Dette er allerede sagt så enkelt og greitt som det kan få blitt over hos luminous-landscape, så jeg tillater meg å kopiere inn teksten derfra:

«Let’s assume for the purposes of illustration that a digital SLR has a dynamic range of 5 stops (it’s usually closer to 6 stops, but let’s not quibble). When working in raw mode, which you should be, most cameras record a 12 bit image.

A 12 bit image is capable of recording 4,096 (2^12) discrete tonal values. One would think that therefore each F/Stop of the 5 stop range would be able to record some 850 (4096 / 5) of these steps. But, alas, this is not the case. The way that it really works is that the first (brightest) stop’s worth of data contains 2048 of these steps — fully half of those available.

This realization carries with it a number of important lessons, the most important of them being that if you do not use the right-hand fifth of the histogram for recording some of your image you are in fact wasting fully half of the available encoding levels of your camera. (<- les dette avsnittet tre ganger, så du er sikker på at det sitter!)

But, we all know (or at least should by now) that the worst sin in digital imaging is to blow out the highlights — just as it was when shooting slide film. Once they’re blown (past the right-hand edge of the histogram) it’s bye-bye data.»