Glossary
Achromatic Lens
Two-element (or more) design that converges red and blue light at the same point, reducing basic color fringing.
—Adobe RGB
Wide-gamut RGB color space about one-third larger than sRGB, favored for high-end printing.
—Anamorphic Lens
Optic that horizontally “squeezes” a wide scene onto the sensor; later de-squeezed for cinematic widescreen, oval bokeh, and horizontal flares.
—Anti-Aliasing (Low-Pass) Filter
Slight blur filter placed over a sensor to suppress moiré and false-color artifacts.
—Aperture
Adjustable opening in a lens; controls light quantity and depth-of-field, expressed as an f-number (e.g., f/2.8).
—Aperture Priority (A / Av)
Exposure mode where you choose the aperture and the camera sets the shutter speed.
—Apochromatic Lens
Corrects three (sometimes four) wavelengths, virtually eliminating chromatic aberration.
—APS-C Sensor
≈ 22 × 15 mm chip with roughly 1.5–1.6 × crop relative to 35 mm full-frame.
—Aspect Ratio
Frame width-to-height proportion (3:2, 4:3, 16:9, etc.).
—Aspherical Lens
Uses non-spherical surfaces to curb distortion and coma while keeping lenses more compact.
—Auto-Exposure Bracketing (AEB)
Automated series of brighter/darker frames around the metered exposure.
—Autofocus (AF)
Camera system that drives the lens to the distance of maximum focus contrast or phase alignment.
—AVIF
Modern, high-efficiency still-image format based on the AV1 codec; supports HDR and 10-bit color.
—Backlighting
Major light source positioned behind the subject, creating rims, halos, or silhouettes.
—Barrel Distortion
Straight lines bow outward near frame edges, common in wide-angle lenses.
—Bayer Filter
Red-green-blue mosaic atop most sensors; demosaiced to create full-color pixels.
—Beauty Dish
Shallow parabolic reflector producing crisp yet flattering light for portraits.
—Bit Depth
Bits per color channel (8-bit = 256 levels); greater depth yields smoother tonal gradations.
—Bloom
Highlight glow or bleed caused by lens/sensor scatter—often emulated for a dreamy look.
—Bokeh
Aesthetic quality of out-of-focus areas; judged by blur smoothness and highlight shape.
—Bracketing
Shooting a sequence that varies one parameter (exposure, focus, white balance) for safety or composites.
—Burst Mode (Continuous Shooting)
Rapid sequence of frames per second while the shutter button is held.
—Bulb Mode
Shutter stays open as long as the release is held, enabling very long exposures.
CCD Sensor
Charge-Coupled Device; superb image quality but slower readout than CMOS.
—Center-Weighted Metering
Exposure algorithm that emphasizes the central area of the frame.
—Chromatic Aberration
Lens inability to focus all colors at the same point, seen as color fringes.
—Circle of Confusion (CoC)
Largest blur spot that still registers as a point; core of depth-of-field math.
—CMOS Sensor
Complementary-MOS chip; fast, low-power, dominant in modern still/video cameras.
—Color Space
Defined gamut and math that map numeric values to visible colors (e.g., sRGB, ProPhoto).
—Color Temperature
Hue of light expressed in Kelvin—lower = warmer (≈ 3200 K), higher = cooler (≈ 5600 K).
—Composition
Deliberate arrangement of elements within the frame to guide the viewer’s eye.
—Continuous Autofocus (AF-C)
Focus continuously adjusts while the shutter button is half-pressed; vital for tracking motion.
—Crop Factor
Ratio of a sensor’s diagonal to full-frame; affects angle-of-view equivalence.
—Depth of Field (DoF)
Zone that appears acceptably sharp; governed by aperture, focal length, distance, and sensor size.
—Diffraction
Softening from light bending around very small apertures; limits extreme f-stops.
—Dodging and Burning
Selectively lightening (dodge) or darkening (burn) areas to shape tonal balance.
—Double Exposure
Two exposures combined in one frame for creative overlay effects.
—DSLR (Digital Single-Lens Reflex)
Interchangeable-lens camera with mirror and optical viewfinder.
Evaluative / Matrix Metering
Multi-zone metering that uses scene-recognition algorithms for balanced exposure.
—EXIF
Metadata block stored in image files (camera, lens, ISO, date, GPS, etc.).
—Exposure
Total light reaching the sensor—a balance of aperture, shutter speed, and ISO.
—Exposure Compensation
Manual ± EV override of the meter’s suggested exposure.
—Film Photography
Recording images on light-sensitive emulsion, developed chemically.
—Fisheye
Ultra-wide lens (~ 180° diagonal) with heavy, intentional distortion.
—Focal Length
Distance (mm) from lens’s optical center to sensor at infinity focus; sets angle of view.
—Focus
Adjusting the lens so light converges sharply at the sensor plane.
—Focus Peaking
Live-view overlay highlighting high-contrast edges that are in focus.
—Focus Stacking
Merging multiple focus-shifted shots to extend depth-of-field.
—Forced Perspective
Visual trick making near objects look huge or distant ones tiny by clever placement.
—Front / Rear Curtain Sync
Flash fires at shutter open (front) or just before it closes (rear) for different motion trails.
—F-Stop
Numeric aperture value; each full stop halves or doubles transmitted light.
—Full-Frame Sensor
36 × 24 mm sensor matching 35 mm film dimensions.
Golden Ratio
1 : 1.618 proportion used for visually pleasing compositions.
—Grain
Random silver-halide clusters in film; digital equivalent is noise.
—Halation
Film glow where bright areas bleed due to light scattering in the emulsion; often simulated digitally.
—Halide
(1) Light-sensitive silver-halide crystals.
(2) Popular pro camera app for iOS.
—HEIC
High-Efficiency Image Container using HEVC compression; Apple’s default still format since 2017.
—High Dynamic Range (HDR)
Capturing or combining exposures to preserve extreme shadow and highlight detail.
—High-Key Photography
Bright, low-contrast style with minimal shadow.
—Histogram
Graph showing tonal distribution—shadows left, highlights right.
—Hot Shoe
Standard camera mount with electrical contacts for flash and accessories.
IBIS (In-Body Image Stabilization)
Sensor shifts to counter camera shake.
—Image Stabilization (IS)
Any optical, sensor-shift, or electronic system that reduces blur from camera movement.
—Infrared Photography
Images captured in light just beyond visible red using IR filters or converted cameras.
—IPTC
Standard metadata fields for captions, credits, rights, and keywords.
—ISO
Sensitivity index; doubling ISO doubles sensor gain and halves required light.
—JPEG
Common 8-bit lossy compressed image format based on DCT.
Leading Lines
Compositional elements (roads, rails) that guide the viewer toward the subject.
—Lens Flare
Stray reflections causing streaks or haze—creative or distracting.
—Light Meter
Device (built-in or handheld) that measures scene luminance for exposure settings.
—Low-Key Photography
Dark, shadow-rich style emphasizing dramatic contrast.
M – N
Macro Lens
Lens designed for 1 : 1 (life-size) reproduction or greater, with flat-field sharpness.
—Manual Mode (M)
Photographer sets both shutter speed and aperture (and usually ISO) manually.
—Medium Format
Imaging area larger than 35 mm (e.g., 44 × 33 mm digital or 120 roll film).
—Megapixel
One million pixels; higher counts allow larger or crisper prints given equal sensor quality.
—Metering
Camera’s method of measuring light to determine exposure.
—Micro Four Thirds
Mirrorless format with 17.3 × 13 mm sensor (2 × crop); small bodies and lenses.
—Mirrorless Camera
Interchangeable-lens camera without reflex mirror; uses electronic viewfinder or LCD.
—Motion Blur
Streaking of moving subjects during exposure.
—Negative Space
Intentional empty areas that emphasize the subject.
—Neutral Density (ND) Filter
Gray filter uniformly cutting light, enabling long exposures or wide apertures in bright conditions.
—Noise
Random luminance or color speckles, more pronounced at high ISO or in shadows.
Optical Viewfinder (OVF)
Real-time optical composing window in DSLRs and rangefinders.
—Overexposure
Excess light causing highlights to clip to pure white.
—P3 (Display P3)
Wide-gamut RGB space (≈ DCI-P3) used by many modern screens.
—Panorama
Ultra-wide field-of-view image created by stitching frames or using a swing-lens.
—Pixel Shift
Multi-shot method moving the sensor slightly to boost resolution and color fidelity.
—Polarizing Filter
Transmits a single light plane; cuts reflections, deepens skies, boosts saturation.
—Prime Lens
Fixed focal length lens, typically smaller, faster, and sharper than zooms at equivalent apertures.
—ProPhoto RGB
Extremely wide-gamut color space; risk of clipping on standard displays.
—ProRAW
Apple RAW container combining sensor data and computational-photography metadata.
RAW Format
Unprocessed, high-bit-depth sensor data with maximal editing latitude.
—Red Eye
Red pupils in flash photos when light reflects off the retina.
—Reflector
Neutral or colored surface that bounces fill light onto a subject.
—Rolling Shutter
Skew or “jello” artifacts from line-by-line sensor readout during rapid motion.
—Rule of Thirds
Divides frame into a 3 × 3 grid; key elements placed on lines or intersections.
Sensor
Silicon array that converts photons into electrical charge.
—Shutter Priority (S / Tv)
You set shutter speed; camera selects aperture.
—Shutter Speed
Time the shutter stays open; controls motion blur and exposure.
—Single Autofocus (AF-S / One-Shot)
Locks focus once when the shutter is half-pressed; best for static subjects.
—Softbox
Fabric-diffused enclosure for strobes/LEDs that yields broad, soft light.
—Spot Metering
Exposure based on a small (≈ 1–5 %) area of the frame.
—sRGB
Default color space for the web and consumer devices.
—Stacked Sensor
Pixel layer bonded atop circuitry layer for ultra-fast readout and higher dynamic range.
—Strobe
High-power studio flash head with short duration and fast recycle times.
—Telephoto Lens
Long focal length producing narrow angle of view and subject magnification.
—Tethering
Shooting with the camera linked to a computer/tablet for real-time review and control.
—Through-The-Lens (TTL) Metering
Camera measures light after it passes through the lens; also governs flash output.
—TIFF
Flexible image container often used uncompressed or in lossless compression; supports high bit depth.
—Tilt-Shift Lens
Offers tilt (changes focus plane) and shift (corrects perspective) movements.
—Time-lapse
Series captured at intervals, played back at normal frame rate to compress time.
Zebra Stripes
Live-view overlay showing over- or under-exposed areas with animated stripes.
—Zenith Photography
Camera aimed straight up, common in astrophotography or architectural studies.
—Zone Focusing
Pre-setting focus using a depth-of-field scale so any subject within that “zone” is acceptably sharp.
—Zone System
Ansel Adams’ 10-step framework matching scene tones to controlled exposure and development zones.
—Zoom Ratio
Longest focal length divided by shortest in a zoom lens (e.g., 24–105 mm ≈ 4.4 ×).