Perceived Brightness Effect

amtrak · Oct 16, 2003

Several comments I've received lately lead me to believe
that a 1/2 acrylic ball lens creates a higher "perceived brightness" than a reflector does.

Namely,
when I turn on LED_ASAP's Arc AAA to pay my bar bill
(1/2 acrylic ball 1/4 in. lens)
people at all angles are TAKEN ABACK by how bright it is.

Subsequent testing staring into the LED (not with my good eye)
leads me to agree with the comments I've received.

Sonic · Oct 17, 2003

I have a CMG Ultra that is fitted with a 3/4" acrylic ball and holder and it does greatly increase output. But it does this at the cost of all side-spill light. In mine, the ball lens almost triples output, but in a much smaller spot of light.

iddibhai · Oct 17, 2003

i think it has to do with the area of luminance; smaller areas appear brighter whereas larger ones less so, with the same lamp behind it. that's what i think anyway /ubbthreads/images/graemlins/smile.gif

phyhsuts · Oct 17, 2003

Sonic - No relation to the CMG I trust? /ubbthreads/images/graemlins/smile.gif
The lenses do NOT increase light output. They just concentrate them into a smaller solid angle (higher intensity or candle power) Thus a brighter but smaller spot at the same distance.

JSWrightOC · Oct 17, 2003

I tried a 1/2 acrylic ball in front of a Luxeon with an NX-05 optic...the result was a projected spot and ring much like what you would see if you directly observed the glow of the emitter through the optic. Needless to say, I preferred the raw output of the optic. /ubbthreads/images/graemlins/smile.gif

I am guessing there would be a difference in the focused beam pattern depending on the distance between the 1/2 ball and the light source?

amtrak · Oct 17, 2003

I did a little further testing (i.e. staring into the LED):
- Arc AAA with 1/4 in. 1/2 ball lens was painful,
- Micro Illuminator seemed slightly less painful unless the angle was perfect, and
- Ill Pill in Legend AA with full acrylic ball lens was quite painful.

As silly as the results sound,
the reason I'm interested is because it relates to the fun factor of having a light (i.e. the number of people that say "Ow, turn it off!").

And I'm thinking that a lens somehow provides a more "saturating" (smooth/even?) beam perception-wise than a reflector does. Oh well - no more testing for me.

cmendoza · Oct 17, 2003

I have a MM+R2. When I put the 3/4" spere in the minimag bezel it shoot a small square of light incredibly far! Lights the tops of the trees across the street! Quite fun but hardly any side spill.