self portrait

[Bart_In_A_Kilt]

high dynamic range imaging (HDRI or just HDR) is a set of techniques that allows a greater dynamic range of luminances between light and dark areas of a scene than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.

High dynamic range imaging was originally developed in the 1930s and 1940s by Charles Wyckoff. Wyckoff's detailed pictures of nuclear explosions appeared on the cover of Life magazine in the mid 1940s. The process of tone mapping together with bracketed exposures of normal digital images, giving the end result a high, often exaggerated dynamic range, was first reported in 1993,[1] and resulted in a mathematical theory of differently exposed pictures of the same subject matter that was published in 1995 by Steve Mann and Rosalind Picard.[2] In 1997 this technique of combining several differently exposed images to produce a single HDR image was presented to the computer graphics community by Paul Debevec.

This method was developed to produce a high dynamic range image from a set of photographs taken with a range of exposures. With the rising popularity of digital cameras and easy-to-use desktop software, the term HDR is now popularly used[3] to refer to this process. This composite technique is different from (and may be of lesser or greater quality than) the production of an image from a single exposure of a sensor that has a native high dynamic range. Tone mapping is also used to display HDR images on devices with a low native dynamic range, such as a computer screen.

The idea of using several exposures to fix 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. Such rendering was impossible at the time using standard techniques, the luminosity range being too extreme. Le Gray used one negative for the sky, and another one with a longer exposure for the sea, and combined the two in a single picture in positive.[4]

The desirability of HDR has been recognised for decades but its wider usage was, until quite recently, precluded by the limitations imposed by the available computer processing power. Probably the first practical application of HDRI was by the movie industry in late 1980s and, in 1985, Gregory Ward created the Radiance RGBE image file format which was the first (and still the most commonly used) High Dynamic Range Imaging file format. Steve Mann developed the method for producing digital images having extended dynamic range at the MIT Media Laboratory and filed a patent on the technique in May of 1996. US patent 5,828,793 was issued in October 1998 for this work. 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 HDRI.[citation needed]

HDRI is commonly used in the real estate and architectural photography markets[5] due to its advantage of properly exposing both window and room areas simultaneously.

Until recently there were no "pure" examples of HDR based cinematography, since the effects were most commonly used during composited sequences in films. However with the advent of low cost consumer digital cameras, many amateurs began posting HDR timelapse videos on the Internet. 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.

[Highlander31]

Nice photo. Unlike Rex, I don't photograph well (no matter who takes the photo.)

[Macman]

high dynamic range imaging (HDRI or just HDR) is a set of techniques . . .

Thanks for the explanation, BIAT. I had no idea what HDR was, only that I liked the photo Chad did. Is this something I can do with my little-ole' digital camera?

[Kiltman]

high dynamic range imaging (HDRI or just HDR) is a set of techniques that allows a greater dynamic range of luminances between light and dark areas of a scene than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.

High dynamic range imaging was originally developed in the 1930s and 1940s by Charles Wyckoff. Wyckoff's detailed pictures of nuclear explosions appeared on the cover of Life magazine in the mid 1940s. The process of tone mapping together with bracketed exposures of normal digital images, giving the end result a high, often exaggerated dynamic range, was first reported in 1993,[1] and resulted in a mathematical theory of differently exposed pictures of the same subject matter that was published in 1995 by Steve Mann and Rosalind Picard.[2] In 1997 this technique of combining several differently exposed images to produce a single HDR image was presented to the computer graphics community by Paul Debevec.

This method was developed to produce a high dynamic range image from a set of photographs taken with a range of exposures. With the rising popularity of digital cameras and easy-to-use desktop software, the term HDR is now popularly used[3] to refer to this process. This composite technique is different from (and may be of lesser or greater quality than) the production of an image from a single exposure of a sensor that has a native high dynamic range. Tone mapping is also used to display HDR images on devices with a low native dynamic range, such as a computer screen.

The idea of using several exposures to fix 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. Such rendering was impossible at the time using standard techniques, the luminosity range being too extreme. Le Gray used one negative for the sky, and another one with a longer exposure for the sea, and combined the two in a single picture in positive.[4]

The desirability of HDR has been recognised for decades but its wider usage was, until quite recently, precluded by the limitations imposed by the available computer processing power. Probably the first practical application of HDRI was by the movie industry in late 1980s and, in 1985, Gregory Ward created the Radiance RGBE image file format which was the first (and still the most commonly used) High Dynamic Range Imaging file format. Steve Mann developed the method for producing digital images having extended dynamic range at the MIT Media Laboratory and filed a patent on the technique in May of 1996. US patent 5,828,793 was issued in October 1998 for this work. 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 HDRI.[citation needed]

HDRI is commonly used in the real estate and architectural photography markets[5] due to its advantage of properly exposing both window and room areas simultaneously.

Until recently there were no "pure" examples of HDR based cinematography, since the effects were most commonly used during composited sequences in films. However with the advent of low cost consumer digital cameras, many amateurs began posting HDR timelapse videos on the Internet. 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.

Thanks for the information. At this point HDR seems to be a fad, but soon it may takes its rightful place.