In Reply to: OT: light meter for HT use? posted by Aroc on April 27, 2004 at 03:58:27:
Photo meters used for measuring light for photographic exposures read out in exposure values (EV numbers), and not direct light units of measure. They are used to measure incident and reflected light.Both a foot-candle and a foot-Lambert are equal to 1 lumen per square foot. The foot-candle measures light that is incident on a surface while a foot-lambert is a measurement of light being radiated from a source. The problem with measuring a foot-Lambert is that the light reading sensor needs to be directly on the surface so that the reading is not affected by light fall off (1/d^2) where "d" is the distance from the source to the meter.
If you could find a Photo Research Lite Mate, or Sekonic L-246 (much cheaper) foot-candle meter you could read the ambient light (foot-candles), and, in theory, approximate a foot-Lambert reading by holding the meter cell without the integrating lumidisc against the CRT screen in the area you want to read.
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Follow Ups
- Re: OT: light meter for HT use? - Dooby 06:49:32 04/28/04 (4)
- Re: a few questions ... - Aroc 08:11:41 04/28/04 (3)
- Re: a few answers - Dooby dooby do 14:15:32 04/29/04 (2)
- What you need - Dooby Dooby Dooby Do 06:01:37 04/30/04 (1)
- Re: thanks for all your help - Aroc 10:21:34 04/30/04 (0)