Aberration
Coloured fringes that appear most often along high-contrast edges because different wavelengths are refracted differently by the optical system. Lens design, aperture choice and careful processing can all reduce the…
A — Z
Glossary
Acutance
A measure of perceived sharpness produced by contrast along detail edges. It can be increased in processing, but excessive correction creates halos and an unnatural digital texture.
Ambient adaptation
The process by which vision adjusts to the level and colour of illumination. It makes different light sources appear neutral to us even when the camera records clear differences in…
Analog photography
Photography made on light-sensitive film rather than a digital sensor. The image character depends on the emulsion, exposure, development and the later scan or darkroom print.
Aperture
The adjustable opening in a lens that controls the amount of light. It also affects depth of field, diffraction and the rendering of out-of-focus points of light.
Aperture priority
A mode in which the photographer chooses the aperture while the camera selects shutter speed according to the measured light and ISO. It gives quick control over depth of field…
Art photography
A practice in which viewpoint, subject choice, editing and presentation form a recognisable authorial statement. The photographer does more than record reality: they deliberately build a visual language and take…
Asymmetry
An arrangement in which elements on opposite sides of the frame are not mirrored yet can remain balanced through scale, tone, direction or meaning. Asymmetry often gives a photograph tension,…
Autofocus
A system that sets focus automatically using phase detection, contrast detection or a combination of both. Performance depends on light, scene contrast, subject movement and the selected focus area and…
Available light
Light already present in the photographed situation, without lamps added by the photographer. It may come from the sun, a window, the street or interior lighting and often preserves the…
Backlight
Light coming from behind the subject. It can separate a silhouette, reveal translucent material or reduce visible detail, so exposure and flare require deliberate control.
Bokeh
The way a lens renders out-of-focus areas. Its character depends on optical design, aperture, distance and background; it is not simply another name for shallow depth of field.
Chromatic aberration
Colour fringing around high-contrast edges caused when different wavelengths do not focus at the same point. Optical design, aperture and correction determine how visible it becomes.
Colour temperature
A description of light colour expressed in kelvins. Lower values are associated with warmer light and higher values with cooler light; white balance interprets this quality in the image.
Composition
The organisation of lines, planes, directions, visual weight, colour and empty space. Rules are a starting point, not an automatic recipe for a successful photograph.
Contrast
A difference between tones, colours, textures or meanings. Contrast can guide the eye, create drama, separate planes and reinforce the subject.
Decisive moment
The instant when form, gesture and meaning meet within one frame. It depends not only on reflexes but also on observation, anticipation and understanding of the scene.
Depth of field
The range of distances perceived as sharp. It depends on aperture, focal length, camera-to-subject distance, sensor size and the chosen standard of acceptable sharpness.
Diffraction
The bending of light at a small aperture opening, gradually reducing fine detail. The smallest f-number opening therefore does not always produce the greatest useful sharpness.
Dynamic range
The span from the darkest to the brightest tones a camera can record with useful detail. It determines how much information can be retained in high-contrast light.
Environmental portrait
A portrait that presents a person in a place connected with their life, role or work. The surroundings provide information and become part of the subject’s characterisation.
Exposure
The combined result of aperture, shutter speed and ISO. A successful exposure need not be neutral: deliberate brightness or darkness can shape the image’s mood.
Exposure equivalence
Different combinations of shutter speed, aperture and ISO can produce similar brightness but not the same image. Each choice also changes motion, depth of field, noise and optical character.
Flash synchronisation
The timing of a flash discharge in relation to the shutter. Exceeding the normal sync speed may require HSS, which changes flash character, reach and efficiency.
Focal length
A lens property that affects angle of view and the rendering of space. Perspective is determined primarily by camera position rather than focal length alone.
Framing
The fragment of reality selected within the image boundaries. Framing determines what is shown as well as the relationships, tension and information left outside the photograph.
Grain
The visible structure of photosensitive material or its digital interpretation. Grain character depends on film, exposure, development, enlargement and scanning, and can carry atmosphere rather than merely technical imperfection.
Guide number
A value describing flash power under specified conditions. It helps estimate the relationship between distance, aperture and exposure, although modifiers and bounced light alter the result.
High key
An image built predominantly from bright tones with limited deep black. High key is not accidental overexposure; it requires control of detail, contrast and visual attention.
Histogram
A graph showing the distribution of brightness in an image. It helps reveal lost detail in shadows or highlights, but does not replace an aesthetic decision or analysis of the…
Hyperfocal distance
The focus distance that provides acceptable sharpness from roughly half that distance to infinity for a chosen focal length and aperture. It is especially useful in street and landscape work.
Image sensor
The light-sensitive component of a digital camera that converts light into a signal. Size, design, resolution and readout influence dynamic range, noise, colour and the rendering of movement.
Intervalometer
A device or camera function that triggers frames at programmed intervals. It is used for time-lapse work, long sequences and recording processes that unfold over time.
ISO
A setting describing sensor signal amplification or film sensitivity. Higher ISO helps in low light, but usually increases noise and reduces dynamic range.
JPEG
A widely supported image format using lossy compression and rendered colour. It is compact and practical, but repeated saving can reduce quality and it offers less editing latitude than RAW.
Key light
The principal light that establishes the subject’s form and direction. Other sources are understood in relation to it, even when the key is an existing window or the sun.
Leading lines
Lines, edges or repeated directions that guide the viewer through a frame. Their value depends on where they lead and what relationship they create, not merely on being obvious.
Metadata
Information stored with a file, including capture settings, dates, authorship, rights and descriptions. Accurate metadata supports archiving, licensing, retrieval and responsible publication.
Narrative layer
Meaning created through relationships between people, place, gesture and image sequence. A narrative may exist within one frame or develop across an entire series.
Negative
A film image in which tones or colours are reversed, forming the source for a print or scan. Density, development and the film base influence how the final image can…
Optical viewfinder
A finder that shows the scene through an optical path rather than an electronic display. Depending on the camera, it may look through the taking lens or through a separate…
Perspective
The representation of spatial relationships produced by the camera’s position relative to the scene. Changing the viewpoint alters proportions, depth and meaning.
Photographic print
A physical photographic image made on paper or another photosensitive or printed surface. Scale, material, finish, contrast and exhibition light are part of the work, not merely packaging for a…
Picture plane
A spatial layer such as foreground, main plane or background. Building distinct planes creates depth and can connect several events within one frame.
Polarising filter
A filter that restricts selected directions of light vibration. It can reduce reflections and deepen tones, but its effect depends on the angle to the light and may be uneven…
Quadtone
A monochrome reproduction method using four inks or tonal separations. It allows nuanced control of neutrality, black depth and tonal transitions beyond a single black channel.
RAW
A format that stores sensor data with minimal processing. It offers more flexibility for exposure, colour and white-balance correction than a finished JPEG file.
Resolution
The amount of spatial detail a system can record or reproduce. Pixel count alone is incomplete; optics, focus, processing, display size and viewing distance also determine visible detail.
Rule of thirds
A common guide that divides the frame into nine fields and suggests positions for emphasis. It can organise an image but does not replace analysis of weight, movement, emptiness and…
Sensitivity
The response of film or a sensor setting to light. Greater sensitivity supports low-light work but affects grain or noise, tonal range and colour rendering.
Shutter speed
The period during which light reaches the sensor or film. A short exposure freezes movement, while a long one records motion as blur and requires control of camera shake.
Tonal gradation
The smoothness of transitions between brightness and colour values. Strong gradation retains subtle differences in skin, sky and shadow without banding or blocked tones.
Ultra-short exposure
A very brief exposure used to freeze fast motion or work in intense light. Its effectiveness also depends on movement direction, distance, focal length and the duration of any flash.
Viewpoint
The camera’s position and height relative to the scene. Viewpoint, more than focal length alone, determines relative scale, overlap between planes and emotional distance from the subject.
Vignette
A reduction of brightness near the frame edges, caused by optics or added deliberately in processing. Used carefully it can contain attention; used automatically it may become a visible mannerism.
Vignetting
A gradual darkening toward the corners, caused optically, mechanically or in processing. It can concentrate attention, but should arise from the image rather than an automatic stylistic habit.
White balance
The setting that defines neutral colour under a given light source. It may correct a colour cast faithfully or preserve it deliberately as part of the photograph’s atmosphere.
X-sync
The normal timing relationship between an electronic flash and the shutter. The fastest usable speed depends on shutter design; beyond it, a conventional flash may not illuminate the whole frame.
Yellow filter
A filter used in black-and-white photography to alter how colours translate into tone. It commonly darkens blue skies slightly and changes the separation of skin, foliage and nearby hues.
Zone system
A method relating exposure, development and final print tones. It helps the photographer previsualise where important values should fall and how the negative or file should be handled.