Lux Incident Meter
While using a gray card is an excellent way to obtain light readings, there is a way to obtain a light level measurement with a little more precision. Inexpensive digital lux meters (see figure 17-1) are available that measure the total amount of incident light and return an absolute numerical reading in units known as lux. A lux unit is a measurement of the amount of light striking the incident meter.
Lux meters are fairly cheap (about the price of an inexpensive microwave) and yet very accurate. These meters, used by farmers and gardeners, are employed to determine the amount of light striking a particular area ...