Many smartphones have an automated HDR feature that relies on computational imaging techniques to capture and combine multiple exposures.

A single image captured by a camera provides a finite range of luminosity inherent to the medium, whether it is a digital sensor or film.

The human eye, through non-linear response, adaptation of the iris, and other methods, adjusts constantly to a broad range of luminance present in the environment.

[11] High-dynamic-range photographs are generally composites of multiple standard dynamic range images, often captured using exposure bracketing.

Afterwards, photo manipulation software merges the input files into a single HDR image, which is then also tone mapped in accordance with the limitations of the planned output or display.

[update][12] The exposure value (EV) refers to the amount of light applied to the light-sensitive detector, whether film or digital sensor such as a CCD.

Photographers have developed calculation methods and techniques to partially overcome these problems, but the use of a sturdy tripod is advised to minimize framing differences between exposures.

Tonal information and details from shadow areas can be recovered from images that are deliberately overexposed (i.e., with positive EV compared to the correct scene exposure), while similar tonal information from highlight areas can be recovered from images that are deliberately underexposed (negative EV).

Information stored in high-dynamic-range images typically corresponds to the physical values of luminance or radiance that can be observed in the real world.

For that purpose, they do not use integer values to represent the single color channels (e.g., 0–255 in an 8 bit per pixel interval for red, green and blue) but instead use a floating point representation.

[21] Nikon's approach is called 'Active D-Lighting' which applies exposure compensation and tone mapping to the image as it comes from the sensor, with the emphasis being on creating a realistic effect.

Unlike traditional HDR, Levoy's implementation of HDR+ uses multiple images underexposed by using a short shutter speed, which are then aligned and averaged by pixel, improving dynamic range and reducing noise.

[24] Some of the sensors on modern phones and cameras may combine two images on-chip so that a wider dynamic range without in-pixel compression is directly available to the user for display or processing.

[25] This can be done via multiple methods: Some cameras designed for use in security applications can automatically provide two or more images for each frame, with changing exposure.

This is usually termed a wide dynamic range (WDR) function[31] Examples include CarCam Tiny, Prestige DVR-390, and DVR-478.

[32] The idea of using several exposures to adequately reproduce a too-extreme range of luminance was pioneered as early as the 1850s by Gustave Le Gray to render seascapes showing both the sky and the sea.

[33] Manual tone mapping was accomplished by dodging and burning – selectively increasing or decreasing the exposure of regions of the photograph to yield better tonality reproduction.

[citation needed] Color film capable of directly recording high-dynamic-range images was developed by Charles Wyckoff and EG&G "in the course of a contract with the Department of the Air Force".

The concept of neighborhood tone mapping was applied to video cameras in 1988 by a group from the Technion in Israel, led by Oliver Hilsenrath and Yehoshua Y. Zeevi.

Global HDR was first introduced in 1993[3] resulting in a mathematical theory of differently exposed pictures of the same subject matter that was published in 1995 by Steve Mann and Rosalind Picard.

[4] On October 28, 1998, Ben Sarao created one of the first nighttime HDR+G (high dynamic range + graphic) image of STS-95 on the launch pad at NASA's Kennedy Space Center.

Steve Mann developed and patented the global-HDR method for producing digital images having extended dynamic range at the MIT Media Lab.

[53][54] RED EPIC-X can capture time-sequential HDRx images[17] with a user-selectable 1–3 stops of additional highlight latitude in the "x" channel.

The Arri Alexa camera uses a dual-gain architecture to generate an HDR image from two exposures captured at the same time.

[27] With the advent of low-cost consumer digital cameras, many amateurs began posting tone-mapped HDR time-lapse videos on the Internet, essentially a sequence of still photographs in quick succession.