-------- Original-Nachricht -------- > Datum: Sat, 24 Jul 2010 12:10:04 -0700 > Von: Ben Goren <ben@xxxxxxxxxxxxxxxx> > An: argyllcms@xxxxxxxxxxxxx > Betreff: [argyllcms] Feature request (and an implied question) > spotread -a -v already shows ambient light levels in lux. Would it be > possible to also show light levels in EV units? > > The conversion (for ISO 100) is: > > EV = log2(lux / 2.5) > lux = 2.5 * 2**EV > > The implied question, of course, is, ``Does it make sense to calibrate a > lightmeter by making it match the measurements made by Argyll with an i1 Pro > in ambient mode?'' I can't imagine why not, but... One issue to consider is that readings from different light meters are only comparable if they have the same directional characteristics. I think the i1 has a light measurement head with a cosine response, while many light meters intended for photographic purpuses have different directional characteristics (e.g. hemispherical), see also http://en.wikipedia.org/wiki/Light_meter Regards, Gerhard -- GMX DSL: Internet-, Telefon- und Handy-Flat ab 19,99 EUR/mtl. Bis zu 150 EUR Startguthaben inklusive! http://portal.gmx.net/de/go/dsl