HDR photography... what is it?

Greg

Make RME Rockcrawling Again!
Admin
Since there seems to be some confusion on what 'HDR' really is... so how about we define HDR and have a discussion about it?

High Dynamic Range imaging.

From Wikipedia-

http://en.wikipedia.org/wiki/High_dynamic_range_imaging

In image processing, computer graphics, and photography, high dynamic range imaging (HDRI or just HDR) is a set of techniques that allow a greater dynamic range of luminances between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. This wider dynamic range allows HDR images to more accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight.

The two main sources of HDR imagery are computer renderings and merging of multiple photographs, the latter of which in turn are individually referred to as low dynamic range (LDR) or standard dynamic range (SDR) photographs.

Tone mapping techniques, which reduce overall contrast to facilitate display of HDR images on devices with lower dynamic range, can be applied to produce images with preserved or exaggerated local contrast for artistic effect.

In photography, dynamic range is measured in EV differences (known as stops) between the brightest and darkest parts of the image that show detail. An increase of one EV or one stop is a doubling of the amount of light.

High-dynamic-range photographs are generally achieved by capturing multiple standard photographs, often using exposure bracketing, and then merging them into an HDR image. Digital photographs are often encoded in a camera's raw image format, because 8 bit JPEG encoding doesn't offer enough values to allow fine transitions (and also introduces undesirable effects due to the lossy compression).

Any camera that allows manual over- or under-exposure of a photo can be used to create HDR images.

Some cameras have an auto exposure bracketing (AEB) feature with a far greater dynamic range than others, from the 3 EV of the Canon EOS 40D, to the 18 EV of the Canon EOS-1D Mark II.

The Pentax K-7 DSLR has an HDR mode which captures an HDR image and then outputs (only) a tone-mapped JPEG file.
 

cjfj80

Active Member
Location
Midway
It's pretty neat actually if it is applied correctly. Most Camera's will Auto Bracket only 3 shots (one f/stop each way of normal exposure). I found that taking at least 5-6 shots (2-3 each stop of normal exposure) works much better. Photoshop or an HDR converter is a must. CS5 Has a great feature that will put together something like 15-20 shots. A tripod is also very handy because you need to get the picture the exact same every time.
 
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