Photography Abbreviations and What They Mean

Nov 03, 2021

The world of photography is filled with abbreviations that allow longer words or phrases to be more easily communicated. If you’re just starting out as a photographer, however, they could be more confusing than helpful, and this guide was put together just for you.

Here’s a list of common abbreviations, acronyms, and symbols you’ll often hear when talking about photography and/or camera equipment:

A

A. Aperture priority. Also abbreviated on some mode dials as Av, for aperture value, this is a camera setting in which the photographer chooses a fixed aperture value (or f-number) while allowing the camera to adjust the shutter speed (and possibly ISO) to achieve a proper exposure (as determined by the camera’s internal light meter).

ACR. Adobe Camera Raw. An Adobe Photoshop plug-in that lets you import, process, and enhance raw photographs without going through Adobe Lightroom.

AE. Automatic exposure. Also known as autoexposure, this is a camera mode that automatically determines the optimal exposure settings, usually based on readings from a built-in exposure meter.

AE-L. Automatic exposure lock. A camera feature that allows the photographer to lock the current exposure settings. Often used in conjunction with AF-L, which locks autofocus. Can be used to recompose without re-metering.

AF. Autofocus. A system that allows a camera to focus a lens automatically to achieve optimal sharpness on an automatically-selected or manually-selected point or area.

AF-L. Autofocus lock. A camera feature that allows the photographer to lock the current focus. Often used in conjunction with AE-L, which locks exposure settings. Can be used to recompose without refocusing.

AoV. Angle of view. The angular extent of a scene that can be captured by a camera. This term is often used interchangeably with “field of view.” See FOV.

APEX. Additive System of Photographic Exposure. A system for simple exposure computation first proposed in the 1960 ASA standard regarding monochrome film speed. While APEX failed to become a fundamental standard in the camera industry, its use of Av and Tv to refer to aperture and shutter speed live on in modern cameras.

APS-C. Advanced Photo System type-C. The image sensor format based on the C (“Classic”) film negative size by the Advanced Photo System. These sensors have a range of measurements (usually 22.5x15mm to 24x16mm), have an aspect ratio of 3:2, and have a crop (usually 1.5x to 1.6x) compared to 35mm full frame. Thus, these cameras are often called “crop sensor” or “crop frame.”

ASA. American Standards Association. The standards body that defined the ASA system for rating the speed sensitivity of photographic emulsions. The private non-profit organization has since been renamed to American National Standards Institute (ANSI). In 1974, ASA and DIN were combined into the ISO standards used by photographers today.

ASPH. Aspheric. A lens element that uses a more complex surface profile that is not a portion of a sphere or cylinder in order to reduce various types of aberrations that simple lenses suffer from. A single aspheric lens element is able to replace multiple simple lens elements. Camera lenses that feature an aspheric element are often referred to as aspherical lenses.

AWB. Auto White Balance. A camera or software feature that evaluates a photo and automatically selects the optimal white balance with the goal of removing color casts from the scene.

B

B. Bulb. A camera shutter setting that keeps the shutters open for as long as the shutter-release button is being held down. The name refers to the rubber bulbs used as pneumatic shutter releases in early cameras — squeezing the bulb would open the shutter and releasing the pressure would close the shutter, so photos were exposed for as long as the bulb was being squeezed.

BBF. Back button focus. A camera feature that allows a separate button on the back of the camera to be used for focusing rather than pressing the shutter button halfway down.

B&W. Black and white. Also called monochrome, this type of photography features photos that only contain shades of neutral gray (or a hue such as sepia) that range from black to white, rather than color.

C

C1. Capture One. The photography software made by the Danish photography equipment and software company Phase One. The app offers raw file processing, photo cataloging, and tethered shooting.

CA. Chromatic aberration. Also called “color fringing,” this is a color distortion that occurs when a lens fails to focus all colors to the same point. It appears as an outline or fridge of color in areas of an image where there is high contrast between light and dark objects.

CC. Constructive criticism. Used by photographers requesting others to provide beneficial critiques of their work online.

CCD. Charge-coupled device. One of the two major types of semiconductor image sensors, with the other being CMOS. Advantages typically include a global shutter (all pixels are exposed at the same time), high resolution/sensitivity (due to pixels not having to share space with the amplifiers), and high-quality/low-noise. Disadvantages include high power consumption and high cost (a special manufacturing process is needed).

CDAF. Contrast-detection autofocus. An autofocus system that achieves focus by measuring contrast using a sensor through the lens. The camera attempts to focus on an object by adjusting the lens’ focus until maximum contrast at the focus point is detected. Compared to phase-detection autofocus, contrast-detection autofocus has poorer performance when it comes to tracking moving subjects.

CF. CompactFlash. A memory card format that is commonly used by digital cameras. Developed by SanDisk in 1994, it uses flash memory technology to store large amounts of data on relatively small devices. Its primary competitor is the Secure Digital (SD) card.

CIF. Catch in focus. Also known as “trap focus,” this is a method of photographing in which the photographer pre-focuses a camera to a particular spot and then the camera automatically triggers an exposure when it detects that a subject has walked into focus at that spot.

CMOS. Complementary metal–oxide–semiconductor. The dominant type of image sensor found in modern digital cameras (the other being CCD). Advantages include readout speed, low power consumption, and low cost (it uses traditional chipmaking processes). Disadvantages include rolling shutter (pixels are exposed line by line) and lower sensitivity (each pixel site shares space with an amplifier).

CMYK. Cyan, magenta, yellow, and black. A subtractive color model used in color printing that uses cyan, magenta, yellow, and key (black) ink plates on a light (usually white) background. As a subtractive model, the added colors are subtracted from white, and the full combination of colors is black. Color printers are generally CMYK.

CP. Circular polarizing filter. Also abbreviated as CPL, a circular polarizer is a type of filter that attaches to a lens and cuts down on glare and reflections. A photographer can rotate the front part of the filter to control the polarization effect.

CSC. Compact system camera. Another name for mirrorless cameras. See MILC.

CWB. Custom white balance. A camera setting that allows photographers to set their own white balance, usually for situations with tricky or mixed lighting. This involves photographing something pure white or neutral gray in the same lighting to serve as a reference for the camera to adjust color temperature.

D

DAM. Digital asset management. Software that aids in the organization of large numbers of files. Features generally include importing, viewing, organizing, tagging, editing, and sharing. Popular apps include Adobe Lightroom and Adobe Bridge.

DDSSM. Direct Drive Super Sonic Wave Motor. Sony’s name for its ultrasonic motor lens technology in a linear motor. See USM.

DIN. Deutsches Institut für Normung. A logarithmic system for rating film speed that was introduced in 1934 before becoming widely used in Europe. In 1974, DIN and ASA were combined into the ISO standards used by photographers today.

DoF. Depth of Field. The distance between the nearest and farthest objects in a photo that are in focus by being acceptably sharp. A shallow depth of field can result in considerable blurring in front of and behind the subject that is focused on, while a wide/deep depth of field can render more (or all) of a scene in sharp focus.

DNG. Digital Negative. A lossless raw image format developed and patented by Adobe for use in digital photography. As an open format with freely available specs, DNG is designed to be a universal raw file format as an alternative to the proprietary raw formats developed by camera manufacturers.

DPI. Dots per inch. A way to measure the fine detail capability of a printer or scanner. Refers to the number of separate dots that can be put into the space of one linear (not square) inch.

DSLM. Digital single-lens mirrorless. Another name for mirrorless cameras. See MILC.

DSLR. Digital single-lens reflex. A digital camera that uses a mirror to direct light between the viewfinder prism (for seeing and composing the scene) and the image sensor (when the shutter is activated to expose a photo).

DR. Dynamic range. The range of light intensities, or luminance, between the maximum and minimum in a scene, from the highlights to the shadows. This is often used to refer to the limits of this range that a film or digital sensor can capture.

DSC. Digital Still Camera. Often used by various digital cameras as the prefix on the file names of captured digital photographs.

DX. Nikon’s name for its APS-C crop image sensor format, which measures approximately 24x16mm.

E

EC. Exposure compensation. A camera feature that allows photographers to over- or under-expose a photograph (often in 1/3rd stop intervals) relative to the proper exposure calculated by the built-in exposure meter.

ED. Extra low dispersion glass. Glass with extra-low dispersion that is used as elements in camera lenses to reduce chromatic aberration.

EF. Electro-Focus. Canon’s standard lens mount introduced in 1987 for its EOS family of film and digital SLR cameras. EF lenses autofocus using an electric motor inside each lens.

EF-S. Electro-Focus Small/Short. Canon’s lens mount introduced in 2003 and designed for EOS family DSLRs with APS-C sized sensors. EF lenses designed for full-frame cameras can be used on EF-S mount cameras, but EF-S lenses cannot be mounted on EF mount cameras. The ‘S’ in the name may stand for Small (referring to the smaller image circle) or Short (referring to the shorter distance between the lens and sensor).

EOS. Electro-Optical System. Canon’s family of autofocus cameras that was introduced in 1987. Originally launched for 35mm film SLRs, EOS has grown to include DSLR cameras as well as mirrorless cameras (with the introduction of the EOS-M line). The EOS line was also named after the Greek goddess of dawn.

EOS M. Electro-Optical System Mobility. Canon’s first family of mirrorless interchangeable-lens cameras.

ETTL. Evaluative though-the-lens. Automatic flash metering that fires a pre-flash, measures the resulting light that comes into the camera, and then uses that information to calculate the proper flash exposure time.

ETTR. Expose to the right. The technique of aiming to have as high an exposure as possible to collect as much light and information as possible without clipping on the histogram and losing detail by overexposing.

EV. Exposure value. A number representing the quantity of light hitting a camera’s film or sensor, as determined by the aperture and shutter speed. Different combinations of aperture and shutter speed that produce the same exposure have the same EV number.

EVF. Electronic viewfinder. A camera viewfinder in which the scene as seen through the lens is projected for the photographer to view with one eye on a miniature digital display.

EVIL. Electronic viewfinder, interchangeable lens. Another name for mirrorless cameras. See MILC.

EXIF. Exchangeable Image File Format. Officially stylized as Exif (without all caps), this is the standardized data that’s saved to every image file a camera records. Information contained may include date/time, camera/lens info, exposure details, GPS, and more.

F

f. f-number of f-stop. This is the number that specifies a lens’ aperture. It is the ratio of focal length to effective aperture diameter. A low f-number denotes a larger aperture size that allows more light to reach the camera’s film or sensor. One f-stop refers to a change of √2 (~1.41) in f-number and a factor of 2 change in light intensity.

FF. Full frame. The sensor size in digital photography based on the 35mm format that became dominant in film photography. A full frame sensor measures 36×24mm, an aspect ratio of 3:2, and a diagonal measurement of roughly 43mm.

FOV. Field of view. The portion of the world that is visible through and capturable by a camera. When expressed as an angle (of the view cone), this is also referred to as the angle of view (AOV). Field of view depends on the focal length of the lens and the size of the sensor/film.

FPS. Focal-plane shutter. A type of shutter that sits right in front of a camera’s focal plane.

FPS. Frames per second. This is a camera’s maximum continuous shooting (burst) rate for still photos or available frame rates for video.

FX. Nikon’s name for its full frame sensor format, which has dimensions based on that of 35mm film.

G

GAS. Gear acquisition syndrome. Often used to describe a photographer’s addition to continually purchasing new camera equipment, often without any real practical need.

GB. Gigabyte. A multiple of the byte unit for digital information storage. Since giga denotes 10⁹, a gigabyte is one billion bytes of data.

GIF. Graphics Interchange Format. A bitmap image format introduced in 1987 that supports 8 bits per pixel, meaning each image can display a maximum of 256 different colors. GIFs are ubiquitous on the Web due to the format being widely supported, but the color limitations make the format less suitable for photos than formats such as JPEG. However, photos are widely shared in GIFs in the form of online memes.

GN. Guide number. A number used to indicate the power of an electronic flash and used to calculate the necessary f-stop for any flash-to-subject distance (or the distance for a given f-stop). Guide number = f-number x distance. The larger the guide number, the greater the distance the flash can properly expose a subject.

GND. Graduated neutral density. A kind of neutral density filter in which the amount of light blocked is a gradient from one side to the other. Useful for scenes like landscapes where photographers need to reduce the contrast between a bright sky and a dark landscape.

GP. Gigapixel. One billion pixels. A term used to refer to the resolution of a photos, displays, and camera sensors.

H

HDR. High dynamic range. A type of photography that aims to reproduce a greater range of luminosity than what is ordinarily captured with standard photographic equipment and techniques. This is often done by capturing multiple photographs at different exposures and then combining them into one photo with a higher maximum and lower minimum tonal value.

HFD. Hyperfocal distance. A focus distance beyond which all objects in a scene are rendered with “acceptable” focus, resulting in the maximum depth of field at a given aperture.

HSM. Hyper Sonic Motor. Sigma’s name for its ultrasonic motor lens technology. See USM.

HSS. High-speed sync. A flash feature that allows you to synchronize your flash output when using shutter speeds faster than the camera’s native flash sync speed. Useful for scenarios such as adding fill-flash to a model outdoors on a bright day.

I

IBIS. In-body image stabilization. A mechanism found in digital cameras that compensates for camera movement while an exposure is being made by moving the image sensor at the final point of the optical path. These systems compensate for up to 5 axes of movement: X, Y, Roll, Yaw, and Pitch. While optical image stabilization (OIS) is built into individual lenses, IBIS in a camera works with all lenses that can be mounted to it.

ICM. Intentional camera movement. A type of photography in which the camera is moved or lens adjusted during an exposure for creative effect. These acts produce blurring in resulting photos, whether from the movement of the camera or from adjusting the focus or zoom of the lens.

IF. Internal focus. A design for camera lenses in which focus is achieved by only moving internal lens elements without any rotation or shifting of the front lens element. Advantages include the ability to more easily use certain filters (screwed-in polarizing) and hoods (petal), keeping dust out, not hitting macro subjects, avoiding “zoom creep,” and smaller lens designs.

ILC. Interchangeable lens camera. A camera that accepts interchangeable lenses rather than having a fixed non-removable lens.

IPS. In-person sales. A business model in which a photographer meets clients in-person to sell products or services. Rather than decide on final prices and packages prior to a shoot, an IPS photographer generally performs a photo shoot first and then meets with the client afterward to review the photos and sell them as various products and bundles.

IPTC. International Press Telecommunications Council. A London-based consortium of over 50 major news companies and organizations from around the world. As the global standards body of news media, the IPTC defined a standard for photo metadata that is the world’s most widely accepted and used.

IQ. Image quality. The quality of photos, often with regards to the performance and features of cameras (e.g. resolution, noise, dynamic range, color), lenses (e.g. sharpness, aberration, vignetting, distortion), and post-processing software.

IR. Infrared. Light of wavelengths typically between 700nm to 900nm that can be captured using film or image sensors sensitive to that part of the spectrum. Infrared photographs captured with visible light blocked typically have a dreamlike look featuring white foliage, dark skies, bright skin, and dark eyes.

IS. Image stabilization. A feature that compensates for camera motion during image exposure in order to reduce blur, particularly at slower shutter speeds. This can be both mechanical and electronic, and it can be found in both lenses and cameras.

ISO. International Organization for Standardization. A standard for measuring a camera film or sensor’s sensitivity to light. For film, this refers to how quickly the chemicals react to light, and for digital sensors, this refers to the gain (or amplification) applied to the signal before the image is recorded.

J

JPEG. Joint Photographic Experts Group. Also abbreviated JPG, this is a lossy compression standard named after the group that created it in 1992. It has since become the most widely used compression method in the world for digital photos. The fact that it’s lossy means that editing and resaving the files causes a loss in image quality each time.

K

K. Kelvin. The international base unit of absolute temperature that’s used to conveniently express color temperature in photography. Higher temperatures (e.g. over 5000 K) are cooler, bluer colors, while lower temperatures (e.g. under 3000 K) are warmer, yellower colors. “Daylight” is traditionally around 5600 K.

KB. Kilobyte. A multiple of the byte unit for digital information storage. Since kilo denotes 10³, a kilobyte is one thousand bytes of data.

L

LCD. Liquid crystal display. The display technology that’s ubiquitous in camera screens, viewfinders, computer monitors, and more. It uses liquid crystals, polarizers, and backlighting to produce the displayed images.

LED. Light-emitting diode. A semiconductor light source technology that has applications in photography ranging from lighting to displays. As a light source, they are flexible (with a wide range of colors and intensities), energy-efficient, low heat, and long-lasting. In a display, they are bright, energy-efficient, sharp, flicker-free, and long-lasting.

LR. Lightroom. Adobe’s Creative Cloud software for image editing and organization. Popular among photographers for managing files, culling large sets of photos, and their post-processing workflow.

M

M. Manual. A camera mode in which the photographer chooses the desired exposure by manually selecting shutter speed and aperture (and optionally ISO).

MB. Megabyte. A multiple of the byte unit for digital information storage. Since mega denotes 10⁶, a megabyte is one million bytes of data.

MF. Manual focus. A process in which a photographer (rather than the camera) adjusts the lens’ focus to achieve the desired sharpness in a photo.

MF. Medium format. A film or digital sensor size that’s larger than 35mm full-frame (24mmx36mm) but smaller than large-format (4inx5in).

MFT (or M4/3). Micro Four Thirds. A mirrorless interchangeable lens digital camera system standard launched by Olympus and Panasonic in 2008 and joined by a large number of camera manufacturers. The specification uses the Four Thirds sensor size while omitting a mirror box and pentaprism to allow for smaller cameras and lenses.

MILC. Mirrorless interchangeable-lens camera. Also called EVIL (electronic viewfinder, interchangeable lens), CSC (compact system camera), and DSLM (digital single-lens mirrorless), this is a digital camera that uses removable lenses on a camera body that doesn’t contain a reflex mirror or optical viewfinder (like a DSLR does).

MLU. Mirror lock-up. A feature in single-lens reflex (SLR) cameras that allows the photographer to flip the mirror up and lock it in that position in advance of the shutter being triggered. This reduces camera vibration during the capture of a photo (thereby reducing blur) and also allows the mounting of lenses that extend further into the camera’s mirror box.

MP. Megapixel. One million pixels. A term used to refer to the resolution of a photos, displays, and camera sensors.

MS. Memory Stick. Sony’s proprietary removable flash memory card format that was originally introduced in 1998. In addition to the original Memory Stick, the family also includes the PRO, Duo, Micro, and PRO-HG. This format has been largely phased out after the rise of SD memory cards.

MTF. Modulation transfer function. A technical way to measure a lens’ optical performance potential. An MTF chart plots the contrast and resolution of a particular lens, with the x-axis representing the distance from the center of the frame (center at left and edge at right) and the y-axis representing light transmission (0% at bottom and 100% at top). MTF charts generally plot sagittal and meridional lines for the contrast measurements of lines that run parallel or perpendicular (respectively) to the line from the center to the edge of the frame.

MUP. Mirror up. Nikon’s name for mirror lock-up in its SLR cameras. See MLU.

N

ND. Neutral density. A type of filter that reduces the amount of light entering the camera, modifying the intensity of all wavelengths equally so that there are (ideally) no changes in color. Allows photographers to use exposure settings that would otherwise result in overexposed photos (e.g. for a longer exposure or larger aperture on a bright sunny day).

NR. Noise reduction. Digital processing to remove noise from a photograph, whether done in-camera by firmware or by a feature/tool in an image processing/editing application.

O

OCF. Off-camera flash. The use of flashes or strobes placed away from the top of the camera, where hotshoe-mounted or built-in flashes are located. This allows the photographer to creatively control the direction and intensity of light from each flash.

OEM. Original equipment manufacturer. The company that manufactured any given product, whether that product was marketed under that company’s or another company’s branding.

OIS. Optical image stabilization. Also known as image stabilization (IS) and optical stabilization (OS), this is a mechanism in lenses that compensates for camera movement while an exposure is being made by moving optical elements to vary the optical path to the sensor.

OOF. Out of focus. When some or all of a photograph is blurry due to the subject being found outside the depth of field, range of focal plane distances in which subjects are rendered as acceptably sharp in a photo.

OVF. Optical viewfinder. Allows the photographer to compose (and usually focus) a scene while looking at the scene itself rather than an electronic display (as with an EVF). This can be a through-the-lens viewfinder (like in SLRs) or a look-through viewfinder (like in rangefinders).

P

P. Program. A camera mode in which the camera calculates the optimal shutter speed and aperture (and optionally ISO). Program mode differs from Auto in that settings other than exposure are manually set by the photographer.

PASM. Program, aperture priority, shutter priority, and manual. The four main modes offered on cameras for determining which parameters of exposure are manually selected by the photographer versus which are automatically chosen by the camera.

PC. Prontor-Compur. A standard 3.5mm (1/8″) electrical connector used in photography to synchronize a shutter to a flash.

PDAF. Phase-detection autofocus. A camera autofocus system that divides incoming light from opposite sides of the lens into two images and compares them to calculate whether the subject is front- or back-focused. This information is then used to adjust the lens until focus is achieved.

PF. Purple fringing. An optical aberration, particularly in digital photography, in which a subject has a purple or magenta fringe.

PNG. Portable Network Graphics. A raster-graphics file format that was created as a replacement for the GIF. PNG images support lossless data compression and millions of colors (by comparison, GIF images are limited to a pallet of just 256 colors). Since the PNG was designed for the Web and not for print, only RGB color spaces are supported (and not CMYK).

PP. Post-processing. Also referred to as “post,” this is the process of editing original camera data with software programs (e.g Photoshop and Lightroom) to create an improved and/or customized final photograph. This can involve both basic edits (e.g. brightness, contrast, white balance, saturation, cropping) as well as more involved editing (e.g. cloning, compositing, masking).

PPI. Pixels per inch. A way to measure the resolution of a digital display. Refers to the number of pixels that are found space of one linear (not square) inch.

P&S. Point-and-shoot. A small compact camera, generally used with full automation to simplify operation for casual photo taking.

PS. Photoshop. The photo and raster graphics editing program made by Adobe. First released in 1988, Photoshop has become the industry standard application for photographers. The software is so ubiquitous that its name has become a generic word for all photo editing (e.g. “that image was photoshopped”).

PSE. Photoshop Elements. The photo and graphics editor made by Adobe geared toward hobbyist photographers. While it contains many of the same core features of Photoshop, it is mainly geared toward fast and simple editing by those who are not experts and professionals.

PZD. Piezo Drive. Tamron’s name for its ultrasonic motor lens technology used in smaller lenses. See USM.

Q

R

RAW. Not an acronym but widely capitalized as though it were, including by companies like Canon. A raw image file is one that contains minimally processed data straight from a digital camera sensor (or scanner). These files are generally processed in raw editing software before being converted into a format such as JPEG or TIFF for printing or sharing online. Many camera manufacturers use proprietary raw file formats in their camera ecosystems, while others use open formats such as Adobe’s DNG.

RGB. Red, green, and blue. An additive color model in which the primary colors of red, green, and blue are added together in various proportions to create a wide range of possible colors. As an additive model, red, green, and blue are added to black, and the full combination of colors is white. Digital cameras and computer/phone displays typically work in RGB.

S

S. Shutter priority. Also abbreviated on some mode dials as Tv, for time value, this is a camera setting in which the photographer chooses a fixed shutter speed while allowing the camera to adjust the aperture value (and possibly ISO) to achieve a proper exposure (as determined by the camera’s internal light meter).

SD. Secure Digital. A memory card format that is commonly used by digital cameras. Introduced in August 1999 by SanDisk, Panasonic, and Toshiba, it uses flash memory technology to store large amounts of data on relatively small devices. Its primary competitor is the CompactFlash (CF) card.

SDA. SD Association. The non-profit organization formed in January 2000 by SanDisk, Panasonic, and Toshiba to manage SD Card standards. Around 1,000 companies are now a part of SDA.

SDM. Supersonic Dynamic Motor. Pentax’s name for its ultrasonic motor lens technology. See USM.

SOOC. Straight out of camera. Photos as they were captured by the camera without any additional post-processing afterward prior to it being displayed.

SLR. Single-lens reflex. A camera (most often referring to a film one these days) that uses a mirror to direct light between the viewfinder prism (for seeing and composing the scene) and the image sensor (when the shutter is activated to expose a photo).

SSM. Super Sonic Wave. Sony/Konica/Minolta’s name for its ultrasonic motor lens technology in a ring motor. See USM.

STM. Stepper Motor. Canon’s lens motor design introduced in 2021 that converts small digital signal pulses into a smooth mechanical rotation for autofocusing a lens. This technology allows lenses to focus smoothly and quietly, which is particularly beneficial for video recording.

STU. Shoot through umbrella. A white translucent umbrella through which a photographer can fire a flash for diffuse light on a subject.

SWD. Supersonic Wave Drive. Olympus’ name for its ultrasonic motor lens technology. See USM.

SWM. Silent Wave Motor. Nikon’s name for its ultrasonic motor lens technology. See USM.

T

TB. Terabyte. A multiple of the byte unit for digital information storage. Since tera denotes 10¹², a terabyte is one trillion bytes of data.

TC. Teleconverter. An accessory that fits between a camera and lens to extend the focal length of the attached lens, typically by 1.4x or 2x. Tradeoffs generally include less light transmitted, poorer image quality, and slower autofocus.

TIFF. Tag Image File Format. Also abbreviated TIF, this is a file format for storing raster graphics images that is commonly used in photography. TIFF files can store photos in a lossless format, meaning image quality is not lost when images are edited and resaved, making it popular as an archival format.

TLR. Twin-lens reflex. A type of camera that uses two lenses of the same focal length. One of the lenses is used for the viewfinder system while the other is used to capture the photograph.

TTL. Through the lens. A method of metering light in which the intensity of light that’s reflected from the scene is measured through the lens, as opposed to having a separate light detector or an off-camera light meter. Also a flash mode that uses the camera’s built-in light metering to determine optimal flash output for the correct exposure.

TV. Time value. The setting on cameras for shooting in shutter priority mode. This allows the photographer to select the desired shutter speed while the camera selects the aperture required for correct exposure.

U

USB. Universal Serial Bus. The industry standard for cables released in 1996 that provide communication and power between devices such as computers and cameras. There are a number of common USB connectors, including USB-A, USB-B, Micro-USB, Mini-USB, and USB-C.

USD. Ultrasonic Silent Drive. Tamron’s name for its ultrasonic motor lens technology generally used in larger lenses. See USM.

USM. Ultrasonic motor. A type of piezoelectric motor commonly found in camera lenses that uses ultrasonic vibrations to move lens elements for autofocusing. It has the advantage of being faster and quieter than other types of motors used for focusing. Canon pioneered this technology and offers it under the USM label, but it is found in the industry under a number of names (e.g. Sony SSM, Nikon SWM, Olympus SWD, Panasonic XSM, Pentax SDM, Sigma HSM, and Tamron USD).

UV. Ultraviolet. Electromagnetic radiation with a wavelength between 10-400nm, which is shorter than visible light (which is between 400-700nm. These wavelengths can be captured by special or modified cameras in a niche known as UV photography.

V

VR. Vibration Reduction. Nikon’s name for its image stabilization technology in lenses that reduces blur caused by camera shake.

W

WB. White balance. The adjusting of color intensities in a scene that have a color cast caused by different light sources with different color temperatures. The goal is usually to reach natural/correct colors that reflect what the human eye sees.

X

XQD. XQD (Not an acronym). A memory card format designed as a replacement for CompactFlash cards. Uses PCI Express for its data transfer interface and is primarily targeted at high-resolution still and video cameras. The format was first unveiled by SanDisk, Sony, and Nikon in November 2010.

XSM. Extra Silent Motor. Panasonic’s name for its ultrasonic motor lens technology. See USM.