often used for panning shots.
  • 1/60 s: Used for panning shots, for images taken under dim lighting conditions, and for available light portraits.
  • 1/30 s: Used for panning subjects moving slower than 30 miles per hour (13.4 m/s) and for available-light photography. Images taken at this and slower speeds normally require a tripod
    Tripod
    A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...

     or other camera support to be sharp.
  • 1/15 s and 1/8 s: This and slower speeds are useful for photographs other than panning shots where motion blur is employed for deliberate effect, or for taking sharp photographs of immobile subjects under bad lighting conditions with a tripod-supported camera.
  • 1/4 s, 1/2 s and 1 s: Also mainly used for motion blur effects and/or low-light photography, but only practical with a tripod-supported camera.
  • B (bulb)
    Bulb (photography)
    Bulb, abbreviated B, is a shutter speed setting on an adjustable camera that allows for long exposure times under the direct control of the photographer. With this setting, the shutter simply stays open as long as the shutter release button remains depressed...

     (1 minute to several hours): Used with a mechanically fixed camera in astrophotography
    Astrophotography
    Astrophotography is a specialized type of photography that entails recording images of astronomical objects and large areas of the night sky. The first photographs of an astronomical object were taken in the 1840s, but it was not until the late 19th century that advances in technology allowed for...

     and for certain special effects.

Cinematographic shutter formula

Motion picture cameras used in traditional film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...

 cinematography
Cinematography
Cinematography is the making of lighting and camera choices when recording photographic images for cinema. It is closely related to the art of still photography...

 employ a mechanical rotating shutter
Rotary disc shutter
A rotary disc shutter is a type of shutter. It is notably used in motion picture cameras.Rotary discs are semicircular mirrors which rotate in front of the film gate, and thus expose the film. As the mirror spins it reflects the image onto the ground glass so that it can be viewed by the camera...

. The shutter rotation is synchronized with film being pulled through the gate, hence shutter speed is a function of the frame rate
Frame rate
Frame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...

 and shutter angle.

Where E = shutter speed (reciprocal of exposure time in seconds), F = frames per second, and S = shutter angle:
, for E in reciprocal seconds



With traditional shutter angle of 180° film is exposed for 1/48 second at 24 frame/s. To avoid effect of light interference when shooting under artificial lights or when shooting television screens and computer monitors, 1/50 s (172.8°) or 1/60 s (144°) shutter is often used.

Electronic video cameras do not have mechanical shutters and allow setting shutter speed directly in time units. Professional video cameras often allow selecting shutter speed in terms of shutter angle instead of time units, especially those that are capable of overcranking or undercranking.

See also

  • exposure
    Exposure (photography)
    In photography, exposure is the total amount of light allowed to fall on the photographic medium during the process of taking a photograph. Exposure is measured in lux seconds, and can be computed from exposure value and scene luminance over a specified area.In photographic jargon, an exposure...

  • exposure value
    Exposure value
    In photography, exposure value denotes all combinations of a camera's shutter speed and relative aperture that give the same exposure. In an attempt to simplify choosing among combinations of equivalent camera settings, the concept was developed by the German shutter manufacturer in the 1950s...

  • f-number
    F-number
    In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...

  • shutter
    Shutter (photography)
    In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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