Add new comment

Numbers and diagrams are

Numbers and diagrams are results of experimenting, and even contain a certain experimental error of about 0.5%..1% (see for example how 18% grey translates into L=49.5 instead of being exact L=50). The text is also based on our experience in coding raw converters. All the conclusions you can easily verify in direct experiments - a camera with a spotmeter, a grey card or a sheet of white paper that does not contain optical brightner, a source of light like a flashgun, a wide dynamic range scene like a landscape in a sunny day, and Rawnalyze software is all that is needed.

Centred exposure is an exposure that places the subject into one of three zones that result in most detailed print. In other words, it is the exposure that is centred on the proper exposure of the subject rather on the preserving extreme highlights. You may want to read the complimentary article Spot-Metering: Reading Adams in Reverse Direction for the suggestions on exposure compensation.

Iliah Borg