HDR Photography Glossary & Technical Dictionary

A camera feature that automatically captures a sequence of photos (typically 3, 5, or 7 frames) at varying exposure values (e.g. -2, 0, +2 EV) with a single press of the shutter button.

An algorithmic process that identifies and removes blur or semi-transparent double-images caused by moving objects (such as swaying tree branches, pedestrians, or vehicles) across bracketed exposures.

A spatial tone mapping algorithm developed by Michael Ashikhmin that models human visual adaptation, specifically focusing on preserving specular highlights and local luminance contrast.

The specialized technique of combining short exposures (to prevent starry core burnout and foreground light bleed) with long tracking exposures (to resolve faint nebulae and milky way details).

Automating the alignment, merging, and tone mapping of dozens or hundreds of bracket sets without requiring manual intervention for every single photo.

An edge-preserving, noise-reducing smoothing filter used in computational imaging and tone mapping that averages nearby pixels based on both spatial distance and radiometric radiometric difference.

The number of bits used to represent the color and luminosity of each pixel. Standard camera RAW files capture 12 or 14 bits of integer precision per channel, whereas merged HDR radiance maps use 32-bit floating point precision.

The continuous rate at which a digital camera clears raw bracket bursts from its internal RAM cache onto the SD or CFexpress memory card (measured in MB/s).

When sensor pixel wells saturate completely at maximum brightness (blown white highlights) or register zero light below the noise floor (pure black shadows), resulting in irrecoverable detail loss.

The full range of colors that a specific color space or display monitor is capable of reproducing. Standard web sRGB covers ~35% of visible colors, DCI-P3 covers ~45%, and Rec. 2020 covers over 75%.

An optical optical imperfection where a lens fails to focus all wavelengths of light to the same convergence point, creating magenta and green edge fringes along high-contrast boundaries.

An RGB color space developed by the Digital Cinema System Specification that features a significantly wider green and red spectrum than standard sRGB.

An adaptive logarithmic tone mapping operator developed by Frédéric Drago that compresses high-luminance areas while maintaining natural perceptual contrast in midtones.

Capturing automated exposure brackets from an unmanned aerial vehicle (UAV) to balance bright sky horizons against dark ground landscapes.

The ratio between the maximum detectable light intensity (brightest highlight without clipping) and the minimum detectable intensity (deepest shadow above sensor noise floor), measured in Exposure Value (EV) or stops.

A logarithmic base-2 scale representing combinations of shutter speed, aperture, and ISO that result in an equivalent exposure level. Changing exposure by +1 EV doubles the amount of light reaching the sensor.

A blending technique that bypasses creating an intermediate 32-bit floating point radiance map, instead combining the best-exposed pixel regions from multiple RAW frames using multiresolution Laplacian pyramid decomposition.

An open-source high dynamic range raster image format developed by Industrial Light & Magic that natively supports 16-bit and 32-bit floating point precision per color channel with lossless compression.

A local tone mapping operator created by Raanan Fattal that compresses dynamic range by attenuating large gradient magnitudes while amplifying fine local details.

A real estate interior photography workflow that captures a natural ambient bracketed shot combined with a handheld off-camera flash shot to achieve perfect window views and accurate interior color fidelity.

Semi-transparent or displaced copies of moving subjects that appear when multiple bracketed frames taken at different times are combined into a single composite.

Unnatural glowing outlines or dark fringes that appear along high-contrast boundaries (such as where dark mountains or building rooftops meet a bright sky).

An open consumer high dynamic range standard using the Rec. 2020 wide color gamut, 10-bit color depth, and the Perceptual Quantizer (SMPTE ST 2084) electro-optical transfer function with static metadata.

An open-source command-line tool (`align_image_stack`) utilizing control points and rigid transformation matrices to sub-pixel align handheld bracketed photos before merging.

A widely used open-source C/C++ software library for extracting raw sensor data from digital cameras (supporting CR2, CR3, NEF, ARW, DNG, RAF, RW2).

An encoding format developed by Greg Ward that compresses wide dynamic range radiance data into a standard TIFF container using logarithmic luminance and perceptual chromaticity.

The premier open-source GUI application for HDR imaging and tone mapping, originally released in 2006 under the name Qtpfsgui by Giuseppe Rota, built on the Qt framework and licensed under GPLv2.

A pair of psychophysical tone mapping algorithms developed by Rafal Mantiuk that compress dynamic range by modeling human contrast sensitivity functions (CSF) across spatial frequencies.

The seminal 2007 algorithm that introduced exposure fusion based on three perceptual quality weights: well-exposedness, local contrast, and color saturation.

A standardized unit of visible light intensity emitted by a display screen (one nit equals one candela per square meter). Standard office displays emit 250-350 nits; true HDR displays deliver 1000 to 1400 nits peak.

The unwanted increase in visible grain and chrominance blotches when deep shadow zones are boosted during tone mapping.

One of the earliest commercial standalone HDR software suites, developed by HDRsoft, famous for its Details Enhancer tone mapping algorithm and robust batch processing.

An electro-optical transfer function (EOTF) engineered to match human contrast perception from 0.0001 up to 10,000 nits, replacing legacy gamma curves in HDR workflows.

A calibrated two-dimensional floating-point dataset representing the physical light values (radiance) of the original scene prior to display compression.

A tone mapping methodology developed by Erik Reinhard inspired by the photographic Zone System, featuring both a global logarithmic operator and a local dodge-and-burn operator.

Simulating high dynamic range by exporting multiple exposure variations (-2, 0, +2 EV) from a single 14-bit RAW file and blending them back together.

A mathematical algorithm designed to compress high dynamic range radiance data into a lower dynamic range medium (such as a standard 8-bit sRGB monitor or print) while preserving perceptual contrast.

Maintaining absolute physical camera immobility across multi-second bracket sequences to prevent angular micro-misalignments between exposures.

A specialized real estate interior workflow where a fast, underexposed bracket is masked specifically over bright window panes to retain exterior landscaping details while keeping interior lighting warm and natural.