Converting candela<>lux? (renamed from D10 vs. Cateye EL300)

So....
I made a bet with a friend of mine. He saw my new D10, and he thought that his Cateye EL300 bikelight put out more light. Unfortunately, I meant total lumens, while he meant hotspot brightness. Or at least he said that he meant hotspot brightness after I gave him some figures on the D10

Problem is, I don't see him for a while, so no direct comparison can be made in the next few weeks.

The EL300 seems to have a pretty focused beam, while the D10 is rather floody with a small hotspot. I found some references that hotspot brightness is around 400-540 candela. Found no figures in candela for the D10, only in lux.
1600-1800lux with NiMh, 2600-2800 lux with 14500 (they're on their way from DX...)

Is there any way to convert lux in candela, or at least to take an educated guess at which one has a brighter hotspot?

By the way, here's a thread on the EL300:
https://www.candlepowerforums.com/threads/111456
4xAA, 5 LEDs in parallel, 10ohm resistor(dunno if that's true, would overdrive each led with 120ma), fresnel optics with almost nonexistent spill

p.s.: we always argue about something. he recently switched from canon to nikon, so we can't argue about that anymore... seems like it shifted to flashlights. and of course he thinks $50 for a light is crazy

Re: Nitecore D10 vs. Cateye EL300 - which has brighter hotspot? (converting candela<>

An unenlightened cycling friend of mine had the EL300 and going by memory I wasn't very impressed with it. I think that the D10 might have a brighter hotspot but I just can't really remember enough about the EL300.

Tell him to throw the Cateye in the dump or give it to someone that he doesn't like.

Well, I know that I was impressed with it when I first saw it a few years ago. Pre-flashaholic days...

As far as I remember, it really has an incredible small hotspot, so 30 lumens could beat my D10.

I candela of light intensity (leaving the light source at zero distance) = 1 foot-candle of brightness falling onto a surface at 1 foot = 1 lux of brightness falling onto a surface at 1 meter.

Thanks alot. Assuming the candela measurements were taken at 1m, that'll mean the D10 is 5 times as bright (on 14500). Which should be readily visible, even considering the logarithmic nature of the eye.

I think I just won a beer.


btw, here's the review I got the 500cd from: http://www.burrow.ca/cyclist/reviews/Ozzie-Review-of-Cateye-EL500.txt
just saw that they do note it was taken at 1m.