Tonemapping

A technique used by HDR software to ‘map’ the extremely wide brightness range of a high dynamic range image into an editable form where the extremes of shadow and highlight detail are preserved. It’s usually the first and sometimes the only step in making an HDR image.

Shadow and highlight recovery

Feature on some cameras and in some image-editing programs that lets you recover very bright or dark areas of the picture which would otherwise be lost to over- or under-exposure. It uses the extra image data captured in RAW files, so you have to shoot RAW to be able to do this later on a computer.

Radiance

An adjustment in some HDR programs that has a somewhat vague and undefined effect, in a technical sense. In Aurora HDR, for example, it adds a kind of soft ‘glow’ which goes well with the supersaturated, other-wordly feel of most HDR images.

Merge (HDR)

HDR (high dynamic range) images are usually created by blending a series of different exposures of the same scene to capture a wider brightness range than the camere could capture with a single exposure. These are then blended together by HDR software using a ‘merge’ process.

HDR (high dynamic range)

HDR stands for high dynamic range photography. It combines a series of frames taken at different exposures to capture a much wider dynamic (brightness) range than the camera could capture with a single exposure. These exposures are merged using HDR software.

Glow effect

This has two possible meanings. One is a soft-focus ‘glow’ used to enhance portraits, for example. The other is an undesirable side-effect of HDR or localised contrast techniques, where the software attempts to blend one area of adjustment with another but creates a soft ‘glow’ effect around objects as a result.

Ghosting (HDR)

When you merge a series of different exposures to create a single HDR image, you sometimes get movement between the frames from leaves blowign in the breeze, waves, pedestrians and moving vehicles, and these can cause ‘ghosting’ in the merged image. Most HDR software has a ‘ghost removal’ option which slows down the merging process but can reduce or remove this ghosting.

Bracketing

Taking the same shot at a series of different exposures with the intention of choosing the best one later or merging them together to create an HDR image. Most cameras offer an auto exposure bracketing option. You choose the bracketing interval (the difference between the exposures, typically 1EV) and the number of frames (usually 3, sometimes 5 or even 7). Some cameras offer other types of bracketing, e.g. white balance bracketing or even focus bracketing.