feet, then when the flash was moved to 8 feet from your subject (double the
distance), the flash meter would measure f/4.0, or^1 / 4 of the light output from
the original f/8.
The 90 Percent Rule.
If there is one lighting principal that every glamour photographer should
know, especially every digital glamour photographer, it’s what I call the 90
percent rule. Simply stated, the 90 percent rule says that what is pure black will
absorb 90 percent of the light that hits it, while what is pure white will reflect
90 percent of the light that hits it. You must also remember that there is still
another 10 percent that is either ab sorbed or reflected, depending on whether
your reflective source is pure white or pure black. The key word here is “pure”;
most whites and blacks are not pure.
METERING AND EXPOSURE 107