photography
Full frame
High-end DSLRs' and mirrorless cameras' image sensors are the same or nearly the same size as a standard 35mm frame of film, hence the name "full-frame" sensors. The focal length of lenses on smaller cameras is often translated into full-frame equivalents in order to make comparisons.
Face recognition
Many cameras have the ability to recognize a person's face (or multiple faces) when you're shooting a portrait, group shot or other scene, and set those as the points for optimal focus and exposure.
High dynamic range
Most digital camera image sensors cannot capture the full range of brightness (i.e., from shadow to highlights by midday sun) that the human eye can. HDR helps capture that range of brightness by taking several quick shots of the same scene, but with slightly different exposure settings, and then combining them.
HD video
Most new digital cameras are capable of recording high-definition video, at a resolution of at least 1280 x 720 pixels (720p). Increasingly more cameras can capture video at 1920 x 1080 pixels, known as 1080p or full HD. And some can even capture video at 3840 x 2160 pixels, known as 4K or Ultra HD.
4/3 sensor
A 4 x 3 aspect-ratio sensor that's roughly one-quarter the size of a 35mm film frame.
4/3 format
A camera format based on a sensor with a 4 x 3 aspect ratio that allows for interchangeable bodies and lenses among several manufacturers. Olympus and Panasonic are the main makers of 4/3 format bodies, while five other companies (including Leica and Sigma) produce lenses.
Phase-detection autofocus
A commonly used autofocus technology that measures where beams of light from different parts of the lens land on a series of sensors. Seeing where the light falls allows the camera to calculate the position of the lens required to achieve focus on the image sensor. This method is generally faster than contrast detection. Once found only in DSLRs, it's now making its way into mirrorless cameras and even cellphones.
F-stop
A diaphragm inside the camera lens, known as the aperture, can be opened or nearly closed, to regulate the amount of light that falls on the image sensor. The ratio of the lens's focal length to the diameter of the opening is the f-number, or f-stop. Due to the way the values are calculated, the smaller numbers (f1.2, f2.4) actually represent wider openings. Each full f-stop represents a doubling or halving of light. For this reason, photographers often describe shutter speeds in f-stops as well. For example, a shutter speed of 1/60 second is one stop less than 1/30 second.
Live view
A feature built into almost all digital cameras and video cameras that allows the user to preview the subject on an electronic screen or in an electronic viewfinder in real time before snapping a photo or starting to record video.
RAW
A file format, usually proprietary to each camera manufacturer, that stores all the captured image data without compression. RAW files are usually processed outside the camera in editing software such as Photoshop. Compared to the compressed JPEG, the RAW file contains significantly more data, such as greater bit depth, and can be useful for "rescuing" shots that may have color issues or incorrect exposure. Cameras that allow images to be saved in the RAW file format can also be set to simultaneously capture JPEGs, so the user has the option of which format to use for each picture.
Macro lens
A lens specifically designed to shoot close-ups (4 inches or nearer) with little or no distortion. It's also known as a flat-field lens.
Normal lens
A lens that captures the same perspective as the human eye. On a full-frame camera, the normal lens is roughly 50mm. On a camera with an APS-C image sensor, a normal lens is about 35mm, and on a camera with a 4/3 sensor, it's about 25mm.
Telephoto lens
A lens with a long focal length (greater than 50mm on a full-frame camera) that brings the subject or action closer than it appears to the naked eye.
Prime lens
A lens with a single focal length, be it wide, normal or telephoto. Compared to a zoom lens, a prime lens of commensurate quality is generally cheaper, faster (allows more light to pass) and produces less distortion.
Memory Stick memory card
A memory card designed by Sony, and used almost exclusively in Sony digital cameras.There are different types of Memory Sticks - Standard, Pro, Duo, Duo-Pro, and Magic Gate. Confusing, isn't it! To make matters worse, they are not necessarily interchangeable. If you need to buy a memory stick for your digital camera check very carefully the type it uses. Sony Memory Sticks are now quite rare. Sony now uses more standard memory card formats, such as SD cards.
Aperture priority
A mode (abbreviated AV) available on nearly all advanced and some point-and-shoot digital cameras that allows the user to set a specified aperture value (in f-stops). The camera automatically adjusts the shutter speed to achieve proper exposure for the selected aperture.
Noise
A mottled or grainy appearance in images caused by electrical fluctuations on the image sensor. Noise becomes more pronounced as the camera's ISO (light sensitivity) is raised, causing decreased detail and distorted colors. Noise is not always visible in small versions of photos used for online posting but can become obvious in large prints or cropped photos.
Time exposure
A photo in which the camera's shutter remains open for more than a fraction of a second — usually, between 1 and 30 seconds. Time exposure can be used to record a very-low-light scene with stationary objects to bring out the details. Moving objects will record as a partial or complete blur or streak, which helps convey motion or an expanse of time. Some astronomy time-exposure shots can take hours.
Diffuser
A piece of opaque plastic that sits over the top of a flashgun. It's job is to soften the light from the flashgun, and therefore reduces harsh shadows caused by a 'bare' flash
Megapixel
A pixel, also called a picture element, is the smallest part of an image that can display full color. Even the smallest image sensors now create images with millions of pixels, known as megapixels. A higher number of megapixels is not necessarily better; it simply refers to the amount of detail that can be recorded, not the quality or accuracy of the image itself.
Compact Flash (CF) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Currently the majority of memory capacities freely available range from 4GB to 32GB. The larger capacity cards are really of use to professionals only. CF cards are the largest of the popular format memory cards. These days they are used mostly in larger digital cameras, rarely compact consumer cameras.
Secure Digital (SD) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Popular memory capacities these days range from 2GB to 32GB. Some SD cards have a clever feature where part of the card can flip up; this allows the card to be inserted into a USB port on a computer - images can be transferred to the computer without the need for a card reader or any special cables. SD memory cards are also used extensively in mobile phones, although they are in a smaller format. The smallest are SD Micro cards. They come in memory capacities from 2GB up to 16GB, and are smaller than a fingernail (make sure you don't drop it when inserting it!)
1-inch sensor
A relatively large image sensor used in advanced, compact Nikon, Sony and Samsung digital cameras. It's only 13 percent the size of full-frame sensors found in pro cameras but much bigger than you get in a standard point-and-shoot or cellphone camera.
Interval photography
A setting found on many advanced still and video cameras that allows the user to program a camera to take photos or video frames at regular intervals — typically from once per second up to once per hour — to achieve a time-lapse effect.
Pixel
A small dot in a digital photography image. Thousands of pixels make up a digital photograph.
Extreme Digital (xD) memory card
A small memory card (smaller than SD cards) introduced by Fuji and Olympus. They are designed specifically for digital photography (other memory cards were designed simply as data storage devices). They are not as widely used as either CF or SD cards.
Memory card
A tiny, flat, solid-state electronic device that records digital data. Most digital cameras and video recorders save the images or clips onto the SD (secure data) card. The larger CF (compact flash) card is found in many "pro" DSLR models. Each card can typically hold between 1GB and 64GB of data, or anywhere from 25 to 1,500 images or 5 minutes to an hour of video.
Foveon Sensor
A type of sensor where the colour recording layers are stacked on top of each other. This means that every "pixel" can record the level of red, green and blue light hitting it. This differs from the bayer sensor, where each pixel can record only one colour of light.
Moiré
A wavy pattern that can appear when the object being photographed has repetitive details that exceed the resolution of the image sensor. Intricate fabric weaves, the screens in windows and even hair can produce moiré.
Stereoscopic photography
A way of producing 3D images from 2D photography. Not strictly digital photography terminology, although the effect is easier to achieve in digital photography than in film photography. Two photos are taken at the same time, by two separate cameras that are set a short distance apart. The resulting images are then swapped (i.e. the photo taken by the left-hand camera is placed to the right-hand side of the other image) before viewing.
APS-C
Advanced Photo System-Classic is an image sensor roughly one-third to one-half the size of a 35mm frame of film, or full-frame image sensor. APS-C image sensors are used in most consumer-level DSLRs and in many mirrorless cameras.
Sensor cleaning
All image sensors hold an electrical charge, which attracts dust and, in turn, hurts image quality. This is a problem for interchangeable-lens cameras, whose internals are exposed to the air during lens swapping. Many DSLRS and mirrorless cameras have a self-cleaning mechanism that vibrates the image sensor to shake off dust.
Programmable menu
Also called Custom Functions (CF). On better digital cameras, the user has the option to select a variety of settings — ISO, shutter priority, aperture priority, exposure compensation, focus mode — and save them as the default values when the device is turned on.
Photosite
Also called a photoreceptor, it is a tiny well on an image sensor that collects photons of light and measures the brightness of red, green or blue light falling into it. Data from these three colors is combined to produce the pixels that make up a digital image.
Optical low pass filter
Also called an anti-aliasing filter, it's an ultrathin piece of glass or plastic mounted in front of, or bonded directly to, the image sensor. The OLPF blurs the image very slightly, to help break up the tendency of an oversharp image to produce false colors and moiré (herringbone-like patterns). Some new cameras with high megapixel counts (20 or greater) eschew OLPFs to help increase sharpness.
Chromatic aberration
Also known as "color fringing," this distortion appears when the camera lens fails to focus on all the colors where two points of high contrast meet (such as where the dark roof of a building meets the sky). Chromatic aberration appears as green or purple fringing at the point of contrast.
Point-and-shoot
Also known as P&S, these are simple cameras in which the only tasks needed to take a photograph are to turn on the unit, point it at the subject and press the shutter button. Even most sophisticated, semi-pro and professional cameras have an Auto function that's essentially a P&S mode. Point-and-shoot has come to denote relatively small cameras that don't accept interchangeable lenses, even though some of them may offer advanced features and control options.
Mirrorless camera
An advanced type of digital camera with an interchangeable lens system that eschews the mirror viewfinder system found in DSLRs in order to be smaller and lighter. Instead, mirrorless cameras display an image preview on an LCD or OLED screen. Many mirrorless cameras have only a rear screen for previewing photos, similar to a point-and-shoot or cellphone camera. More-expensive models also have electronic viewfinders that make them more like DSLRs.
Shutter priority
An exposure mode on an automatic or autofocus camera that lets you select the desired shutter speed; the camera sets the aperture for proper exposure. If you change the shutter speed, or the light level changes, the camera adjusts the aperture automatically.
Noise reduction
An operation in the image processor that improves a noisy image by targeting and eliminating stray unwanted pixels (usually colored dots that are very different from the dots surrounding them). Noise reduction also removes some detail, however.
Focal length
An optical measurement that determines how much of what you see in front of you is captured by your camera's lens. A short focal length, such as 24mm, captures wide angle; a long focal length, such as 100mm, is telephoto. A "normal" focal length (50mm on a full-frame or film camera) roughly approximates how far away things appear to the naked eye. Focal length does not describe the physical size of the lens itself, but rather refers to its magnification.
Viewfinder
An optical or electronic eyepiece that allows the photographer to preview, focus and frame the subject. Electronic viewfinders (EVFs) also allow a photographer to monitor video being shot.
Fisheye lens
An ultrawide-angle spherical lens that can capture up to a 180-degree field of view, or just about everything you can see in front of you. However, the image will be distorted, like looking through a goldfish bowl. Sometimes, this distortion is left as an artistic effect; other times, it can be minimized using image-editing software.
Bokeh
Bokeh is a photography term that refers to the way a lens blurs an image. Generally it is considered good practice, especially with potrait photography, to have the main subject in focus and the background blurred. Bokeh refers to how evenly and pleasingly the out of focus (blurred) area looks.
Cross Processing
Cross processing is an old film term. It refers to the practice of deliberately developing film in chemicals intended for a different type of film. For example, developing a slide film using print film chemicals. The result is un-natural colours and contrasts. In digital photography the effect can be achieved (and is easier to control) using software.
Interchangeable lenses
DSLR and mirrorless camera lenses can be removed, allowing the photographer to choose the best lens for a particular type of shot.
Film Grain
Film grain is not really digital photography terminology - the digital photography equivalent is noise. Film grain is the small speckles that show up on photographs. Film contains tiny granules of light sensitive material. The more sensitive the film is, the larger these granules are. When a film negative (especially from sensitive film) is enlarged onto photographic paper (in order to make a print), the tiny grains get enlarged too, and become visible. The effect of film grain is often considered to be artistic, and it is sometimes put back into digital images (using software) for artistic purposes.
Wide-angle lens
Has a short focal length (less than 50mm on a full-frame camera) to capture a wider field of view.
ISO
ISO is a term "borrowed" from film photography. In film photography the ISO was a measure of how sensitive film was to light. It was called film speed. The higher the number, the more sensitive it was (and the film was called "fast film"). E.g. ISO 100 was not that sensitive, ISO 1600 was very sensitive. In digital photography the number (still called "ISO") refers to how sensitive the image sensor is to light. By making the sensor more sensitive to light, photos can be shot with higher shutter speeds and/or in lower light.
Image editing software
Image editing software is used to manipulate a photo once it has been taken. Digital cameras store images as files on memory cards. Once downloaded to a computer these files can be edited using image editing software. Editing can be used to improve a photo (for example, improving the contrast and then sharpening the image), or can be more extreme (for example, cutting a person out of one photo and pasting them into a different photo).
Optical viewfinder
In a DSLR camera, it's the combination of a movable mirror and a pentaprism or additional series of mirrors that allows the photographer to see through the main lens in order to view and frame the subject.
Blown Highlights
In digital photography terminology, blown highlights are areas of a photo that are so bright they are pure white. A digital camera can record 256 shades of brightness, from "0" (pure black) to "255" (pure white). Every pixel captured is assigned a brightness value. When it comes to editing, software can add to, or subtract from this value to make a photo brighter or darker. E.g. it can add "10" to every pixel to make the photo brighter. However, if a pixel already has the value of "255", it can go no higher. No detail can be found in these areas of a photo and they end up pure white. These areas are called blown highlights.
Purple Fringing
In digital photography terminology, purple fringing is an undesirable purple "rim" that surrounds areas of high contrast in a digital image.It's very obvious when photographing people against a bright (but not deep blue) sky. The reasons for purple fringing aren't clear, although it is generally accepted that poor quality lenses and poor quality sensors make it worse.
Resolution
In digital photography terminology, resolution is a measure of the number of pixels there are on a sensor. The resolution of digital cameras is measured in "megapixels" - millions of pixels. It works by a simple bit of maths - multiply the number of pixels along the bottom of the sensor by those up the side. For example, a sensor with 3000 pixels along the bottom, and 2000 up the side equals 6,000,000 pixels in total. That would make it a 6 megapixel camera.Theoretically it is possible to change the sensor in a digital camera (say, to upgrade a 5 megapixel sensor to a 10 megapixel sensor). In practice though, so much of the camera would have to be replaced it makes this impossible to do.
Shutter Delay
In digital photography terminology, shutter delay refers to the time between pressing the shutter button to the camera actually taking the picture. It is not a term used in traditional photography because the delay was negligible. To overcome the problem of shutter delay most digital cameras allow you to pre-focus by pressing the shutter button halfway, and once the focus has been locked the shutter can be pressed fully. The problem is less apparent with digital SLRs.
Shutter Speed
In digital photography terminology, shutter speed is slightly different to traditional photography. Traditionally, the shutter opened when you pressed the camera's button, exposed the film behind the shutter, and then closed again; covering the film back over in the process.With electric sensors the "shutter" is controlled by the camera's computer. A short shutter speed means the sensor is charged for a fraction of a second. For longer shutter speeds, the sensor is kept charged for longer.The shutter noise in most compact digital cameras is created by a small speaker in the camera and mimics a real shutter. It has its use - it lets you know when the photo has been taken.Digital SLRs have no need to mimic a shutter as they work with a combination of shutter and electrically controlled sensor.
File format
In film photography photos are recorded onto light sensitive film. This is developed with special chemicals and a negative is produced. In digital photography photos are stored as a digital file. You need to decode the file in order to view it (see this section of the history of digital photography for more). There are different types of file formats used in digital photography. Some are lossy and some are lossless. The most common lossy file format used in digital photography is JPEG. The most common lossless file format used is TIFF. Increasingly becoming common are lossless RAW files.
Vignette
In photography, a vignette is when the edges of an image are either darkened, or lightened, in relation to the rest of the photo. It has the effect of drawing the viewer "into" the photo.The vignette can be caused accidentally by obstructions (for example, the lens hood) creeping into the frame at the edges. Or, as is more common in the digital age, a vignette is applied to an image after the photo has been taken using software.
Aperture
In photography, an aperture is an adjustable opening in the lens that regulates how much light passes through. Aperture controls depth of field - how much of the image, from foreground to background, appears sharp. A large aperture allows in both light rays directed straight at the lens (which produce a sharp image) and those coming in at angles (which appear blurry). The smaller the aperture, the fewer of these off-angle light rays enter the lens, allowing more of the image to appear sharp. Aperture is measured in a unit called f-stops, in which smaller numbers actually represent larger openings. An aperture of f1.4 (which only a few lenses can achieve), for example, is a very wide opening that puts very little of the image in focus. An aperture of f/32 (also rare) makes essentially everything in a sweeping landscape sharp.Between those extremes are aperture values that produce varying depth of field.
Post Processing
In the days of film photography this referred to work done in the darkroom. Not simply developing the photos, but relating more to correcting colour casts, lifting dark areas of a scene, adjusting the contrast - that sort of thing. In digital photography terminology however, post processing means adjusting your digital photos using image editing software - Photoshop, for example. The same adjustments that were made in film can be reproduced with software.
Light metering
Light metering is the practice of measuring the light on a subject to determine exposure settings (aperture, shutter speed, ISO). Sensors inside digital cameras measure the amount of light reflected from the subject to automatically set exposure, but the readings can also serve as a guide for photographers operating a camera manually.
Lenses
Not specifically digital photography terminology, but still relevant to digital cameras, especially DSLRs. When using a DSLR it is possible to change the lens on the camera.The job of the lens is to throw a circle of focused light onto the image sensor. In the days of film cameras that meant the light fell onto the film. With digital photography the light hits the image sensor. Image sensors are usually smaller than a 35mm frame of film. This means the circle of focused light can be smaller too. Specific "digital only" lenses will throw a circle of focused light that will cover a digital camera's sensor, but is too small to cover a 35mm frame. They are therefore only suitable for use on digital cameras.
Macro
Not strictly digital photography terminology, "macro" means the ability for a camera (or lens) to focus so near to the subject that it is captured life size on the image sensor. The term macro is used more loosely these days, and usually refers to the ability to get close up shots (not necessarily life size). Typical macro subjects are flowers and insects.
Hot Shoe
Not strictly speaking digital photography terminology, but a hot shoe is the special slot on the top of a camera that can accept camera accessories, usually a flashgun. They are uncommon on compact digital cameras and are usually found on digital SLRs (DSLRs). Unfortunately every manufacturer has their own design of hot shoe, so if you buy a flashgun for, say, a Canon DSLR; and then in the future go out and buy a Nikon DSLR your old 'Canon' flashgun won't work on your new Nikon camera.
Backside illuminated sensor
Often abbreviated as BI or BSI, it's a type of image sensor designed to absorb more light in dim conditions. BSI is usually found in smaller sensors, such as those in some Nikon and Samsung mirrorless cameras, Sony point-and-shoot cameras and various smartphones, such as newer Apple iPhone and Samsung Galaxy S models.
Scene modes
On most point-and-shoot cameras, as well as many DSLRs and mirrorless models, users can select modes with optimized settings for taking specific kinds of photographs, such as portraits, landscapes or night shots.
Crop factor
Originally, lenses on SLRs were designed to cover a full frame of 35mm film (1 x 1.5 inches), but most DSLR and mirrorless camera image sensors are smaller than a frame of 35mm film. When this occurs, the image they capture is cropped to the center of the image, effectively producing a higher level of zoom. Most of the dominant APS-C sensors, for example, have a 1.5X crop factor. A 50mm lens that works for portraits on a high-end camera with a full-frame sensor would be the equivalent of a slight telephoto 75mm lens on an APS-C camera.
Polarizing filter
Polarizing filters attach to the end of a camera lens (usually, but not always, a digital SLR) and are designed to cut out light from a particular direction, for example, reflections from water or glass. The effect is impossible to achieve using software; polarizing filters therefore need to be used when the photo is taken, not applied at the post processing stage.
Bracketing
Setting a camera to automatically take two to six quick shots with a change in a single setting to increase the chance of getting a perfect shot. The most common kind of auto-bracketing is exposure bracketing, but ISO, white balance, flash and focus can also be bracketed in many cameras.
TIFF
Short for Tagged Image File Format, this image file stores all the data of an image in a "loss-less" format that allows the file to be smaller than RAW files but more detailed than JPEG images.
CCD
Short for charged coupled device, a CCD is a sensor type that reads data in a way that avoids the stuttering or distorted look of fast motion in video that results on some cameras. CCD sensors were once the most common in digital cameras, but the affordability and higher quality of CMOS image sensors for still photography has allowed them to mostly replace CCD sensors.
CMOS
Short for complementary metal oxide semiconductor, CMOS is now the most popular type of image sensor and can be found in everything from cellphones to pro DSLRs. Its low-light sensitivity and ability to provide live preview and video capture to DSLRs have made it extremely popular.
SLR
Short for single-lens reflex, an SLR is a film camera in which a mirror reflects incoming light from the lens into an optical viewfinder, allowing the photographer to preview and frame a shot. When the photographer presses the shutter button, the mirror instantly swings up, and the shutter opens, exposing the film to the light from the subject. Its electronic equivalent is the DSLR, or digital single-lens reflex camera.
Bayer pattern
The "Bayer" pattern is digital photography terminology to describe how photosites are arranged on an image sensor. A Bayer pattern has 50% green photosites, 25% red photosites and 25% blue photosites. There are twice as many green photosites than red or blue because human eyes are most sensitive to green light.
HDMI
The High-Definition Multimedia Interface is the most common cable and port for transmitting HD video and digital audio between consumer devices such as game consoles, set-top boxes and HDTVs. Many digital cameras have a mini-HDMI jack that allows them, with an adapter cable, to send HD video directly to a TV.
JPEG
The Joint Photographic Experts Group file format is the most popular for storing digital images from a camera. To speed up operations, as well as save storage space, JPEG images are compressed; the degree of compression determines the quality of the image. JPEG image quality is not as good as when the image data is saved without compression (RAW). However, the RAW file format requires more storage space, takes longer to capture and process, and is not standard (each camera manufacturer has its own version).
Panorama
The ability found on many cameras, as well as in image-editing software, to seamlessly "stitch" together a series of adjacent shots, each taken at a slightly different angle, into a single, ultrawide-angle photograph with up to 360-degree coverage.
Sensor
The electronic chip that records the image in a digital camera. They come in two main types. CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are the most common. CCDs are used almost exclusively in compact cameras, CMOS sensors are used in larger, and more expensive DSLRs. There are other types, but not well used. JFET (Junction Field Effect Transistor) - developed by Nikon and used in a very small number of their cameras. X3- a new type of sensor developed by Foveon. Used only in Sigma DSLRs and a couple of Polaroid compact cameras.
Image sensor
The heart and soul of every digital camera, it's the silicon chip (generally using CMOS but sometimes CCD technology) that captures the picture or video you're shooting.
Histogram
The histogram is a visual representation of how the highlights and shadows are distributed in your scene, with the edges representing the extreme highlights on the right and shadows on the left. Ideally, it should display as a bell curve, with most of the scene falling in a middle level of brightness. A histogram skewed toward the light or dark side of the range can indicate if your picture will be too contrasty, dark, flat or overexposed. Many cameras can display a histogram in the image preview so you can adjust settings beforehand. The image playback mode on the camera, as well as photo-editing programs, often display the histogram as a guide to the edits that will improve the look of the photo.
Bit depth
The level of gradation used to define a shade of dark or light. Higher bit depth allows more accuracy and fidelity of captured images, and allows finer adjustments when editing. Most point-and-shoot cameras capture 10-bit or 12-bit images, while better DSLRs and mirrorless cameras capture at 12-bit or 14-bit.
Zoom lens
The most common kind of lens used on digital cameras, a zoom lens moves to change its focal length and cover a range of perspectives, often from wide-angle to telephoto, keeping in focus through the entire range. The trade-off is that zoom lenses are usually heavier and slower (i.e., don't let in as much light), and they may introduce more image distortion than prime lenses, which have a fixed focal length.
Light metering modes
The most typical metering modes are spot, in which a small cluster of sensors in the middle of the frame determines the amount of light falling on the subject; center-weighted, which measures half the light from the spot and half from the corners and averages them; and matrix metering, which measures a number of points throughout the frame and averages them.
Lens mount
The opening on the front of a DSLR or mirrorless camera into which an interchangeable lens is fitted. In general, each camera maker has its own lens-mount style, though micro 4/3 mounts are the same, allowing those cameras to share lenses.
Depth of field
The part of an image, from foreground to background, that is in focus. A shallow depth of field, appropriate for portraits, shows only a small portion in focus. Adjusting aperture is the main way to control depth of field. Large apertures of f1.4, f2.0 or f2.8 produce limited depth of field, whereas smaller ones such as f11, f16 or f22 are used for greater depth of field. A deep depth of field, often used for landscapes and group shots, captures virtually everything in sharp focus.
Self-timer
The setting on almost every camera that delays taking the shot for a few seconds (usually 2 to 4 seconds or 10 seconds) after the user presses the shutter button. Its purpose is to give the photographer time to get into the picture, or to guarantee a steadier shot by avoiding having the photographer jar the camera when pressing the shutter button.
Exposure compensation
The setting on just about all advanced and even some P&S digital cameras that allows the user to adjust the shutter speeds for a desired effect (such as a fast speed to freeze action). In shutter priority, the camera adjusts the aperture (f-stop) to produce proper exposure at the user-selected shutter speed. Some camera makers abbreviate shutter priority as "TV," for time value, on the camera's mode dial.
DSLR
The successor to the film SLR, a digital single-lens reflex camera uses a movable mirror along with a prism or additional mirrors to reflect an image from the lens into a viewfinder, so you can accurately frame and focus your shots. When you press the shutter button, the mirror flips up, allowing light to pass from the lens onto the image sensor, which records the photo.
Contrast detection autofocus
This AF technology uses light sensors behind the lens, usually on the imaging chip itself, to measure when contrast is at its greatest point, which corresponds to maximum sharpness. It's generally slower than a rival technology, phase detection. Contrast detection AF is found in most point-and-shoot, cellphone, bridge and mirrorless cameras, as well as in video cameras. DSLRs also use contrast detection when they shoot in live view mode.
Bridge camera
This camera type falls between simple point-and-shoots and DSLRS or mirrorless cameras in both size and capabilities. They generally incorporate some advanced features — such as larger sensors, more powerful processors or sophisticated controls — but their lenses are not removable. Some bridge cameras have very long zoom lenses; 30X or greater is not uncommon.
Program mode
This common mode on cameras automates aperture and shutter speed while giving you control over white balance, ISO, flash and other settings.
Micro 4/3
This is an implementation of the 4/3 sensor format (originally used in DSLRs) for mirrorless cameras.
Optical image stabilization
This technology helps counteract the jittery motion caused by handholding a camera, which can result in blurred images at low shutter speeds (roughly below 1/60 second). Sensors detect movement and instantaneously signal the image sensor or a lens element to move in the opposite direction, canceling out the movement. A good IS system can allow the user to decrease the shutter speed by a factor of three (aka three stops) and still get a crisp image. Camera makers have different names for the technology, such as IS for Canon, VR for Nikon and SR for Pentax. [LD2]
White balance
To the human eye, white is white, whether it's being illuminated by the sun, a cloudy sky, a fluorescent tube or a tungsten light bulb. But to image sensors, that white may have a yellow, blue or green cast. White balance is an automatic or manual adjustment to a digital camera's color readings so whites appear to be white (and all other colors are also accurate) regardless of the illumination source.
Shutter
Traditionally, this is a mechanical curtain that opens and closes to expose the image sensor. Many digital cameras have an "electronic shutter." The camera collects data from the sensor for a specified amount of time, corresponding to how long a mechanical shutter would expose the sensor. While high-end DSLRs and mirrorless cameras may feature both types of shutters, many point-and-shoots and lower-end cameras use an electronic shutter exclusively. Typical shutter speeds for consumer cameras range from 1 second to 1/4000 of a second, though longer (30 seconds) and shorter (1/8,000 of a second) speeds are featured on some models. Longer (slower) shutter speeds allow more light to reach the image sensor, which can be good for night shots but increases the chance of motion blur. Shorter (faster) shutter speeds can freeze fast action.
Electronic viewfinder (EVF)
Unlike traditional DSLRs that use a mirror to reflect the image up to your eye, an electronic viewfinder is a tiny, high-definition LCD or OLED screen that provides a preview directly from the image sensor. It is found in some mirrorless and bridge cameras.
Metadata
When a digital camera captures an image it records two things in the file that is saved - image data itself, and data about that data (confusing, isn't it?). The "about the image" data is called "metadata". The information it contains varies from camera to camera, but typically includes, amongst other things, information such as date, time, shutter speed, aperture, ISO and file type. This information can be useful when trying to find photos later (because you can search for your images by date), and helps to improve digital photography because the photographer can work out what combinations of shutter speed and aperture work well.
Lossy/Lossless files
When a digital camera takes a photo, the image data is stored on a memory card as a computer file. If the data is stored fully, the file is called a lossless file. These files are quite large in size. The most common type of lossless file in use are TIFFs. To cut down on large file sizes, the camera can throw away parts of the data that the human eye probably won't notice anyway. These files are called lossy. The most common type of lossy file are JPEGs. Caution should be taken when using JPEGs if image quality is important
Flash modes
Your camera's built-in or external flash has a variety of settings, or modes, that help you perfectly illuminate your picture. TTL (through the lens) is the default mode, allowing your camera's processor to read the light when the flash comes on, and cut it off at the correct instant so it won't be underexposed or overexposed. Red-eye mode fires a brief light before taking the actual shot, to force your subject's pupils to constrict so they won't reflect red from their retinas back into the photo. Other modes include rear curtain sync, which fires late, to freeze the front of a moving subject while leaving a slight trailing blur behind it, and front curtain sync, which does the opposite.
