Sony HDR-XR520VE | Sony HDR-XR520VE HD Camcorder

High Dynamic Range images usually correspond to the physical values of luminance or radiance that can be seen in the real world. This differs from the normal digital images, which represent colors that should appear on a monitor. HDR image formats are often called "scene-referred" as opposed to traditional digital images, which are "device-referred" or "output-referred". Traditional imagery is often encoded for the human visual system which is usually called "gamma encoding" or "gamma correction". HDR images are often linear meaning they represent relative values of radiance or luminance.

A higher number of bits per colour channel are required with HDR images than traditional images because of the linear encoding and that they need to represent values from 10−4 to 108 or more. The 16-bit or 32-bit floating point numbers are often used to represent HDR pixels yet when the appropriate transfer function is used, HDR pixels for some applications can be represented with as few as 10–12 bits for luminance and 8 bits for chrominance without introducing any visible quantization artifacts

HDR has been recognized for years but until quite recently its wider usage was precluded by the limitations imposed by the computer processing power. The first practical application of HDR was by the film industry in late 1980s and, in 1985, Gregory Ward created the Radiance RGBE image file format which was the first High Dynamic Range file format. The first to introduce the concept of digital HDR camera, that takes images at different exposures and combining them to a single image was a group from the Technion in Israel led by Prof. Y.Y.Zeevi who filed the first patent of this concept in 1988.

In 1993 the first commercial medical camera was introduced that performed real time capturing of multiple images with different exposures, and producing an HDR video image. Steve Mann developed and patented the method for producing digital images having extended dynamic range at the MIT Media Laboratory. In 1997 the technique of combining several differently exposed images to produce a single HDR image was presented to the public by Paul Debevec and his research has since contributed significantly to the popularization of HDR.

Since the effects were most commonly used during composited sequences in films there were no "pure" examples of HDR cinematography. But with the low cost consumer Digital Camcorder amateurs began posting HDR videos on the web. In 2008 Mobius/Quark Films released "Silicon Valley Timelapse" which is said to feature almost 1.1 million frames of tone mapped HDR, making it the largest single source of tone mapped HDR footage available to date. HDR is commonly used in the real estate and architectural photography markets due to its advantage of properly exposing both window and room areas simultaneously.

For the ultimate in HDR Digital Camcorders check out the stunning Sony HDR-XR520VE.