The atmospere, character and message of an image are quintessentially influenced by the distribution of black and white areas in the tonal values. In classic photography the specific subject-related use of illumination is described as high-key and low-key photography.
In high-key images bright, finely distinguished highlight tones dominate with an essentially soft illumination.
High-key image with the corresponding histogram.
Low-key images, however, consist predominantly of dark tones and harsher light is used, which provides a three-dimensional feel that is rich in contrast and shadow detail.
Low-key image with the corresponding histogram.
The zone system – a concept established by Ansel Adam
The term "Zone Matching" is derived from the "zone system", which is an exposure processing concept developed by the doyen of black-and-white photography, Ansel Adams.
The concept aims at rendering the best possible tonal values, taking into account the whole gamut that encompasses shooting, development and the final enlargement of the negative onto photo paper, since all those aspects are interrelated.
The subject´s brightness values are subdivided into the so-called zones and the exposure values of the relevant image parts are established by means of a hand-held meter.
Taking the enlarged image with the desired tonal values as a basis the photographer can ensure that the tonal values of the paper print (which can only reproduce a specific contrast range) exactly meet his requirements by a well-directed increasing or reducing of the contrast when developing the negative.
Broadening the dynamic range of digital cameras.
The zone system is originally from the perfected art of film photography and the individually exposed and developed negatives which are basically intended for large format prints. The basic problem of managing the subject´s high contrast and at the same time reproducing the relevant image parts finely graduated with a differentiated tonal range is still not solved. Even highly evolved CCD sensors feature only a limited dynamic range. Tonal values which are not separated on shooting cannot be reproduced by laborious post processing either. That´s why Konica Minolta added a technology to its digital cameras that is based on the method of the classic zone system that is dedicated to capture picture relevant subject sections with an optimal tonal range: zone matching. It helps to obtain a precise tonal reproduction in difficult photographic situations such as high-key and low-key scenes.
High-key and low-key – a speciality of the Dynax 5D and Dynax 7D
The zone matching mode that both the Dynax 5D and Dynax 7D feature selectively adjusts the tonal curve to the respective high-key and low-key situation and provides an emphasis on the corresponding tonal areas without loss of detail or noise, thanks to an selectively extended dynamic range.
Depending on the subject, high-key mode or low-key mode can be chosen.
Setting the zone matching mode
a.) Dynax 7D
In order to activate the zone matching mode the ISO button is set to "zone matching" in the custom menu. After that you can simply select either high-key or low-key mode via pressing the ISO button.
b.) Dynax 5D
Zone matching can be carried out directly from the ISO menu.
High-key mode provides fine highlight detail on images that consist of mainly bright areas. Exposure, sensitivity and gradation are adjusted in the best possible way so that the hightlights do not bleach out as would be quite common with the standard setting. Wedding pictures depicting the bride dressed in bright white illustrate a prime example of a high-key scene.
Without/With high-key mode: the highlight detail demonstrates the difference (Left without and right with low-key)
Details high-key mode
With the high-key mode an ISO sensitivity of 250 (Dynax 7D) or 200 (Dyanx 5D) is employed and the image is less exposed.
This ensures that the analogous signals of the CCD sensors regarding the highlights are not given too much weighting, as this would otherwise preclude their delivering any useful information. The tonal curve is selectively raised in order to obtain the optimal brightness values in the highlights and in addition all tonal values are maintained.
A low-key scene depicting predominantly dark tones and colours is improved by the low-key mode which achieves a balanced shadow detail without noise emerging in the dark shades. This is accomplished by selectively decreasing the gradation combined with giving a slightly increased basic exposure.
Without/With high-key mode: the highlight detail demonstrates the difference
Details low-key mode
With the low-key mode an ISO sensitivity of 100 (Dynax 7D) or 80 (Dynax 5D) is employed and the image is exposed to a greater extent. This ensures that the analogous signals of the CCD sensors concerning the shadows provide sufficient information.
Then the gradation curve is decreased so that the brightness values meet the optimum in the shadows and additionally all tonal values are maintained.
The low ISO setting ensures moreover an almost free of noise reproduction of the dark tonal values which the low-key image predominantly consists of.
Conclusion – Zone matching provides enhanced creative flexibility
Left without and right with high-key.
With zone matching the Dynax 7D and Dynax 5D digital SLR cameras offer an ingenious auto exposure and gradation setting that delivers an optimal reproduction of the tonal values in the highlight and shadow detail captured in high-key and low-key images.
This has the benefit of giving even more freedom to literally picture ones´s ideas.
* This content is taken from the konicaminoltaphotoworld.com website that was unfortunately taken offline. I take full responsibility for offering this here on dyxum but I honestly believe that this contests SHOULD be available to all Konica Minolta customers; this is the least they can do !