A 
BJohn Wattie, www.kiwizone.org
The range between light and dark is limited in photography.
The solution is to take several pictures ranging from over-exposed (which show shadow detail) to under-exposed (revealing bright details). Then combine them to display the full dynamic range. This is especially useful if the pictures are to be printed, because prints have a much lower dynamic range than transparencies or computer monitors.
HDR is High Dynamic Range, achieved in a computer. HDR means photographs can now have a similar contrast range to human eyes.
St Mary's Church in Tikitiki has bright stained glass windows and superb Maori carving in dark Totara wood.
Image A shows the best a digital camera can do with one exposure while
image B is a combination of three exposures.
A B
The image below is a roll-over image. Run your mouse over it and the standard picture will change to an HDR image. This allows detailed comparison of the two techniques, but at low resolution. The original images are 4 times bigger than this (16 times the number of pixels) and reveal exquisite detail in the carving, simultaneously with display of the stained glass.
Not only is the dynamic range improved by HDR, but the colours are much closer to the original rich tones of this lovely church.
St Mary's Church, Tikitiki: stained glass versus dark wood carving
Urewera National Park: dense, dark forest versus bright clouds.
Puketi Forest Day after a big storm, panorama HDR of a crashed tree.
How to make HDR images (not the method used by the author!)
