[argyllcms] Re: Feature request (and an implied question)

  • From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 26 Jul 2010 20:28:57 -0700

On 2010 Jul 26, at 5:16 PM, Matthieu DUBAIL wrote:

> I'm pretty sure that the problem with EV or Guide Number calculation here 
> (apart from proper calibration constant) is that you need to know the 
> distance of the light source.

Um -- I probably could have been more specific.

I'm not looking for an absolute measurement of a light source, but for a 
measurement of the light levels reaching the measuring device. Think of 
Argyll's option to check ambient lighting conditions versus measuring the 
brightness of a display.

Both the light meter and the spectrophotometer have ambient metering modes; I'm 
just looking to compare the two. (And, in experiments yesterday and today, I've 
already had a lot of success. Adjusting the incident / ambient mode readings 
also ``by-the-way'' brought those in line with the spot / reflective readings, 
which also matched a camera's built-in meter. And it was only a quarter-stop of 
adjustment needed, reasonably consistent across a wide range of light values, 
so I'm pretty confident that it's a not-insane thing to do.)



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