Horse power top speed or FLUX?

[yaesumofo]

So how do we rate flashlights?
Lux out the front right at one meter?
So that means we can use the emitter ratings in Lumens.
This makes things so simple.

The strength of the emitter is only important in the sense that we know how strong it can be.
The other parts of the equation like OPTIC or REFLECTOR.
Direct drive or regulated?
buck? boost? regulator efficiency?
Current to the emitter? Voltage?

All of those things come into play here. Many of us as Cpf's are interested in most of those specs right?

OK but in the end most people are interested in how bright is it?

Lets face it Horse power (or emitter lumens) does not directly relate to how bright the flashlight is.
It is one part of the picture.
What are your thoughts about how to consistently rate flashlights so that with a single number which gives us really good idea about what a flashlight will do?
Maybe we should come up with a formula something like this: ((Emitter lumens x lux (measured at one meter))*the voltage of the flashlight)) divided by (the width of the reflector or optic in mm X 1000)

Flashlights with more voltage and higher Lumen ratings will have a higher number.
Lights with weaker LED's or less voltage or smaller reflectors will have a smaller number as a result....
So how about it guys. Give it a try. Plug in the numbers for a few flashlights you have and lets compare results.
This formula will produce a number by which flashlights can be compared.
We can call the number something like FLUX.
OK OK call me crazy...
Yaesumofo



Yaesumofo

 

[MikeSalt]

It's at times like this that I realise how difficult it is to get a lux rating these days. Let me take a Raw Ti for example...

(160 x lux x 3.7)/(16 x 1000) = 0.037 x lux

So, as soon as I know the lux, I know this number.

Mike

 

[nerdgineer]

I'm sorta confused by this one. It sounds like you're asking for: 1) a single number metric to compare all flashlights - or at least their photon generating capabilities; and 2) some numerical formula for calculating this metric from specs rather than by taking an empirical measurement - which is what most common reviewers here have elected to do with homemade lightboxes.

In the first area, I have a hard time getting below 2 numerical metrics for comparing flashlights. Mine would be: 1) total output and 2) battery efficiency. Designs which optimize for only one thing at the cost of all else are not very interesting.

As you say, there are so many variables affecting output that (like in antenna design) we rely on measurements rather than theory. In the absence of an affordable absolute measurement standard, everyone uses their own light boxes and offers only comparisons against common makes and models. Imperfect but there it is.

Battery efficiency requires integrating the area under a runtime curve ("eyeball integrating" usually...), scaling it against the peak output, and dividing by the number of batteries used up. Fun to do and you do see trends among manufacturers indicating who in general seems to take more time designing efficiency into their circuits (..*cough*..enix....).

Is there something else you're looking for?..