I saw reference to "bin", which initially I thought was "Buy It Now" (that's what eBay uses)
Now that made me laugh
OK ... my advise ... take it slowly, read and learn, and most of all, enjoy! There is a lot to see and experience, no way you acan get it all in one day.
Let's make a start:
lumens is a unit to measure the luminous flux of a light. Lumens are flux.
Candlepower and lux are unit to measure peak brightness (or just simply brightness) of a light source. Typically we use it to measure the peak brightness of a flashlight's beam. It is a measure for the throw capacity of a light and is not directly correlated with lumens.
To get the idea ... think of an ordinary light bulb that has a lot of lumens but not a very high lux reading as it is all flood ... whereas a laser produces a high lux reading in the spot but has very low lumens.
To measure lux or candlepower, all you need is a luxmeter. It is cheap and a lot of guys have one. To measure flux/lumens, you need an Ulbrichtkugel / Integrating sphere which is expensive and tricky to operate. So few people have one. Don is one of those people.
Then there's the cheating and lying. Normally you'd want to know how much light your torch puts out of the front end, which is what should be measured and supplied by the manufacturer in an ideal world. Unfortunately, some do not have the equipment for this (Int. Sphere) and some just like to inflate their numbers for marketing purposes.
One such thing is quoting "emitter lumens" which is the calculated luminous flux at the emitter (according to a data sheet) for a given drive current. This method does not incorporate the losses of the window and refelctor and whatnot, so it is basically useless.
Surefire tends to underrate their lights, some more, some less. This means you get a guaranteed minimum flux, and most likely more. It is a very fair practice, but also a annoying one as it makes comparisons somewhat tough to do.
In the end, estimating the flux of our lights is a whole science on CPF, it is fun
Have fun exploring the rest ! :wave:
bernie