Out of curiosity, I have just completed a comparison test in which I roughly quantified the total useful light output of several high-end LED and HID flashlights.
The methodology:
1. A Nikon D300 digital SLR was mounted on a tripod pointed at a wall in a dark room with a white ceiling
2. The camera was set to aperture-preference mode so that the shutter-speed readout would be the only parameter varying with the illumination
3. Each light in turn was turned on and aimed at the ceiling directly above the camera and held at a distance that put the whole of the secondary beam pattern on the ceiling. The only light not falling directly on the ceiling was the third-order spillover, which does not contribute significantly to the useful beam pattern and does not contain much light flux in any case
4. The shutter speed (i.e., exposure time) was read from the camera meter for each light
The effect of reading the light intensity off a wall illuminated by diffusely reflected light from the beam falling on the ceiling is to sample the integrated total illumination produced by the flashlight, eliminating the variations due to the different beam-intensity profiles--the beam contour and the beam width. Linearity of response by the meter is assumed, consistent with the linear response of the camera's detector operating in an ordinary range of light values.
The results:
(Meter readings are reciprocal seconds, e.g., 100 indicates 1/100 of a second, so that the values are in direct proportion to the total light output.)
Light (nominal power): Nominal Lumens/Meter Reading
Microfire Warrior III (35 W HID): 3500/100
Microfire Warrior II (24 W HID): 1800/40
Microfire Challenger 500 (12 W total LED x 7) (full power): 700/40
Microfire Terminator II (12 W HID): 500/20
Microfire Challenger 500 (<1 W total? LED x 7) (low power): 100/2.5
SureFire Lumamax L7 (5 W LED x 1): 100/5
SureFire Lumamax L4 (5 W LED x 1): 100/4
The conspicuous outlier here (in a positive sense) is the Challenger L500R at full power, producing 40% of the light of the Warrior III, whereas Microfire's own figures would have it producing only 20%. The low-power setting, on the other hand, is consistent with the claims for it and the W-III: about 2.5% of the W-III (claims work out to 3%) but not consistent with the claims for the same light at its low power and high power settings (6% measured vs. 14% per claims). Since SureFire prides itself on its objective and rational integrating measurements of its lights' outputs, and since the two SF lights give mutually pretty consistent results, I am inclined to use them as calibrators, giving a ratio of approximately 1 (arbitrary) unit per 20 lumens.
The Challenger at full power gives results slightly (15%) higher than consistent with this, and the Terminator II slightly (20%) lower. The Challenger at low power and both Warriors are substantially lower, around 50% of claimed in all instances.
This gives the fan of HID, like me, pause. The Challenger is equal or superior in all respects to the Warrior II: similar price and light output, shorter and lighter package, better color and beam uniformity, instant-on, no restriction on rapid cycling, low-power working option, and (surprisingly to me, as I thought that HID bulbs were more efficient than LEDs), doing it all at half the battery drain and therefore twice the runtime with the same battery (12 vs. 24 W and 100 vs. 50 min per mfr). And undoubtedly more shock-resistant. Look for my W-II on eBay!
--howard
The methodology:
1. A Nikon D300 digital SLR was mounted on a tripod pointed at a wall in a dark room with a white ceiling
2. The camera was set to aperture-preference mode so that the shutter-speed readout would be the only parameter varying with the illumination
3. Each light in turn was turned on and aimed at the ceiling directly above the camera and held at a distance that put the whole of the secondary beam pattern on the ceiling. The only light not falling directly on the ceiling was the third-order spillover, which does not contribute significantly to the useful beam pattern and does not contain much light flux in any case
4. The shutter speed (i.e., exposure time) was read from the camera meter for each light
The effect of reading the light intensity off a wall illuminated by diffusely reflected light from the beam falling on the ceiling is to sample the integrated total illumination produced by the flashlight, eliminating the variations due to the different beam-intensity profiles--the beam contour and the beam width. Linearity of response by the meter is assumed, consistent with the linear response of the camera's detector operating in an ordinary range of light values.
The results:
(Meter readings are reciprocal seconds, e.g., 100 indicates 1/100 of a second, so that the values are in direct proportion to the total light output.)
Light (nominal power): Nominal Lumens/Meter Reading
Microfire Warrior III (35 W HID): 3500/100
Microfire Warrior II (24 W HID): 1800/40
Microfire Challenger 500 (12 W total LED x 7) (full power): 700/40
Microfire Terminator II (12 W HID): 500/20
Microfire Challenger 500 (<1 W total? LED x 7) (low power): 100/2.5
SureFire Lumamax L7 (5 W LED x 1): 100/5
SureFire Lumamax L4 (5 W LED x 1): 100/4
The conspicuous outlier here (in a positive sense) is the Challenger L500R at full power, producing 40% of the light of the Warrior III, whereas Microfire's own figures would have it producing only 20%. The low-power setting, on the other hand, is consistent with the claims for it and the W-III: about 2.5% of the W-III (claims work out to 3%) but not consistent with the claims for the same light at its low power and high power settings (6% measured vs. 14% per claims). Since SureFire prides itself on its objective and rational integrating measurements of its lights' outputs, and since the two SF lights give mutually pretty consistent results, I am inclined to use them as calibrators, giving a ratio of approximately 1 (arbitrary) unit per 20 lumens.
The Challenger at full power gives results slightly (15%) higher than consistent with this, and the Terminator II slightly (20%) lower. The Challenger at low power and both Warriors are substantially lower, around 50% of claimed in all instances.
This gives the fan of HID, like me, pause. The Challenger is equal or superior in all respects to the Warrior II: similar price and light output, shorter and lighter package, better color and beam uniformity, instant-on, no restriction on rapid cycling, low-power working option, and (surprisingly to me, as I thought that HID bulbs were more efficient than LEDs), doing it all at half the battery drain and therefore twice the runtime with the same battery (12 vs. 24 W and 100 vs. 50 min per mfr). And undoubtedly more shock-resistant. Look for my W-II on eBay!
--howard
