Amprobe lm 120 light meter auto ranging amprobe lm 120 the amprobe lm 120 light meter measures the visible light from fluorescent metal halide high pressure sodium or incandescent sources it is a portable easy to use digital light meter designed for simple one hand operation reading in lumen lux or foot candle fc units br br br the lm 120 measures a wide range of light up to 20 000 fc or 200 000 lux with an accurate high resolution of 0 01 fc lux this unit is autoranging plus