In this first workshop, I want talk about the basic knowledge, demands and give definitions for the terms of HDR-photography. What content-related and technical pre-requisites are necessary for the successful start in HDR-photography and what do the terms, which are mentioned in this process, mean?

Since more then three years, increasingly often, I have encountered photographs which display an almost unnatural depth of field, extreme contrasts or even appear surrealistic. In the most instances, it is a so-called High-Dynamic-Range-Image. Viewers, who see these images, for the first time, are often astounded and the first question pops into their mind, "How does this work?"

A new form of photography:
HDR-photographs are images, which are technically not possible, in the terms of the classical photography. Suddenly, there are drafts in which illumination and depths, leading to a detail of contrasts, appear almost unnatural in the conventional viewing sense. The affluence of details is so extraordinary that some photographs resemble paintings, if the photorealistic effect were not present. In short, with the emergence of the HDR-photography, the scope of digital photography and image processing has been enriched and enhanced. This fascinating form of image processing, which was often belittled by professionals as a technical fad, has found its way into the print and online media.

Expanding the range of contrast:
Often a spectacular motive such as the interior of a sun-filled nave, turns out to be less than spectacular, afterwards. What appeared as a top motive, on location, is a disappointment when viewed on the monitor, at home. This is the case because neither the camera nor the monitor can even come close to matching the ability of the human eye in its range of contrasts. A sunny day easily reaches differences in light intensity of 1 000 000: 1. The human eyes can easily register - without adaptation - a range of contrasts of 10 000: 1. A normal commercial quality camera lens merely reaches a range of contrasts of 1 000: 1. For example, if a camera and a monitor could display the range of contrasts of a summer scene, the viewer would have to wear sunglasses. In other words, one could not be able to discern a monitor from a window.

Surmounting the limits of the camera technique:
With the help of the HDR-photography and the HDR-processing, the range of contrasts of photography artificially approaches that of the human eye. This is done through the compilation of many different exposures. Normally, the exposure is set to the main motive. Either the optimal exposure is made, whereas the depth of details fades into the  black or the focus is on the depth, whereas the lights blend into a white surface. Through the photographs at different exposures, the scope of the entire range of contrasts is captured, then being transformed, with the help of the HDR-software such as Photomatix Pro, to one image. Thus a 32-Bit image, which is the actual high dynamic range image, is created and then transformed within the technique of tone mappings to a 16- or 8-Bit image, the low dynamic range image.

The equipment:
Besides the camera equipment and accessories such as tripod and remote release, one also needs a specialized software for the HDR-processing. A market leader with good standing is the company HDRsoft with its software package Photomatix. In addition, a good graphics editing program for pre- and post-processing, is necessary. It is common knowledge that professional graphics editing programs, foremost Adobe Photoshop, have a great need for resources. In addition with HDR-imaging, one works almost exclusively with 16- and 32-bit databases. Also, the automatic processing of raw data in batch modus requires high processor performance. Next to the high processor- and graphics performance requirements upon the computer, the storage capacity of the hard disk drive(s) is essential. In the framework of HDR-imaging, numerous photographs, generated HDR-images and tone mapped images are produced. Often copies of the tone mapped images with various settings and moods are stored. If one retains the 16-bit database, in order to reduce the loss of quality in the post-processing, then the file size can easily reach or exceed 50 MB for a single image.

If one wants to create panoramas, the needs are even greater. Provided that the HDR-images in the optimal quality are available, the panorama can reach a size of more than 1000 MB. Of course, there is the possibility of producing reduced and compressed copies before further processing of the panorama. However, who wants to make compromises in terms of quality after the extensive preliminary work?