L2 vs L4 run time

Any theories on how the L2 can be so much brighter in total light output, but the run times are very similar?

I was under the impression that the L2's runtime on high was shorter than that of the L4. Also, the output isn't that different.

Al

i thought reviews here said L2 is getting only about 50 min on high

I don't know the official claims for runtime or brightness.
According to Flashlight Reviews:
L2
"Battery Life (advertised) ... ~1 hr. high, ~18 hrs. low"
"Overall Output ... high ~ 8900 (89.00 Comparison Chart equivalent)"

L4
"Battery Life (advertised) ... 1 hour regulated, diminishing thereafter"
"Overall Output ... ~ 5800 (58.00 Comparison Chart equivalent)"

The "~" approximately claim could very well be 50 minutes, but the 10 minute (16%) decrease in run time still doesn't seem to account for the 70% increase in brightness measurements.

There is probably a reason why it's a longer flashlight -- more advanced electronics, and it is driven harder..

You have to take into account the test he runs - he shines the light into a milkbox, and gets the overall output that way.. which means that, depending on the intensity of the hotspot, the output'll vary significantly.

The L2 and L4's reflectors are different, to begin with - the L2's reflector looks deeper than the L4's, at least in the shots I've seen on the net, which would mean that it would have a tighter and more intense hotspot. The L4's more shallow ~20mm reflector would provide the proverbial 'wall of light' but it means that the hotspot is not as intense as it might otherwise be.

According to Craig's review of the L2 at the LED Museum, it takes about 50 minutes to get to 50% brightness on the L2 on high, and 12.5 hours to 50% brightness on low. The main thing with the L2 is that the head is 'dumb', which is why the body is longer - all the electronics are there, including the regulator for the low level.

You need to take into account beam characteristics when comparing 'output'. The L5 and L6, for example, have really TIGHT hotspots compared to the L4, which mean they're better for longer distances than the L4 is - the brighter hotspot means you can actually illuminate something with an L5 or L6 at range that the L4's dimmer hotspot would not show.

A carefully performed "ceiling bounce" test will give you surprisingly accurate *comparative* total output (as opposed to "brightness") information. I verified this in one of my early reviews when I compared perceived total output of ten different lights with metered readings. I only missed one which metered almost identically to another light.

Brightnorm