Читать книгу Collins Complete Photography Manual - Collins Dictionaries - Страница 65

Scanner makers may also quote ‘dynamic range’ or ‘DMAX’figures for scanners designed specifically for photographers. The dynamic range figure refers to the range of brightnesses that the scanner can record. Film can have a very high brightness range indeed, so a large dynamic range (‘DMAX’) is an advantage. Avery good flatbed scanner is unlikely to have a DMAX value higherthan 4.0 while afilm scanner might have a DMAX value of 4.2 or more. The small difference in figures makes a big difference to how successfully the scanner can capture detail in deep shadow and bright highlight areas of your slides and negatives.

High resolutions are useful only when scanning film directly. Here, you need a resolution of 2700dpi or more to capture all the detail in the photograph. However, even though many flatbed scanners offer higher resolutions than this, their optical and mechanical components prove the limiting factor, not the resolution. You can usually expect to get sharper pictures from afilm scanner than from a flatbed scanner with a transparency adaptor, whatever the quoted resolution figures.