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Photography glossary
- Aperture
- The adjustable opening inside the lens that controls how much light passes through. It also shapes depth of field. Aperture and f-numbers →
- Aspect ratio
- The proportion of an image's width to its height, such as 3:2, 4:3, 16:9 or 1:1. Composition basics →
- Astrophotography
- Photographing the night sky, from the Milky Way and star trails to the Moon and deep-sky objects. Long exposure and the night sky →
- Moving autofocus from the shutter button to a rear button, so focusing and taking the picture are separate actions.
- Banding
- Visible steps instead of smooth gradients, often in skies, caused by too few tonal levels or heavy editing of 8-bit files. RAW vs JPEG and dynamic range →
- Base ISO
- The lowest native ISO of a sensor, where it usually delivers the cleanest image and widest dynamic range. ISO and image noise →
- Bit depth
- The number of tonal steps each colour channel can record. An 8-bit JPEG has 256 levels per channel; 12- or 14-bit raw files hold thousands. RAW vs JPEG and dynamic range →
- Blue hour
- The twilight period when the sun is just below the horizon and the sky takes on a deep blue tone. Golden hour and blue hour →
- Bokeh
- The look of out-of-focus areas in a photo, especially how blurred points of light are rendered. It depends on lens design and aperture shape. Focus and depth of field →
- Bracketing
- Taking several frames of the same scene at different settings, most often exposure, so you can pick the best or merge them later. What is exposure? The exposure triangle →
- Bulb mode
- A setting that keeps the shutter open for as long as you hold the button or remote, for exposures beyond the camera's longest timed speed. Shutter speed and motion →
- Chromatic aberration
- Coloured fringes along high-contrast edges, caused when a lens fails to bring all wavelengths to the same focus. A short history of camera lenses →
- Circle of confusion
- The largest blur spot that still looks like a sharp point at normal viewing size. It is the basis of depth of field calculations. Focus and depth of field →
- Circular polariser (CPL)
- A rotating filter that cuts reflections from water and glass, deepens blue skies and boosts colour saturation. Camera filters: ND, polariser and more →
- Clipping
- Loss of detail when tones are pushed past pure white or pure black. Clipped highlights cannot be recovered, even from raw files. Light metering and the histogram →
- Colour space
- A defined range of colours a file or device can describe, such as sRGB, Adobe RGB or Display P3. RAW vs JPEG and dynamic range →
- Composition
- How the elements of a picture are arranged inside the frame to guide the viewer's eye. Composition basics →
- Contrast-detection AF
- An autofocus method that moves focus back and forth until edge contrast peaks. It is precise but usually slower than phase detection.
- Crop factor
- How much smaller a sensor is than full frame, used to compare fields of view. A 50 mm lens on a 1.5× APS-C body frames like about 75 mm. Sensor sizes and crop factor →
- Cropping
- Trimming the edges of an image in editing to improve composition or change aspect ratio. It reduces the pixel count. Composition basics →
- Depth of field
- The zone in front of and behind the focus point that looks acceptably sharp. Wide apertures, long lenses and close subjects make it shallow. Focus and depth of field →
- Diffraction
- Softening that appears at very small apertures as light spreads around the aperture edges. On many cameras it becomes visible beyond roughly f/11 (approximate). Aperture and f-numbers →
- Distortion
- Bending of straight lines by a lens, either outward (barrel) or inward (pincushion). Most editors can correct it with lens profiles. Focal length, angle of view and crop factor →
- Dynamic range
- The span between the darkest and brightest tones a sensor or scene can hold with detail, usually measured in stops. Light metering and the histogram →
- ETTR (expose to the right)
- A raw shooting approach that makes the exposure as bright as possible without clipping highlights, then darkens it in editing for cleaner shadows. Light metering and the histogram →
- EXIF metadata
- Information stored inside an image file, such as camera model, settings, date and sometimes GPS location. RAW vs JPEG and dynamic range →
- Exposure
- The total amount of light that reaches the sensor for one image, set by aperture, shutter speed and ISO together. What is exposure? The exposure triangle →
- Exposure compensation
- A control that tells the camera to make its automatic exposure brighter or darker, usually in steps of 1/3 stop. Exposure modes: M, A, S and P →
- Exposure modes
- Camera settings such as Manual, Aperture priority, Shutter priority and Program that decide which values you set and which the camera chooses. Exposure modes: M, A, S and P →
- Exposure triangle
- A teaching model showing how aperture, shutter speed and ISO trade off against each other. Change one and you must adjust another to keep the same brightness. What is exposure? The exposure triangle →
- Exposure value (EV)
- A single number that stands for every aperture and shutter speed pair giving the same exposure. One EV equals one stop. What is exposure? The exposure triangle →
- F-number
- The ratio of focal length to the diameter of the aperture opening, written as f/2.8, f/8 and so on. Smaller numbers mean a wider opening. Aperture and f-numbers →
- Fisheye lens
- An ultra-wide lens that deliberately curves straight lines to capture up to about 180 degrees. Focal length, angle of view and crop factor →
- Flash
- A brief, intense burst of light from a built-in or separate unit, used to light a subject or fill shadows. Artificial light and flash →
- Flash sync speed
- The fastest shutter speed at which the whole sensor is uncovered at once, so a normal flash lights the full frame, often about 1/200 s (approximate). Artificial light and flash →
- Focal length
- The distance, in millimetres, that describes a lens's angle of view. Short focal lengths see wide; long ones magnify. Focal length, angle of view and crop factor →
- Focus peaking
- A manual focus aid that highlights the sharpest edges on screen in a bright colour.
- Focus stacking
- Combining several frames focused at different distances into one image that is sharp from front to back, common in macro work. Focus and depth of field →
- Full frame
- A sensor about 36 × 24 mm, the same size as a 35 mm film frame. Sensor sizes and crop factor →
- Global shutter
- A sensor readout that captures every pixel at the same instant, avoiding rolling shutter distortion. Shutter speed and motion →
- Golden hour
- The period shortly after sunrise and before sunset when sunlight is low, soft and warm. Golden hour and blue hour →
- Graduated ND filter
- A filter that is dark on one half and clear on the other, used to hold back a bright sky while keeping the foreground exposed. Camera filters: ND, polariser and more →
- Guide number
- A rating of flash power: guide number divided by subject distance gives the f-number needed at a stated ISO. Always check whether it is quoted in feet or metres. Artificial light and flash →
- Hard and soft light
- Hard light comes from a small or distant source and casts crisp shadows; soft light comes from a large or diffused source and wraps gently. Artificial light and flash →
- HDR (high dynamic range)
- A technique that combines differently exposed frames into one image holding detail in both deep shadows and bright highlights. Light metering and the histogram →
- HEIF / HEIC
- A newer compressed format that stores better quality than JPEG at a similar file size and supports 10-bit colour. RAW vs JPEG and dynamic range →
- High-speed sync (HSS)
- A flash mode that pulses light rapidly so you can use shutter speeds faster than sync speed, at the cost of reduced power. Artificial light and flash →
- Histogram
- A graph of how many pixels sit at each brightness level, from black on the left to white on the right. Light metering and the histogram →
- Hyperfocal distance
- The focus distance at which everything from half that distance to infinity looks acceptably sharp, a favourite trick for landscapes. Focus and depth of field →
- IBIS (in-body image stabilisation)
- A system that moves the sensor to counter camera shake, letting you hand-hold slower shutter speeds with any lens. Shutter speed and motion →
- ISO
- The sensor's brightness gain setting. Higher ISO brightens the image in dim light but adds noise. ISO and image noise →
- JPEG
- A compressed, ready-to-share image format processed in camera. Files are small but hold less editing headroom than raw. RAW vs JPEG and dynamic range →
- Kelvin (colour temperature)
- A scale for the colour of light: lower values such as 3200 K look warm and orange, higher values such as 6500 K look cool and blue. White balance and colour temperature →
- Leading lines
- Lines such as roads, rivers or fences that draw the eye through the image toward the subject. Composition basics →
- Lens flare
- Streaks, rings or haze caused by bright light bouncing inside the lens. A lens hood helps prevent it. A short history of camera lenses →
- Long exposure
- A shutter speed of roughly a second or more, used to smooth water, streak clouds or gather faint light. A tripod is usually needed. Shutter speed and motion →
- Macro lens
- A lens that focuses close enough to show small subjects at life size (1:1) or larger on the sensor. Focal length, angle of view and crop factor →
- Megapixel
- One million pixels. More megapixels allow larger prints and more cropping but do not by themselves make a better picture. Sensor sizes and crop factor →
- Metering modes
- The way the camera reads scene brightness: evaluative (matrix) across the frame, centre-weighted, or spot on a small area. Exposure modes: M, A, S and P →
- ND filter
- A neutral density filter darkens the whole scene evenly so you can use slower shutter speeds or wider apertures in bright light. Camera filters: ND, polariser and more →
- Negative space
- Empty or quiet areas around the subject that give it room and emphasis. Composition basics →
- Noise
- Random grain and colour speckles in an image, most visible in shadows and at high ISO. ISO and image noise →
- Noise reduction
- Software processing that smooths grain and colour speckles, trading off a little fine detail. ISO and image noise →
- Panning
- Following a moving subject with the camera during a slowish exposure so the subject stays fairly sharp while the background streaks. Shutter speed and motion →
- Phase-detection AF
- An autofocus method that compares light from two sides of the lens to know at once which way and how far to move focus. It is fast and good for tracking.
- Prime lens
- A lens with one fixed focal length. Primes are often smaller, sharper and brighter than zooms covering the same range. Focal length, angle of view and crop factor →
- Raw file
- Minimally processed sensor data saved by the camera, giving the most latitude for exposure and colour changes in editing. RAW vs JPEG and dynamic range →
- Rear-curtain sync
- Firing the flash at the end of the exposure so motion trails appear behind a moving subject rather than in front of it. Artificial light and flash →
- Reciprocity
- The rule that equal changes in opposite directions, such as one stop wider aperture and one stop faster shutter, keep exposure the same. What is exposure? The exposure triangle →
- Rolling shutter
- Distortion that occurs when the sensor is read line by line, making fast-moving subjects lean or wobble with an electronic shutter. Shutter speed and motion →
- Rule of thirds
- A guideline that divides the frame into a 3 × 3 grid and places key elements on the lines or their crossings. Composition basics →
- Sensor size
- The physical dimensions of the imaging chip, such as full frame, APS-C or Micro Four Thirds. It affects field of view, depth of field and noise. Sensor sizes and crop factor →
- Edit-stage processing that boosts edge contrast to make detail look crisper. Too much creates halos.
- Shutter speed
- How long the sensor is exposed to light, from thousandths of a second to many minutes. Fast speeds freeze motion; slow speeds blur it. Shutter speed and motion →
- Single vs continuous AF
- Single AF (AF-S, One-Shot) locks focus once; continuous AF (AF-C, AI Servo) keeps adjusting as the subject moves.
- sRGB
- The standard colour space for the web and most screens. It is the safest choice for images you share online. RAW vs JPEG and dynamic range →
- Stop
- A step that doubles or halves the light. Opening up one stop lets in twice as much light; closing down one stop lets in half. What is exposure? The exposure triangle →
- Street photography
- Candid photography of everyday life in public spaces, valuing timing and observation over staging. A short history of photography →
- Sweet spot
- The aperture range where a given lens is sharpest, often about two stops down from wide open (approximate). Aperture and f-numbers →
- Telephoto lens
- A long focal length lens that magnifies distant subjects and appears to compress the space between near and far objects. Focal length, angle of view and crop factor →
- TIFF
- A large, usually uncompressed or losslessly compressed format used for archiving and handing edited images to printers. RAW vs JPEG and dynamic range →
- Tilt-shift lens
- A lens that can tilt to change the plane of focus or shift to correct converging lines, used in architecture and for miniature-style effects. A short history of camera lenses →
- Tone curve
- An editing tool that remaps brightness levels along a curve, giving fine control over contrast in shadows, midtones and highlights. Light metering and the histogram →
- TTL flash
- Automatic flash metering that measures light through the lens, usually with a brief pre-flash, to set flash output. Artificial light and flash →
- UV / protective filter
- A clear filter mostly used today to protect the front lens element, since digital sensors already block most ultraviolet light. Camera filters: ND, polariser and more →
- Vignetting
- Darkening toward the corners of the frame, from lens design or added on purpose in editing. Aperture and f-numbers →
- White balance
- A setting that removes colour casts from the light source so white objects look neutral. White balance and colour temperature →
- Wide-angle lens
- A lens with a short focal length that takes in a broad view, popular for landscapes, interiors and architecture. Focal length, angle of view and crop factor →
- Zebras
- Striped overlays shown on screen over areas that are near or past clipping, common on mirrorless cameras and video gear. Light metering and the histogram →
- Zoom lens
- A lens whose focal length can be changed, for example 24–70 mm, so you can reframe without moving. Focal length, angle of view and crop factor →