Thursday, November 15, 2012

List of Abbreviations used in photography

Acronyms and initialisms that are not brand-specific
Automatic exposure. Hardware and software ("firmware"), built into the camera, measures luminance of the subject and automatically sets shutter speed, lens aperture or sensitivity.
Automatic exposure lock. Technology for holding an exposure setting from one scene to another.
Autofocus. The lens is focused automatically by means of the camera's hardware and firmware, to obtain optimum sharpness of an image.
Autofocus lock. Locks a particular focus setting, preventing refocusing if the scene changes.
Additive system of Photographic EXposure. A system to aid calculation of correct exposures, developed in the 1960s. Some aspects are included in Exif.
A film format defined by the Advanced Photo System as 25.1 × 16.7 mm. Different manufacturers use this term for image sensors measuring between about 20.7 × 13.8 mm to 28.7 × 19.1 mm.

The American Standards Association (now called the American National Standards Institute, ANSI) defined the ASA system for rating the speed sensitivity of photographic emulsions; now superseded by the ISO system.
Aperture value. Aperture priority automatic exposure mode, where the photographer sets the lens f-stop and the AE firmware sets the shutter speed.
Automatic white balance. A setting that allows the camera's hardware and firmware to estimate the colour temperature of the scene.
Chromatic aberration. Failure of a lens to focus all colours at the same point. The aberrations can be along the optical axis (Longitudinal CA, or LoCA) or off-axis (Lateral or Transverse CA, TCA).
Charge-coupled device. A semiconductor technology, used to create photosensor arrays for some digital cameras.
Catch-in-focus. A technique for allowing a camera to be pre-focussed to a defined spot, and the exposure is only made when a subject is in focus at that spot. Also called trap focus.
Complementary metal oxide semiconductor. A semiconductor technology, used to create photosensor arrays for some digital cameras.
CMYK color model. A subtractive process for colour printing that utilises cyan, magenta, yellow and black inks to create any printable colour. It is possible to omit black ink, in which case the process is termed CMY.
CP, CPL, or CPoL
Circular polarizing filter.
Compact System Camera. Mirrorless interchangeable-lens camera, smaller than a Digital single-lens reflex camera.
Design rule for Camera File system. A digital camera file system standard; JEITA number CP-3461.
Deutsches Institut für Normung. A logarithmic system for expressing film speed in common use in Europe since 1934. Now combined with the ASA linear system, in the form of the ISO system.
DOF or DoF
Depth of field. A measure of the permissible distance within which an object remains in acceptable, though not perfect, focus. Calculations of DOF assume that an imperfectly focused "circle of confusion" smaller than 0.20 to 0.25 mm is indistinguishable from perfect focus in an image viewed from a normal distance.. This is approximately equivalent to 0.03 mm in the case of an image on 35 mm film or FF format.
Dots per inch. A measure of the ability of a printer or scanner to handle fine detail.
Dynamic range. Expresses the luminance range of a scene, a captured image or the maximum range of luminance that a camera can successfully capture at one setting. It is often used imprecisely, but can sometimes be quantified as a ratio. The term contrast ratio may be preferred for the luminance range in a scene.
Digital single-lens reflex camera; also dSLR.
Extra Low Dispersion glass. Used in composite lenses to reduce chromatic aberration. One of a class of special glasses, including Anomalous Dispersion (AD), Special Low Dispersion (SLD) and Extraordinary Low Dispersion (ELD) glass, used in place of fluorite.
Electronic first curtain, electronic front curtain, electronic first curtain shutter, electronic first shutter curtain of a focal plane shutter.
Exposure value. A system for indicating correct exposure in which the shutter speed and f-number are related arithmetically.
Electronic viewfinder. The through-the-lens view is displayed on a miniature solid-state screen, rather than on an optical screen or view.
Electronic viewfinder interchangeable lens camera. See also MILC, Mirrorless interchangeable-lens camera.
Exchangeable image file format. A standard format for tag data in digital camera files.
f-number, f-stop. The numerical value of a lens aperture. The ratio of the focal length of the lens divided by its effective aperture diameter.
Full frame, where the image sensor is approximately the same size as a 35 mm film negative: 36 × 24 mm.
Focal plane. A shutter that opens and closes near to the film or image sensor, usually as a fast-moving slit, as contrasted with a bladed/leaf shutter located near a nodal point of a lens.
Focal plane array. A matrix of sensors positioned in the focal plane of a lens or other focusing device.
Frames per second. Used in reference to maximum continuous shooting rate or video.
Graphics Interchange Format. A computer file format for coloured images, restricted to 256 colours and useful for small file-size.
GNU Image Manipulation Program. Open-source software for editing digital images. Distributed free of charge.
Guide number. A value indicating the power of an electronic flash apparatus, and used to estimate exposure. GN = distance × f-number. One needs to specify the film or sensor ISO speed, and it is conventional to quote for ISO 100/21°. The distance can be in feet or in metres, the units to be specified.
Graduated neutral density. A type of neutral density filter in which brightness is reduced more on one side of the filter than on the other, allowing the photographer to reduce the contrast between, for example, bright sky and dark land.
High dynamic range. Techniques that allow a digital image to show a wider contrast range than current image sensors can record in one file. Some cameras have firmware to do the processing.
Image quality. An informal abbreviation used in discussion forums. Usually subjective, though some studies have analysed mathematically quantifiable components of image quality.
Infrared. The electromagnetic radiation with wavelengths longer than about 700 nm and not visible to the human eye.
Image stabilization. Technology to minimize image blurring by camera movement during exposure. See also AS, OS, OIS, OSS, SR, SS, SSI, SSS, VR as brand-specific terms.
A system for quantifying the sensitivity ("speed") of a photographic emulsion, or a solid-state digital-camera's image sensor, to visible light. Normally followed by a numerical value, e.g.: ISO 100 or ISO 64/19°. Developed from the ASA and the DIN systems by the International Organization for Standardization.
A format designed by the Joint Photographic Experts Group, that allows files of coloured images to be compressed to a smaller digital file than if the full range of colours were to be saved. Also .JPG as a computer file extension.
Lens Buying Addiction. Usually used in a jocular sense on camera forums, about a wish to add to an already extensive collection of interchangeable lenses.
An ambiguous abbreviation that should be avoided. Some writers use it to mean Lateral (transverse) chromatic aberration, TCA, while others use it to mean Longitudial (axial) chromatic aberration, LoCA.
Liquid crystal display. A technology often used in the monitor screens of digital cameras, etc.
Light-emitting diode. Semiconductor technology to convert electrical energy into light efficiently. Quasi-white and a range of colours, as well as infrared are possible.
Longitudinal (axial) chromatic aberration.
Lightroom, a popular software application for processing images from digital cameras. Developed by Adobe.
Multi-coating or multi-coated. Anti-reflection coating of lenses to reduce transmission losses. May also stand for meter coupling or meter-coupled lenses. Whilst being a generic term, the designation in the latter meaning is mostly used to describe a generation of Minolta SR-mount lenses implementing this feature.
Manual focus. The photographer adjusts the lens to obtain the image sharpness required, as opposed to AF. Alternative meaning: Medium Format. A size of film or image sensor somewhat larger than the 35mm film standard of 36 × 24 mm.
Mirrorless interchangeable-lens camera. Similar to a digital single-lens reflex camera, but having an electronic or rangefinder type of viewfinder in place of the mirror and pentaprism, to allow a more compact design. See also EVIL camera.
Modulation transfer function. A technical measure of the ability of a lens to create a finely detailed image. Several types of specialized apparatus are available to get the basic data on a lens and to analyse it. The calculated performance may be presented in various ways.
Neutral density. A neutral-grey pre-lens filter to reduce overall brightness without altering colour balance.
Noise reduction. Digital noise reduction through firmware processing or editing the digitized image.
OOF or OoF
Out of focus.
Optical viewfinder. The picture is framed on the focusing screen of a through-the-lens optical viewfinder, as found on [D]SLR cameras, or in a look-through-viewfinder, as found on rangefinder cameras.
Prontor-Compur or Pin Cylinder. A 3.5 mm coaxial camera jack named PC terminal, to synchronize external non-dedicated flashes (f.e. studio flashes), found on many more advanced camera models. Also may mean "Perspective Control" for a lens that has the ability to shift to tilt to control linear perspective in an image. May also stand for Personal Computer in conjunction with digital photography.
Purple fringing. A form of chromatic aberration in which a purple-violet haze degrades high contrast edges or over-saturated highlights. Some models of lens are widely criticised for this fault, though there are suggestions that it might also be due to properties of digital sensors.
Portable Network Graphics. A computer file format for compressed coloured images useful for small file-size.
Point-and-shoot camera. Photographers' slang for a small or compact camera that is easy to use because the essential functions are automated. Popular, but with limitations compared with more advanced cameras such as DSLR cameras with larger image sensors.
Photoshop, Photoshop Elements. Commercial computer applications developed by Adobe to facilitate the editing of digital images.
RGB color space. An additive colour space that uses the primary colours of red, green and blue to create any colour. There are several variants: sRGB, ISO RGB and some proprietary standards. Used mainly in colour displays: computer monitors, digital cameras, etc.
Resolving power. Usual meaning is the reciprocal of the distance between two just-distinguishable subject details.
Single lens reflex camera. A camera where the same lens is used to view the scene and to focus its image onto a film emulsion or solid-state photosensor. Usually combined with the facility to fit one of a range of lenses, and often more versatile than viewfinder/rangefinder cameras.
Sensitivity value. Sensitivity priority automatic exposure mode, where the photographer sets the ISO sensitivity and the AE firmware sets the aperture or shutter speed.
Transverse (lateral) chromatic aberration or Lateral colour. Colour fringes that worsen the further the image point is from the optical axis.
Tagged Image File Format. A high fidelity computer file format for handling digital images that does not sacrifice colour and form detail in the way that 'lossy' compression formats such as GIF, JPEG and PNG do.
Twin-lens reflex. A camera with two lenses, one for taking pictures and one for viewing the scene. The two lenses are typically linked to ensure that they remain focused at the same distance.
Through the lens. Through the lens metering measures the luminance after it has passed through the camera lens, thus providing readings or settings that allow for aperture and focus changes, filters, etc.
Time value. Shutter priority automatic exposure mode, where the photographer sets a shutter speed, and the AE firmware automatically sets the appropriate lens aperture.
Ultraviolet. The electromagnetic radiation with wavelengths shorter than about 400 nm and not visible to the human eye.

Initialisms that are used mainly by specific brands
Aperture priority mode (Nikon, Minolta, Konica Minolta, Sony, Olympus, Sigma brands), same as Av mode.
Advanced Distance Integration (Minolta, Konica Minolta, Sony brands). A technology to take distance information into account in combination with TTL flash metering.
AntiShake (Minolta, Konica Minolta brands). See IS in general usage.
Broad Band Anti Reflection (Tamron brand). Anti-reflection multi-coating of lenses to reduce transmission losses.
Digitally corrected (Konica Minolta, Sony, Sigma brands). A lens designation to indicate lenses which feature improved lens-coating but cover the APS-C image circle only. Also used for Defocus control (Nikon brand).
Digital Negative, an open raw image format promoted by Adobe and used by some camera manufacturers (f.e. Leica, Samsung, Ricoh and Pentax). Developed from the TIFF/EP digital image file format.
DX (Nikon brand). A designation for APS-C sized image sensors.
Electromagnetic Diaphragm (Canon brand). A more accurate and faster method of actuating a lens diaphragm.
FX (Nikon brand). A designation for full-frame sized image sensors. See FF for general usage.
Gold. A lens designation suffix applied to top grade Minolta AF and Sony Alpha lenses.
Hypersonic Motor. An autofocus motor (Sigma brand lenses).
Image Stabilizer (Canon brand). See general usage.
Luxury. A lens designation suffix applied to top grade Canon lenses, usually incorporating aspheric and low dispersion elements.
Optical Image Stabilization (Panasonic brand). See IS in general usage.
Optical Stabilizer (Sigma brand). See IS in general usage.
Optical SteadyShot (Sony brand). See IS in general usage.
Piezo Drive (Tamron brand). Autofocus mechanism that employs a piezo-electric motor.
Shutter priority mode (Nikon, Minolta, Konica Minolta, Sony, Olympus, Sigma brands), same as Tv mode.
Smooth Autofocus Motor (Sony brand). Autofocus mechanism that employs a piezo-electric motor or micro-motor.
Silent Drive Motor. An autofocus mechanism (Pentax brand).
Single-Lens Translucent (Sony brand). A variation of DSLR, but with fixed semi-transparent mirror.
Super Multi Coated (Pentax brand). Anti-reflection coating of lenses to reduce transmission losses.
Shake Reduction (Pentax brand). See IS in general usage.
SteadyShot (Sony brand). See IS in general usage.
SteadyShot INSIDE (Sony brand). See IS in general usage.
Super SteadyShot (Sony brand). See IS in general usage.
Supersonic-Wave Motor. An autofocus mechanism (Minolta, Konica Minolta, Sony brand lenses).
Smooth Trans Focus. A special purpose lens for pleasant Bokeh utilizing an apodization filter, or an autobracketing function to achieve the same effect (Minolta, Sony brand lens).
Silent Wave Motor. An autofocus mechanism (Nikon brand lenses).
T* (Carl Zeiss and Sony brands). Anti-reflection coating of lenses to reduce transmission losses.
Ultrasonic Silent Drive. An autofocus mechanism (Tamron brand lenses).
Ultrasonic Motor. An autofocus motor (Canon brand lenses).
Vibration Reduction (Nikon brand), see IS in general usage
Weather Resistant (mainly Pentax brand). Cameras and lenses with waterproof seals.

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