High Dynamic Range Imaging (HDRI)
|Recently there have been some interesting developments in the area of high dynamic range imaging. Most conventional digital cameras save images in a 24-bit format such as BMP, TIFF or JPG. These formats use 8 bits (256 levels) per RGB primary color to represent the full spectrum present in the image. While 24-bit color is often sufficient for common computer graphics and print work this limited range of levels can lead to some problems with photography. Often a 24 bit range is not sufficient to capture all of the highlight or shadow detail present in a scene. Often when retouching a scene this limited tonal range can produce undesirable artifacts such as color banding. The Panoscan MK-3 can capture up to 14 bits per color. (16,384 levels per RGB primary color.) These files can be saved as a 48-bit TIFF format file which has far greater latitude for retouching and color correction.
New high dynamic range monitors such as the DR37-P by Brightside Technologies have come onto the market. Such monitors are capable of displaying MK-3 images with breathtaking quality. These monitos also allow easier editing and retouching of Panoscan HDR images.
In some instances even 48 bit range is not enough to capture a whole scene. For example a dark room interior with sunlight streaming through an open window may blow out completely. In these cases there are some new approaches to capturing this full range. This technique is called High Dynamic Range Imaging. (HDRI) This HDRI can take several forms and be captured in several ways.
The most immediate and practical use for HDRI for most panoramic photographers is to reduce the contrast in a scene to allow detail present in the bright areas of a scene to be shown while preserving all of the shadow detail in the scene. (For example dark wood paneling in a room is shown in detail while the scene outside the window looks natural.) To accomplish this goal the full range of the scene is captured in one or more bracketed exposures and then these exposures are combined to produce a natural image. This high dynamic range information is combined and the tonal range is reduced using a means of tonal mapping. Simple contrast reduction results in a flat washed out looking image that is not desirable. New techniques such as gradient tonal mapping produces a much more desirable result. Since the Panoscan MK-3 system produces standard 24 or 48-bit TIFF files these images can be used with several off the shelf applications like PhotoMatix to produce extraordinary results. Click here to see an example of how PhotoMatix can be used with an MK-3 image. Another very useful method involves contrast blending from multiple exposures. Erik Krause's method of blending multiple exposures offers maximum flexibility and control of the resulting image.
Another use for HDR images is to actually capture the full dynamic range of a scene for scientific or industrial uses. The motion picture industry has been using HDRI for producing computer generated special effects. Lighting from a location or set can be captured in 2 or 3 bracketed exposures and then combined into a single HDR file that can be used to light synthetic models added to the scene. Because the Panoscan MK-3 produces standard TIFF images they can be used with off the shelf applications such as HDR shop to produce HDR images. Click here to learn more about HDR shop.
Several film companies have already used Panoscan cameras for capturing HDRI in films such as The Incredible Hulk, Terminator 3 and The Time Machine. To learn more about the HDRI capability of the Panoscan MK-3 camera please contact us to set up a demonstration.