Archive for August, 2014

This is going to be a quick one. First of all, no matter what other meters one might own, the basic illuminance meter, with its readout in Lux or Fc remains an essential. You pull it out, press a button, get a number. The issue is with the latest generation of LED fixtures and retrofit lamps. They present a somewhat skewed spectral balance that can cause issues with older meters. For example, my trusty old (very very old) Minolta Color Meter II shows all LED sources as being roughly 200 CCT cooler than they actually are, sometimes, sometimes not. My other old trusty bag filler is a Minolta T-1H, which is great under daylight and tungsten sources, but not so good under LEDs, where  readings are off about 12% most of the time, and when exposed to LEDs with any flicker in them – the meter has a hard time finding a reading to settle on. I also have a Testo 540 digital ligth meter, which is an excellent in-the-pocket device, as it is very slim and includes a cover for the light sensor. At a cost of under $140, they are hard to beat for a simple tag-along meter for general illuminance measurement. (more…)


Light meters are an essential tool for anyone involved in the lighting profession. The human eye lies to us with its unique capacity to invisibly correct for brightness variations, while the brain fills in missing pieces and compensates for color variations. For professionals, it is important to see through this biological variability to understand what we are actually looking at. One might ask why, if observers are compensating so readily, is it necessary to have objective understanding? These are the five reasons I feel having sufficient light metering is a critical tool for lighting professionals: (more…)