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JohnK said:
As an optometrist that has done industrial work, I don't really understand the value of the Lux meters (with flash lights). They measure a brightness value at a "point", which says absolutely nothing about the "surround", or "lumens", or really anything.
I could forsee a manufacturer making a reflector that pops a zillion "lux" at a tiny point, then goes to heck every where else.
I think the only scenerio where this measurement is useful, is in real world situations with DIFFUSE lighting; where perhaps an assembly line is fairly uniformly lighted by fluroscents, etc., and judgements can be made as to the proper brightness/illumination level.
With tightly focused lights, I find the measurements almost useless; viv a vis a LUX reading for the SL TL-2 LED at far higher readings than the TL-3 LED, or the SF L4. I like the TL-2 LED, and TL-3 LED, I own them both, but feel that these reading are at best misleading (Quickbeam, whom I respect a great deal, is the first to explain this, when he gives the readings), and at worst, totally misrepresent what we are trying to find out.
"Lux" measurements give you nothing except the often noted example of a Laser brightness at ONE POINT, and absolutely NOTHING else.
NO other information, zip, nada !
Gotta be a better way.
I suppose reviewers astute comments, added to the "Lux" stuff will have to make the difference.
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John,
That's exactly why I use indirect "total output" measurements and rate lights only in relation to each other, rather than to a specific standard. I have several methods of indirect measurement and find that though they may give different absolute figures, the proportional relationship between lights stays almost exactly the same, within 1%-2%, so I feel comfortable that my readings tell me what I need to know as far as total output is concerned.
I also agree that an astute eyeball description can be as useful, or sometimes even more useful than a "number".
Brightnorm