Light quality question: Brightness vs clarity?

Malherbi

Newly Enlightened
Joined
Dec 5, 2012
Messages
8
Hi folks,
Just confused about something.........I have two torches of almost equal power (claimed, and I have also checked with a lux meter at the same distance, etc....). The spread of the light is about the same, the colour of the light is about the same, and the middle point of the light and also the spill around it is about the same.

However, the clarity in which I am able to see things in detail and even read signs etc, is VERY different. In fact, I can see less clearly with the slightly more powerful torch (only about 20 lumens more----so can't be because I am blinded by it !). OK, there is a huge price difference in the two torches). One is Petzl which costs a bomb, and the other is a cheapo brandless XYZ thing from the big online site, but has the same output, shape, spill, colour, etc.
I have also done 'blind tastings' using my friends, and they have always said that one is clearer than the other without knowing which light source is which.

Am I missing something ? Can someone explain the difference in clarity?

Thanks !
 

enomosiki

Flashlight Enthusiast
Joined
Mar 13, 2011
Messages
1,109
The "cheapo brandless" light probably has its output overrated.

Whereas Petzl uses the ANSI/FL-1 standard to measure the output (meaning the out-the-front lumens after 30 second to 3 minutes of running), the cheapo probably uses estimated emitter measurement.
 

JCD

Enlightened
Joined
Apr 12, 2010
Messages
892
One variable you did not mention is CRI. I'm not sure if that would cause the effect you are seeing, though.

Personally, I've mostly switched back to incans. Despite the fact they are (mostly) brighter, I can't see as well with my LED based lights. Increased clarity is actually a good way to describe the improvement. Beside being brighter, most of my LEDs are also cooler than my incans. Also, the incans have a higher CRI value than any of my LEDs. (Again, I can't be sure that is what causes the difference; I just know there is a difference.)

Anyway, I'll be watching this thread in hopes that someone can provide some insight.
 

inetdog

Enlightened
Joined
Mar 4, 2013
Messages
442
Also, the incans have a higher CRI value than any of my LEDs. (Again, I can't be sure that is what causes the difference; I just know there is a difference.)

Anyway, I'll be watching this thread in hopes that someone can provide some insight.

By definition, the CRI of an incandescent that does not tint the glass will be 100, once you correct for whatever color temperature it is operating at. It (actually a black body radiator) is the standard against which CRI figures are calculated. Since there is so much variation among different dyes which we perceive in incan or sunlight as the same color, any light that has spectral lines in its output will have a CRI lower than 100. (The low pressure sodium light, with only two very closely spaced spectral lines is so bad that it has a negative CRI.)
Your degree of comfort with a low CRI illuminant will vary depending on what sort of colored objects and backgrounds you are working with and your "perfect color" sensitivity, similar to good or perfect pitch in hearing.
 
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